P. 1

95 . Six , K . M . an d R . A . Goyer . Th e influenc e o f iro n deficien c yo n tissu e conten t an d toxicit yo f ingeste d lea d i n th e rat . J . Lab . Clin . Med . 79:128-136 , 1972 . 96 . Kaplan , M . L. , A . G . Jones , M . A . Davis , an d L . Kopito . Inhibitor yeffec t o f iro n o n th e uptak e o f lea d b y erythrocytes . Lif e Sci . 76:1545-1554 , 1975 . 97 . Sakurai , H. , M . Sugita , an d K . Tsuchiya . Biologica l respons e an d subjectiv e symptom s i n lo wleve l lea d ex posure . Arch . Environ . Health . 29:157-163 , 1973 . 98 . Tola , S. , S . Hernberg , S . Asp , an d J . Nikhanen . Parameter s indicativ e o f absorptio n an d biologica l effec t i n ne wlea d exposure : Aprospectiv e study . Brit . J . Ind . Med . JO : 131-141 , 1973 . 99 . Pueschel , S . M. , L . Kopito , an d H . Schwachman . Childre n wit h a n increase d lea d burden : Ascreenin g an d follo wu p study . J . Am . Med . Assoc . 222(4):462-466 , 1972 . 100 . Rosen , J . F. , C . Zarate-Salvador , an d E . E . Trinidad . Plasm a lea d level s i n norma l an d lead-intoxicate d children . J . Ped. , 84:45-48 , 1974 . 101 . Betts , P . R. , R . Astley , an d D . N . Raine . Lea d intoxicatio n i n childre n i n Birmingham . Brit . Med . J . 7:402-406 , 1973 . 102 . Adebenajo , F . O . Hematologi cstatu s o f urba n blac k childre n i n Philadelphia . Emphasi s o n th e frequenc yo f anemi a an d elevate d bloo d lea d levels . Clin . Pediatr . /5:874-888 , 1974 . 103 . Robinson , M . J , F . E . Karpinski.an d H . Brieger . Th e con centratio n o f lea d i n plasma , whol e bloo d an d erythrocyte s o f infant s an d children . Pediatr . 27:793 , 1958 . 104 . Kochen , J . A . an d Y . Greener . Level s o f lea d i n bloo d an d hematocrit : Implication s fo rth e evaluatio n o f th e newbor n an d anemi cpatient . Pediatr . Res . 7:937-944 , 1973 . 105 . McRoberts , W . Alteratio n i n th e fractionate d bloo d lea d concentratio n i n th e developmen t o f inorgani c lea d poisoning , an d th e concep t o f th e rol e o f "lea d integra tion " i n lea d absorption . J . Soc . Occup . Med . 23:3-18 , 1973 . 106 . Effect s an d dose-respons e relationship s o f toxi cmetals . Proceeding s fro m a n internationa l meetin g organize d b y th e subcommitte e o n th e Toxicolog yo f Metal s o f th e Per manen t Commissio n an d Internationa l Associatio n o n Oc cupationa l Health . Tokyo , Nov . I 823 , 1974 . G . Nordsber g (ed.) . Amsterdam , Elsevier . 1976 . p . 48-49 . 107 . Paglia , D . E. , W . N . Valentine , an d J . G . Dahlgnen . Effect s o f low-leve l lea d exposur e o n pyrimidine-5'-nucleotidas e an d othe rerythrocyt e enzymes . Possibl e rol e o f pyrimidine-5'-nucleotidas e i n th e pathogenesi s o f lead-in duce d anemia . J . Clin . Invest . 56: 1 164- 1 169 , 1975 . 108 . Valentine , W . N „ K . Fink , D . E . Paglia , S . R . Harris , an d W . S . Adams . Hereditar yhemolyti canemi a wit h huma n erythrocyt e pyrimidine-5'-nucleotidas e deficiency . J . Clin . Invest . 54:866-879 , 1974 . 109 . Waldron , H . A . Th e effec t o f lea d o n th e fragilit yo f th e re d cel l incubate d in

vitro. J . Clin . Path . 7 7:405-406 , 1964 . I 10 . Qazi , Q . H . an d D . P . Madahar . Asimpl e rapi d tes t fo r lea d poisoning . J . Pediatr . 79:805-808 , 1971 . 111 . Secchi , G . C , L . Alessi o an d G . Cambiaghi . N a + /K + - ATPas e activit yo f erythrocyt e membranes . Arch . En viron . Health . 27:399 , 1973 . 112 . Hernberg , S. , M . Nurinen . an d J . Hasan . No n rando m shortenin g o f re d cel l surviva l time s i n me n expose d t o lead . Environ . Res . 7:247-261 , 1967 . 113 . Berk , P . D. , D . P . Tschudy , L . A . Shepley , J . G . Waggoner , an d N . I . Berlin . Hematologi can d biochemica l studie s i n a cas e o f lea d poisoning . Amer . J . Med . 48: 137-144, 1970 . 114 . Leikin , S . an d G . Eng . Erythrokineti cstudie s o f th e anemi a o f lea d poisoning . Pediatr . 57:916-1002 , 1963 . 115 . Nakao , K. , O . Wada , an d Y . Yano . Delta-amino-levulini c aci d dehydratas e activit yi n erythrocyte s fo rth e evalua tio n o f lea d poisoning . Clin . Chim . Acta . /9:3l9-325 , .1968 . 116 . d e Bruin . AEffec t o f lea d exposur e o n th e leve l o f 8 - amino-levulinic-dehydratas e activity . Med . Lav . 58:411-418 , 1968 . 117 . Hernberg , S. , J . Nikkanen , G . Mellen , an d H . Lilius . 8 - amino-levulini c aci d dehydratas e as a measur e o f lea d ex posure . Arch . Environ . Health . 27:140-145 , 1970 . 118 . Hernberg , S . an d J . Nikkanen . Enzym e inhibitio n b ylea d unde rnorma l urba n conditions . Lancet . /:63-64 , 1970 . 119 . Millar , J . A. , R . L . C . Cummings , V . Battistini , F . Carswell , an d A . Goldberg . Lea d an d 8-amino-levulini c aci d dehydratas e level s i n mentall yretarde d childre n an d lead-poisone d sucklin g rats . Lancet . 2:695-698 , 1970 . 120 . Secchi , G . C , L . Erba , an d G . Cambiaghi . Delt a amin o levulini caci d dehydratas e activit yo f erythrocyte s an d live rtissu e i n man . Relationshi p t o lea d exposure . Arch . Environ . Health . 28:130-132 , 1974 . 121 . Nieberg , P . I. , L . S . Weiner , B . F . Oski , an d F . A . Oski . Re d bloo d cel l 8-amino-levulini caci d dehydratas e ac tivity . Am . J . Dis . Child . /27:348-350 , 1974 . 122 . Roels , H . A. , J . P . Buchet , R . R . Lauwerys , an d J . Sonnet . Compariso n o f in

vivo effec t o f inorgani clea d an d cad miu m o n glutathion e reductas e syste m an d 8-amino levulinat e dehydratas e i n huma n erythrocytes . Brit . J . Ind . Med . 52:181-192 , 1975 . 123 . Alessio , L. , P . A . Bartazzi , O . Monelli , an d U . Foa . Fre e erythrocyt e protoporphyri n as a n indicato ro f th e biologi ca l effect s o f lea d i n adul t males . II . Compariso n betwee n fre e erythrocyt e protoporphyri n an d othe rindicator s o f effect . Int . Arch . Occup . Environ . Health . 57:89-105 , 1976 . 124 . Wada , O. . Y . Yano , T . Ono , an d K . Toyokawa . Th e diag nosi s o f differen t degree s o f lea d absorption ; i n specia l reference s t o choic e an d evaluatio n o f variou s parameter s indicativ e o f a n increase d lea d absorption . Ind . Health . 7/:55-67 , 1973 . 125 . Wada , O. , K . Takeo , Y . Yano , T . Ono , M . Nagahashi , an d H . Seki . 8-amino-levulini c aci d dehydratas e i n lo wleve l lea d exposure . Arch . Environ . Health . 57:2 1 1-215 , 1976 . I 26 . Granick , O . L. , S . Sassa , S . Granick , R . D . Levere , an d A . Kappas . Studie s i n lea d poisoning . II . Correlatio n betwee n th e rati o o f activate d t o inactivate d 8-amino-levulini caci d dehydratas e o f whol e bloo d an d th e bloo d lea d level . Biochem . Med . 8:149-159 , 1973 . 127 . Roels , H. , R . Lauwerys , J . Buchet , an d G . Hubermont . Effect s o f lea d o n lactatin g rat s an d thei rsucklings . Tox icol . 2:107-113 , 1977 . 128 . Chisholm , J . J. , Jr. , Determinatio n o f 8-amino-levulini c aci d i n plasma . Anal . Biochem . 22:54-64 , 1968 . 129 . Davis , J . R. , R . H . Abrahams , W . I . Fishbein , an d E . A . Fabrega . Urinar ydelt a AL Alevel s i n lea d poisoning . Arch . Environ . Health . 77:164-171 , 1968 . 130 . Specter , M . J. , V . F . Grinee , an d B . Davidow . Th e un suitabilit yo f rando m urinar ydelta-amino-levulini caci d sample s as a screenin g tes t fo rlea d poisoning . J . Pediatr . 79:799-804 , 1971 . 11-5 7P. 2

131 . Blanksma , L . A „ H . K . Sachs , E . F . Murray , an dM . J . O'Connell . Failur e o f

th e urinar y delta-amino-levulini c aci dtes t t o detec t

pediatri c lea dpoisoning . Am . J . Clin . Pathol . 52:96 , 1969 . 132 . Selander , S . an dK . Cramer . Interrelationship s betwee n lea di n blood , lea di n urin e an dAL A i n urin e durin g lea d work . Brit . J . Ind . Med . 27:28-39 , 1970 . 133 . Roels , H . A. , R . R . Lauwerys , J . P . Buchet , an dM . T . Urelust . Respons e o f

free erythrocyt e porphyri n an durin

ar y 8-amino-levulini c aci di n me n an dwome n moderatel y expose dt o lead . Int . Arch . Arbeit s med . 54:97-108 , 1975 . 134 . Moore , M . R . an dP . A . Meredith . Th e associatio n o f 8

- aminolevulini c aci dwit hth e neurologica l an dbehaviora l effect s o f

lea dexposure . Trac e Substance s i n Environ . Healt h- X . Columbia , Missouri . 1976 . p . 363-371 . 135 . Va n De n Bergh , A . A . H . an dW . Grotepass . Porphyrinami e ohn e Porphyrinurie . Klin . Wschr . 72:586-597 , 1933 . 136 . Piomelli , S . an dB . Davidow . Th e FE P (fre e erythrocyt e protoporphyrin ) concentration : A promisin g screenin g tes t fo r lea dpoisoning . Pediatr . Res . 6:366- , 1972 . 137 . Piomelli , S. , A . A . Lamola , M . B . Pho-Fitzpatrick , C . Sea

man , an dL . C . Harber . Erythropoieti c protoporphyri a an dlea dintoxication : Th e molecula r basi s fo r

differenc e i n cutaneou s photosensitivity . J . Clin . Inv . 56(6):1519-1527 , 1975 . 138 . Lamola , A . A. , S . Piomelli , M . B . Pho-Fitzpatrick , T . Yamane , an dL . C . Harber . Erythropoieti c protoporphyri a an dlea dintoxication : Th e molecula r basi s fo r

differenc e i n cutaneou s photosensitivity . J . Clin . Inv . 56(6):1528-1535 , 1975 . 139 . Lamola , A . A . an dT . Yamane . Zin c protoporphyri n i n th e erythrocyte s o f

patient s wit hlea dintoxicatio n an diro n deficienc y anemia . Science . /86:936-938 , 1974 . 140 . Lamola , A . A. , M . Joselow , an dT . Yamane . Zin c pro toporphyri n (ZPP) : A simple , sensitiv e flurometri c screen in g tes t fo r lea dpoisoning . Clin . Chem . 2/ ( I ):93-97 , 1975 . 141 . Flatmark , T . an dI . Romslo . Energy-dependen t accumula

tio n o f iro n b y isolate dra t

live r mitochondria . J . Biol . Chem . 250(16):6433-6438 , 1975 . 142 . Bottomley , S . S. , M . Tanaka , an dM . A . Everett . Diminishe derythroi dferrochelatas e activit y i n pro toporphyria . J . Lab . Clin . Med . 86(0:126-131 , 1975 . 143 . Boukowsky , H . L. , J . R . Bloomer , P . S . Ebert , an dM . J . Mahoney . Hem e synthetas e deficienc y i n huma n pro toporphyria . J . Clin . Invest . 56(5):1139-1148 , 1975 . 144 . Alvares , A . P. , S . Leigh , J . Cohn , an dA . Kappas . Lea dan d methy l mercury : Effect s o f acut e exposur e o n cytochrom e P-45 0 an dmixe dfunctio n oxidas e syste mi n th e liver . J . Exp . Med . 755:1406-1409 , 1972 . 145 . Whetsell , W . O. , Jr. , S . Sassa , an dA . Kappas . Studie s o f porphyri n biosynthesi s an dlea deffec t o f organotypi c culture s o f

chic k dorsa l roo t

ganglion . Pape r

presente da t America n Associatio n o f Neuropathologists , Toronto , Canada , March , 1977 . 146 . Cente r

fo r Diseas e Control . Increase dlea dabsorptio n an d lea dpoisonin g i n youn g children . J . Pediatr . 87(5):824-830 , 1975 . 147 . Piomelli , S . A micrometho dfo r fre e erythrocyt e pro toporphyrins : Th e FE P test . J . Lab . Clin . Med . 87:932-940 , 1973 . 148 . Piomelli , S. , B . Davidow , V . F . Guinee , P . Young , an dG . Gay . Th e FE P (fre e erythrocyt e protoporphyrin ) test : A screenin g micrometho dfo r lea dpoisoning . Pediatr . 57:254-259 , 1973 . 149 . Kamholtz , L . P. , L . G . Thatcher , F . M . Blodgett.an dT . A . Good . Rapi dprotoporphyri n quantitatio n fo r detectio n o f lea dpoisoning . Pediatr . 50:625 , 1972 . 150 . Sassa , S. , L . J . Granick , S . Granick , A . Kappas , an dR . D . Levere . Studie s i n lea dpoisoning . I . Microanalysi s o f erythrocyt e protoporphyri n level s b y spectrofluorometr y i n th e detectio n o f

chroni c lea dintoxicatio n i n th e sub

clinica l range . Biochem . Med . 8:135-148 , 1973 . 151 . McLaren , G . D. , W . F . Barthel , an dP . Landrigan . Screen

in g fo r lea dpoisoning : Measurement s an dmethodolog y (Letter) . Pediatr . 52:303 , 1973 . 152 . Piomelli , S. , B . Davidow , an dV . F . Guinee . Screenin g fo r lea dpoisoning : Measurement s an dmethodolog y (Letter) . Pediatr . 52:304 , 1973 . 153 . Chisholm , J . J. , Jr . an dD . H . Brown . Micro-scal e photo

fluorometri c determinatio n o f "fre e erythrocyt e porphyrin " (protoporphyri n IX) . Clin . Chem . 27:1669-1682 , 1975 . 154 . Chisholm , J . J. , Jr . Screenin g fo r pediatri c lea dpoisoning . Arch . Hig . Rod aToksikol . 26(Suppl.):61-79 , 1975 . 155 . Landrigan , P . J. , E . L . Baker , Jr. , R . G . Feldman , D . H . Cox , K . V . Eden , W . A . Orenstein , J . A . Mather , A . J . Yankel , an d1 . H . vo n Lindern . Increase dlea dabsorptio n wit hanemi aan dslowe dnerv e conductio n i n childre n nea r alea dsmelter . J . Pediatr . 89:904-910 , 1976 . 156 . Hanna , T . L. , D . N . Dietzler , C . H . Smith , S . Gupta , an d H . S . Zarkowsky . Erythrocyt e porphyri n analysi s i n th e detectio n o f

lea dpoisonin g i n children : Evaluatio n o f fou r micromethods . Clin . Chem . 22:161-168 , 1976 . 157 . Stuik , E . J . Biologica l respons e o f mal e an dfemal e volun

teer s t o inorgani c lead . Int . Arch . Arb . Med . 55:83-97 , 1974 . 158 . Tomokuni , K . an dM . Ogata . Relationshi p betwee n lea d concentratio n i n bloo dan dbiologica l respons e fo r porphyri n metabolis mi n worker s occupationall y expose d t o lead . Arch . Toxicol . 55:239-246 , 1976 . 159 . Roels , H. , J . P . Buchel , R . Lauwerys , G . Hubermont , P . Bruaux , F . Claeys-Thoreau , A . L aFontaine , an dJ . Va n Overschelde . Impac t

o f ai r pollutio n b y lea do n th e hem e biosyntheti c pathwa y i n school-ag e children . Arch . En

viron . Healt h57:310-316 , 1976 . 160 . Reigert , J . R . an dN . H . Whitlock . Longitudina l observa

tion s o f th e relationship s betwee n fre e erythrocyt e porphyrin s an dwhol e bloo dlead . Pediatr . 57:54-59 , 1976 . 161 . Levi , D . T. , A . S . Curran , S . D . Alexander , B . Davidow , an dS . Piomelli . Physiologica l significanc e o f erythrocyt e protoporphyri n (EP ) i n moderat e bod y lea dburden . Pediatr . Res . 70:378 , 1976 . 162 . Chisholm , J . J. , M . B . Barrett , an dH.V.Harrison . Indica

tor s o f interna l dos e o f

lea di n relatio n t o derangemen t i n hem e synthesis . John s Hopkin s Med . J . 757:6-12 , 1975 . 163 . Piomelli , S. , A . Brickman , an dE . Carlos . Rapi ddiagnosi s o f iro n deficienc y b y measuremen t o f fre e erythrocyt e porphyrin s an dhemoglobin : Th e FEP/hemoglobi n ratio . Pediatr . 57:136-141 , 1976 . 164 . McLaren , G . D. , J . T . Carpenter , Jr. , an dH . V . Nino . Erythrocyt e protoporphyri n i n th e detectio n o f iro n defi

ciency . Clin . Chem . 27 : 1121-1127 , 1975 . 11-5 8P. 3

165 . Dagg , J . H. , A . Goldberg , an dA . Lockhead . Value s o f 187 . erythrocyt e protoporphyri n i n th e diagnosi s o f

laten t iro n deficiency . Brit . J . Haematol . 72:326-330 , 1966 . 166 . Koenig , H . M . an dA . L . Lightsey . Th e micromeasuremen t 188 . o f fre e erythrocyt e an dprotoporphyri n (FEP ) a s amean s o f differentiatin g Alpha-thalassemi atrai t fro miro n defi

- 189 . cienc y anemia . Pediatr . Res . 8:404 , 1974 . 167 . Koenig , H . M. , A . L . Lightsey , an dJ . E . Schanberger . Th e 190 . micromeasuremen t

o f fre e erythrocyt e protoporphyri n a s amean s o f

differentiatin g Alpha-thalassemi atrai t fro m iro n deficienc y anemia . J . Pediatr . 86:539-541 , 1975 . 191 . 168 . Stockman , J . A. , Ill , L . R . Weiner , J . G . E . Simon , M . J . Stuart , an dF . A . Oski . Th e measuremen t o f fre e erythrocyt e porphyri n (FEP ) a s asimpl e mean s o f dis

- 192 . tinguishin g iro n deficienc y fro mBeta-thalassemi atrai t i n subject s withmicrocytosis . J . Lab . Clin . Med . 85:1 1 3- 1 19 , 193 . 1975 . 169 . Piomelli , S. , C . Seaman , D . Zullow , A . Curran , an dB . Davidow . Metaboli c evidenc e o f lea dtoxicit y i

n "normal " 194 . urba n children . Clin . Res . 25:495A , 1977 . (Abstract) . 170 . Wada , O , Y . Yano , K . Toyokawa , T . Suzuki , S . Suzuki , 195 . an dH . Katsunuma . Huma n response s t o lead ; i n specia l referenc e t o porphyri n metabolis mi n bon e marro w 196 . erythroi dcell s an dclinica l an dlaborator y study . Ind . Health . 70:84-92 , 1972 . 171 . Granick , S . an dR . D . Levene . Hem e synthesi s i n erythroi d197 . cells . Prog , i

n Hematol . 4:1-47 , 1964 . 172 . Kreimer-Birnbaum , M . an dM . Grinstein . Porphyri n bio

- 198 . synthesis . III . Porphyri n metabolis mi n experimenta l lea d poisoning . Biochim . Biophys . Acta . 7/7: 1 10-123 , 1965 . 199 . 173 . Piper , W . N . an dT . R . Tephly . Differentia l inhibitio n o f erythrocyt e an dhepati c uroporphyrinoge n I synthetas e b y lead . Lif e Sci . 74 : 873-876 , 1974 . 200 . 174 . Kassenaar , A. , H . Morell , an dI . M . London . Th e incor

poratio n o f

glycin e int o globi n an dth e synthesi s o f hem e i n duc k erythrocytes . J . Biol . Chem . 229:423-435 , 1957 . 201 . 175 . White , J . M . an dD . R . Harvey . Defectiv e synthesi s o f alpha.an dbet aglobi n chain s i n lea dpoisoning . Nature . 256:71-73 , 1972 . 202 . 176 . Ali , M . A . M . an dA . Quinlan . Effec t o f lea do n globi n synthesi s in vitro. Am . J . Clin . Pathol . 67:77-79 , 1977 . 203 . 177 . Environmenta l Healt hCriteri afo r Lead . Geneva . Worl d Healt hOrganization . 1977 . In press . 204 . 178 . Janquera l De s Planches , L . Trait e de s Maladie s d e Plum b o u Saturnines . Paris , Terra , Librair e Editeur , Vol . 2 , 1839 . 205 . 179 . Stewart , D . D . Lea dconvulsions . Amer . J . Med . Sci . 709:288-306 , 1895 . 180 . Oliver , T . Lea dpoisonin g an dth e race . Brit . Med . J . /:1096-I098 , 1911 . 206 . 181 . Prendergast , W . P . Th e classificatio n o f th e symptom s o f lea dpoisoning . Brit , Med . J . 7: 1 164- 1 166 , 1910 . 182 . Blackfan , K . D . Lea dpoisonin g i n childre n withespecia l referenc e t o lea da s acaus e o f convulsions . Amer . J . Med . 207 . Sci . 755:877-887 , 1917 . 183 . Aub , J . C , L . T . Fairhill , A . S . Minot , an dP . Reznikoff . 208 . Lea dpoisoning . Med . (Baltimore) . 4:250 , 1925 . 184 . Cantarow , A . an dM . Trumper . Lea dPoisoning . 209 . Baltimore , William s an dWilkins . 1944 . 185 . Cumings , J . N . Heav y Metal s an dth e Brain . Oxford , Blackwel l Scientifi c Publications . 1959 . p . 95-155 . 186 . Teisinger , J . an dV . Styblova . Neurologica l pictur e o f 210 . chroni c lea dpoisoning . Act aUniversitati s Carolina e - Med . Supp . 74:199-206 , 1961 . Smith , F . L. , T . K . Rathmell , an dG . W . Marcil . Th e earl y diagnosi s o f

acut e an dlaten t

plumbism . Amer . J . Clin . Pathol . 8:471-508 , 1938 . Giannattsig , R . C , A . V . Bedo , an dM . J . Pirozzi . Lea d poisoning . Amer . J . Dis . Child . 84:316-321 , 1952 . McKhann , C . F . an dE . C . Vogt . Lea dpoisonin g i n children . Amer . J . Dis . Child . 52:386-392 , 1926 . Greengard , J. , B . Adams , an dE . Berman . Acut e lea den cephalopath y i n youn g children . J . Pediatr . 66:707-711 , 1965 . Ennis , J . M . an dH . E . Harrison . Treatmen t o f lea den cephalopath y wit hBA L(2, 3 dimercaptopropanol) . Pediatr . 5:853-868 , 1950 . Agerty , H . W . Lea dpoisonin g i n children . Med . Clin . N . Amer . 56(6) : 1587-1597 , 1952 . Mellins , R . B . an dC . D . Jenkins . Epidemiologica l an d psychologica l stud y o f lea dpoisonin g i n children . J . Amer . Med . Assoc . 758:15-20 , 1955 . Levinson , W . an dM . Zeldes . Lea dintoxicatio n i n children . Arch . Pediatr . 56:738-748 , 1939 . Tanis , W . L . Lea dpoisonin g i n children . Amer . J . Dis . Child . 89:325-331 , 1955 . Lewis , B . W. , R . J . Collins , an dH . S . Wilson . Seasona l in

cidenc e o f

lea dpoisonin g i

n childre n i

n St . Louis . S . Med . J . 48:298-301 , 1955 . Blackman , S . S . Th e Lesion s o f Lea dEncephalopath y i n Children . Bull . John s Hopkin s Hosp . 67:1-43 , 1937 . Pentschew , A . Morpholog y an dmorphogenisi s o f lea den cephalopathy . Acta . Neuropath . 5:133-160 , 1965 . Popoff , W. , S . Weinberg , an d1 . Feigin . Pathologi c obser

vation s i n lea dencephalopath y with specia l referenc e t o th e vascula r

changes . Neurol . 75:101-112 , 1963 . Fullerton , P . M . Chroni c periphera l neuropath y produce d b y lea dpoisonin g i

n guine apigs . J . Neuropath . Exp . Neurol . 25:214-236 , 1976 . Lampert , P . W . an dS . S . Schochit , Jr . Demyelinatio n an d remyelinatio n i

n lea dneuropathy . J . Neuropath . Exp . Neurol . 27(4):527-545 , 1968 . Emmerson , B . T . Th e clinica l differentiatio n o f lea dgou t fro mprimar y gout . Arthritis . Rheum . 7/:623-634 , 1968 . Cohen , G . J . an dW . E . Ahrens . Chroni c lea dpoisoning . J . Pediatr . 54:271-284 , 1959 . Keho e R . A . Th e metabolis mo f lea di n ma n i

n healt han d disease . I . Th e norma l metabolis mo f lead . R . Inst . Publi c Healt hHyg . J . 24:81-97 , 1961 . (Harbe n Lectures , 1960) . Kehoe , R . A . Th e metabolis mo f lea di n ma n i

n healt han d disease . II . Th e metabolis mo f lea dunde r

abnorma l condi

tions . R . Inst . Publi c Healt hHyg . J . 24:129-143 , 1961 . (Harbe n Lectures , 1960) . Kehoe , R . A . Th e metabolis mo f lea di n ma n i n healt han d disease . III . Presen t

hygieni c problem s relatin g t o th e ab

sorptio n o f

lead . R . Inst . Publi c Healt hHyg . J . 24:177-203 , 1961 . (Harbe n Lectures , 1960) . Chisholm , J . J . Chroni c lea dintoxicatio n i n children . Develop . Med . Chil dNeurol . 7:529-536 , 1965 . Gant , V . A . Lea dpoisoning , lndust . Med . 7:679-699 , 1938 . Bradley , J . E. , A . E . Powell , W . Niermann , K . R . McGrady , an dE . Kaplan . Th e incidenc e o f abnorma l bloo dlevel s o f

lea di n ametropolita n pediatri c clinic . J . Pediatr . 49:1-6 , 1956 . Bradley , J . E . an dR . J . Baumgartner . Subsequen t menta l developmen t

o f childre n wit hlea dencephalopathy , a s re late dt o typ e o f

treatment . J . Pediatr . 55:311-315 , 1958 . 1 1 -5 9P. 4

211 . Rummo.J . H . Intellectua l an dBehaviora l Effect s o f Lea d Poisonin g i n Children . Ph.D . thesis , Universit y o f Nort h Carolina , Chape l Hill , N.C. , An n Arbor , Mich. , Universit y o f Mich . Microfilms . 1974 . 212 . Shannon , H . S. , M . K . Williams , an dE . King . Sicknes s ab

senc e o f lea dworker s an dcontrols . Brit . J . Indus . Med . 55:236-242 , 1976 . 213 . Robinson , T . R . Th e healt ho f lon g servic e tetraethy l lea d workers . J . Occup . Med . 78:31-40 , 1976 . 214 . Morgan , B . B . an dJ . D . Repko . Evaluatio n o f behavioura l function s i n worker s expose dt o lead . In: C . Xintaras , B . L . Johnson , an dI . DeGroo t (eds.) . Behavioura l Toxicology . Earl y Detectio n o f

Occupationa l Hazards . Washington , D.C , U.S . Dept . o f

Health , Educatio n an dWelfare , 1974 . 215 . Milburn , H. , E . Mitran , an dG . W . Crockford . A n in

vestigatio n o f

lea dworker s fo r

subclinica l effect s o f

lea d usin g thre e performanc e tests . Ann . Occup . Hyg . 79:239-249 , 1976 . 216 . Seppalainen , A . M . Application s o f neurophysiologica l method s i n occupationa l medicine : A review . Scand . J . Wor k Environ . Health . 7:1-14 , 1975 . 217 . Sessa , T. , E . Ferrari , an dC . Colucci . D'amat o velocita'd i conduzion e nervos ane i saturnini . Foli aMed . 48:658-668 , 1965 . 218 . Catton , M . J. , M . J . G . Harrison , P . M . Fullerton , an dG . Kazantzis . Subclinica l neuropath y i n lea dworkers . Brit . Med . J . 2:80-82 , 1970 . 219 . Seppalainen , A . M . an dS . Hernberg . Sensitiv e techniqu e fo r detectin g subclinica l lea dneuropathy . Brit . J . Industr . Med . 29:443-449 , 1972 . 220 . Seppalainen , A . M. , S . Tola , S . Hernberg , an dB . Kock . Subclinica l neuropath y a t "safe " level s o f

lea dexposure . Arch . Environ . Health . 50:180-183 , 1975 . 221 . Melgaard , B. , J . Causen , an dS . C . Rastogi . Electromyographi c change s i n automechanic s wit h in

crease dheav y meta l levels . Act aNeurol . Scand . 54:227-240 , 1976 . 222 . Araki , A . R . Periphera l neuropath y at lo w leve l industria l lea dexposures . Scand . J . Wor k Environ . Health . 2:225-228 , 1976 . 223 . D e l aBurde , B . an dM . S . Choate . Doe s asymptomati c lea dexposur e i n childre n hav e laten t sequelae ? J . Pediatr . 87:1088-1091 , 1972 . 224 . D e laBurde , B . an dM . S . Choate . Earl y asymptomati c lea dexposur e an ddevelopmen t a t schoo l age . J . Pediatr . 87:638-642 , 1975 . 225 . Perino , J . an dC . B . Ernhart . Th e relatio n o f subclinica l lea dleve l t o cognitiv e an dsensorimoto r impairmen t

i n blac k preschoolers . J . Learn . Dis . 7:26-30 , 1974 . 226 . Albert , R . E. , R . E . Shore , A . J . Sayers , C . Strehlow , T . J . Kneip , B . S . Pasternack , A . J . Freidhoff , F . Covan , an dJ . A . Cimino . Follow-u p o f childre n overexpose dt o lead . Environ . Healt hPerspec . 7:33-40 , 1974 . 227 . Landrigan , P . J. , R . H . Whitworth , R . W . Baloh , N . W . Staehling , W . F . Barthel , an dB . T . Rosenblum . Neuro

psychologica l dysfunctio n i n childre n wit hchroni c low

leve l lea dabsorption . Lance t 7:708-712 , 1975 . 228 . Kotok , D . Developmen t o f childre n wit helevate dbloo d levels : A controlle dstudy . J . Pediatr . 80:57-61 , 1972 . 229 . Lansdown , R . G. , J . Shepherd , B . E . Clayton , H . T . Delves , P . J . Graham , an dW . C . Turner . Blood-lea d levels , behavior , an dintelligence . A populatio n study . Lancet . 7:538-541 , 1974 . 230 . McNeil , J . L. , J . A . Ptasnik , an dD . B . Croft . Evaluatio n o f long-ter meffect s o f

elevate dbloo dlea dconcentration s i n asymptomati c children . Arhiv . Hig . Rada . Toksikol . 74:97-119 , 1975 . 231 . Landrigan , P.J. , E.L . Baker , R.G . Feldman , D.H . Cox , K.V . Eden , W.A . Orenstein , J.A . Mather , A.J . Yankel , an d I.H . vo n Lindern . Increase dlea dabsorptio n wit hanemi a an dslowe dnerv e conductio n i n childre n nea r

alea d smelter . J . Pediatr . 89:904-910 , 1976 . 232 . Kotok , D. , R . Kotok , an dT . Heriot . Cognitiv e evaluatio n o f childre n wit helevate dbloo dlea dlevels . Amer . J . Dis . Child . 757:791-793 , 1977 . 233 . McCall , R . B. , P . Hogarty , N . Hurlburt . Transition s i n in

fan t sensorimoto r

developmen t

an dth e predictio n o f childhoo dIQ . Am . Psychologist . 27:728-748 , 1972 . 234 . Elardo , Richard , R . Bradley , B . M . Caldwell . Th e relatio n o f infants ' hom e environment s t o menta l tes t performanc e fo r si x t o thirty-si x months : A longitudina l analysis . Chil d Develop . 46:71-76 , 1975 . 235 . Ivanans , T . Effec t o f materna l educatio n an dethni c back

groun do n infan t

development . Arch . Dis . i n Childhood . 50:454 , 1975 . 236 . David , O. , J . Clark , an dK . Voeller . Lea dan dhyperac

tivity . Lancet . 7:900-903 , 1972 . 237 . Klein , V . C , J . W . Sayre , an dD . Kotok . Lea dpoisoning . Curren t statu s o f

th e proble mfacin g pediatricians . Am . J . Dis . Child.727:805-807 , 1974 . 238 . Bicknell , J „ B . E . Clayton , an dH . Y . Delves . Lea di n men tall y retarde dchildren . J . Menta l Def. Res . 72:282-293 , 1968 . 239 . Baloh , R. , R . Sturm , B . Green , an dG . Gleser . Neuro

psychologica l effect s o f chroni c asymptomati c increase d lea dabsorption . A controlle dstudy . Arch . Neurol . 52:326-330 , 1975 . 240 . Pihl , R . O . an dM . Parkes . Hai r elemen t conten t i n learn

in g disable dchildren . Science . 798:204-206 , 1977 . 241 . Beattie , A . D. , M . R . Moore , A . Goldberg , M . J . Finlayson , J . F . Graham , T . M . Mackie , J . C . Main , P . A. ' McLaren , K . M . Murdock , an dF . T . Stewart . Rol e o f chroni c low-leve l lea dexposur e i n th e aetiolog y o f menta l retardation . Lancet . 7(7907):589-592 , 1975 . 242 . Moore , M . R. , P . Meredith , an dA . Goldberg . A retrospec tiv e analysi s o f

bloo dlea di n mentall y retarde dchildren . Lancet . 7(8014):717-719 . 1977 . 243 . Seto , D . S . Y . an dJ . M . Freeman . Lea dneuropath y i n childhood . Amer . J . Dis . Child . 707:337-342 , 1964 . 244 . Anku , V . D . an dJ . W . Harris . Periphera l neuropath y an d lea dpoisonin g i n achil dwit h sickle-cel l anemia . J . Pedia . 85:337-340 , 1974 . 245 . Erenberg , G. , S . S . Rinsler , an dB . G . Fish . Lea dneuropa th y an dsickl e cel l disease . Pedia . 54:438-441 , 1974 . 246 . Thomas , J . A. , F . D . Dallenbach , an dM . Thomas . Con

sideration s o f

th e developmen t

o f experimenta l lea den cephalopathy . Virch . Arch . Abt . A . Path . Anat . 552:61-74 , 1971 . 247 . Michaelson , I . A . an dM . W . Sauerhoff . A n improve d mode l o f lead-induce dbrai n dysfunctio n i n th e sucklin g rat . Toxicol . Appl . Pharmacol . 28:88-96 , 1974 . 248 . Krigman , M . R . an dE . L . Hogan . Effec t o f lea dintoxica

tio n o n th e postnata l growt h o f th e ra t nervou s system . En

vir . Healt hPersp . 7:187-199 , 1974 . 11-6 0P. 5

249 . Clasen , R . A. , 1 . F . Hartmann , P . S . Coogan , S . Pandolfi , I . Laing , an dR . A . Becker . Experimenta l acut e lea den cephalopath y i

n th e juvenil e Rhesu s monkey . Envir . Healt hPersp . 7:175-185 , 1974 . 250 . Rosenblutn , W . I . an dM . G . Johnson . Neuropathologi c change s produce di

n sucklin g mic e b y addin g lea dt o th e materna l diet . Arch . Path . 85:640-648 , 1968 . 251 . Wells , G . A . H. , J . McC . Howell , an dC . Gopenath . Ex

perimenta l lea dencephalopath y o f calves . Histologica l observation s o n th e natur e an ddistribution s o f th e lesions . Neuropath . Appl . Neurobiol . 2:175-190 , 1976 . 252 . Bouldin , T . W. , P . Mushak , L . A . OTuama , an dM . R . Krigman . Blood-brai n barrie r dysfunctio n i n acut e lea d encephalopathy : A reappraisal . Environ . Healt h Perspect . 72:81-88 , 1975 . 253 . Bull , R . J. , P . M . Stanaszek , J . J . O'Neill , an dS . D . Lutkenhoff . Specificit y o f th e effect s o f

lea do n brai n energ y metabolis mfo r

substrate s donatin g acytoplasmi c reducin g equivalent . Environ . Healt hPerspect . 72:89-95 , 1975 . 254 . Dobbing , J . Undernutritio n an dth e developin g brain . In: Developmenta l Neurobiology . W.A . Hamwic h (ed. ) Springfield , III . C . C . Thoma s Co . 1970 . 255 . Altman , J . Nutritiona l deprivatio n an dneura l develop

ment . In: Brai n Developmen t an dBehavior . M . B . Ster

man , D . J . McGinty , an dA . M . Andenolf i (eds. ) Ne w York , Academi c Press . 1971 . 256 . Castellano , C . an dA . Oliverio . Earl y malnutritio n an d postnata l change s i n brai n an dbehavio r i n th e mouse . Brai n Res . 707:317-325 , 1976 . 257 . Eckhert , C . D. , R . H . Barnes , an dD . A . Levitsky . Regiona l change s i n ra t brai n cholin e acetyltransferas e an dacetylcholinesteras e activit y resultin g fro munder

nutritio n impose ddurin g differen t period s o f

develop

ment . J . Neurochem . 27:277-283 , 1976 . 258 . Reiter , L . W . Behaviora l toxicology : Effect s o f postnata l exposur e t o neurotoxin s o n developmen t o f locomoto r

ac tivit y i n th e rat . J . Occup . Med . 79(3):20l-204 , 1977 . 259 . Goyer , R . A . an dK . R . Mahaffey . Susceptibilit y t o lea d toxicity . Environ . Healt hPerspec . 2:73-80 , 1972 . 260 . Michaelson , I . A . Effect s o f inorgani c lea do n RNA , DNA , an dprotei n conten t

i n th e developin g neonata l ra t brain . Toxicol . Appl . Pharmacol . 26:539-548 , 1973 . 261 . Gray , L . E . an dL . W . Reiter . Lead-induce ddevelopmen

ta l an dbehaviora l change s i n th e mouse . Presente dat th e 16thAnnua l Meetin g o f th e Societ y o f

Toxicology , Toron

to , Ontario , Canada , March , 1977 . 262 . Silbergeld , E . K. , an dA . M . Goldberg . A lead-induce d behaviora l disorder . Lif e Science . 75:1275-1283 , 1973 . 263 . Maker , H . S. , G . M . Lehrer , an dD . J . Silides . Th e effec t o f lea do n mous e brai n development . Environ . Res . 70:76-91 , 1975 . 264 . Reiter , L . W. , G . E . Anderson , J . W . Laskey , an dD . F . Cahill . Developmenta l an dbehaviora l change s i n th e ra t durin g chroni c exposur e t o lead . Environ . Healt h Perspec . 72:119-123 , 1975 . 265 . Kimmel , C . A. , L . D . Grant , an dC . S . Sloan . Chroni c lea d exposure : Assessmen t

o f developmenta l toxicity . Teratol . 75:27A , 1976 . (Abstract ) 266 . Der , R. , Z . Fahim , D . Hilderbrand , an dM . Fahim . Com

bine deffect s o f

lea dan dlo w protei n die t o n growth , sex ua l developmen t

an dmetabolis mo n femal e rats . Res . Comm . Chem . Path . Pharmacol . 9:723-738 , 1974 . 267 . Tapp , J . T . Activity , reactivit y an dth e behavior-directin g propertie s o f

stimuli . In: Reinforcemen t an dBehavior . J . T . Tap p (ed.) . Ne w York , Academi c Press . 1969 . 268 . Copobianco , S . an dL . W . Hamilton . Effect s o f interrup

tio n o f limbi c system s pathway s o n differen t measure s o f activity . Physiol . Behav . 7 7:65-72 , 1976 . 269 . Allen , J . R. , P . J . McWey , an dS . J . Tomi . Pathobiologica l an dbehaviora l effect s o f lea dintoxicatio n i

n th e infan t Rhesu s monkey . Environ . Healt hPerspect . 7:239-246 , 1976 . 270 . Bornschein , R . L. , I . A . Michaelson , D . A . Fox , an dR . Loch . Evaluatio n o f

Anima l Model s Use dt o Stud y Effect s o f Lea do n Neurochemistr y an dBehavior . Symposi ao n Biochemica l Effect s o f

Environmenta l Pollutants . U.S . En

vironmenta l Protectio n Agency . Cincinnati , Ohio . 1976 . 271 . Brown , D . R . Neonata l lea dexposur e i n th e rat : Decrease dlearnin g a s afunctio n o f ag e an dbloo dlea d concentrations . Toxicol . Appl . Pharmacol . 52:628-637 , 1974 . 272 . Driscoll , J . W . an dS . E . Stegner . Behaviora l effect s o f chroni c lea dingestio n o n laborator y rats . Pharmacol . Biochem . Behav . 4:411-417 , 1976 . 273 . Hastings , L. , F . P . Cooper , an dR . L . Bornschein . Effect s o f earl y lea dexposur e o n behavio r o f developin g rats . Toxicol . Appl . Pharmacol . 37: 162 , 1976 . 274 . Kostas , J. , D . J . McFarland , an dW . G . Drew . Lead-in

duce dhyperactivity . Chroni c exposur e durin g th e neonata l perio di n th e rat . Pharmacol.74:435-442 , 1976 . 275 . Overmann , S . R . Behaviora l effect s o f asymptomati c lea d exposur e durin g neonata l developmen t i n rats . Toxicol . Appl . Pharmacol . (I n Press) . 276 . Reiter , L . W. , G . E . Anderson , M . E . Ash , an dL . E . Gray . Locomoto r

measurement s i n behaviora l toxicology : Effect s o f

lea dadministratio n o n residentia l maz e behavior . In: Behaviora l Toxicology : An Emergin g Dis

cipline . H . Zanuc k

an dL . W . Reite r

(eds.) . U.S . Govt . Printin g Office . 1977 . 277 . Cahill , D . F. , L . W . Reiter , J . A . Santolucito , G . I . Rehnberg , M . E . Ash , M . J . Favor , S . J . Bursian , J . F . Wright , an dJ . W . Laskey . Biologica l assessmen t o f con tinuou s exposur e t o tritiu man dlea di n th e rat . In: Biologi

ca l Effect s o f

Lo w Leve l Radiation . Internationa l Atomi c Energ y Agency , Vienna . 2:65-78 , 1976 . 278 . Sauerhoff , M . W . an dI . A . Michaelson . Hyperactivit y an d brai n catecholamine s i n lead-expose ddevelopin g rats . Science . 782:1022-1024 , 1974 . 279 . Sauerhoff , M . W . Neurochemica l Correlate s o f Lea dEn

cephalopath y i n the-Developin g Rat . Doctora l Disserta

tion . Univ . o f

Cincinnati . An n Arbor , Univ . Microfilms . 1974 . 280 . Silbergeld , E . K . an dA . M . Goldberg . Hyperactivity : A lea dinduce dbehavio r

disorder . Environ . Healt h Perspect . 7:227-232 , 1974 . 281 . Silbergeld , E . K . an dA . M . Goldberg . Lead-induce d behaviora l dysfunction : An anima l mode l o f hyperactivity . Exp . Neurol . 42:146-157 , 1974 . 282 . Sobotka , T . J . an dM . P . Cook . Postnata l lea dacetat e ex posur e i n rats : Possibl e relationshi p t o minima l brai n dys

function . Amer . J . Ment . Defic . 79:5-9 , 1974 . 283 . Sobotka , T . J. , Brodie , R . E. , an dM . P . Cook . Psy

chophysiologi c effect s o f earl y lea dexposure . Toxicol . 5:175-191 , 1975 . 11-6 1P. 6

284 . Sobotka , T. , E . Miller , an dS . Spaid . Neurobehaviora l cor relate s o f

earl y lea dexposur e i n beagl e dogs . Proc . Fed . Am . Soc . Exper . Biol . 55:355 , 1977 . 285 . Winneke , G. , A . Brockhaus , an dR . Baltisson . Neurobehaviora l an dsystemi c effec t o f long-ter mblood

lea delevatio n i n rats . I . Discriminatio n learnin g an d open-fiel dbehavior . Arch , o f Toxicol . 57:247-263 , 1977 . 286 . Zenick , H. , E . Eschenback , an dR . Padich . Effect s o f developmenta l lea dexposur e o n subsequen t offsprin g ac tivit y i n a n ope n field . Environ . Healt hSci . (submitted) . 287 . Campbell , B . A. , L . D . Lytle , an dH . C . Fibiger . Ontogen y o f adrenergi c arousa l an dcholinergi c inhibitor y mechan

ism s i n th e rat . Science . 766:635-637 , 1969 . 288 . Wender , P . H . Minima l brai n dysfunctio n i n children . Wile y lnterscience , Ne w York . 1971 . p . 75 . 289 . Reiter , L . W. , L . E . Gray , an dA . M . Goldberg . Th e effect s o f lea dexposur e o n amphetamine-induce dlocomoto r ac tivit y i n th e mouse . Environ . Healt hSci . (submitted) . 290 . Randrup , A . an d1 . Munkvad . Biochemical , anatomica l an dpsychologica l investigation s o f stereotype dbehaviou r induce db y amphetamines . In: Amphetamine s an dRelate d Compounds . E . Cost aan dS . Garattin i (eds. ) Rave n Press , Ne w York . 1970 . p . 695-713 . 291 . Weiner , G . Varyin g psychologica l sequela e o f lea dinges

tio n i n children . Pub . Healt hRep . 85:19-24 , 1970 . 292 . Brady , K. , Y . Werrera , an dH . Zenick . Influenc e o f paren ta l lea dexposur e o n subsequen t learnin g abilit y o f offspring . Pharmacol . Biochem . Behav . 5:561-565 , 1975 . 293 . Brown , S. , N . Dragann , an dW . H . Vogel . Effect s o f lea d acetat e o n learnin g an dmemor y i n rats . Arch . Environ . Healt h22:370-372 , 1971 . 294 . Overmann , S . Behaviora l effect s o f asymptomati c develop

menta l plumbis mi n rats . Unpublishe dDoctora l Disserta

tion , Michiga n Stat e University . 1976 . 295 . Snowdon , C . T . Learnin g deficit s i n lead-injecte drats . Pharmacol . Biochem . Behav . 7:599-603 , 1973 . 296 . Slecta , D . Effect s o f chroni c lea dadministratio n o n fixed interva l performance s i n rat . Unpublishe dDoctora l Dis

sertation , Universit y o f Minnesota . 1977 . 297 . Shapiro , M . N. , J . N . Tritschler , an dR.A . Ulm . Lea dcon tamination : Chroni c an dacut e behaviora l effect s i n th e albin o rat . Bull . Psychom . Soc . 2(2):94-96 , 1973 . 298 . Bornschein , R. , T . E . Levine , an dI . A . Michaelson . Effect s o f

neo-nata l lea dexposur e o n visua l discrimina

tio n learnin g i n mice . Pharmacologist . 78 : 125 , 1976 . 299 . Bornschein , R . L . Locomoto r activit y o f

lead-expose d mice . In: Th e Effect s o f Lea dExposur e o n CN S Function : A Worksho p o n Anima l Models . Sponsore db y th e U.S . Environmenta l Protectio n Agency . Hendersonville , Nort h Carolina , Octobe r

1976 . 300 . VanGelder , G. , T . Carson , R . Smith , an dW . Buck . Behaviora l toxicologi c assessmen t o f neurologi c effec t

o f lea di n sheep . Clin . Toxicol . 6:404-418 , 1973 . 301 . Carson , T. , G . VanGelder , G . Karas , an dW . B . Buck . Slowe dlearnin g i n lamb s prenatall y expose dt o lead . Arch . Environ . Health . 29:154 , 1974 . 302 . Carson , T . L . Auditor y an dvisua l discriminatio n learnin g i n shee p prenatall y an dpostnatall y expose dt o lead . Un

publishe dDoctora l Dissertation , Iow aStat e University . Ames , Iowa , 1976 . 303 . Bowman , R . an dP . Bushnell . Locomoto r activit y o f monkeys . In: Th e Effect s o f Lea dExposur e o n CN S Func

tion : A Worksho p o n Anima l Models . Sponsore db y th e U.S . Environmenta l Protectio n Agency . Hendersonville , Nort hCarolina , Octobe r 1976 . 304 . Brown , D . R . Neonata l lea dexposur e i n th e rat : Decrease dlearnin g a s afunctio n o f ag e an dbloo dlea d concentrations . Tox . an dAppl . Pharmacol . 52:628-637 , 1975 . 305 . Miller , E. , T . Sobotka , T . Michel , R . Levin , an dS . Krop . Neurotoxi c an dothe r

correlate s o f

earl y P b exposur e i n beagl e dogs . Proc . Fed . Am . Soc . Exper . Biol . 56(5):355 , 1977 . 306 . Hastings , L. , G . P . Cooper , R . L . Bornschein , an dI . A . Michaelson . Behaviora l effect s o f low-leve l neonata l lea d exposure . Pharmacol . Biochem . Behav . (I n Press) . 307 . Goiter , M . an dI . A . Michaelson . Growth , behavior , an d brai n catecholamine s i n lead-expose dneonata l rats : A reappraisal . Science . 787:359-361 , 1975 . 308 . Silbergeld , E . K . an dA . M . Goldberg . Pharmacologica l an dneuro-chemica l investigation s o f lead-induce dhy

peractivity . Neuropharmacol . 79:431-444 , 1975 . 309 . Silbergeld , E . K. , P . T . Carroll , an dA . M . Goldberg . Monoamine s i n lead-induce dhyperactivity . Pharmacol . 7 7:203 , 1975 . 310 . Grant , L . D. , G . Breese , J . L . Howard , M . R . Krigman , an dP . Mushak . Neurobiolog y o f lea dintoxicatio n i n th e developin g rat . Proc . Fed . Am . Soc . Exper . Biol . 55:503 , 1976 . 311 . Modak , A . T. , S . T . Weintraub , an dW . B . Stavinoha . Chroni c lea dingestio n an dth e cholinergi c nervou s system . Pharmacol . 77:204 , 1975 . 312 . Gerber,G . B. , A . Leonard , A . Mazanowska , J . Deroo , an d J . P . Decock . Biochemica l parameter s i n mic e give n differen t dose s o f

lea di n th e drinkin g water . Proc . Inter . Symposiu mEnvironmenta l Healt hAspect s o f Lead . 1972 . p . 232-238 . 313 . Hrdina , P . D. , D . A . V . Peters , an dR . L . Singhal . Effect s o f chroni c exposur e t o cadmium , lead , an dmercur y o n brai n biogeni c animal s i n th e rat . Res . Comm . Chem . Path . Pharmacol . 75:483-493 , 1976 . 314 . Michaelson , I . A . an dM . W . Sauerhoff . Anima l model s o f huma n disease : Sever e an dmil dlea dencephalopath y i n th e neonata l rat . Environ . Healt hPerspec . 7:201-225 , 1974 . 315 . Shih , T . M . an d1 . Hanin . Lea d(Pb ) exposur e decrease s acetylcholin e (Ach ) turnove r rat e (TOR ) i n ra t

brai n area s in vivo. Proc . Fed . Am . Soc . Exp . Biol . 56(3):3733A , 977 , 1977 . 316 . Carroll , P . T „ E . K . Silbergeld , an dA . M . Goldberg . Alteration s o f

centra l cholinergi c functio n b y lea dex posure . Biochem . Pharmacol . 26:397-402 , 1977 . 317 . Bhatnagar , S . P . Actio n o f som e centrall y actin g drug s an d heav y metal s o n in vitro oxidatio n o f dopamin e b y ra t brai n tissue . Can . J . Physiol . Pharmacol . 50:1080-1085 , 1972 . 318 . Brown , D . R. , A . W . Klein , an dR . T . Louis-Ferdinand . Effect s o f

lea do n behavioral , morphologica l an d biochemica l indice s o f developmen t

i n th e neonata l ra t brain . Soc . o f

Toxicol . Abst . 257:197 , 1976 . 319 . Silbergeld , E . K . an dJ . J . Chisholm . Lea dpoisoning : Altere durinar y catecholamin e metabolite s a s indicator s o f intoxicatio n i n mic e an dchildren . Science . 792:153-155 , 1976 . 11-6 2P. 7

320 . Holtzman , D . an dJ . She n Hsu . Earl y effect s o f inorgani c lea do n immatur e ra t brai n mitochondria l respiration . Pediatr . Res . 70:70-75 , 1976 . 321 . Wender , P . H. , R . S . Epstein , I . J . Copin , an dE . K . Gor

don . Urinar y monoamin e metabolite s i n childre n wit h brai n dysfunction . Am . J . Psychol . 27:147-151 , 1971 . 322 . Dugandzic , M. , B . Stankovic , L . Milovanic , an dZ . Kuricanac . Urinar y excretio n o f 5-hydroxyindoleaceti c aci di n lead-expose dperson s (Englis htitle) . Arh . Hig . Toksikol . 24(0:37-44 , 1973 . 323 . Nathanson , J . A . an dF . E . Bloom . Heav y metal s an d adenosin e cycli c 3' , 5 ' -monophosphat e metabolism : Possibl e relevanc e t o heav y meta l toxicity . Mol . Phar

macol . /2:390-398 , 1976 . 324 . Brierley , G . P . Effect s o f heav y metal s o n isolate d mitochondria . In: Biochemica l Effect s o f Environmenta l Pollutants . S . D . Le e (ed.) . An n Arbor , Mich. , An n Arbo r Sci . Publ . 1977 . p . 397-411 . 325 . Kostial , K . an dV . B . Vouk . Lea dion s an dsynapti c transmissio n i

n th e superio r

cervica l ganglio n o f

th e cat . Brit . J . Pharm . 72:219-222 , 1957 . 326 . Manalis , R . S . an dG . P . Cooper . Presynapti c an d postsynapti c effect s o f lea da t th e fro g neuromuscula r junction . Nature . 245:354-356 , 1973 . 327 . Cooper , G . P . an dR . S . Manalis . Effect s o f polyvalen t

cat ion s o n synapti c transmissio n i n fro g neuromuscula r junc

tio n an dfro g sympatheti c ganglion . In: Behaviora l Tox

icology . C . Xintaras , B . L . Johnson , an dI . DeGroo t (eds.) . U.S . Dept . o f

Health , Education , an dWelfare . U.S . Governmen t

Printin g Office , 1974 . 328 . Kober , T . E . an dG . P . Cooper . Lea dcompetitivel y in

hibit s calcium-dependen t synapti c transmissio n i n th e bullfro g sympatheti c ganglion . Nature . 262:704-705 , 1976 . 329 . Silbergeld , E . K. , J . T . Fales , an dA . M . Goldberg . Evi

denc e fo r

ajunctiona l effec t

o f lea do n neuromuscula r function . Nature . 247:49-50 , 1974 . 330 . Silbergeld , E . K. , J . T . Fales , an dA . M . Goldberg . Th e effect s o f

inorgani c lea do n th e neuromuscula r junction . Neuropharmacol . 75:795-801 , 1974 . 331 . Cooper , G . P . an dD . Steinberg . Effect s o f cadmiu man d lea do n adrenergi c neuromuscula r transmissio n i

n th e rab

bit . Am . J . Physiol . 252:C l 28-C 1 31 , 1977 . 332 . Oliver , T . Lea dpoisoning . London , H . K . Lewis . 1974 . 333 . Pejie , S . Lea dpoisoning . Ann . Intern . Med . 7:577 , 1928 . 334 . Wilson , V . K. , M . L . Thompson , an dC . E . Dent . Aminoaciduri ai

n lea dpoisoning . A cas e i n childhood . Lancet . 2:66-68 , 1953 . 335 . Marsden , H . B . an dV . K . Wilson . Susceptibilit y t o lea d toxicity . Brit . Med . J . 7:325 , 1955 . 336 . Clarkson , T . W . an dJ . E . Kench . Urinar y excretio n o f amin o acid s b y me n absorbin g heav y metals . Biochem . J . 62:361-372 . 337 . Cramer , K. , R . A . Goyer , R . Jagenburg , an dM . H . Wilson . Rena l ultrastructure , rena l function , an dparameter s o f lea dtoxicit y i n worker s wit hdifferen t period s o f

lea dex posure . Brit . J . Ind . Med , 57:113-127 , 1974 . 338 . Morris , C . E. , A . Heyman , an dT . Pocefsky . La y of f moonshine-i t

ma y contai n lead . JAMA . 784(8):40 , 1963 . 339 . Ball , D . E . an dD . Sorenson . Saturnin e gout~ A moonshin e malady . N . Eng . J . Med . 280:1238-1239 , 1969 . 340 . Lilis , P. , N . Gavrilescu , B . Nestorescu , C . Durimtiu , an d A . Roventa . Nephropath y i n chroni c lea dpoisoning . Brit . J . Ind . Med . 25: 196-202 , 1969 . 341 . Danilovic , V . Chroni c nephriti s du e t o ingestio n o f lead

contaminate dflour . Brit . Med . J . 7:27-28 , 1959 . 342 . Albahary , C , G . Richet , J . Guillaume , an dL . Morel

Maroger . L e rei n dan s l e saturnism e professionnel . Arch . Mal . Prof . 26:5-19 , 1965 . 343 . Wedeen , R . P. , J . K . Maesaka , B . Weiner , E . A . Lipat , M . M . Lyons , L . F . Vitale , an dM . M . Joselow . Occupationa l lea dnephropathy . Am . J . Med . 59:630-641 , 1975 . 344 . Nye , L . J . J . A n investigatio n o f th e extraordinar y inci

denc e o f chroni c nephriti s i n youn g peopl e i n Queensland . Med . J . Aust . 2:145-159 , 1929 . 345 . Henderson , D . A . an dJ . A . Inglis . Th e lea dconten t o f bon e i n chroni c Bright' s disease . Australas . Ann . Med . 6:145-154 , 1957 . 346 . Emmerson , B . T . Chroni c lea dnephropathy . Th e diag

nosti c us e o f

calciu mEDT A an dth e associatio n wit hgout . Australas . Ann . Med . 72:310-324 , 1963 . 347 . Chisholm , J . J. , Jr. , E . D . Mellits , an dM . B . Barrett . Inter

relationship s amon g bloo dlea dconcentration , quantita

tiv e dail y ALA- U an durinar y lea doutpu t followin g calciu mEDTA . In: G . F . Nordber g (ed.) . Effect s an d Dose-Respons e Relationship s o f Toxi c Metals . Amster

dam , Elsevie r

Scientifi c Publishin g Co . 1976 . p . 416-433 . 348 . Legge,T . M . Industria l lea dpoisoning . J . Hyg . 7:96 , 1901 . 349 . Tanssig , F . J . Abortion , spontaneou s an dinduced . St . Louis , Mosby . 1936 . p . Ill , 354 . 350 . Lane , R . E . Th e car e o f th e lea dworker . Brit . J . Ind . Med . 6:125-143 , 1949 . 351 . Nogaki , K . O n actio n o f lea do n bod y o f

lea drefiner y workers : Particularl y conception , pregnanc y an dparturi

tio n i n cas e o f

female s an dthei r

newborn . Excerp . Med . (XVII) . 4:2176 , 1958 . 352 . Fahim , M.S..Z . Fahim , an dD.G.Hall . Effect s o f subtox

ic lea dlevel s o n pregnan t wome n i n th e stat e o f

Missouri . Int' l Conf . o n Heav y Metal s i n th e Environment . Toronto , Ontario . Octobe r

27-31 , 1975 . 353 . Rom , W . N . Effect s o f lea do n th e femal e an dreproduc

tion : A review . Mt . Sina i J . Med . 45:542-552 , 1976 . 354 . Panova , A . Earl y change s i n th e ovaria n functio n o f wome n i n occupationa l contac t wit hinorgani c lead . In: Work s o f th e Unite dResearc hInstitut e o f Hygien e an dIn

dustria l Safety . Sofia , Bulgaria . 1972 . p . 161 . 355 . Zielhuis , R . L . an dA . A . E . Wibowo . Revie w paper : Susceptibilit y o f

adul t female s t o lead : Effect s o n reproductiv e functio n i n female s an dmales . 2n dInterna

tiona l Worksho p o n Permissibl e Limit s fo r Occupationa l Exposur e t o Lead . 1977 . (I n press) . 356 . Paul , C . Etud e su r I'intoxicatio n lent e pa r le s preparation s d e plomb ; deso n influenc e pa r l e produi t

d e laconception . Arch . Gen . Med . 75:513-533 , 1860 . 35*7 . Barltrop , D . Transfe r o f lea dt o th e huma n fetus . In: Minera l Metabolis mi n Paediatrics . D . Barltro p an dW . L . Burlan d(eds.) . Oxford , Blackwell . 1969 . p . 135-151 . 358 . Schroeder , H . A . an dI . H . Tipton . Th e huma n bod y burde n o f

lead . Arch . Environ . Health . 7 7:965-978 , 1968 . 359 . Wibberley , D . G. , A . K.Khera , J . H . Edwards , an dD . I . Rushton . Lea dlevel s i n huma n placenta e fro mnorma l an dmalforme dbirths . J . Med . Genetics . 74(4):l-7 , 1977 . 360 . Gershanik , J . J. , G . G . Brooks , an dJ . A . Little . Bloo dlea d value s i n pregnan t

wome n an dthei r

offspring . Amer . J . Obstet . Gynecol . 7 79:508-511 , 1974 . 361 . Gershanik , J . J. , G . G . Brooks , an dJ . A . Little . Feta l lea d value s i n arura l area . J . Pediatr . 84:112-113 , 1974 . 11-6 3P. 8

362 . Scanlon , J . Umbilica l cor d lea d concentration . Amer . J . Dis . Child . 727:325 , 1971 . 363 . Harris , P . an d M . R . Holley . Lea d level s i n cor d blood . Pediatr . 49:606-608 , 1972 . 364 . Haas , T. , A . B . Wieck , K . H . Schaller , K . Mache , an d H . Valentin . Di e usuell e Bleibelastun g be i Neugeborone n un d ihre n Muttern . Zentralbl . Bakteriol . Parasitenkd . In fektionskr . Hyg . Abt . l:Orig . Reih e B . 755:341-349 , 1972 . 365 . Fahim , M . S. , Z . Fahim , an d D . G . Hall . Effect s o f subtox i clea d level s o n pregnan t wome n i n th e stat e o f M issouri . Res . Comm . Chem . Pathol , an d Pharmacol . 75:309-330 , 1976 . 366 . Palmisano , P . A. , R . C . Sneed , an d G . Cassady . Untaxe d whiske yan d feta l lea d exposure . J . Pediatr . 75:869-872 , 1969 . 367 . Va n Assen , F . J . J . Ned . Pijdschr . Verloskd . Gynaecol . 58:258-263 , 1959 . 368 . Lancranjan , 1. , H . I . Popesca , O . Gavanescu , I . Klepsch , an d M . Serbanescr . Reproductiv e abilit yo f workme n oc cupationall yexpose d t o lead . Arch . Environ . Healt h 50:396-401 , 1975 . 369 . Stofen , D . Bleisal s Umweltgeft ; di e verdeckte n Bleivergiftung—e n Masse n phanomen ? Eshwege , Schroeder . 1974 . 370 . Schroeder , H . A . an d M . Mitchener . Toxi ceffect s o f trac e element s o n reproductio n o f mic e an d rats . Arch . Environ . Health . 25:102-106 , 1971 . 371 . Schroeder , H . A. , M . Mitchener , an d A . P . Nason . Zir conium , niobium , tin , vanadium , an d lea d i n rats : Life ter m studies . J . Nutri . 700:59-68 , 1970 . 372 . Morris , H . P. , E . P . Lang , H . J . Morri, , an d R . L . Grant . Th e growt h an d reproductio n o f rat s fe d diet s containin g lea d acetat e an d arseni ctrioxid e an d th e lea d arseni ccon ten t o f newbor n an d sucklin g rats . J . Pharm . Exp . Ther . 64:420 , 1938 . 373 . Stowe , H . D . an d R . A . Goyer . Th e reproductiv e abilit y an d progen yo f F l lea d toxi crats . Fertil . Steril . 22:755-760 , 1971 . 374 . Hilderbrand , D. , R . Der , W . Griffin , an d M . Fahim . Effec t o f lea d acetat e o n reproduction . Amer . J . Obst . Gynec . 755:1058-1065 , 1973 . 375 . Der , R. , Z . Fahim , an d D . Hilderbrand . Combine d effec t o f lea d an d lo wprotei n die t o n growth , sexua l develop ment , an d metabolis m i n femal e rats . Res . Commun . Chem . Pathol . Pharmacol . 9(4) : 723-738 , 1974 . 376 . Vermande-va n Eck , G . J . an d J . W . Meigs . Change s i n th e ovar yo f th e Rhesu s monke yafte rchroni clea d intoxica tion . Fertil . Steril . 77:223-234 , 1960 . 377 . Kennedy , G . L. , D . W . Arnold , an d J . C . Calandra . Teratogeni cevaluatio n o f lea d compound s i n mic e an d rats . Fd . Cosmet . Toxicol . 75:629-632 , 1975 . 378 . Hubermont , G. , J . P . Buchet , H . A . Roels , an d R . R . Lauwerys . Effec t o f short-ter m administratio n o f lea d t o pregnan t rats . Toxicol . 5:379 , 1976 . 379 . Maisin , J . R. , J . M . Jade , M . Lambiet-Collier . Progres s re por t o n morphologica l studie s o f th e toxi ceffect s o f lea d o n th e reproductiv e organ s an d th e embryos . Economi c Communit yo f Europ e Contrac t No . 080-74-7 , Env . B . Brussels , Belgium ; ECE . 1975 . 380 . Jacquet , P. , A . Leonard , an d G . B . Gerber . Progres s repor t o n studie s int o th e toxi cactio n o f lea d i n biochemistr yo f th e developin g brai n an d o n cytogenetic s o f pos t meioti c ger m cells . Economi cCommunit yo f Europ e Contrac t No . 037-038/74-7 , Env . B . Brussels , Belgium ; ECE . 1975 . 381 . Cole , L.J . an d L.J . Bachhuber . Effect s o f lea d o n th e ger m cell s o f th e mal e rabbi t an d fow l as indicate d b ythei rpro geny . Proc . Soc . Exp . Biol . Med . 72:24 , 1914 . 382 . Weller , C . V . Th e blastrophthori ceffec t o f chroni clea d poisoning . J . Med . Res . 55:271 , 1915 . 383 . Der , R. , Z . Fahim , M . Yousef , an d M . Fahim . Environ menta l interactio n o f lea d an d cadmiu m o n reproductio n an d metabolis m o f mal e rats . Res . Comm . Chem . Pathol . Pharmacol . 74:689-713 , 1976 . 384 . Verma , M . M. , Joshi , S . R. , an d A . O . Adeyemi . Mutagenicit yan d infertilit yfollowin g administratio n o f lea d sub-acetat e t o Swis s mal e mice . Experientia . 50(5):486-487 , 1974 . 385 . McClain , R . M . an d B . A . Becker . Teratogenicity , feta l toxicity , an d placenta l transfe ro f lea d nitrat e i n rats . Tox icol . Appl . Pharmacol . 5/:72-82 , 1975 . 386 . Ferm , V . H . an d S . J . Carpenter . Developmenta l malfor mation s resultin g fro m th e administratio n o f lea d salts . Exp . Mol . Pathol . 7:208-213 , 1967 . 387 . Ferm , V . H . an d D . W . Ferm . Th e specificit yo f th e teratogeni ceffect s o f lea d i n th e golde n hamster . Lif e Sci . 70:35-39 , 1967 . 388 . Vallee , B . L . an d D . D . Ulmer . Biochemica l effect s o f mer cury , cadmiu m an d lead . Ann . Rev . Biochem . 47:91-128 , 1972 . 389 . Ferm , V . H . Th e synteratogeni ceffec t o f lea d an d cad mium . Experientia . 25:56-57 , 1969 . 390 . Giliani , S . H . Congenita l cardia canomalie s i n lea d poisoning . Pathol . Microbiol . (Basel) . 59:85-90 , 1973 . 391 . Giliani , S . H . Congenita l anomalie s i n lea d poisoning . Obstet . Gynecol . 47:265-269 , 1973 . 392 . Millar , J . A „ V . Battistini , R . L . C . Cumming , F . Carswell , an d A . Goldberg . Lea d an d 8-amino-levulini caci d dehydratas e level s i n mentall yretarde d childre n an d i n lea d poisone d sucklin g rats . Lancet . 2:695 , 1970 . 393 . Porritt , N . Cumulativ e effect s o f infinitesima l dose s o f lead . Brit . Med . J , 2:92-94 , 1931 . 394 . Kremer , H . U . an d M . N . Frank . Coexistin g myxedem a an d chroni cplumbism . Ann . Intern . Med . 42:1130- 1 136 , 1955 . 395 . Monaenkova , A . M . Functiona l stat e o f th e thyroi d i n chroni cintoxicatio n wit h som e industria l poisons . Gig . Tr . Prof . Zabol . 7(2) : 44-48 , 1957 . 396 . Zel'tser , M . E . Th e functiona l stat e o f th e thyroi d glan d i n lea d poisoning . Tr . Inst . Kraevoi . Patol . Akad. , Nank , Ka z SSR . 70:116-120 , 1962 . 397 . Sandstead , H . H . an d R . Galloway . Effec t o f chroni clea d intoxicatio n o n in

vivo I" 1 uptak e b yth e ra t thyroid . Proc . Fed . Soc . Exp . Biol . Med . /24:l8-20 , 1967 . 398 . Sandstead , H . H. , E . G . Stant , A . B . Brill , L . 1 . Arias , an d R . T . Terry' . Lea d intoxicatio n an d th e thyroid . Arch . Int . Med . 725:632-635 , 1969 . 399 . Sandstead , H . H. , D . N . Orth , K . Abe , an d J . Stiel . Lea d in toxication : Effec t o n pituitar yan d adrena l functio n i n man . Clin . Res . 78:76 , 1970 . (Abstract) . 400 . Murashov , B . F . Functiona l stat e o f th e adrena l corte xi n chroni cpoisonin g wit h tetraethy l lead . Gig . Tr . Prof . Zabol . 70:46-47 , 1966 . 401 . Pines , A . G . Indexe s o f genera l reactivit yi n saturnin e tox icity . Vroch . Delo . 5:93-96 , 1965 . 402 . Makotchenko , V . M . Th e functiona l conditio n o f supr a rena l corte xi n chroni cpoisonin g wit h heav ymetal s (lead , mercury) . Tr . Ukr . Nauch . Issle d Inst . Eksp . Endoksinol . 20:162-170 , 1965 . 11-6 4P. 9

403 . Sandstead , H . H. , A . M . Michelakis , an dT . E . Temple . Lea dintoxication . It s effect s o n th e renin-aldosteras e respons e t o sodiu mdeprivation . Arch . Environ . Health . 20:356-363 , 1970 . 404 . Urbanowicz , H. , J . Grabecki , an dJ . Kozielska . Th e urin

ar y excretio n o f

5-hydroxyindoleaceti c aci di n industria l lea dexposure . Med . Lav . 60:582-586 , 1969 . 405 . Schiele , R. , K . H . Schalle , an dH . Valentin . Th e influenc e o f lea dupo n th e tryptopha n metabolism . Klin . Wschr . 52:401-404 , 1974 . 406 . Cooper , W . C , I . R . Tabershaw , an dK . W . Nelson . Laborator y studie s o f

worker s i n lea dsmeltin g an drefin

ing . In: Proc . o f

th e Int' l Symp. : Environmenta l Healt h Aspect s o f

Lead , Amsterdam , 2- 6 Octobe r 1972 . Luxem

bourg , Commissio n o f th e Europea n Communities , p . 517-529 , 1973 . 407 . Alvares , A . P. , S . Leigh , J . Conn , an dA . Kappas . Lea dan d methy l mercury : Effect s o f acut e exposur e o n cytochrom e P-45 0 an dmixe dfunctio n oxidas e syste mi n th e liver . J . Exptl . Med . 755:1406-1409 , 1972 . 408 . Remmer , H. , J . Schenkman , R . W . Estabrook , H . Sasame , J . Gillette , S . Narasimhulu , D . Y . Cooper , an dO . Ro

senthal . Dru g interactio n wit hhepati c microsoma l cytochrome . Mol . Pharmacol . 2:187 , 1966 . 409 . Scoppa , P. , M . Roumengous , an dW . Penning . Hepati c dru g metabolizin g activit y i n lead-poisone drats . Ex

perientia . 29:970-972 , 1973 . 410 . Alvares , A . P. , S . Kapelner , S . Sassa , an dA . Kappas . Dru g metabolis mi n norma l children , lead-poisone dchildren , an dnorma l adults . Clin . Pharmacol . Ther . 77:179-183 , 1975 . 411 . Alvares , A . P. , A . Fishbein , S . Sassa , K . E . Anderson , an d A . Kappas . Lea dintoxication : Effect s o n cytochrom e P-450-mediate dhepati c oxidations . Clin . Pharmacol . Ther . 19(2):]83-190 , 1976 . 412 . Tabershaw , I . R . an dW . C . Cooper . Healt hStud y o f Lea d Workers . A Repor t

Prepare dfo r

th e Internationa l Lea d an dZin c Organization . 1974 . 413 . Monaenkova , A . M . an dK . V . Glotova . Cardiovascula r change s i

n som e chroni c intoxication s wit hindustria l poison s (lead , carbo n disulphide , benzene) . Git . Tr . Prof . Zabol . 75(0:32-36 , 1969 . 414 . Vigdortchik , N . A . Lea dintoxicatio n i n th e etiolog y o f hy

pertonia . J . Ind . Hyg . 77:1-6 , 1935 . 415 . Cramer , K . an dL . Dahlberg . Incidenc e o f hypertensio n amon g lea dworkers . Brit . J . Ind . Med . 25:101-104 , 1966 . 416 . Dressen.W . C , T.J . Edwards , W.H . Reinhart , R . T . Page , S . H . Webster , D . W . Armstrong , an dR . R . Sayers . Th e contro l o f

lea dhazar di

n th e storag e batter y industry . Publ . Health . Bull . (Wash. ) No . 262 , 1941 . 417 . Scroczynski , J. , K . Zajusz , S . Kossmann , an dA . Wegill . • Effec t o f experimenta l lea dpoisonin g o n th e developmen t o f arteriosclerosis . Pol . Arch . Med . Wewn . 58:641-646 , 1967 . 418 . Prerovska , J . Einflus s vo n Ble i au f biochemisch e Veran

derunge n imSeru mun dVeranderunge n i n de r Aderwan t imHinblic k

au f Atherosklerose . in: Proc . o f th e Int' l Symp : Environmenta l Healt hAspect s o f Lead , Amster

dam , 2- 6 October , 1972 . Luxembourg , Commissio n o f th e Europea n Communities . 1973 . p . 551-558 . 419 . Myerson , R . M . an dJ . H . Eisenhauer . Atrioventricula r conductio n defect s i n lea dpoisoning . Am . J . Cardiol . 77:409-412 , 1963 . 420 . Freeman , Rreversibl e myocarditi s du e t o chroni c lea d poisonin g i n childhood . Arch . Dis . Child . 40:389-393 , 1965 . 421 . Silver , W . an dR . Rodriguez-Torres . Electrocardiographi c studie s i n childre n wit hlea dpoisoning . Pediatr . 47:1124-1127 , 1965 . 422 . Asokan , S . K. , C . A . Malpass , Jr. , an dF . T . Ulmer . Cir

culation . 44(Suppl . 2):101-104 , 1971 . 423 . Kosmider , S . an dT . Petelnz . Zin i n y elektrokar

diograficzn e u startazyc hoso b prezewelekly m aawodowy mzatrueie molowiem . Pol . Arch . Med . Wewn . 52:4.37-442 , 1962 . 424 . Makasev , K . K . an dL . V . Krovdina . Statu s o f th e in

terstitia l tissue s o f

vascula r

wall s an dthei r

penetratio n unde r lea dpoisoning . Tr . Nauen-issl . In-t aKraev . Pat . Kaz . SSR . 25:11-13 , 1972 . 425 . Mambeeva , A . A . an dI . D . Kobkova . Th e concentratio n o f catecholamine s i n tissue s o f th e cardiovascula r

syste m i n experimenta l lea dintoxication . Izv . Akad..Nau k Kazahst . SSR . Ser . Biol . 7:77-82 , 1969 . 426 . Hemphill , F. , M . L . Kaerberle , an dW . B . Buck . Lea dsup pressio n o f

mous e resistanc e t o Salmonella typhimurium. Science . /

72:1031-1032 , 1971 . 427 . Selye , H. , B . Tuckweber , an dL . Bertok . Effec t o f lea dace tat e o n th e susceptibilit y o f rat s t o bacteria l endotoxins . J . Bacteriol . 97:884-890 , 1966 . 428 . Gainer , J . H . Activatio n o f Rausche r

leukemi aviru s b y metals . J . Natl . Cance r Inst . 57:609-613 , 1973 . 429 . Gainer , J . H . Lea daggravate s vira l diseas e an drepresse s th e antivira l activit y o f interfero n inducers . Environ . Healt hPersp . Exp . lss . 7: 1 13-119 , 1974 . 430 . Williams , H . W. , W . T . Caraway , an dW . A . DeYoung . In

activatio n o f

antibodies : A causativ e facto r o f brai n patholog y i n acut e lea dintoxication . Arch . Neurol . Psy

chiat . 72:579-582 , 1954 . 431 . Koller , L . D . an dS . Kovacic . Decrease dantibod y forma

tio n i n mic e expose dt o lead . Nature . 250:148-150 , 1974 . 432 . Bingham , E. , E . A . Pfitzer , W . Barkley , an dE . P . Redford . Alveola r macrophages : Reduce dnumbe r i n rat s afte r prolonge dinhalatio n o f lea dsesquioxide . Science . 762:1297-1299 , 1968 . 433 . Bruch , T. , A . Brockhaus , an dW . Dehnen . In: Proceeding s o f th e Internationa l Symposium : Environmenta l Healt h Aspect s o f

Lead , Amsterdam , Octobe r 2-6 , 1972 . Luxem

bourg , Commissio n o f th e Europea n Communities , p . 221-230 . 434 . Reigart , J . R . an dC . D . Graber . Evaluatio n o f th e humora l immun e respons e o f childre n wit h lo w leve l ex posure . Bull . Environ . Contam . an dToxicol . 16: 1 12-117 , 1976 . 435 . Hicks , R . M . Air-born e lea da s a n environmenta l toxin . Chem-Biol . Interact . 5:361-390 , 1972 . 436 . Beritic , T . Lea dconcentratio n foun di n huma n bloo di n associatio n wit hlea dcolic . Arch . Environ . Health . 25:289-291 , 1971 .

11-6 5P.1 0



## 12 . ASSESSMEN T O F LEA D EXPOSURE S AN D ABSORPTIO N

I N HUMA N POPULATION S 1 2 1 INTRODUCTIO N Althoug hepidemiologica l studie s provid e th e mos t directl y relevan t

dat afo r

settin g ambien t

ai r qualit y standards , suc hinvestigation s ar e subjec t t o methodologica l an dpractica l difficulties . O f mos t interes t ar e studie s relatin g ambien t ai r lea dex posure s directl y t o huma n healt heffect s in variou s populatio n groups . Unfortunately , few suc hstudie s exist . Standard s setting , then , mus t rel y o n con structin g (1 ) th e linkag e betwee n exposure s t o en vironmenta l source s o f

lea dan dth e incorporatio n o f lea dfro mthos e source s in variou s segment s o f th e populatio n a s measure db y bloo dlea dlevel s an d(2 ) th e relationshi p betwee n level s o f lea di n th e bloo d an dassociate dhealt heffects . Thi s chapte r

wil l examin e th e detail s o f studyin g bloo dlea dlevel s i n huma n populations . Include d wil l b e a n examinatio n o f th e statistica l considera

tion s o f suc hinvestigation s a s wel l a s adiscussio n o f th e characteristic s o f

th e frequenc y distributio n o f bloo dlea dvalue s an do f ho w thes e ma y b e use da s tool s in settin g environmenta l standards . I n addi

tion , th e effect s o f

geographi c an ddemographi c variable s o n lea dburden s wil l b e considered , Finally , th e epidemiologica l an dclinica l studie s o n th e relationship s betwee n environmenta l lea dex posure s an dhuma n absorptio n wil l b e described , and , wher e available , quantitativ e estimate s o f thos e relationship s will b e presented . 12. 2 LEA D I N HUMA N POPULATION S I n thi s section , th e statistica l approache s fo r assessin g bloo dlea dlevel s in huma n population s wil l b e discussed , a s wil l thei r application s an dim

plications . Thi s discussio n will b e followe db y a descriptio n o f

finding s relatin g t o th e geographi c an ddemographi c distribution s o f bloo dlea dlevels . 12.2. 1 Statistica l Description s an d Implication s Man y survey s hav e describe dbloo dlea dvalue s i n huma n populations . No t unexpectedly , th e in

vestigators ' choice s o f

statistic s t o describ e centra l tendencie s an ddispersio n pattern s ar e no t uniform . Thi s lac k

o f uniformit y make s compariso n o f th e variou s studie s quit e difficult . Fo r example , centra l tendencie s ar e expresse da s eithe r arithmeti c o r geometri c means , an dth e measure s o f dispersio n als o vary . Ofte n th e arithmeti c mea n o f th e distribu

tio n i s muc hlarge r

tha n th e geometri c mean . 12.2.1. 1 FOR M O FTH E DISTRIBUTIO N O F BLOO D LEA D LEVEL S Severa l author s hav e eithe r suggeste do r

implie d tha t th e distributio n o f

bloo dlea dlevel s fo r an y relativel y homogeneou s populatio n closel y follow s a lognorma l distribution. 1 3 Lognormalit y ha s als o bee n note dfo r

othe r metals , suc ha s 90 S r

in bone s o f huma n populations. 4 Sne e ha s suggeste dtha t th e Pearso n syste mo f

curve s provide s aslightl y bette r fit fo r th e dat ao f

Aza r e t al . tha n th e lognormal, 5 bu t th e improvemen t

derive dfro mthi s syste mdoe s no t see msufficien t

t o warran t

th e us e o f

thi s little

know n technique . Yanke l e t al. 1 an dTeppe r

an d Levin 2 bot hfoun dthei r lea ddat at o b e lognormall y distributed . Furthe r

analysi s o f

th e Housto n stud y o f Johnso n e t

al., 6 th e Souther n Californi astud y o f Johnso n e t

al., 7 an dth e stud y o f Aza r e t al. 3 als o confirme dtha t

alognorma l distributio n provide da goo dfit t o th e data . Fo r

thes e reasons , muc ho f wha t i s presente din thi s chapte r i s base do n th e accep tanc e tha t

homogeneou s population s hav e alognor

ma l distributio n o f

bloo dlea dvalues . Th e lognorma l distributio n an dit s applicatio n t o biologica l measurement s ar e discusse db y severa l authors. 48

- 9 A variabl e i s sai dt o hav e alognorma l distributio n i

f th e logarith mo f

th e variable-i s nor mall y distributed . Becaus e o f th e skewe dnatur e o f th e lognorma l distribution , th e media n (50t hper centile ) i s amor e meaningfu l estimat e o f centra l ten denc y tha n th e arithmeti c mean . Fo r th e norma l dis

tribution , th e bes t

estimat e o f

th e media n i s X , th e simpl e arithmeti c mean . Forth e lognorma l distribu

tion , th e bes t

estimat e o f

th e media n i s th e geometri c mea n (GM) : 12- 1' *"*•*"" ' P.1 1

G M = Exp[ S (In(Xi))/n] . (12-1 )

i = 1 Th e standar ddeviatio n o f th e logarithm s is : S = [1 (ln(X;)

- ln(GM)) 2 /n-l]"2 . (12-2 ) i = 1 Th e geometri c standar ddeviation , als o know n a s th e standar dgeometri c deviation , i s give n by :

GS D = Exp(S) . If onl y th e arithmeti c mean , X , an darithmeti c stan dar ddeviation , SD , ar e given , the n th e geometri c mea n an dth e geometri c standar ddeviatio n ca n b e estimate dby: 1 0

G M = X/( l + SD 2 /X 2 )'' 2 (12-3 ) an d GS D Exp[(ln(SD 2 /X 2 + l))'/2] . (12-4 ) Th e geometri c standar ddeviatio n mus t b e in

terprete ddifferentl y tha n th e arithmeti c standar d deviation . Usin g th e SD , approximatel y 6 8 percen t o f th e populatio n wil l fal l betwee n (mea n - SD ) an d (mea n + SD) . Thes e sam e limit s fo r th e lognorma l distributio n becom e GM/GS D an d(GM)(GSD) . Fo r example , i

f apopulatio n ha s ageometri c mea n bloo dlea dleve l o f

2 0 withaGS D o f

1.3 , the n 9 5 percen t o f th e populatio n will hav e bloo dlea dlevel s betwee n 20/(1.3) ' % an d(20)(1.3)'- 9 6 o r 11.9 6 an d 33.45 . 12.2.1. 2 PERCENTIL E ESTIMATE S O FTH E LOGNORMA LDISTRIBUTIO N Fro mth e G M an dGSD , estimate s o f percentile s o f th e lognorma l distributio n ca n easil y b e obtaine d eithe r numericall y o r

graphically . Numerically , th e pthpercentile , X i s estimate db y

X p = (GM)(GSD) Z P(12-5 ) wher e z i s th e z valu e fro mastandar dnorma l table . Th e followin g value s ar e ofte n used : Percen t Percen t Percen t 1 2. 5 5 1 0 p -2.32 6 -1.96 0 -1.64 5 -1.28 2 2 5

5 0 7 5 9 0 p -.67 4 0.00 0 0.67 4 1.28 2 9 5 97. 5 9 9 99. 9 p

1.64 5 1.96 0 2.32 6 3.09 0 Anothe r metho do f

obtainin g percentil e estimate s i s agraphica l on e usin g lognorma l probabilit y paper . On e poin t

i s place dwher e th e geometri c mea n intersect s th e 50t hpercentile . A secon dpoin t i s place dwher e (GM ) (GSD) 2 32 6 intersect s th e 99t h percentile . A lin e draw n throug hthes e tw o point s give s th e estimate dcumulativ e frequenc y distribu

tion . Figur e 12-1 , fo r

example , i s draw n wit han assume dgeometri c standar ddeviatio n o f 1.3 .

Q 2 0 —

GM-GEOMETRI C MEA N GS D - GEOMETRI C STANDAR D DEVIATIO N Illl l ! I 1 I I I I 9 5 5 0 PERCEN TO F POPULATIO N WIT H BLOOD.LEA D LEVEL S

EXCEEDIN G GIVE N VALU E Figur e 12-1 . Estimate d cumulativ e distributio n o f bloo d lea d level s lo r population s i n whic h th e geometri c mea n leve l i s 15 , 25 , o r 4 0 M9/dl . Fro mthi s descriptio n o f th e distribution , esti

mate s ca n b e obtaine do f th e percentag e o f

bloo d lea dvalue s expecte dt o excee dan y give n leve l fo r an y give n geometri c mea n bloo dlea dlevel . Fo r ex ample , (Figur e 12-1 ) i n th e population s wit h geometri c mea n bloo dlea dlevel s o f 15 , 25 , an d4 0 Aig/d l whol e blood , 0.1 , 10 , an d6 8 percent , respec tively , wil l hav e bloo dlea dlevel s exceedin g 3 5 Mg/dl . A s state dabove , Figur e 12- 1 wa s draw n wit ha GS D o f 1.3 . Th e effec t

o f varyin g th e geometri c standar ddeviation s o n th e percentag e exceedin g a specifie dbloo dlea dvalu e i s show n in Figur e 12- 2 becaus e th e valu e o f

th e GS D ha s bee n show n t o var y acros s studie s (Tabl e 12-1) . A marke deffec t ca n be . noted . I t i s ver y important , therefore , t o b e sur e o f

10 0 8 0 ; I I 11Illll

^ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I 1 1 IK -

G M = GEOMETRI C MEA N — GS D • = GEOMETRI C STANDAR D DEVIATIO N — 1 MINI - O 1 0 S 8

PERCEN TO F POPULATIO N WIT H BLOOD-LEA D LEVEL S EXCEEDIN G GIVE N VALU E Figur e 12-2 . Estimate d cumulativ e distributio n o l bloo d lea d level s lo r population s havin g a geometri c mea n bloo d lea d leve l o f 2 5 Mg/dl , bu t geometri c standar d deviation s o l 1.2 , 1.3 , o r 1.5 . 12- 2P.1 2

th e valu e use dfo r

th e geometri c standar ddeviatio n i f th e lognorma l distributio n i s t o b e use din settin g environmenta l standards . Becaus e mos t

bloo dlea ddat ahav e bee n reporte d a s arithmeti c mean s an dstandar ddeviations , an d becaus e th e ra w dat aar e no t generall y available , thi s chapte r wil l us e th e ter m"mean " fo r arithmeti c mean . Th e arithmeti c standar ddeviations , whe n available , wil l b e identified . I f th e geometri c mean s ar e available , the y will b e reporte da s geometri c mean s withth e geometri c standar ddeviatio n pro vided . TABL E 12-1 . ANALYSI S O F VARIANC E FO R TH E LOGARITHM S O F BLOO D LEA D VALUE S FO R SELECTE D STUDIE S (Geometri c standar d deviation s give n i n parentheses )

Stud y Idaho ' Seve n Cit yStudy ? Souther n California-Males 7 Souther n California-Females 7 Houston 6 Azar 3 Populatio n siz e 87 9 190 8 64 107 189 149 Replicate s

pe r observatio n 3 1 2 2 2 2- 8 Numbe r

o l duplicate s 16 b 17 1 64 107 189 NA C Populatio n

variance 3 0.19 0 (1.55 ) 0.09 0 (1.35 ) 0.22 4 (1.60 ) 0.18 3 (1.53 ) 0.18 2 (1.53 ) 0.14 8 (1.47 ) Withi n grou p

variance 3 0.072 (1.31 ) 0.082 (1.33 ) 0.18 1 (1.53 ) 0.16 7 (1.51 ) 0.06 9 (1.30 ) 0.09 9 (1.37 ) Measuremen t

varianc e 0.01-2 " (1.12 ) 0.06 3 (1.28 ) 0.21 6 (1.59 ) 0.14 1 (1.45 ) 0.094 (1.36 ) 0.04 9 (1.25 )

a Include s measuremen t variation . D Base d o n a separat e Cente rfo rDiseas e Contro l versu s Idah o compariso n o f 1 6 sample s o f 1975 data , whic h ar e differen t fro m th e 1974 dat a fo rth e Idah o study. 1 Th e estimate s o f populatio n an d withi n grou p varianc e com e fro m th e origina l study . cNo t available . 12.2.1. 3 VARIATIO N I N BLOO D LEA D VALUE S Th e tota l variatio n i n bloo dlea dvalue s fo r an y stud y i s compose do f

thre e varianc e components : (1 ) betwee n group , (2 ) withi n grou p o r individual , an d (3 ) metho dvariation . Th e metho dvarianc e result s fro mbot hsamplin g an danalytica l measuremen t variations . Th e withi n grou p varianc e result s fro m th e differenc e i n biologica l respons e amon g in

dividual s wit hth e sam e exposur e a s wel l a s demographi c difference s i n age , sex , race , socioeconomi c status , an denvironmenta l back

groun do f

th e individual s in agroup . Th e withi n grou p varianc e i s ameasur e o f th e homogeneit y o f peopl e in agroup , bu t als o include s metho d variance . Th e betwee n grou p varianc e result s fro m th e difference s i n th e compositio n o f peopl e i n a group , suc ha s polic e officer s o r housewives . I n studyin g th e effec t

o f lea dexposur e o n bloo dlea d levels , i t i s necessar y t o separat e thes e source s o f variatio n t o kno w whethe r th e stud y result s ar e meaningful . I f

th e bloo dlea dsamplin g an danalysi s error s ar e large , an y effect s o f differen t

lea dex posur e ma y no t b e seen . I n asimila r

manner , if

th e grou p chose n fo r

astud y i s no t

homogeneous , th e withi n grou p varianc e ma y b e s o larg e tha t th e difference s i n bloo dlea dvalue s canno t b e inter

prete da s resultin g fro mexposure . Th e source s o f variatio n ar e estimate din Tabl e 12- 1 fo r severa l studie s fo r

whic hth e ra w dat awer e available . Th e variatio n i s expresse di n term s o f th e natura l logarithm s o f

th e bloo dlea dvalues , an dth e cal

culation s wer e mad e usin g standar danalysi s o f varianc e techniques . Th e variance s ar e converte dt o geometri c standar ddeviation s an dthes e value s ar e show n i n parentheses . Tabl e 12- 1 show s tha t

alarg e portio n o f

th e tota l variatio n i s cause db y measuremen t variation , ex cep t possibl y fo r

th e Idaho 1 study . Th e measuremen t variatio n wa s unusuall y larg e fo r th e Souther n Californi astudy, 7 suggestin g tha t result s fro mthi s stud y shoul db e viewe dwit hcaution . Excep t fo r th e Souther n Californi astudy , th e GS D fo r withi n grou p variatio n wa s consistentl y nea r 1.3 . Thi s numbe r

in

clude s bot hbiologi c an dmeasuremen t variation . I t i s possibl e fo r

th e measuremen t

variatio n t o excee d 12- 3P.1 3



### th e withi n grou p variatio n i f ther e i s more tha n on e readin g per

individual , however , a s wa s th e cas e i n bot hth e Souther

n Californi aandHousto n studies . 

### 12.2.1. 4 PROBLE M O F FALS E EXCEEDENCE S Lucas 1 1 

### ha s describe daproble mtha t he term s "fals e exceedences. " Fo r

example , alognormal dis

tributio n wit

hageometri c mea

n o f 2 5 an da geometri c standar ddeviatio n o f 1. 3 will hav e 3. 7 percen t o f th e distributio n abov e 40 . A s ahypotheti

ca l example , i

f hal f o f th e variatio n i s cause db y measuremen t

variation , the n th e "true " distributio n woul dhav e ageometri c standar ddeviatio n o f 1.2 andwoul dhav e only 0. 6 percent o f th e distributio n abov e 40 . Fals e exceedence s become areal proble mi f a threshol dvalue, suc

ha s 40 , i s determine dfro m source s o f dat alackin g alarg e measurementvariation . I n suc hcases , th e estimate dpercentag e o f th e distributio n abov e afixedlevel will b e a n over estimate a s shown i

n th e previou s paragraph . I t i s ex tremel y difficult

t o obtai n more accurat e estimate s becaus e th e appropriat e varianc e ca n only b e esti

mate dindirectl y andonly i n case s wher

e ther e ar e replicat e measurement s o n th e same individual . If , however , th e threshol ditsel f i s estimate dfro

mdat a havin g thi s same measurement variation , the n th e proble mi s more difficult . In suchcases , th e ob

serve dvariance s includin g measuremen t variatio n ma y b e more appropriate . A s th e technolog y o f measuremen t

improves , th e proble mwill become muchles s significant . 12.2. 2 Geographi c Variability in Huma n Bloo d Lea d Level s Numerou s studie s hav e been conducte dthrough

ou t th e worl destablishin g mea n bloo dleadcon centration s fo

r variou s remote , rural , suburban , an d urban populations . B

y examinin g th e difference s amon g th e observe dlevel s acros s thes e populations , inference s ca

n b e draw n concernin g th e ubiquit y o f leadexposure s a s well a s thei r relativ e magnitudes . A wor dof caution , however , mus t

b e inserte dhere . Man y o f thes e dat ahav e been collecte dover a perio do f tim e i n whichmeasuremen t

technolog y fo

r bloo dleaddetermination s ha s change dan dim

proved . Also , sometime s neither th e method s o

f analysi s no r

th e samplin g schem

e usedhav e been re ported . Studie s o f remot e population s hav e been use dt o estimate th e natura l backgroun dbloo dleadlevel fo r humans. 121 5 

### Likewise , studie s comparin g eithe r rura l o r suburban population s hav e bee n use dt o es tablis hth e effect of urban livin g o n bloo dlead levels . Al l thes e studies , however , ca n b e usedt o demonstrat e th e broa dvariety of population s i

n whichleadfro

mal l environmenta l source s ha s been foundi n people . Only afe w studies 121 5 

### hav e focuse don remot e populations . Goldwate r

andHoover 1 2 

### conducte da n internationa l study o

f urban an drura l population s i n whichinvestigator s fro m1 4 countrie s partici

pated ; only non-occupationall y expose dadult s wer e studied . On e laborator y di dal l th e chemica l analyses . Som

e o f thes e population s —Ne

w Guine a aborigines , fo

r exampl e —wer

e thought

t o b e remot e fro

mth e effects o

f industrialization . Th e mea n an dstandar ddeviation s o f bloo dleadfor

th e aborigines , however , wer e 2 2 an d5 /ug/dl , respec tively . Examinatio n o

f thei r livin g habit s coul dshe d no ligh t on th e source s o

f thi s lead . I

n contras t

t o this , urban resident s fro

mPer u i n th e sam e study ha d amea n o f 7 /ig/d l an dastandar ddeviatio n o f 5 Mg/dl . Stopps 13



### - 1 4 

### reporte ddat ao n remot e populations . Tabl e 12- 2 present s th e bloo dleadmean s a s rangin g fro m2 3 t o 12/ug/10 0 g . I n contras t

t o th e finding s o

f Goldwate r

an d Hoover 1 2 

### an dStopps, 131 4 

### Hecker e t al. 1 5 

### i n amore recen t study o f Amazo n Rive r

Basin Indians , using anodi c strippin g voltammetry , foundamea n bloo d leadof 0.8 3 figldl

wit hastandar ddeviatio n of

0.5 9 i n 9 0 subjects . Th e urinary level s were no t quit e a s lo w a s th e bloo dlead s (mean , 7. 9 /ug/dl ; SD , 5.7) , bu t stil l ar e low i

n compariso n wit

hth e value s re porte di n Goldwate r

an dHoover. 1 2 TABL E 12-2 . BLOO D LEA D LEVEL S O F REMOT E

POPULATIONS 13 - 1 4 Population s Brazilia n Indian s Marshal l Islander s Peruvia n Indian s Islander s of f Australi a Bushme n Ne wGuine a native s Eas t African s Sampl e siz e 1 1 3 3 3 9 2 8 6 8 6 7 6 3 Bloo d lead .

ug/10 0 g 2 3 2 3 1 8 17. 5 1 6 1 3 1 2 

### A number

o f studie s hav e specificall y contraste d bloo dleadresult s between rural , suburban , an dur ba n populations. 2162 1 

### Tw o o f th e methodologicall y bette r studie s ar e thos e o

f Teppe r an dLevin, 2 

### an d Nordman. 1 6 

### Teppe r

an dLevin 2 

### conducte dastudy of th e bloo dleadlevel s o

f 1 1 group s o

f housewive s fro m8 U.S . metropolita n areas . Thre e o f these , Chicago , Ne

w York , an dPhiladelphia , hadurban

12- 4P.1 4

subura n compariso n groups . Tabl e 12- 3 display s th e result s o f th e contrast s betwee n thos e group s a s cal

culate db y Hasselbla dan dNelson. 2 2 I n ever y case , a significan t

differenc e wa s obtained . TABL E 12-3 . AG E AN D SMOKING-ADJUSTE D GEOMETRI C MEA N BLOO D LEAD S I N URBA N VERSU S SUBURBA N

AREA S O F THRE E CITIE S

Cil y Chicago , I L Philadelphia , P

A Ne wYork . N Y Thre e citie s togethe r Urba n 17.5 5 20.1 2 16.4 7 18.0 5 Bloo d Lead , ug % Suburba n 14.02 17.8 8 15.2 4 15.7 1 Urba n exces s

3.5 3 2.2 4 1.2 3 2.34 Significan t

>0.0 1 >0.0 1 >0.0 1 >0.0 1 Nordman 1 6 studie daserie s o f population s i n Fin

lan dincludin g downtow n urban , suburban , an d rura l populations . N o statisticall y significan t difference s wer e observe dbetwee n urba n an drura l o r suburba n residents . But , interestingly , non e o f th e population s studied , whic hinclude dtraffi c police

men , streetsweepers , downtow n Helsink i residents , an drura l controls , ha damea n bloo dlea dleve l tha t exceede d13. 5 figldl. Othe r studie s permittin g urba n rura l comparison s includ e thos e o f

Hofreute r

e t al., 1 7 Creaso n e t

al., 1 8 Scanlon, 1 9 Gershani k

e t al., 2 0 an dCohe n e t

al. 2 1 Hofreute r

e t al., 1 7 in 1960 , collecte dbloo dsample s fro mabou t

12 0 peopl e in eac ho f 6 citie s an dfro m 16 2 peopl e i n arura l are a(centra l Ohio) . Tabl e 12- 4 display s th e result s o f

thes e comparisons . I n al l ur ba n surve y sites , th e mea n bloo dlea dleve l wa s sig

nificantl y highe r

tha n in th e rura l surve y sites . TABL E 12-4 . BLOO D LEA D CONCENTRATION S I N SI X URBA N AN D ON E RURA L POPULATIO N

Surve ysit e Ne wOrleans , L

A Chicago , I L Ne wYork , N Y Cincinnati , O H Dallas , T X Denver , C O Rura l No . o l sample s 130 9 7 11 2 137 12 8 13 1 16 2 Mea n

bloo d lead . jjg/100 g 2 2 2 0 2 0 2 0 1 8 1 9 1 4 Urba n

exces s 8 6 6 6 4 5 Creaso n e t

al. 1

- 8 studie dmilitar y recruit s i n th e Chicag o are aa t

th e tim e o f

thei r induction . B y th e ver y natur e o f

th e sample , onl y youn g mal e adult s wer e included . Further , analysi s wa s restricte dt o thos e havin g live da t

th e sam e hom e addres s fo r tw o o r mor e years . Th e populatio n wa s broke n dow n b y rac e an dthre e residentia l locations , namel y urban , suburban , an doutstate . Media n bloo dlevel s fo r white s wer e 22 , 20 , an d3 6 figldl fo r th e urban , suburban , an doutstat e populations , respectively .

Scanlon 1 9 reporte do n umbilica l cor dbloo dlea d level s fo r infant s bor n t o Bosto n are awomen . Mea n bloo dlea dlevel s fo r

urba n infant s wer e 22. 1 /ug/d l compare dwit h18. 3 /ug/d l fo r th e suburba n newborn . Thi s differenc e wa s no t statisticall y signifi

cant . Gershani k

e t al. 2 0 studyin g alarge r

sampl e o f

cor d blood s in Shreveport , Louisiana , however , foun da statisticall y significan t

differenc e betwee n urba n an d suburba n infan t

cor dbloo dlea dlevels , 9. 7 ± 3. 9 versu s 8. 3 ± 2. 4 /xg/dl , respectively . Cohe n e t

al. 2 1 reporte do n arural-urba n com pariso n fo r

children , age d1 t o 5 years , livin g in 2 rura l countie s an di n Hartford , Connecticut . Althoug hth e 2 sample s wer e adequatel y matche do n age , ther e wa s amajo r

racial/ethni c differenc e — th e urba n populatio n bein g eithe r blac k o r Puert o Rica n an dth e rura l primaril y white . Th e mea n an dstan dar ddeviatio n o f

th e bloo dlea dconcentration s wer e 32. 7 ± 14. 8 an d22. 8 ± 11. 0 fo r th e urba n an d rura l populations , respectively . Som e o f thes e sam e studies , a s wel l a s others , ca n b e use dt o discer n awide r pictur e o f

th e variabilit y o f bloo dlea dlevels. 12141 7 I n th e Goldwate r an d Hoove r study, 1 2 urba n populatio n mea n bloo dlea d level s wer e foun dt o rang e fro m7 t o 2 5 figld\, wherea s th e mea n fo r

rura l area s range dfro m9 t o 3 2 /xg/dl . Th e wid e rang e o f mean s i n bot hpopula

tio n type s suggest s tha t lea dca n b e foun di n man y locations . Nordman 1 6 reviewe dth e availabl e literatur e o n bloo dlea dlevel s an dconclude dtha t "th e Pb- B mea n value s fo r

occupationall y unexpose drura l an d urba n population s rang e fro m1 0 t o 2 6 /ug/dl. " Ex

ception s t o thi s genera l rang e ar e found , however . Lower-than-usua l bloo dlea dlevel s hav e bee n re porte dfro msom e part s o f Swede n an dFinland . There , level s in wome n wer e foun dt o b e 1 0 /ug/dl. 16

- 2 3 O n th e othe r hand , higher-than-usua l bloo dlea dvalue s hav e bee n reporte dfro msection s o f Ital y an dFrance. 242 7 Zurl o e t al., 2 4 i n particular , reporte dver y hig hbloo dlea dlevel s fo r adult s i n th e Mila n area , urba n mea n o f 3 0 /xg/d l fo r

male s an d 23. 7 figldl

fo r females . Dat aobtaine dfro madult s withi n th e Unite d State s follo w asimila r pattern. 2172 8 I n dat afro m Teppe r an dLevin, 2 difference s wer e note di n th e geometri c mea n bloo dlea damon g th e 1 1 popula

tion s o f housewive s studied . Th e lowes t bloo dlea d value s wer e foun di n Houston , Texas , wit haG M an daGS D o f

12. 5 an d1.31 , respectively , wherea s th e highes t

wer e foun din Rittenhouse , asectio n o f 12- 5P.1 5



### Philadelphi a—G M an dGS D o f 20. 6 an d1.33 , respectively . In th e 196 0 Hofreute r

e t al . study, 1 7 

### bloo dsam ple s wer e collecte dfro

mpeopl e i

n si x metropolita n area s an don e rura l contro l site . Th e mea n bloo d leadvalue s varie dfro

m1 4 t o 2 2 /ug/10 0 g . Th e max imu mobserve dvalue s range dfro m3 8 t o 6 0 Mg/10 0 g . Kubot ae t al. 2 8 

### studie dbloo dleadlevel s i n mal e resident s o

f 1 9 intermediate-size dcitie s acros s th e Unite dStates . Mea

n bloo dlevel s were foundt o vary fro m7.2 5 /ug/d

l i n Lafayette , Louisiana , t o 20.3 4 figldl i n Jacksonville , Florida . Th e highes t reporte d value, 109.2 7 /xg/dl , occurre di n Fargo , North Dakota . A wide rang e i

n value s wa s reporte dfo r eachcity , th e larges t

bein g 5.9 1 t o 109.2 7 /xg/d l i n Fargo . Further , th e author s report thre e citie s wit

h mea n bloo dleadlevel s belo w 8.0 0 /ug/dl , namel y Lubbock , Texas , 7.95 ; Geneva , Ne w York , 7.65 ; an dLafayette , Louisiana , 7.2 5 /xg/dl . Thes e low value s approximat e thos e foundi n part s o f Scan

dinavia. 1 6 

### Worker s a

t 2 3 DuPon t

Company plant s wer

e studie dover

a5-yea r period , 1967 throug h1971. 2 9 

### No time tren dwa s note dfor bloo dleadlevels , an d th e sample s wer

e poole dper

plan t fo r th e 5 years . Th e geometri c mea

n value s varie dfro

malow o

f 15. 5 /ug/10 0 g fo

r th e Ashland , Wisconsin , plan t t o a hig ho f 21. 6 /ug/100 g a

t th e Lo s Angeles , California , plant . Th e overal l geometri c mea n fo r th e 2 3 loca

tion s was 18. 2 /ug/10 0 g . Dat aaddressin g geographi c variatio n o f bloo d leadvalue s i

n childre n ar e no t

a s extensive . Fo r

th e Unite dStates , Fin e et

al., 3 0 

### Baker

e t al., 3 1 

### an d Joselo w e t al. 3 2 

### provide dth e bes t

availabl e infor

mation . Fin e e

t al. 3 0 

### studie d615 1 childre n age d1 t o 6 year s i n 1 4 intermediate-size dcitie s i n Illinoi s i

n 1971 . Bloo dleadvalue s (Tabl e 12-5 ) were deter

mine db y a n atomi c absorptio n technique . Mea n value s fo r citie s range dfro

m19. 8 t o 32. 9 figldl; th e mea n fo r al l 1 4 citie s was 25. 5 /ug/dl . Thes e value s ar e indicativ e o

f source s o f leadi n th e children' s en vironment . Baker et al. 3 1 

### determine dbloo dleadvalue s fo r 167 2 childre n age d1 t o 5 livin g i n 1 9 town s contain

ing smelter s an d3 contro l towns . Th e smelter com munitie s wer

e selecte dfo

r study becaus e they had not previousl y been subjec t

t o thoroug hinvestiga

tion . Bloo dleadvalue s wer e determine db

y a n atomi c absorptio n technique . Th e mea n bloo dleadlevel s fo

r th e leadan dcop per smelter town s di dno t

diffe r fro mthos e contro l towns , a s shown i

n Tabl e 12-6 . Th e childre n livin g TABL E 12-5 . MEA N BLOO D LEA D VALUE S FO R CHILDRE N I N 1 4 INTERMEDIATE-SIZE D CITIE S I N ILLINOIS , 1971 3 0

Cit y Auror a Springfiel d Peori a Eas t St . Loui s Decatu r Jolie t Roc k Islan d Eas t Molin e Harve yan d Phoeni x Eas t Chicag o Height s Chicag o Height s Robbin s Carbondal e Rockfor d Tota l No . O l childre n screene d 44 9 67 0 38 7 37 6 79 3 38 3 28 5 29 8 22 6 172 53 7 103 264 1,208 6,15 1 % o l city' s

childre n age s 1- 6 y r screene d 5.0 9 7.2 8 2.9 7 4.0 9 5.8 4 4.5 4 5.6 0 12.32 4.9 0 17.1 3 10.3 6 6.7 8 17.4 6 7.3 1 6.1 4 Mea n bloo d

lea d value , ug/d l 28. 2 31. 5 32. 9 28. 6 21. 5 27. 8 25. 0 23. 5 22. 6 27. 3 25. 2 22. 2 28. 5 19. 8 25. 5 

### i n zin c smelter

towns , however , showedsignificantly higher bloo dleadvalue s than th e othe r thre e groups . Th e lowes t

mea n bloo dleadvalue , 9.1 5 /ug/dl , was foundi n childre n fo

r McGill , Nevada , wherea s th e highes t mea n valu e was foundfo

r Bartlesville , Oklahoma, wit

h28.6 0 /ug/dl . Joselo w e t al. 3 2 

### compare dth e bloo dleadlevel s o f childre n aged3 t o 5 year s i n Newark , Ne

w Jersey , andHonolulu , Hawaii , i

n 1973 . Th e study include d 15 2 childre n who wer

e matche dfor

ag e an dse

x int o 2 group s o

f 7 6 fro meachcity . Th e mea

n bloo dlead valu e fo r th e Newar

k childre n wa s 2 8 /ug/dl , con siderabl y higher

than tha t

foun di

n Honolul u children , 1 7 /xg/dl . 12.2. 3 Demographi c Variable s an d Huma n Bloo d Lea d Level s Fewe r dat aar e availabl e t o evaluat e th e effect s o f age , sex , an drac e on bloo dleadlevels . Childre n consistentl y develo p higher bloo dlead level s than d o adult s i

n th e same environmenta l set ting . In E

l Paso , Texas, 3 3 

### i

n 1972 , 7 0 percent

o f childre n 1 t o 4 year s ol dlivin g nea r aprimary lead , copper , an dzin c smelter

hadbloo dleadlevel s >4 0 /xg/dl , an d1 4 percen t

exceede d6 0 /ug/dl . I n childre n 5 t o 9 year s old , 4 5 percen t exceede d4 0 figldl, a s di d3 1 percen t o f measurement s i

n in

dividual s 1 0 t o 1 9 year s ol dan d1 6 percen t of thos e over 19 . In th e vicinit

y o f aprimary leadsmelter

i n Idah o i n 1974 , th e geometri c mea n bloo dleadlevel s shown i n Tabl e 12- 2 wer

e obtained. 1 

### A s ca

n b e see n fro mTabl e 12-7 , childre n unde r 1 0 year s o

f ag e consistentl y hadhigher

bloo dleadvalue s than olde r childre n an dadult s withi n th e same environment . 12- 6P.1 6

TABL E 12-6 . BLOO D LEA D LEVEL S (WHOL E BLOOD ) I N CHILDRE N I N U.S . SMELTE R AN D COMPARISO N TOWNS , 1975 3 1

Cit y No . o l sample s Mea n SE a G M GS D Percen t exceedin g 35 ug/d l Compariso n town s Albuquerque , N M Perryville , M O Safford , A Z Tota l Lea d smelte rtown s Bixby , M O Glover , M O Herculaneum , M O Tota l Coppe rsmelte rtown s Ajo . AZ Anaconda , M T Coppe rHill , T N Douglas , AZ Hayden , A Z Hurley , M N McGill , N V Miami , A Z Morenci , A Z Sa n Manuel , AZ Whit e Pine . M l Tota l Zin csmelte rtown s Amarillo . T

X Bartlesville , O K Corpu s Christi . T

X Monaco , PA Palmerton , PA Tota l 8 1 8 5 9 2 25 8 4 8 2 3 8 7 15 8 10 5 6 4 8 6 9 7 10 0 4 2 5 0 9 4 10 0 10 1 7 0 90 9 8 4 8 7 1 2 6 2 10 2 34 7 17.7 0

16.8 8 15.2 6 16.5 6 13.7 6 12.0 5 18.8 0 16.3 4 12.5 5 13.3 8 16.6 3 20.4 7 21.2 4 14.3 3 9.1 5 17.0 0 13.8 7 18.0 1 18.6 2 16.3 6 22.3 4 28.6 0 19.0 2 14.8 4 17.5 1 21.0 4 0.6 3

0.7 4 0.7 1 0.4 1 0.9 6 1.1 9 0.9 4 0.6 6 0.4 6 0.9 5 0.7 4 0.8 6 0.8 5 1.2 3 0.5 2 0.7 4 0.5 6 0.5 5 0.7 4 0.2 5 1.1 6 1.9 1 1.4 2 0.8 2 0.6 0 0.6 6 16. 8

15. 8 13. 8 15. 4 12. 4 11. 1 17. 2 14. 6 11. 7 11. 6 15. 4 18. 9 19. 9 12. 8 8. 9 15. 5 12. 9 17. 2 17. 8 14. 8 20. 9 23. 6 18. 4 13. 7 16. 5 18. 6 1.3 9

1.4 2 1.5 7 1.5 7 1.6 6 1.5 8 1.5 4 1.6 4 1.4 5 1.7 7 1.4 7 1.4 9 1.4 2 1.6 0 1.4 5 1.5 9 1.4 7 1.3 7 1.3 4 1.5 8 1.4 1 1.9 2 1.3 2 1.4 9 1.4 2 1.6 3 0. 0

2. 4 1. 1 1. 2 0. 0 0. 0 8. 0 4. 4 0. 0 1. 6 1. 2 3. 1 5. 0 4. 8 0. 0 3. 2 0. 0 1. 0 2. 9 2. 0 4. 8 31. 0 0. 0 1. 6 1. 0 9. 5 S E = standar d error . TABL E 12-7 . GEOMETRI C MEA N AN D GEOMETRI C STANDAR D DEVIATION S (I N PARENTHESES ) O F BLOO D LEA D LEVEL S BY AG E AN D STUD Y SECTO R (-ug/dl ) Stud y secto r I I I II I <1 0 66(1.33 ) 47(1.30 ) 34(1.26 ) Age . year s 10-1 9 39(1.26 ) 33(1.23 ) 28(1.40 ) >2 0

38(1.32 ) 33(1.33 ) 30(1.35 ) Likewise , astud y o f

traffi c exposur e i n Dallas , Texas, 3 4 foun dmea n bloo dlea dconcentration s o f 1 2 t o 1 8 /xg/d l i n childre n a s contraste dwit h9 t o 1 4 figldl in adults , whe n exposur e level s ar e controlled . Simpso n e t

al. 3 5 summarize dth e result s o f 2 7 neighborhoo dscreenin g program s conducte d throughou t

th e Unite dState s i n th e sprin g an dsum me r o f 1971 . The y foun dtha t childre n les s tha n 3 year s o f ag e ha dalowe r

rat e o f elevate dbloo dlea d tha n childre n olde r

tha n 3 years . O f

thos e unde r

3 years , 25. 8 percen t

ha dvalue s o f

2 40. 0 /xg/dl , wherea s 31. 4 percen t

o f thos e 3 year s o f

ag e o r olde r ha dvalues240.0/xg/dl . Ela me t al. 3 6 studie dpediatri c patient s in a Chicag o outpatien t

service . Th e proportio n o f childre n (Tabl e 12-8 ) withbloo dlea dvalue s 2 5 0 figldl varie dwithage ; th e proportio n ove r 5 0 figldl peake da t

1 8 t o 3 0 month s o f

age . TABL E 12-8 . PROPORTIO N O F CHILDRE N WIT H BLOO D LEA D VALUE S BETWEE N 5 0 AN D 9 9 /xg/dl , B Y AGE ,

CHICAG01971-1975 3 6 Age . month s % Bloo d lea d 50lo99/jg/d l 6-1 7 18-3 0 31-4 2 43-5 2 55-6 6 2 4 4 0 1 6 1 2 7 A stud y o f

Philadelphi aghett o children 3 7 con ducte din 197 2 throug h197 3 provide s dat arelevan t t o th e relationshi p betwee n ag e an dbloo dlea dlevel . Th e stud y populatio n consiste do f 155 9 blac k childre n age d6 month s t o 1 8 year s o f age . Tabl e 12- 9 present s th e bloo dlea dlevel s b y age . I n bot h 12- 7P.1 7



### G6P D norma l an ddeficient children , th e bloo dlea

d patter n o f increas e an ddecreas e b y advancin g ag e pertains . Th e only increase , but asubstantial one , i s observe dbetween childre n les s than 1 yea r o f ag e andthos e 1 t o 3 year s old . Bloo dlea dlevel s decreas e i

n al l succeedin g ag e groups . Billic k e t al, 3 8 

### analyze ddat afro

mNe w Yor k Cit y leadscreenin g program s fro m197 0 throug h1976 . Th e dat ainclud e ag e i

n months , sex , race , residenc e expresse da s healt

hdistrict , screenin g information , TABL E 12-9 . MEA N BLOO D LEA D (/xg% ) B Y AGE , SEX , AN D G6P D STATU S I N 155 9 URBA N BLAC KCHILDREN 3 7 Age , year s Sex Numbe r G6P D norma l G6P D deficien t < 1 1- 3 4- 8 9-1 3 14-1 8 Bot h

Male s Female s Bot h Male s Female s Bot h Male s Female s Bot h Male s Female s Bot h Male s Female s 6 1 32 2 9 28 9 133 156 40 4 17 7 22 7 39 4 18 9 20 5 242 9 4 14 8 19. 1 ±

19. 5 ± 19. 2 + 29. 1 ± 30. 5 ± 28. 8 ± 25. 0 ± 24. 6 ± 25. 1 ± 21. 3 ± 20. 4 ± 21. 7 ± 18. 7 ± 18. 5 ± 18. 8 ± 9. 5 9. 0 9. 2 14. 6 15. 1 11. 0 12. 6 13. 2 11. 1 10. 4 10. 9 9. 7 9. 7 10. 1 8. 9 9

6 3 4 0 3 0 1 0 5 5 3 8 1 7 44 2 9 1 5 2 1 1 3 8 18. 3 ±8. 2

18. 8 ±8. 2 17. 3 ±8. 4 33. 2 ±15. 5 33. 1 ±15. 5 33. 6 ±13. 5 25. 7 ±13. 4 25. 2 ±12. 9 26. 1 ±13. 5 23. 0 ±12. 5 22. 1 ±11. 8 24. 8 ±13. 9 19. 1 ±9. 9 18. 9 ±9. 3 19. 5 ±10. 1 

### an dbloo dleadvalue s expresse di n decades . Only th e firs t screenin g dat afo

r individual childre n wer

e include dbase do

n th e analysi s o

f venou s blood . Only th e dat a(178,58 8 values ) clearl y identifie da s comin g fro

mth e firs t

screenin g o

f agiven chil dwer

e used . Al l bloo dlea

ddetermination s wer

e don e b y th e sam e laboratory . Th e dat apresente dar e preliminary an da

n exhaustiv e analysi s ha s no t been completed . Tabl e 12-1 0 present s th e geometri c mean s fo r th e children' s bloo dleadlevel s b y ag e an d TABL E 12-10 . GEOMETRI C MEA N BLOO D LEA D LEVEL S I N NE W YOR KCITY LEA D SCREENIN G PROGRA M (Calculate d o n th e basi s o f th e Billic k

e t al. 3 8 data ) Grou p an d yea r Black s 197 0 197 1 1972 1973 197 4 197 5 1976 Hispani c 1970 197 1 1972 1973 197 4 197 5 1976 White s 1970 197 1 197 2 197 3 1974 197 5 1976 1-1 2

27. 2 25. 2 22. 3 22. 6 22. 2 20. 5 18. 1 21. 5 19. 9 18. 7 20. 1 19. 7 17. 4 17. 9 21. 0 19. 9 17. 1 20. 3 18. 6 19. 1 20. 7 13-2 4

31. 2 29. 7 26. 3 26. 9 25. 7 22. 9 20. 7 24. 9 22. 9 20. 6 21. 8 21. 4 19. 6 18. 6 23. 9 22. 8 20. 2 21. 5 20. 5 20. 0 17. 2 25-3 6

31. 2 30. 4 26. 7 26. 3 25. 5 22. 9 21. 2 25. 5 25. 0 22. 1 22. 5 23. 0 20. 6 19. 2 24. 7 22. 9 22. 0 21. 9 20. 0 19. 0 19. 1 Age . month s

37-4 8 28. 4 29. 8 25. 8 25. 6 24. 4 22. 3 20. 9 23. 9 24. 9 22. 6 23. 1 22. 6 20. 9 19. 3 25. 0 23. 0 21. 1 22. 1 21. 1 18. 2 18. 7 49-6 0

31. 4 28. 7 25. 0 24. 5 23. 7 21. 7 20. 3 24. 1 24. 4 22. 1 22. 2 22. 1 20. 6 19. 2 23. 7 23. 9 21. 2 20. 6 21. 4 19. 8 18. 4 61-7 2

22. 9 27. 7 24. 3 24. 1 22. 2 21. 8 19. 2 24. 5 23. 9 22. 0 21. 6 20. 1 20. 0 18. 2 24. 9 21. 9 21. 4 21. 6 21. 3 18. 0 17. 7 73 ^

25. 7 27. 0 23. 8 23. 1 22. 1 19. 6 19. 3 24. 0 23. 9 21. 3 21. 7 20. 3 18. 5 18. 4 22. 5 21. 7 20. 6 21. 1 19. 6 17. 3 17. 5 

### 12- 8P.1 8



### rac e fo r th e 7 years . It

shoul db e mentione dtha t th e mean s presente dwere derive db y EP A fromth e ra

w dat aprovide db

y Billic k et al. 3 8 

### Becaus e th e bloo d leadlevel s were availabl e t o th e neares t 1 0 /xg/dl , th e midpoint s of

eac hinterva l were use dt o calculat e th e geometri c means . Thes e mean s wer e calculate d fo r each2-mont

hinterval fo

r eac hag e an dethni c grou p an dwere then combine dacros s th e si x 2

- mont h interval s using a

n unweighte dgeometri c mea n s o a s t o minimiz e an

y seasonal effects . It shoul db e note dthat

al l racial/ethni c group s show a n increas e i

n geometri c mea

n level s fro

m< 1 t o 1 t o 2 year s o

f age . Figur e 12- 3 show s th e trend s fo r 1970 . Simila

r pattern s hol dfo

r othe r years . Th e 1

i

- Illl l

/ BLAC K

/ HISPANI C "*• —. . / ^^

\ / WHIT E ^ v Illl l ^

- T

AGE , year s Figur e 12-3 . Geometri c mean s fo r bloo d lea d value s by rac e an d age , NewYor k

City , 1971 . 

### difference s in age-associate dpattern s for th e thre e racial/ethni c group s ma

y b e influence db

y th e sub

stantia l difference s i

n populatio n size s fo

r th e groups : white s were th e smalles t group , Hispanic s wer e next , an dblack s th e largest . Tabl e 12-1 1 show s th e siz e o f th e group s fo

r th e 7 years . TABL E 12-11 . NUMBE R O F CHILDREN' S INITIA L SCREEN S I N NE W YOR KCIT Y PROGRAM S B Y RACE/ETHNICIT Y AN D

YEAR , 1970-19773 * Yea rWhit e Blac k Hispani c 197 0 197 1 197 2 197 3 197 4 197 5 197 6 1,28 2

2,79 6 1,35 0 82 3 60 1 65 6 49 1 8,83 9

23,17 4 16,73 0 9,72 2 4,13 9 4,58 5 3,75 5 8,25 1

18,74 0 10,15 3 6,87 5 2,49 8 2,62 0 2,17 8 

### age s 8 day s t o 8 year s showe dincreasin g mea n bloo d leadlevel s wit

hage : 3. 3 ± 2. 6 figldl

i n th e first yea r o f life , increasin g wit

heachyea

r t o amea n o f 11. 5 ± 4. 9 figldl a t ag e 6 t o 8 . I n contras t t o studie s o

f children , mos t

studie s o f adul t population s d o no t

show any marke deffect

o f agin g o n bloo dlea

dlevels . 17



### . 4 

### 0- 4 

### ' Nordman found that male s an dfemale s over

th e ag e o f 6 5 year s had lowe r bloo dleadvalue s than th e res t o f th e adul t populatio n i

n hi s study. 1 6 

### Effects o f se x on bloo dleadlevel s appear t o b e ag e dependent . Adul t

female s ar e commonl y foun d t o hav e lower

level s than males.2,16,17,23,2 4 Amon g children , however , se

x doe s no t

appear t o b e a differentiatin g factor. 424 3 

### Teppe r an dLevin 2 

### hav e suggeste dthat

th e difference s foundi

n bloo dlead level s o f adul t me n an dwome

n ar e no t th e resul t

o f eithe r difference s i

n leadintak e fromfoo do r from difference s i

n hematocri t

level s between them . Dat afor th e assessment

of rac e a s afacto r

i n bloo d leadlevel s ar e relativel y scarce . 18.25,38,44,4 5 Th e earlie r studies 184 4 

### repor t

onl y th e numbe r

o f case s abov e aspecifie dbloo dleadlevel . On e study 1 8 

### show s higher

leadlevel s for

black s tha n Puert o Ricans , bu t

th e other 4 4 

### report s tha t

black s hadhigh

er level s than nonblacks . In thei r study o f military recruits , Creaso n e t al. 1 8 

### compare dwhite an dblac k subjects . Dat ai

n Tabl e 12-1 2 show higher

mea n value s fo

r al l blac k group s than fo r th e whites . TABL E 12-12 . BLOO D LEA D LEVEL S (/ug/dl) 1 8 I N MILITAR Y

RECRUITS , BY RAC E AN D PLAC E

Plac e Numbe r Urba n 5 8 Suburba n 4 Outstat e 1 5 Mea n

3 8 8 0 5 9 90t h percentil e 8 5 124 105 Numbe r

20 3 21 8 40 6 Mea n

3 1 2 7 3 9 90t h percentil e 6 9 5 4 7 1



### I t i s o f interes t t o not e that

th e age-associate dpat tern observe di

n th e Unite dState s wa s no t see n i n a Wes t German 3 9 

### study . In tha t

study , 36 3 childre n o

f Th e Billic k

e t al. 3 8 

### dat ashow higher

geometri c mean bloo dlea dvalue s fo r black s tha n fo r Hispanic s o r

fo r whites . Tabl e 12-1 3 present s thes e geometri c mean s fo

r th e thre e racial/ethni c group s fo r 7 years . Th e consistenc y o f th e associatio n i s remarkable . Numerou s dat ahav e been publishe dshowin g th e effec t o f variou s occupation s o n bloo dlea d levels. 1625404 6 

### In general , thes e dat asupport th e conclusio n that

worker s expose dt o automobil e ex haust , leadfumes , o r

dus t i n manufacturin g carry higher leadburden s than thos e wh o d o not . 12- 9P.1 9

TABL E 12-13 . GEOMETRI C MEA N BLOO D LEA D LEVEL S ( M g/dl ) I N NE W YOR K LEA D SCREENIN G PROGRAM , 1970-1976 , FO R CHILDRE N U P T O 7 2 MONTH S O F AGE , B Y

RAC E AN D YEAR " Yea r 1970 197 1 197 2 197 3 197 4 197 5 197 6 Blac k

28. 6 28. 5 25. 0 25. 0 23. 9 22. 0 20. 0 Hispani c

24. 0 23. 4 21. 3 21. 9 21. 6 19. 8 18. 7 Whil e

23. 8 22. 4 20. 4 21. 3 20. 8 19. 0 18. 6 12. 3 RELATIONSHIP S BETWEE N EXTER NA L EXPOSURE S AN D BLOO D LEA D LEVEL S I n previou s chapters , it ha s bee n show n tha t

lead : 1 . I s emitte dfro mvariou s sources , primaril y automobile s an dindustria l operations . 2 . I s distribute dacros s th e environment . 3 . I s capabl e o f

bein g absorbe dint o th e huma n body . Thi s sectio n wil l describ e th e relationship s observe d betwee n th e differen t

environmenta l exposure s an d th e resultin g absorptio n a s measure db y bloo dlea d levels . Lea dtha t

i s emitte dfro mmobil e sources , e.g . au tomobil e exhausts , an dfro mstationar y sources , e.g . industria l operations , eithe r remain s in th e ai r

o r fall s out , a s discusse din Chapte r 6 . Studie s hav e show n abuildu p o f

lea di n soi l an ddus t

a s aresul t

o f emission s fro mthes e tw o sources . Further , th e lea d i n soi l an ddus t

doe s no t

deriv e onl y fro mthes e source s but , i n addition , fro mth e deterioratio n an d erosio n o f

lea dbase dpaint . Therefore , althoug hsoi l an ddus t ar e direc t

source s o f

huma n exposur e t o lead , the y mus t

als o b e viewe din term s o f th e pri

mar y mobil e an dstationar y source s o f th e lead . Consequently , studie s tha t examin e onl y ambien t

ai r lea dexposure s may , in fact , underestimat e th e tota l contributio n o f

airborn e lea dt o th e population' s lea dburden . Effort s t o estimat e experimentall y th e relativ e im

portanc e o f

combustio n o f

leade dgasolin e t o tota l lea dburde n i n human s hav e onl y recentl y bee n initi

ated . Manto n ha s presente devidenc e fro ma preliminar y stud y usin g lea disotop e ratios. 4 7 Hi s findings sugges t

tha t automobile s supplie dbetwee n 7 ± 3 an d4 1 ± 3 percen t o f th e lea di n bloo do f Dalla s resident s durin g 197 2 t o 1973 . Garibald i e t al., 4 8 i n amajo r

stud y bein g conducte di n Italy , ar e attemptin g suc hallocation s o n amuc hlarge r scale . I t i s hope dtha t

thes e dat awil l b e availabl e shortly . Becaus e multipl e source s o f lea dd o exis t

an d becaus e eac hca n contribut e t o th e tota l lea dburde n o f man , a n importan t

questio n t o b e addresse di s th e contributio n o f

eac hsourc e t o th e tota l bod y burden . I n thi s section , individua l studie s examinin g th e con tributio n fro mth e majo r environmenta l source s o f lead , tha t

is , air , soil-dust , paint , food , an dwater , will b e discussed . 12.3. 1 Ai rExposure s Studie s o f

th e relationshi p o f

ai r exposure s t o bloo dlea dlevel s ma y b e separate dint o tw o mai n categories : epidemiologica l an dclinical . Epidemiologica l studie s in tur n ma y b e groupe d int o thre e types : thos e pertainin g t o population s ex pose dt o mobil e source s o f emission , thos e o f population s expose dt o stationar y sources , an dthos e i n whic honl y th e amoun t o f airborn e lea di s take n int o accoun t

wit hn o effort

mad e t o identif

y th e source . Studie s dealin g wit hmobil e source s o f lea dwil l b e discusse dfirst , followe db y apresentatio n o f station

ar y source s studies . Studie s concerne dwit hai r lea d level s regardles s o f

source s wil l the n follow , an d clinica l studie s wil l complet e th e presentation . Fro m thi s array , th e studie s tha t permi t th e calculatio n o f th e quantitativ e relationshi p betwee n lea di n ai r an d lea di n bloo dwil l b e selectivel y analyze dan ddis

cussed . Clinica l studie s hav e th e advantag e o f permittin g precis e contro l ove r

th e level s o f

exposur e bu t

hav e th e disadvantage s o f

studyin g peopl e unde r some wha t artifica l condition s an do f dealing , b y necessity , wit hver y few subjects . Al l clinica l studie s t o b e presente dwer e limite dt o adults . Epidemiologica l studie s hav e th e advantag e o f studyin g peopl e i n thei r natura l state , bu t

frequentl y hav e th e disadvantag e o f rathe r imprecis e estimate s o f th e exposure s encountered . Thes e studie s allo w estimate s o f

th e relationshi p t o b e mad e fo r bot h adult s an dchildren . 12.3.1. 1 MOBIL E SOURC E STUDIE S 12.3.1.1. 1 Studie s i n th e Unite dStates . A 197 3 Housto n stud y examine dth e bloo dlea dlevel s o f parkin g garag e attendants , traffi c policemen , an d adul t female s livin g nea r

freeways. 6 A contro l grou p fo r eac ho f

th e thre e expose dpopulation s wa s selecte db y matchin g fo r age , education , an drace . Unfortunately , th e matchin g wa s no t altogethe r

suc cessful ; traffi c policeme n ha dles s educatio n tha n thei r control s an dth e garag e employee s wer e younge r tha n thei r

controls . Female s wer e matche d 12-1 0P.2 0

adequately , however . Th e finding s fo r th e si x group s studie dar e presente din Tabl e 12-14 . I t shoul db e note dtha t

th e mea n bloo dlea dvalue s fo r traffi c policeme n an dparkin g garag e attendants , tw o group s regularl y expose dt o highe r concentration s o f automotiv e exhausts , wer e significantl y highe r tha n th e mean s fo r

thei r relevan t

contro l groups . Statisticall y significan t

difference s i

n mea n value s wer e no t found , however , betwee n wome n livin g nea r afreewa y an dcontro l wome n livin g at greate r distance s fro mth e freeway . TABL E 12-14 . MEA N BLOO D LEA D LEVEL S FO R STUD Y AN D

CONTRO L GROUPS , HOUSTON ^ Grou p Policeme n Control s Garag e attendant s Control s Wome n livin g nea rfreewa y Control s Mean . jjg'd l 23. 1 18. 4 28. 3 21. 3 12. 9 11. 9 S D

9.2 1 7.3 8 10.3 3 9.7 0 4.4 7 4.2 8 Sampl e

siz e 14 1 15 0 11 9 9 5 12 0 11 7 P = 0.0 5

P= 0.0 5

P > 0.0 5 A Californi astudy 7

- 4 9 examine dbloo dlea dlevel s i n relatio n t o exposur e fro mautomotiv e lea di n tw o communities , Lo s Angele s an dLancaste r ( acity representativ e o f

th e hig hdesert) . Lo s Angele s resi

dent s studie dwer e individual s livin g in th e vicinit y o f heavil y travele dfreeway s withi n th e city . The y in

clude dmale s an dfemales , age d1 throug h16 , 1 7 throug h34 , an d3 5 an dover . Th e person s selecte d fro mLancaste r

represente dsimila r

ag e an dse x dis

tributions . O n tw o consecutiv e days , blood , urine , an dfece s sample s wer e collected . Ai r sample s wer e collecte dfro mon e Hi-Vo l sample r i n Lo s Angeles , locate dnea r

afreeway , an dtw o suc hsampler s i n Lancaster . Th e Lo s Angele s sample r collecte dfo r

7 days ; th e 2 in Lancaste r wer e utilize dfo r

1 4 days . O n th e firs t

da y o f ai r sampling , soi l sample s wer e collecte din eac hare ain th e vicinit y o f stud y sub

jects . Lea din ambien t

ai r alon g th e Lo s Angele s free

wa y average d6. 3 ± 0.7 1 /xg/m 3 , an din th e Lan

caste r are ath e averag e wa s 0. 6 ± 0.2 1 /ig/m 3

. Th e mea n soi l lea din Lo s Angele s wa s 363 3 figlg, wherea s tha t

foun di n Lancaste r

wa s 66. 9 figlg. Highe r concentration s o f

lea dwer e foun di n th e bloo do f children , a s wel l a s younge r an dolde r adult s livin g nea r

th e freeway , tha n i n individual s livin g i n th e contro l area . Tabl e 12-1 5 show s th e mea n bloo dlea dvalue s fo r th e si x groups . Difference s betwee n Lo s Angele s an dLancaste r group s wer e significan t

withth e sol e exceptio n o f th e olde r males . TABL E 12-15 . ARITHMETI C AN D GEOMETRI C MEA N BLOO D LEA D LEVEL S (Mg/dl )

FO R LO S ANGELE S AN D LANCASTER , CA , B Y SE X AN D AGE 7

Group s byse x an d age . year s Tota l Male s 1-1 6 17-3 4 35 - Female s 1-1 6 17-3 4 35 - N 12 6 5 6 2 0 2 9 7 7 0 1 8 4 1 1 1 Lo s Angele s

Mea n 16. 4 19. 3 23. 5 16. 6 18. 5 14. 2 16. 7 12. 9 14. 7 SE a

0. 7 1. 1 2. 5 1. 1 2. 0 0. 7 1. 8 0. 6 1. 5 Geometri c

mea n 14. 6 17. 2 20. 8 15. 1 17. 1 12. 8 14. 9 11. 8 13. 4 N

11 9 5 0 2 1 1 8 1 1 6 9 2 5 1 6 2 8 Lancaste r

Mea n 10. 5 11. 8 11. 1 11. 8 13. 0 9. 6 10. 2 9. 1 9. 3 S E

0. 4 0. 6 0. 8 0. 9 2. 0 0. 4 0. 7 1. 2 0. 5 Geometri c

mea n 9. 6 10. 8 10. 4 10. 9 11. 1 8. 8 9. 6 8. 0 8. 7 Significanc e

o f differenc e P b «.00 1 «.00 1 «00 1 .00 3 .0 9 «00 1 •C00 1 <00 1 <00 1

a Standar d error . b I test . I t ha s bee n pointe dou t

b y Sne e that , in th e high

traffic-densit y area , th e reporte d2 9 percen t o f sam ple s i n childre n 1 throug h1 6 year s ol dexceedin g 4 0 figldl represente d5 individuals. 5 0 Fo r 3 o f thes e a secon dbloo dsampl e showe dapproximatel y 2 0 figldl; asecon dsampl e wa s no t collecte dfro mth e othe r 2 . Th e disparit y betwee n bloo dsample s take n o n consecutiv e day s fro mchildre n i n th e stud y call s int o questio n th e validit y o f usin g thes e value s t o quantif y th e ai r lea dt o bloo dlea drelationship . Th e difference s betwee n sample s fo r adults , althoug h somewha t

large r tha n thos e foun din othe r studies , appea r acceptabl e fo r

us e i n calculations , however . A stud y o f

th e effect s o f

lower-leve l urba n traffi c densitie s o n bloo dlea dlevel s wa s undertake n i n Dallas , Tex. , i n 1976. 3 4 Th e stud y consiste do f tw o phases . On e phas e measure dair-lea dvalue s fo r selecte dtraffi c densitie s an dconditions , rangin g 12-1 1P.2 1

fro m^.1,00 0 t o abou t

37,00 0 cars/day . Th e secon d phas e consiste do f

a n epidemiologica l stud y o f traffi c densit y an dbloo dlea dlevel s amon g resi

dents . Figur e 12- 4 show s th e relationshi p betwee n arithmeti c mean s o f

ai r lea dan dtraffi c density . A s ca n b e see n fro mth e graph , areasonabl e fi t i s shown . TABL E 12-17 . SOI L LEA D LEVEL S BY TRAFFI C DENSITY "

-

- o •r- " D I

O

I o I

o

1 O ! "1

0 o o^^^ ^ O O

" " 1 1 T1 0

Y = •0.659 8 + 0.026 3 X X = cars/da y 1 1 1 1 -

-

_ ] 0 4,00 0 8.00 0 12.00 0 16.00 0 20.00 0 24.00 0 28.00 0 32.00 0 36,00 0 38.00 0 TRAFFI C VOLUME , cars/da y Figur e 12-4 . Arithmeti c mea n o f ai r lea d level s by traffi c count , Dallas , 1976.3 " I n addition , durin g thi s phase , dat afo r indoor

outdoo r comparison s o f

ai r lea dlevel s wer e col

lected . I n tw o areas , wit htraffi c densitie s o f 10,00 0 an d20,00 0 cars/day , hig hvolum e sampler s measure dai r

lea doutsid e o f

selecte dhouses . A t

th e sam e time , indoo r

ai r lea dvalue s fo r

thes e house s wer e als o collected . Tabl e 12-1 6 show s th e findings . Approximatel y atenfol ddifferenc e wa s foun dbe

twee n indoor-outdoo r

value s in bot hlocations . I t ha s bee n postulate dtha t a t leas t par t o f thi s differenc e i s th e resul t

o f usin g ai r

conditioners . TABL E 12-16 . MEA N AI R LEA D LEVEL S (fj.g/m3) INDOOR S AN D OUTDOOR S ATTW O TRAFFI C DENSITIES , DALLAS , TEX . 1976* " 10.00 0 cars'da y 20.00 0 car s da y

Outdoo r Indoo r Outdoo r Mea n N 0.18 2

9 0.91 8

9 0.19 9

5 2.10 5

5 I n addition , fo r

al l distance s measure d( 5 t o 10 0 f t fro mth e road) , ai r

lea dconcentration s decline d rapidl y wit hdistanc e fro mth e street . A t 5 0 f t con centration s wer e abou t

5 5 percen t

o f th e stree t

con centration ; a t

10 0 f t concentration s wer e les s tha n 4 0 percen t o f th e stree t

concentrations . I n ai r lea dcol

lection s fro m5 t o 10 0 f t fro mth e street , approx imatel y 5 0 percen t

o f th e airborn e lea dwa s i n th e respirabl e rang e ( < 1 fim) an dth e proportion s i n eac hsiz e clas s remaine dapproximatel y th e sam e a s th e distanc e fro mth e stree t increased . Soi l lea dconcentration s wer e highe r in area s wit h greate r traffi c densit y (Tabl e 12-17) . Th e maximu m soi l leve l obtaine dwa s 73 0 figlg. Traffi c density , vehicles/da y Soi l lea d levels . II gig <1.00 0 1,000-13,49 9 13.500-19,49 9 >19,50 0 73. 6 92. 2 110. 9 105. 9 Dustfal l sample s fo r

2 8 day s fro m9 location s showe dn o relationshi p t o traffi c densities , bu t out doo r level s wer e a t

leas t 1 0 time s th e indoo r

con centratio n in nearb y residences . I n th e secon dphase , thre e group s o f subjects , 1 t o 6 year s old , 1 8 t o 4 9 year s old , an d5 0 year s an d older , wer e selecte din eac ho f 4 stud y areas . Traffi c densitie s selecte dwere : < 1,000 , 8,00 0 t o 14,000 , 14,00 0 t o 20,000 , an d20,00 0 t o 25,00 0 cars/day . Th e stud y group s average dabou t 3 5 subjects , althoug hth e numbe r

varie dfro m2 1 t o 50 . Th e smalles t group s wer e fro mth e highes t traffi c densit y area . N o relationshi p betwee n traffi c densit y an d bloo dlea dlevel s in an y ag e group s wa s foun d (Figur e 12-5) . Bloo dlea dlevel s wer e significantl y highe r in children , 1 2 t o 1 8 figldl, tha n in adults , 9 t o 1 4 figldl.

-

-

~ 1 1 1 1



# A.

f ' \

FEMALE S < 9 * / \

\

MALE S < 9

** -VfC—' " MALE S >4 9 °~~ ^ j ^

_Q

_FEMALES19-4 9 ef " .Q

_5

FEMALE S >4 9

1 1 1 1 < 1,00 0 1,000-13.50 0 13,500 - 19,50 0 19,500 -

38.00 0 TRAFFI C DENSITY , cars/da y Figur e 12-5 . Bloo d lea d concentratio n an d traffi c densit y b y sex an d age , Dallas , 1976. 3 4 Galk e e t al. 4 3 studie dbloo dlea dlevel s i n 18 7 Sout hCarolin achildre n l t o 5 year s ol di n relatio n t o lea din soi l an dt o automobil e traffic . Th e arithmeti c mea n bloo dlea dleve l wa s relate dt o bot h factors , a s show n i

n Tabl e 12-18 . 12-1 2P.2 2

TABL E 12-18 . BLOO D LEA D CONCENTRATION S I N RELATIO N T O SOI L LEA D CONCENTRATION S AN D TRAFFI C DENSITY* * (MQ/dl )

Soi l lea d concentrations . uglg <58 5 >58 5 Tota l Lo wmea n

(951-167 7 cars/day ) 3 2 (7)a 36(10 ) 34(9 ) Automobil e traffi cdensit y

Hig h mea n (2446-963 7 cars/day ) 41(8 ) 43(11 ) 42(10 ) Al l densitie s

35(8 ) 41(11 ) 38(10 )

a Standar d deviatio n o f a singl e observation . Capri o e t

al. 5 1 compare dbloo dlea dlevel s an d proximit y t o majo r

traffi c arterie s i n astudy , re porte din 1971 , tha t

include d522 6 childre n i n Newark , Ne w Jersey . Ove r 5 7 percen t

o f th e childre n livin g withi n 10 0 f t o f roadway s ha dbloo d lea dlevel s greate r

tha n 4 0 figldl. Fo r

thos e livin g betwee n 10 0 an d20 0 f t fro mth e roadways , mor e tha n 2 7 percen t

ha dsuc hlevels ; an da t distance s greate r tha n 20 0 ft , 3 1 percen t exceede d4 0 figldl. Tabl e 12-1 9 indicate s tha t th e effec t

o f automobil e traffi c wa s see n onl y in th e grou p tha t live dwithi n 10 0 f t o f th e road . TABL E 12-19 . BLOO D LEA D LEVEL S I N CHILDRE N AGE D 1 T O 5 I N NEWARK , NJ , I N RELATIO N T O DISTANC E O F RESIDENC E FRO M A MAJO R ROADWAY , 1971 "

(M9/dl ) Distanc e o f residenc e fro m roadway , ft <10 0 100-20 0 >20 0 numbe r Percen t bloo d lea d level s <4 0 42. 6 72. 4 68. 4 340 1 40-5 9

49. 3 24. 2 26. 9 156 2 >6 0 8. 1 3. 4 4. 7 26 3 Numbe r

75 8 507 396 1 522 6 N o othe r source s o f

lea dwer e considere di n thi s study . Dat afro mothe r

studie s o n mobil e source s in

dicate , however , tha t

i t i s unlikel y tha t

th e bloo d lea dlevel s observe di n thi s stud y resulte dentirel y fro mautomotiv e exhaus t emissions . Daine s e t

al . studie dblac k

wome n livin g nea r

a heavil y travele dhighwa y in Ne w Jersey. 5 2 Th e sub

ject s live di n house s o n street s parallelin g th e high

way a t 3 distances , 3.7 , 38.1 , an d121. 9 m . Ai r lea d a s wel l a s level s fo r

bloo dlea dwer e measured . Mea n annua l ai r

lea dconcentration s wer e 4.60 , 2.41 , an d2.2 4 /ttg/m 3 , respectively , fo r th e 3 dis

tances . Th e mea n ai r

lea dconcentratio n fo r

th e are a closes t t o th e highwa y wa s significantl y differen t fro mtha t i n bot hth e secon dan dthird , bu t th e mea n ai r lea dconcentratio n o f

th e thir dare awa s no t

sig

nificantl y differen t

fro mtha t

o f th e second . Th e result s o f

th e bloo dlea ddetermination s parallele d thos e o f th e ai r lead . Mea n bloo dlea dlevel s o f th e 3 group s o f

women , i n orde r

o f increasin g distance , wer e 23.1 , 17.4 , an d17. 6 fig/100g, respectively . Again , th e first

grou p showe dasignificantl y highe r mea n tha t

th e othe r

two , bu t

th e secon dan dthir d groups ' bloo dlea dlevel s wer e simila r t o eac hother . Daine s e t

al., 5 2 in th e sam e publication , reporte da secon dstud y in whic hth e distance s fro mth e high

way wer e 33. 5 an d45 7 meter s an dwher e th e sub

ject s wer e whit e uppe r middl e clas s women . Althoug hth e ai r

lea dlevel s wer e triviall y differen t at thes e tw o distances , th e bloo dlea dlevel s di dno t differ . Becaus e th e resident s neares t th e roa dwer e alread y 3 3 m( + 10 0 ft ) fro mit an dbecaus e othe r studie s ha dshow n a n exponentia l declin e in ai r lea d level s wit hincreasin g distanc e fro mth e road , reach

in g backgroun dai r

lea dlevel s at

25 0 ft , th e explana

tio n may li e i n th e fac t

th e ai r lea dlevels , althoug h statisticall y different , wer e insufficien t t o b e reflecte di n th e bloo dlea dlevels . I t i s no t possibl e t o substantiat e thi s possibilit y becaus e th e observe dai r lea dvalue s fo r

th e tw o distance s wer e no t reported . I n 1964 , Thoma s e t

al. 5 3 investigate dbloo dlea d level s i n 5 0 adult s wh o ha dlive dfo r a t leas t 3 year s withi n 25 0 f

t o f afreewa y (Lo s Angeles ) an dthos e o f 5 0 other s wh o ha dlive dfo r alik e perio dnea r

th e ocea n o r a t leas t 1 mil e fro mafreeway . Mea n bloo d lea dlevel s fo r

thos e nea r

th e freewa y wer e 22. 7 ± 5. 6 fo r me n an d16. 7 ± 7. 0 figldl fo r women . Thes e concentration s wer e highe r tha n fo r contro l subject s livin g nea r

th e ocean : 16. 0 ± 8. 4 figldl fo r me n an d 9. 9 ± 4. 9 figldl

fo r women . Th e highe r

values , however , wer e simila r

t o thos e o f

othe r Lo s Angele s populations . Measure dmea n ai r concentration s o f lea din Lo s Angele s fo r

Octobe r 196 4 wer e 12.2 5 ± 2.7 0 jag/m 3 a t

alocatio n 3 0 f

t fro mth e San Bernar

din o freeway ; 13.2 5 ± 1.9 0 /u.g/m3 a t anothe r loca

tio n 4 0 f t fro mth e sam e freeway ; 6.4 0 ±2.1 5 /Lig/m 3 a t afourt hfloo r

locatio n 30 0 f

t fro mth e freeway ; an d4.6 0 ± 1.9 2 /u.g/m3 1 mil e fro mth e neares t free

way . Th e investigator s conclude dtha t th e difference s observe dwer e consisten t wit hcoastal-in

lan datmospheri c an dbloo dlea dgradient s i n th e Lo s Angele s basi n an dtha t th e effec t

o f residentia l proximit y t o afreewa y (2 5 t o 25 0 ft ) wa s no t demon

strated . 12.3.1.1. 2 Britis hstudies . I n aBirmingham , Eng

land , study , mea n bloo dlea dlevel s i n 4 1 male s an d 5 8 female s livin g withi n 80 0 mo f ahighwa y in

terchang e wer e 14.4 1 an d10.9 3 figldl, respectively , jus t prio r t o th e openin g o f

th e interchang e i n Ma y 1972.5 4 pro mOctobe r

197 2 t o Februar y 197 3 th e respectiv e value s fo r

th e sam e individual s wer e 18.9 5 an d14.9 3 fig/dl. I n Octobe r 197 3 the y wer e 12-1 3P.2 3

23.7 3 an d19.2 1 figldl. Th e investigator s note d difficultie s i n th e bloo dcollectio n metho ddurin g th e baselin e perio dan dchange dfro mcapillar y t o venou s bloo dcollectio n fo r th e remainin g tw o sam ples . T o interpre t

th e significanc e o f

th e chang e i n bloo dcollectio n method , som e individual s gav e bot hcapillar y an dvenou s bloo da t th e secon dcol

lection . Th e mean s fo r bot hcapillar y an dvenou s blood s wer e calculate dfo r th e 1 8 male s an d2 3 female s wh o gav e bot htype s o f blood. 5 5 Th e venou s bloo dmea n value s fo r

bot hthes e male s an dfemale s wer e lower , 0. 8 an d0. 7 figldl, respectively . I f thes e difference s i n mean s wer e applie dt o th e mean s o f th e thir dseries , th e mean s fo r male s woul db e reduce dt o 24. 8 ,ug/d l an dtha t fo r th e female s t o 18. 7 figldl. Thes e adjuste dmean s stil l sho w a n in

creas e ove r

th e mean s obtaine dfo r th e first series . O n th e othe r

hand , discardin g th e mean s calculate d fo r th e first serie s an dcomparin g onl y th e mean s fo r venou s bloods , namel y serie s tw o an dthree , agai n show s a n increas e fo r

bot hgroups . Th e increas e i n bloo dlea dvalue s wa s large r tha n expecte dfollow

in g th e mode l o f

Knelso n e t

al. 5 6 becaus e ai r

lea d value s nea r

th e roa dwer e approximatel y 1 ,u.g/m 3

. Th e investigator s conclude dtha t eithe r th e lea d aeroso l o f

ver y smal l particle s behave dmor e lik e a ga s s o tha t

considerabl y mor e tha n 3 7 percen t o f in

hale dmateria l wa s absorbe do r tha t ingestio n o f lead-contaminate ddus t migh t b e responsible . Studie s o f

taxica b driver s hav e employe ddifferen t variable s t o represen t

th e drivers ' lea dexposure, 575 8 on e bein g night

- versu s day-shif t drivers; 5 1 th e other , mileag e driven. 5 8 I n neithe r cas e wa s an y differenc e observed . Th e studie s reviewe dsho w tha t automobile s pro duc e sufficien t

emission s t o increas e ai r an dnearb y soi l concentration s o f

lea da s wel l a s increas e bloo d lea dconcentration s i n childre n an dadults . Th e proble mi s o f

greate r importanc e whe n house s ar e locate dwithi n 10 0 f

t (3 0 m ) o f

th e roadway . 12.3.1. 2 STATIONAR Y SOURC E STUDIE S 12.3.1.2. 1 Primar y smelters . Mos t studie s o f

nonin

dustry-employe dpopulation s livin g i n th e vicinit y o f industria l source s o f

lea dpollutio n wer e triggere d becaus e evidenc e o f

sever e healt himpairmen t ha d bee n found . Subsequently , extremel y hig hexposure s an dhig hbloo dlea dconcentration s wer e found . Th e followin g studie s documen t th e healt hproblem s tha t ca n develo p a s wel l a s som e o f th e relationship s be

twee n environmenta l exposur e an dhuma n response . 12.3.1.2.1. 1 El

Paso, Texas. I n 1972 , th e Cente r fo r Diseas e Control , formerl y th e Communicabl e Dis

eas e Center , studie dth e relationship s betwee n bloo d lea dlevel s an denvironmenta l factor s i n th e vicinit y o f aprimar y smelte r

emittin g lead , copper , an dzin c locate di n E l Paso , Texas , tha t ha dbee n i n operatio n sinc e th e lat e 1800's. 33

- 5 9 Estimate dlea demission s fro mthi s smelte r

wer e 29 7 metri c ton s i n 1969 , 51 9 metri c ton s i n 1970 , an d31 7 metri c ton s i n 1971, 3 3 Thes e figures , however , includ e onl y stac k emis

sions ; th e quantitie s i n fugitiv e emission s vi aventila

tion , windows , etc. , ar e unknown . Dail y high

volum e sample s collecte do n 8 6 day s betwee n Februar y an dJun e 197 2 average d6. 6 /ig/m 3 o f lead . Concentration s range dfro m0.4 9 t o 7 5 /ig/m 3

. Thes e ai r

lea dlevel s fel l of

f rapidl y wit hdistance , reaching , a s woul db e expected , backgroun dvalue s approximatel y 5 k

mfro mth e smelter . Level s wer e highe r downwind , however . Hig hconcentration s o f lea di n soi l an dhousedus t wer e found , wit hth e high

es t level s occurrin g nea r

th e smelter . Th e geometri c mean s o f 8 2 soi l an d10 6 dus t

sample s fro mth e sec to r closes t t o th e smelte r

wer e 179 1 an d402 2 figlg, respectively . Geometri c mean s o f bot hsoi l an ddus t lea dlevel s nea r

th e smelte r

wer e significantl y highe r tha n thos e i n stud y sector s 2 o r 3 kmfarthe r

away . Sixty-nin e percen t

o f childre n 1 t o 4 year s ol dliv

in g nea r th e smelte r

ha dbloo dlea dlevel s > 4 0 /xg/dl , an d1 4 percen t

ha dbloo dlea dlevel s tha t exceede d6 0 figldl. Concentration s in olde r in

dividual s wer e lower ; nevertheless , 4 5 percen t o f th e childre n 5 t o 9 year s old , 3 1 percen t o f th e in

dividual s 1 0 t o 1 9 year s old , an d1 6 percen t o f th e individual s abov e 1 9 ha dbloo dlea dlevel s al l ex ceedin g 4 0 figldl. Th e dat apresente dpreclud e calculation s o f

mean s an dstandar ddeviations . Dat afo r peopl e age d1 t o 1 9 year s livin g nea r th e smelte r showe darelationshi p betwee n bloo dlea d level s an dconcentration s o f lea di n soi l an ddust . Fo r individual s withbloo dlea dlevel s >4 0 figldl, th e geometri c mea n concentratio n o f lea di n soi l a t thei r home s wa s 258 7 figlg, wherea s fo r thos e wit ha bloo dlea dconcentratio n <4 0 figldl, hom e soil s ha d ageometri c mea n o f

141 9 figlg. Fo r

housedust , th e respectiv e geometri c mean s wer e 644 7 an d206 7 Mg/g

Analysi s foun dth e effec t o f lengt ho f

residenc e t o b e importan t

onl y i n th e secto r

neares t th e smelter . Forty-thre e percen t

o f th e 1

- t o 19-year-old s wh o ha dlive dther e 2 o r

mor e year s ha dbloo dlea d value s 24 0 figldl, wherea s onl y 1 8 percen t o f th e 1

- t o 19-year-old s wh o ha dlive dther e les s tha n 2 year s ha dsimila r

levels . Additiona l source s o f

lea dwer e als o investigated . A relationshi p wa s foun dbetwee n bloo dlea dcon 12-1 4centration s an dlea dreleas e fro mpottery , bu t th e numbe r o f individual s involve dwa s ver y small . N o relationship s wer e foun dbetwee n bloo dlea dlevel s an dhour s spen t

ou t o f door s eac hday , schoo l atten dance , o r employmen t

o f aparen t a t th e smelter . Th e reporte dprevalenc e o f

pic aals o wa s minimal . I t wa s conclude dtha t

th e primar y facto r

associ

ate dwithelevate dbloo dlea dlevel s in th e childre n wa s ingestio n o r

inhalatio n o f

dus t containin g lead . Dat ao n dietar y intak e o f lea dwer e no t

obtaine d becaus e th e climat e an dproximit y t o th e smelte r prevente dan y farmin g i n th e area . I t wa s unlikel y tha t th e dietar y lea dintake s o f th e childre n fro m nea r th e smelte r

an dfarthe r

awa y wer e significantl y different . 12.3.1.2.1. 2 Kellogg, Idaho. I n 1970 , EP A carrie d ou t astud y o f

alea dsmelte r

in Kellogg , Idaho. 60

- 6 1 Th e stud y wa s par t

o f anationa l effort

t o determin e th e effect s o f

sulfu r dioxide , tota l suspende dparticu

late , an dsuspende dsulfates , singl y an di n combina

tio n wit hothe r

pollutants , o n huma n health . I t focuse do n mixture s o f th e sulfu r

compound s an d metals . Althoug hit

wa s demonstrate dtha t childre n ha devidenc e o f

lea dabsorption , insufficien t en vironmenta l dat awer e reporte dt o allo w furthe r quantitativ e analyses . I n 1974 , followin g th e hospitalizatio n o f tw o childre n wit hsuspecte dacut e lea dpoisoning , CD C joine dth e Stat e o f Idah o in acomprehensiv e stud y o f childre n i n th e area. ' 6 2 Th e studie s conducte di n thi s are aunfortunatel y use dabewilderin g arra y o f designation s i n thei r

reports , bu t

al l ar e relate dt o th e sam e industria l complex . Th e sourc e o f

exposur e wa s a*smelte r whos e record s showe dtha t

emission s o f

lea dint o th e at mospher e average d8. 3 metri c ton s pe r mont hfro m 195 5 t o 1964 , 11. 7 metri c ton s fro m196 5 t o Sep

tembe r 1973 , an d35. 3 metri c ton s fro mOctobe r 197 3 t o Septembe r

1974. 6 2 I n Septembe r

1973 , afir e destroye dth e mai n filtratio n facilit y fo r th e smelter . Th e stud y wa s initiate din Septembe r 1974 , afte r

tw o childre n wer e hospitalize dwithsymptom s o f lea d poisoning . A t

tha t time , bloo dlea dlevel s 24 0 figldl wer e foun din 38 5 (41. 9 percent ) o f 91 9 childre n les s tha n 1 0 year s ol dwh o wer e examined . Abou t 9 9 per cen t o f th e 17 2 childre n livin g withi n 1. 6 k mo f th e smelte r ha dbloo dlea dvalue s 24 0 figldl. Th e mea n bloo dconcentratio n decline dwithdistanc e fro mth e poin t o f emissio n (Tabl e 12-20) . Bloo dlea dlevel s wer e consistentl y highe r i n childre n 1 t o 4 year s ol d tha n in thos e 5 t o 9 year s old . I n addition , highe r level s i n childre n wer e associate dwit hreporte dac tiv e ingestio n o f

lead-containin g materia l (pica) , withlowe r

socioeconomi c status , an dwit hparenta l employmen t

a t th e smelte r

o r a t alea dmine . A sig

nifican t negativ e relationshi p betwee n bloo dlea d TABL E 12-20 . GEOMETRI C MEA N BLOO D LEA D LEVEL S B Y ARE A COMPARE D WIT H ESTIMATE D AI R LEA D LEVEL S FO R 1 - T O 9-YEAR-OL D CHILDRE N LIVIN G NEA R IDAH O SMELTE R (Geometri c standar d deviations , sampl e sizes , an d distance s fro m smelte r ar e als o given) " G M bloo d lead . ug/d l 65. 9 47. 7 33. 8 32. 2 27. 5 21. 2 GS D 1.3 0 1.3 2 1.2 5 1.2 9 1.3 0 1.2 9 Sampl e siz e 17 0 19 2 17 4 15 6 18 8 9 0 Estimate d ai rlead . /xg/m J 18. 0 14. 0 6. 7 3. 1 1. 5 1. 2 Distanc e fro m smelter . k m 0 - 1. 6 •1.6 - 4. 0 4.0-10. 0 10.0-24. 0 24.0-32. 0 abou t 7 5

a EPAanalysi s o f dat a fro m Yanke l e t al. 1 leve l an dhematocri t

valu e wa s found . Seve n o f 4 1 childre n (1 7 percent ) withbloo dlea dlevel s 28 0 figldl wer e diagnose db y th e investigator s a s bein g anemi c o n th e basi s o f

hematocri t

les s tha n 3 3 per cent , wherea s onl y 1 6 o f 100 6 childre n (1. 6 percent ) withbloo dlea dlevel s < 8 0 figldl wer e s o diag

nosed . Althoug hn o over t

neurologi c diseas e wa s ob

serve di n childre n wit hhighe r lea dintake , difference s wer e foun di n nerv e conductio n velocity . Detail s o f

thi s findin g wer e discusse di n apreviou s chapter . Beginnin g in 1971 , ambien t concentration s o f

lea d in th e vicinit y o f

th e smelte r

wer e determine dfro m particulat e matte r

collecte di n high-volum e ai r samplers . Dat aindicate dtha t monthl y averag e level s measure di n 197 4 (Figur e 12-6 ) wer e thre e t o fou r time s th e level s measure di n 1971. 6 3 Individua l exposure s t o lea dwer e estimate db y interpolatio n fro mthes e high-volum e data , an dastron g correla

tio n wa s foun dbetwee n th e estimate s an dth e measure dbloo dlea dlevel s ( r + 0.72) . 12-1 5P.2 5

Figur e 12-6 . Monthl y ambien t ai r lea d concentration s i n Kellogg , Idaho , 197 1 throug h 1975. 6 3 

### Subsequently , Yanke l et

al . publishe dadditiona l informatio n concernin g th e 197 4 study a s well a s th e result s o f afollow-up study conducte di n 1975. ' Th e follow-up wa s undertake n t o determin e th e effec

tivenes s o f contro l measure s initiate dafte r th e 197 4 study . Between Augus t

197 4 an dAugus t

1975 , th e mea

n annual ai r

leadlevel s decrease da t al l station s monitore d(Figur e 12-7) . In orde r o f increasin g dis

tanc e fro mth e smelter , th e concentration s i n th e tw o year s wer e 18. 0 t o 10. 3 /Ag/m 3 

### , 14. 0 t o 8. 5 /ng/m3 

### , 6. 7 t o 4. 9 jug/m3 

### , and , finally, 3. 1 t o 2.5/ig/m 3 

### a t 1 0 t o 24 km . Simila

r reduction s were note di n th e housedus t leadconcentrations . In aseparat e report , vo n Lindern an dYanke l describe dreduction s i

n bloo dleadlevel s o

f childre n fo r who mdetermination s wer

e mad e i n bot hyears. 6 0 

### I t wa s pointe dou t

tha t th e childre n wit

hth e highes t bloo dleadlevel s i

n 197 4 hadbeen relocated ; thei r removal an dsubsequent

relocatio n woul dcompli

cate an y analysi s i

n whichthey wer

e included . T o compensate fo

r this , th e author s als o presente dsepa ratel y th e bloo dleadlevel s for thos e childre n livin g i n th e sam e home bot

hyears . Thi s greatl y reduce d th e number

o f observation s reported . Th e result s (Tabl e 12-21 ) demonstrat e that significant

reduc

tion s i n bloo dleadconcentratio n ca n b e effected , an dtha t they were observe di

n eac hstudy area . In area s III , IV , an dV , al l mea n bloo dlea

dlevel s wer

e <4 0 figldl. Th e report

o f Yanke l et

al. 1 

### showedtha t

ther e I 1 AUG . 197 4 rrrr\ AUG . 197

5

CONTRO L 

# D_D_n 3 4 5 B Y ARE A (SE E TEXT ! Figur e 12-7 . Annua l ambien t ai r lea d concentration , b y area , befor e th e August 197 4 an d Augus t 1975 surveys. 1 

### wer e reduction s i

n environmenta l leadcontamina

tio n between 197 4 an d1975 , an dtha t th e correla

tion s between bloo dleadlevel s an denvironmenta l o r demographi c factor s wer e consisten t

fro mon e yea r t o th e next . Fiv e factor s influenced , i n a statisticall y significant

manner , th e probability of a chil ddevelopin g a

n excessiv e bloo dleadlevel : 1 . Concentration s of

lea di n ambien t

ai r (Mg/m 3 

### ) . 2 . Concentratio n o

f leadi n soi l (ppm) . 3 . Ag e (years) . 4 . Cleanlines s o

f th e hom e (subjectiv e evaluatio n code d0 , 1 , and2 , wit h2 signifying dirtiest) . 5 . Genera l classificatio n o f th e parents ' oc cupatio n (dimensionless) . Althoug hth e stronges t

correlatio n foundwas be

twee n bloo dlea

dlevel andair

lea dlevel , th e author s conclude dthat

i t was unlikel y that

inhala

tio n o f contaminate dair

alon e coul dexplai n th e ele

vate dbloo dleadlevel s observed . Yanke l an dvo n Lindern reasone dtha t even thoug hai r

leadwas th e principa l source , amajor rout e o f exposure was th e ingestio n of leadi n soi l anddust. 1 

### They propose dtha t t o protec t

th e health 12-1 6P.2 6

TABL E 12-21 . MEA N BLOO D LEA D LEVEL S I N CHILDRE N LIVIN G I N VICINIT Y O F A PRIMAR Y LEA D SMELTER , 1974 an d 197 5

Grou p N H N I I X Stud yare a an d dat a se t II I N •) ( N I V X N V X Bloo d level s >80,ug/d| a i n 197 4 tes t Reteste d i n 1975 Differenc e Bloo d level s >6 0 bu t <8 0 /ug/d l i n 1974 tes t Reteste d i n 1975 Differenc e Bloo d level s <60n.g/d l i n 197 4 tes t Reteste d i n 1975 Differenc e 90. 2 52. 3 -38. 0

64. 5 — 47. 4 8 -17. 2 — 52. 3 — 80. 0

61. 0 -19. 0

69. 6 50. 3 -19. 3

47. 0 45. 6 37. 4 2 3 36. 0 2 0 39. 8 -14.9 —-11. 0 —- 5. 8 1 4 43. 7 37. 4

- 6. 3 61. 0

51. 0 -10. 0 43. 4 33. 5

- 9. 9

a Adapte d fro m vo n Linder n an d Yankel. 6 3

o f th e childre n i n thi s are ath e regulatio n o f environ

menta l standard s mus t

tak e int o accoun t

al l o f thes e route s o f exposure . Thes e investigator s develope damathematica l mode l base do n th e 197 4 dat atha t include deac ho f th e fiv e factor s tha t

ha dbee n show n t o b e correlate d wit hincrease dbloo dlea dlevels . Th e model , show n below , ca n b e use dt o estimat e th e effec t o f varia

tion s i n th e environmenta l factor s o n mea n bloo d lea dlevel s i n children : 1 n (Pb-B ) =3.1 + 0.04 1 (Air ) + 2. 1 x 10 5 (Soil ) + 0.08 7 (Dust ) + 0.01 8 (Age ) + 0.02 4 (Occupation) . (Se e abov e fo r

definitio n o f

units) . (12-6 ) 12.3.1.2.1. 3 CDC-EPA study. Bake r e t al., 3 1 i n 1975 , surveye d177 4 childre n 1 t o 5 year s old , mos t o f who mlive dwithi n 4 mile s o f 1 9 lead , copper , o r zin c smelter s locate di n variou s part s o f th e Unite d States . Bloo dlea dlevel s wer e modestl y elevate d nea r tw o o f th e 1 1 coppe r

an dtw o o f

th e fiv e zin c smelters . Althoug hbloo dlea dlevel s i n childre n wer e no t elevate di n th e vicinit y o f thre e lea d smelters , thei r

FE P level s wer e somewha t highe r tha n thos e foun di n controls . Increase dlevel s o f lea d an dcadmiu mi n hai r

sample s wer e foun dnea r lea d an dzin c smelters ; thi s wa s considere devidenc e o f externa l exposure . N o environmenta l determina

tion s wer e mad e fo r

thi s study . 12.3.1.2.1. 4 Meza Valley, Yugoslavia. A Yugosla

via n stud y i n th e Mez aValle y investigate dex posure s t o lea dfro mamin e an dasmelte r ove r a perio do f

years. 646 9 Th e min e an dsmelte r ar e lo

cate dnea r

arive r flowin g i n th e valley . Th e smelte r produce s abou t

23,00 0 metri c ton s annually . Afte r contro l equipmen t

wa s installe do n 1 o f

2 lead-emit

tin g stacks , emission s wer e calculate dt o b e 203. 2 metri c tons/year . I n 1967 , 24-h r lea dconcentration s measure dfro m4 differen t day s varie dfro m1 3 t o 8 4 /*g/m 3 i n th e villag e neares t th e smelter , an dcon centration s o f

u p t o 6 0 /ig/m 3 wer e foun da s far a s 5 kmfro mth e source . Mea n particl e siz e i n 196 8 wa s <0. 8 /im. Th e lea dlevel s wer e abou t 25,00 0 pp mi n th e mos t contaminate darea . Analysi s o f som e com mo n foodstuffs showe dconcentration s tha t wer e 1 0 t o 100 time s highe r

tha n correspondin g foodstuf f fro mth e leas t

expose dare a(Mezica). 6 4 After Januar y 196 9 whe n partia l contro l o f emis

sion s wa s establishe da t th e smelter , weighte d averag e weekl y exposur e wa s calculate dt o b e 2 7 figlm*i n th e villag e nea r th e smelter . I n contras t t o this , th e cit y o f

Zagreb, 6 5 whic hha s n o larg e station

12-1 7P.2 7



### ar y sourc e o

f lead , ha da n averag e weekl

y ai r lea d level o f 1. 1 figlm*. I n 1968 , th e averag e concentratio n o f ALA i n urin e sample s fro

m91 2 inhabitant s o

f six village s varie db y villag e fro

m9. 8 t o 1 3 mg/liter . A contro l grou p ha damea

n ALA o f 5. 2 mg/liter . Dat aon lead i n bloo dan dth e ag e an dse x distributio n o

f th e villager s wer

e no t given. 6 4 

### O f th e 91 2 examined , 55 9 ha da n ALA leve l > 1 0 mg/liter o f urine . In 1969 , amore extensiv e study o f 28 6 individual s wit

hALA >1 0 mg/liter

was under

taken. 6 6 

### ALA- U decrease dsignificantly fromth e previou s year . When th e publishe ddat awer e ex amine dclosely , ther e appeare dt o b e som e discre

pancie s i n interpretation . Th e exposure fro mdus t an dfro mfoodmigh

t hav e been affectedb

y th e con tro l devices , bu t

no dat awer

e collecte dt o establis h this . In on e village , Zerjau , ALA- U droppe dfro m 21. 7 t o 9. 4 mg/liter

i n childre n 2 t o 7 year s o

f age . Correspondin g ALA- U value s fo r 8

- t o 15-year-old s an dfo r adul t me n an dwome

n were reduce dfro

m 18. 7 t o 12.1 , from23. 9 t o 9.9 , an dfro m18. 5 t o 9. 0 mg/liter , respectively . Becaus e leadconcentration s i n air 6 5 

### eve

n afte r 196 9 indicate da

n averag e expo sure o f 2 5 ^g/m 3 

### , i

t i s possibl e that

som e othe r ex planatio n shoul db e sought . Th e autho r indicate di

n th e report tha t th e decreas e i

n ALA- U showed"th e dependenc e o n meteorologic , topographic , an dtech

nologi c factors." 6 6 

### Lea di n bloo dwas determined , but accordin g t o th e report

"determinatio n o

f leadi n bloo dcoul dno t

b e usedfo

r exposure evaluatio n becaus e al l obtaine dvalue s were i n th e norma l limits " (unde r

8 0 figldl

bloo da s define db

y th e author). fi 

### f > I n ligh t o f curren t knowledge , thi s defini

tio n o f norma l level s i s excessively high . Th e excretio n o

f nonchelate dleadi

n urin e i n 8. 5 percen t o f 20 9 individual s was abov e 0. 1 mg/liter . Th e highes t

valu e recorde dwa s 0.1 9 mg/liter . When treate dwit

hC aEDTA , th e mobilize dleadi n th e urin e o f thes e individual s range dfro m0. 5 t o 4. 2 mg/liter , indicatin g th e presenc e o f tota l body bur

den s rangin g fro

mnorma l t o te n time s normal. 666 8 

### Anothe r findin g o

f thi s projec t

was asignificant increas e i n reticulocytes , especiall y i n children. 6 6 

### Forty-seve n percent

o f expose dadult s complaine d o f pai n i n thei r bone s compare dwit

honly 3 percen t o f th e controls . Fuga s et al. 6 9 

### i n alate r repor t estimate dth e time

weighte daverag e exposure o f several population s studie ddurin g th e cours e o f thi s project . Stationary sampler s a s well a s personal monitor s were use dt o estimate th e exposure t o airborn e leadfo r variou s part s of th e day . Thes e value s were the n couple d wit hestimate dproportion s o f tim e a t whichthes e ex posure s held . In Tabl e 12-22 , th e estimate dtime

weighte dbloo dleadvalue s a s well a s th e observe d mea n bloo dleadlevel s fo

r thes e studie dpopulation s ar e presented . An increas e i n bloo dlea dvalue s oc cur s wit hincreasin g ai r

leadexposure . TABL E 12-22 . MEA N BLOO D LEA D LEVEL S I N SELECTE D YUGOSLAVIA N POPULATIONS , B Y ESTIMATE D WEEKL Y TIME-WEIGHTE D AI R LEA D EXPOSURE 6 9

Populatio n Rura l I Rura l I I Rura l II I Postme n Custom s officer s Stree t ca rdriver s Traffi c policeme n N 4 9 4 7 4 5 4 4 75 4 3 2 7 Time weighte d ai rlea d Mg/m 3 0.07 9 0.09 4 0.14 6 1. 6 1. 8 2. 1 3. 0 Mea n bloo d

lea d level , jjg/d l 7. 9 11. 4 10. 5 18. 3 10. 4 24. 3 12. 2 S D

4. 4 4. 8 4. 0 9. 3 3. 3 10. 5 5. 1 

### 12.3.1.2.1. 5 East

Helena, Montana. EPA i n 197 2 investigate dalead-emittin g smelter comple x i

n Eas t Helena , Montana. 6 0 

### Th e quantitie s o f leademission s wer e no t known . Air

leadconcentration , measure d i n 1969 , yielde daverage s fromseveral station s tha t varie dfrom0. 4 t o 4 /xg/m3 

### ; th e maximum24-hr valu e wa s foun dt o b e 1 5 figlm*. In th e cit y o f Helena , th e averag e concentratio n was 0. 1 jig/m 3



### . Leadi n soi l wa s foundt o b e 4000 , 600 , an d100 figlg at distance s o

f 1.6 , 3.2 , an d6. 4 k

m(1 , 2 , an d4 miles) , respectively , fromth e smeltin g complex . Un

contaminate dsoi l nea

r th e Helen aValle y showe da mea n o f 1 6 figlg. Deposite dlead(dustfall ) wa s foundt o var

y fro m3 t o 10 8 mg/m 2 

### -mont h i n Eas t Helen aan dfro

m1 t o 7 mg/m^-mont

h i n Helena . Studie s on human s b

y Hamme r

e t al. 6 1 

### wer

e limite dt o children ; leadvalue s i n hai r an dbloo d wer e foundt o b e higher

i n Eas t Helen athan i

n Helena , th e respectiv e average s bein g 15. 6 ± 5. 1 an d11. 6 ± 4. 0 figldl

i n bloo dan dabou t

4 0 an d1 3 ppmi n hair . Th e hai r

value s indicate ddifferential exposure t o lead . However , i n th e opinio n o

f th e in

vestigators , althoug hth e bloo dleadvalue s indicate d a n elevate dexposure , i

t hadno t been excessive . N o advers e healtheffects hadbeen note di n thes e children . 12.3.1.2.1. 6 Other

smelter studies. Othe r

report s i n th e literatur e hav e als o shown tha t peopl e livin g nea r smelter s hav e increase dburden s o f leadi n thei r bodies. 707 2 

### I t

i s clear , therefore , tha t

emission s from primary lea dsmelter s can caus e elevate dbloo dlead level s an dothe r

indicator s o

f increase dlea dburden s i n population s livin g nea

r thes e stationary emissio n sources . 12-1 8P.2 8

Th e questio n o f

th e accurac y o f

th e reporte d analyti c result s in thes e studie s i s difficul t t o addres s becaus e the y spanne daperio do f tim e i n whic hma jo r stride s wer e take n in improvin g analytica l tech

nology . Hence , th e mor e recen t studie s ar e likely , bu t no t necessarily , t o provid e mor e accurat e infor

mation . Althoug hman y o f

th e report s specifie dtha t th e bloo dlea dlevel s wer e don e in duplicate , thi s unfor

tunatel y doe s no t

ensur e thei r

accuracy . Thi s prob

le mi s discusse din mor e detai l in Chapte r 9 . 12.3.1.2. 2 Othe r

industria l sources . Exposure s fro mbot haprimar y an dsecondar y smelte r i n th e in

ner-cit y are ao f

Omaha , Neb . hav e bee n reporte db y Angl e e t al . i n aserie s o f

publications. 737 6 Studie d fro m197 0 t o 197 7 wer e childre n fro ma n urba n schoo l immediatel y adjacen t t o asmal l batter y plan t an ddownwin dfro mtw o othe r lea demissio n sources , school s i n amixe dcommercial-residentia l area , an dschool s in asuburba n setting . Children' s bloo dlea dlevel s wer e obtaine db y macr o techniqu e fo r 197 0 an d1971 , bu t

Delve s micr o assa y wa s use d fro m197 2 on . Th e differenc e fo r th e chang e i n tech

nique s wa s take n int o accoun t in th e presentatio n o f th e data . Ai r

lea dvalue s wer e obtaine db y Hi-Vo l samplers , an ddustfal l value s als o wer e collected . Tabl e 12-2 3 present s th e authors ' summar y o f al l th e data , showin g tha t

a s ai r lea dvalue s decreas e an d the n increase , dustfal l an dbloo dlea dvalue s follow . Th e author s use dregressio n models , bot hlog-linea r an dsemilog , t o calculat e ai r lead/bloo dlea dratio s an dobtaine dvalue s o f 10.0 4 an d0.4 , respectively . Th e 0. 4 valu e i s equivalen t t o arati o o f

10. 4 a t a n ai r lea dleve l o f

1. 0 pig/m 3

. TABL E 12-23 . AIR , DUSTFALL , AN D BLOO D LEA D CONCENTRATION S I N OMAHA , NEB. , STUDY , 1970-1977 a ' 75 - 7 6

Grou p Al l urba n children , sit e m: 1970-7 1 1972-7 3 1974-7 5 1976-7 7 Childre n a t schoo l c . sit e c : 1970-7 1 1972-7 3 1974-7 5 1976-7 7 Al l suburba n children , sit e r : 1970-7 1 1972-7 3 1974-7 5 1976-7 7 1.4 8 0.4 3 0.1 0 0.5 2 1.6 9 0.6 3 0.1 0 0.6 0 0.7 9 0.2 9 0.1 2 M 9

±l+ ± + +l+ + +l+ + + Air , m 3 IN) b 0.14(7:65 ) 0.08(8;72 ) 0.03(10:72 ) 0.07(12:47 ) 0.11(7:67 ) 0.15(8:74 ) 0.03(10:70 ) 0.10(12:42 ) 0.06(7:65 ) 0.04(8:73 ) 0.05(10:73 ) — Dustfall . ng m 3 - m o IN) C

— 10. 6 ±0.3(6 ) 6. 0 ±0.1(4 ) 8. 8 (7)

— 25. 9 ±2.4(5 ) 14. 3 + 4.1(4 ) 33. 9 (7 )

— 4. 6 ±1.1(6) 2. 9 ±0.9(4 ) — Blood . Mg'd l (N) d 31. 4 + 0.7(168 ) 23. 3 ±0.3(211 ) 20. 4 ±0.1(284 ) 22. 8 ±0.7(38 ) 34. 6 ±1.5(21 ) 21. 9 ±0.6(54 ) 19. 2 + 0.9(17 ) 22. 8 ±0.7(38 )

— 19. 6 ±0.5(81 ) 14. 4 ±0.6(31 ) 18. 2 ±0.3(185 ) r Pb-B » Pb-A = -0.9 5 ( N = 10 ) Pb- B = 10.0 4 Pb- A+ 17.0 6 r lnPb-B » Pb-A = 0.9 1 ( N = 10 ) 1 n Pb- B = 0. 4 Pb- AI 2.8 6 Bloo d lea d 1970-7 1 i s byth e macr o technique , correcte d fo ra n establishe d laborator ybia s o f 3 ng dl , macro-micro ; al l othe rvalue s ar e b yDelve s micr o assay . N = Numbe ro f months ; numbe ro f 24-hou rsamples . N = Numbe ro f months . N = Numbe ro t bloo d samples . Specifi c report s presen t variou s aspect s o f

th e wor k done . Blac k

childre n i n th e tw o elementar y school s closes t

t o th e batter y plan t

ha dhighe r

bloo d lead s (34. 1 figldl) tha n thos e i n elementar y an d junio r hig hschool s farthe r

awa y (26. 3 /xg/dl) . Bes t estimate s o f

th e ai r exposure s wer e 1.6 5 an d1.4 8 Mg/m 3 , respectively. 7 3 Th e late r stud y compare d thre e populations : urba n versu s suburba n hig h schoo l students , age s 1 4 t o 18 ; urba n blac k children , age s 1 0 t o 12 , versu s suburba n whites , age s 1 0 t o 12 ;

blacks , age s 1 0 t o 12 , wit hbloo dlea dove r 2 0 fig percen t versu s schoolmate s wit hbloo dlea dlevel s belo w 2 0 fig percent. 7 4 Th e urba n versu s suburba n hig hschoo l childre n di dno t diffe r significantly , 22. 3 ± 1. 2 t o 20. 2 ± 7. 0 figldl, respectively , wit h mea n value s o f

ai r lea dconcentration s o f 0.4 3 an d 0.2 9 figlm 3

. Fo r

th e 1 5 student s wh o ha denviron

menta l sample s take n fro mthei r homes , correlatio n 12-1 9coefficient s betwee n bloo dlea dlevel s an dsoi l an d

housedus t

lea dlevel s wer e 0.3 1 an d0.2 9 respec tively . Suburba n 10-to-12-year-old s ha dlowe r bloo d lea dlevel s tha n thei r

urba n counterparts , 17. 1 ± 0. 7 an d21. 7 ± 0. 5 figldl, respectively. 7 4 Ai r lea d exposure s wer e highe r i n th e urba n tha n i n th e suburba n population , althoug hth e averag e exposur e remaine dles s tha n 1 /xg/m 3

. Dustfal l lea dmeasure ments , however , wer e ver y muc hhigher : 32.9 6 mg/m 2 -mont h fo r

urba n 10-to-12-year-old s versu s 3.0 2 mg/m 2 -mont h fo r

suburba n ones . Soi l lea dan dhousedus t lea dexposur e level s wer e significantl y highe r

fo r th e urba n blac k

high-lea d grou p tha n fo r

th e urba n low-lea dgroup . A signifi

can t correlatio n (r

= 0.49 ) betwee n bloo dlea dan d soi l lea dlevel s wa s found . I n aDallas , Texas , stud y o f tw o secondar y lea d smelters , th e averag e bloo dlea dlevel s o f expose d childre n wa s foun dt o b e 3 0 figldl versu s a n averag e o f 2 2 figldl i n contro l children. 7 7 Fo r th e tw o stud y populations , th e ai r

an dsoi l lea dlevel s wer e 3. 5 an d 1. 5 /xg/m 3 an d72 7 an d25 5 ppm , respectively . Direc t automobil e traffi c exposur e wa s no t con sidered . I n Toronto , Canada , th e effect s o f tw o secondar y lea dsmelter s o n th e bloo dan dhai r lea dlevel s o f nearb y resident s hav e bee n extensivel y studied. 787 9 I n apreliminar y report , Robert s e t al. 7 8 state dtha t bloo dan dhai r

lea dlevel s wer e highe r i n childre n livin g nea r

th e tw o smelter s tha n i n childre n livin g i n a n urba n contro l area . Biologi c an denvironmenta l lea dlevel s wer e reporte dt o decreas e wit hincreasin g distanc e fro mth e smelte r stacks . A late r an dmor e detaile drepor t identifie dahig h rat e o f lea dfallou t

aroun dth e tw o secondar y smelters. 7 9 Fallou t

i n th e vicinit y o f

th e smelter s wa s cause dprimaril y b y larg e particulat e fugitiv e emis

sion s rathe r

tha n stac k

emissions . Lea demission s fro mth e tw o smelter s wer e estimate dt o b e 15,00 0 an d30,00 0 kg/yr . Lea dconcentration s i n soi l wer e a s hig ha s 40,00 0 an d16,00 0 ppm , respectively , clos e t o th e 2 smelter s an ddroppe dof f exponen tiall y wit hdistance . The y reache durba n back

groun dlevel s o f

10 0 t o 50 0 ppm , 20 0 t o 30 0 mfro m th e smelter . Horn , i n alate r report , pointe dou t

tha t th e extremel y hig hsoi l level s wer e th e resul t o f som e sample s containin g scra p batter y plate ; in hi s repor t h e state s tha t

th e soi l lea dlevels , excludin g thos e contaminate dsamples , approache d800 0 pp mi n nonresidentia l area s an dexceede d400 0 pp mi n severa l residentia l yards. 8 0 H e als o pointe dou t severa l othe r

deficiencie s i n th e data. 8 0 A genera l criticis mh e levele da t th e study' s interpretatio n wa s tha t th e author s conclude dtha t soi l lea dwa s th e mai n sourc e o f

lead , aputativ e findin g i n Horn' s view , especiall y considerin g tha t fe w soi l sample s wer e taken . Lea dconcentration s i n dustfal l wer e muc hhighe r a t 1 o f th e 2 smelters , exceedin g 150 0 mg/cm 2

- month . Thes e concentration s als o exhibite da n expo nentia l decreas e wit hdistanc e simila r t o tha t ob

serve dfo r

soils . Becaus e th e lea dfallou t occurre d ove r asmal l are aan dconsiste dprimaril y o f larg e particle s (i n som e case s th e mas s media n diamete r wa s a s larg e a s 4. 6 ± 1. 3 fim), i t wa s believe dtha t th e emission s originate dmainl y fro mdust-produc

in g operation s a t

lo w heigh t

rathe r tha n fro mstac k emissions. 7 8 Lea dconcentration s i n ai r rangin g fro m1. 0 t o 5. 3 /xg/m 3 wer e onl y twic e thos e foun dat othe r Toront o urba n site s awa y fro mth e smelte r (0. 8 t o 2. 4 /xg/m 3 ) . Th e rang e o f

dail y concentration s wa s muc hgreater . A t 6 0 mfro mth e stack , lea din 9 6 ai r sample s range dfro m0. 5 t o 72 5 /xg/m 3 , wherea s a t 22 0 m9 4 sample s varie dfro m<0. 5 t o 1 4 /ng/m 3

. Tw o group s o f childre n livin g withi n 30 0 mo f eac ho f

th e smelter s ha dgeometri c mea n bloo dlevel s o f 2 7 an d 2 8 /xg/dl , respectively ; th e geometri c mea n fo r 123 1 control s wa s 1 7 figldl. Twenty-eigh t percen t o f th e sampl e childre n teste dnea r on e smelte r

durin g th e summe r an d1 3 percen t

o f th e sampl e childre n teste d nea r th e secon dsmelte r

durin g th e winte r

ha dbloo d lea dlevel s >4 0 figldl. Onl y 1 percen t o f th e con trol s ha dbloo dlea dlevel s >4 0 /xg/dl . Fo r children , bloo dlea dconcentration s increase dwithproximit y t o bot hsmelter s bu t

thi s tren ddi dno t

hol dfo r adult s generally . Lea dlevel s in hai r

sample s average d4 1 figlg i n th e smelte r

area s an d1 3 figlg in th e contro l area. 7 8 Bloo dlea dan dhai r

lea dlevel s wer e foun dt o b e re lated , thu s indicatin g afairl y constan t rat e o f ab

sorption . Th e author s conclude dtha t fo r childre n withexcessiv e lea dabsorptio n th e majo r rout e o f lea dintak e wa s ingestio n o f contaminate ddir t

an d dust. 78

- 7 9 Increase dexcretio n o f 8-aminolevulini c aci dan dcoproporphyrin s wa s observe di n mos t o f thes e cases , an dincrease ddensit y o f bon e metaphyse s wa s observe din fou r children . Bloo dlea dlevel s i n 29 3 Finnis hindividual s age d 1 5 t o 8 0 wer e significantl y correlate dwit hdistanc e o f habitatio n fro masecondar y lea dsmelter. 8 1 Th e geometri c mea n bloo dlea dconcentratio n fo r 12 1 male s wa s 18. 1 figldl; tha t fo r 17 2 female s wa s 14. 3 figldl. I n 5 9 subject s wh o spen t thei r entir e da y a t home , apositiv e correlatio n wa s foun dbetwee n 12-2 0m . Onl y on e o f thes e 5 9 individual s ha dabloo dlea d > 4 0 figldl, an dnon e exceede d5 0 /xg/dl . A weake r

correlatio n wa s obtaine dbetwee n ALA D activit y an ddistanc e fro mth e smelter , thi s bein g du e almos t

entirel y t o th e femal e subjects . Ex

aminatio n o f

ALA D activit y fo r

male s showe dit

t o b e simila r

regardles s o f

distanc e fro mth e smelter . Th e author s speculat e tha t thi s coul db e cause db y othe r lea dexposure s in th e mal e population . Tw o report s fro mth e USS Rdescrib e effect s o f lea di n a n are anea r

asmelter. 828 3 Averag e con centration s o f

lea din ai r

wer e a s hig ha s 4. 1 /xg/m 3 a t adistanc e o f

150 0 m ; pea k

exposure s a t

thi s distanc e reache d9. 7 /ng/m 3

. Neurologica l disturbance s wer e note di n 5 0 percen t

o f th e subject s fro mth e smelte r area , compare dwit h6 percen t i n controls . N o dat a wer e give n o n age , sex , an dtyp e o f disturbances. 8 2 I n alate r study , childre n fro mth e are awer e foun dt o excret e mor e coproporphyri n tha n control s an dals o mor e lead. 8 3 Th e highes t lea dconcentratio n in urin e wa s reporte dt o b e 5 0 /xg/liter . Studie s o f

th e effect s o f

storag e batter y plant s hav e bee n reporte dfro mFranc e an dItaly. 848 5 Th e Frenc hstud y foun dtha t childre n fro ma n in

dustrialize dare acontainin g suc haplan t excrete d mor e AL A tha n thos e livin g in adifferen t area. 8 4 In

crease durinar y excretio n o f lea dan dcopropor phyri awa s foun di n childre n livin g u p t o 30 0 f t fro mabatter y plan t

in Italy. 8 5 Neithe r

stud y gav e dat ao n plan t

emission s o r

lea di n air . Thes e studie s demonstrat e tha t stationar y source s withi n urba n area s d o contribut e t o increase s i n ai r lea dlevels . The y sho w no t onl y tha t

mea n exposur e level s ar e highe r

bu t tha t th e rang e o f

exposure s en countere di n thei r

vicinitie s i s muc hlarge r fo r dail y o r longe r averagin g time s tha n i n th e vicinit y o f mobil e sources . Increase s o f 2 t o 3 /xg/m 3 i n ai r

lea d concentration s hav e bee n associate dwit hhighe r bloo dlea dlevel s in expose dpopulations . Althoug hth e significantl y highe r ai r lea dcon centration s decreas e rapidl y wit hdistanc e fro mth e poin t o f emission , the y contribute , togethe r wit h mobil e emissions , t o th e generall y highe r ai r level s foun di n urba n area s an dthu s t o th e highe r bloo d lea dlevel s foun di n urba n populations . 12.3.1. 3 URBA N POPULATIO N STUDIE S Anothe r grou p o f

studie s dealin g wit hurba n population s examine dai r lea dan dbloo dlea d value s withou t

considerin g th e specifi c source s o f th e lea di n th e air. 2 ' 316

- 41 ' 1 2 Aza r e t al. 3 obtaine d24-h r ai r lea dexposure s fo r

150 male s ove r

a2

- t o 4-wee k perio dusin g persona l samplers . Stud y group s con siste do f 3 0 me n i n eac ho f

5 city-occupatio n catego ries . Th e subject s include dcabdrivers , plan t employees , an doffic e workers . Fro mtw o t o eigh t bloo dsample s wer e obtaine dfro meac hsubjec t dur

in g th e ai r

monitorin g phase . Bloo dlea ddeter

mination s wer e don e i n duplicate . Tabl e 12-2 4 pre sent s th e geometri c mean s fo r ai r lea dan dbloo d lea dfo r th e fiv e groups . Th e geometri c mean s wer e calculate db y EP A fro mth e ra w dat apresente din th e authors ' report. 3 TABL E 12-24 . GEOMETRI C MEA N AI R AN D BLOO D LEA D LEVEL S (/xg/10 0 g ) FO R FIV E CITY-OCCUPATIO N GROUPS 3

(Dat a calculate d b

y EPA )

Grou p Plan t employee s Starke , F L Plan t employee s Barksdale , W l Cabdriver s Philadelphia . PA Offic e worker s Lo s Angeles . C A Cabdriver s Lo s Angeles . CA Geometri c mea n ai rlead . ng/m 3 0.5 9 0.6 1 2.5 9 2.9 7 6.0 2 GS D

2.04 2.3 9 1.1 6 1.29 1.1 8 Geometri c

mea n bloo d lead . ug/10 0 g 15. 4 12. 8 22. 1 18. 4 24. 2 GS D

1.4 1 1.4 3 1.1 6 1.2 4 1.20 Sampl e

siz e 2 9 3 0 3 0 3 0 3 0 Regressio n equation s calculate db y th e author s fo r member s o f

eac ho f th e individua l stud y group s reveale dn o slope s significantl y greate r tha n zero . I n vie w o f th e rathe r

narro w rang e o f

lea dexposure s observe dwithi n th e groups , thi s resul t i s no t surpris

ing . Examinatio n o f

th e slope s fo r

eac hstud y grou p showe dthe y wer e homogeneou s an dthu s coul db e combined . Th e specifi c metho do f combinatio n ca n b e argued , however . Aza r e t al . chos e t o us e dumm y variable s t o represen t

th e differin g intercept s o f th e stud y group s becaus e th e intercept s wer e no t homo

geneous . I n effect , thi s mean s drawin g alin e wit ha poole dslop e o f

0.15 3 throug hth e averag e bloo d lea dconcentration . Th e Teppe r

an dLevin 2 study , describe di n detai l previously , include dbot hai r an dbloo dlea d measurements . Housewive s wer e recruite dfro m "location s i n th e vicinit y o f ai r monitors. " Wome n include dwer e > 1 9 an d< 8 0 year s o f age , ha dn o histor y o f

lea dpoisoning , an dha dno t eate n wil d game . Tabl e 12-2 5 present s th e geometri c mea n ai r an dbloo dlea dvalue s obtaine di n th e study , a s calculate db y EP A fro mth e ra w data . Geometri c mea n ai r lea dvalue s range dfro m0.1 7 t o 3.3 9 12-2 1P.3 1

/xg/m 3 , an dgeometri c mea n bloo dlea dvalue s range dfro m12. 5 (1.31 ) t o 20. 6 (1.33 ) /xg/dl . TABL E 12-25 . GEOMETRI C MEA N AI R AN D BLOO D LEA D VALUE S FO R 1 1 STUD Y POPULATIONS 2 (Dat a calculate d b

y EPA )

Communit y Lo s Alamos , N M Okeana.O H Houston , T

X Port Washington , N Y Ardmore , PA Lombard , I L Washington , D C Rittenhouse , PA Bridgeport , I L Greenwic h Village . N Y Pasadena , C A Geometri c mea n ai rlead . /i g 'm 3 0.1 7 0.32 0.8 5 1.1 3 1.1 5 1.1 8 1.1 9 1.6 7 1.7 6 2.0 8 3.3 9 Bloo d lead./jg'd l

G M 14. 9 15. 6 12. 5 15. 4 18. 0 13. 9 19. 2 20. 6 17. 6 16. 6 17. 5 GS D 1.2 8 1.3 9 1.3 1 1.28 1.3 8 1.2 7 1.2 6 1.3 3 1.2 7 1.2 8 1.3 1 Sampl e

siz e 18 5 156 186 19 6 14 8 146 21 9 136 146 13 9 19 4 Nordma n reporte dapopulatio n stud y fro mFin

land 1 6 i n whic hdat afro mfiv e urba n an dtw o rura l area s wer e compared . Thi s stud y wa s describe din detai l above . Ai r

lea ddat awer e collecte db y sta tionar y samplers . Al l level s wer e comparativel y low , particularl y i n th e rura l environment , wher e acon centratio n o f

0.02 5 /xg/m 3 wa s seen . Urban-subur

ba n level s range dfro m0.4 3 t o 1.3 2 /ig/m 3

. A stud y wa s undertake n b y Tsuchiy ae t al. 4 1 in Toky o usin g mal e policeme n wh o worked , bu t no t necessaril y lived , i

n th e vicinit y o f

ai r samplers . I n thi s study , fiv e zone s wer e established , base do n degre e o f urbanization , rangin g fro mcentra l cit y t o suburban . Ai r

monitor s wer e establishe da t variou s polic e station s withi n eac hzone . Ai r samplin g wa s conducte dfro mSeptembe r 197 1 t o Septembe r

1972 ; bloo dan durin e sample s wer e obtaine dfro m228 3 policeme n i n Augus t

an dSeptembe r

1971 . Finding s ar e presente din Tabl e 12-26 . A consisten t cor relatio n betwee n ai r

an dbloo dlea dmean s fo r th e five zone s i s shown . TABL E 12-26 . MEA N AI R AN D BLOO D LEA D VALUE S FO R

FIV E ZONE S I N TOKY O STUDY 4 1

Ai rlead , jig'm ^ Bloo d lead . ng 100 g 0.02 4 0.19 8 0.44 4 0.83 1 1.15 7 17. 0 17. 1 16. 8 18. 0 19. 7 Goldsmith 4 2 obtaine ddat afo r elementar y schoo l (9

- an d10-year-olds ) an dhig hschoo l student s i n 1 0 Californi acommunities . Lowes t ai r lea dexposure s wer e 0.2 8 /xg/m 3 an dhighes t wer e 3. 4 /xg/m 3

. Fo r boy s i n elementar y school , bloo dlea dlevel s range d fro m14. 3 t o 23. 3 /xg/dl ; thos e fo r girl s range dfro m 13. 8 t o 20 4 figldl

fo r th e sam e rang e o f

ai r lea dex posures . Th e hig hschoo l studen t populatio n wa s mad e u p o f

onl y male s fro msom e o f th e 1 0 towns . Th e ai r lea drang e wa s 0.7 7 t o 2.7 5 /xg/m 3 an dth e bloo dlea drang e wa s fro m9. 0 t o 12. 1 /xg/dl . Fo r th e hig hschoo l student s th e tow n wit hth e highes t ai r lea dvalu e di dno t

hav e th e highes t

bloo dlea dlevel . A furthe r commen t

o n methodolog y pertain s t o th e fac t tha t aconsiderabl e la g tim e occurre dbetwee n th e collectio n an danalysi s o f th e bloo dsamples . 12.3.1. 4 CLINICA LAN D EXPERIMENTA L STUDIE S I N RELATIO N T O AI R LEAD/BLOO D LEA D RATIO S Griffi n an dhi s colleague s undertoo k tw o studie s usin g volunteer s expose din aga s chambe r t o a n ar tificiall y generate daeroso l o f submicron-size dparti

cle s o f lea ddioxide. 8 6 Al l volunteer s wer e intro

duce dint o th e chambe r 2 week s prio r

t o th e initia

tio n o f th e exposure ; th e lea dexposure s wer e schedule dt o las t

1 6 weeks , althoug hth e volunteer s coul ddro p ou t

wheneve r

the y wished . Twenty-fou r volunteers , includin g 6 controls , participate di n th e 10. 9 /xg/m 3 exposur e study . Twenty-on e subjects , in

cludin g 6 controls , participate di n th e 3. 2 /xg/m 3 ex posur e study . No t

al l volunteer s complete dth e ex posur e regimen . Bloo dlea dlevel s wer e foun dt o stabiliz e afte r

approximatel y 1 2 weeks . Amon g I I me n expose dt o 10. 9 /xg/m 3 fo r at leas t 6 0 days , a stabilize dmea n leve l o f 34. 5 ± 5. 1 /xg/d l bloo dwa s obtained , a s compare dwithan initia l leve l o f 19. 4 ± 3. 3 /xg/dl . A

U bu t 2 o f th e 1 4 me n expose dat 3. 2 /xg/m 3 fo r

at leas t 6 0 day s showe dincrease s an da stabilize dleve l o f

25. 6 ± 3. 9 figldl

wa s found , com pare dwithan initia l leve l o f 20. 5 ± 4. 4 /xg/dl . Thi s represente dan increas e o f abou t 4 0 percen t

abov e th e bas e level . Fro mth e dat aTabl e 12-2 7 wa s constructed , whic hshow s th e tim e neede dt o reac hspecifi c bloo d lea dlevel s a t

th e tw o ai r

lea dconcentrations . A s ca n readil y b e see n eve n a t th e lowe r

exposure , i

t take s onl y 7 week s fo r

th e populatio n mea n bloo dleve l t o increas e b y 5 /xg/dl . I n th e article , th e author s describe dbot hth e chemistr y an dparticl e siz e o f th e lea daerosol s generated . I n general , th e aerosol s use din thi s ex perimen t wer e somewha t

les s comple x chemically , a s wel l a s somewha t

smaller , tha n thos e foun din th e ambien t environment . Griffi n e t al., 8 6 however , poin t ou t tha t goo dagreemen t

wa s achieve do n th e basi s o f th e compariso n o f

thei r observe dbloo dlea d 12-2 2TABL E 12-27 . LENGT H O F TIM E NEEDE D FO R MEA N BLOO D LEA D VALUE S T O REAC H SPECIFIE D LEVEL S A TTW O EXPOSUR E LEVEL S Exposur e grou p 1 1 1 2 2 2 Ai rlea d level , jjg' m 10. 9 10. 9 10. 9 3. 2 3. 2 3. 2 Avg . baselin e bloo d lea d level , (tig-'d l Targe t bloo d lea d level , jjg/d l 25 3 0 35 2 5 3 0 35 Tim e neede d t o reac h targe t level , w k 1 t o 2 4 6 7 No t reache d No t reache d 20. 0 20. 0 20. 0 20. 8 20. 8 20. 8 level s withthos e predicte db y Goldsmit han dHex

ter' s equation, 8 7 tha t

is , log 1 0 bloo dlea d= 1.26 5 + 0.243 3 lo g 1 0 atmospheri c exposure . I n contras t

t o th e stud y o f

Griffi n e t

al . tha t approximate s th e exposur e regime n o f environ

mentall y expose dpersons , Keho e studie dlong-ter m exposure s unde r

condition s approximatin g thos e o f occupationall y expose dindividuals. 8 8 Keho e ex pose dasubjec t

t o an ai r lea da s th e sesquioxid e firs t at 7 5 /xg/m 3 the n at

15 0 /xg/m 3

. Definit e increase s in urinar y an dbloo dlea dlevel s emerge dunde r eac h exposure . Ther e appeare dt o b e aplatea u reache din th e bloo dlea dlevel s upo n astead y stat e exposure . Gros s compile ddat afro mlea dbalanc e studie s conducte db y Keho e betwee n 193 4 an d197 2 an d determine dtha t

increase s o f

level s in blood , urine , an dfece s unde r

controlle dclinica l exposur e wer e 0.3 8 /xg/dl , 0.8 8 /xg/day , an d2.5 0 /xg/day , respec tively , fo r

eac hincreas e o f

1 /xg/m 3 i

n ai r lea d levels. 8 9 Th e derivatio n o f

thes e estimate s i s currentl y un know n bu t

wa s base do n th e result s o f ingestio n an d inhalatio n studie s carrie dou t o n 1 6 individual s ove r 21,00 0 person-days . Durin g thi s period , ther e wer e 10 2 stud y period s fo r

th e 1 6 subjects . Non e o f th e subject s experience dharmfu l effect s a s aresul t o f th e lea dexposures , th e highes t o f whic hwer e ap proximatel y 3 0 /xg/m 3 o n a24-h r basi s (ever y othe r da y t o 6 day s pe r

week ) fo r

stud y period s u p t o 62 8 days . Wit hasingl e exception , i n non e o f th e subject s di dth e bloo dleve l excee d4 0 /xg/dl . ' Rabinowit z an dcolleague s hav e conducte d studie s o f

lea dmetabolis mb y stabl e isotope s tha t permi t th e determinatio n o f

blood/ai r

lea drelation

ships. 909 1 I n on e study , asingl e voluntee r wa s con fine din ahospital' s metaboli c researc hwar dfo r a perio do f

10 9 day s fo r

2 3 h r aday. 9 0 H e wa s the n remove dint o a"clean " roo min whic hth e ai r wa s filtere dt o remov e th e particulat e lead . Fo r th e firs t 1 5 day s in th e room , hi s dail y lea dintak e wa s supplemente db y lea daddition s t o th e die t t o com pensat e fo r th e los s o f

ai r lea dintake . A t

th e en do f thi s 15-da y perio dth e dietar y lea dsupplemen t wa s discontinued . H e immediatel y showe dadeclining

bloo dlea dleve l tha t eventuall y reache da minimum . H e the n lef t th e "clean " roo man dhi s bloo dlea dleve l wen t

bac k up . Unfortunately , hi s bloo dlea ddi dno t

stabiliz e afte r

hi s exi t fro mth e "clean " room . A furthe r

repor t present s data , involvin g addi

tiona l volunteers , fro mwhic habloo dt o ai r lea d rati o ca n b e derived. 9 1 Subsequen t t o astabilizin g perio din ametaboli c ward , the y entere dth e filtere d ai r roo man dbloo dlea dlevel s decreased . Th e bloo d lea dlevel s di dstabiliz e upo n exi t fro mth e clea n room . Chamberlai n e t

al. 92

- 9 3 reporte do n studie s in whic hgasolin e containin g tetraethy l lea dlabele d with 203 P b wa s burne di n an interna l combustio n engin e an dth e resultin g tagge dlea dexhaus t aeroso l wa s inhale db y 6 volunteers . Th e lea dcon centration 9 2 wa s typicall y abou t 6 mg/m 3 an dth e tota l particulat e 3 0 mg/m 3

. Th e aggregate s o f parti

cle s abou t

0. 6 fim i

n diamete r

wer e stable : thos e . 5 0.0 1 fim tende dt o coagulate . Exposure s wer e fo r 3 0 mi n o r less , an dth e progres s o f th e lea dthroug hth e bod y wa s monitored . It

wa s foun dtha t

abou t 4 0 per cen t o f th e particle s wa s retained , an dtha t 6 0 per cen t wa s exhaled . Th e lun g clearanc e rat e fo r 203 P b activit y varie dmarkedly , dependin g o n whethe r th e aeroso l wa s irradiated . Th e transferenc e o f activit y t o th e bloo dpeake dat 5 0 h r afte r inhalatio n a t

4 8 percen t o f th e initia l lun g burden . At 7 2 hr . abou t hal f o f th e lea dha dbee n remove dt o bon e an dothe r tissue s an dth e othe r

hal f ha dbecom e attache dt o re dcells . Th e amoun t o f 203 P b in th e bloo dwa s foun dt o declin e withabiologica l hal f lif e o f 1 6 days . Chamberlai n e t

al . the n extrapolate dthes e high

level , short-ter mexposure s t o longe r ter mones . Th e followin g formul aan ddat awer e use dt o calculat e a blood-to-ai r

leve l ratio : 12-2 3P.3 3

[T |/2 ] [%Deposition ] [%Absorption ] [Dail y

ventilation ] [Bloo dvolume ] [0.693 ] where : a = bloo dt o ai r lea drati o biologica l hal f

lif e (12-7 )

1 1/ 2 Dat ause dwere : 1 . Airborn e leve l = 1 /xg/m 3 2 . Exposur e = 2 4 hr/da y 3 . Dail y ventilatio n = 15m 3 /da y 4 . % Depositio n =40 * 5 . % Absorptio n = 50 * 6 . Bloo dvolum e = 540 0 ml 'Thes e value s wer e determine d experimentall y in this study ; al l other s are authors ' assumptions . Usin g th e abov e equatio n an dvalues , Cham

berlai n e t

al. 9 3 obtaine darati o o f 1.2 , i n contras t

t o avalu e o f

1. 1 reporte di n a n earlie r report, 9 2 wher e slightl y differen t

assumption s wer e made . I n thi s earlie r report, 9 2 dat afro mKehoe 8 8 an dWilliam s e t al. 9 4 wer e use di n asimila r manne r t o calculat e ratio s o f 1. 1 an d1.1, respectively . I t i s interestin g t o not e th e differenc e i n th e ratio s calculate db y Gross 8 9 an dChamberlai n e t al. 9 2 fro mth e Keho e data . However , th e extrapolatio n o f Chamberlai n e t al . o f th e short-ter mt o long-ter mexposur e i s i n clos e agreemen t

wit hth e result s o f

Keho e an do f William s e t

al. , a s Chamberlai n e t al . calculate d them . Chamberlain' s ratio s hav e bee n recalculate db y Bridbord 9 5 o n th e basi s o f amor e activ e person' s dail y ventilatio n o f

2 0 m 3

. This , h e states , woul d yiel darati o o f

1. 6 /xg/d l fo r

eac h1 /xg/m 3 o f

ai r lea d exposure . 12.3.1. 5 BLOOD/AI RLEA D RELATIONSHIP S Summarizatio n o f

th e relationshi p betwee n lea di n ai r an dlea di n bloo drequire s th e consideratio n o f severa l distinc t

line s o f evidence . Thes e include : th e minima l ai r

lea dconcentratio n a t

whic hbloo dlea d level s ar e first

elevated , th e for man dmagnitud e o f th e relationship , th e proportio n o f th e populatio n whos e bloo dlea dleve l exceed s an y specifi c valu e a t an y give n ai r

lea dconcentration , an dwhethe r th e for mo r magnitud e o f

th e relationshi p varie s de

pendin g o n whethe r

th e ai r lea dexposur e i s increas

ing , remainin g constant , o r decreasing . O n th e first

point , onl y afew studie s hav e suffi

cientl y precis e estimate s o f ai r lea dexposure s t o per mi t thi s calculation , namel y Yanke l e t al. 1 an dAza r e t al. 3 EP A use dWilliam' s 9 6 tes t o n th e dat afro m bot hthes e studie s t o determin e th e ai r lea dlevel s a t whic hbloo dlea dlevel s wer e foun dt o b e signifi

cantl y highe r

tha n th e geometri c mea n bloo dlea d level s o f th e group s expose dt o th e lowes t ai r lea d level , whic hthu s serve da s controls . William' s tes t i s amultipl e compariso n tes t designe dt o mak e suc h comparisons . Fo r dat afro mth e Yanke l e t al . study, 1 EP A poole dth e lowes t

tw o ai r lea dexposur e area s ( V an dVI ) t o for mth e contro l group . Th e tes t showe dtha t

are aI V wa s th e first , i n th e ordere ddata , tha t

showe dsignifican t

elevatio n o f bloo dlea dvalues . Th e correspondin g ai r lea dcon centratio n fo r

thi s are awa s 1. 7 /xg/m 3

. EPA , usin g thi s sam e tes t fo r th e Aza r

e t al . study, 3 showe dtha t

bloo dlea dvalue s fo r

th e Phila

delphi acabdriver s wer e significantl y differen t fro m tha t fo r th e poole dStark e an dBarksdal e plan t employee s tha t

constitute dth e contro l population . Bloo dlea dvalue s fo r th e Lo s Angele s offic e worker s wer e als o significantl y highe r tha n thos e o f contro l populations . Th e correspondin g ai r lea dex posure s wer e 2. 6 an d3. 1 /xg/m 3

. respectively . Th e clinica l stud y o f

Griffi n e t

al. 8 6 provide s dat a tha t suppor t th e result s o f

th e EP A analysi s o f

Aza r e t al. 3 data . Th e dat asho w tha t individual s expose d t o 3. 2 /xg/m 3 ha dadefinit e increas e i n thei r bloo d lead s a s aresul t

o f thi s exposure . Thus , th e availabl e dat aar e consisten t a s t o th e valu e o f ai r lea dconcentratio n a t

whic hbloo dlea d level s begi n t o increase . Th e Yanke l e t al . data 1 demonstrate dthi s increas e a t 1. 7 ,u.g/m 3 ; th e Aza r

e t al . data, 3 a t

2. 6 /xg/m 3

. Thes e result s ar e no t incon

sisten t becaus e th e Aza r

e t al . stud y di dno t

hav e a populatio n expose dt o aleve l o f ai r lea dbetwee n 1 an d2. 6 /xg/m 3

. Th e derivatio n o f

th e functiona l relationshi p be

twee n ai r

lea dexposur e an dbloo dlea dlevel s ha s technica l difficultie s becaus e th e tru e for mo f thi s relationshi p i s no t

linear . N o matte r

wha t th e difficult y i n makin g thi s assessmen t is , th e for mo f th e relationshi p i s extremel y importan t becaus e i t

i s use dt o determin e th e effec t o f achang e i n th e bloo d lea dlevel s a s afunctio n o f th e ai r lea dvalues . Som e studies , b y th e ver y natur e o f thei r design , onl y permi t

calculatin g th e rati o betwee n achang e i n bloo dlea dan dassociate dchang e i n th e ai r lea dcon centration . Fo r

thes e situations , th e calculate drati o ca n b e considere da s a n estimat e o f th e averag e rati o ove r th e rang e o f

th e ai r lea dlevel s encountered . Fo r thos e studie s i n whic hafunctiona l relation

shi p ca n b e derived , thi s rati o ca n b e estimate dfo r a give n ai r

lea dconcentratio n b y evaluatin g th e derivativ e o f

th e functiona l relationshi p a t tha t 12-2 4

### value . Thi s rati o i s subjec t t o considerabl e chang e over th e rang e o

f ai r leadlevel s encountered , de

pendin g on th e for

mo f th e relationshi p that

wa s fitted . W e hav e chosen , wherever

possible , t o us e th e author' s ow

n mode l fo

r th e relationship. Th e earlies t

attemp t t o us e epidemiologica l dat a t o calculat e ablood-to-ai r leadrelationshi p wa s mad e b y Goldsmithan dHexter. 8 7 

### A linea r regres sion equatio n of

th e logarith mo

f th e bloo dlead level on th e ai r

lea dlevel wa s performe do n dat a fro mth e Three-City Study. 4 0 

### Dat afro mKehoe' s ob

servation s on 4 individual s experimentall y expose d t o 1 0 an d15 0 /xg/m3 

### i

n apattern equivalen t

t o anor ma l wor k exposure wer

e foundt o fi

t th e equation . Th e slop e o

f thi s lin e wa s no t

significant

belo w 2 figlm 3 

### o f ai r exposure , possibly becaus e fe w observa

tion s wer e availabl e i

n th e Three-City Study belo w that level . Th e derive dslop e o f th e regressio n lin e suggest s a n increas e o

f 1. 3 /xg/d l fo r eachmicrogram o f ai r lead . Aza r e t al. 3 

### use dalog-lo g mode l t o fi t thei r data ; th e data , a s well a s th e regressio n line , ar e presente d i n Figure 12-8 . Th e slopes , that is , th e ratios , wer

e calculate dfromth e equation , lo g Pb- B = 1.255 7 + 0.15 3 (lo g Pb-A) , a

t th e fou r air leadvalue s shown i n Tabl e 12-28 . Thes e slope s range dfro m2. 6 at a n ai r leado f 1.0 /xg/m3 

### t o 0. 7 a

t a n ai r leado f 5. 0 /xg/m3



### . I t i s importan t

t o not e tha t

al l fou r ai r lead concentration s of

interes t ar e well withi n th e rang e o f th e ai r level s observed .

4 0

2 0

1 0 - 1

• ' _—^— 7~ * * . •* • l 1

L-^-r~ • *. . 9 •

1 1

• ' " ' »

1 1 1 1

. °

. O LO S ANGELE S OFFIC E WORKER S A LO S ANGEt-E S CA B DRIVER S • BARKSDALE . WISCONSI N 7STARKE , FLORID A • PHILADELPHI A CA B DRIVER S 1 1 1 TOTA L AI R LEAD , ng/ m Figur e 12-8 . Bloo d lea d versu s ai r lea d fo r urba n mal e workers. 3

TABL E 12-28 . ESTIMATE D BLOO D LEA D T O AI R LEA D RATIO S FO R FOU R AI R LEA D CONCENTRATION S

Stud y Epidemiologica l Azar a Tepper-Levin b Nordman b Nordman " Fugas b Johnson b Johnson ^ Tsuchiya b Goldsmith b Goldsmith b Yankel-vo n Lindern a Chamberlains-William s Daines b Clinica l Griffin " Griffin " Rabinowitz " Gross 0 Chamberlain 0 Chamberlainc-Keho e Populatio n Adul t male s Adul t female s Adul t male s Adul t female s Adult s Adul t male s Adul t female s Adul t male s Childre n male s Childre n female s Childre n Adult s Blac k female s Adul t male s Adul t male s Adul t male s Adult s Adult s Adult s Sampl e siz e 14 9 190 8 53 6 47 8 33 0 6 4 10 7 59 1 20 2 20 3 87 9 48 2 (unknown ) 1 1 @10. 9 14 ® 3. 2 2 (21,00 0 person-days )

7 5 1. 0

2.5 7 0.8 7

1.1 6 Rati o a t

ai rlea d concentrations , 2. 0 1.4 3 0.9 2

1.2 1 u. g/m ' 3. 5

0.8 9 1.0 0 (0.42) ° (0.11 ) (2.64 ) (0.80 ) (0.60 ) (3.84 ) (2.30 ) (1.70 ) 1.2 7 (1.10 ) (2.30 ) (1.40 ) (1.65 ) (1.7,2.5 ) (0.38 ) (1.20 ) (1.10 ) 5. 0

0.6 6 1.0 8

1.3 7

a Authors ' regressio n equatio n evaluate d a t specifi cai rlead . b EPA calculation . cAuthors ' calculations . d Ratio s presente d i n parenthese s ar e no t calculate d fro m an yregressio n equation . 

### 12-2 5P.3 5

On e o f th e authors , Snee, 5 0 ha s sinc e reanalyze d th e dat ausin g amor e complicate dmode l fo r th e relationship . Hi s newe r mode l attribute s les s o f th e increas e in bloo dlea dt o ai r lea dexposure s an d mor e t o geographi c are adifferences . Th e improve

men t in fit b y us e o f

thi s newe r

mode l i s insignificant . Furthermore , i n th e ne w model , th e are adifference s ar e correlate dwithth e ai r lea ddifferences . Fo r thes e reasons , th e origina l mode l i s believe dt o b e mor e appropriat e fo r

estimatin g th e tota l effec t o f ai r lead . Yanke l e t

al. 1 use dalog-linea r

mode l (Equatio n 12-6 ) t o fit

thei r data . Th e slope s o f

th e fou r ai r lea d value s show n in Tabl e 12-2 8 wer e calculate dfro m thi s equation . Thes e range dfro m1. 2 a t a n ai r lea d leve l o f 1. 0 /xg/m 3 t o 1. 4 at

a n ai r lea do f 5. 0 yxg/m 3

. Again , al l ai r

lea dconcentration s wer e withi n th e rang e o f th e data . On e assumptio n inheren t in th e calculatio n o f

th e regressio n o f

bloo dlea do n ai r

lea dusin g standar d leas t square s i s tha t

th e ai r lea dvalue s hav e bee n measure dwithn o error . Unfortunately , thi s assump tio n i s no t

correct . Obviously , th e monitore dai r lea d value s ar e no t

th e exac t

value s inhale db y th e sub

ject s in th e exposur e area . Th e effec t o f measuremen t erro r in th e independen t

variabl e i s discusse db y Kendal l an dStuart. 9 7 I n general , th e calculatio n regressio n coefficient s ar e underestimate s o f th e tru e values . I f eithe r th e erro r

i n th e dependen t

variable , o r th e erro r

in th e independen t

variable , o r

th e rati o o f th e tw o error s wer e known , the n improve desti

mate s coul db e calculated . Th e Yanke l e t

al . study 1 give s sufficien t informa

tio n t o estimat e th e effec t o f thi s problem . Th e author s assigne d1 o f

3 3 differen t

estimate dex posur e level s t o eac hindividua l in th e study . I f th e withi n leve l variance s o f bloo dlea dvalue s ar e poole dfo r

thes e 3 3 levels , th e resul t i s apoole d GS D o f 1.28 . Usin g th e valu e o f 1.2 8 fo r th e erro r

i n th e dependen t

variable , th e regressio n coefficien t o f 0.04 1 reporte db y Yanke l an dvo n Linder n become s 0.052 . Thi s adjustmen t increase s th e estimate d bloo dlea dt o ai r

lea drati o fro m1.2 1 t o 1.44 a t 2 figlm 3 an dfro m1.3 7 t o 1.6 9 at 5 Mg/m3

- Thi s proble mmay exis t in som e o f

th e othe r studies , bu t

it i s no t aseriou s proble min tw o o f th e othe r mor e importan t

studies . I n th e Aza r

study, 3 persona l sampler s wer e used , s o tha t individua l ex posure s wer e measure dmor e accuratel y tha n i n an y othe r epidemiologi c study . I n th e Griffi n stud y th e ai r lea dlevel s wer e controlle dextremel y closely , s o tha t ther e wa s almos t

n o variatio n i n th e exposur e value . Th e reanalysi s o f th e Tepper-Levi n study 2 a s re porte db y Hasselbla dan dNelson 2 2 wa s use dt o esti

mat e th e relationshi p o f ai r lea dt o bloo dlea dlevels . A log-linea r

mode l wa s use dtha t

allowe dfo r

ag e an dsmokin g differences , a s wel l a s th e ai r lea dex posure . Thi s formo f

th e mode l wa s chose n becaus e i t gav e abette r

fit t o th e dat atha n di dth e log-lo g model . Th e slope s wer e calculate dfro mth e log

linea r mode l a t

th e fou r ai r lea dvalue s show n in Ta

bl e 12-28 . Thes e slope s range dfro m0. 9 a t a n ai r lea do f 1. 0 figlm 3 t o 1. 1 a t

a n ai r lea do f 5. 0 /xg/m 3

. Th e ai r lea dvalue s onl y range dfro m0. 2 t o 3. 4 /u.g/m 3 , however , Daine s e t

al . reporte dtw o studie s examinin g variation s in bloo dlea dratio s withdistanc e fro m bus y highways. 5 2 Th e studie s wer e conducte di n Camden , Ne w Jersey , an dinvolve dblac k females . Onl y on e o f

thes e studie s ca n b e use dt o determin e th e bloo dlead/ai r

lea drati o becaus e n o ai r lea ddat a wer e reporte dfo r

th e othe r

study . I n thi s study , bloo dlea dievel s o f

blac k female s livin g in resi

dence s tha t

wer e 3.7,38.1 , an d121.9 mdistan t fro m th e highwa y wer e determined . Yearl y mea n ai r an d bloo dlea dlevel s fo r

thes e thre e group s ar e pre sente di n Tabl e 12-29 . Fro mthes e value s arati o ma y b e calculate da s follows : 23.1-17. 6 rati o = A ,,, ~ ~A = 2. 3 fo r th e tota l population . 4.60-2.2 4 Usin g asimila r

calculation , housewive s wer e foun d t o hav e arati o o f

3 . TABL E 12-29 . YEARLY MEA N AI R AN D BLOO D LEA D LEVEL S O F BLAC KFEMALE S I N RELATIO N T O DISTANC E O F RESIDENC E FRO M A BUS Y HIGHWA Y Stud y are a Are a A Area B Area C I n Yugoslavia , Fuga s e t al . i n th e stud y describe d earlier, 6 9 estimate dth e weekl y time-weighte dai r lea dexposure s o f

eigh t populatio n groups . Th e esti

mate s wer e base do n ai r lea dvalue s monitore dat variou s location s an destimate dproportion s o f tim e th e individual s spen t

at thos e locations . Th e time

weighte dexposur e estimates , sampl e sizes , an d bloo dlea dlevel s fo r

thi s stud y wer e presente d earlie r (Tabl e 12-22) . A weighte dregressio n analysi s wa s chose n fo r thes e dat abecaus e th e sam pl e size s o f

th e custom s officer s an dpoliceme n varie dfro mthos e fo r

th e othe r

groups . Th e rang e o f ai r lead s wa s fro m0.07 9 t o 3. 0 ,ug/m 3

. Th e resultin g slop e i s 2.64 , an di s presente di n Tabl e 12-28 . Distanc e fro m highway , m 3. 7 38. 1 121. 9 Ai rlead .

Mg/m ' 4.6 0 2.4 1 2.2 4 Bloo d lea d

jjg/l00 g 23. 1 17. 4 17. 6

12-2 6P.3 6

Snee 5 0 ha s criticize dth e inclusio n o f th e streetca r driver s becaus e o f

difference s in socia l statu s an d habit s fro mth e othe r

groups . Th e effec t

o f removin g thes e subject s woul db e t o reduc e th e calculate d slope . Thi s grou p wa s no t remove dbecaus e th e ai r lea dexposur e wa s mor e precisel y estimate dtha n in othe r studies . Dat ao n Toky o policeme n reporte db y Tsuchiy ae t al. 4 1 an ddiscusse din detai l previousl y i n thi s chapte r ma y als o b e use dt o calculat e aslope . Unfor

tunately , th e slop e tha t

i s derive dca n onl y b e looke d upo n a s confirmator y evidenc e an dno t a s additiona l evidenc e becaus e o f

th e tim e differenc e betwee n samplin g th e ai r

an dsamplin g th e blood . Anothe r possibl e complicatin g facto r i s th e rural-urba n gra dien t tha t parallel s th e ai r

lea dconcentrations . Weighte dregressio n analysi s wa s use do n th e bloo d an dai r lea ddat areporte din Tabl e 12-26 . Th e esti

mate dslop e i s 3. 8 an di s recorde din Tabl e 12-28 . Th e observe drang e in ai r lea dconcentration s wa s 0.02 4 t o 1.15 7 Mg/m 3

. Fro mth e Johnso n e t

al . stud y in California, 6 esti

mate s o f th e rati o betwee n bloo dan dai r lea dlevel s ca n b e derived . Becaus e o f analysi s problem s en countere din th e bloo dlea ddetermination s o f children , it

wa s decide dtha t

avali destimat e coul d no t b e derived . Therefore , onl y dat afo r adult s wil l b e treate dhere . I t

wa s decide dt o poo l th e dat afo r adult s an dpresen t

separat e ratio s fo r

male s an d female s age d1 7 an dabove . Geometri c mea n bloo d lea dlevel s wer e use din th e calculatio n becaus e th e bloo dlea ddat awer e foun dt o follo w alog-norma l distribution . Fo r males , th e poole dgeometri c mean s wer e 15. 5 an d11. 0 figldl

fo r Lo s Angele s an dLancaster , respectively . Fo r

females , th e correspondin g value s ar e 12. 1 an d8. 4 figldl. Th e rati o wa s calculate da s follow s fo r

males : rati o = (15.5-11.0)/(6.3-0.6 ) = 0.8 . Th e rati o fo r

female s wa s 0.6 . Thes e value s ar e tabulate din Tabl e 12-28 . Nordma n in hi s doctora l dissertation 1 6 reporte d o n bloo dan dai r

lea dlevel s fo r

severa l population s i n Finlan d(Tabl e 12-30) . Becaus e o f th e larg e varia

tio n i n th e sampl e size s fo r thes e populations , EP A calculate daweighte dregressio n equation . Th e slop e o f th e equatio n wa s estimate dfo r bot hmale s an d female s separatel y an di s 0. 4 an d0.1 , respectively , a s presente di n Tabl e 12-28 . I t shoul db e note dtha t th e rang e o f

ai r lea dconcentration s covere db y thi s stud y wa s 0.02 5 an d1.3 2 Mg/m 3

. Dat afro mGoldsmith 4 2 o n elementar y an dhig h schoo l childre n i n anumbe r o f Californi atown s ca n als o b e use di n th e calculatio n o f th e slopes . EP A ha s TABL E 12-30 . BLOO D AN D AI R LEA D LEVEL S B Y SE X I N FINNIS H POPULATIO N STUDY TM

Grou p Pertumma a Pyhajaru i Suburba n Downtow n Policeme n Stree t sweeper s Ai rlead , Mg/m 3 0.02 5 0.02 5 0.74 0.9 0 1.3 2 1.3 2 Mal e bloo d lead ,

N 24 3 — 37 14 2 2 8 8 6 ixg/d l Av g 12. 1 — 10. 6 11. 4 13. 5 13. 3 S D 4. 5 — 2. 8 3. 3 2. 8 4. 1 Femal e bloo d lead ,

N 25 6 9 3 8 1 3 7 — 1 1 /jg/d i Av g 9. 6 8. 6 9. 7 8. 5 — 10. 4 S D 3. 5 2. 5 2. 6 2. 0 — 3. 0 separatel y analyze dth e ra w dat afro mthi s stud y fo r elementar y schoo l male s an dfemales . Th e result s o f thes e analyse s sho w ratio s o f 2.3 0 an d1.70 , respec tivel y (Tabl e 12-28) . Chamberlai n e t

al. 9 2 analyze dth e dat ao f William s e t

al. 9 6 o n occupationall y expose dperson s usin g persona l monitors . Chamberlai n adjuste dth e occupationa l exposure s t o 24-h r exposure s b y calculatin g th e elevatio n in bloo dlea dfro manon expose dpopulation . H e calculate daslop e o f 1.1 . Clinica l studie s als o provid e dat ausefu l in quan titatin g th e relationshi p betwee n bloo dan dai r lead . Griffi n e t

al., 8 6 i n thei r

clinica l stud y o f

th e larges t numbe r o f subject s t o date , expose dindividual s t o 2 level s o f ai r lea dconcentrations , 10. 9 an d3. 2 Mg/m 3

. Th e stud y design , it wa s believed , preclude s fittin g a n overal l equatio n t o thes e data , an dasepa rat e calculatio n o f

arati o i s presente dfo r

th e tw o ex periments . I n bot hexperiments , th e backgroun dai r lea dlevel s wer e estimate dt o b e 0.1 5 Mg/m 3

- 1 ° tn e 3. 2 Mg/m 3 ai r

lea dexposure , th e me n increase dthei r mea n bloo dlea dlevel s fro m20. 5 t o 25. 6 figldl. Thi s yield s arati o o f

1.6 5 (25.6-20.5)/(3.2-0.15) . Th e 10. 9 Mg/m 3 ai r

lea dexposur e resulte di n a n in

creas e o f bloo dlea dlevel s fro m19. 4 t o 34. 5 figldl. Thi s give s arati o o f

1.4 0 (34.5-19.4)/ ( 10.9-0.15) . Thes e value s ar e show n i n Tabl e 12-28 . Chamberlai n e t

al. 9 2 reanalyze dth e Keho e result s b y adjustin g th e 37.5-h r exposure s pe r

wee k t o a24

- h r equivalent . The y use ddat afro m5 subject s whos e 24-h r equivalen t

exposure s range dfro m0. 6 t o 73. 5 Mg/m 3

. Th e calculate dratio s range dfro m0. 6 t o 2.0 , wit ha n overal l mea n o f 1. 1 fo r th e data . I n contras t

t o th e analysi s o f

Kehoe' s wor k

b y Chamberlai n i n whic ha1. 1 rati o wa s calculated , Gross 8 9 report s arati o o f 0.3 8 fo r thes e data . A t

thi s time , n o detail s ar e availabl e concernin g hi s methods . Therefore , th e apparen t discrepanc y be

twee n thes e tw o analyse s canno t b e evaluated . Chamberlai n e t

al., 92 * 9 3 a s discusse dearlier , calculate dratio s o f

1. 1 an d1. 2 base do n th e ex 12-2 7P.3 7



### trapolatio n o

f ashort-termexposure t o along-ter m one . Th e calculatio n involve s anumber o f experi

mentall y determine da s well a s assume dnumbers . A s describe dpreviously , Rabinowit z e t al. 9 1 

### studie dthre e individual s fo r metaboli c change s i

n bloo dleada s afunctio n o f change s i n th e ai r lead concentration . In contras t t o th e othe r

clinical studie s describe dwherei n ai r leadlevel s were in

creased , i n thi s study th e subject s wer e place di

n a "clean room " i

n whichth e ai r

wa s filtered . Thi s study , therefore , pertain s t o th e situatio n i n which th e ai r leadconcentratio n ha s decreased . Th e bloo d leadlevel s were determine dfro mth e stabilize d mea n bot hwhe n th e subjec t

was breathin g normal a s well a s filtere dair . On e o f th e me n di dno t hav e a stabilize dbloo dleadafte r returnin g t o breathin g normal air ; therefore , he coul dno t b e usedi n deter

minin g th e ratio . Th e relevan t dat afo r calculatin g th e rati o ar e include di

n Tabl e 12-31 . TABL E 12-31 . BLOO D AN D AI R LEA D DATA

FRO M CLINICA L STUDY 9 1

Subjec t D E Estimate d

Norma l air , J J g/m 3 0.9 1 0.9 1 ai r lea d

Filtere d air , li g/m 3 0.07 2 0.07 2 Bloo d lea d

Norma l air , /»g/l00 g 20. 2 16. 3 Filtere d air ,

Mg/10 0 g 18. 8 14. 2 

### Th e calculatio n fo

r subjec t D was don e a s follows : rati o = (20.2-18.8)/(0.91-0.072 ) = 1.7 . Th e calculatio n fo

r subjec t E result s i

n arati o o

f 2.5 . Only on e dat ase

t (Aza r e t al. 3 

### ) i s availabl e o

n whicht o estimat e adose-respons e relationship , that is , th e proportio n o

f apopulatio n exceedin g a specifiedbloo dleadlevel for an y specifi c exposure . Th e reason s fo

r th e paucit

y o f dat aar e twofold : (1 ) acces s i s neede dt o th e ra

w dat aand(2 ) th e exposure dat ashoul db e relativel y precise . Th e regressio n equatio n fo r th e Aza r study 3 

### ha s alread y been discussed . Th e mea n squar e erro r (MSE ) abou t

thi s equatio n was calculate dfo r al l fiv e area s combined . Fro mth e MSE , estimate s o f th e percentag e o

f th e populatio n exceedin g agiven bloo dleadlevel fo

r agiven ai r

leadlevel ar e given by : Percen t= Plog, 0 (bloo d lead ) - 1.2257-0.153 1 log | 0 (ai rlead) 1 100 

## f 

## r l ( 

# HMSE" 2 

# ] } where : N(x ) i s th e cumulativ e normal integral o f a standar dnorma l variabl e up t o th e poin t x . Thes e percentage s ar e given i

n Tabl e 12-3 2 fo

r arang e o

f ai r leadvalues . Thes e tabulate dpercentage s ma y no t b e represen tativ e o f th e general population , sinc e the y ar e base d on asingl e study o

f 149 subjects . They ar e presente d becaus e they ar e th e bes t estimate s availabl e o

f a dose-respons e relationship. TABL E 12-32 . ESTIMATE D PERCENTAG E O F POPULATIO N EXCEEDIN G A SPECIFI C BLOO D LEA D LEVE L I N RELATIO N

T O AMBIEN T AI R LEA D EXPOSURE *

Percen t exceedin g bloo d lea d leve l ol : r lead , ig/m 3 0. 5 1. 0 1. 5 2. 0 2. 5 3. 0 3. 5 4. 0 4. 5 5. 0 6. 0 7. 0 8. 0 20. 0 ug/d l 15.2 2 26.2 0 34.1 2 40.2 3 45.1 5 49.2 3 52.6 9 55.6 7 58.2 7 60.5 7 64.4 5 67.6 3 70.2 8 30. 0 f<g/d i 0.5 9 1.6 7 2.8 8 4.1 2 5.3 5 6.5 7 7.75 8.9 0 10.0 1 11.0 9 13.1 6 15.1 0 16.9 2 40. 0 Mg/d l 0.0 2 0.0 7 0.1 6 0.2 6 0.3 8 0.5 1 0.6 6 0.8 1 0.9 7 1.1 4 1.4 8 1.8 3 2.2 0

a Dat a derive d Iro m th e equatio n o l Aza r et al. 3 

### Th e las t element i n definin g th e relationshi p be

tween leadi

n bloo dan dleadi

n ai r i s adiscussio n o

f th e effec t that varyin g th e concentratio n o f leadi n ai r ha s on th e bloo dlea

dlevels . Mos t

o f th e dat a previousl y presente dhav e deal t wit hsteady stat e o r increasin g ai r

leadconcentrations . Thi s sectio n will summariz e th e result s of

studie s showin g th e effect of decreasin g th e concentratio n o f leadi n ai r on th e bloo dleadlevel s o

f huma n populations . Rabinowit z et

al.' s study 9 I

### provide s estimate d ratio s fo r tw o subject s unde r

carefull y controlle d condition s who experience dadecreas e i n thei r ai r leadconcentrations . Fo r

th e tw o subjects , a1 Mg/m 3 

### decreas e i n ai r leadlevel s resulte di

n a2 figllOO g decreas e i n bloo dlea

dlevels . Baker 9 8 

### presente ddat at o th e EPA Scienc e Ad

visor y Boardshowin g decrease s i n bloo dleadlevel s i n th e vicinit

y o f a n Idah o smelter

between 197 4 an d 197 5 (fabl e 12-33) . Informatio n fro mal l study area s combine dindicate dthat bloo dleadlevel s had decrease db

y 2. 3 figldl

fo r each1 Mg/m

3 

### reductio n i n ai r lead . Thi s sam

e investigato r

provide daddi

tional informatio n i

n aseparat e communicatio n t o EPA showing that , whe

n analyse s wer

e limite dt o childre n o

f nonsmelte r

workers , bloo dleadlevel s decrease d2. 0 figldl

i n al l study area s fo

r eac h decreas e o

f 1 figlm 3 

### o

f ai r lead . I f th e analyse s in

clude donl y thos e childre n of nonsmelte r

worker s expose dt o ai r

leadlevel s rangin g fro

m0. 5 t o 1 0 12-2 8Mg/m 3 , bloo dlea dlevel s decrease d1. 3 figldl fo r eac huni t

decreas e i n ai r

lea dan dals o showe da highe r rati o a t greate r ai r lea dconcentrations . Fro m thes e analyses , i t

seem s apparen t

tha t asingl e rati o canno t describ e th e dat afro mthi s study . TABL E 12-33 . COMPARISO N O F BLOO D LEA D LEVEL S I N CHILDRE N WIT H AI R LEA D LEVEL S FO R 1974 AN D 1975

(EP A analyses )

Stud y are a 1 2 3 4 Bloo d lea d levels ,

1974 6 9 4 9 3 6 3 3 II

g/d l 1975 4 6 3 8 3 2 2 7 Diff . 2 3 1 1 4 5 A i

1974 1 8 1 4 6. 7 3. 1 lea d levels ,

Ii g/m 3 197 5 10. 3 8. 6 4. 9 2. 5 Diff . 7. 7 5. 4 1. 8 0. 6 Pb- B diff. /

Pb- Adiff . 3. 0 2. 0 2. 2 8. 0 Dat afro mAngl e an dMclntire' s studies 737 6 i n Omah aals o provid e dat ai n thi s regard . The y foun d bloo dlea dlevel s o f

urba n children , age d6 t o 18 , t o consistentl y decreas e durin g th e year s 197 0 t o 1973 . Thi s decreas e wa s almos t 1 0 figldl

acros s al l stud y groups . Furthermore , thi s decreas e ha s bee n foun d t o b e closel y correlate dwithadecreas e in ai r lea d fro mabou t

1. 5 t o les s tha n 0. 5 Mg/m 3

. I n areanalysi s o f th e ful l dat abase , Angl e ha s calculate da n overal l equatio n o f

Pb- B = 10.0 4 (Pb-A ) + 17.06 , r = 0.95 . Dat afro mNe w Yor k

Cit y analyze db y HUD 3 8 an ddescribe di n detai l i n th e demographi c variabilit y sectio n o f

thi s chapte r

ma y als o provid e supportiv e dat afo r

th e notio n tha t

adecreas e i n bloo dlea dleve l i s associate dwithdecrease dai r lea d exposure . I n th e Ne w Yor k lea dscreenin g progra m geometri c mea n bloo dlea dvalue s hav e bee n note d a s decreasin g consistentl y fro m197 0 t o 1976 . Dur

in g thi s time , som e change s occurre di n th e numbe r o f childre n sampled , s o tha t th e mor e recen t

year s hav e fa r fewe r dat apoint s tha n th e earlie r years . N o significan t

brea k in th e tren dwa s observe da s th e chang e i n sampl e siz e wa s noted . Dat afro mon e Hi

Vo l ai r statio n provide dcontinuou s ai r lea dvalue s ove r thi s perio di n Ne w Yor k City . Th e ai r

lea d value s measure dthere , no t reall y representativ e o f th e exposur e o f

th e childre n bein g studied , hav e bee n followin g asimila r pattern . I t

i s als o interestin g t o not e tha t

lea di n gasolin e i n Ne w Yor k Cit y wa s als o bein g reduce ddurin g thi s period . Th e quantitativ e estimate s provide dfro mth e thre e studie s discusse dsho w decreasin g ai r lea dcon centration s var y fro maminimu mo f 1. 3 t o 8 o r

1 0 figldl. Thes e dat asugges t tha t agreate r

rati o ma y hol dfo r

decrease s in ai r

lea dtha n fo r

stead y stat e o r increasin g exposures . I n summary , i n al l quantitativ e studie s presented , apositiv e relationshi p betwee n bloo dlea dan dai r lea dha s bee n found . Th e for man dmagnitud e o f th e relationship , however , ha s no t bee n foun dt o b e con stan t bu t varie s in th e studie s reviewed . Tabl e 12-2 8 summarize s th e quantitativ e estimate s derive dfro m th e revie w an danalysi s o f th e literature . I n general , th e dat asho w tha t th e bloo dlea dt o ai r lea drati o i s no t

constan t ove r th e rang e o f

ai r ex posur e encountere d(i t varie s in mos t

studie s be

twee n 1 an d2) , tha t

male s appea r

t o hav e highe r ratio s tha n females , an dtha t childre n hav e aslightl y highe r rati o tha n adults . Also , th e dat asugges t tha t mor e attentio n shoul db e give n t o studie s o f decreas

in g ai r lea dconcentration s in tha t th e ratio s derive d fro msuc hstudie s appea r highe r tha n thos e o f

stead y stat e o r increasin g exposures . 12.3. 2 Soi l an d Dus tExposure s Th e relationshi p o f

exposur e t o lea dcontaine di n soi l an dhousedus t

an dth e quantit y o f lea di n humans , particularl y i n children , ha s bee n th e sub

jec t o f scientifi c investigatio n fo r som e time. 7 8 "- 1 0 5 Dugga n an dWilliams 10 5 hav e recentl y publishe da n assessmen t

o f th e ris k o f increase dbloo dlea dresult

in g fro mth e ingestio n o f lea din dust . Som e o f

thes e studie s hav e bee n concerne dwithth e effect s o f suc h exposures: 789910 2 other s hav e concentrate do n th e mean s b y whic hth e lea din soi l an ddus t become s availabl e t o th e body. I0310 4 I n on e o f

th e earlies t

investigations , Faire y an d Gra y conducte daretrospectiv e stud y o f lea d poisonin g case s in Charleston , Sout hCarolina. 9 9 Two-inc hcor e soi l sample s wer e collecte dfro m17 0 randoml y selecte dsite s in th e cit y an dwer e com pare dwit hsoi l sample s take n fro mth e yard s o f home s wher e 3 7 case s o f lea dpoisonin g ha doccur red . Th e soi l lea dvalue s obtaine dha dawid e range , fro m1 t o 12,00 0 ppm , wit h7 5 percen t o f th e sam ple s containin g les s tha n 50 0 ppm . A significan t relationshi p betwee n soi l lea dlevel s an dlea d poisonin g case s wa s established ; 50 0 pp mwa s use d a s th e cutpoin t

i n th e chi-squar e contingenc y analysis . Thi s stud y wa s th e firs t t o examin e thi s comple x proble mand , althoug hdat asuppor t th e soi l lea dhypothesis , the y wer e no t suc ha s t o allo w fo r quantificatio n o f

th e relationshi p betwee n soi l lea dan dbloo dlea dlevels . Furthermore , becaus e n o othe r sourc e o f

lea dwa s measured , th e associatio n foun dmigh t

hav e bee n cause db y confoundin g addi

tiona l source s o f

lead , suc ha s pain t

o r air . 12-2 9P.3 9



### A late r study b y Galk e e t al. , als o i

n Charleston , usedahouse-to-hous e survey t o recrui t 194 blac k preschoo l children. 4 3 

### Soil lead , pain t lead , an dai r lea dexposure s a s measure db y traffi c densit

y wer e establishe dfo

r eac hchild . When th e populatio n was divide dint o 2 group s base don th e median soi l lead valu e (58 5 figlg), a5-Mg/d l differenc e i

n bloo dlead level s wa s obtained . Soil lea dexposure fo

r thi s populatio n range dfro

m9 t o 789 0 figlg. A multipl e regressio n analysi s o

f th e dat ashowedthat

vehicl e traffi c pattern , whe

n define db

y are ao f recruitmen t (i.e. , higho r

low) ; leadlevel i

n exterio r sidin g paint ; andleadi

n soi l wer e al l independentl y an dsignifi

cantl y relate dt o bloo dleadlevels . Barltro p e

t al. 10 0 

### describe dtw o studie s i n Englan d investigatin g th e soi l leadt o bloo dleadrelationship . In th e firs t

study , childre n aged2 an d3 an dthei r mother s fro

mtw o town s chosen fo

r thei r soi l lea d conten t eachhadthei r

bloo dleadlevel determine d fro macapillary sample . Hai r sample s wer

e als o col

lecte dan danalyze dfo

r lead . Leadconten t

o f th e suspende dparticulat e matte r andsoi l was measured . Soil sample s fo

r eachhome wer

e acomposite o

f several 2-in . cor e sample s take n fro mth e yar do

f eachhome . Chemical analysi s o f th e leadconten t

o f soil i n th e tw o town s showedatwo - t o threefol d difference , wit

hth e value s i

n th e contro l tow n being abou t 20 0 t o 30 0 pp

mcompare dwit

habou t 70 0 t o 1000 pp mi n th e expose dtown . A differenc e was als o note di n th e mea n ai r leadconten t

o f th e tw o towns , 0.6 9 Mg/m

3 

### compare dwit

h0.2 9 Mg/m

3



### . respectively . Althoug hthi s differenc e existed , bot hai r lea d value s wer

e though t low enoug hno t

t o affec t th e bloo dlevel value s differentially . Mea n surfac e soi l leadconcentration s fo

r th e tw o communitie s wer e statisticall y different , th e mean s fo r th e hig han dlow communit y bein g 90 9 and39 8 ppm , respectively . Despite thi s difference , n o statisticall y significant difference s in mothers ' bloo dlea dlevel s o r children' s bloo do r

hai r level s o f lea dwer e noted . Ther e was , however , suggestiv e evidenc e o f a differenc e i

n hai r leadlevel s fo

r children . Furthe r statistical analysi s o

f th e data , using correlationa l analysi s o n eithe r

ra w o r log-transforme dbloo dlead data , likewis e faile dt o show astatistical relationshi p o f soi l leadwit

heither bloo dleado r

hai r lead . Th e secon dstudy was reporte di n bot hpre liminar y an dfinal form. 10010 1 

### In th e more detaile d report, 10 1 

### children' s home s were classifie db y thei r soi l leadconten t

into thre e groups , namely < 1,000 , 1000 t o 10,000 , an d> 10,00 0 ppm . A s shown i n Ta

bl e 12-34 , children' s mea n bloo dleadlevel s in

crease dcorrespondingl y fro m20. 7 t o 29. 0 figldl. Mea n soi l leadlevel s fo

r th e low an dhighsoi l ex posure group s wer

e 42 0 an d13,96 9 ppm , respec tively . Mothers ' bloo dlevels , however , di dno t reflec t thi s trend ; no r

were th e children' s feca

l lead level s different

acros s th e soil exposure areas . TABL E 12-34 . MEA N BLOO D AN D SOI L LEA D CONCENTRATION S I N ENGLIS H STUDY 10 1 Categor y o f soi l lead , pp m <100 0 1000-1000 0 >1000 0 Sampl e siz e 2 9 4 3 1 0 Children' s

bloo d lead , n g/d l 20. 7 23. 8 29. 0 Soi l lea d

PP m 42 0 339 0 1396 9 

### Othe r studie s hav e investigate dth e relationshi p o f dus t leadt o absorption. 337810210 6 

### Som e o f thes e als o include dmeasurement s o f soi l lead . Lepo w e t al., 10 6 

### fo r example , studie dth e leadcon ten t o f air , housedust , an ddirt , a s well a s th e lea d conten t o f dir t on hands , food , an dwater , t o deter

mine th e caus e o

f chronicall y elevate dbloo dlead level s i n te n 2

- t o 6-year-ol dchildre n i n Hartford , Connecticut . Leadbase dpaint s hadbeen eliminate d a s asignificant

sourc e o

f lea dfo r thes e children . Ambient ai r leadconcentration s varie dfro m1. 7 t o 7. 0 Mg/m

3



### . Th e mea

n lea dconcentratio n i

n dir t was 1,20 0 figlg an di

n dust , 11,00 0 figlg. Th e mea n con centratio n o

f leadi n dir t on children' s hand s was 2,40 0 ppm . Th e mea

n weigh t o f sample s o

f dir t fro m hand s wa s 1 1 mg , whichrepresente donl y asmal l fractio n o f th e tota l dir t

on hands . Observatio n o f th e mouthin g behavio r

i n thes e youn g childre n lead t o th e conclusio n that

th e hands-in-mouthexposur e rout e wa s th e principa l caus e o f excessiv e lead accumulatio n i

n thes e children . Angl e e t al., 7 4 

### studyin g childre n i n Omaha , Nebraska , foundseveral interestin g association s be

tween soi l o r

housedus t

leadconcentration s an d bloo dleadlevels . In thi s report , thre e group s o f childre n wer

e compared : (1 ) suburban versu s urban hig hschool , (2 ) suburban versu s urban 10

- t o 12

- year-olds , an d(3 ) blac k

elementary schoo l childre n wit hbloo dlead< 2 0 versu s > 20 . Air leadlevels , al l o f whichwere les s than 1 Mg/m 3 

### , were no t

shown t o b e relate dt o bloo dleadlevels . Soil an dhousedus t wer e associated , althoug hno t alway s statisticall y significantly . Creaso n e t al., 10 2 

### studyin g hai r

metal level s i

n th e Ne w Yor k metropolitan area , use dbot hdustfal l an d housedus t

a s thei r

exposur e variables . Thre e geographi c area s i

n metropolita n Ne

w Yor k wer e chosen t o represen t

a n exposure gradient . Limite d dustfal l an dhousedus t

sample s wer

e take n t o verif

y 12-3 0th e gradien t an dt o estimat e it s magnitude . Hai r sample s wer e collecte dfro mresident s i n location s enrolle din othe r

ai r pollutio n studies . Mea n tota l environmenta l an dhai r lea dlevel s wer e the n com pared . Hai r

lea dlevel s range dfro m1 2 figlg in th e lo w are at o 1 7 figlg in th e high . Mea n dustfal l an d housedus t

lea dlevel s range dfro m2 t o 1 6 mg/m 2

- month , an dfro m27 9 t o 76 6 figlg. respectively . Hai r lea dlevel s in bot hchildre n an dadult s wer e foun dt o b e significantl y relate dt o bot hdustfal l an d housedus t

lead . N o attemp t

wa s mad e t o determin e th e origina l sourc e o f

thes e dusts . Further , th e stud y desig n di dno t

permi t th e establishmen t

o f whic ho f th e tw o dus t

type s o r bot hwer e th e actua l contribu

tor s t o th e hai r

lea dlevels . Th e investigator s con clude dtha t

th e primar y caus e o f

elevate dbloo dlea d level s in childre n wa s ingestio n o r inhalatio n o f

dus t containin g lead . Tw o othe r

studies , whic hwer e describe din mor e detai l in Sectio n 12.3 , ca n b e use dt o examin e th e relationshi p o f

lea din soi l an ddus t withlea di

n blood. 1

- 3 4 Yanke l e t

al . showe dtha t

lea din bot hsoi l an ddus t wa s independentl y relate dt o bloo dlea d levels . I n thei r

opinion , 100 0 pp msoi l lea dexposur e wa s caus e fo r

concern . Reanalysi s o f th e Dalla s traffi c stud y showe dasignifican t slop e o f bloo dlea d level s i n relatio n t o soi l lea dlevel s (/3 = 0.0662). 3 4 Lastly , Shellshear' s cas e repor t fro mNe w Zealan d ascribe s amedicall y diagnose dcas e o f lea dpoison

in g t o hig hsoi l lea dconten t i n th e child' s hom e environment. 10 7 Tw o studie s hav e investigate dth e mechanis mby whic hlea dfro msoi l an ddus t get s int o th e body. 10310 4 Sayr e e t

al . in Rochester , Ne w York , demonstrate dth e feasibilit y o f housedus t

bein g a sourc e o f lea dfo r children. 10 3 Tw o group s o f houses , on e inner-cit y an dth e othe r suburban , wer e chose n fo r th e study . Lead-fre e sanitar y pape r towel s wer e use dt o collec t

dus t sample s fro mhous e surface s an d th e hand s o f

children. 10 8 Th e median s fo r th e han d an dhousehol dsample s wer e use da s th e cutpoint s in th e chi-squar e contingenc y analysis . A statisticall y significan t

differenc e betwee n th e urba n an dsubur

ba n home s fo r

dus t level s wa s noted , a s wa s a relationshi p betwee n househol ddus t level s an dhan d dus t levels. 10 6 Te r Haa r an dAronow 10 4 investigate dlea d absorptio n in childre n tha t ca n b e attribute dt o in

gestio n o f

dus t an ddirt . The y reasone dtha t becaus e th e proportio n o f

th e naturall y occurrin g isotop e 210 P b varie s fo r

pain t chips , airborn e particulates , fallou t dust , housedust , yar ddirt , an dstree t dirt , it woul db e possibl e t o identif y th e source s o f

ingeste d lead . The y collecte d24-h r excret afro m8 hos

pitalize dchildre n fo r

th e firs t da y o f hospitalization . Thes e children , 1 t o 3 year s old , wer e suspecte do f havin g elevate dbod y burden s o f lead , an don e cri

terio n fo r

th e suspicio n wa s ahistor y o f pica . Te n childre n o f

th e sam e ag e level , wh o live din goo d housin g in Detroi t

an dth e suburbs , wer e selecte da s control s an d24-h r

excret awer e collecte dfo r them . Th e excret awer e drie dan dstabl e lea da s wel l a s 210 P b conten t

wa s determined . Fo r seve n hospi

talize dchildren , th e stabl e lea dmea n valu e wa s 22.4 3 figlg dr y excreta , an dth e eight hchil dha da valu e o f 164 0 figlg. Th e controls ' mea n fo r stabl e lea dwa s 4. 1 figlg dr y excreta . However , th e respec tiv e mean s fo r

210 P b expresse da s pCi/ g dr y matte r wer e 0.04 4 an d0.040 . Th e author s conclude dtha t becaus e ther e i s n o significan t differenc e betwee n thes e mean s fo r 210 Pb , th e hypothesi s tha t youn g childre n withpic aea t dus t i s no t supported . However , al l tha t

th e data , in fact , d o sho w i s tha t bot hgroup s o f

childre n wer e comparabl e a s t o th e amount s o f

210 P b an dvastl y differen t i n respec t

t o stabl e lea dpe r

gra mo f dr y excreta . Th e hospitalize d childre n ingeste dlarge r amount s o f

materia l con tainin g stabl e lead . Grantin g tha t th e hospitalize d childre n ingeste dleade dpain t chip s an dth e control s di dnot . doe s no t

permi t th e conclusio n tha t

al l th e 210 P b foun din al l th e childre n originate din foo d an dtha t n o dir t an ddus t

wa s ingeste db y contro l childre n wherea s hospitalize dchildre n at e onl y pain t chips . Th e dat afro mal l thes e studie s ca n b e summarize d fairl y succinctly . Ther e i s evidenc e tha t childre n ca n pick u p lea dfro mthei r

environmen t

b y gettin g i

t o n thei r hands . Dugga n an dWilliams 10 5 hav e sum marize dth e literatur e o n th e amount s o f lea din

geste db y ingestio n o f

dust . I n thei r

opinion , aquan tit y o f 5 0 M g o f lea di s ingeste ddail y b y childre n b y mean s o f stree t dust . A s yet

ther e ar e n o soli ddat a directl y demonstratin g th e nex t link , tha t

is , transfe r o f dus t an dsoi l fro mhan dt o mouth . A clinica l cas e repor t ha s indicated , however , tha t soi l lea dlevel s ca n lea dt o excessivel y elevate dbloo dlea dlevels . Also , th e dat ao f

Barltrop 10 1 an dGalk e e t al. 4 3 indi

cat e tha t soi l lea dexposures , ofte n foun din urba n settings , ca n contribut e betwee n 5 an d8 figldl t o th e blood' s lea dburden. 3310 1 Th e consensu s appear s t o b e tha t observabl e in- , crease s in bloo dlea dlevel s occu r a t soi l o r dus t lea d exposure s o f

50 0 t o 100 0 ppm . Fro mth e dat aavail

abl e in th e literature , asummar y tabl e (Tabl e 12-35 ) wa s constructe db y EPA . A regressio n analysi s wa s use dt o relat e th e logarith mo f th e 12-3 1P.4 1



### bloo dleadt o th e logarith mo f th e soil lead . Fro m th e regression , acoefficient , b , th e mea n percen t ag e increas e i n bloo dlea

dfo r atw o fol dincreas e i

n soil TABLE 12-35 . SUMMAR

Y O F SOI L LEAD/BLOO D LEAD RELATIONSHIP S 

### lead , ca n b e calculated : % increas e = 10

0 [exp(b/lo g (2)) ] (12-7 )

Stud y Age , years Regressio n coefficient , log-lo g Geom . mea n bloo d lead , ug/d l Geom . mea n soi l level . »g/ g Mea n % increas e

i n Pb- B fo r 2 x soi l leve l Charleston.SC 4 3 Kellogg , ID 1 Dallas , TX 3 4 England 10 1 1- 5 1- 9 1- 5 2-3 0.043 2

0.052 8 0.066 2 0.084 0 36. 4 37. 5 11. 4 23. 2 451. 6

1518. 1 91. 6 1849. 1 3. 0

3. 7 4. 7 6. 0 

### Tabl e 12-3 5 show s asurprisin g consistenc y i n th e percentag e increas e i

n mea n bloo dleadlevel s for

a twofol dincreas e i

n soi l leadlevel s ( 3 t o 6 percent) , given th e wid e diversity i n population s studie dand soi l level s encountered . Th e Charlesto n study in

volve dblac k

preschoo l childre n livin g i n th e inner cit y wit hseveral additiona l known environmenta l source s of lead . Th e Idah o study was o f asmelter site i n arura l setting . Barltrop' s dat afro mEnglan d showe dvirtuall y n o environmenta l sourc e othe r than that fro msoil . Th e Dalla s study was o f acom munit y tha t wa s relativel y leadfree . It i s interestin g t o note tha t

th e large r

estimate s o

f th e percentag e in

creas e i n bloo dleadoccurre di

n th e childre n wit

h th e lowes t bloo dlea

dlevels . 12.3. 3 Food an

d Wate rExposure s In typical urban settings , foodprobabl y con stitute s th e body' s larges t direc t sourc e o

f lea d becaus e almos t

ever y ite mi n th e die t contain s som

e measurabl e amoun t

o f th e metal . Thre e approache s hav e been usedt o estimat e die

tary intake o

f lead : duplicat e meals , marke t baske t surveys , an dfeca

l leaddeterminations. Th e esti

mate ddietar y lea dintak e of American s ha s decrease dmarkedl y sinc e th e presentatio n of Kehoe' s dat ai

n th e 1940's , whichindicated , base d o n feca l leaddeterminations , that th e dail y intake was between 100 an d35 0 fig/day. 88 

### Mos t o f th e more recen t

comparabl e data 210911 0 

### hav e reduce d that estimate t o between 5 0 an d15 0 Mg/day . Th e Californi astudy o

f Johnso n e

t al. 7 

### point s t o adail y intake o f abou t 10 0 t o 15 0 Mg . suc

hintake bein g simila r for bot hrura l an durban populations . Also , Chishol man dHarrison, 10 9 

### i n astudy o

f childre n aged1 2 t o 3 5 months , foundamea n feca l excretio n rat e o f 13 2 Mg/day , an dBarltro p an dKillol aavalu e o f 130Mg- 11 0 

### Muchrecen t

wor k ha s been concerne dwit hth e leadconten t

o f th e marke t

baske t o r tota l die t

i n whichth e conten t

o f food s meetin g typical nutri

tiona l need s i s analyzed . Th e foodstuff s ar e assem ble di n accordanc e wit

hnationa l foo dsampl e sur veys . On e suchstudy 11111 2 

### ha s indicate dthat th e leadconten t

o f th e die t o f youn g adult s average s 15 0 t o 20 0 Mg/day , andanother 11 3 

### cite s afigur e o f 25 4 Mg/da y fo r 15

- t o 20-year-ol dmales . A t leas t 3 0 per cent o f thi s amoun t

i n th e latte r

study was attribute d t o th e consumptio n o

f canne dfoods . Kolbye 11 1 

### an d Mahaffe y et al. 11 2 

### hav e suggeste da

n averag e food

base dintake o

f 8 0 t o 100 M

g o f leadfo r childre n 1 2 t o 3 5 month s old . Additiona l studie s i n thi s field hav e been reviewe db

y Mahaffey. 11 2 

### Despite th e abov e estimate s o f dietary leadcon tent , th e quantitativ e relationshi p between dietary intake an dbloo dlea

dlevel s i s no t

well established ; th e bulk o f th e studie s describe di

n Chapte r 1 0 that addres s thi s relationship , however , poin t t o asus taine dvalu e o

f 6 figldl fo r 10 0 M g o f dietary leadin

take . Water , itself

, ca n als o b e asourc e o

f significant quantitie s o

f leadwit hth e metal presen t

i n th e sup ply itself . Mor e frequent , however , i s a n increas e i

n th e quantity o

f particulat e or

dissolve dleada s water i s delivere dfro

mth e treatmen t

plan t t o th e use

r throug hth e leadpipe s ofte n foundi n olde r housing . Mos t natura l water s contai n onl y fro m1 0 t o 2 0 Mg/lite r o f leadan dmos t

problem s occur

whe n lead pipin g i s use di

n area s i n whichth e drinkin g water i s lea dsolvent ; tha t

is , i t i s sof t an dha s alow pH . Althoug hth e us e o

f lea dpipin g ha s been largel y prohibite din recen t

construction , occasiona l episode s o

f poisonin g fro

mthi s leadsourc e stil l oc cur . Thes e case s mos t

frequentl y involv e isolate d farm s o r house s i n rura l areas , but

asurprisin g situa

tio n was reveale di

n 197 2 whe

n Beatti e et

al. 114



### - 11 5 

### showedth e seriousnes s o

f th e situatio n i

n Glasgow , Scotland , whichha

dver y pur e bu t

sof t drinkin g water a s it s source . They demonstrate daclear asso ciatio n between bloo dlea dlevel s an dinhibitio n o

f th e enzyme ALA D i

n childre n livin g i

n house s wit

h (1 ) leadwater

pipe s an dleadwater

tanks , (2 ) n o 12-3 2lea dwate r tan k bu t withmor e tha n 6 0 f

t o f lea dpip

ing , an d(3 ) les s tha n 6 0 f t o f lea dpiping . Th e mea n lea dconten t

o f th e wate r

a s supplie db y th e reservoi r wa s 17. 9 figlliler; tha t take n fro mth e faucet s o f group s 1 , 2 , an d3 wa s 934 , 239 , an d10 8 Mg/l'ter , respectively . Anothe r Englis hstudy 1 1 6 showe daclea r differenc e betwee n th e bon e lea dconten t o f th e population s o f

Glasgo w an dLondon , th e latte r hav

in g ahard , relativel y nonsolven t wate r supply.

- I n astud y o f

120 0 bloo ddonor s in Belgium, 11 7 person s fro mhome s withlea dpipin g an dsupplie d withcorrosiv e wate r

ha dsignificantl y highe r bloo d lea dlevels . I n Boston , Mass. , an investigatio n wa s mad e o f wate r distribute dvi alea dpipes . I n additio n t o th e dat ao n lea di n water , accoun t wa s take n o f socioeconomi c an ddemographi c factor s a s wel l a s othe r source s o f

lea din th e environment. 11811 9 Par

ticipants , 77 1 person s fro m38 3 households , wer e classifie dint o ag e group s o f <6 , 6 t o 20 , an d>2 0 year s o f ag e fo r analysis. 11 8 A clea r

associatio n be

twee n wate r

lea dan dbloo dlea dwa s apparen t (Ta

bl e 12-36) . Fo r

childre n unde r

6 year s o f

age , 34. 6 percen t o f thos e consumin g wate r withlea dabov e th e U.S . standar do f

5 0 Mg/'i te r

ha dabloo dlea d valu e 2 3 5 figldl. wherea s onl y 17. 4 percen t o f thos e consumin g wate r

withi n th e standar dha dbloo dlea d valuesof23 5 figldl. TABL E 12-36 . BLOO D LEA D LEVEL S O F 77 1 PERSON S I N RELATIO N T O LEA D CONTEN TO F DRINKIN G WATER ,

BOSTON , MASS. 11 8 Person s consumin g wate r(standin g gra b samples ) Bloo d lea d levels , /jg/d l <50ii g Pb/lile r f5G>gPb/lite r No . Percen t Percen t Tota l <3 5 >3 5 Tota l 62 2

6 1 68 3 9 1

9 10 0 6 8

2 0 8 8 77. 3

22. 7 100. 0 69 0

8 1 77 1

x = 14.35 ; d l = 1 . P <0.01 . Greathous e e t

al . hav e publishe da n extensiv e regressio n analysi s o f

thes e data. 11 9 Bloo dlea d level s wer e foun dt o b e significantl y relate dt o age , educatio n o f

hea do f household , sex , an dwate r lea d exposure . O f

th e tw o type s o f

wate r sample s taken , standin g gra b an drunnin g grab , th e forme r wa s show n t o b e mor e closel y relate dt o bloo dlea d level s tha n th e latter . A s note din Chapte r

1 0 o f thi s document , roughl y 1 0 percen t

o f lea di n soli dfoodstuffs i s absorbe db y adults ; th e correspondin g valu e fo r liquid s i s abou t 5 0 percent . Th e relativ e ris k fo r exposur e t o water born e lea dis , therefore , considerabl y greater . 12.3. 4 Effect s o f Lea d i n th e Housin g Environ ment : Lea d i n Pain t A majo r sourc e o f

environmenta l lea dexposur e fo r th e genera l populatio n come s fro mlea dcon taine di n bot hinterio r

an dexterio r

pain t o n dwell

ings . Th e amoun t

o f lea dpresent , a s wel l a s it s ac cessibility , depend s upo n th e ag e o f th e residenc e (becaus e olde r

building s ar e painte dwithpain t manufacture dbefor e lea dconten t wa s regulated ) an dth e physica l conditio n o f th e paint . I t

i s generall y accepte db y th e publi c an db y healt hpro fessional s tha t

lea dbase dpain t

i s th e majo r

sourc e o f pediatri c lea dpoisonin g withclinica l symptom s in th e Unite dStates. 12 0 Th e leve l an ddistributio n o f lea dpain t

in adwell

in g i s acomple x functio n o f history , geography , eco nomics , an dth e decoratin g habit s o f it s residents . Lea dpigment s wer e th e firs t pigment s produce do n a larg e commercia l scal e whe n th e pain t industr y bega n it s growt hin th e earl y 1900's . I n th e 1930' s lea dpigment s wer e graduall y replace dwithzin c an d othe r opacifiers . B y th e 1940's , titaniu mdioxid e becam e availabl e an dha s no w becom e th e mos t commonl y use dpigmen t fo r residentia l coatings . Ther e wa s n o regulatio n o f th e us e o f

lea di n hous e paint s unti l 1955 , whe n th e pain t industr y adopte da voluntar y standar dtha t limite dth e lea dconten t in paint , fo r interio r uses , t o n o mor e tha n 1 percen t b y weigh t o f th e nonvolatil e solids . A t abou t th e sam e time , loca l jurisdiction s bega n adoptin g code s an d regulation s tha t

prohibite dth e sal e an dus e o f in

terio r paint s containin g mor e tha n 1 percen t lead. 12 1 I n spit e o f

th e chang e i n pain t

technolog y an d loca l regulation s governin g it s use , an dcontrar y t o popula r belief , interio r

pain t wit h significan t amount s o f

lea dwa s stil l availabl e i n th e 1970's . A 197 1 stud y in Ne w Yor k Cit y foun dtha t

8 o f 7 6 paint s teste dha dalea dconten t rangin g fro m2. 6 t o 10. 8 percent , wel l abov e th e city' s legall y permissi

bl e 1 percen t

level. 12 2 Late r

studie s b y th e Nationa l Burea u o f

Standards 12 3 an db y th e Consume r Pro

duc t Safety Commission 12 4 showe dacontinuin g decreas e i n th e numbe r o f interio r paint s wit hlea d level s greate r

tha n 1 percent . B y 1974 , onl y 2 per cen t o f th e interio r

paint s sample dwer e foun dt o hav e greate r

tha n 1 percen t

lea din th e drie dfilm. 12 4 Th e leve l o f

lea di n pain t

in aresidenc e tha t shoul db e considere dahazar dremain s i n doubt . No t onl y i s th e tota l amoun t o f lea di n pain t

important , bu t als o th e accessibilit y b y achil do f th e painte d 12-3 3P.4 3

surfac e a s wel l a s th e frequenc y o f ingestion . At

tempt s t o se t

a n acceptabl e lea dlevel , in situ, hav e bee n unsuccessfu l an dpreventiv e contro l o f lea d pain t hazard s ha s bee n concerne dwit hlevel s o f lea d in pain t currentl y manufactured . I n on e o f it s reviews , NA S concluded : '"Sinc e contro l o f th e lea d pain t hazar di s difficul t

t o accomplis honc e multipl e layer s hav e bee n applie din home s ove r tw o t o thre e decades , an dsinc e contro l i s mor e easil y regulate d at th e tim e o f

manufacture , w e recommen dtha t th e lea dconten t

o f paint s b e se t

an denforce dat

tim e o f manufacture." 12 5 Lega l contro l o f

lea dpain t

hazard s i s bein g at tempte db y loca l communitie s throug hhealt ho r housin g code s an dregulations . A t th e Federa l level , th e Departmen t

o f Housin g an dUrba n Develop

men t ha s issue dregulation s fo r lea dhazar dabate

men t in housin g unit s assiste do r supporte db y it s programs . Generally , th e lea dleve l considere d hazardou s range s fro m0. 5 t o 2. 5 mg/cm 2 , bu t th e leve l o f lea dconten t

selecte dappear s t o b e depen

den t mor e o n th e sensitivit y o f fiel dmeasuremen t

b y differen t regulator y bodie s (usin g X-ra y fluorescen t lea ddetectors ) tha n o n direc t biologica l dose

respons e relationships . Regulation s als o requir e lea dhazar dabatemen t

whe n th e pain t

i s loose , flak

ing , peeling , o r

broken , o r

i n som e case s whe n it

i s o n surface s withi n reac ho f achild' s mouth . Som e studie s hav e bee n carrie dou t t o determin e th e distributio n o f

lea dlevel s in pain t

in residences . A surve y o f

lea dlevel s in 237 0 randoml y selecte d dwelling s i n Pittsburg hprovide s som e indicatio n o f th e lea dlevel s t o b e found. 12 6 Figur e 12- 9 show s th e distributio n curve s fo r

th e highes t

lea dleve l foun d in dwelling s fo r

thre e ag e groupings . Th e curve s bea r ou t th e statemen t

ofte n mad e tha t

pain t withhig h level s o f lea di s mos t

frequentl y foun di

n pr e 194 0 residences . On e canno t assume , however , tha t hig h leve l lea dpain t

i s absen t

i n dwelling s buil t

afte r 1940 . I n th e cas e o f

th e house s surveye din Pitts

burgh , abou t

2 0 percen t

o f th e residence s buil t

afte r 196 0 hav e at

leas t on e surfac e withmor e tha n 1. 5 mg/cm 2 lead . Th e distributio n o f

lea dwithi n a n individua l dwellin g varie s considerably . Figur e 12-1 0 present s th e distributio n o f

th e highes t

pain t lea dmeasure ment s o n walls , doors , an dwindow s fo r al l th e building s sampled . Thes e dat asho w tha t th e lea di s no t uniforml y distribute dthroughou t th e units . Lea d pain t i s mos t frequentl y foun do n door s an dwin

dow s wher e lea dlevel s greate r tha n 1. 5 mg/cm 2 wer e foun do n 2 percen t

o f th e surface s surveyed , wherea s A l

LEA D LEVE L (X) . mg/c m Figur e 12-9 . Cumulativ e distributio n o f lea d level s i n dwellin g units:* " onl y abou t

l percen t

o f th e wall s ha dlea dlevel s greate r tha n 1. 5 mg/cm 2

. 12 6 Th e literature 12 0 generall y accept s th e premis e tha t th e presenc e o f

lea din pain t

i s anecessar y bu t no t sufficien t

conditio n fo r

ahazar dt o b e present . Accessibilit y in term s o f peeling , flaking , o r

loos e pain t i s als o anecessar y conditio n fo r th e presenc e o f ahazard . Figur e 12-1 1 show s th e distributio n o f lea dlevel s an dnonintac t condition s fo r

dwelling s an dsurface s fo r

th e Pittsburg hsample . O f th e tota l sample s surveyed , abou t 1 4 percen t

o f th e residence s woul dhav e accessibl e pain t wit halea dconten t greate r tha n 1. 5 mg/cm 2

. I t i s no t possibl e t o extrapolat e th e result s o f th e Pittsburg hsurve y nationally ; however , additiona l dat afro mapilo t

stud y o f 11 5 residence s i n Wash

ington . D.C . showe dsimila r results. 12 7 A n attemp t

wa s mad e i

n th e Pittsburg hstud y t o obtai n informatio n abou t th e correlatio n betwee n 12-3 4A l 

### 1

0 

# r—i—, — 0. 9

0. 8

0. 7

0. 6

0. 5

0. 4

0. 3

0. 2

0. 1 1 

### 1 i 1' . 

## y, \\\ 

## I M M

" * \ 

## 1 M 1 M " 1 \ \ 1 * K 1 M - 1 \ \ I VjW-DOOR S 

### r - \ A \ U 

## \ n \ \

" i 

### i i i



## I i """?" " -

_

-

-

LEA D LEVE L (X) , mg/c m Figur e 12-10 . Cumulativ e distributio n o l lea d level s b y loca tio n i n dwelling , al l ages. 12 6 th e quantit y an dconditio n o f lea dpain t

i n building s an dth e bloo dlea do f

childre n wh o reside dthere. 12 8 Bloo dlea danalyse s an dsocioeconomi c dat afo r 45 6 childre n wer e obtaine dalon g withth e informatio n abou t lea dlevel s in th e dwelling . Figur e 12-1 2 shows-th e cumulativ e distributio n o f th e bloo dlea d level s fo r thi s group . Figur e 12-1 3 i s aplo t o f th e bloo dlea dlevel s versu s th e fractio n o f surface s withi n adwellin g wit hlea dlevel s o f a t leas t 2 mg/cm 2

. Analysi s o f

th e dat ashow s alo w correlatio n betwee n th e bloo dlea dlevel s o f th e childre n an d fractio n o f

surface s withlea dlevel s abov e 2 mg/cm 2 , bu t astronge r

correlatio n betwee n th e bloo dlea d level s an dconditio n o f th e painte dsurface s in th e dwellin g i n whic hchildre n reside . Thi s latte r cor relatio n appeare dt o b e independen t o f th e lea d level s i n th e dwellings . Tw o othe r

studie s hav e attempte dt o relat e bloo d lea dlevel s an dpain t

lea da s determine db y X-ra y fluorescence . Reec e e t

al . in Cincinnat i studie d8 1 LEA D LEVE L (XI . mg/cm * Figur e 12-11 . Cumulativ e distributio n o f lea d level s i n dwell in g unit s wit h unsoun d pain t conditions. 12 6 childre n fro mtw o lowe r socioeconomi c com munities. 12 9 Bloo dlead s wer e analyze db y th e dithizon e method . Ther e wa s considerabl e lea di n th e hom e environment , bu t i t wa s no t reflecte di n th e children' s bloo dlead . Analyti c procedure s use dt o tes t th e hypothesi s wer e no t described ; neithe r

wer e th e ra w dat apresented . Galk e e t al . in thei r

stud y o f

inner-cit y blac k childre n measure dth e pain t lead , bot hinterio r

an d exterior , a s wel l a s soi l an dtraffi c exposure. 4 3 I n a multipl e regressio n analysis , exterio r sidin g pain t lea dwa s foun dt o b e significantl y relate dt o bloo d lea dlevels . Althoug hmos t

o f th e evidenc e indicate s tha t th e sourc e o f exposur e i n childhoo dlea dpoisonin g i s almos t invariabl y peelin g lea dpain t an dbroke n lead-impregnate dplaste r foun di n poorl y main

12-3 5P.4 5

5 io o 5 8 0 "TT " ~n —r—i—i i i i i i i—i—i— i i i i i i - |

STD . DEV. = 1.3 9 MEDIA N =20.7wg/d l

\ III I IIIII1 IIIII Figur e 12-12 . Cumulativ e frequenc y distributio n o f bloo d lea d level s foun d i n Pittsburg h housin g survey. 12 6 

### Th e finding s ar e presente di n orde r t o plac e i

n prope r perspectiv e bot

hth e concep t

o f tota l leadex posure an dth e concep t

that lea dpain t i s on e sourc e o f leadtha t contribute s t o th e tota l bod y load . Th e backgroun dcontributio n o f leadfro mothe r source s i s stil l no t known eve

n fo r thos e childre n fo

r who ma potential lead-pain t

hazar dha s been identified ; nor i s i t known wha

t proportio n o

f leadcame fromwhich source . TABL E 12-37 . RESULT S O F SCREENIN G AN D HOUSIN G INSPECTIO N I N CHILDHOO D LEA D POISONIN G CONTRO L

PROJEC T B Y FISCA L YEAR" 1 . 1 "

z > U J LJ J

Q 2 0 O o I I I I I I I I

SURFACE S I N BA D CONDITION , i.e. , PEELIN G

_CHALKING , O R POO R SUBSTRAT E

AL L SURFACE S * •

I I I I •

' I I I o I I

-

—— •—

I Fisca l year 8

Result s 1976' " 197513 ' 1974" '

0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9 1. 0

FRACTION S O F SURFACE S WIT H LEA D > 2 mg/cm 2 Figure 12-13 . Correlatio n of children' s bloo d lea d level s wit h fraction s of surface s withi n a dwellin g havin g lea d concentra tion s 2 2 m g Pb/cm 2 . 

### taine dhouses , ther e ar e als o report s o f exposure case s that canno t b e equate dwit

hth e presenc e o

f leadpaint . Further , th e analysi s o f pain t i n home s o f childre n wit

hleadpoisonin g ha s no t consistentl y reveale dahazardou s leadcontent. 12 0 

### Fo r example , on e paper reporte d546 6 sample s o f pain t obtaine d fro mth e home environmen t o f leadpoisonin g case s i n Philadelphi abetween 196 4 an d1968 . Amon g thes e 546 6 sample s o

f paint , 6 7 percen t

yielde dposi

tiv e finding s define da s pain t wit hmore than 1 per cent lead. 13 0 

### Dat apublishe do r

mad e availabl e b

y th e Center fo r Diseas e Control , Departmen t o f Health , Educa

tion , an dWelfare , als o show that asignificant

num be r o f childre n wit

hundu e lea

dabsorptio n occup y building s that

wer e inspecte dfo

r lead-base dpaint hazards , bu t

i n whichno hazar dcoul db e demon

strated. 13113 2 

### Tabl e 12-3 7 summarize s th e dat aob

taine dfro

mth e HE

Wfundedlead-base dpaint poisonin g contro l project s fo r fisca l year s 1974 , 1975 , an d1976 , plu s th e transitio n quarte r Jul y 1 , 197 6 t o September

30 , 1976 . Thes e dat ashow that i n abou t 4 0 t o 4 5 percen t

o f confirme dcase s o

f ele

vate dbloo dleadlevels , apossibl e sourc e o f lea d pain t hazar dcoul dno t

b e located . Th e implication s o f thes e finding s ar e no t

clear . They shoul dnot , however , weaken th e rol e o f lead-base dpain t

a s a major environmenta l sourc e o f leadfo r children . No . childre n

screene d No . childre n wit h elevate d lea d exposur e No . dwelling s inspecte d No . dwelling s wit h lea d hazar d 500,46 3 440,65 0 371,95 5 69,131 " 28,5971 = 16,228< = 50,27 6 30,22 7 23,09 6 28,33 3 17,60 9 13,74 2

a Fisca l yea r197 6 include s transitio n quarter . b CD C Classe s ll-IV . 0 Confirme d bloo d lea d leve l if"4 0 ug/dl . 

### 12.3. 5 Secondary Exposur e o f Childre n from Parents ' Occupationa

l Exposure Excessiv e intake an dabsorptio n o f leadfo r childre n ca

n resul t whe n aparen t

who work s i

n a dust y environmen t

wit hahig hleadconten t

bring s dus t home on hi s clothes , shoes , o r even hi s automo bile . Onc e home , thi s dus t i s the n availabl e t o hi s children . Excessiv e intake andabsorptio n als o ca n occur whe n childre n voluntaril y inges t nonfoo ditems , suc ha s clay , plaster , or

pain t chips . Thi s i s th e classi

ca l pica , whichrefer s t o th e intentional ingestio n o f nonfoo dmateria l rathe r

than t o th e passive , nonin

tentiona l ingestio n o

f dus t fro madirty finge

r o r piec e o f candy that

ha s been droppe dan dthu s con taiminated . Landrigan e

t al. 6 2 

### reporte dthat

th e 174 childre n o f smelter worker s who live dwithi n 2 4 k mo f th e smelter hadsignificantly higher

bloo dleadlevels , a mea n o f 55. 1 figldl, than th e 51 1 childre n o f person s i n othe r occupation s wh

o live di n th e same area s whos e mea

n bloo dleadlevel was 43. 7 figldl. Analyse s b

y EP A staf f o f th e dat acollecte di

n Idah o showe dthat

employment

o f th e father

a t th e lea dsmelter , a

t azin c smelter , o r

i n th e leadmin e 12-3 6resulte din highe r bloo dlea dlevel s in th e childre n livin g in th e sam e hous e withsuc hfather s tha n childre n whos e father s wer e employe din differen t location s (Tabl e 12-38) . TABL E 12-38 . GEOMETRI C MEA N BLOO D LEA D LEVEL S (Mg/dl ) O F CHILDRE N BY PARENTA L EMPLOYMEN T

(EP A analysi s o

f 1974 data ) Ag e an d stud y are a 1 t o 3 year s 1 2 3 4 5 6 4 t o 9 year s 1 2 3 4 5 6 Lea d smelte r

worke r 77.1(12)= * 56.8(11 ) 33.7(6 ) 29.6(4 ) — — 73.6(32 ) 49.6(21 ) 33.3(21 ) 30.9(4 ) 24.5(2 ) — Lead/zin c

min e worke r 65.7(25 ) 53.5(21 ) 54.5(15 ) 36.0(16 ) 31.8(29 ) — 65.8(28 ) 43.8(32 ) 35.5(39 ) 33.0(53 ) 27.1(79 ) — Zin csmelte r

worke r 66.3(11 ) 55.1(6 ) 32.3(2 ) 41.7(4 ) — — 59.3(16 ) 51.9(4 ) 35.2(7 ) 35.6(5 ) — — Othe r

occupatio n 65.9(13 ) 48.5(30 ) 34.8(26 ) 31.5(22 ) 27.2(16 ) 22.4(34 ) 59.2(33 ) 44.9(67 ) 32.1(58 ) 29.1(44 ) 26.4(60 ) 20.5(56 )

a Sampl e size s i n parentheses . Th e effec t

associate dwit hparenta l employmen t appear s t o b e muc hmor e prominen t in th e mos t

con taminate dstud y area s neares t t o th e smelter . Thi s ma y b e th e effec t

o f a n intervenin g socioeconomi c variable : th e lowes t

pai dworkers , employe di n th e highes t exposur e area s withi n th e industry , migh t b e expecte dt o liv e i n th e mos t undesirabl e locations , whic har e closes t

t o th e smelter . Th e importanc e o f

th e infiltratio n b y lea ddust s int o clothing , particularl y th e undergarments , o f lea dworker s ha s bee n demonstrate di n anumbe r o f studie s o f

th e effect s o f

smelters. 13 3 I t

wa s note di n th e Unite dKingdo mtha t elevate dbloo dlea dlevel s wer e foun di n th e wive s an dchildre n o f worker s eve n whe n the y reside dsom e considerabl e distanc e

fro mth e facility . I t

wa s mos t

prominen t

i n th e familie s o f

worker s wh o themselve s ha delevate d bloo dlea dlevels . Quantitie s o f lea ddus t wer e foun d in workers ' car s an dhomes . I t apparentl y i s no t sufficien t fo r afactor y merel y t o provid e oute r pro tectiv e clothin g an dshowe r facilitie s fo r

lea d workers . I n anothe r

stud y in Bristol , fro m65 0 t o 140 0 pp mo f

lea dwa s foun di n th e undergarment s o f worker s a s compare dwit h3 t o 1 3 pp mi n undergar

ment s o f contro l subjects . Lea ddus t wil l remai n o n th e clothin g eve n afte r

laundering : u p t o 50 0 m g o f lea dha s bee n foun dt o remai n o n a n overal l garmen t afte r washing. 13 4 Bake r e t al. 13 5 foun dbloo dlea dlevel s >3 0 figldl i n 3 8 o f 9 1 childre n whos e father s wer e employe da t asecondar y lea dsmelte r in Memphis , Tenn . House

dust , th e onl y sourc e o f lea di n th e home s o f

thes e children , containe damea n o f 268 7 figlg compare d with40 4 figlg i n th e home s o f agrou p o f

matche d controls . Mea n bloo dlea dlevel s in th e workers ' childre n wer e significantl y highe r tha n thos e fo r control s an dwer e closel y correlate dwit hth e lea d conten t o f househol ddust . I n home s wit hlea di n dus t < 100 0 figlg, 1 8 childre n ha damea n bloo d lea dleve l o f

21. 8 ± 7. 8 figldl, wherea s i n home s wher e lea din dus t

wa s >700 0 figlg, 6 childre n ha d amea n bloo dlea dleve l o f 78. 3 ± 34. 0 figldl. Landriga n e t

al. 6 2 als o reporte dapositiv e histor y o f pic afo r 19 2 o f th e 91 9 childre n studie di n Idaho . Thi s histor y wa s obtaine db y physicia n an dnurs e in

terview s o f

parents . Pic awa s mos t commo n amon g 2-year-ol dchildre n an donl y 1 3 percen t o f thos e withpic awer e abov e ag e 6 . Highe r bloo dlea dlevel s wer e observe di n childre n wit hpic atha n i n thos e withou t pica . Tabl e 12-3 9 show s th e mea n bloo d lea dlevel s i n childre n a s the y wer e affecte db y pica , occupatio n o f

th e father , an ddistanc e o f residenc e fro mth e smelter . I t

i s interestin g that , amon g th e TABL E 12-39 . GEOMETRI C MEA N BLOO D LEA D LEVEL S FO R CHILDRE N BASE D O N REPORTE D OCCUPATIO N O F FATHER , HISTOR Y O F PICA , AN D DISTANC E O F RESIDENC E FRO M SMELTER "

Are a 1 2 3 4 5 6 Distanc e Iro m smeller , k m 1. 6 1. 6 t o 4. 0 4. 0 t o 10. 0 10. 0 t o 24. 0 24. 0 t o 32. 0 75 . Pic a

78. 7 50. 2 33. 5 — — — Lea d smelte r worke r N o

pic a 74. 2 52. 2 33. 3 30. 3 24. 5 — Lead/zin cmin e

Pic a 75. 3 57. 1 36. 7 38. 0 31. 8 — worke r N o

pic a 63. 9 46. 9 33. 5 32. 5 27. 4 — Zin csmelte r

Pic a 69. 7 62. 7 36. 0 40. 9 — — worke r N o

pic a 59. 1 50. 3 39. 6 36. 9 — — Othe r

occupation s N o Pic a pic a 70. 8 59. 9 37. 2 46. 3 33. 3 32. 6

—39. 4 28. 0 26. 4 17. 3 21. 4 12-3 7P.4 7

population s livin g neares t t o th e smelter , environ

menta l exposur e appear s t o b e sufficien t a t time s t o mor e tha n overshado w th e effect s o f pica , bu t

thi s findin g ma y als o b e cause db y inadequacie s inheren t i n collectin g dat ao n pica . Thes e dat aindicat e tha t in aheavil y contaminate d area , bloo dlea dlevel s in childre n ma y b e signifi

cantl y increase db y th e intentiona l ingestio n o f non foo dmaterial s havin g ahig hlea dcontent . Dat ao n th e parents ' occupation s are , however , mor e reliable . I t

mus t b e remembere dals o tha t th e stud y area s wer e no t homogeneou s socioeconomically . I n addition , th e typ e o f wor k an individua l doe s in an industr y i s probabl y muc h mor e importan t

tha n simpl y bein g employe din a particula r

industry . Th e presenc e i n th e hom e o f

an industria l employe e expose doccupationall y t o lea d may produc e increase s in th e bloo dlea dlevel s rang in g fro m1 0 t o 3 0 percent . 12.3. 6 Miscellaneou s Source s o f Lea d Althoug hn o studie s ar e available , it i s conceiva

bl e tha t destructio n o f

lead-containin g plastic s (t o recove r copper) , whic hha s cause dcattl e poisoning , als o coul dbecom e asourc e o f lea dfo r humans . A mor e genera l proble mi s wast e disposal , becaus e lead-containin g material s ma y b e incinerate dan d may thu s contribut e t o increase dai r lea dlevels . Thi s sourc e o f lea dha s no t

bee n studie din detail . Th e consumptio n o f

illicitl y distille dliquo r ha s bee n show n t o produc e clinica l case s o f lea dpoison

ing . Domesti c an dimporte dearthenwar e wit him

properl y fire dglaze s hav e als o bee n relate dt o clini

ca l lea dpoisoning . Thi s sourc e become s importan t whe n food s o r

beverage s hig hin aci dar e store di n container s mad e fro mthes e material s becaus e th e aci drelease s lea dfro mth e wall s o f th e containers . Particula r

cosmetic s popula r

amon g som e Orien

ta l an dIndia n ethni c group s contai n hig hpercen tage s o f lea dtha t sometime s ar e absorbe db y user s i n quantitie s sufficien t

t o b e toxic . 12. 4 SUMMAR Y Bloo dlea dlevel s i n homogeneou s huma n popula

tion s hav e almos t

invariabl y bee n foun dt o b e log

normal . A numbe r

o f suc hdat aset s wer e examine d an dthe y displaye dageometri c standar ddeviatio n (GSD ) rangin g fro m1. 3 t o 1.5 . Fro mth e lognorma l distribution , give n amea n bloo dlea dleve l an da n estimate dgeometri c stan dar ddeviation , i t

i s possibl e t o predic t

th e percen tage s o f apopulatio n whos e bloo dlea dlevel s excee d aspecifie dvalue . I t

i s als o possibl e t o estimat e th e likel y increas e in mea n bloo dlea dlevel s fo r a populatio n expose dt o specifi c increase s i n environ

menta l lead . Couplin g thes e tw o procedure s pro vide s ametho db y whic hstandard s ma y b e chose n t o protec t th e healt ho f

th e population . Bloo dlea dlevel s hav e bee n foun dt o exhibi t con siderabl e geographi c variability . Generall y the y ar e lowes t in rura l settings , highe r in suburba n areas , an dhighes t

i n inner-cit y areas . Thes e value s follo w th e presume dlea dexposur e gradient . Bloo dlea d value s wer e als o foun dt o var y b y age , sex , an drace , althoug hin asomewha t mor e comple x fashion . Generally , youn g childre n hav e th e highes t levels , withlittl e differenc e betwee n sexes . I n olde r seg ment s o f th e population , afte r

eliminatin g occupa tiona l exposur e in lea dworkers , male s hav e ahighe r bloo dlea dtha n females . Th e publishe ddat acom parin g th e bloo dlea dlevel s o f variou s racia l an d ethni c group s o f

th e populatio n sugges t tha t black s hav e highe r

bloo dlea dlevel s tha n whites , with Puert o Rican s sometime s at a n intermediat e level . Result s o f

th e numerou s studie s o f environmenta l exposure s o f

ma n hav e indicate dstrongl y tha t ma n doe s indee dtak e u p lea dfro meac hsourc e t o whic h h e i s exposed . Equall y important , thes e studie s hav e show n tha t

th e bloo dlea dleve l i s th e summatio n o f th e absorptio n fro meac ho f thes e sources . Dat afo r th e tw o mos t

widesprea denvironmenta l source s othe r

tha n foo dpermi t

summar y statement s concernin g thei r

quantitativ e relationshi p wit h bloo dlea dlevels : ratio s betwee n bloo dlea dlevel s an dai r lea dexposure s wer e show n t o rang e generall y fro m1: 1 t o 2:1 . Thes e wer e not , however , constan t ove r th e rang e o f

ai r lea dconcentration s encountered . Ther e ar e suggestiv e dat aindicatin g tha t th e ratio s fo r

childre n ar e i n th e uppe r en do f th e rang e an dma y eve n b e slightl y abov e it . Ther e i s als o som e sligh t

suggestio n tha t

th e ratio s fo r

male s ar e highe r

tha n thos e fo r

females . Fo r soi l lea dexposures , aconsisten t associatio n wit hbloo dlea dlevel s ha s bee n established . Childre n expose dt o highe r soi l an dhousedus t

lea d concentration s hav e bee n show n t o hav e elevate d concentration s o f

lea do n thei r

hands , bu t

a n associ

atio n o f elevate dbloo dlea dlevel s wit helevate d han dlea dlevel s ha s no t ye t bee n established . Quan

titatively , bloo dlea dlevel s hav e bee n show n t o in

creas e 3 t o 6 percen t

whe n th e soi l o r

dus t lea dcon ten t i s doubled . Significan t

wate r lea dexposure s i n thi s countr y hav e occurre donl y i n place s usin g leade dpipe s couple dwit hasof

t wate r supply . Suc hexposure s hav e bee n show n t o b e associate dwit hsignifican t 12-3 8elevation s o f bloo dlead . The y hav e als o bee n linke d t o case s o f

menta l retardation . Exposur e t o leade dpain t stil l comprise s aver y seriou s proble mfo r

America n childre n i n urba n set tings . Althoug hne w regulation s governin g th e lea d conten t o f pain t shoul dalleviat e th e proble mi n ne w housing , th e poorl y enforce dregulatio n an dlac k o f regulatio n o f

th e pas t hav e lef

t aheav y burde n o f lea dexposure s fro mpaint . Mos t o f th e studie s o n lea dpoisonin g i n childre n hav e assume da n associ

atio n wit hleade dpaint , bu t ver y rarel y hav e thes e studie s measure dth e amoun t o f exposure . Ther e is , nevertheless , stron g suggestiv e evidenc e tha t th e contributio n fro mthi s sourc e ca n b e ver y significant . Lea dexposur e vi afoo di s though t t o b e th e sourc e o f asignifican t

portio n o f

bloo dlead . Direc t

quan titativ e equation s describin g th e relationshi p o f bloo dt o foo dlea dlevel s hav e no t bee n published , bu t studie s describe din Chapte r 1 0 d o addres s thi s relationship . 12. 5 REFERENCE S FO RCHAPTE R1 2 1 . Yankel , A . J. , I . vo n Lindern . an dS . D . Walter . Th e Silve r Valle y lea dstudy . Th e relationshi p betwee n childhoo d bloo dlea dlevel s an denvironmenta l exposure . J . Ai r Pollut . Cont . Assoc . 27:763-767 . 1977 . 2 . Tepper , L . B . an dL . S . Levin . A surve y o f ai r an dpopula

tio n lea dlevel s i n selecte dAmerica n communities . En

viron . Qual . an dSafe. , Supplemen t II : Lead . 152-195 , 1975 . "3 . Azar , A. , R . D . Snee . an dK . Habibi . A n epidemiologi c ap proac ht o communit y ai r lea dexposur e usin g persona l ai r samplers . Environ . Qual . an dSafe. , Supplemen t II : Lead . 254-288 , 1975 . 4 . Schubert , J. , A . Brodsky . an dS . Tyler . Th e lognorma l functio n a s astochasti c mol do f th e distributio n o f

stron tium-9 0 an dothe r

fissio n product s i n humans . In: Healt h Physics , Vol . 13 . Ne w York , Pergammo n Press . 1967 . p . 1187-1204 . 5 . Snee , R . D . Developmen t o f a n Ai r Qualit y Valu e fo r Lea dfro mCommunit y Studies . E . I . d u pon t d e Nemour s & Co. , Wilmington , Delaware . Technica l Repor t No . PLMR-3-77 . Januar y 1977 . 6 . Johnson . D . E. , J . B . Tillery , J . M . Hosenfeld , an dJ . W . Register . Developmen t o f Analyti c Technique s t o Measur e Huma n Exposur e t o Fue l Additives . Souther n Researc hInstitute , Sa

n Antonio , Texas . Prepare dfo r U.S . Environmenta l Protectio n Agency , Researc h Triangl e Park , Nort hCarolina . Publicatio n No . EPA-650/1-74

- 003 . Marc h1974 . 7 . Johnson , D . E. , J . B . Tillery . an dR . J . Prevost . Level s o f platinum , palladiu man dlea di n population s o f Souther n California . Environ . Hlth . Persp . /2:27-33 , 1975 . 8 . Aitchison , J . an d} . A.C . Brown . Th e Lognorma l Distribu

tion . London , Cambridg e Universit y Press . 1966 . 9 . Johnson , N . L . an dS . Kotz . Continuou s Univariat e Dis

tribution s - I . Boston , Houghto n Miffli n Company . 1970 . p . 112-136 . 10 . Larson . R . I . A Mathematica l Mode l for Relatin g Ai r Qualit y Measurement s t o Ai r Qualit y Standards . U . S . En

vironmenta l Protectio n Agency . Researc h Triangl e Park , Nort hCarolina . Publicatio n No . AP-89 . 1971 . 11 . Lucas , J . M . Effec t o f Analytica l Variabilit y o n Measure

ment s o f Populatio n Bloo dLea dLevels . E . I . d u Pon t d e Nemour s & Co. , Wilmington . Delaware . Technica l Repor t No . PLMR-6-77 . Jun e 1977 . 12 . Goldwater . L . J . an dA . W . Hoover . A n internationa l stud y o f norma l level s o f

lea di n bloo dan durine . Arch . Environ . Hlth . /5:60-63 , 1967 . 13 . Stopps , G . J . Symposiu mfo r ai r qualit y criteri a- lead . J . Occup . Med . 70:550-564 , Septembe r 1968 . 14 . Stopps , G . J . Discussion . Journa l o f Ai r Pollutio n Contro l Association . /9:719-721 , Septembe r 1969 . 15 . Hecker . L. , H . E . Allen . D . D . Dinman , an dJ . V . Neel . Heav y meta l level s i

n acculturate dan dunacculturate d populations . Arch . Environ . Hlth . 29:181-185 , 1974 . 16 . Nordman , C . H . Environmenta l Lea dExposur e i n Fin

land . A Stud y o n Selecte dPopulatio n Groups . Disserta

tion , Universit y o f

Helsinki . Helsinki . 1975 . 17 . Hofreuter , D . H , E . J . Cotcott , R . G . Keenan , an dC . Xin

taras . Th e publi c healt h significanc e o f atmospheri c lead . Arch . Environ . Hlth . 5:568-574 , 1961 . 18 . Creason , J . P. , D . I . Hammer , A . V . Colucci , L . Priester . an dJ . Davis . Bloo dtrac e metal s i n militar y recruits . Souther n Med . J . 69:289-293 , Marc h1976 . 19 . Scanlon , J . Umbilica l cor dbloo dlea dconcentration : Relationshi p t o urba n o r suburba n residenc y durin g gesta tion . Amer . J . Dis . Child . /2/:325-326 , Apri l 1971 . 20 . Gershanik . J . J. , G . G . Brooks , an dJ . A . Little . Feta l bloo dlea dvalue s i

n arura l area . J . Pediatr . 84:]12-113 , Januar y 1974 . 21 . Cohen , C . J. , G . N . Bowers , an dM . L . Lepow . Epidemiolog y o f

lea dpoisoning . J . Amer . Med . Assoc . 22(3:1430-1433 . Decembe r 1973 . 22 . Hasselblad . W . an dW . Nelson . Additiona l analyse s o f th e Seve n Cit y Lea dStudy . Environ . Qual . an dSafe. , Supple

men t II : Lead . 147-151 , 1975 . 23 . Haegar-Aronsen , B. , M . Amdulla , an dB . Frisilett . Effec t o f lea do n o-aminolevulini c aci ddehydras e activit y i n re d bloo dcells . Arch . Environ . Hlth . 25:440-445 , 1971 . 24 . Zuilo , N. , A . M . Griffin , an dE . C . Vigliani . Th e conten t o f lea di n bloo dan durin e o f

adults , livin g i n Milan , no t occupationall y expose dt o lead . Amer . Ind . Hyg . Assoc . J . 5/:92-95 . 1970 . 25 . Secchi , G . C . an dL . Alessio . Laborator y result s o f som e biologica l measure s i

n worker s expose dt o lead . Arch . En

viron . Hlth . 29:351-354 , 1974 . 26 . Secchi . G . C , L . Allesio , an dG . Cambriogglie . Ricerch e sul l 'attivit aAL A - derclrisie aerithrocitar i d i soggett i no n espost i acontatt o professional e ee n plomb o e dabitant i i n zon e rural i e durbane . Med . Lav . (Milan) . 62:435-450 , 1971 . 27 . Boudene , C , F . Arsue , an dJ . Neininger . Etud e de s tou x d e plom b dou s fai r

e t dan s lapopulatio n e n France . In: Pro

ceeding s o f

Internationa l Symposiu mo n Environmenta l Lea dResearch , Dubrovnik , Yugoslavia . Ma y 14-15 , 1975 . 28 . Kubota , J. , V . A . Lazar , an dF . Losel . Copper , zinc , cad

mium , an dlea di n huma n bloo dfro m1 9 location s i n th e Unite dStates . Arch . Environ . Hlth . /6:788-793 , 1968 . 12-3 929 . McLaughlin , M. , A . L . Linch , an dR . D . Snee . Longitudina l studie s o f lea dlevel s i n aU . S . population . Arch . Environ . Hlth . 27:305-311 , Novembe r 1973 . 30 . Fine . P . R. , C . W . Thomas , R . H . Suho , R . E . Cohnberg , an dB . S . Flashner . Pediatri c bloo dlea dlevels . A stud y i n 1 4 Illinoi s citie s o f

intermediat e population . J . Amer . Med . Assoc . 227:1475-1479 , Septembe r 1972 . 31 . Baker , E . L. . C . G . Hayes . P . J . Landrigan , R . T . Leger , J . L . Handke , an dJ . M . Harrington . A nationwid e surve y o f heav y meta l absorptio n i n childre n livin g nea r primar y copper , lea dan dzin c smelters . Amer . J . Epid . 706:261-273 , 1977 . 32 . Joselow , M . M. , J . E . Bauta . W . Fisher , an dJ . Valentine . Environmenta l contrasts : Bloo dlea dlevel s o f childre n i n Honolul u an dNewark . J . Environ . Hlth . 57:10-13 , 1975 . 33 . Landrigan , P . J. , S . H . Gehlbach , B . F . Rosenblum , J . M . Shoults , R . M . Candelaria , W . M . Barthel , J . A . Liddle . A . L . Smrek , N . W . Staehling , an dJ . F . Sanders . Epidemi c lea dabsorptio n nea r

a n or e smelter : Th e rol e o f particu

lat e lead . Ne w Englan dJ . Med . 292:123-129 , 1975 . 34 . Johnson , D . E. , R . J . Prevost , J . B . Tillery , K . J . Timball . an dJ . M . Hosenfeld . Epidemiologi c Stud y o n th e Effec t o f Automobil e Traffi c o n th e Bloo dLevel s o f Person s i

n Selecte dAg e Groups . Southwes t Researc h Institute , Sa n Antonio , Texas . Prepare dfo r U . S . Environmenta l Protec

tio n Agency , Researc hTriangl e Park , Nort h Carolin a unde r Contrac t

No . 68-02-2227 . 1977 . 35 . Simpson , J . M. , J . L . Clark , R . S . Challop , an dE . B . Mc

Cabe . Elevate dbloo dlevel s i n childre n - a27-cit y neigh

borhoo dsurvey . Hlth . Service s Report . 85:419-422 , Ma y 1973 . 36 . Elam , H . P. , W . Boggs , J . P . Bedeuka . an dJ . Christian . Seasona l approac ht o th e etiolog y o f childhoo durba n en vironmen t

o f lea dpoisoning . Pediatr . Digest . 11-20 , Jul y 1977 . 37 . Adebonojo , F . O . Hematologi c statu s o f urba n blac k childre n i

n Philadelphia : Emphasi s o n th e frequenc y o f anemi aan delevate dbloo dlea dlevels . Clin . Pediatr . 75:874-888 , Octobe r

1974 . 38 . Billick . I. , A . Curran , an dD . Shier . Presentatio n t o th e U . S . EP A Lea dSubcommitte e o f th e Scienc e Advisor y Board , Washington , D . C „ Octobe r 7 , 1977 . 39 . Haas , T „ K . Mache , K . H . Schuller , W . Mache , an dH . Valentine . Investigation s int o ecologica l lea dlevel s i n children . (Unlers heichuge n eibe r di e okologisch e Bleilielastun g imKendesalterl) . Zbl . Bakt . Hyg . I . Abt . Orig . B . /56:353-360 , 1972 . 40 . Surve y o f

Lea di n th e Atmospher e o f Thre e Urba n Com

munities . U . S . Departmen t o f Health . Education , an d Welfare . Raleigh . Nort hCarolina . Publicatio n No . 999

- AP-12 . 1970 . 41 . Tsuchiya , K. , M . Sugita . Y . Seki , Y . Koboryashi , M . Hori , an dC . B . Park . Stud y o f lea dconcentratio n i

n atmospher e an dpopulatio n i n Japan . Environ . Qual . an dSafe. , Sup

plemen t II : Lead . 95-147 , 1975 . 42 . Goldsmith , J . R . Foo dChai n an dHealt hImplication s o f Airborn e Lead . U . S . Departmen t o f Commerce , Washing

ton , D . C . NTI S No . PB-248745 . 1974 . 43 . Galke , W . A. , D . I . Hammer , J . E . Keil , an dJ . W . Law

rence . Environmenta l determinant s o f lea dburden s i n children . In: Proceeding s o f th e Internationa l Conferenc e o n Heav y Metal s i n th e Environment . Nationa l Technica l Informatio n Service , Springfield , Virginia . Octobe r 1975 . 44 . Guinee . V . J . Epidemiologi c studie s o f lea dexposur e i n Ne w Yor k

City . In: Environmenta l Healt h Aspect s o f Lead . Luxembourg . Commissio n o f th e Europea n Com

munities . 1973 . p . 763-772 . 45 . Anderson , D . G . an dJ . L . Clark . Neighborhoo dscreenin g i n communitie s throughou t th e natio n fo r

childre n wit h elevate dbloo dlea dlevels . Environ . Hlth . Persp . Expt . /(7):3-6 , 1974 . 46 . Repor t

o f th e Swis s leade dgasolin e commissio n t o th e Federa l Counci l o n it s activitie s durin g th e perio d 1947-1960 . Mit t

Gebret e Lebensmi t

Hyg . 52:135-144 , 1961 . (Englis htranslation . Universit y o f Cincinnati , Ket

terin g Laboratory . Cinn. , Ohio , 1961. ) 47 . Manton , W . I . Source s o f lea di n blood . Arch . Environ . Hlth . 52:149-159 , 1977 . 48 . Garibaldi . P. . S . Facchetti , A . Quagliardi , G . Vanini , P . P . Gaddo , M . D e Bortoli , an dP . Gaglione . Petrol s additi

vate dwit h isotopicall y differentiate dlea dproposa l o f a n experimen t

t o estimat e th e incidenc e o f traffi c o n th e en vironmen t

pollutio n b y lea d- Firs t experimenta l results . In: Proceeding s Internationa l Symposiu mRecen t Ad

vance s i n th e Assessmen t

o f th e Healt h Effect s o f

Environ

menta l Pollutio n Volum e III . Luxembourg , Commissio n o f th e Europea n Communities . 1975 . p . 1287-1299 . 49 . Johnson , D . E. , J . B . Tillery , D . E . Camann , an dJ . M . Hosenfeld . Baselin e Level s o f Platinu man dPalladiu mi n Huma n Tissue . U . S . Environmenta l Protectio n Agency , Researc hTriangl e Park , Nort h Carolina . Publicatio n No . EPA-600/1-76-019 . 23 6 p . 50 . Snee , R . D . Evaluatio n o f Studie s o f

th e Relationshi p be

twee n Bloo dLea dan dAi r Lead . E . I . d u Pon t

d e Nemour s & Co.,'Wilmington , Delaware . Technica l Repor t No . PLMR-8-77 . Apri l 1977 . 51 . Caprio . R . J. . H . L . Margulis . an dM . M . Joselow . Lea d absorptio n i n childre n an dit s relationshi p t o urba n traffi c densities . Arch . Environ . Hlth . 25:195-197 , 1974 . 52 . Daines , R . H. . D . W . Smith , A . Feliciano . an dJ . R . Trout . Ai r level s o f

lea dinsid e an doutsid e o f homes . Ind . Med . an dSurg . 47:26-28 , 1972 . 53 . Thomas , H . V. , B . K . Milmore , G . A . Herdbreder , an dB . A . Kogan . Bloo dlea di n person s livin g nea r freeways . Arch . Environ . Hlth . /5:695-702 . 1976 . 54 . Waldron , H . A . Lea dlevel s i n bloo do f resident s nea r

th e M6-A38(M ) interchange , Birmingham . Nature . 255:345-346 , Januar y 1975 . 55 . Barry , P . S . Lea dlevel s i n blood . Nature . 258:775 , Decembe r

1975 . 56 . Knelson . J . H. , R . J . Johnson , F . Coulston , L . Goldberg , an dT . Griffin . Kinetic s o f respirator y lea duptak e i n humans . In: Environmenta l Healt hAspect s o f Lead . Lux

embourg , Commissio n o f th e Europea n Communities . Ma y 1973 . p . 391 . 57 . Jones , R . D. , B . T . Commins , an dA . Cernik . Bloo dlea d an dcarboxyhemoglobi n level s i n Londo n tax i drivers . Lancet . 2:302-303 , Augus t 1972 . 58 . Flindt . M . L . H. . E . King , an dD . B . Walsh . Bloo dlea d an derythrocyt e 8-aminolevulini c aci ddehydratas e level s i n Mancheste r

tax i drivers . Brit . J . Ind . Med . 55:79-84 , 1976 . 59 . Huma n lea dabsorptio n - Texas . Cente r fo r Diseas e Con

trol . Morbidit y an dMortalit y Wkly . Rept . 22(49):405-407 , Decembe r 1973 . 12-4 060 . Helen aValley , Montana , Are aEnvironmenta l Pollutio n Study . U . S . Environmenta l Protectio n Agency , Researc h Triangl e Park , Nort hCarolina . Publicatio n No . AP-91 . Januar y 1972 . 61 . Hammer , D . I. , J . F . Finklea , R . H . Hendricks , T . A . Hin

ners , W . B . Riggan , an dC . M . Shy . Trac e metal s i n huma n hai r a s asimpl e epidemiologica l monito r o f environmen

ta l exposure . In: Trac e Substance s i n Environmenta l Health . Hemphill . D . D . (ed.) . Columbia . Univ . o f Missour i Press . 1973 . p . 25-38 . 62 . Landrigan , P . J. , E . L . Baker , Jr. , R . G . Feldman . D . H . Cox , K . V . Eden , W . A . Orinsken . J . A . Mather , A . J . Yankel , an dI . H . vo n Lindern . Increase dlea dabsorptio n wit hanemi aan dslowe r nerv e conductio n i

n childre n nea r alea dsmelter . J . Pediatr . 89(6):904-910 , Decembe r 1976 . 63 . vo n Lindern , I . an dA . J . Yankel . Presentatio n t o th e Shoshon e Heav y Metal s Projec t Committee . In: Shoshon e Lea dHealt hProjec t

Wor k Summary . Januar y 1976 . 64 . Djuric . D. . Z . Kerin . L . G . Leposavic . L . Novak , an dM . Kop . Environmenta l contaminatio n b y lea dfro mamin e an dsmelter . Arch . Environ . Hlth . 25:275-279 . 1971 . 65 . Fugas , M. , B . Wilder , R . Paukovic . J . Hrsak . an dD . Steiner-Skreb . Concentratio n level s an dparticl e siz e dis

tributio n o f

lea di n th e ai r o r a n urba n an da n industria l are aa s abasi s fo r

th e calculatio n o f

populatio n exposure . In: Environmenta l Healt hAspect s o f Lead . Luxembourg , Commissio n o f

th e Europea n Communities . 1973 . p . 961-968 . 66 . Graovac-Leposavic , L . Environmenta l lea dcontamina

tio n o f Mez aValley . Stud y o n lea dexposur e o f popula

tion . In: Environmenta l Healt hAspect s o f Lead . Luxem

bourg , Commissio n o f

th e Europea n Communities . 1973 . p . 685-705 . 67 . Milic , S. , M . Stankovic , V . Delic . an dV . Djordjevic . Biochemica l parameter s i n evaluatio n o f environmenta l lea dexposure . In: Environmenta l Healt hAspect s o f Lead . Luxembourg , Commissio n o f th e Europea n Communities . 1973 . p . 561-568 . 68 . Djuric , S. . L . Graovac-Leposavic . S . Milic , an dL . Senicar . Lea dcontaminatio n o f Mez aValley . Lea dmobilizatio n wit hCa-Na 2 -EDT A fro mth e bodie s o f inhabitants . Prac . Lek . (Prague) . 24:49-50 , 1972 . 69 . Fugas , M. , D . Majic , R . Paukovic , B . Wilder , an dZ . Skuric . Biologica l Significanc e o f som e Metal s a s Ai r Pollutants . Departmen t o f Health . Education , an d Welfare , Washington , D . C . Prepare dfo r U . S . Environ

menta l Protectio n Agency , Researc hTriangl e Park , Nort h Carolina , unde r

Interagenc y Agreemen t No . 02-302-3 . 1974 . 70 . Djordjevic , S . an dM . Stankovic . Ai r pollutio n an dcom muna l saturnis mi n Mal o Rudar e Village . Higijena . (Belgrade) . /2:35-44 , I960 . 71 . Oyanguren , H . an dE . Perez . Poisonin g o f a n industria l origi n i n acommunity . Arch . Environ . Hlth . 75 : 185-189 , 1966 . 72 . Secchi , G . C , L . Alessio , G . Cambiaghi , an dF . Andreolet

ti . ALA-dehydratas e activit y o f erythrocyte s an dbloo d lea dlevel s i

n "critical " populatio n groups . In: Environ

menta l Healt hAspect s o f Lead . Luxembourg . Commissio n o f th e Europea n Communities . 1973 . p . 595-602 . 73 . Mclntire , M . S . an dC . R . Angle . Ai r lea dbloo dlea di

n G-6-P D deficien t

blac k schoo l children , In: Environmen

ta l Healt hAspect s o f

Lead . Luxembourg , Commissio n o f th e Europea n Communities . 1973 . p . 749-761 . 74 . Angle , C . R . an dM . S . Mclntire . Lea di n air , dustfall , soil , housedust , mil k

an dwater : Correlatio n wit h bloo dlea do f urba n an dsuburba n schoo l children . In: Trac e Substance s i n Environmenta l Health-VII I Proceeding s o f th e 8t hAn

nua l Conferenc e o n Trac e Substance s i n Environmenta l Health . Columbia . Jun e 11 , 1974 . 75 . Angle , C . R . an dM . S . Mclntire . I s busin g goo dfo r you r bloo dlead . Abstrac t

fo r 2n dAnnua l French-America n Congres s o n Clinica l an dAnalytica l Toxicology . St . Adele , Canada . Augus t 1-4 , 1977 . p . 14 . 76 . Angle , C . R . an dM . S . Mclntire . Environmenta l control s an dth e declin e o f

bloo dlead . Arch . Environ . Hlth . (I n press. ) 1977 . 77 . Johanson , W . C . an dJ . P . Luby . A Repor t o n aStud y t o Determin e th e Bloo dLea dLevel s i n Dalla s Children . Dalla s Healt hDepartment , Dallas , Texas . 1972 . 78 . Roberts , T . M. , T . C . Hutchinson . J . Paciga . A . Chat

topadhyay , R . E . Jervis , an dJ . Va n Loon , Lea dcon taminatio n aroun dsecondar y smelters : Estimatio n o f dis

persa l an daccumulatio n b y humans . Science . 786: 1 120-1123 , Decembe r 1974 . 79 . Repor t

o f th e Lea dDat aAnalysi s Tas k Force . Ministr y o f th e Environment , Toronto , Ontario . Canada . 1975 . p . 169 . 80 . Horn . J . D . Significan t Overestimatio n o f

Bloo dLea d Level s i n Practic e - A Consequenc e o f Usin g th e Micr o Metho do f

Bloo dLea dAnalysis . Universit y o f Wester n Ontario . (Prepublicatio n draft. ) Augus t 1976 . 81 . Nordman , C . H. , S . Hernberg , J . Nikkanen . an dA . Rybanen . Bloo dlea dlevel s an derythocyt e 8

- aminolevulini c aci ddehydratas e activit y i n peopl e livin g aroun dasecondar y lea dsmelter . Work-Environ . Hlth . 70:9-25 , 1973.

- 82 . Zykova , A . S . Pollutio n o f atmospheri c ai r

wit h lea dan d it s effec t o n th e healt ho f

th e population . USS RLit . o n Ai r Poll , an dRelate dOccup . Dis . (Washington) . 7:55-62 , I960 . 83 . Gusev , M . I . Ne w studie s o n th e effect s o f lo w lea dcon centration s o n th e huma n organism . Limit s o f Allowabl e Concentration s o f

Atmospheri c Pollutants . (Washington) . 5:19-28 , 1962 . 84 . Dequidt , J. , D . Vaast . an dA . Lespagnol . Saturnis m hazard s i n lea dprocessin g plan t areas . (Risque s d'impregnatio n saturnin e a u voisinag e d'usine s d e traite

men t d u plomb. ) Poll . Atmos . (Paris) . /5:289-292 , 1971 . 85 . DeRosa . E . an dF . Gobbato . Non-professiona l saturnism : A pollutio n epidemi c fro mindustria l emissions . (Epidemi ape r

inquinament o d aeffluent i industrial. ) In

gien e Moderna . (Parma) . 65:472-484 , 1970 . 86 . Griffin , T . B. , F . Coulston . H . Wills , J . C . Russell , an dJ . H . Knelson . Clinica l studie s o n me n continuousl y expose d t o airborn e particulat e lead . Environ . Qual . an dSafe. , Supplemen t

II : Lead . 221-240 , 1975 . 87 . Goldsmith , J . R . an dA . C . Hexter . Respirator y exposur e t o lead , epidemiologi c experimenta l dose-repons e rela

tionships . Science . /58:132-134 . 1967 . 88 . Kehoe , R . A . Th e metabolis mo f lea di n ma n i n healt han d disease . Th e Harbe n Lectures . R . Inst . Publi c Healt hHyg . 24:81-97 . 129-143 , 177-203 . 1961 . 89 . Gross , S . B . Statemen t relatin g t o th e Nationa l Ambien t Ai r Qualit y Standar dfo r

Lead . Presente dt o Criteri aan d Specia l Studie s Office , Healt hEffect s Researc h Laborato

ry , Researc hTriangl e Park , Nort hCarolina . Apri l 11 , 1977 . 12-4 1P.5 1

90 . Rabinowitz , M . B . Lea dcontaminatio n o f th e biospher e b y huma n activity . A stabl e isotop e study . Ph.D . Thesis , Universit y o f

California , Lo s Angeles . 1974 . 12 0 p . 91 . Rabinowitz . M . B „ G . W . Weatherwill , an dJ . D . Kapple . Kineti c analysi s o f

lea dmetabolis mi

n health y humans . J . Clin . Invest . 58:260-270 , 1976 . 92 . Chamberlain , A . C , W . S . Clough , M . J . Heard , J . Newton , A . N . B . Stott , an dA . C . Wells . Uptak e o f lea db y inhala

tio n o f moto r exhaust . Proc . R . Soc . Londo n Ser . B . 792:77-110 , 1975 . 93 . Chamberlain , A . C . W . S . Clough , M . J . Heard , D . Newton , A . N . B . Stott , an dA . C . Wells . Uptak e o f inhale d lea dfro mmoto r

exhaust . Postgrad . Med . J . 5/:790-794 , 1975 . 94 . Williams , M . K. , E . King , an dJ . Walford . An investigatio n o f lea dabsorptio n i n a n electri c accumulato r factor y wit h th e us e o f

persona l samplers . Brit . J . Indus . Med . 26:202-216 , 1969 . 95 . Bridbord . K . C . Huma n Exposur e t o Lea dfro mMoto r Vehicl e Emissions . U . S . Departmen t o f Health . Educa

tion , an dWelfare , Washington , D . C . NIOS H Publicatio n No . 77-145 . Januar y 1977 . 9 4 p . 96 . Williams . D . A . A tes t fo r difference s betwee n treatmen t mean s whe n severa l dos e level s ar e compare dwit hazer o dos e control . Biometrics . 27:103-117 . Marc h 1971 . 97 . Kendall , M . G . an dA . Stuart . Th e Advance dTheor y o f Statistics , Vol . 2 . Ne w York . Griffin . 1961 . p . 377 . 98 . Baker , E . L . Presentatio n t o th e EP A Scienc e Advisor y Board' s Subcommitte e o n Scientifi c Criteri afo r Environ

menta l Lead . Washington , D . C . Januar y 31 , 1977 . 99 . Fairey , F . S . an dJ . W . Gra y III . Soi l lea dan dpediatri c lea dpoisonin g i n Charleston . S . C . J . Sout hCarolin aMed . Assoc . 66:79-82 . 1970 . 100 . Barltrop , D. . C . D . Strehlow , J . Thornton , an dJ . S . Webb . Significanc e o f

hig hsoi l lea dconcentration s fo r childhoo d lea dburdens . Environ . Hlth . Persp . Expt . Iss . 7:75-84 , 1974 . 101 . Barltrop , D . Significanc e o f lea dcontaminate dsoil s an d dust s fo r huma n populations . Arh . Hig . Rad aToksikol . 26(Suppl):81-93 , 1975 . 102 . Creason , J . P. . T . A . Hinners , J . E . Bumgarner , an dC . Pinkerton . Trac e metal s i n hai r a s relate dt o exposur e i n metropolita n Ne w York . Clin . Chem . 27:603-612 , 1975 . 103 . Sayre , J . W. . E . Charney , J . Vostal , an dD . B . Pless . Hous e an dhan ddus t

a s apotentia l sourc e o f childhoo dlea dex posure . Amer . J . Dis . Child . 727:167-170 , 1974 . 104 . Te r Harr , G . an dR . Aronow . Ne w informatio n o n lea di n dir t an ddus t

a s relate dt o th e childhoo dlea dproblem . Environ . Hlth . Persp . Expt . Iss . 7:83-89 , 1974 . 105 . Duggan . M . J . an dS . Williams . Lead-in-dus t i n cit y streets . In: Th e Scienc e o f th e Tota l Environment . Amster

dam , Elsevie r

Publishin g Company . 1977 . 106 . Lepow , M . L. , L . Brickman , M . Tillette , S . Markowitz , R . Robine , an dJ . Kapesh . Investigatio n int o th e source s o f lea di n th e environmen t o f urba n children . Environ . Res . 70:415-426 , 1975 . 107 . Shellshear . F . D . Lea dpoisonin g i n childhood : A cas e re por t wit henvironmenta l duplications . Ne w Zealan dMed . J . 78:251-254 . 1973 . 108 . Vostal , J „ E . Taves . J . W . Sayre , an dE . Charney . Lea d analysi s o f

th e hous e dust : A metho dfo r th e detectio n o f anothe r sourc e o f

lea dexposur e i n inne r

cit y children . En

viron . Hlth . Persp . 7:99-102 , 1974 . 109 . 110 . 111 . 112 . 113 . 114 . 115 . 116 . 117 .

118 . 119 .

120 . 12 1

122 . 123 . 124 . 125 126 .

127 . Chisohlm , J . J. , Jr . an dH . E . Harrison . Th e exposur e o f childre n t o lead . Pediatr . 78:943-958 , 1956 . Barltrop , D . an dN . H . P . Killala . Feca l excretio n o f lea d b y children . Lancet . 2:1017-1019 , 1967 . Kolbye , A . C , K . R . Mahaffey , J . A . Fiorino , P . C . Cor

neliussen , an dC . F . Jelinek . Foo dexposur e t o lead . En

viron . Hlth . Persp . 7:65-74 , 1974 . Mahaffey , K . R . Quantitie s o f lea dproducin g healt h effect s i n humans : Source s an dbioavailability . Environ . Hlth . Persp . 79:285-296 , 1977 . Complianc e Progra mEvaluatio n F Y 197 4 Heav y Metal s i n Food s Surve y (7320.13C ) (Chemica l Contaminant s Project) . Burea u o f

Foods , U . S . Foo dan dDru g Adminis

tration , Washington , D . C . Jun e 19 , 1975 . 9 9 p . Beattie . A . D. , J . H . Dagg , A . Goldberg , I . Wang , an dJ . Ronald . Lea dpoisonin g i n rura l Scotland . Brit . Med . J . 2:488-491 , 1972 . Beattie . A . D. , M . R . Moore , W . T . Devenay , A . R . Miller , an dA . Goldberg . Environmenta l lea dpollutio n i n a n ur ba n sof t wate r area . Brit . Med . J . 2:491-493 , 1972 . Crawford , M . D . an dT . Crawford . Lea dconten t o f bone s i n ahar dan dsof

t wate r area . Lancet . 7:699-701 , 1969 . D e Graeve , J. , D . Rondia , an dP . Jamin . Lea dconcentra tion s i n drinkin g wate r an dbloo dlea dlevel s i n a n adul t population . In: Proc . Inter . Symp . o n Recen t Advance s i n th e Assessmen t

o f th e Healt h Effect s o f Environmenta l Pollution , II . Luxembourg , Commissio n o f th e Europea n Communities . 1975 . p . 523-535 . Worth , D . Lea di n drinkin g water , apubli c healt hprob

le mwit h asolution . J . Amer . Publi c Healt hAssoc . (I n press) . 1977 . Greathouse . D . G. , G . F . Craun , an dD . Worth . Epidemiologica l stud y o f th e relationship s betwee n lea di n drinkin g wate r

an dbloo dlea dlevels . In: Trac e Substance s i n Environmenta l Health . X . D . Hamphill , (ed.) . Colum

bia , Universit y o f

Missour i Press . Lin-Fu . J . S . Vulnerabilit y o f childre n t o lea dexposur e an dtoxicity . Ne w Englan dJ . Med . 289:1229-1233 , 1289-1293 . 1973 . Berger . H . W . Th e NB S lea dpain t poisonin g project : Housin g an dothe r

aspects . Nationa l Burea u o f Standards , Gaithersburg , Maryland . Technica l Not e No . 759 . Febru

ar y 1973 . Bird , D . Ne w Yor k

Times , Augus t

8 , 1971 . Lea dPain t

Surve y Samplin g Pla n an dPreliminar y Screen

in g Repor t

10958 . Nationa l Burea u o f Standards , Gaithersburg , Maryland . 1973 . A Repor t t o Congres s i n Complianc e wit h th e Lea dBase d Pain t Poisonin g Preventio n Act . Consume r Produc t Safety Commission , Washington , D . C . Decembe r 1974 . Recommendation s fo r

th e Preventio n o f

Lea dPoisonin g i n Children . Assembl y o f Lif e Sciences , Nationa l Academ y o f Sciences , Washington , D . C . Jul y 1976 . 8 5 p . Shier , D . R . an dW . G . Hall . Analysi s o f Housin g Dat a Collecte di n aLead-Base dPain t Surve y i n Pittsburgh , Pennsylvania . Nationa l Burea u o f Standards , Washington , D . C . (I n preparation. ) 1977 . Hall , W. , T . Ayers , an dD . Doxey . Surve y Plan s an dDat a Collectio n an dAnalysi s Methodologies : A s aResul t o f a Pre-Surve y fo r

th e Magnitud e an dExten t o f th e Lea d Base dPain t

Hazar di n Housing . Nationa l Burea u o f Stan

dards , Gaithersburg , Maryland . Repor t No . NBSI R 74-426 . Januar y 1974 . 12-4 2128 . Urban , W . D . Statistical Analysi s o f Bloo dLea

dLevel s o f Childre n Surveyedi

n Pittsburgh , Pennsylvania : Analytical Methodolog y andSummar y Results . Fina

l contrac t re port . Contrac t

IAA-H-35-75 . Departmen t o f Housin g and Urba n Development , Washington , D . C . Apri l 1976 . 129 . Reece , R . M. , J . A . Reed , C . S . Clark , R . Angoff , K . R . Casey , R . S . Challop , andE . A . McCabe . Elevate dbloo d lea dlevel s andth e in situ analysi s o f wall paint

b y X-ra y fluorescence . Amer . J . Dis . Child . 724:500-502 , 1972 . 130 . Tyler , R . L . Philadelphi acombat s "silen t epidemic " i

n th e "ghetto " leadpoisonin g control . J . Environ . Hlth . 55:64-71 , 1970 . 131 . Hopkins , D . R . andV . N . Houk . Federally-assiste d screenin g project s fo

r childhoo dlea

dpoisonin g control : Th e firs t thre e year s (July 1972-Jun e 1975) . Amer . J . Publi c Hlth . 66:485-486 , Ma y 1976 . 132 . Morbidity andMortality Weekl y Report . Departmen t

o f Health , Education , andWelfare , Rockville , Maryland . February 11 , 1977 . 1 33 . Martin , A . E. , F . A . Fairweather , R . St . J . Buxton , andR . M . Roots . Recent

Epidemiological Studie s o f Environ

menta l Lea do f Industria l Origin . Luxembourg , Commis

sion o f th e Europea

n Communities . 1975 . 134 . Medical Aspect s o

f Lea dAbsorptio n i

n Industria l Pro

cesses . Lea

dDevelopment

Assoc , London , England . 1973 . 135 . Baker , E . L. , D . S . Folland , T . A . Taylor , M . Frank , W . Peterson , G . Lovejoy , D . Cox . J . Housworth , andP . J . Landrigan . Lea

dpoisonin g i

n childre n o

f lea dworkers ; hous e contaminatio n wit

hindustrial dust . Ne

w Englan dJ . Med . 296:260-261 , 1977 .

12-4 3P.5 3



## 13 . EVALUATIO N O F HUMA N HEALT H RISK S 1 

## FRO M EXPOSUR E T O LEA D AN D IT S COMPOUND S 13. 1 INTRODUCTIO N Th e precedin g chapter s o f thi s documen t

hav e de

scribe dlea dproduction , th e eonomic s o f lea d utilization , th e dispersio n o f lea di n th e environ

men t —particularl y in air , dust , an dsoi l —and , finally , hav e reviewe dth e effect s o f lea do n th e healt ho f man . Althoug hattemptin g t o relat e thes e variou s issue s t o on e another , thi s chapte r specificall y wil l attemp t t o asses s an dt o quantitat e th e healt heffect s tha t

aris e fro mexposur e o f ma n t o lea din th e environmen t and , mor e precisely , fro m exposur e t o lea din air . Si x centra l question s t o b e addresse dar e a s follows : 1 . Wha t ar e th e source s o f

lea din th e environ

ment ? (Section s 13. 2 an d13.3 ) 2 . Wha t ar e th e route s an dmechanism s b y whic hlea dfro mthes e source s enter s th e body ? (Section s 13. 2 an d13.3 ) 3 . Wha t par t d o averagin g time s fo r thes e ex posure s play ? (Sectio n 13.4 ) 4 . Ho w doe s th e bod y respon dt o th e entranc e o f lead ? (Sectio n 13.5 ) 5 . Ar e ther e group s withi n population s whic h ar e particularl y vulnerabl e t o lead ? (Sectio n 13.6 ) 6 . Wha t i s th e magnitud e o f

th e ris k exposure s in term s o f

th e numbe r

o f person s expose din variou s subgroup s o f

populations ? (Sectio n 13.7 ) Eac ho f th e abov e question s i s addresse dseparatel y a s asubsectio n o f

thi s chapter , an dth e relevan t sec tio n i s note dbesid e eac hquestion . No w tha t

th e question s t o b e addresse di n thi s treatmen t

o f ris k assessmen t

hav e bee n outlined , it

i s necessar y t o defin e th e term s whic hwil l b e employed . Thes e include : 1 . Dose i s th e amoun t

o r concentratio n o f

a chemica l tha t

i s presente dove r

tim e t o an organism , organ , cell , o r subcellula r

compo nent . Ideally , dos e shoul db e define da s th e amoun t o r concentratio n o f

th e chemica l a t

a specifi c intracellula r

sit e o f effect . 2 . External dose i s th e amoun t

o f th e contami

nan t in th e externa l environmen t (air , water , food , etc. ) t o whic hhuman s ar e exposed . 3 . Effective dose o r

internal dose i s th e amoun t o f th e contaminan t

absorbe db y th e body . 4 . Effect i s abiologi c chang e whic hresult s fro m exposur e t o achemical . 5 . Dose-effect

relationship i s aquantitativ e relationshi p betwee n th e dos e an dth e specifi c effec t

tha t i s establishe dafte r

grada

tion s in th e severit y o f a n effec t

hav e bee n measured . 6 . Critical

effect i s th e firs t

advers e functiona l change , reversibl e o r

irreversible , t o b e cause db y exposur e t o aparticula r chemical . 7 . Subcritical

effect i s achang e tha t

i s demonstrabl e b y biochemica l o r othe r test , bu t whic hdoe s no t

appea r t o impai r

func

tion ; som e suc hchange s ma y b e adaptiv e i n nature . 8 . Critical

dose o r critical concentration i s th e leve l o f achemica l a t

whic hth e critica l effec t appears . 9 . Critical

organ i s th e orga n whic hmanifest s th e critica l effect ; i t

nee dno t

b e th e orga n withth e highes t

concentratio n o f

th e chemi

ca l no r tha t whic hultimatel y suffer s th e mos t seriou s injury . Dose-effec t

relationship s will var y amon g th e member s o f

apopulation . Respons e i s th e propor tio n o f th e populatio n tha t

manifest s aparticula r effec t at aparticula r

dos e level. 1 Thi s i s amor e restrictiv e definitio n o f respons e tha n tha t

use di n bioassa y a s describe db y Finney. 2 Th e relationshi p betwee n dos e an dth e proportio n respondin g i s th e dose-respons e relation , whic hwil l mos t commonl y b e expresse db y asigmoid-shape dcurve . 13. 2 SOURCES , ROUTES , AN D MECHAN ISM S O F ENTR Y 13.2. 1 Source s O f th e estimate d161,22 5 metri c ton s o f lea demit

13- 1P.5 4



### te dint o th e atmospher e i n 1975 , th e combustio n o f gasolin e additive s an dwast e oi l accounte dfo

r 9 5 percen t of tota l inventorie demissions . Eac ho f th e remainin g emissio n source s account s fo r onl y a smal l part o f th e tota l quantity o

f lead , bu t ha s th e potentia l o

f creatin g localize dsituation s o f highair leadconcentrations , e.g. , primary lea dsmelters . Onc e leadi s introduce dinto th e air i t undergoe s a variety o f processe s includin g dr

y deposition , pre cipitation , an dresuspension . Thes e processe s resul t i n avariabl e proportio n o

f lea dbein g retaine di

n th e air an dthe n bein g distribute dover awide area . Othe r portion s ar e deposite don land , i n dust , an do

n water , resultin g i

n increase dleadconcentration s i n each . Othe r use s o f lea dresul t i n additiona l huma

n ex posure . Th e additio n o

f leadt o paint

make s lea

d directl y availabl e b

y ingestio n o

f paint chip s and paint-saturate dplaster . I n additio n i

t become s in

directl y availabl e throug hdus t contaminate dwit

h leadfreedb

y th e weatherin g proces s o f paint . Thi s primary sourc e i s currentl y unde r regulation , bu t

a vas t stock o f housin g painte dwit

hhigh-lead-conten t pain t stil l exists . Lead' s malleability an dductility hav e resulte di n th e us e o f thi s metal i

n pipe s fo r carryin g drinkin g water . When suchpipe s ar e usedi n area s wit

hsof t water o f low pH , apotentia l exist s fo r heavy lea

d contaminatio n o

f drinkin g water . It

i s difficult

t o estimat e th e overal l magnitud e of thi s danger , bu t ther e hav e been specifi c localize dexample s i n th e Unite dStates . A final quantitativel y significant sourc e o f leadi s th e huma n diet . Leadpresen t

i n foodstuff

s i s th e su m o f th e amoun t

presen t i n th e ra w foodstoc k

an do f lea dintroduce dvi aprocessin g an dpackaging . Can

nedproduct s sucha s vegetable s an dmil k hav e been show n t o contai n higher

quantitie s o

f leadthan th e sam e product s package ddifferently . Thi s i s due , i n part , t o th e presenc e o

f leadsolde r

i n th e seam s o

f cans . Baby food s hav e als o been shown t o hav e high

er leadcontent s becaus e o f th e preservative s used . Th e origi n o

f leadi n ra w foo dstock s i s stil l amatte r o f som e controversy , althoug hpar t o f i t i s likel y t o b e th e consequenc e o

f man' s activitie s whichresul t i n makin g leadavailabl e fo r uptake b

y animal s an d plants . Suc

hredistributio n an dsubsequent uptake o f leadb y plant s i s well illustrate db y fivefoldincrease s i n th e amount

o f lea dpresen t i n tre e ring s over

a50

- yea r period . I t i s importan t

t o realiz e that

huma n exposur e an d intak e ar e no t

limite dt o th e primary source s of lead i n th e environmen t

but , rather , t o th e su

mo f prim

ary , secondary , an dtertiar y sources . Tabl e 13- 1 dis

play s thes e sources . TABLE 13-1 . SOURCE S O F LEAD FO RHUMAN EXPOSURE S Primary exposur e sourc e Ai r

Pain t Wate rfro m leade d pipe s Foo d

a Reentrainmen t Secondar y exposur e sourc e Dus t an d soi l Wate r Dus t an d soi l Tertiar y exposur e sourc e Foo d Runof f wate r Air a Runof f wate r Air a



### 13.2. 2 Route s an

d Mechanisms of

Entr y Chapte r 1 0 present s dat aon th e entry of leadint o th e huma n body . Tw o route s o

f entr y are o f principa l importance, inhalatio n andingestion . Intak e o f air

born e lea di s governe db

y th e physica

l an dchemical state o f inhale dlead , particl e siz e retentio n i n th e lung , andabsorptio n fro mth e lun g int o th e re d bloo dcells . Th e secon dmajo

r rout e o f entr y i s ingestion , bot

h o f foodando

f nonfoo dmaterial . Uptake i s con trolle db y th e nutrien t

balanc e o

f th e foodingested , particularl y that

o f iron , b y th e physica

l natur e o

f th e lead-bearin g materia l ingested , an db y th e chemical compositio n o

f th e substance . Here , too , th e leadi s absorbe db

y circulatin g re dbloo dcells . Th e tota l interna l dos e o

f leadwhichconfront s th e orga n system s o

f th e bod y i s th e su

mo f th e leadin

tak e b y bothroute s o

f entry : inhalatio n an dinges

tion . Thu s th e tota l interna l dos e represent s th e sum matio n o f al l externa l source s t o whichth e body i s exposed . Som

e o f thes e exposure s ma

y b e o f different relativ e significanc e i

n divers e populatio n group s du e t o variance s i n metabolis mo r

behavio r amon g different

segment s of

th e population . 13. 3 EVIDENC E O F INCREASE D BLOO D LEA D LEVEL S IN HUMAN S EXPOSE D T O ENVIRONMENTA L LEA D 13.3. 1 Relationship s Between Bloo d Lea d Level s an d Single-Source Exposure s Researc hha s been conducte don al l si x major ex posur e source s —air , dust , soil , water , paint , an d food . Chapte r

1 2 provide dth e detaile ddescription , evaluation , an dfinding s o f thos e studies . No t

al l source s hav e been studie dwit hth e same intensity , 13- 2P.5 5

an dfoo dha s bee n studie dleast . I n addition , foo da s atertiar y exposur e sourc e i s difficul t t o evaluate . Lea dconten t

i n foo ddu e t o packagin g an dprocess in g ha s bee n studie dmor e thoroughl y tha n contribu

tio n fro mtha t

lea dpresen t

at th e poin t

o f origin . Single-sourc e studie s o f ai r hav e include dbot h epidemiologica l an dclinica l investigations . Clinica l dat auniforml y demonstrat e th e actua l uptak e o f air

born e lea dint o blood , an depidemiologi c dat aals o generall y suppor t

suc harelationship . Studie s concerne dwithdus t an dsoi l lea dex posure s will b e considere dtogethe r sinc e in man y studie s th e investigator s di dno t attemp t t o dea l with thes e source s separately . Considerabl e evidenc e ex ist s tha t thes e exposure s ca n b e significan t determi

nant s o f bloo dlea dlevels . Furthermore , investiga

tion s o f childre n expose dt o lead-contaminate ddus t hav e demonstrate dmor e lea do n th e children' s hands , thu s documentin g aplausibl e rout e o f entr y whic hi s du e t o norma l ora l behavio r i n youn g children . I t

ma y b e wort hreiteratin g her e tha t th e dos e o f lea dingeste dfro mdus t an dsoi l appear s t o b e additiv e t o tha t

inhale dfro mair . Th e popula r

assumptio n tha t

lead-base dpain t

i s th e singl e causativ e agen t o f elevate dbloo dlea d level s in childre n ha s resulte di n limitin g th e defini

tio n o f high-ris k

childre n t o thos e residin g in olde r housing . A s aresult , lea dscreenin g program s hav e bee n establishe dwithth e sol e purpos e o f identifyin g childre n withelevate dlea dlevel s amon g thos e liv

in g i n ol dhousing . Abatemen t effort s hav e fre

quentl y bee n unabl e t o fin dlea dpain t source s fo r childre n withhig hbloo dlevel s foun db y suc h screenin g programs . Th e possibl e contributor y rol e o f airborn e lea dt o th e lea dburde n o f urba n childre n ha s unti l recentl y receive dlittl e attention . Finally , studie s fro mGlasgo w an dBosto n hav e show n elevate dbloo dlea dlevel s i n conjunctio n wit helevate dlevel s o f

lea din th e drinkin g water . Secondar y effect s o f

occupationa l exposur e hav e bee n examine di n childre n whos e parent s wor k in lea dindustries . I t

ha s bee n foun dtha t

parent s carr y hom e lead-contaminate ddust . Significan t relation

ship s betwee n hous e dus t level s an dbloo dlea d level s hav e invariabl y bee n establishe din thes e studies . 13.3. 2 Multiple-Sourc e Exposure s Studie s measurin g th e quantit y o f lea di n multipl e sources , aroun dprimar y lea dsmelter s o r in urba n settings , hav e consistentl y demonstrate da n additiv e relationshi p betwee n bloo dlea dlevel s an dexposur e t o th e severa l source s studied . 13.3. 3 Effec to f Hos tFactor s o n Bloo d Lea d Level s Hos t characteristic s tha t

mediat e th e relationshi p betwee n exposur e t o lea dan dbloo dlea dleve l hav e bee n examine din severa l studies . I n particular , ag e ha s bee n show n t o b e asignifican t facto r in deter

minin g bloo dlea dlevels ; thi s relationshi p i s dis

cusse dbelo w in mor e detai l i n th e sectio n (13.6 ) o n population s at

greates t risk . Se x difference s hav e bee n foun dt o b e ag e related . Particularl y amon g preschoo l boy s an dgirls , vir

tuall y n o differenc e ha s bee n established . I n th e adul t population , however , male s generall y exhibi t highe r level s tha n females . Dat ao n th e racial/ethni c facto r ar e sparse . On e stud y ha s reported.tha t blac k childre n hav e highe r lea dlevel s tha n d o whit e children . Althoug hth e sig

nificanc e o f

th e racial/ethni c facto r canno t b e estab

lishe da t thi s time , i

t seem s reasonabl e t o assum e tha t it i s th e socioeconomi c rathe r tha n th e geneti c dimensio n o f

thi s variabl e tha t

ma y prov e t o b e rele

vant . Socioeconomi c variable s suc ha s incom e an d educatio n hav e no t

bee n examine dadequatel y a s in

dependen t

factors . Associate dcharacteristic s suc ha s residenc e in ol dhousing , o r proximit y t o high-den

sity traffi c arterie s o r

t o stationar y source s suc ha s smelters , hav e bee n show n t o b e directl y relevant . I n epidemiologica l studie s th e healt hstatu s a s a variabl e ha s no t

bee n examined . Condition s suc ha s iro n deficienc y anemia , othe r state s o f malnutrition , sickl e cel l anemia , an dlactos e intoleranc e a s hos t factor s i n lea dintak e an ddeterminant s o f physiologica l an dpathologica l change s hav e onl y recentl y com e unde r

study . N o finding s ar e availabl e a s yet . 13.3. 4 Summar y o f

th e Quantitativ e Relationshi p Statistica l evaluatio n o f th e dat acollecte dfro m populatio n an dclinica l studie s ha s bee n presente din th e previou s chapter . Ther e it wa s note dtha t

th e weigh t o f th e evidenc e indicate s tha t bloo dlea d level s follo w alognorma l distributio n i n expose d population s wit hageometri c standar ddeviatio n o f 1. 3 t o 1.5 . I t

wa s als o see n tha t

th e lognorma l distri

butio n ha s propertie s tha t mak e it amenabl e t o us e i n th e standard-settin g process , sinc e i t permit s a n esti

mat e o f th e proportio n o f

th e populatio n whos e bloo dlea dlevel s excee dan y specifie dlevel . Detaile dexaminatio n o f th e clinica l an d epidemiologica l studie s relatin g ai r lea dlevel s t o bloo dlea dlevel s i s presente di n Chapte r 12 . Evi

denc e indicate s tha t

apositiv e relationshi p exist s be

13- 3P.5 6

twee n bloo dan dai r

lea dlevels , althoug hth e exac t functiona l relationshi p ha s no t yet bee n clarified . Availabl e dat aindicat e tha t i n th e rang e o f

ai r lea d exposure s generall y encountere db y th e population , th e rati o o f

th e increas e in bloo dlea dpe r uni t o f ai r lea di s fro m1 t o 2 . I t appear s tha t

th e rati o fo r childre n i s i n th e uppe r en do f th e rang e an dtha t ratio s fo r

male s ma y b e highe r tha n thos e fo r females . Quantitativ e relationship s ca n als o b e establishe d betwee n bloo dlea dlevel s an dexposur e t o lea din soil . Ther e i s genera l agreemen t tha t bloo dlea d level s begi n t o increas e a t soi l lea dlevel s o f

fro m 50 0 t o 100 0 ppm . Mea n percen t increase s i n bloo d lea dlevels , give n atwofol dincreas e i n soi l lea d levels , range dfro m3 t o 6 . Thi s i s aremarkabl e con sistency , give n th e divergenc e o f th e population s studied . 13. 4 AVERAGING-TIM E CONSIDERATION S On e o f th e majo r

area s o f concer n i n dealin g with quantitatio n o f

th e relationshi p betwee n ahealt h effec t an da n externa l dos e o f som e environmenta l pollutan t i s th e determinatio n o f ho w lon g a n ex posur e mus t

occu r befor e ther e i s a n effect . Evidenc e presente di n Chapte r 1 2 indicate s tha t

a 5 figldl increas e in bloo dlea dca n resul t fro ma n ai r lea dexposur e o f

3. 2 /ug/m 3 fo r

aperio do f

7 weeks . Furthermore , FE P level s hav e bee n show n t o in

creas e withi n 2 week s o f a n increas e o f

bloo dlea d levels . Therefore , an ai r lea dexposur e o f

3. 2 figlm 3 lastin g abou t

1 t o 2 month s ca n definitel y increas e th e bloo dlea dlevel . 13. 5 BIOLOGICA L AN D ADVERS E HEALT H EFFECT S O F LEA D I N MA N Lea ddoe s no t

presentl y hav e associate dwit hi t an y biologica l effec t

i n ma n whic hca n b e considere d beneficial ; therefore , an y consideratio n o f th e healt h effect s o f lea di n ma n mus t

b e don e fro mapoin t

o f vie w tha t acknowledge s th e absenc e o f an y healt h benefit/healt hcos t

ratio . A n additiona l an dextremel y importan t aspec t o f lead' s effec t

o n healt himpairmen t

tha t mus t b e con sidere di n ris k

assessmen t

i s th e questio n o f

whethe r thes e effect s ar e reversibl e onc e present . Physiologica l damag e t o centra l nervou s syste m tissu e i s presentl y widel y accepte da s bein g irreversi

ble ; thu s preventio n o f

lea dexposur e i s mos t

urgen t whe n on e consider s sever e neurologica l effects . Irreversibilit y i s als o accepte di n th e cas e o f rena l tissu e damag e resultin g fro mchroni c lea dexposure , particularl y i n case s wher e thes e effect s ar e manifeste dmorphologically . W e spea k o f physiologica l irreversibilit y i n th e case s o f neurologica l o r

rena l tissues , bu t

th e con cep t o f irreversibilit y o f

a n effec t

bein g likel y o r assure db y nonbiologica l factor s suc ha s continuing , long-ter mexposur e t o airborn e lea dmus t als o b e considered . Hematologica l effect s ar e o f relevanc e here . Althoug hanumbe r o f thes e hematologica l effect s ma y b e biochemicall y reversible , i f th e prob

abilit y o f

th e perso n bein g remove dfro mth e ex posur e settin g inducin g thes e effect s i s sligh t o r non existent , fo r

whateve r

reason , the n defacto irrever

sibilit y exists . Thi s sectio n summarize s th e biologica l effect s o f lea do n ma n wit hparticula r referenc e t o significanc e o f thes e effect s fo r

huma n health . Muc ho f th e atten tio n in thi s sectio n will b e directe dt o thos e biologi

ca l effect s whic hma y collectivel y b e terme d "subclinical. " B y definition , subclinica l effect s ar e disruption s i n function , whic hma y b e demonstrate d b y specia l testin g bu t

no t b y th e classi c technique s o f physica l examination ; usin g th e ter m"subclinical " in n o wa y implie s tha t

thos e effect s ar e withou t con sequence s t o huma n health . 13.5. 1 Assessmen to f

Hematologica l Effect s o f Lea d A multiplicit y o f

effect s o f

lea do n th e hematopoieti c syste mexists . Thes e effect s wer e dis

cusse di n detai l in Chapte r 11 , Sectio n 3 , an dar e briefl y summarize dhere . 13.5.1. 1 ANEMI A Anemi ai s aclassi c manifestatio n o f clinica l lea d intoxication , ofte n occurrin g prio r t o neurologica l an dothe r

syste mimpairment . Th e mechanis mo f anemi ai n lea dexposur e apparentl y involve s bot h decrease dproductio n o f hemoglobi n an denhance d destructio n o f

erythrocytes . Report s o n childre n in

dicat e tha t

statisticall y significan t decrease s i n hemoglobi n level s begi n t o appea r a t abloo dlea d leve l o f 4 0 figldl o r somewha t

below . I n adult s asig

nifican t decreas e i n hemoglobi n leve l appear s t o becom e eviden t

a t abloo dlea dleve l o f

5 0 figldl. 13.5.1. 2 LEA D EFFECT S O N HEM E SYN

THESI S A larg e numbe r

o f studie s hav e bee n don e o n th e effect s o f lea do n hem e synthesi s i n humans . Lea d interfere s wit hhem e synthesi s at severa l point s alon g th e heme-biosyntheti c pathway . Th e tw o mos t im

portan t point s o f

interferenc e are : (1 ) th e con densatio n o f

tw o unit s o f

8-aminolevulini c aci d dehydratas e t o formporphobilinoge n an d(2 ) th e in

13- 4sertio n o f iro n int o protoporphyri n I X whic hi s catalyze db y th e enzym e ferrochelatase . 13.5.1. 3 EFFEC T O FLEA D O N 8-AMINO

LEVULINAT E DEHYDRATAS E (8-ALAD ) AN D 8-AMINOLEVULINI C ACI D (8-ALA ) EX

CRETIO N A numbe r

o f studie s hav e show n th e hig hsen sitivit y o f 8-ALA D t o lea dan dth e negativ e correla

tio n betwee n bloo dlea dan dth e logarith mo f 8

- ALA D activity . Thes e studie s ar e describe din Sec

tio n 11.3 . I t

appear s tha t

thi s relationshi p hold s tru e fo r industria l workers , th e genera l population , an d children . Th e dose-respons e relationshi p betwee n bloo d lea dan dth e logarith mo f ALA D activit y appear s t o b e linea r

coefficien t

o f correlatio n (r ) = 0.84 . ALA D inhibitio n i s firs t note da t whol e bloo dlevel s o f 1 0 t o 2 0 figldl

(Chapte r

11) . Thi s hig hdegre e o f sensitivit y make s applicatio n an dinterpretatio n o f th e tes t difficult . ALA D inhibitio n i s virtuall y com plet e a t bloo dlea dlevel s o f

7 0 t o 9 0 figldl. Dat asummarize db y Hernberg 3 sugges t tha t hem e biosynthesi s i s no t

decrease db y ALA D inhibitio n unti l activit y o f

th e enzym e ha s falle n t o les s tha n 2 0 t o 3 0 percen t

o f normal . I n additio n t o it s effec t o n re dbloo dcel l ALAD , lea dappear s t o inhibi t ALA D activit y i n liver . I t ha s als o bee n suggeste d tha t in youn g childre n lea dmay inhibi t activit y o f ALA D in brain . 13.5.1. 4 EFFEC T O FLEA D O N IRO N INSER

TIO N INT O PROTOPORPHYRI N Accumulatio n o f

protoporphyri n in erythrocyte s in lea dexposur e i s th e resul t o f lead-induce dinhibi

tio n o f th e intramitochondria l enzyme , ferro

chelatase . Th e inhibitor y effec t o f lea do n fer

rochelatas e ma y eithe r

b e direc t

o r ma y b e mediate d b y adisruptio n in th e functio n o f mitochondria l membranes . Th e effec t

o f lea do n th e formatio n o f hem e i s no t limite dt o th e hematopoieti c system . Experimenta l anima l studie s hav e show n alea deffec t o n th e heme

requirin g protein , cytochrom e P-450 , a n integra l par t o f th e hepati c mixed-functio n oxidas e (Chapte r 11) , th e systemi c functio n o f whic hi s detoxificatio n o f exogenou s substances . Hem e synthesi s inhibitio n als o take s plac e i n neura l tissue . Th e elevatio n o f

fre e erythrocyt e protoporphyri n (FEP ) ha s bee n show n b y alarg e numbe r o f studie s t o b e exponentiall y correlate dwithbloo dlea dleve l in childre n an dadults . Presen t informatio n show s tha t a t relativel y fixe d bloo dlea dvalue s childre n an dprobabl y wome n

hav e highe r

protoporphyri n level s in thei r bloo d tha n adul t

males . Th e exac t

reaso n fo r

thi s i s no t known , bu t

it ma y b e o f

endocrinologica l origin . Elevatio n in protoporphyri n i s considere dno t onl y t o b e abiologica l indicato r o f impaire d mitochondria l functio n o f erythroi dtissu e bu t

als o a n indicato r

o f accumulatio n o f

substrat e fo r

th e enzym e ferrochelatase . I t therefor e ha s th e sam e pathophysiologica l meanin g a s increase durinar y 8

- AL A (vide supra). Fo r

thes e reason s accumulatio n o f protoporphyri n ha s bee n take n t o indicat e physiologica l impairmen t in humans , an dthi s clini

ca l concensu s i s expresse di n th e 197 5 Statemen t o f th e Cente r

fo r Diseas e Contro l (CDC) , USPHS . Th e criterio n use db y CD C t o indicat e a n effec t o f lea d o n hem e functio n i s an FE P leve l o f 6 0 /xg/d l i n th e presenc e o f

abloo dlea dleve l abov e 3 0 figldl whol e blood . Mor e recen t

informatio n relatin g t o threshol do f lea deffect s indicate s tha t FE P level s begi n t o in

creas e at abloo dlea dvalu e o f 1 5 t o 2 0 fig Pb/d l bloo din childre n an dwome n and , at asomewha t highe r value , 2 0 t o 2 5 fig Pb/ d1 blood , in adul t men . 13.5.1. 5 OTHE REFFECT S O N HEM E SYN

THESI S Ther e ar e othe r

abnormalitie s o f

hem e synthesi s tha t ar e aresul t

o f lea dexposure . Fo r

example , it

i s wel l know n tha t

a n increase durinar y copro porphyri n leve l i s foun di n lea dpoisone dchildre n an dlea dworkers . I t

i s no t know n whethe r

thi s effec t result s fro mspecifi c enzym e inhibition , fro m upstrea maccumulatio n o f substrat e secondar y t o th e inhibitio n o f

iro n insertio n int o protoporphyrin , o r fro madisturbanc e o f coproporphyri n transpor t throug hth e mitochondria l membrane . A n increase dactivit y o f 8-AL A synthetas e i s see n i n lea dintoxication , bu t thi s chang e probabl y arise s a s anegativ e feedbac k

contro l t o 8-AL A respons e t o inhibitio n upstrea mi n th e heme-biosyntheti c path

way . Fe w dat aexis t

t o quantitat e th e healt hsignifi

canc e o f thi s effect . 13.5.1. 6 EFFECT S O FLEA D O N GLOBI N SYN ^ THESE S Hemoglobi n synthesi s ma y als o b e impaire db y th e inhibitio n b y lea do f

globi n biosynthesis . Globi n i s th e protei n moiet y o f

hemoglobin . On e recen t stud y show s a n effec t

o n globi n synthesi s in vitro o n huma n reticulocyte s a t

lea dconcentration s correspondin g t o abloo dlea dleve l o f 2 0 figldl. 13- 5P.5 8



### 13.5. 2 Assessmen t

of Neurobehaviora l Effect s o f Lea d A s reviewe di

n Chapte r 11 , a n extensiv e literatur e document s th e advers e effects o f leado n th e centra l an dperiphera l nervou s system s o f man y huma n and nonhuman mammalian species . Only limite ddose

respons e dat aexis t

that migh t allo w externa l lea

d exposure parameter s t o b e linke ddirectl y t o th e oc currenc e o

f particular

neurobehaviora l effects . I n contrast , more dat aexis t

relatin g bloo dleadlevel s t o neurobehaviora l deficits ; major emphasi s her e i s therefore focusedon th e concis e summarizatio n o f relationship s between huma n bloo dlea

dlevel s an d neurobehaviora l effects . 13.5.2. 1 CENTRA LNERVOU S SYSTE M EFFECT S Amon g th e mos t

profoundl y deleteriou s effects o f leadpoisonin g ar e thos e associate dwit hsevere CN S damag e tha t

occur a t toxi c hig hexposure levels . Th e acut e overt

manifestation s o

f neura l damag e at

high lea dexposur e level s includ e suc hsymptom s a s ir

ritability , stupor , convulsions , and/o r coma , which characteriz e th e well-know n encephalopath y syn drome . Suchsymptom s a

t time s occur

abruptl y dur

in g th e cours e o

f muchmilde r

symptomatolog y o r eve n i n apparentl y asymptomati c lea dpoisone din

dividual s an dma

y progres s t o deat

hwithin 4 8 hr . Even i n th e absenc e o

f deat hor prolonge duncon sciousness , i

t i s no w widely accepte dthat

irreversi

bl e neura l damag e typicall y occur s a s on e o f th e se quela e o f nonfatal lea dencephalopath y episodes . Suc hpermanen t

neural damag e i s reflecte db y sign s o f continuin g CN S impairmen t rangin g fro

msubtl e neurobehaviora l deficit s t o severe menta l retarda

tio n o r continuin g mental incompetence . Wha t i s no t ye t universall y agree dupon , however , ar e th e lea d level s sufficien

t t o produc e leadencephalopath y an d it s sequelae . I n regardt o th e issue o

f threshol dlevel s fo

r lea d encephalopathy , bloo dleadlevel s o f 12 0 figldl o r more ar e currentl y widely accepte da s necessar y t o produc e encephalopath y symptom s i n adults . Th e publishe devidenc e bearin g on thi s point , however , i s ver y limited . Include damon g suc hevidenc e ar e a fe w scattere dreport s suggestin g tha t acut e en cephalopath y o r

deat hma y occur i n adult s a t bloo d lea dlevel s unde r

10 0 figldl (from8 0 t o 100 figldl), but th e rarity o

f suchcase s an dambiguitie s i n th e re porte ddat arende r

i t difficult t o accep t thos e report s a s evidenc e fo

r encephalopath y i

n adult s a

t bloo d lea dlevel s belo w 120 figldl. Muchbette r

evidenc e exist s fo

r th e occurrenc e o

f lea dencephalopath y i

n childre n a

t bloo dleadlevel s belo w 120figldl

o r even 100/xg/dl . Tha t

is , i t i s well documente dthat

suchsymptom s occur

fo r some childre n beginnin g at

th e 100 figldl

level ; also , several scattere dreport s sugges t that somewha

t lowe r threshol dlevel s ma

y obtain , i.e. , i

n th e 8 0 t o 10 0 figldl range , althoug hsuchreport s mus t b e viewedwit

hcautio n a s i

n th e cas e fo

r analogou s result s fo r adults . A s indicate dearlier , th e issue o f whether ap parentl y asymptomati c childre n experienc e subtl e neurobehaviora l deficit s a t low-to-moderat e bloo d lea dlevel s i n th e 4 0 t o 8 0 /xg/d

l rang e remain s asub

jec t o f muchcontroversy . A thorough , critica l revie w o f

th e relevan t

literatur e presente di n Chapte r 11 , nevertheless , lead s t o th e conclusio n that bloo dlea

dlevel s o

f 5 0 t o 6 0 figldl

ar e likel y sufficien t t o caus e significant

neurobehaviora l im

pairment s fo

r at leas t som e apparentl y asymptomati c children . Th e impairment s consis t mainly o f cogni

tiv e or sensory-moto r

integratio n deficits , bu t d o not appea r t o includ e th e occurrenc e o f hyper

activity ; tha t

latte r effec t seem s t o b e muc

hbette r es tablishe da s on e o

f th e neurological sequela e follow

ing encephalopath y at

higher leadlevels . 13.5.2. 2 PERIPHERA L NEUROPATH Y EFFECT S In additio n t o th e abov e CN S effects , periphera l nervou s syste

mdamag e als o result s fro mexposure s t o lead . Suc

heffects hav e been bes t

documente da s occurrin g afte

r long , chronic , high-leve l exposure s i n adult s exhibitin g othe r

symptom s o

f leadintoxica

tion . Recent

studie s o

f apparentl y asymptomati c adults , usuall y occupationall y expose dt o lead , however , presen t

reasonabl y stron g evidenc e forperiphera l neuropath y a

t more moderat e leadex posure levels , i.e. , at

bloo dleadlevel s i

n th e rang e o f 5 0 t o 7 0 figldl. Periphera l neuropath y effect s ar e typicall y associate dwit

hadul t exposures , havin g been reporte dmuc

hles s frequentl y fo

r children . A fe w report s o

f lead-induce dperiphera l neuropathie s i n children , however , contai n evidenc e fo r th e oc currence , i

n som e rar e instances , a

t bloo dleadlevel s a s low a s 5 0 t o 6 0 figldl. 13.5.2. 3 RESULT S O FANIMA L STUDIE S AS SUPPORTIV E EVIDENC E Revie w o f th e literatur e o

n th e neurobehaviora l effects o f lea di n animal s provide s evidenc e suppor tiv e o f th e abov e conclusion s fro mhuma n studies . That is , ther e appear s t o b e adifferential sensitivit y o f newbor n o r youn g animal s o

f man y specie s t o th e neurobehaviora l effects o

f lead . Thi s applie s bot

h t o 13- 6P.5 9

th e inductio n o f

lea dencephalopath y a t hig hex posur e level s an dmor e subtl e neurobehaviora l deficit s a t

lower , mor e moderat e exposur e levels . I n regar dt o specifi c type s o f subtl e neurobehaviora l effects , hyperactivit y appear s t o occu r mainl y a t bloo dlea dlevel s i

n exces s o f

7 0 t o 8 0 figldl

and , therefore , probabl y mos t closel y parallel s th e pos t encephalopathi c hyperactivit y wel l demonstrate da s on e o f th e sequela e o f

lea dencephalopath y i n humans . Othe r

behaviora l changes , interprete da s indicativ e o f

cognitiv e impairment s resultin g fro m CN S effects , appea r

t o occu r

in animal s a t

bloo d lea dlevel s belo w thos e associate dwit hacut e en cephalopathi c effects , i.e. , in th e 3 0 t o 8 0 /xg/d l bloo dlea dleve l range . Thi s parallel s rathe r closel y th e effect s observe dfo r

humans , especiall y children , excep t tha t cognitiv e deficit s hav e no t bee n ver y wel l documente din th e childre n at level s belo w 5 0 t o 6 0 figldl. Th e externa l lea dexposure s yieldin g th e abov e result s fo r

animals , however , typicall y appea r t o b e muc hhighe r

tha n thos e producin g comparabl e effect s i n humans ; th e comparabilit y o f anima l studie s an dhuma n studie s i s therefor e ofte n ques tioned . I f

on e focuse s o n th e resultin g bloo dlea d level s achieved , regardles s o f associate dexterna l dose , however , th e result s o f th e anima l studie s paralle l thos e o f

th e huma n studie s remarkabl y well . I n discussin g th e neurobehaviora l effect s o f lead , abov e in th e presen t

sectio n an di

n Chapte r

11 , adis

tinctio n ha s repeatedl y bee n mad e betwee n thresh

ol dlevel s yieldin g sever e symptom s o f lea d encephalopath y see n at hig hexposur e level s an d mor e subtl e neurobehaviora l deficit s observe dat lowe r exposur e levels . Thi s approac hma y inappro

priatel y conve y a n impressio n o f suc heffect s occur rin g in adiscrete , step-lik e fashio n a s particula r threshol dbloo dlea dlevel s ar e reached . I t i s impor

tan t t o not e tha t

thi s ma y occu r

insofar a s shiftin g fro mapparen t

no-effec t

level s t o level s a t

whic h fairl y wel l substantiate dneurobehaviora l effect s hav e bee n foun dt o occur , i.e. , aroun d5 0 t o 6 0 figldl; beyon dtha t

point , however , furthe r increase s in relativ e level s o f

neura l damage , a s indicate db y increasingl y sever e neurologica l o r behaviora l deficits , occu r

i n amor e o r

les s smoothl y ascendin g fashio n in relatio n t o increasin g bloo dlea dlevels . Thes e relationship s ar e presente dlate r i n a n approximat e manne r

i n Tabl e 13-2 . Du e t o difference s i n individua l susceptibility , it shoul db e emphasize dtha t

th e uppe r

en do f th e rang e o f

bloo d lea dlevel s a t

whic hsubtl e neurobehaviora l effect s hav e bee n reporte dt o occu r fo r som e individual s merge s o r

overlap s substantiall y wit hth e lowe r en d o f

th e rang e a t

whic hmuc hmor e sever e en cephalopathi c symptom s hav e bee n observed , an d tha t th e shif t fro msubtl e t o sever e neura l symptom s may b e quit e abrupt . 13.5. 3 Effect s o f

Lea d o n Reproductio n an d Developmen t Althoug hth e effect s o f lea dexposur e in human s hav e usuall y bee n associate dwit hth e hematopoietic , neural , an drena l systems , concer n need s t o b e equall y directe dt o th e entir e are ao f reproductio n an ddevelopment , wit hspecia l emphasi s o n th e vulnerabilit y o f

pregnan t

wome n or , mor e ac curately , th e vulnerabilit y o f th e fetus . Attentio n in thi s are ai s focuse do n tw o aspect s o f reproduction : (1 ) th e gametotoxi c effect s o f lead , i.e. , lea deffect s o n spermatogenesi s an dovaria n function , an d(2 ) postconceptio n event s throug h delivery . 13.5.3. 1 HUMA N GAMETOTOXICIT Y Som e dat ainvolvin g effect s o f lea dexposur e o n th e fertilit y o f

male s exist , an dthes e hav e bee n ob

serve da t bloo dlea dlevel s o f

5 0 t o 8 0 /xg/d l unde r condition s o f

occupationa l exposure . Wit hregar dt o women , on e stud y o n lea deffect s (se e Reproductio n an dDevelopmen t

section , Chapte r

11 ) raise s th e possibilit y tha t

th e ovaria n cycl e ma y b e disturbe din th e ag e rang e o f

2 0 t o 2 5 year s withai r lea dlevel s aroun d7 /xg/m 3

. 13.5.3. 2 POSTCONCEPTIO N LEA D EFFECT S Bot hearl y literatur e an dmor e curren t studie s conclusivel y sho w tha t lea dcrosse s th e placenta l barrier . Suc hfeta l exposur e therefor e commence s a t abou t th e en do f

th e firs t trimeste r

(1 2 weeks ) an d continue s throughou t

feta l development . A s ha s alread y bee n pointe dout , th e distributio n o f lea d withi n th e fetu s a t

differen t stage s o f

developmen t

i s probabl y mor e importan t tha n th e tota l amoun t

pre sen t a t birth . Tissu e analysi s als o demonstrate s that , i n Ameri

can s fro mnewborn s throug hperson s age d1 9 years , brai n lea dlevel s appea r t o b e mos t

elevate da t

birt h an dthe n diminis hwit hdevelopment . A numbe r

o f studie s sho w passag e o f lea dthroug h th e placenta l barrie r

b y comparin g cor dbloo dlea d an dmaterna l bloo dlea dlevels . Thes e studie s furthe r serv e t o she dsom e ligh t o n th e effec t

o f variou s factor s i n infan t bloo dlea dvalues . I n agrou p o f

cor dblood/materna l bloo dmatch

ings , infan t

bloo dlevel s wer e highl y correlate dwit h thos e o f thei r mothers . A secon dstud y showe dtha t 13- 7P.6 0



### bloo dvalue s fo

r infant s whos e mother s wer e urban resident s were significantly higher than thos e o

f rura l infants . A study don e i

n alead-bel t

are ao f th e Unite d State s raise s th e possibilit y that leadma y affect th e cours e o f norma l delivery o

f childre n sinc e ther e wer e more incident s o

f pretermdeliver

y an dpre mature membran e ruptur e i n pregnan t

wome n i n thi s regio n compare dt o agrou p fro marelativel y unex pose darea . 13.5. 4 OtherHealt

h Effects 13.5.4. 1 RENA LEFFECT S Nephropath y i s aconditio n usuall y considere di n it s chroni c for

mandthat

ca n bes t b e relate dt o prolonge dexposure t o leadwit hacorrespondin g bloo dlea dleve l o f abou t 7 0 figldl. Becaus e chroni c leadnephropath y result s only afte r prolonge do r repeate dexposures , i

t i s impossibl e t o recapitulat e accuratel y th e exposure history ; therefore , deter

minatio n o

f a n exposure threshol dfo

r thi s conditio n i s impossible . 13.5.4. 2 EFFECT S O FLEA D O N TH E EN

DOCRINOLOGICAL , HEPATIC , CAR

DIOVASCULAR , AN D IMMUNOLOGICA L SYSTEM S Althoug hsom e studie s hav e bee n don e i n referenc e t o eac ho

f th e system s i

n thi s subsection , ther e exist s to o littl e quantitativ e informatio n relat

in g bloo dleadlevel s t o th e endocrinological , hepatic , an dcardiovascular systems . 13.5. 5 Does-Effect/Respons e Relationship s I n an y discussio n o

f th e ris k assessment

directe d towardaparticular

agent , suc

ha s lead , tw o ques tion s arise : 1 . Wha t ar e th e lowes t

level s o f th e interna l dos e (bloo dleadlevel ) that giv e ris e t o an

y biological effect ? 2 . Wha t dose-respons e relationship s ar e ob

taine dtha t

defin e aproportio n o

f apopu latio n manifestin g agiven biological effec t a t aparticular

interna l dose ? Informatio n summarize di n th e precedin g sectio n deal t wit hrelationship s between bloo dlea dlevel s an dvariou s biological effects o f lead . Many o

f th e dat adiscusse dabov e concerne dthreshol dlevel s a t whichhealt

heffects o

f leadar e firs t

observe di

n different populatio n groups . Tabl e 13- 2 summarize s th e threshol dlevel s a

t whichvariou s specifi c hematological an dneurobehaviora l effects hav e been observe dfo

r particular

subpopulations . A number

o f investigator s hav e attempte dt o quantitat e mor e precisel y lead' s dose-respons e relationship , i.e. , th e proportio n o f apopulatio n ex hibitin g healtheffects a

t agiven bloo dleadlevel . TABL E 13-2 . SUMMAR Y O F LOWES T OBSERVE D EFFEC TLEVEL S Lowes t observe d effec t leve l Populatio n grou p 1 0 15-2 0 25-3 0 4 0 4 0 4 0 5 0 50-6 0 50-6 0 80-10 0 100-12 0 ALA D inhibitio n Erythrocyt e protoporphyri n elevatio n Erythrocyt e protoporphyri n elevatio n Increase d urinar yAL Aexcretio n Anemi a Coproporphyri n elevatio n Anemi a Cognitiv e (CNS ) deficit s Periphera l neuropathie s Encephalopath ysymptom s Encephalopath ysymptom s Childre n an d adult s Wome n an d childre n Adul t male s Childre n an d adult s Childre n Adult s an d childre n Adult s Childre n Adult s an d childre n Childre n Adult s 

### Du e t o th e limite davailability o f data , mos t

suchat tempt s hav e been restricte dt o effects on th e hematologi c system , i

n particular

th e elevatio n o

f FEP , th e inhibitio n o

f ALA D activity , an dth e ex cretio n o f ALA i n th e urine . I n regar dt o definin g dose-respons e relationship s fo r hematological effects , thre e different assessment s o f suchrelationship s hav e been carrie dout 4 6 

### an d published . Fo r example , in th e approac hof Zielhuis, 4 

### dose-respons e relationship s wer e develope dfo

r ALAD , ALA-U , an dFE P a s obtain

e dfo r adults , mal e andfemale , an dchildren . I n Figure 13- 1 ar e presente dth e dose-respons e dat afo r childre n an dadult s fo

r ALA D a t inhibitio n level s o

f 4 0 an d7 0 percent . In Figur e 13-2 , acorrespondin g relationshi p fo

r urinary ALA i s given for adul t males , an dFigur e 13- 3 present s th e correspondin g 13- 8P.6 1

dat afo r FE P i n adul t

males , adul t

females , an d children .

z O S « 8 0 I - Q < U J

_ l H = 2 S S 6 0 "> •A u . . O I ; 4 0 — _

— 1 

### 1

x J 

### / / / / / / / / / / / / y 

### l - V 

### / / 1 —(^40 %

70 % / / / / / / / / / 1 1 

# " P

1 * - 1 >40 % >70 %

ADULT S CHILDRE N 1 —

.

_

- I f < O I 2 0

0 1 0 3 0 5 0 7 0 BLOO D LEA D LEVEL , u g Pb/d l Figur e 13-1 . Dose-respons e curv e fo r percen t ALA D inhibi tio n fo r adult s an d childre n a s a functio n o f bloo d lea d level .

° - < 6 0 O w u u A > 5 mg/lite r

mg/lite r

3 0 5 0 BLOO D LEA D LEVEL , u g Pb/d l Figur e 13-2 . Dose-respons e curv e fo r ALA i n urin e (ALA-U ) a s a functio n o

f bloo d lea d level. 4 A s ca n b e see n fro mFigur e 13-1 , ther e appear s t o b e amarke ddifferenc e a t 4 0 percen t

inhibitio n o f ALA D activit y betwee n childre n an dadults , suc ha differenc e decreasin g a s on e goe s t o 7 0 percen t in

hibition . Fo r

example , a t

2 0 /xg/d l bloo dlead , ap proximatel y 1 0 percen t o f adult s sho w 4 0 percen t enzym e inhibition , wherea s th e correspondin g valu e fo r childre n i s somewha t

abov e 8 0 percent . I t

shoul d als o b e note dtha t

ther e i s apparentl y astee p ris e in th e linea r

portio n o f

thes e sigmoi drelationships , e.g. , 2 0 percen t

o f adult s sho w a4 0 percen t inhibi

tio n i n ALA D a t

2 0 figldl bloo dlead , wherea s vir

tuall y al l o f

th e adul t

populatio n show s 4 0 percen t inhibitio n a t

4 0 figldl. A simila r

steepnes s in th e curv e i s see n i n regar dt o children . Figur e 13- 2 present s dose-respons e dat afo r AL A i n urin e exceedin g tw o discret e levels , > 5 an d>1 0 mg/liter , wit hincreasin g bloo dlead . I t ma y b e see n tha t th e respons e i n th e linea r portio n o f

th e curv e i s muc hles s stee p tha n fo r ALAD . Fo r

example , fo r approximatel y 5 percen t o f adults , th e no-respons e leve l fo r AL A > 5 mg/lite r

i s abou t 3 0 figldl bloo d lead . A t 6 0 figldl bloo dlead , th e correspondin g per centag e o f

th e populatio n showin g thi s respons e i s i n exces s o f 8 0 percent . Th e correspondin g plo t fo r AL A > 1 0 mg/lite r

show s ales s stee p slop e tha n th e forme r case . A t

6 0 figldl

bloo dlead , th e corres pondin g percentag e o f

th e adul t

populatio n i s ap proximatel y 40 . Th e composit e dose-respons e plo t presente di n Figur e 13- 3 show s a n increase drespons e i n FE P i n adul t female s compare dt o adul t males . Childre n sho w agreate r

respons e tha n adul t

male s onl y u p t o bloo dlea dlevel s o f

abou t 4 5 /ug/dl . Th e dat ao f Zielhui s ar e extracte dfro manumbe r o f reports . I n Figur e 13-4 , interestingly , wherei n ar e containe dth e

o A < » 10 0

8 0

6 0

4 0

2 0 -

- 1 1 1 1

ADUL TFEMALE S /* "

1 /l*""' l 1 1 1 1

/ADUL TMALE S

1 / CHILDRE N

1 1 1 -

-

-

-

-

3 0 5 0 BLOO D LEA D LEVEL , u g Pb/d l Figur e 13-3 . Dose-respons e curv e fo r FE P a s a functio n o f bloo d lea d level. 4

Q U J K < (/ > A

ADUL TMALE S

2 0 3 0 BLOO D LEA D LEVEL , u g Pb/d l Figur e 13-4 . Dose-respons e curv e fo r FE P a s a functio n o f bloo d lea d level. 5 13- 9.P.62 _

dose-respons e dat ao f

Roel s e t al. 5 fo r FE P i n adul t males , adul t

females , an dchildren , it appear s tha t childre n sho w th e mos t heightene dresponse , followe db y adul t

females , an dth e leas t

respons e i n adul t males . Th e slop e fo r

th e linea r

portio n o f

th e respons e curv e i s quit e stee p i n th e cas e o f children ; 2 0 percen t

o f th e childre n sho w elevate drespons e (8 2 /xg/d l rbc ) a t

2 0 /ug/d l bloo dlead , wherea s vir

tuall y al l th e childre n excee dthi s valu e a t 3 5 /ug/d l bloo dlead . Th e dose-respons e dat ao f Piomelli 6 ar e presente d i n Figur e 13- 5 an dconsis t o f composit e plot s fo r mea n plu s 1 standar ddeviatio n (3 3 figldl whol e blood ) an dth e mea n plu s 2 standar ddeviation s (5 1 fig FEP/d l whol e blood) . I n th e dat apresente di n Figur e 13-5 . bloo dlea dlevel s in exces s o f 2 8 figldl whol e bloo dwer e no t

use di n tn e calculations . I t ap pear s fro mth e abov e tha t ther e exist s athreshol da t abou t 1 5 figldl

whol e blood .

> 9 8 — Q 9 5 — 9 8 9 5 9 0 7 5 5 0 2 5

5 2 1 1 NOT E

1 1 1 1 1 1 1 1 POINT S OUTSID E TH E RANG E O F TH E SOLI D LINE S WER E NO TUSE D IN CALCULATION S

0 r > - s * — FE P > MEA N + 1 S.D . (3 3 ug/dl ) ' 

# j* y Jg rf

FEP>MEA N + 2 S.D .

_tm JT

j f

(5 1 ug/di ) 

# ? y* S QV J C (NATURA L FREQUENCY ) — 

### o ° /f^ ^ 1 " 1 I I I I 1 ? 2 5 - 

### ° ,„ _

### = < 5 -

0 1 0 2 0 3 0 4 0

BLOO D LEA D LEVEL , ug Pb/d l Figur e 13-5 . Dose-respons e curv e fo rFE P a s a functio n o f bloo d lea d level. 6 EP A ha s carrie dou t

analyse s o f

th e dat afro mth e Aza r e t al . study 7 an dcalculate dadose-respons e curv e fo r urinar y AL A (Figur e 13-6) . Thes e dose

respons e curve s wer e plotte dfo r tw o differen t

cut of f points . Thes e point s wer e th e mea n value s fo r bloo dlea dlevel s les s tha n 1 3 figl 100 g , plu s 1 stan dar ddeviatio n an dplu s 2 standar ddeviations , respectively . Fro mth e mea n plu s 2 standar ddevia

tion s curve , i t

i s readil y apparen t

tha t th e linea r

por tio n o f th e curv e i s quit e steep . A t abloo dlea dleve l o f 2 0 figldl, onl y 6 percen t o f th e populatio n excee d th e mea n plu s 2 standar ddeviation s valu e o f th e contro l population , wherea s a t abloo dlea dleve l o f 50 , 5 0 percen t

o f th e populatio n exceed s tha t value . Furthermore , whe n on e examine s th e figur e a t 4 0 figldl, th e valu e at whic hAL A in urin e i s take n t o sugges t healt himpairment , th e Aza r e t al . dat asho w tha t abou t 3 0 percen t

o f th e populatio n show s a n elevatio n i n thi s parameter .

4 8 0

< <s o s Z 5 0 o

MEAN + 1 S.D . MEA N + 2 S.D . MEA N ALA- U » 0.3 2 FO R BLOO D

LEA D < 1 3 ug/d l J I I I I I BLOO D LEA D LEVEL , u g Pb/d l Figur e 13-6 . EPA calculate d dose-respons e curv e fo r ALA- U (fro m Azare t al. 7 ) . I n Tabl e l 3- 3 ar e tabulate dproportion s o f th e stud y population s in th e Zielhui s an dAza r report s showin g elevate durinar y AL A versu s bloo dlea d level . Th e dat afo r

Zielhui s ar e a s cite di n Figur e 13-2 , th e percentag e o f

subject s wit hALA- U greate r tha n 5 mg/lite r

bein g used . Th e Aza r

dat ai n Tabl e 13- 3 refe r t o th e mea n plu s tw o standar ddeviation s dat aset . Fo r

purpose s o f

compariso n o f

dose

respons e dat afo r

FEP , th e studie s o f

Zielhuis, 4 Roels, 5 an dPiomelli 6 ar e tabulate din Tabl e 13-4 . A s i n th e cas e fo r

th e tabl e o f

ALA- U data , it

shoul d b e kep t i n min dtha t

difference s exis t

i n cut-of

f point s fo r

FE P respons e t o lea di n th e variou s studies . TABL E 13-3 . ESTIMATE D PERCENTAG E O F SUBJECT S WIT H ALA- U EXCEEDIN G S mg/lite rFO R VARIOU S BLOO D LEA D LEVEL S Bloo d lea d levels . ijg'd l 1 0 2 0 3 0 4 0 5 0 6 0 7 0 4 Zielhuis . % 0 0 6 2 4 4 8 7 6 9 6 Aza re t at. .

% 2 6 1 6 3 1 5 0 6 9 8 4 13-1 0TABL E 13-4 . ESTIMATE D PERCENTAG E O F CHILDRE N WIT H E P EXCEEDIN G CUT-OF F POINT S FO R VARIOU S

BLOO D LEA D LEVEL S Bloo d lea d level , ug/d l 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 Zielhuis a %

0 6 22 37 49 — —

—' Roel s e t al,. b % 3 2 7 7 3 10 0 — — — — Piomelli. c %

9 1 1 4 8 8 0 — — — —

a E P > E P o

f childre n wit h Pb- B < 2 0 iig/dl . b E P >8 2 ugd l cells . C E P >EPo l 33ug'dl . 13. 6 POPULATION S A T RIS K Populatio n a t

ris k i s asegmen t

o f adefine d populatio n exhibitin g characteristic s associate dwith significantl y highe r

probabilit y o f

developin g acon dition , illness , o r

othe r abnorma l status . Thi s hig h ris k ma y resul t

fro meithe r

greate r inheren t suscep tibilit y o r

fro mexposur e situation s peculia r t o tha t group . Wha t

i s mean t b y inheren t

susceptibilit y i s a hos t characteristi c o r

statu s tha t

predispose s th e hos t t o agreate r

ris k o f heightene drespons e t o an exter na l stimulu s o r

agent . I n regar dt o lead , tw o suc hpopulation s ar e definable . The y ar e preschoo l ag e children , especiall y thos e livin g in urba n settings , an dpreg nan t women , th e latte r

grou p owin g mainl y t o th e ris k t o th e conceptus . Childre n ar e suc hapopulatio n fo r bot ho f

th e reason s above , wherea s pregnan t wome n ar e a t

ris k primaril y du e t o th e inheren t susceptibilit y o f

th e conceptus . 13.6. 1 Childre n a s aPopulatio n a tRis k Childre n ar e developin g an dgrowin g organism s exhibitin g certai n difference s fro madult s i n term s o f basi c physiologi c mechanisms , capabilit y o f copin g withphysiologi c stress , an dthei r relativ e metabol

is mo f lead . Also , th e behavio r o f childre n fre

quentl y place s the min differen t relationshi p t o source s o f

lea di n th e environment , thereb y enhanc

in g th e opportunit y fo r the mt o absor b lead . Furthermore , th e occurrenc e o f excessiv e exposur e ofte n i s no t

realize dunti l seriou s har mi s done . Youn g childre n d o no t

readil y communicat e amedi

ca l histor y o f

lea dexposure , th e earl y sign s o f suc h bein g commo n t o s o man y othe r diseas e state s tha t lea di s frequentl y no t

recognize dearl y a s apossibl e etiologica l facto r

contributin g t o th e manifestatio n o f othe r symptoms . 13.6.1. 1 INHEREN T SUSCEPTIBILIT Y O F TH E YOUN G Discussio n o f

th e physiologica l vulnerabilit y o f th e youn g mus t

addres s tw o discret e areas . No t onl y shoul dth e basi c physiologica l difference s b e con sidere dtha t

on e woul dexpec t

t o predispos e childre n t o aheightene dvulnerabilit y t o lead , bu t als o th e ac tua l clinica l evidenc e mus t b e considere dtha t

show s suc hvulnerabilt y doe s indee dexist . I n Chapte r

10 , Sectio n 10. 6 wa s devote dt o th e metaboli c consideration s in identifyin g susceptibl e subgroups . Factor s discusse di n tha t sectio n in

cluded : (1 ) greate r

lea dintak e o f

infant s o n ape r uni t bod y weigh t

basis , whic hi s probabl y relate dt o greate r calori c an dwate r

requirement ; (2 ) greate r intak e a s wel l a s net . absorptio n (se e G I section) , greate r ne t respirator y intak e a s wel l a s greate r ne t absorptio n an dretentio n fro mth e G I tract ; (3 ) rapi d growt hrat e ma y reduc e th e margi n o f safet y agains t avariet y o f

stresse s includin g iron , calcium , an d vitami n deficiency ; (4 ) dietar y habit s o f childre n ar e quit e differen t

fro madults ; norma l hand-to-mout h activit y probabl y result s in th e transfe r o f lead-con

taminate ddus t

an ddir t

vi athum b suckin g o r i n retrieva l o f

dirt-contaminate dfoodstuffs ; (5 ) th e metaboli c requirement s fo r protein , calcium , an d iro n ar e s o grea t

relativ e t o intak e tha t anegativ e balanc e in thes e factor s ma y exist ; (6 ) in ver y youn g childre n metaboli c pathway s an dfactor s suc ha s th e blood-brai n barrie r

ar e know n t o b e incompletel y developed ; an d(7 ) partitionin g o f lea di n th e bone s o f childre n i s differen t

fro mtha t

o f adults . Onl y 6 0 t o 6 5 percen t

o f th e lea dbod y burde n i s i n th e bone s o f children , an dthi s fractio n ma y b e mor e labile . Hematologi c an dneurologi c effect s i n childre n hav e bee n show n t o hav e lowe r threshold s pe r

uni t o f bloo dlea dtha n i n adults . I n particular , th e lowes t observe deffec t

level s fo r

FE P an danemi aar e lowe r fo r childre n tha n adults . Wit hreferenc e t o neurologi c effects , th e onse t o f encephalopath y an d othe r injur y t o th e nervou s syste mappear s t o var y bot hregardin g likel y lowe r threshold s i n childre n fo r som e effect s an din . th e typica l patter n o f neurologi c effect s presented , e.g. , in encephalopath y o r othe r CN S deficit s bein g mor e commo n i n childre n versu s periphera l neuropath y bein g mor e ofte n see n i n adults . No t onl y ar e th e effect s mor e acut e i n childre n tha n i n adults , bu t als o th e neurologi c sequela e ar e usuall y muc hmor e sever e i n children . Upo n carefu l examinatio n o f th e data , it

shoul db e note dtha t

certai n geographi c o r

socioeconomi c fac

13-1 1P.6 4

tor s appea r

t o emerg e a s importan t factor s deter

minin g th e differentia l susceptibilit y o f som e group s o f childre n fo r

lead-induce dneurologi c damage . Tha t is , ther e seem s t o b e distinc t variatio n i n effect s o r alac k thereo f a s reporte dfo r

childre n i n differen t studie s dependin g upo n th e geographi c area s fro m whic hth e stud y population s wer e drawn . Fo r exam ple , th e few credibl e report s o f lea dencephalopath y i n childre n a t

bloo dlea dlevel s les s tha n 10 0 ug/d l al l concer n childre n fro minner-cit y areas . Similarly , statisticall y significan t effect s o r

border

lin e effect s indicativ e o f mor e subtl e neurobe

haviora l deficit s i n lead-expose dchildre n a t moderatel y elevate dbloo dlea dlevel s hav e bee n re porte dfo r

group s o f

childre n draw n fro minner-cit y population s o f

urba n centers . I n contrast , onl y afew statisticall y significan t

neurobehaviora l effect s hav e yet bee n reporte dfo r

population s o f

childre n ex periencin g simila r

elevation s in bloo dlea dlevels , bu t residin g nea r

primar y smelte r

facilitie s i n semi

rura l areas . On e canno t

determin e withan y certaint y th e specifi c factor s tha t

migh t contribut e t o th e apparen t differentia l sensitivit y o f inner-cit y childre n t o th e neurobehaviora l effect s o f lead . Severa l possibilities , however , migh t b e reasonabl y con sidered , includin g th e following : 1 . Parameter s o f

lea dexposur e probabl y differe dsubstantiall y fo r th e population s unde r study ; th e smelte r

are achildren , fo r example , may hav e experience dmuc hmor e gradua l accumulation s o f lea ddurin g th e cours e o f

long-term , low-leve l exposure s versu s probabl e repeate dbrie f episode s o f somewha t

highe r leve l exposure s bein g superimpose do n an y long-term , low-leve l exposure s fo r

th e inner-cit y children . 2 . Th e exposure s o f

th e smelte r

childre n likel y include dsignificantl y highe r level s o f

othe r metalli c species , e.g. , zinc , tha t ar e know n t o reduc e th e pathologica l impac t o f lea do n man y orga n systems . 3 . Difference s i n nutritiona l statu s likel y ex iste dbetwee n th e smelte r an dinner-cit y children , wit hth e latte r probabl y havin g a highe r incidenc e o f

iron , calcium , an d vitami n deficiency ; o r

othe r difference s i n dietar y conten t

an dhabit s migh t

b e invoke d a s a n explanation . 4 . Interaction s betwee n lea dexposure s an d othe r factor s associate dwit hth e stresse s o f urba n versu s nonurba n livin g ma y als o con tribut e t o th e apparen t differentia l suscep tibilit y o f

inner-cit y chilren . 13.6.1. 2 EXPOSUR E CONSIDERATION S Children' s dietar y habit s a s wel l a s th e diet s them

selve s diffe r

markedl y fro madult s and , a s aresult , plac e childre n i n adifferen t relationshi p t o severa l source s o f

lead . Th e dominanc e o f canne dmil k

an d processe dbab y foo di n th e die t o f man y youn g childre n i s an importan t facto r i s assessin g thei r

ex posur e t o lea dsinc e bot hthos e foodstuffs hav e bee n show n t o contai n highe r amount s o f

lea dtha n com ponent s o f

th e adul t

diet . Th e importanc e o f thes e lea dsource s i s no t

thei r relationshi p t o airborn e lea d directl y but , rather , thei r rol e in providin g ahighe r baselin e lea dburde n t o whic hth e airborn e contribu

tio n i s adde d Childre n ordinaril y underg o astag e o f develop

men t in whic hthe y exhibi t

mouthin g behavior , fo r example , thumbsucking . A t thi s tim e the y ar e a t

ris k o f pickin g u p lead-contaminate dsoi l an ddus t o n thei r hand s an dhenc e int o thei r mouth s wher e i t

ca n b e absorbed . Scientifi c evidenc e documentin g a t leas t th e firs t par t o f th e chai n i s available . Ther e is , however , a n abnorma l extensio n o f th e mouthin g behavior , calle dpica , whic hoccur s i n som e children . Althoug hdiagnosi s o f thi s i s difficult , childre n wh o exhibi t thi s trai t

hav e bee n show n t o purposefull y ea t nonfoo ditems . Muc ho f th e lead-base dpain t

proble mi s know n t o occu r becaus e childre n actuall y inges t chip s o f

leade d paint . 13.6. 2 Pregnan tWome n an d th e Conceptu s a s a Populatio n a tRis k Ther e ar e som e rathe r

inconclusiv e dat aindicat

in g tha t wome n ma y i n genera l b e at somewha t

high

e r ris k t o lea dtha n men . However , pregnan t wome n an dthei r concept i a s asubgrou p ar e demonstrabl y a t highe r risk . I t shoul db e pointe dou t that , i n fact , it reall y i s no t

th e pregnan t

woma n per

se wh o i s a t greates t ris k but , rather , th e unbor n chil dsh e i s carrying . Becaus e o f

obstetri c complications , how

ever , th e mothe r

hersel f ca n als o b e a t

somewha t greate r risk . Thi s sectio n will firs t describ e th e genera l evidenc e fo r

al l wome n an dthe n th e evi

denc e tha t

pertain s t o pregnan t

wome n exclusively . Studie s hav e demonstrate dtha t women , lik e children , in genera l ten dt o sho w aheightene d respons e o f

erythrocyt e protoporphyri n level s upo n exposur e t o lead . Th e exac t reaso n fo r

thi s heightene drespons e i s no t know n bu t

ma y relat e t o endocrin e difference s betwee n me n an dwomen . I n 13-1 2P.6 5

particular , th e level s o f testosteron e ma y pla y arol e i n thi s response . A s state dabove , th e primar y reaso n pregnan t wome n ar e ahigh-ris k

grou p i s becaus e o f

th e fetu s eac hi s carrying . I n addition , ther e i s som e sugges tiv e evidenc e tha t

lea dexposure s ma y affec t mater na l complication s o f

delivery . Wit hreferenc e t o materna l complication s at delivery , informatio n i n th e literatur e suggest s th e incidenc e o f

preter mdeliver y an dprematur e mem bran e ruptur e relate s t o materna l bloo dlea dlevel . Furthe r stud y o f

thi s relationshi p a s wel l a s studie s relatin g t o discret e healt heffect s i n th e newbor n ar e required . Vulnerabilit y o f

th e developin g fetu s t o lea dex posur e arisin g fro mtransplacenta l transfe r o f mother' s bloo dlea dconten t wa s discusse di n Sectio n 11.6 . Thi s proces s start s a t th e en do f

th e firs t tri

mester . Cor dbloo dstudie s involvin g mother-infan t pair s repeatedl y hav e show n acorrelatio n betwee n materna l an dfeta l bloo dlea dlevels . Furthermore , th e observe dpositiv e correlatio n o f urinar y AL A level s withbloo dlea dlevel s i n newborn s indicate s tha t som e heme-biosyntheti c derangemen t i s ap paren t a t birt han dmus t

therefor e hav e commence d in utero. Furthe r suggestiv e evidence , cite di n Chapte r 11 , ha s bee n advance dfo r prenata l lea dexposure s o f fetuse s possibl y leadin g t o late r highe r instance s o f postnata l menta l retardatio n amon g th e affecte doff

spring . Th e availabl e dat aar e insufficien t t o stat e withan y certaint y tha t

suc heffect s occu r

o r t o deter

min e wit han y precisio n wha t level s o f lea dexposur e migh t b e require dprio r

t o o r durin g pregnanc y i n orde r t o produc e suc heffects . 1 3 7 DESCRIPTIO N O F U.S . POPULATIO N I N RELATIO N T O PROBABL E LEA D EX POSURE S I n thi s sectio n estimate s ar e provide do f th e num be r o f individual s potentiall y a t ris k t o lea dex posures . Unfortunatel y th e lates t censu s dat aar e onl y fro m1970, 8 althoug hsom e estimate s ar e avail

abl e fro mth e Nationa l Cente r fo r Healt hStatistic s fo r 1975. 9 Thi s i s unfortunat e sinc e som e significan t change s ar e though t

t o hav e occurre di n th e popula

tio n structur e sinc e th e 197 0 census . Becaus e mos t

lea dexposures , exceptin g area s with primar y lea dsmelters , occu r in wha t th e Burea u o f th e Censu s call s urba n areas , a n estimat e o f th e po tentia l ris k

o f airborn e lea dexposur e ca n b e mad e fro mth e tota l urba n populatio n o f th e Unite dStates . Tha t thi s ma y b e an acceptabl e firs t approximatio n ca n b e gleane db y comparin g th e frequenc y distri

butio n o f ai r lea dconcentration s fo r urba n an drura l Nationa l Ai r

Samplin g Networ k

station s i

n Chapte r 7 . Thi s compariso n readil y show s adistinc t differenc e i n exposur e betwee n th e tw o type s o f sta tions . Base do n examinatio n o f th e urba n station s a s wel l a s o f

literatur e dat ao n bot hai r lea dan dsoi l an ddus t lea dvalues , astron g cas e ca n b e mad e t o suppor t th e assumptio n tha t

th e are awhic hth e Burea u o f

th e Censu s call s th e centra l cit y o f th e ur ba n area s i s at

eve n highe r

ris k o f lea dexposure . Therefore , i n regar dt o exposure s othe r tha n localize dpoin t

stationar y source s o f lead , th e populatio n at

ris k i s th e urba n on e and , in particular , th e centra l cit y residents . Fo r th e Unite dState s i n 1970 , thes e value s wer e 14 9 an d6 4 millio n people , respectively 8 (Tabl e 13-5) . Fro mth e tabl e it ca n TABL E 13-5 . POPULATIO N AN D PERCEN T DISTRIBUTION , URBA N AN D RURAL , BY RAC E 197 0 CENSUS 4

in n (10° ) Urba n Insid e urbanize d area s Centra l citie s Urba n fringe s Outsid e urbanize d area s Rura l Total . Unite d State s 128.773(72.4 ) 100.952(56.8 ) 49.54 7 (27.9 ) 51.405(28.9 ) 27.822(15.7 ) 48.97 6 (27.6 ) 177.77 3 20,55 2 (80.7 ) 17,49 5 (68.7 ) 14,37 5 (56.5 ) 3,12 0 (12.3 ) 3,05 7 (12.0 ) 4,91 1 (19.3 ) 25.46 3 149.325(73.5 ) 118.447(58.3 ) 63.922(31.5 ) 54.52 5 (26.8 ) 30.878(15.2 ) 53.88 7 (26.5 ) 203,21 2 readil y b e see n tha t

ahighe r proportio n o f

th e non whit e populatio n live s i n urba n area s tha n white s (80. 7 versu s 72. 4 percent ) an di s possibl y subjec t t o greate r exposur e t o airborn e lead . Furthermore , thi s disparit y i s eve n greate r whe n on e consider s th e centra l cit y populatio n only , whic hma y b e subjec t t o eve n highe r

level s o f lea dpollutio n fro mamultitud e o f sources . Fro mth e previou s discussio n o f population s a t risk , however , tw o subgroup s o f thi s tota l populatio n wer e define da s bein g a t eve n highe r

ris k — children , especiall y thos e unde r 5 , an dpregnan t 13-1 3TABL E 13-6 . NUMBE R O F BIRTH S B Y RAC E AN D SIZ E O F POPULATION 8 P.6 6

Urba n area s o f give n siz e fro m 197 0 censu s Birth s Whit e 772.23 0 286.70 6 600.16 6 1.432.162 3.091.26 4 Blac k 321.41 2 37.02 4 65.79 0 148.13 6 572.36 2 Birth s Other s 24.39 4 4.18 2 10.39 4 28.79 0 67.76 0 Tota l

1.118.03 6 327.91 2 676.35 0 1,609.08 8 3.731,38 6 > 100,00 0 50-99,99 9 10-49,99 9 59,99 9 Tota l

Urba n area s o f give n Siz e fro m 1975 censu s Whit e Blac k Other s Tota l > 100,00 0 50-99,99 9 10-49,99 9 59,99 9 571.47 8 222.73 5 478.38 2 1.279.40 1 276.38 7 37.88 5 64.48 1 132.82 8 26.33 2 5.92 1 13.03 9 35.32 9 874,19 7

266.54 1 555.90 2 1,447.55 8 Tota l 2.551.99 6 511.58 1 80.62 1 3.144,19 8 women . Ther e i s insufficien t evidenc e at

thi s tim e t o determin e whethe r

an y racia l o r

ethni c grou p suffer s an innat e susceptibilit y t o lead . I n th e Unite dState s in 197 0 abou t 1 2 millio n childre n unde r

5 year s o f

ag e live din urba n areas . Approximatel y 5 millio n o f thes e childre n live din centra l cit y areas. 8 Sinc e between-censu s populatio n estimate s ar e no t

availabl e fo r

urban-rura l com parisons , th e onl y way t o us e th e 197 5 populatio n estimate s i s t o assum e tha t th e percen t

distributio n obtaine din 197 0 stil l hold s true . I f in fac t tha t i s th e case , th e mor e recen t

estimate s woul db e abou t 1 1 millio n children , i n urbanize darea s an d4. 6 millio n in th e centra l city . A n estimat e mad e b y th e Nationa l Burea u o f

Standard s o f

th e tota l chil dpopulatio n withbloo dlea dvalue s equa l t o o r greate r tha n 4 0 figldl i n arecen t

yea r wa s 600,000. 1 0 Thi s tota l i s clearl y acaus e fo r

concer n i n vie w o f

th e healt hdat a presente din Sectio n 13. 4 above . O f course , th e us e o f thi s figure , base do n th e man y lead-screenin g pro gram s conducte din thi s country , i s no t mean t t o im

pl y tha t al l o f thes e value s resulte dfro mairborn e lead . The y probabl y d o not , sinc e pain t lea dex posure s ar e a n additiona l importan t source . But , o n th e othe r hand , th e additio n o f a n airborn e com ponen t o f lea dexposur e o n to p o f thes e level s woul d adversel y affec t

th e publi c health . If

airborn e lea d wer e th e onl y contributio n t o thes e children' s lea d values , th e potentia l healt heffect s ascribabl e t o tha t exposur e coul db e significant . Th e difficult y in estimatin g th e numbe r o f preg nan t wome n expose dt o ai r

lea di s eve n greater ; thi s i s becaus e th e numbe r of. pregnan t

wome n i s no t tabulate do n a n urban-rura l basis . Therefore , fo r thi s document , th e numbe r o f pregnan t

wome n will b e estimate dfro mth e numbe r o f liv e birth s (Tabl e 13-6). 8 Unfortunatel y thes e dat aals o ar e no t tabu

late do n a n urban-rura l basi s but , rather , o n a populatio n siz e o f

plac e o f residence . I t

ca n readil y b e see n tha t

th e tota l numbe r

o f birth s ha s decline d i n th e tim e 197 0 t o 1975 . I f on e assume s onl y th e highes t populatio n siz e categor y t o b e a t ris k o f lea d exposure , ther e ar e stil l almos t 900,00 0 newborn s a t ris k o f lea dabsorptio n fro mthei r mothers . 13. 8 REFERENCE S FO RCHAPTE R1 3 1 . Nordman , C . H . Environmenta l lea dexposur e i n Finland . A stud y o n selecte dpopulatio n groups . Dissertation . Universit y o f

Helsinki , Helsinki . 1975 . 2 . Finney , D . J . Statistiea l metho di n biologica l assay . Charle s Griffi n an dCo. , London . 1971 . p . 5 . 3 . Hernberg , S . Biochemical . Subclinica l an dClinica l Response s t o Lea dan dThei r Relatio n t o Differen t

Ex

posur e Levels , a s Indicate db y th e Concentratio n o f Lea d i n Blood . In: Effect s an dDose-Respons e Relationship s o f Toxi c Metals . G . F . Nordber g (ed.) . Elsevie r Scientifi c Publishin g Co. . Amsterdam . 1976 . Par t BIS . 4 . Zielhuis , R . L . Dose-respons e relationship s fo r inorgani c lead : I . Biochemica l an dhematologica l responses . Int . Arch . Occup . Hlth . 55:1-18 . 1975 . 5 . Roels , H. , Buchet , J . P. , R . Lawrie , an dG . Hubermont . Impac t o f ai r pollutio n b y lea do n th e hem e biosyntheti c pathwa y i n school-ag e children . Arch . Environ . Hlth . J/: 3 10-316 , 1976 . 6 . Piomelli . S . Reanalysi s o f dat afro mS . Piomelli . C . Sea

man , D . Zullow . A . Curran , an dB . Danidow . Metaboli c evidenc e o f

lea dtoxicit y i n "normal " urba n children . Clin . Res . 25.-495A . 1977 . Presente dt o Environmenta l Protectio n Agenc y staf f an dconsultants . Researc h Triangl e Park . N.C . Septembe r 28 , 1977 . 13-1 47 . Azar , A. . R . D . Snee . an dK . Habibi . A n epidemiologica l 9 . U . S . Nationa l Cente r for Healt hStatistics , Vita l Statistic s approac ht o communit y ai r lea dexposur e usin g persona l o f th e U . S. . 1975 , Dat afo r 197 5 Births . Unpublishe d- ai r samplers . Environ . Qual . Saf.Suppl . 11:254-290 . 1975 . provide db y NCHS . 8 . U . S . Burea u o f

th e Census , Statistica l Abstract s o f th e 10 . Nationa l Burea u o f Standards . Surve y Manua l fo r Unite dStates . 197 6 (97t hEd.) . Washington , D.C . 1976 . p . Estimatin g th e Incidenc e o f Lea dPain t

i n Housing . NB S 18 , Tabl e 19 . ' Technica l Not e 921 , Septembe r 1976 .

13-1 5

# APPENDIX A GLOSSARY * Absorptio n (o f

lead) : Transfe r

o f lea dint o a n organ is mvi aintestina l wall , alveola r surface , o r

skin . Accumulatio n (o f

lead) : Ne t

positiv e differenc e be

twee n intak e an doutpu t o f lea dove r

a n extende d period . Acety l coenzym e A (CoA) : Coenzyme , derive dprin

cipall y fro mth e metabolis mo f glucos e an dfatt y acids , tha t

take s par t

i n man y biologica l acetyla

tio n reactions ; oxidize di n th e Kreb s cycle . Acetylcholine : Compoun drelease dfro mcertai n autonomi c nerv e endings ; act s i n th e transmissio n o f nerv e impulse s t o excitabl e membranes . Acetylcholinesterase : Enzym e i n excitabl e membrane s tha t

inactivate s acetylcholine . /3-Acety l glucosaminadase : Enzym e tha t hydrolyze s th e termina l glucosaminidi c bond s o f odd-num

bere doligosaccharide s t o yiel dN-acetyl

glucosamin e an dth e nex t lowe r even-numbere d oligosaccharide . Acid-fast : Describe s acel l o r bacteriu mtha t

retain s ady e tha t

ha s anegativel y charge dmolecule . Aci dphosphatase : Enzym e tha t hydrolyzes , i n a n aci dmedium , monophosphori c esters , wit h liberatio n o f

inorgani c phosphate . Adenocarcinoma : Carcinom aderive dfro mglandu

la r tissu e o r i n whic h th e tumo r

cell s formrecog nizabl e glandula r

structures . Adenoma : Benig n epithelia l tumo r i n whic hth e cell s for mrecognizabl e glandula r structure s o r

i n whic hth e cell s ar e clearl y derive dfro mglandula r epithelium . Adenosin e diphosphat e (ADP) : Coenzym e com pose do f

adenosin e an dtw o molecule s o f phosphori c acid ; importan t i n intermediat e cellu

la r metabolism ; aproduc t o f th e hydrolysi s o f adenosin e triphosphat e (ATP) . Adenosin e triphosphat e (ATP) : Nucleotid e occur rin g i n al l cells , wher e i t serve s i n th e storag e o f energ y an di n th e transfe r o f energ y in metaboli c processes ; compose do f adenosin e an dthre e molecule s o f

phosphori c acid . "Compile d from standar d referenc e work s and , t o alesse rextent , from informatio n furnishe d by expert s in th e respectiv e disciplines . Adenosin e triphosphatas e (ATPase) : Enzym e tha t mediate s th e remova l o f wate r fro mATP : AT P + H 2 0 —AD P + orthophosphate . Adeny l cyclase : Enzym e tha t catalyze s th e forma

tio n o f cycli c adenosine-3' , 5'-monophosphat e (cycli c AMP) . Adenyli c acid : (1 ) Generi c nam e fo r agrou p o f isomeri c nucleotides ; (2 ) Phosphori c aci deste r o f adenosine ; als o know n a s adenosin e monophosphat e (AMP) . Adrenaline : Se e Epinephrine . Adrenergic : Describe s th e chemica l activit y o f epinephrin e o r

epinephrine-lik e substances . Adrenergi c synapse : Synaps e a t whic h norepinephrin e i s liberate dwhe n anerv e impuls e passes . Advection : Proces s o f

transpor t

o f a n atmospheri c property , o r

substanc e withi n th e atmosphere , solel y b y th e mas s motio n o f th e atmosphere . Aerodynami c diameter : Expressio n o f aerodynami c behavio r o f a n irregularl y shape dparticl e i n term s o f th e diamete r

o f a n idealize dparticle ; tha t is , aerodynami c diamete r i s th e diamete r

o f a spher e o f

uni t densit y tha t

ha s aerodynami c behavio r identica l t o tha t

o f th e particl e i n ques tion . Thus , particle s havin g th e sam e aero dynami c diamete r

ma y hav e differen t

dimension s an dshapes . Aerodynami c drag : Aerodynami c resistance ; retard

in g forc e tha t

act s upo n abod y movin g throug ha gaseou s flui dan dtha t

i s paralle l wit hth e direc

tio n o f motio n o f

th e body . Aerodynami c particl e size : Spher e o f uni t densit y tha t ha s aerodynami c behavio r identica l t o tha t

o f th e particl e i n question . Aerosol : Syste mi n whic hth e dispersio n mediu mi s a ga s an dth e disperse dphase—compose do f soli d particle s o r

liqui ddroplets—doe s no t settl e ou t unde r th e influenc e o f

gravity . Aeroso l particles : Soli dparticle s 10 l 2 t o 10 ' fim i n diameter , disperse di n agas .P.6 9

Agglomeration : Proces s b y whic hprecipitatio n par ticle s gro w b y collisio n wit ha n assimilatio n o f clou dparticle s o r

othe r precipitatio n particles . Aitke n dus t

counter : Instrumen t

fo r determinin g dus t conten t o f th e atmosphere ; asampl e o f ai r i s mixed , i n a n expandabl e chamber , wit halarg e volum e o f

dust-fre e ai r

containin g wate r

vapor . Upo n sudde n expansion , th e chambe r cool s adiabaticall y belo w it s dewpoint , an ddroplet s for mwit hth e dus t

particle s a s nucle i an dar e counte db y mean s o f

agri dunde r

amicroscope . Aitke n nuclei : Microscopi c particle s i n th e at mospher e tha t

serv e a s condensatio n nucle i fo r drople t growt hdurin g th e rapi dadiabati c expan sio n produce db y an Aitke n dus t counte r (se e above) . Aldolase : Enzym e tha t

act s o n aketose-1-phosphat e t o yiel ddihydroxy-aceton e phosphat e plu s a n aldehyde ; e.g. , fructose-1 , 6-diphosphat e = dihydroxyaceton e phosphat e + D

- glyceraldehyde-3-phosphate . Alkalin e phosphatase : Enzym e tha t hydrolyzes , i n alkalin e medium , monophosphori c esters , wit h liberatio n o f

inorgani c phosphate ; foun di n plasm aan dserum , bone , etc . Alkalinity : Exces s o f

hydroxy l ion s ove r

hydroge n ions , generall y expresse da s milliequivalent s pe r liter . Alveola r

macrophages : Rounde dgranula r phagocyti c cells , withi n th e alveol i o f th e lungs , tha t inges t inhale dmaterial . Ambien t air : Th e surrounding , well-mixe dair . Aminoacy l synthetase : Enzym e tha t catalyze s th e couple dreaction s o f

amin o aci dactivatio n i n whic ha n amin o aci di s first attache dt o adenosin e monophosphat e an dthe n t o atransfer-RN A molecule . e-Amin o grou p o f

lysine : Th e amin o group , NH 2 , at tache dt o e , o r

5th , carbo n ato mfro mth e carbox

y l carbo n i n th e amin o acid , lysine : H 2 N-CH 2 - C H 2 -C H 2 -C H 2 -C H (N H 2 )-COOH . 8-Aminolevulini c aci d(ALA , o r 8-ALA) : COOH

CH 2 -CH 2 -CO-CH 2 -NH 2 ; intermediat e i n th e bio

synthesi s o f

heme-containin g compounds ; forme d fro msuccinyl-coenzym e A an dglycine . 8-Aminolevulini c aci ddehydratas e (ALAD) : Enzym e i n hem e biosyntheti c pathwa y tha t medi

ate s formatio n o f

porphobilinoge n fro m8

- aminolevulini c acid . 8-Aminolevulini c aci dsynthetas e (ALAS) : Enzym e i n hem e biosyntheti c pathwa y tha t mediate s th e formatio n o f

8-aminolevulini c aci dfro msuc cinyl-Co A vi a2-amino-3-ketoadipate . Amphetamine : a-Methylphenethylamine . Dru g use dt o stimulat e th e centra l nervou s system , in

creas e bloo dpressure , reduc e appetite , an d reduc e nasa l congestion . Abus e ma y lea dt o de

pendence , characterize db y stron g psychi c depen

denc e associate dwitha n increas e i n RE M (rapid

eye-movement ) sleep , hunger , apathy , an d depression . Anamnesti c response : Rapidl y increase dantibod y leve l followin g renewe dcontac t wit haspecifi c antigen , eve n afte r

severa l years . Anodi c strippin g voltammetry : A n electrochemica l metho do f

analysis . Anophthalmia : Developmenta l defec t characterize d b y complet e absenc e o f

th e eye s o r

b y th e presenc e o f vestigia l eyes . Anorexia : Los s o f

appetite . Anoxia : Relativ e lac k

o f oxygen ; cause db y inade

quat e perfusio n o f

tissue s b y bloo dcarryin g nor ma l amount s o f

oxyge n o r

b y norma l perfusio n o f bloo dcarryin g reduce damount s o f oxygen . Antipyrin e (C,,H 12 ON 2 ) : Compoun duse da s a n an tipyretic , analgesic , an dantirheumati c drug . Are asource : Consist s o f anumbe r

o f poin t source s arrange di n atwo-dimensiona l array . Astrocyti c proliferatio n (astrocytosis) : Proliferatio n o f astrocyte s owin g t o th e destructio n o f nearb y neuron s durin g ahypoxi c o r hypoglycemi c episode . Ataxia : Failur e o f

muscula r

coordination . Atmospheri c turbulence : Motio n o f th e ai r (o r othe r fluids ) i n whic hloca l velocitie s an dpressure s fluctuat e irregularl y i n arando mmanner . Avoidanc e task : Behaviora l testin g procedur e use d t o measur e a n animal' s avoidanc e an descap e per formance . I n aone-wa y tas k onl y on e respons e i s appropriate , wherea s i n atwo-wa y tas k eithe r o f tw o response s i s appropriate , dependin g o n th e existin g tes t

conditions . Axona l degeneration : Degeneratio n o f axons , th e processe s o r

nerv e fiber s tha t

carr y th e unidirec

tiona l nerv e impuls e awa y fro mth e nerv e cel l body . Balanc e experiments : Experiment s o n ma n o r othe r animal s tha t

involv e quantitativ e measurement s o f intak e (vi arespiratio n an dingestion ) an dlos s (vi aexhalatio n an dexcretion ) o f aspecifi c ele

men t o r substance . A positiv e balanc e mean s tha t mor e i s take n i n tha n i s los t ove r aspecifi c time . Basophili c stippling : Spotte dappearanc e o f relativel y immatur e re dbloo dcell s tha t contai n cytoplasmi c materia l tha t stain s deepl y wit hbasi c dyes . A- 2P.7 0

Biosphere : Th e par t

o f th e earth' s crust , waters , an d atmospher e wher e livin g organism s ca n subsist . Blood-brai n barrier : Th e barrie r create db y semi

permeabl e cel l wall s an dmembrane s t o passag e o f som e molecule s fro mth e bloo dt o th e cell s o f th e centra l nervou s system . Bod y burden : Th e tota l amoun t o f aspecifi c sub

stanc e (fo r

example , lead ) i n a n organism , includ

in g th e amoun t

stored , th e amoun t

tha t i s mobile , an dth e amoun t

absorbed . Bon denergy : Th e enthalp y chang e tha t accompanie s th e breakin g o f

achemica l bon dbetwee n tw o atoms . Th e tota l bon denerg y o f amolecul e give s ameasur e o f

it s thermodynami c stability . Boundar y layer : Laye r o f flui din th e immediat e vicinit y o f

aboundin g surface ; refer s ambiguousl y t o th e (1 ) laminar , (2 ) turbulent , (3 ) planetary , o r (4 ) surfac e boundar y layers . Brainstem : Stemlik e portio n o f th e brai n connectin g th e cerebra l hemisphere s wit hth e spina l cord : Bremsstrahlung : Radiatio n tha t i s emitte db y a n electro n accelerate din it s collisio n wit hth e nucleu s o f

a n atom . Brownia n movement : Rando mmovement s o f dis

perse dsmal l particle s suspende di n afluid ; result s fro mrando mcollision s betwee n th e molecule s o f

th e dispersin g mediu man dth e parti

cle s o f th e disperse dphase . CaEDTA : Edathami l calciu mdisodium , whic hi s th e calciu mdisodiu msal t o f ethylene

- diaminetetraacetate , achelatin g agent . CaEDT A i s use di n th e study , diagnosis , an dtreatmen t o f poisonin g b y variou s heav y metals , includin g lead . CaEDT A mobilizatio n test : Tes t i n whic haknow n quantit y o f

CaEDT A i s injecte dparenterall y an d th e amoun t

o f lea dexcrete di n urin e durin g a know n perio dbeginnin g immediatel y thereafte r i s measured . Thi s procedur e i s use dbot hclinicall y an dexperimentall y an di s though t t o provid e a n inde x o f th e mobil e fractio n o f th e tota l bod y burde n o f

lead . Carcinogenesis : Developmen t o f carcinoma ; or , i n mor e recen t

usage , producin g an y kin do f malig

nancy . Carcinoma : Malignan t ne w growt hmad e u p o f epithelia l cell s tendin g t o infiltrat e th e surround

in g tissue s an dgiv e ris e t o metastases . Cascad e impactors : Low-spee dimpactio n devic e fo r us e i n samplin g bot hsoli dan dliqui datmospheri c suspensoids ; consist s o f fou r pair s o f jet s (eac ho f progressivel y smalle r size ) an dsamplin g plate s workin g i n serie s an ddesigne ds o tha t eac hplat e collect s particle s o f

on e siz e range . Catalase : Enzym e tha t

catalyze s th e decompositio n o f hydroge n peroxide ; contain s fou r hemati n group s pe r

molecule ; foun di n live r an dre dbloo d cells . Catecholamines : Grou p o f sympathomimeti c amine s containin g acatecho l moiety ; especiall y epinephrine , norepinephrine , an ddopamine . Catenation : Propert y o f a n elemen t

tha t enable s it

t o lin k t o itsel f t o formchains , e.g. , carbon . Cerebellum : Larg e dorsall y projectin g par t o f th e brai n havin g th e specia l functio n o f muscl e coor dinatio n an dmaintenanc e o f equilibrium . Cerebra l anoxia : Relativ e lac k o f oxyge n i n th e brain . Cerebra l cortex : Thi n laye r o f gra y matte r

o n th e surfac e o f

th e cerebra l hemisphere , folde dint o gyri , wit habou t

two-third s o f

it s are aburie di n th e depth s o f

th e fissures . Chelate : Chemica l compoun di n whic hametalli c io n i s sequestere dan dboun dint o arin g b y covalen t bond s t o tw o o r

mor e nonmetalli c atom s i n th e sam e molecule . Chelant : Chemica l compoun dtha t will reac t

wit h metal s t o for mchelates ; achelatin g agent . Cholinergic : Stimulated , activated , o r transmitte d b y acetylcholine ; applie dt o thos e nerv e fiber s tha t liberat e acetylcholin e a t asynaps e whe n a nerv e impuls e passes . Cholinesterase : Enzym e tha t catalyze s th e hy

drolysi s o f

acylcholin e t o cholin e an da n anion . Chemica l energy : Energ y produce do r absorbe di n th e proces s o f

achemica l reaction . Chi-squar e test : Tes t

o f statistica l significanc e base d o n frequenc y o f

occurrence ; use dt o tes t pro babilitie s o r

probabilit y distribution s (goodnes s o f fit), statistica l dependenc e o r independenc e (association) , an dcommo n populatio n (homogeneity) . Chlorinity : Measur e o f chlorid e content , b y mas s (g/kg) , o f water ; sometime s determine dt o permi t calculatio n o f

salinity . Choroi dplexus : An y o f th e highl y vascular , folde d processe s tha t

projec t int o th e third , fourth , an d latera l ventricle s o f

th e brain . Chromatid : On e o f

th e pai r

o f stands , forme db y longitudina l splittin g o f achromosome , tha t

ar e joine db y asingl e centromer e i n somati c cell s durin g mitosis ; on e o f

atetra do f

strand s forme d b y lengthwis e splittin g o f paire dchromosome s durin g th e diploten e stag e o f meiosis . A- 3P.7 1



### Chromophore : An

y chemical grou p whos e presenc e give s adecide dcolo r

t o acompoun dan dthat unite dwit hcertai n othe r

group s t o for

mdyes . Chromosomes : Threadlik e structure s i n animal o r plan t nuclei, see

n durin g karyokinesi s (nuclear divisio n characteristi c of

mitosis) , tha t

carry th e linearl y arrange dgeneti c material . Chroni c nephritis : Chroni c inflammatio n o f th e kid

neys . Coagulation : Proces s tha t convert s numerou s droplet s into asmalle r

number o f large r pre cipitatio n particles . Coalescence : Mergin g o

f tw o liqui ddrop s int o a singl e large r

drop . Colic : Paroxysmal pai n i n th e abdomen , cause db y spasm , distention , o r

obstructio n o

f an y on e o f th e hollo w viscera . Colloida l materials : Se

e Colloida l system . Colloida l system : A

n intimat e mixtur e o

f tw o sub

stances , on e o

f which , calle dth e disperse dphas e (o r colloid) , i s uniforml y distribute di n afinel y divide dstat e throug hth e secon dsubstanc e (dis

persio n medium) ; th e dispersio n mediumma y b e agas , liquid , o r

solid . Combustio n nucleus : Condensatio n nucleu s forme d a s aresul t

o f industria l o r

natura l combustio n processes . Complement : Comple x protein s i n normal serum that interac t t o combin e wit

hantigen-antibod y complex , producin g lysi s whe n th e antige n i s i

n a n intac t cell ; importan t

i n hos t defens e mechanis m agains t invadin g microorganisms . Complex : Chemical compoun di n whichapart

o f th e molecular bondin g i s o

f th e coordinat e type . Complexing : Formatio n o f acomple x compound ; see Complex . Condensation : Physica

l proces s b

y whichavapo r become s aliqui do r

solid ; opposit e o

f evapora tion . In meteorology , th e ter mi s limite dt o transformatio n o

f vapo r t o aliquid . Condensatio n nucleus : Particle , eithe r liqui do r solid , upo n whichcondensatio n o f water vapo r begin s i n th e atmosphere . Condensatio n particles : Se e Aitke n nuclei . Confidenc e interval : A rang e o f value s (a , < a<a 2 

### ) determine dfromasampl e b y definite rule s s o chosen that , i

n repeate drando msample s fro mth e hypothesize dpopulation , a n arbitaril y fixedpro portio n (1-e ) o

f that rang e will includ e th e tru e value , x , o

f a n estimate dparameter . Th e limits , a , an da 2 

### , ar e calle dconfidenc e limits ; th e relativ e frequenc y (1-e ) wit hwhichthes e limit s includ e a i s calle dth e confidenc e coeffi

cient ; an dth e complementary probability , e , i s calle dth e confidenc e level . A s wit hsignificanc e levels , confidenc e level s ar e commonl y chose n a s .0 5 o r .01 , th e correspondin g confidenc e coeffi

cient s bein g .95 , .99 . Confidenc e interval s shoul dno t b e interprete da s implyin g tha t

th e paramete r

itsel f ha s arang e of values ; it ha s only on e value , a. O n th e othe r hand , th e confidenc e limit s (a p 

### a 2 

### ) , bein g derive d fromasample , ar e rando mvariable s th e value s of whicho n aparticula r

sampl e eithe r

d o o r d o no t includ e th e tru e valu e a o f th e parameter . However , i

n repeate dsamples , acertai n propor tio n (namel y 1-e

) o f thes e interval s wil l includ e a , provide dthat

th e actua l populatio n satisfie d th e initial hypothesis . Contamination : Contac t

wit ha n admixtur e o

f a n un natura l agent , wit

hth e implicatio n tha t

th e amoun t i s measurable . Convection : Atmospheri c motion s tha t ar e predomi

nantl y vertical , resultin g i n vertica l transpor t

an d mixin g o f atmospheri c properties . Convulsions : Violent , involuntary contractio n o r serie s of contraction s o

f th e voluntary muscles . Coproge n III : Coproporphyrinoge n III , a n inter

mediar y metabolit e i

n heme biosynthesis . I t

i s a natura l precurso r

o f heme . Coprogenase : Coproporphyrinogenase , th e enzyme that convert s coproporphyrinoge n II I t o pro toporphyri n IX . Coproporphyrin : Urinary pigment derive dfro

m coproporphyrinogen , a

n intermediat e i

n th e bio

synthesi s o

f heme . Coproporphyrinoge n (syn . coprogen) : A full y reduce dcolorles s tetracarboxyli c tetrapyrrole . Isomer s I an dII I ar e foundi n biologi c systems . Cortex : Se

e Cerebra l cortex . Corpu s callosum : Ban do f nerv e tissu e connectin g th e cerebra l hemisphere s i n ma n an dhigher

mam mals . Corpu s striatum : A subcortica l mas s o f gray an d white substanc e i

n eac hcerebra l hemisphere , con tainin g th e caudat e nucleu s an dth e lentifor m nucleus . Cortica l atrophy : Wastin g awa y o f th e oute r layer(s) , e.g. , o f th e brai n o r

kidney . Creatinine : C 4 

### H 2 

### ON 3 

### ; compoun dforme db y dehydratio n o

f creatine ; foundi

n urine , blood , an dmuscle . Cristae : Inne r

membrane s o

f mitochondria , th e sur face s o f whichar e studde dwit

hroughl y spherical particle s attache dt o th e crista e b y stalks . A- 4P.7 2

Cumulativ e frequenc y distribution : Proportio n o f a distributio n tha t

lie s belo w agive n value . Curie : Uni t

o f radioactivity ; quantit y o f ra dionuclid e tha t

ha s 3. 7 x IO 1 0 disintegration s pe r minut e (dpm) . Cysteine : Amin o aci dtha t occur s a s aconstituen t o f glutation e an do f

cystine . Cytochrom e c : Smal l hem e protei n containin g on e ato mo f iro n pe r molecule ; it s principa l biologi c functio n i s i n electro n transport . Se e Cytochromes . Cytochrom e c oxidas e (cyt . a 3 ) : Enzym e tha t catalyze s th e oxidatio n o f cytochrom e c : 4 reduce dcytochrom e c + 0 2 = 4 oxidize d cytochrom e c + 2H 2 0 . Cytochrom e c reductase : Enzym e tha t catalyze s th e reductio n o f

oxidize dcytochrom e c : NADH 2 + oxidize dcytochrom e c = NA D + reduce d cytochrom e c. Cytochrom e P-450 : afc-type cytochrome , on e o f th e mixed-functio n oxidase s i n th e microsoma l syste mresponsibl e fo r

th e oxidatio n o f

steroid s an ddrug s an dothe r

foreig n compounds . Cytochromes : Comple x protein/hem e respirator y pigment s occurrin g i n plan t an danima l cells , usuall y in mitochondria , tha t functio n a s electro n carrier s i n biologica l oxidation . Demyelination : Destructio n o f th e myelin , afatlik e substanc e formin g asheat haroun dth e nerv e fibers . Density : Rati o o f

mas s o f asubstanc e t o th e volum e occupie db y it

(usuall y expresse di n g/cm 3 ) . Dentine : Als o dentin ; chie f substanc e o r

tissu e o f th e teeth , tha t

surround s th e toot hpul p an di s covere db y ename l o n th e crow n an db y cemen tu mo n th e root s o f

th e teeth . Denve r Developmen t

Screenin g Test : Ratin g scale s employe dt o asses s fou r area s o f

chil ddevelop

ment : (1 ) gros s motor , (2 ) fine motor-adaptive , (3 ) personal-social , an d(4 ) language . Deoxyribonuclei c aci d(DNA) : A nuclei c aci di n th e for mo f adoublestrande dheli x o f alinea r polymer ; mad e u p o f

repeatin g unit s o f

2-deoxy

ribose , phosphate , an dapurin e o r apyrimidine ; carrie r o f geneti c informatio n code di n th e se quenc e o f

purine s o r

pyrimidine s (organi c bases) . Deposition : (1 ) Deposi t o f particle s fro mth e am bien t ai r o r atmospher e ont o asurface ; (2 ) remova l o f

particle s fro minhale dai r b y th e respirator y tract . Detectio n limit : A limi t belo w whic ha n elemen t o r compoun dca n no t

b e detecte db y th e metho do r instrumen t

bein g use dfo r

analysis . Dichotomou s sampler : Air-samplin g devic e tha t separate s particulate s int o tw o fraction s o n th e basi s o f diameter ; th e cutpoin t

varie s withth e siz e o f th e aperture . Diffusion : I n meteorology , th e exchang e o f flui d parcel s betwee n region s i n spac e i n apparentl y rando msmall-scal e motions . p-Dimethylaminobenzaldehyde : Ehrlich' s reagent ; (CH 3 ) 2 N.C 6 H 4 .CHO . Diphenylthiocarbazone : Se e Dithizone . Dispersion : Distributio n o f finel y divide dparticle s in amedium . Dithizone : Diphenylthiocarbazone ; C 6 H 5 N:N-CS

NH»NH-C 6 H 5 ; reagen t use di n th e analysi s o f lead . Dithizon e methods : Colorimetri c method s o f analysi s fo r

lea dtha t

involv e th e reactio n o f lea d withdithizon e t o formlea ddithizonate , whic hi s measure dspectrophotometricall y at 51 0 nm . Dopamine : Hydroxytyramine , produce db y th e decarboxylatio n o f dop a(dihydroxy

- phenylalanine) , whic hi s a n intermediat e produc t in th e synthesi s o f

norepinephrine . Dorsa l roo t

ganglion : Grou p o f

sensor y nerv e cel l bodie s locate do n th e posterio r roo t o f eac hspina l nerve ; join s peripherall y withventral , o r motor , roo t t o formth e nerv e befor e it passe s outsid e th e vertebra l column . Downwind : I n th e sam e directio n tha t th e win di s blowing ; o n o r

towar dth e le e side . Dr y deposition : Th e deposi t o f particle s o n asurfac e in th e absenc e o f

precipitation . Dust : Soli dmaterial s suspende di n th e atmospher e i n th e for mo f

smal l irregula r

particles , man y o f whic har e microscopi c i n size . Dustfall : Dr y depositio n o f airborn e dus t

particles . Dysoria : An y abnormalit y o f vascula r permeability . E. coli: Short , gram-negative , rod-shaped , enteri c bacterium . Edema : Presenc e o f

abnormall y larg e amount s o f flui di n th e intercellula r tissu e space s o f

th e body ; usuall y applie dt o th e demonstrabl e accumula

tio n o f excessiv e flui di n th e subcutaneou s tissues . Electromyographic : Pertainin g t o electromyogra

phy , th e recordin g an dstud y o f th e intrinsi c electrica l propertie s o f

skeleta l muscle . A- 5P.7 3

Electro n microprobe : X-ra y metho di n whic h electron s fro mahot-filamen t sourc e ar e acceler

ate delectrostatically , the n focuse dt o a n ex tremel y smal l poin t

o n th e surfac e o f

aspecime n b y a n electromagneti c lens ; metho dfo r non destructiv e analysi s o f

chemica l compositio n b y measuremen t

o f resultin g backscatte r

o r othe r phenomena . Electronegativity : Electro-affinity . Encephalitis : Inflammatio n o f th e brain . Encephalopathy : An y degenerativ e diseas e o f th e brain . Epidemiology : Stud y o f th e distributio n an ddeter

minant s o f

diseas e i n huma n populatio n groups . Epinephrine : Hormon e secrete db y adrena l medull a tha t act s t o increas e bloo dpressur e b y mean s o f stimulatio n o f

hear t actio n an dconstrictio n o f pe riphera l bloo dvessels . Episodal : Adjectiv e i n curren t usag e tha t

denote s a n ai r pollutio n episode ; tha t i s th e occurrenc e o f short-term , pea k

ai r pollutan t

concentration s o f crisi s proportions . Epithelial : Pertainin g t o o r compose do f

epithelium ; tha t is , coverin g o f

externa l o r

interna l bod y sur faces , includin g lining s o f vessel s an dothe r

smal l cavities , compose do f

cell s joine dtogethe r

wit h cementin g substances . Equilibriu mvapo r

pressure : Vapo r

pressur e o f

a syste mi n whic htw o o r

mor e phase s o f

asubstanc e coexis t i n equilibrium . Erosion : Movemen t

o f soi l o r roc k fro mon e poin t

t o anothe r b y th e actio n o f

th e sea , runnin g water , movin g ice , precipitation , o r wind . Erythrocyt e porphyrin : Se e Fre e erythrocyt e pro toporphyrin . Erythrocyt e protoporphyrin : Se e Fre e Erythrocyt e portoporphyrin . Erythrocytes : Re dbloo dcells . Erythropoiesis : Formatio n o f re dbloo dcells . Ethylenediaminetetraaceti c aci d(EDTA) : Use di n th e formo f

calcium-disodiu msal t a s achelatin g agen t t o comple x wit hlea dan dothe r metal s an d remov e the mfro mth e bod y b y urinar y excretion . Evaporation : Physica l proces s b y whic haliqui do r soli di s transforme dt o th e gaseou s state ; opposit e o f condensation . Evoked-respons e technique : A techniqu e widel y use di n electrophysiolog y i n whic hastimulu s (e.g. , electri c shock , ligh t flash , click ) i s applie d peripherall y t o th e electrod e use dt o detec t th e response . Exencephaly : A developmenta l anomal y charac

terize db y a n imperfec t cranium , th e brai n lyin g outsid e th e skull . Exposur e level : Concentratio n o f acontaminan t

t o whic hth e populatio n i n questio n i s exposed . Exudate : Material , suc ha s fluid , cells , o r cellula r debris , tha t

ha s escape dfro mbloo dvessel s an d ha s bee n deposite di n tissue s o r o n tissu e surfaces , usuall y a s aresul t

o f inflammation ; contain s hig h conten t o f protein , cells , o r

soli dmaterial s derive dfro mcells . Fallout : I n ai r

pollution , particulat e matte r tha t fall s t o th e surfac e o f

th e eart hthroug hth e actio n o f gravity ; apassiv e phenomeno n unrelate dt o at r mospheri c o r

mechanica l motion . Fancon i syndrome : I n thi s document , th e tria do f glycosuria , hyperaminoaciduria , an dhy r pophosphatemi ai n th e presenc e o f hy 7 perphosphaturi atha t

i s associate dwithinjur y t o proxima l rena l tubula r

cells . Flinch/jum p thresholds : Behaviora l testin g pro cedur e use dt o measur e pai n threshol db y measuri

n g sensitivit y t o shock . Th e shoc k intensit y at whic hanimal s first

flinc han dfirst

jum p in respons e t o foo t

shoc k i s recorded . Flux : Rat e o f

flo w o f som e quantity , ofte n use di n referenc e t o som e formo f energy ; als o calle d transport . Fornix : Genera l ter mfo r a n archlik e structur e o r th e vaultlik e spac e create db y suc hastructure ; forni x o f cerebrum—efferen t

pathwa y o f

th e hippocarri

j pus . Fre e erythrocyt e porphyri n (FED) : Se e Fre e erythrocyt e protoporphyrin . Fre e erythrocyt e protoporphyri n (FEP) : Intermedit

at e i n th e biosynthesi s o f heme ; specifically , th e immediat e precurso r

t o hem e synthesi s i n whic h on e ato mo f

iro n i s inserte dint o th e pro toporphyri n nucleu s t o for mheme . Use din

terchangeabl y wit herythrocyt e protoporphyri n an derythrocyt e porphyrin . Fugitiv e dust : Dus t

tha t escape s fro mindustria l pro * cesses , soi l surfaces , roadways , etc. ; dus t tha t can no t b e containe db y ai r

pollutio n contro l prac tices . /3-Galactosidase : Enzym e tha t hydrolyze s galac r toside s (compound s containin g asuga r an danon suga r component ) t o produc e D-galactose . Galena : Lea dsulfid e ore . Ganglia : Plura l o f

ganglion , agenera l ter mfo r a grou p o f nerv e cel l bodie s locate doutsid e th e centra l nervou s system ; basa l ganglia—masse s o f gra y matte r

i n th e cerebra l hemisphere . A- 6Gastrointestina l mucosa : Mucou s membran e o f th e stomac han dintestine . Geometri c mean : An estimat e o f th e media n o f

alog

norma l distribution , calculate da s th e anti

logarith mo f

th e mea n o f

th e logarithm s o f

th e ob

servations . Geometri c standar ddeviation : A measur e o f disper

sio n fo r alognorma l distribution ; it i s th e anti

logarith mo f

th e standar ddeviatio n o f th e logarithm s o f

th e observations . (Als o know n a s standar dgeometri c deviation. ) Glacier : Mas s o f

lan dic e flowin g slowl y (a t presen t o r in th e past ) fro ma n accumulatio n are at o an are ao f ablation . Glacie r ice : An y ic e tha t

i s o r onc e wa s par t

o f a glacier . Glomerula r

filtration : Filtratio n o f plasm ab y th e glomerul i o f

th e kidne y tha t

remove s fluids , electrolytes ; glucose , amin o acids , an dothe r smal l molecules ; 8 0 t o 8 5 percen t o f wate r an d virtuall y al l o f

th e othe r

substance s ar e reab

sorbe db y th e proxima l tubules . Glomerulus : Anatomica l ter mdesignatin g atuf t o r cluste r o f bloo dvessel s o r

nerves ; ofte n use d alon e t o designat e rena l glomeruli , whic har e coil s o f bloo dvessels , on e projectin g int o th e ex pande den do r

capsul e o f

eac ho f th e uriniferou s tubule s o f

th e kidney . Glucose-6-phosphat e dehydrogenase : Enzym e im

portan t in maintenanc e o f

adequat e concentra tion s o f reduce dglutathion e in re dbloo dcells . Deficienc y o f

thi s enzym e i s inherite da s asex linke dtrait ; i t

mediate s th e reaction , D

glucose-6-phosphat e + NAD P = D-glucono-8

- lacton e 6-phosphat e + NADPH 2 . /3-Glucuronidase : Enzym e tha t mediate s th e hy

drolysi s o f

natura l an dsyntheti c glucuronides ; yield s /3-D-glucuronat e a s aproduct . Glutamat e dehydrogenase : Enzym e tha t mediate s th e remova l o f

hydroge n atom(s ) fro mglutamate , th e sal t o r este r o f glutami c acid , whic hi s adicar

boxyli c amin o acid . Glutathione : Tripeptid e tha t serve s a s acoenzym e an dact s a s arespirator y carrie r o f oxygen . Reduce dglutathion e (GSH ) i s presen t i n re dcell s an di s associate dwit hglucose-6-phosphat e dehydrogenas e an dreduce dnicotinamid e adenin e dinucleotid e phosphat e i n maintenanc e o f re dcel l integrity . Glycosuria : Presenc e i n th e urin e o f glucose , asim

pl e suga r forme dfro mmor e comple x sugar s an d normall y retaine din th e bod y a s asourc e o f energy . Grignar dprocess : A relativel y commo n syntheti c procedur e fo r

th e preparatio n o f

organometalli c compound s fro man organomaghesiu mprecursor . Groundwater : Al l subsurfac e water , especiall y tha t par t tha t i s i n th e zon e o f

saturation . Half-life : Tim e require dfo r asyste mdecayin g at

a n exponentia l rat e (suc ha s a n elemen t in radioac

tiv e disintegration ) t o b e reduce dt o one-hal f it s initia l size , intensity , o r numerica l amount . Haze : Fin e dus t

o r sal t particle s disperse dthroug ha portio n o f

th e atmosphere ; th e particle s ar e s o smal l the y canno t

b e fel t o r individuall y see n with th e nake deye , bu t

the y diminis hhorizonta l visibilit y an dgiv e th e atmospher e acharacteristi c opalescen t

appearanc e tha t

subdue s al l colors . Hematofluorometer : Commerciall y availabl e porta bl e spectrofluoromete r use dt o measur e erythrocyt e protoporphyri n (porphyrin ) directly ; in wid e us e in lea dscreenin g programs . Hematopoiesis : Formatio n an ddevelopmen t o f bloo dcells . Hematopoieti c system : Syste mo f cell s in bon e mar row , spleen , an dlymp hnode s concerne dwithfor

matio n o f

cellula r element s o f

th e blood . Hemin : Crystallin e chlorid e o f heme , C3 4 H 33 N 4 0 4 FeCl . Heparin : Mucopolysaccharid e aci doccurrin g naturall y in variou s tissues , especiall y th e live r an dlungs ; sodiu mheparin , amixtur e obtaine d fro manima l tissues , i s an anticoagulan t use din vivo an din vitro. High-volum e sampler : Devic e fo r takin g alarg e sampl e o f

ai r i n aminima l spa n o f

time , routinel y abou t 200 0 m 3 /2 4 h r

(1.3 8 m 3 /min) , o r

eve n a s hig h a s 288 0 m 3 /2 4 h r

( 2 m 3 /min) . Hippocampus : Curve delevatio n in th e inferio r hor n o f th e latera l ventricl e o f th e brain ; importan t functiona l componen t

o f th e limbi c system , th e syste mcontrollin g autonomi c function s an dcer tai n aspect s o f

emotio n an dbehavior . Histidin e residue : On e o f th e naturall y occurrin g peptid e linkage s in aprotein , containin g th e chemica l group , imidazole :

H C = C



### II N N H 

# V C H A- 7P.7 5

Homovanilli c acid : A methylate dmetabolit e o f hy

droxytyramine :

CH 3 0 H O CH 2 -COO H Hydrocephalus : Conditio n characterize db y abnor

ma l accumulatio n o f

flui din th e crania l vault , ac companie db y enlargemen t o f th e head , promi

nenc e o f th e forehead , atroph y o f th e brain , men ta l deterioration , an dconvulsions . Hyperactivity : Abnormall y increase dactivity . Developmenta l hyperactivit y o f childre n i s characterize db y constan t motion—exploring , ex perimenting , etc.—an di s usuall y accompanie db y distractibilit y an dlo w toleranc e fo r frustration . I t usuall y abate s durin g adolescence . Ma y resul t fro mbrai n damag e o r

psychoses . Hyperkinesia : Abnormall y increase dmoto r functio n o r activity ; see Hyperactivity . Hyperkinetic : Characterize db y abnormall y in

crease dmuscula r

movement . Hyperkinetic-aggressiv e behavio r disorder : A dis

orde r characterize db y overactivity , restlessness , distractibility , an dshor t attentio n span . Hyperphosphaturia : Above-norma l amount s o f phosphat e compound s i n th e urine . Hyperuricemia : Abnorma l amount s o f uri c aci di n th e blood . Hypochromi c anemia : A conditio n characterize db y adisproportionat e reductio n o f re dcel l hemoglobin , compare dwit hth e volum e o f packe dcells . Hypophosphatemia : Abnormall y decrease damoun t o f phosphate s in th e blood . Hypothalamus : Portio n o f th e diencephalo n tha t form s th e floo r

an dpar t

o f th e latera l wal l o f

th e thir dventricl e o f

th e brain . Imidazol e group : Se e Histidin e residue . Impactor : Genera l ter mfo r instrument s tha t

sampl e atmospheri c particle s b y impaction ; suc hdevice s consis t o f ahousin g tha t

constrain s th e ai r

flo w pas t asensitize dsamplin g plate . Impinger : Devic e use dt o sampl e dus t o r othe r parti

cle s i n th e air ; draw s i n ameasure dvolum e o f ai r an ddirect s i t

throug haje t

t o impac t

o n awette d surface . In situ: I n th e origina l location . Interstitia l fibrosis : A progressiv e formatio n o f fibrou s tissu e i n th e interstice s i n an y structure ; i n th e lungs , i t

reduce s aeratio n o f

th e blood . In vitro: Outsid e th e livin g organism . In vivo: Withi n th e livin g organism . Iro n deficiency : A deficienc y o f iron-containin g food s i n th e die t

suc htha t

no t enoug hiro n i s availabl e fo r

incorporatio n int o newl y forme d hemoglobin ; iro n deficienc y withi n th e bod y ma y als o resul t

fro mpoo r

intestina l absorptio n o f iro n i n spit e o f

adietar y sufficiency . Ischemia : Deficienc y o f bloo di n apart , cause db y functiona l constrictio n o r actua l obstructio n o f

a bloo dvessel . Ischemic : Pertainin g to , o r affecte dwith , ischemia . Isocortex : Neopallium ; tha t portio n o f

th e cerebra l corte x showin g stratificatio n an dorganizatio n characteristi c o f

th e mos t

highl y evolve dtyp e o f cerebra l tissue . Isokineti c sampling : Takin g asampl e o f ai r withou t changin g th e spee do r

directio n o f

th e ai r a s it en ter s th e sampler . Jiggl e platform : Apparatu s use di n behaviora l test in g t o measur e an animal' s activity . Generall y consist s o f

aspring-loade dplatfor mequippe d withadetecto r

fo r measurin g movement . a-Ketoglutarate : Sal t

o f a-ketoglutari c acid , a dibasi c ket o aci doccurrin g a s a n intermediat e i n carbohydrat e (Kreb s cycle ) an dprotei n metabol

ism . Kilocalorie : Uni t

o f hea t energ y equa l t o 100 0 calo

ries ; als o know n a s larg e calorie . Lacti c aci ddehydrogenas e (LDH) : Catalyze s reduc

tio n o f pyruvi c aci db y reduce dnicotinamid e adenin e dinucleotide ; prevent s buildu p o f pyru vat e i n anaerobi c glycolysis . Leached : Subjecte dt o th e actio n o f percolatin g wate r o r othe r liqui dtha t

remove s th e solubl e substances . Lea dparticles : Lead-containin g particles . Lea dpoisonin g (syn . lea dintoxication , plumbism , saturnism) : A diseas e conditio n reflectin g th e ad

vers e effect s o f

th e absorptio n o f

lea dint o th e system . Lea dsubacetat e (syn . lea dmonosubacetate , monobasi c lea dacetate) : Pb(C 2 H 3 0 2 ) 2 «2P b (OH) 2 . Learnin g paradigm : A particula r se t o f experimenta l condition s use dt o stud y learning . Ligand : A molecule , ion , o r ato mtha t

i s attache dt o th e centra l ato mo f

acoordinatio n compound , a chelate , o r

othe r complex . Lin e source : Consist s o f anumbe r

o f poin t source s arrange di n astraigh t

line , usuall y acros s win d (se e Poin t

source) . A- 8P.7 6

Lipoamid e dehydrogenase : Trivia l nam e fo r lipoamid e oxidoreductase ; enzym e catalyzin g th e reaction , NA D + dihydro-lipoamid e = NADH 2 + oxidize dlipoamide . Lithosphere : Th e rigi doute r crus t o f roc k o n th e earth , abou t

8 0 k mdeep ; mor e recently , wit h developmen t

o f plat e tectonic s theory , th e oute r 100 k mo f th e earth' s surface . Lognorma l distribution : A variabl e whos e logarithm s follo w anorma l distributirin . Lumen : Th e cavit y o r channe l withi n atubula r organ ; in thi s document , intestinal . Lymphocyte : Mononuclea r leukocyt e ( awhit e bloo d cell ) wit hadeepl y stainin g nucleu s containin g dens e chromatin ; chiefl y aproduc t o f lymphoi d tissue , it participate s i n humora l an dcell-medi

ate dimmunity . Lysosome : Submicroscopi c organelle , foun db y electro n microscop e i n man y type s o f cells , tha t contain s variou s hydrolyti c enzyme s an di s nor mall y involve din localize dintracellula r diges

tion . a-Mannosidase : Enzym e tha t catalyze s th e hy

drolysi s o f

a-D-mannosid e t o an aocoho l an dD

mannose , asimpl e sugar . Mas s media n diamete r

(MMD) : Geometri c media n siz e o f adistributio n o f

particles , base do n weight . Mas s media n equivalen t diamete r

(MMED) : Conve

nien t paramete r

fo r characterizin g airborn e par ticulates ; divide s th e tota l mas s o f aeroso l parti

cle s int o tw o equa l parts : hal f th e mas s reside s in a relativel y smalle r

numbe r o f particle s large r

tha n thi s media n siz e an dhal f reside s i n arelativel y large r numbe r

o f particle s havin g diameter s belo w thi s media n size . Maze : Syste mo f

intersectin g path s use di n test s o f intelligenc e an dlearnin g i n experimenta l animals . McCarth y Scale s o f

Intelligence : A standardize din

tellectua l assessmen t

instrumen t

(appropriat e fo r age s 2. 5 t o 8. 5 yr) , consistin g o f five subtest s yieldin g individua l score s in (1 ) verbal , (2 ) per ceptual-performance , (3 ) quantitative , (4 ) memo ry , an d(5 ) motor , a s wel l a s yieldin g agenera l cognitiv e inde x comparabl e t o a n intellectua l quotien t (I.Q. ) score . Mean : Use dsynonymousl y wit hth e arithmeti c mean ; tha t

is , th e su mo f

th e observation s divide d b y th e sampl e size . Meninges : Thre e membrane s tha t envelop e th e brai n an dspina l cord ; th e dur amater , pi amater , an d arachnoid . Messenge r RN A (mRNA) : Linea r polyme r

o f nucleotide s tha t

i s transcribe dfro man dcomple

mentar y t o asingl e stran do f DNA ; carrie s infor

matio n fo r

protei n synthesi s t o th e ribosomes . Metabolites : En dproduct s o f metaboli c processe s tha t transfor mon e compoun dint o anothe r i n liv

in g cells . Microcyti c anemia : Conditio n i n whic hth e majorit y o f th e re dcell s ar e smalle r tha n normal . Micromelia : Developmenta l anomal y characterize d b y abnorma l smallnes s o r shortnes s o f

th e limbs . Microsome : On e o f

th e fine r

granula r

element s o f protoplasm ; par t

o f th e endoplasmi c reticulum , sit e o f variou s metaboli c an dsyntheti c processe s includin g incorporatio n o f amin o acid s int o pro teins . Mist : Microscopi c an dmor e o r les s hygroscopi c wate r droplet s suspende din th e atmosphere . Relativ e humidit y whe n mis t i s presen t

i s ofte n les s tha n 9 5 percent . Mitochondria : Smal l organelle s foun di n th e cytoplas mo f

cells ; principa l site s o f

generatio n o f energy , the y contai n enzyme s o f th e Kreb s an d fatt y aci dcycle s an dth e respirator y pathway . Mobilizabl e lead : Th e fractio n o f th e tota l lea dcon ten t o f th e bod y tha t

ca n b e remove db y chelatin g agents . Molal : Containin g on e mol e o r on e gra mmolecula r weigh t i n 100 0 gram s ( 1 kg ) o f solute . Molar : Containin g on e mol e o r on e gra mmolecula r weigh t o f solut e in 100 0 ml ( 1 liter ) o f solution . Mole : Tha t

amoun t o f chemica l compoun dwhos e mas s in gram s i s equivalen t t o it s formul amass , i.e. , mas s numericall y equa l t o th e molecula r weigh t an dmos t

frequentl y expresse da s th e gra m molecula r

weigh t (th e weigh t

o f on e mol e ex presse di n grams) . Midbrain : Mesencephalon ; portion s o f th e adul t brai n derive dfro mth e embryoni c midbrain . Miniatur e end-plat e potential s (MEPP's) : Smal l po tentia l change s in th e neighborhoo do f th e en d plat e representin g th e respons e o f th e membran e t o releas e o f

acetylcholin e i n quantitie s insuffi

cien t t o depolariz e th e membran e t o threshol d levels . Monoamine : Organi c compoun dt o whic ha n amin e (-NH 2 group ) i s attached ; e.g. , serotonin . Monamin e oxidase : Flavoprotei n tha t catalyze s th e aerobi c oxidatio n o f

physiologica l amine s t o th e correspondin g aldehyde s an dammonia ; act s upo n serotonin , anervou s syste mregulator , t o yiel d5

- hydroxy-indolealdehyde . A- 9P.7 7



### Monominergic : Stimulated , activated , or transmit

te db y monoamines ; applie dt o nerv e fiber s tha t liberat e monoamine s a

t asynaps e whe

n anerv e impuls e passes . Moto r skills : Skille dmovement s that depen don th e integrity o

f th e nervou s syste

mfo r control . Mutagenicity : Property o f bein g abl e t o induc e geneti c mutation , i.e. , apermanent , transmissabl e chang e i n th e geneti c material . Myelopathy : Patholog y o f th e muscl e fibers . Myxedema : Nonpittin g edem acharacterize db y dry , wax y typ e o f swelling , wit

habnorma l deposit s o

f mucin i n th e skin andothe r

tissues ; associate d wit hhypothyroidism . Nasopharynx : Th e par t

of th e pharyn x tha t

lie s abov e th e level o

f th e sof t palate ; th e pharyn x bein g th e muscular , membranou s sa c between th e mouth , th e nares , an dth e esophagus . Nationa l Air

Surveillanc e Network s (NASN) : Net

work s of monitorin g station s fo

r samplin g ai r

t o determin e exten t

o f pollution . Establishe djointl y b y Federa l andstate governments . Neoplasm : A

n aberran t

ne w growt ho f abnorma l cell s o r tissu e i n whichth e growt

hi s uncontrolla

bl e an dprogressive . Nephritis : Inflammatio n o f th e kidney . Nephropathy : Diseas e o

f th e kidneys . Nerv e conduction : Passag e o f anerv e impuls e manifeste db

y a n electri c impuls e that

travel s alon g th e nerve . Neuropathy : Functiona l disturbance s and/o r pathological change s i

n th e periphera l nervou s system ; affect s th e neuron s (nerv e cells , includin g cel l body , axon , an ddendrites) . Neuropil : Dens e feltwor

k o f interwove n cytoplasmi c processe s o

f nerv e cell s an do

f neuroglial cell s i

n th e centra l nervou s syste

mandi n som e part s o f th e periphera l nervou s system . Nictitatin g membrane : Thi n membrane , o r inner or thir deyelid , present

i n man y animals ; capabl e o

f bein g draw n acros s th e eyeball , a s fo r protection . Norepinephrine : Hormon e secrete dby neurons ; act s a s atransmitte r

substanc e a

t th e periphera l sympatheti c nerv e ending s an dprobabl y i n certai n synapse s i n th e centra l nervou s system . Norma l distributio n (Gaussian distribution) : Funda

menta l frequenc y distributio n of statistica l analysis . A continuou s variate , x , i s sai dt o hav e anorma l distributio n o r t o b e normall y dis

tribute di f i t possesse s adensit

y function , f(x) , that satisfie dth e equation : f (x) =_U-( X - ^ W (-oo< X <oc) , cr27 r' 

### where fi i s th e arithmeti c mea n (o r first moment ) an do - i s th e standar ddeviation . Abou t two-third s o f th e tota l are aunde r

th e curv e i s include dbe

tween x = fi-a andx = fi + o \ Normal population : Collectio n o f quantitie s havin g anorma l distribution . Normoblast : Nucleate dpercurso r cel l intermediat e i n th e formatio n o

f erythrocytes . Nuclea r inclusio n bodies : Round , oval , o r ir

regularl y shape dbodie s appearin g i n th e nucle i o

f cells . Nucleus : Small mas s o

f differentiate dprotoplas m ric hi n nucleoprotein s an dsurrounde db y a membrane ; foundi

n mos t animal an dplan t

cells ; contain s chromosome s andfunction s i n metabol

ism , growth , an dreproduction . One-wa y avoidanc e tasks : Se

e Avoidanc e task . Optical emissio n spectrography : Analytical metho d i n whichth e sampl e i s vaporize dan ddecom

posed , an dth e constituen t element s excite db

y a n electrica l ar c o r

ahighvoltag e spark . Th e ligh t emitte da s aconsequenc e o f th e excitatio n passe s throug haspectrograp han dth e resultin g spectru mi s recorde dphotographically . Paraplegia : Paralysi s o

f th e leg s an dlower

par t of th e body . Parenchyma : Genera l ter mt o designat e functional element s o

f a n organ a s distinguishe dfro mit s framework , o r

stroma . Particl e eddy diffusivity : Th e diffusion o f particle s b y eddie s i n aturbulen t

flow . D-penicillamine : Produc t of penicillin ; whitis h crystallin e powder

useda s ametal complexin g agent t o remov e exces s metal s fro mth e body . Peptidergic : Stimulated , activated , o r transmitte db

y peptides ; applie dt o thos e nerv e fiber s that liber

at e peptide s a

t asynaps e whe

n anerv e impuls e passes . Photolysis : Chemical decompositio n b y th e actio n o

f light . Phreni c nerve : Arisin g fro mth e third , fourth , an d fifthcervical segment s o f th e spinal cord , th e nerv e tha t innervate s th e diaphragm . Pica : Habitua l ingestio n o f nonfoo ditems . Pinna : Projectin g par t

of th e ea r lying outsid e th e head . Plumbism : Leadpoisoning ; saturnism . A-1 0Poin t

source : A singl e isolate dstationar y sourc e o f pollution . Polarography : A n electroanalytica l techniqu e in whic hth e curren t

throug ha n electrolysi s cel l i s measure da s afunctio n o f th e applie dpotential . Polyneuropathy : Diseas e tha t involve s severa l nerves . Polysomes : Comple x o f ribosome s boun dtogethe r b y asingl e messenge r

ribonuclei c aci d(mRNA ) molecule . Als o know n a s polyribosome . Porphobilinoge n (PBG) : Intermediat e i n th e bio

synthesi s o f

hem e tha t

doe s no t accumulat e unde r norma l circumstances . Porphyrin : An y on e o f

agrou p o f

iron-fre e o r

mag nesium-fre e cycli c tetrapyrrol e derivative s tha t occu r universall y i n protoplasm . The y formth e basi s o f th e respirator y pigments , suc ha s cytochrome s an dchlorophyll , o f animal s an d plants . Precipitation : An y o r

al l form s o f

wate r particles , liqui do r solid , tha t

fal l fro mth e atmospher e an d reac hth e ground . Prevailin g win ddirection : Win ddirectio n mos t fre

quentl y observe ddurin g agive n period . Primar y smelting : Extractio n o f meta l fro more . Promotiona l energy : Energ y require dt o promot e an electro n fro mit s fre e ato mgroun dstat e t o th e hy

bridizatio n stat e require dfo r bonding . Protoporphyri n (PP) : Porphyri n tha t i s th e protein

fre e precurso r

t o hemoglobin , myoglobin , catalase , an dcertai n respirator y pigments . Protoporphyri n IX : A n isome r o f protoporphyrin . Proxima l convolute dtubules : Convolute dportio n o f th e vertebrat e nephro n (functiona l uni t o f th e kidney ) lyin g betwee n Bowman' s capsul e an dth e loo p o f Henle ; function s i n resorptio n o f sugar , N a+ ,C1 , an dwater . Psychomotor : Pertainin g t o moto r effect s o f

cerebra l o r psychi c activity . Pyrimidine-5'-nucleotidase : Enzym e tha t mediate s hydrolysi s o f

pyrimidine-5'-phosphat e t o yeil din

organi c phosphoru s an dth e correspondin g pyrimidin e nucleoside . Pyrrole : Heterocycli c rin g compound , consistin g o f fou r carbo n atoms , on e nitroge n atom , an dfive hydroge n atoms , tha t i s acomponen t

o f chlorophyll , hemin , an dman y othe r importan t naturall y occurrin g substances . Pyruvate : Sal t

o f pyruvi c acid , an importan t inter

mediat e i n carbohydrat e (Kreb s cycle ) an dpro tei n metabolism . Reentrainment : Resuspensio n o f particulat e matter , especiall y dust , i n th e ambien t air ; se e tex t

dicus

sio n o f resuspension . Referenc e method : I n thi s document , th e official , ac cepte dmetho dfo r

samplin g an danalysi s o f an elemen t o r compound ; metho dt o whic hothe r method s ar e compare dfo r accurac y an dpreci

sion , and/o r

fo r reportin g o f

data . Relativ e humidity : Dimensionles s rati o o f actua l vapo r pressur e o f

th e ai r t o th e saturatio n vapo r pressure ; usuall y expresse da s percent . Rena l insufficiency : Stat e i n whic hth e kidney s ar e unabl e t o remov e asufficien t proportio n o f

th e effete , o r spent , matte r

o f th e blood . Reticulocytosis : Increas e i n th e numbe r o f reticulocyte s (youn g re dbloo dcell s showin g basophili c networ k

unde r vita l staining ) i n th e pe riphera l blood . Ribonuclei c aci d(RNA) : Nuclei c aci di n th e formo f alinea r polymer , usuall y asingl e strand , com pose do f

repeatin g unit s o f

nucleotide s (th e organi c bases ; adenine , cytosine , guanine , an d uracil ) conjugate dt o ribos e an dkep t in sequenc e b y phosphodieste r

bonds . Involve din

tracellularl y in protei n synthesis . Ribosomes : Comple x smal l particle s in th e livin g cell , compose do f

variou s protein s an dthre e molecules.o f

RNA ; sit e o f

synthesi s o f

proteins . Samplin g error : Differenc e betwee n ameasure d valu e an dth e tru e valu e tha t result s fro msam plin g technique s an dprocedures . Samplin g train : Pollutan t collectin g devic e consist

in g o f aserie s o f

component s throug hwhic ha n ai r strea mpasses . Component s usuall y includ e prefitter ; pipe s o r

ducts ; mean s fo r

measurin g ai r flow ; a n ai r

pump ; an dadetecto r

o r senso r tha t give s an immediat e readin g or acollecto r

i n whic hth e pollutan t

i s subsequentl y measured . Saturnism : Lea dpoisoning . Schwan n cell : On e o f

th e larg e nucleate dmasse s o f protoplas mlinin g th e inne r surfac e o f

th e neurilemma , amembran e wrappin g th e nerv e fiber. Secondar y smelting : Extractio n o f meta l fro mscra p an dsalvage . Sedimentation : Th e ac t o r proces s o f

depositio n o f sediment ; ca n refe r

(1 ) t o th e depositio n o f air

born e particulat e matte r o n asurfac e o r

(2 ) t o th e depositio n an daccumulatio n o f soli dmatte r

o n th e be do f

abod y o f

water . Seizure : Sudde n onse t

o r recurrenc e o f

adiseas e o r a n attack ; specifically , a n epilepti c attack , o r con vulsion . A-l lP.7 9

Septum-fronta l forebrain : Describe s anatomica l connection s i n th e brai n betwee n th e septa l are a an dth e forebrain . Sequela : An y lesio n o r affectio n tha t

follow s o r

i s cause db y a n attac k

o f disease . Serotonin : A vasoconstrictor , 5-hydroxytryptamine , foun din seru man dman y bod y tissues , includin g th e intestina l mucosa , pinea l body , an dcentra l nervou s system , especiall y th e hypothalamus , midbrain , basa l ganglia , an dspina l cord ; believe d t o b e aneurotransmitte r tha t play s aregulator y rol e i n th e centra l nervou s system . Seru mglutamic-oxaloaceti c transaminas e (SGOT) : Enzym e tha t

transfer s a n amin o grou p fro mL

glutami c aci dt o oxaloaceti c acid , formin g 8

- ketoglutari c aci dplu s L-asparti c acid . Ox

aloaceti c an d8-ketoglutari c acid s ar e bot hmajo r intermediate s i n th e citri c aci dcycl e (Kreb s cy cle) , th e energy-generatin g cycle . Seru mglutamic-pyruvi c transaminas e (SGPT) : Enzym e tha t

transfer s an amin o grou p fro mL

glutami c aci dt o pyruvi c acid , formin g 8

- ketoglutari c aci dplu s L-alanine . 8-Ketoglutari c aci di s amajo r

intermediat e i n th e Kreb s cycle , an dpyruvi c aci di s th e immediat e precurso r o f acetylcoenzym e A , whic hcombine s wit hox aloaceti c aci dt o formcitri c aci din th e citri c aci d cycl e (Kreb s cycle) . Shuttl e box : Two-compartmen t chambe r

use din anima l behavior ; th e movemen t fro mon e com partmen t t o th e othe r

i s th e behavio r

tha t i s studied . Sore t band : Ban di n th e viole t en do f th e spectru mo f hemoglobin . Spin abifida : Developmenta l anomal y characterize d b y defectiv e closur e o f

th e bon y encasemen t

o f th e spina l cord . Stabilimeter : Devic e use dt o measur e a n animal' s ac tivit y b y measurin g vertica l movemen t o f th e floor . Stac k emissions : Effluent s release dint o th e at mospher e fro mth e exhaus t flu e o f abuilding ; usuall y refer s t o pollutant s bu t ca n refe r

t o stea m o r othe r nonpollutin g effluents . Standar ddeviation : A measur e o f dispersio n o r variation , usuall y take n a s th e squar e roo t o f th e variance . Standar dgeometri c deviation : Measur e o f disper

sio n o f value s abou t

ageometri c mean ; th e por tio n o f th e frequenc y distributio n tha t i s on e stan dar dgeometri c deviatio n t o eithe r sid e o f th e geometri c mea n account s fo r 6 8 percen t

o f th e tota l samples . Standar dnorma l deviation : Measur e o f dispersio n o f value s abou t

amea n value ; th e positiv e squar e roo t o f th e averag e o f

th e square s o f

th e in

dividua l deviation s fro mth e mean . Stanford-Bine t

I.Q . Test : A standardize dintellec

tua l assessmen t

instrumen t

(appropriat e fo r

age s 2 y r t o adult) , yieldin g agenera l intelligenc e quo tien t (I.Q. ) score . Stead y stat e exposure : Exposur e t o a n environmen

ta l pollutan t

whos e concentratio n remain s con stan t fo r aperio do f

time . Stoichiometry : Numerica l relationshi p o f element s an dcompound s a s reactant s an dproduct s in chemica l reactions . Stratosphere : Atmospheri c shel l abou t 5 5 k mdee p tha t begin s wher e th e tropospher e ends , a t 1 0 t o 2 0 k mfro mth e earth' s surface . Striatum : Corpu s striatum ; subcortica l mas s o f gra y an dwhit e substanc e i n fron t o f an dlatera l t o th e thalamu s i n eac hcerebra l hemisphere . Stroma : Supportin g tissu e o r matri x o f

a n organ , a s distinquishe dfro mit s functiona l element , o r parenchyma . Subclinica l lea dpoisoning : Toxi c effect s o f lea dtha t d o no t produc e clinicall y discernibl e signs . Succinate : Sal t

o f succini c acid , importan t inter

mediat e in carbohydrat e (Kreb s cycle ) an dpro tei n metabolism . Succinoxidase : Comple x enzym e system , containin g succini c dehydrogenas e an dcytochromes , tha t catalyze s th e conversio n o f succinat e an dmolecu

la r oxyge n t o fumarat e ( aKreb s cycl e intermedi

ate) . Succiny l coenzym e A : COOH(CH 2 ) 2 COOH-S-CoA ; compoun dforme dfro msuccini c aci dan d coenzym e A i n th e citri c aci dcycl e (Kreb s cycle) . I t provide s fre e energ y fo r th e synthesi s o f

a molecul e o f

AT P an dca n participat e in acylatin g reaction s fo r

th e introductio n o f

asucciny l group ; it als o participate s i n othe r metaboli c reactions , suc ha s th e synthesi s o f porphyrins . Sulfhydry l group : Th e -S H grou p occurrin g i n reduce dglutation e an di n cysteine . Superio r cervica l ganglion : A grou p o f nerv e cel l bodie s locate doutsid e th e centra l nervou s system , situate dnea r

th e cervix . Surfac e water : Al l bodie s o f wate r o n th e surfac e o f th e earth . Synapse : Regio n o f

contac t betwee n processe s o f

tw o adjacen t neurons . Synapti c uptake : Movemen t o f achemica l int o th e neuro n i n th e are ao f

th e synapse . A-1 2P.8 0

Synaptosoma l transport : Uptak e o f achemica l int o isolate dsynapses . Synergetic : Workin g together ; an agen t tha t work s synergisticall y withon e o r mor e othe r

agents . Synergisti c effects : Join t effect s o f

tw o o r mor e agents , suc ha s drug s tha t increas e eac hother' s effectivenes s whe n take n together . Telencephalon : Paire dcerebra l vesicles , fro mwhic h th e cerebra l hemisphere s ar e derived . Teratology : Scienc e tha t deal s wit habnorma l developmen t

o f th e fetu s an dcongenita l malfor

mations . Teratospermia : Presenc e o f malforme dspermatozo a i n th e semen . Temperatur e inversion : Laye r o f ai r in whic htem peratur e increase s withaltitude ; ver y littl e tur bulen t exchang e occur s withi n it . Termina l velocity : Se e Termina l fal l velocity . Termina l fal l velocit y (termina l velocity) : Particu

la r fallin g speed , fo r

an y give n objec t

movin g throug haflui dmediu mo f specifie dphysica l properties , a t

whic hth e dra g force s an dbuoyan t force s exerte db y th e flui do n th e objec t jus t equa l th e gravitationa l forc e actin g o n th e object , afte r whic hit fall s at constan t

spee dunles s i

t move s int o ai r layer s o f

differen t physica l properties . I n th e atmosphere , th e latte r effec t i s s o gradua l tha t object s suc ha s raindrops , whic hattai n termina l velocit y a t

grea t height s abov e th e surface , ma y b e regarde da s continuousl y adjustin g thei r speed s t o remai n at

al l time s essentiall y i n th e termina l fal l condition . Topography : (1 ) Genera l configuratio n o f asurface , includin g it s relief ; ma y b e alan do r water-bot

to msurface ; (2 ) natura l surfac e feature s o f a region , treate dcollectivel y a s t o form . Transaminases : Enzyme s tha t catalyz e th e transfe r o f a n amin o grou p o f

a n amin o aci dt o aket o aci d t o for manothe r

amin o acid ; als o know n a s aminotransferases . Transfe r RN A (tRNA) : Smalles t ribonuclei c aci d molecul e foun di n cells ; it s structur e i s comple

mentar y t o messenge r

RN A an dit

function s in transferrin g amin o acid s fro mthei r fre e stat e t o a growin g polypeptid e chain . Transformation : I n thi s document , change s in physi

ca l o r chemica l formo f

lead-containin g particle s o r compound s tha t

occu r withtim e an dspac e durin g atmospheri c an denvironmenta l residenc e and/o r transport . Translocation : Transfe r o f metabolites , nutritiv e materials , o r

othe r substance s fro mon e par t o f a plan t t o another . Transport : I n thi s document , movemen t o f lea dan d it s compound s fro mon e plac e t o anothe r i n th e environment . Transudation : Passag e o f seru mo r

othe r bod y flui d throug hamembran e o r tissu e surface ; ma y o r ma y no t b e th e resul t

o f inflammation . Troposphere : Th e atmospheri c shel l extendin g abou t 1 0 t o 2 0 k

mfro mth e earth' s surface . Trypa n Blue : A n acid , az o dy e use din vita l staining ; unde r norma l conditions , it

doe s no t

ente r mos t area s o f th e brai n fro mth e blood . Tumor : An y abnorma l mas s o f cell s resultin g fro m excessiv e cellula r

multiplication . Turbulence : Stat e o f

flui dflow i n whic hinstan

taneou s velocitie s exhibi t irregula r

an dap parentl y rando mfluctuation s s o that , in practice , onl y statistica l propertie s ca n b e recognize dan d analyzed ; turbulenc e ca n transpor t suspende d matte r at rate s fa r in exces s o f

rate s o f transpor t b y diffusio n an dconductio n i n alamina r flow . Two-wa y aviodanc e tasks : Se e Avoidanc e task . Tyrosine : Amin o aci d(p-hydroxyphenylalanine , CgHnOjN ) foun din mos t protein s an dsyn thesize dmetabolicall y fro mphenylalanine . I t i s a precurso r

o f dopamin e an do f

th e hormones , epinephrine , norepinephrine , an d triiodothyronine . Ultradia n rhythms : Biologica l rhyth mwit hafre

quenc y highe r

tha n circadia n (2 4 hr) . Uncertainty : Standar ddeviatio n o f asufficientl y larg e numbe r

o f measurement s o f

th e sam e quan tit y b y th e sam e instrumen t o r methods ; th e non correctabl e inaccurac y o f th e instrument . Upwind : Towar dth e directio n fro mwhic hth e win d i s flowing ; counte r

t o th e wind . Urobilinogen : Colorles s compoun dforme di n th e in

testin e b y th e reductio n o f bilirubi n ( abil e pig

men t tha t i s abreakdow n produc t o f heme) ; som e i s excrete di n th e fece s wher e i t i s oxidize dt o urobilin ; som e i s reabsorbe dan dreexcrete din th e bil e (a s bilirubin ) o r

in th e urine . Uroporphyrin : An y o f

severa l isomeric , metal-fre e porphyrins , occurrin g i n smal l quantitie s i n nor ma l urin e an dfeces . Vacuolization : Formatio n o f vacuoles , an y smal l space s o r cavitie s forme din th e protoplas mo f a cell . A-1 3P.8 1



### Vacutainers : Registere dtrademark o f seale dam pules , maintaine dunde r

aslight vacuuman dcon tainin g a n anticoagulant , int o whichbloo dsam ple s ma y b e draw n directly . Vanilly l mandeli c aci d(vanilmandeli c acid) : A ma jo r metabolit e o

f th e catechloamines ; use dt o asses s quantitativel y th e endogenou s productio n o f catecholamines . Variance : A measure o

f dispersio n o r

variatio n o

f a sampl e fro

mit s expecte dvalue . It i s usuall y calculate da s asu

mo f square ddeviation s abou t a mea n divide db

y th e sampl e size . Wechsler Intelligenc e Tes t

(WISC) : A standardize d intellectua l assessment

instrumen t

(appropriat e fo r age s 6 y r t o 1 6 y r 1 1 mo) , consistin g o

f 1 2 sub

test s designe dt o yiel dverba l an dperformanc e in

tellectua l scores . Wet deposition : Removal o

f particle s fro

mth e at mosphere vi aprecipitation ; rainout . Wind : Air motio n relativ e t o th e surfac e o f th e earth . Vertica l component s ar e relativel y small , especiall y near

th e surfac e o

f th e earth ; hence , th e termdenote s almos t

exclusivel y th e horizonta l component . WPPS I Test : A versio n of th e WIS C test , bu t

consist

ing o f 1 0 subtest s representin g adownwardexten sio n of th e WIS C appropriat e for younge r childre n (age s 4 t o 6. 5 yr) . Xenobiotics : Chemical s foreig n t o biologi c systems . X-ray diffractio n analysis : Analysi s o f th e crystal structur e o

f material s b

y passin g Xray s throug h themandregisterin g th e diffractio n (scattering ) imag e o f th e rays . X-ray powder

diffractio n techniques : Analytical technique s i

n whicha

n X-ray bea

mo f known wavelengt hstrike s afinely groun dpowder sam ple ; th e crystal plane s o

f th e powder

diffrac t th e bea man dthes e diffractio n line s ar e recorde don photographi c film. X-ray spectrography : Analytical metho demployin g a n X-ray spectromete r

(instrumen t

fo r producin g th e X-ray spectru mo

f amaterial andmeasurin g th e wavelength s o

f components ) that

i s equippe d wit hphotographi c o r

othe r recordin g apparatus . Zin c erythrocyt e porphyrin : Th e biochemicall y cor rec t for mfo r th e erythrocyt e protoporthyri n o r porphyri n that

i s elevate di

n leadexposure o r iro n deficienc y anemia . Usedinterchangeabl y i n thi s documen t

wit herythrocyt e porphyrin , erythrocyt e protoporthyrin , an dfree erythrocyt e porphyri n o r

protoporthyrin .

A-1 4P.8 2



## APPENDI X B PHYSICAL/CHEMICA L DAT A FO RLEA D COMPOUND S B. l DAT A TABLE S TABL E B-1 , PHYSICA L PROPERTIE S O F INORGANI C LEA D COMPOUNDS ' Compoun d Lea d Acetat e Azid e Bromat e Bromid e Carbonat e Carbonate , basi c Chlorid e Chlorobromid e Chromat e Chromate , basi c Cyamid e Fluorid e Fluorochlorid e Format e Hydrid e Hydroxid e lodat e Iodid e Nitrat e Nitrate , basi c Oxalat e Oxid e d i Oxid e Oxid e (red ) Phosphat e Sulfat e Sulfid e Sulfit e Thiocyanat e Abbreviations : a - aci d a l - alcoho l al k - alkal i d - decompose s exp l - explode s Formul a

P b Pb(C 2 H 3 0 2 ) 2 Pb(N 3 ) 2 Pb(Br0 3 ) 2 -H 2 0 PbBr 2 PbC0 3 2PbC0 3 -Pb(OH) 2 PbCI 2 PbCIB r PbCr0 4 PbCr0 4 -Pb O Pb(CN) 2 PbF 2 PbFC I Pb(CHO) 2 PbH 2 Pb(OH) 2 Pb(l0 3 ) 2 Pbl 2 Pb(N0 3 ) 2 Pb(OH)(N0 3 ) PbC 2 0 4 Pb O Pb0 2 Pb 3 0 4 Pb 3 (P0 4 ) 2 PbS0 4 Pb S PbS0 3 Pb(SCN) 2 gly c - glyco l i - insolubl e s - solubl e M.W . - molecula rweigh t S.G . - specifi cgravit y MP. - meltin g poin t M.W . 207.1 9 325.2 8 291.2 3 481.0 2 367.0 1 267.2 0 775.6 0 278.1 0 322.5 6 323.1 8 546.3 7 259.2 3 245.1 9 261.6 4 297.2 3 209.2 1 241.2 0 557.0 0 461.0 0 331.2 0 286.2 0 295.2 1 223.1 9 239.1 9 685.5 7 811.5 1 303.2 5 239.2 5 287.2 5 323.3 5 S.G . 11.35 3.2 5 — 5.5 3 6.6 6 6. 6 6.1 4 5.8 5 — 6.1 2 6.6 3

— 8.2 4 7.05 4.6 3 — — 6.15 5 6.1 6 4.5 3 5.9 3 5.2 8 9.5 3 9.37 5 9. 1 7 6. 2 7. 5 — 3.8 2 M.P .

327. 5 28 0 expl . d18 0 37 3 d31 5 d40 0 50 1 — 844 — — 85 5 60 1 d19 0 d d14 5 d30 0 40 2 d47 0 d18 0 d30 0 88 8 d29 0 d50 0 101 4 1170 111 4 d d19 0 Solubility , g/10 0 Col d wate r i 44. 3 0.02 3 1.3 8 0.844 1 0.0001 1 i 0.9 9 — 6x10- 6 i s i s 0.06 4 0.03 7 1. 6 — 0.015 5 0.001 2 0.06 3 37.6 5 19. 4 0.0001 6 0.001 7 i i 1.4x10- 5 0.0042 5 8.6x10- 5 i 0.0 5 Ho t

wate r i 2215 0 0.097 0 S i s 4.7110 0 d i 3.3410 0 — i i s — 0.108 1 2 0 — s i s 0.00 3 0.4 1 12 7 s — — 0.005 6 — i 0. 2 m l Othe r

solvent s s a sgly c — — s a sa.al k sHN0 3 ia l — sa.al k sa.al k sKC N sHN0 3 — ia l — sa.al k sHN0 3 s.al k s.al k s a s a s.al k s a s a . s.al k — s a s a s.al k



### B- lP.8 3

TABL E B-2 . TEMPERATUR E VARIATIO N O F TH E VAPO R PRESSURE S O F COMMO N LEA D COMPOUNDS * Nam e Lea d Lea d bromid e Lea d chlorid e Leadflourid e Lea d iodid e Lea d oxid e Lea d sulfid e Formul a P b PbBr 2 PbCI 2 PbF 2 Pbl 2 Pb O Pb S MP .

327. 4 37 3 50 1 85 5 40 2 89 0 111 4 1 m m

97 3 51 3 54 7 soli d 47 9 94 3 85 2 (solid ) 10m m

1162 61 0 64 8 90 4 57 1 1085 97 5 (solid ) Temperatur e " C

40m m 130 9 68 6 72 5 100 3 644 118 9 . 104 8 (solid ) 100m m

142 1 74 5 78 4 108 0 70 1 1265 110 8 (solid ) 400m m

163 0 85 6 89 3 121 9 80 7 1402 122 1 760m m

1744 91 4 95 4 129 3 87 2 1472 128 1 

### B.2 . TH E CHELAT E EFFEC T Th e stability constant s o

f chelate dcomplexe s ar e normall y several order s o f magnitud e higher

than thos e o f comparabl e monodentat e complexes ; thi s effec t i s calle dth e chelat e effec t andi s ver

y readil y explaine di

n term s o f kineti c considerations . A com pariso n o f th e bindin g o

f asingl e bidentat e ligan d wit hthat o f tw o molecule s o

f achemicall y simila

r monodentat e ligan dshow s that , fo r th e monodentat e case , th e proces s ca

n b e represente db

y th e equa tions : M + BF=^M- B (B-l )



### M- B + Br=^MB 2 

### (B-2 ) k d 

### Th e relate dexpression s fo r th e bidentat e cas e are : Th e overal l equilibriu mconstants , therefore , are :

K 

### '-k b 

### k d ; K 

### 2

- k 2 

### k4 

### Fo r agiven metal, M , andtw o ligands , B an dB-B , whichar e chemicall y similar , i t i s establishe dthat

k , an dk a

### hav e value s simila r t o eac hother , a s d o k 2 

### andk b 

### , k 4 

### andk d 

### ; eacho

f thes e pair s o

f term s repre sent s chemicall y simila

r processes . Th e origi n o

f th e chelat e effec

t lie s i n th e ver y larg e valu e o

f k 3 

### rela

tiv e t o that

o f kc 

### . Thi s come s abou t

becaus e k 3 

### repre sent s aunimolecula

r process , wherea s k c 

### i s a bimolecular

rat e constant . Consequently , K2 

### »K, . Thi s concep t

can , o f course , b e extende dto'poly

dentat e ligands ; i

n general , th e more extensiv e th e chelation , th e more stabl e th e meta l complex . Hence , on e woul danticipate , correctly , tha t poly

dentat e chelatin g agent s suc ha s penicillamin e o r EDT A ca n for mextremel y stabl e complexe s wit h meta l ions .

M + B-BF=^M-B- B (B-3 ) B. 3 REFERENCE S FO R APPENDI X B

M-B- B =*rv K )

L B y 1 . Handboo k o f Chemistr y an dPhysics . 56t hEd . R.C . Weas t (ed.) . Cleveland , Th e Chemica l Rubbe r Co . 1975 . (B-4 ) 2 . Stu.ll . D.R . Vapo r pressur e o f

pur e substances : Organi c com pounds . Ind . Eng . Chem . J9(4): 5 1 7-540 . 1947 .

B- 2

# APPENDI X C

ADDITIONA L STUDIE S O F ENVIRONMENTA L CONCENTRATION S O F LEA D Thi s collectio n o f

studie s i s intende dt o exten d an ddetai l th e genera l pictur e o f lea dconcentration s in th e environmen t

an di n proximit y t o identifie d majo r source s a s portraye din Chapte r 7 . Th e lis t

i s b y n o mean s all-inclusive , bu t i s intende dt o b e representativ e an dt o supplemen t th e dat acite din Chapte r 7 . C. l GENERA L CENTRATION S AMBIEN T AI RCON C.l . 1 Seven-Cit y Stud y A specia l lea dstud y (Seven-Cit y Study ) wa s con ducte dfo r

12-mont hperiod s betwee n 196 8 an d 197 1 i n Cincinnati , Lo s Angeles , Philadelphia , Houston , Ne w Yor k

City , Washington , D.C , an d Chicago . Sample s o f

ambien t ai r wer e analyze db y atomi c absorptio n spectroscopy . Th e monthl y averag e lea dconcentration s obtaine dar e sum marize din Tabl e C-1 . Thi s study , specificall y designe dt o measur e am bien t lea dconcentration s at avariet y o f

site s withi n eac ho f th e cities , incorporate dtechnique s tha t woul dprovid e th e mos t precis e measur e o f

ambien t lea dconcentration s available . A membran e filte r wa s use dinstea do f

aglas s filter , an dth e sample s wer e collecte dcontinuousl y ove r 2 t o 3 day s rathe r tha n collecte di n biweekl y 24-h r period s a s i n th e NASN . Th e hig hannua l averag e lea dconcentration s foun din th e Lo s Angele s are aar e largel y attributa

bl e t o heav y automotiv e emissions . C.l. 2 Birmingham , Alabam a Durin g 196 4 an d1965 , seasona l level s o f trac e metal s wer e determine dfro msuspende dparticulat e sample s collecte da t

1 0 are asamplin g site s at Bir

mingham , Alabama , a s apar t o f th e Alabam a Respirator y Diseas e an dAi r Pollutio n Stud y initi

ate di n 1962 . Thi s monitorin g stud y produce ddat a representativ e o f

are asourc e industria l pollution . Sample s fro meac ho f

th e 1 0 site s wer e composite d o n aseasona l basi s t o giv e atota l o f 4 0 poole dsam ples . Th e lea ddat aar e summarize di n Tabl e C-2 . Th e maximu mseasona l lea dconcentratio n (3. 5 /ug/m 3 ) occurre dat

Birmingha msit e 4 durin g th e winter . Onl y 2 site s showe daverag e concentration s > 2 figlm 3 fo r

th e year , Birmingha msit e 4 (3. 0 figlm 3 ) an dTarran t

(2. 3 /Ag/m 3 ) . Thes e result s ar e typica l fo r

amedium-size dindustrialize durba n area . C . 1. 3 Kanawh aValley , Wes tVirginia 3 A comprehensiv e ai r

pollutio n stud y wa s con ducte di n th e Kanawh aRive r Valle y in th e vicinit y o f Charleston , Wes t

Virgini a(Figur e C-1) , durin g 196 4 an d1965 . Twenty-four-hou r sample s o f

sus pende dparticulat e matte r wer e collecte da t

1 4 strategicall y locate dsites . Sample s fro mselecte d site s wer e composite do n aseasona l basi s (fal l 1964 , winte r 196 4 an d1965 , an dsumme r 1965 ) an dth e composite s wer e analyze dfo r trace-meta l conten t

b y th e NAS N emissio n spectrographi c procedure . Th e dat afo r lea dar e presente di n Tabl e C-3 . Highes t concentration s o f

suspende dlea dwer e foun ddurin g th e fal l o f

196 4 a t th e St . Albans , Kanawh aCity , an d Charlesto n sites . Lea din dustfal l measurement s (settle dparticu

lates ) fo r th e sam e station s ar e als o presente di n Tabl e C-3 . Th e dustfal l wa s collecte db y exposin g wide-mout hjar s fo r

aperio do f

1 month ; the n com posit e sample s wer e analyzed . Th e highes t averag e concentration s o f

settle dlea doccurre da t th e Smither s sit e (11. 2 mg/m 2 -mo) , an dat th e Sout h Charleston-Eas t

sit e (11. 6 mg/m 2 -mo) . Th e combustio n o f

soli d.fuel s (coa l an dcoke ) i s th e primar y sourc e o f

lea demission s i n th e Kanawh a Valley . Additiona l source s ar e metallurgica l opera tions , asphal t

hot-mi x production , an dothe r in

dustria l processes . I n mos t cases , thes e source s hav e inadequat e ai r

pollutio n contro l equipment . Th e lea dconcentration s foun dar e somewha t lo w whe n C- 1P.8 5

TABL E C-1 . SUMMAR Y O F MONTHL Y AVERAG E LEA D CONCENTRATION S FOUN D I N SEVEN-CIT Y STUDY '

City LO S Angele s

Philadelphi a

Cincinnat i

Lo s Alamo s Housto n

Chicag o

Washington , D.C .

Ne wYor k

a C - commercial ; I - industrial ; R Sit e type 8 C C R R R R I C M C C I R M R R R R C R ' I P F F R C R C C C M R R R M R M C R R M R R C C R R F R R M M R R M R R R R Month s o f dat a 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 7 1 2 1 2 1 2 7 1 2 1 2 1 2 1 2 1 2 1 2 1 1 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 Monthl y concentration ,

Min . 2. 4 2. 6 2. 1 2. 7 2. 1 1. 4 1. 7 2. 5 1. 3 1.2 2. 6 1. 5 0. 9 0. 6 0. 6 1. 1 0. 8 0. 7 1. 3 0. 8 1. 2 0. 5 0. 1 0. 2 0. 1 Q 1 0. 7 0. 7 1. 2 1. 5 1. 0 0. 6 0. 6 1. 0 1. 1 1. 0 1. 3 1. 4 1.2 0. 9 1. 1 1.2 0. 7 1. 2 1. 6 1.4 1. 0 0. 9 1. 8 0. 8 1. 1 1.4 1. 4 1. 3 1. 2 6. 8 0. 9 0. 9 0. 8 ( i g/m 3 Max . 5. 8 6. 8 5. 0 5. 4 4. 4 3. 9 7. 0 7. 6 2. 7 2. 6 5. 1 3. 0 2. 0 1. 7 1. 5 2. 6 1. 7 1. 6 3. 1 2. 6 2. 8 1. 2 0. 5 0. 5 0. 3 0. 3 2. 7 1. 9 3. 2 4. 1 2. 2 1. 4 1. 2 1. 7 1. 7 2. 1 2. 2 2. 3 2. 2 2. 7 2. 1 3. 5 1. 6 2. 2 3. 9 2. 8 1. 7 1. 6 3. 5 1. 8 2. 9 2. 6 2. 1 2. 2 2. 7 1. 9 1. 6 1.4 1.4 Avg . 4. 2 4. 5 3. 6 3. 8 3. 1 2. 5 3. 7 4. 8 1.9 1. 8 3. 8 2. 2 1. 4 1. 1 1. 1 1.7 1.3 1. 0 2. 0 1. 5 2. 2 0. 9 0. 3 0. 3 0. 2 0. 2 1. 2 1. 1 2. 2 2. 4 1.3 0. 9 0. 8 1.3 1.4 1.6 1.8 1.9 1.6 1.3 1.6 2. 0 1. 1 1.7 2. 3 1.8 1.2 1. 1 2. 4 1. 1 1.7 2. 1 1.7 1.7 2. 1 1. 4 1.2 1.2 1. 1

- residential ; M - mixed ; F - farm ; an d P - park . TABL E C-2 . SEASONA L LEA D CONCENTRATION S I N BIRMINGHAM , ALABAMA , AREA , 1964-196 5

(/xg/m' )

Plac e Besseme r Birmingha m Birmingha m Birmingha m Birmingha m Fairfiel d Irondal e Mt . Broo k Tarran t Vestavi a Sit e

1 3 4 5 7 1 1 1 1 1 Seasona l averag e Sprin g 0. 9 0. 7 3. 2 1.2 1.2 0. 6 0. 6 0. 5 1. 1 0. 8 Summe r 0. 7 1. 4 2. 8 1. 6 1.4 0. 5 0. 4 0. 6 1. 8 0. 8 concentration s

Fal l 1. 1 1.7 2. 3 1. 8 1.3 0. 6 0. 9 1.0 3. 0 0. 5 Winte r 0. 6 1.4 3. 5 0. 8 1. 8 0. 3 0. 6 0. 5 3. 4 0. 7 Stud y perio d

averag e concentratio n 0. 8 1. 3 3. 0 1. 4 1. 4 0. 5 0. 6 0. 6 2. 3 0. 7 

### on e consider s th e diversity o f industria l activit

y and th e meteorological an dtopographi c characteristic s prevailing . Th e highes t

value s foundwer

e associate d wit hsamplin g site s adjacent

t o major traffi c arteries , whichdemonstrate s th e contributio n fro mmobil e sources . C . 1. 4 Stud y of Lea d Depositio n in 7 7 Cities 4 

### Settle dparticulate s wer

e collecte di

n 7 7 mid

wester n citie s fro

mSeptember

throug hDecember 1968 . Withi n each city , site s were chosen t o repre sent residential , commercial , andindustria l areas . Th e leadconten t

o f th e settle dparticulate s was determine db

y atomi c absorptio n spectrophotome

try , andth e deposition s wer e expresse da s mg/m2



### - mo . Th e highes t

amount s foundi

n residential , com mercial , andindustria l area s wer e i n Sout hBend , Indian a(8 0 mg/m2 

### -mo i n November) ; Nashville , Tennesse e (34 6 mg/m2 

### -mo i n October) ; andOmaha , Nebrask a(13 7 mg/m2 

### -mo i n November) ; respec tively . Maximumreading s b y mont hoccurre di

n Muncie , Indian a(industrial ) (10 5 mg/m2 

### -mo i n Sep

tember) ; Nashville , Tennesse e (commercial ) (34 6 mg/m2 

### -mo i

n October) ; Omaha , Nebrask a(in

dustrial ) (13 7 mg/m 2 

### -m o in November) ; an d Waterloo , Iow a(industrial ) (9 4 mg/m 2 

### -m o i n , December) . Th e dat aar e summarize di n Tabl e C-4 . C. 2 SOURCE-ORIENTE D AMBIEN T AI R CONCENTRATION S C.2. 1 Souther

n Solano County , California3 

### Th e State o

f Californi aAir

Resource s Board coordinate dajoin t

study , conducte db

y several stat e agencie s between Marc h197 0 an dNovember 1971 , t o determin e th e caus e o f deatho f anumber

o f horse s i n th e Benici aare afro

m196 8 t o 1970 . Figure C- 2 i s ama

p o f thi s are ashowing samplin g site loca

tions . Th e evidenc e strongl y suggeste dthat th e C- 2TABL E C-3 . LEA D DAT A FRO M KANAWH A

VALLE YSTUDY'

Samplin g sites . locatio n an d no . Fall s View (1 ) Smither s (5 ) Montgomer y(6 ) Ceda rGrov e (7) Marmet(11 ) Kanawh a Cit y(13 ) Charlesto n (15 ) Wes t Charlesto n (17 ) Nort h Charleston- W (19 ) Sout h Charleston- E (20 ) Dunba r(22 ) St . Alban s (24 ) Nitr o (25 ) Nitro-Wes t (27 ) Fal l 1964 — 0. 4 — 0. 5 — 2. 1 — — — 2. 7 — 1.3 1.0 — Winte r

1964-196 5 0. 2 0. 3 0. 6 0. 4 0. 5 0. 8 0. 9 0. 7 0. 7 0. 6 0. 4 0. 9 1. 4 0. 1 Sprin g

196 5 — 0. 3 — 0. 2 — 0. 6 — — — 0. 6 — 0. 3 0. 2 — Summe r

196 5 0. 0 — 0. 4 — 0. 5 — — — 1. 0 — 0. 4 0. 3 — Stud yperio d

averag e — 0. 2 — 0. 4 — 1. 0 — — — 1.2 — 0. 7 0. 7 — Lea d i n settle d particulates , mg/m^/mo . stud yperio d averag e 11. 2 6. 7 4. 8 3. 8 2. 8 — 8. 6 11. 6 3. 0 3. 4 —

EASTCHARLESTO N CHARLESTO N CRED E WES TCHARLESTO N NORT H CHARLESTON , EAS T NORT H CHARLESTON . WES T SOUTH CHARLESTON . EAS T SOUTH CHARLESTON , WES T DUNBA R INSTITUT E ST.ALBAN S NITR O WES TO F ST. ALBAN S WES T Q F NITR O Figur e C-1 . Location s o f fixe d samplin g station s i n Kanawh a Rive r Valley. 3 TABL E C-4 . DATA O N LEA D DEPOSITIO N I N 7 7

MIDWESTER N CITIES 4 (mg/m 2 /mo ) Lea d depositio n Lea d depositio n Are a Residentia l Commercia l Industria l Concentration ,

geometri c 5.2 4 9.8 0 12.7 8 mea n Mont h

Septembe r Octobe r Novembe r Decembe r Concentration .

geometri cmea n 9.1 1 8.7 1 9.1 5 8.0 6 horse s die do f

lea dpoisonin g tha t

wa s cause db y in

gestio n o f

lea ddeposite do n pastur e gras s fro ma smelte r plan t a t Selby , California . Th e ambien t ai r concentration s o f

particulat e lea dwer e typica l o f thos e foun di n urba n an dsuburba n areas . I t wa s con clude dtha t

horse s i n thi s are ashoul dno t b e allowe d t o subsis t o n pastur e gras s alone , bu t shoul dreceiv e supplementa l feed . Table s C- 5 an dC- 6 contai n th e dat ao n suspende dan ddeposite dlea dobtaine ddur

in g th e study . Not e tha t th e fallou t

rate s ar e o n a dail y basis .

Figur e C-2 . Ai r samplin g site s fo r Souther n Solan o County , California , study. 5 C.2. 2 Omaha , Nebraska 6 I n Apri l an dMa y o f

1968 , astud y o f

settle dlea d b y th e EP A Divisio n o f Healt hEffect s Researc h showe dcentra l Omaha , Nebraska , t o hav e th e high

es t concentration s o f

deposite dlea do f

2 2 mid

wester n cities . Becaus e automobil e emission s shoul d reflec t th e relativel y lo w populatio n density , th e possibilit y o f

asignifican t

contributio n t o ai r

lea d C- 3P.8 7

TABL E C-5 . LEA D CONCENTRATION S I N AI R DETERMINE D B Y ANALYSI S O F SUSPENDE D PARTICULATE , SOUTHER N SOLAN O COUNTY , CALIFORNIA , MARCH-MA Y 1970 s

Sit e Carquine z Bridg e Ellio t Cov e Babso n hous e Braitodum p Wals h hous e Brait o T V transmitte r sit e Wesne rpastur e Wesne rpastur e Wesne rpastur e Gome z pastur e Wesne rhous e Sa n Francisco " Fremont 0 Sa n Rafael " Distanc e fro m Selby, a k m 1. 9 3. 0 3. 7 5. 6 5 7 7. 7 7. 8 8. 0 8. 3 10. 0 10. 2 22. 0 20. 0 19. 2 Lea d concentration !

Hig h 8.4 5 0.9 3 0.8 2 0.6 9 0.6 2 1.0 7 0.5 6 0.6 6 0.5 1 0.2 8 0.2 2 3.5 0 2.2 4 2.04 Lo w 0.3 5 0.2 7 0.5 8 0.0 7 0.1 4 0.2 5 0.4 0 0.1 1 0.0 3 0.0 3 0.0 2 1.1 5 0.5 9 0.4 1 ,/xg/m 3

Mea n 3.4 9 0.5 2 0.7 0 0.6 4 0.4 0 0.5 9 0.42 0.3 8 0.2 7 0.1 1 0.1 4 2.1 2 1.0 4 1.1 4 a Locatio n o f suspecte d lea d emission s source . Se e text . D 196 9 dat a provide d byBa yAre a Ai rPollutio n Contro l District . TABL E C-6 . TOTA L LEA D AN D LEA D FALLOU T DETERMINE D B Y ANALYSI S O F DUSTFAL L SAMPLES , SOUTHER N SOLAN O COUNTY , CALIFORNIA ,

JUNE-SEPTEMBE R 1970 *

Sit e Distanc e fro m Selby. a k m Sampl e

period , day s Tota l solids . m g Tota l lead , n9 Lea d fallout . mg/m 2 -da y Carquine z Bridg e Brait o dum p Brait o T V trans mitte rsit e Wesne r pastur e Wesne r pastur e Wesne r pastur e Wesne r pastur e Wesne r pastur e Wesne r pastur e Wesne r pastur e Wesne r pastur e Gome z pastur e Drachma n pastur e 1. 9 3 0 49. 2 5. 6 3 0 58. 7 7. 7 6 0 101. 7 8. 0 3 1 37 0 8. 0 3 1 16 2 8. 0 3 1 171. 4 8. 0 3 1 109. 8 8. 0 3 1 351. 7 8. 0 3 1 220. 2 8. 0 3 0 83. 5 8. 3 3 0 163. 6 10. 0 3 2 45. 0 13. 4 3 0 26. 5 143 5 19 5 2.7 8 0.3 8 52 0 18 5 15 5 19 5 25 5 21 0 453 5 43 0 70 5 15 0 7 5 0.5 0 0.3 5 0.2 9 0.3 7 0.4 8 0.3 9 8.5 1 0.8 3 1.3 7 0.2 7 0.1 5 

### fro

mothe r source s (tw o battery plants , on e refinery ) i n th e centra l cit

y are awa s considered . Conse

quently , fro

mMa y t o November

1970 , monitorin g o f ai r leadi n Omah awas conducte da t five sites : on e industria l (I) , on e commercial (C) , on e mixe d(M) , an dtw o residentia l (R) . Al l sample s wer e take n a t 15-f t elevation , an dal l dat awer e reporte da s th e composite daverage s o

f 24-hr sample s collecte d3 time s weekly . Th e monthl y composite averag e o f ai r leadconcentration s a

t th e samplin g site s i s shown i n Figur e C-3 . Air

lea dlevel s i n centra l Omah aa

t site s C an dI wer

e no t onl y comparabl e wit

hthos e of simi

la r site s i n Chicago , Ne

w Yor k City , an dHousto n fro mth e sam

e months , a s reporte db

y EPA , bu t

th e maximummonthl y mea

n a t th e industria l site (i

n July ) exceede dth e maximummonthl y mea n o f al l site s i n thes e othe r

cities .

ATMOSPHERI C LEA D - OMAH A

MONTHL Y COMPOSIT E MAY - NOVEMBE R 197 0

RESIDENTIA L

a Locatio n o f suspecte d lea d emission s source . Se e text . MA Y JU N JU L AU G SE P OC T NO V TIME , month s Figur e C-3 . Omaha , Nebrask a study : mea n monthl y com posit e atmospheri c lea d a t Industrial , commercial , mixed , an d tw o residentia l sites . Mea n i s tha t o f representativ e 24 - hou r sample s collecte d thre e time s weekly . Th e autumna l pea k a t al l bu t th e industria l sit e parallel s th e usua l Omqh a patter n fo r particulates. 6 

### C.2. 3 El Paso , Texas 7 

### ' 8 

### Th e E l Paso , Texas , study wa s initiate di n 197 1 a s aresul t o f th e discover

y o f increase dleaddepositio n i n th e vicinit

y of alocal smelter

whos e emission s C-4

### ros e fro

m25 6 M T i

n 196 9 t o 46 3 M T i

n 1970 . Th e El Pas o City-County HealthDepartmen t the n bega

n specia l ambien t ai r an dsoil samplin g i

n addition t o routin e operatio n o

f thei r nine-statio n particulat e samplin g network . Particulate ' sample s were col

lecte dwit

hhigh-volum e sampler s ove r 24-h r period s andwere the n analyze dfo r leadb y atomi c absorptio n spectroscopy . Th e result s fo r 197 1 fro m th e nine-statio n networ

k ar e given i

n Tabl e C-7 . Dail y samplin g a

t 6 selecte dsite s i

n Smeltertow n was continue dbeginnin g i n February 1972 . Dail y leadconcentration s a

t fou r groun dlevel site s range d fro m0.4 9 t o 7 5 figlm 3 

### an daverage d6. 6 jixg/m 3 

### over 8 6 days . Averag e concentration s o f 3. 6 and6. 5 /ug/m 3 

### were founda

t 2 roofto p sites . TABL E C-7 . LEA D CONCENTRATION S I N SUSPENDE D PARTICULAT E AI R SAMPLE S FRO M E L PASO , TEXAS , 197 V

Locatio n Airpor t Northeas t Canutill o Short yWa y Tillma n Yslet a Coronad o Ker n Executiv e Distanc e fro m k m 12. 8 E 1 6 N E 15. 2 N W 8N W 4. 8 S E 21. 6 S E 4. 8 N 2.4 E 1. 6 N E sample s

8 4 7 3 4 5 75 7 0 7 1 9 4 2 6 6 5 Suspende d atmospheri c

lea d concentratio n Rang e 0.3 8 t o 5.8 2 0.1 2 t o 3.6 8 0.1 0 t o 1.5

0 0.1 8 t o 4.5 1 0.0 2 t o 22.1 6 0.1 8 t o 4.8 1 0.0 8 t o 8.6 2 0.1 2 t o 7.2 8 0.2 6 t o 6.6 7 ./jg/m 3

Averag e 0.9 6 0.7 6 0.4 6 1.0 3 2.6 9 1.3 9 0.8 3 2.7 2 1.1 6 

### C.2. 4 HelenaValley , Montana9 

### Durin g th e summer

andfall o

f 1969 , asource oriente dstudy o

f th e Helen aValley , Montana , are a (Figur e C-4 ) wa s undertake n using dustfal l bucke t an dhigh-volum e samplin g techniques . Durin g thi s period , Helen aresident s were expose dt o a n averag e dail y leadconcentratio n o f 0. 1 figlm 3 

### , wit

hmax imu mconcentration s o

f u p t o 0. 7 /ug/m 3



### . Th e resi

dent s o f th e Eas t Helen aare awer

e expose dt o a

n averag e dail y concentratio n o f 0. 4 t o 4. 0 /ug/m 3 

### , de

pendin g upo n proximity t o th e source , wit h max imu mdail y exposure s of

up t o 1 5 figlm 3



### . Withi n a1

- mil e radiu s o

f th e Eas t Helen asmelter , settle dpar ticulat e leadvalue s range dfro m3 0 t o 10 8 mg/m2



### / mo . Tabl e C- 8 summarize s th e dustfal l an dsus pende dparticulat e dat aacquire ddurin g thi s study , an dFigure C- 4 show s th e depositio n o f lead (dustfall ) i

n th e area .

SCALC . kitamM* ? 

# L

HTTLIAU I ••ARTICULAT

C L f AD . g^>10TO<3 0 1)11 1 >J O T

O < MO Figur e C-4 . Settleabl e particulat e lea d radia l distributio n fro m Helen a Valle y environmenta l pollutio n study. 9 

### C.2. 5 Southeas tMissouri 1 0 

### Studie s wer

e carrie dou t

i n 197 1 i n th e Viburnum ' Tren do r Ne w LeadBelt

i n southeas t

Missouri t o determin e th e magnitud e an ddistributio n o f at mospheri c pollutant s fro

mleadminin g an dsmeltin g operations . Thi s industria l distric t ha s become on e o f th e world' s larges t

lead-producin g area s b

y min

in g more than 392,27 7 M T o f lead , o r 7 5 percen t

o f th e entir e U.S . leadproduction , durin g 1970 . Set

tleabl e particulate s wer

e collecte dmonthl y a

t 1 0 location s i

n wester n Iro n Count

y shown i

n Figur e C-5 . Annual average s fo

r eac hsite ar e include di n th e figure ; monthl y maximumvalue s ar e liste di n Tabl e C-9 . Annua l average s for suspende dlea dcol

lecte di n Glover , Mo . (Site 43 , southeastern Iro n County) , b

y high-volum e sample r

wer e 3. 4 /ng/m3 

### (2 0 samples ) i

n 1970 , 5. 3 /xg/m3 

### (3 2 samples ) i n 1971 , an d5. 6 Mg/m 3 

### (2 8 samples ) i

n 1972 . TABL E C-8 . PARTICULAT E DAT A SUMMAR Y FRO M HELEN A VALLEY , MONT. , ENVIRONMENTA L POLLUTIO N STUDY "

Settleabl e particulat e lead . mg/m 2 /m o Suspende d particulat e lea d i n glas s fibe rfilte rsample , iig/rrfl Statio n 1 2 3 4 6 Location 3

0. 8 mi ; 34 ° 2. 5 mi ; 105 ° 0. 4 mi ; 112 ° 4. 5 mi ; 274 ° 0. 5 mi ; 2 ° Jun . 3 1 54 1 — Jul .

1 9 4 10 6 4 — Aug .

1 0 3 5 3 — Sept .

1 9 9 6 3 7 2 7 Oct .

4 0 1 0 10 8 7 6 0 No . sample s

7 6 8 7 8 5 8 2 3 4 Max .

5. 3 2. 5 16. 0 7. 0 15. 0 Min . < md ° < m d < m d < m d 0. 2 Averag e

0.4 5 0.2 4 1.2 5 0.1 0 3.8 9

a Distanc e an d compas s directio n fro m smelte rstack , b Minimu m detectable . C- 5BUIC KTOWt R # 0« 3

Figur e C-5 . Annua l averag e o f settleabl e particulat e lea d at site s nea r Missour i lea d min e an d smelter , g/m J /Tno. 1 0 

### C.2. 6 Helsinki , Finland "

Investigator s fo r

th e Agricultura l Researc h Center i n Tikkurila , Finland , a

n industria l an dresi

dentia l are anea

r Helsinki , foundhighleadlevel s i n soil . T o clarif

y th e origi n o

f thi s exces s lead , th e In

stitut e o f Occupational Healthconducte dadustfal l leadsurvey i

n th e area . Eight

y collector s were lo

cate dover

a40-km 2 

### are afo

r aperio do

f 1 month , Octobe r 6 t o November

7 , 1970 . Individua l ashe d sample s wer

e analyze db

y emissio n spectrograph y an dth e water-solubl e fraction s were analyze db y atomi c absorptio n spectroscopy . Th e highes t

leaddepositio n value s i n Helsinki wer e observe di

n area s wit

hheavy traffi c an drange d fro m1 0 t o 2 0 mg/m2



### /mo a s compare dt o 0 t o 4 mg/m2 

### /m o i n predominantl y housin g an dresidentia l areas . I n th e Tikkuril aarea , industria l contribution s in

crease ddeposite dlea

dvalue s fortyfol di

n som e areas . Th e deposite dleadvalue s range dfro mback

groun di n outlyin g area s t o a s hig

ha s 20 0 mg/m2



### /m o nea r aleadsmelter , wit

hmos t of th e value s belo w 100mg/m 2

### /mo . C.2. 7 Mez a Rive r Valley , Yugoslavia 1 2 

### I n 1967 , wor

k was initiate di

n th e communit

y o f Zerjav , situate di

n th e Slovenia

n Alp s on th e Mez a TABL E C-9 . PEA K

DEPOSITIO N RATE S O F LEA D MEASURE D I N SOUTHEAS TMISSOURI TM

197 1 Statio n no . Win d

directio n Distance , m Lea d deposi tio n rate , mg/m^/m o Win d frequency , % prevailin g directio n May-Jun e Jul y Augus t Septembe r Octobe r Novembe r 6 7 1 0 7 7 3 E

SS E N E SS E SS E WN W 8 1

9 1 63 3 9 1 9 1 6 1 5.8 8

5.54 4.5 7 7.76 5.1 0 2.0 1 18(S) . 12(WNW ) 14(SSE) , 13(S) . 10(SSW ) 14ISSE) . 1KS) . 10ISSW ) 22IS) . 12ISSE) . 121SSW ) 10(N) . 10(W) . 10ISE) . 1 1 (ESE ) 26(S) . 12ISSW) . 10(WSW).8(SSE ) 

### River , t o investigate contaminatio n b y leado f th e air , water , snow , soil , vegetation , an danimal life , a s well a s th e human population . Th e smelter i n thi s communit y produce s abou t

19,95 4 M T o

f lea dan nually ; unti l 196 9 th e stac k emitte dlea

doxide s withou t contro l b y filter s or

othe r devices . Fiv e sam plin g site s wit

hhigh-volum e sampler s operatin g on a 24-hr basi s wer e establishe di

n th e fou r principa l set tlement s withi n th e Mez aRiver Valle y (Figur e C-6) : (1 ) Zerjav , i

n th e center , th e site of th e smelter , housin g 150 3 inhabitants ; (2 ) Rudarjevo , abou t 2 k mt o th e sout

ho f Zerjav wit

hapopulatio n of

100 ; (3 ) Crna , som

e 5 k mt o th e southwest , populatio n 2198 , where ther e ar e tw o site s (Crna-S E an dCrna

W) ; an d(4 ) Mezica , avillag e abou t 1 0 k mt o th e northwes t

o f th e smelter

wit h251 5 inhabitants . Th e dat ai n Tabl e C-1 0 ar e sufficien t t o depic t

general environmenta l contaminatio n of strikin g propor tions . C.2. 8 Ontario,Canada 1 * 

### Studie s o f lea dconcentration s i

n soils , vegetation , an dth e ambien t

air wer e conducte di

n th e vicinit

y o f asecondar

y smelter an dabattery manufacturin g plan t i n alarg e urban are ai

n southern Ontario . Fo r comparativ e purposes , dat awer e als o collecte di

n a simila r contro l neighborhoo dthat ha dno suchin

dustria l sources . Emission s o f lea dfro mth e smelter wer e estimate dt o b e 1 7 ton s per year ; fro mth e bat

ter y plant , 6 ton s pe

r year . Average s an drange s o f C- 6flIVERS rrfflflp SETTLEMENT

S Figur e C-6 . Schemati cpla n o f lea d min e an d smelte rfro m Mez a Valley , Yugoslavia , study. 1 2 TABL E C-10 . ATMOSPHERI C LEA D CONCENTRATION S (24 - hr ) I N TH E MEZ A VALLEY , YUGOSLAVIA , NOVEMBE R 197 1

T O AUGUS T 1972 1 2 Sit e Mezic a Zerja v Rudarjev o CrnaS E Crna W Minimu m 0. 1 0. 3 0. 5 0. 1 0. 1 P b concentratio n jjg/m ^

Maximu m 236. 0 216. 5 328. 0 258. 5 222. 0 Averag e

24. 2 29. 5 38. 4 33. 7 28. 4 lea dconcentration s ar e summarize din Tabl e C-11 . Bot hsoi l an dfoliag e sample s showe ddefinit e trend s towar dreduce dconcentration s withincreasin g dis

tanc e fro mth e industria l sources . C. 3 CONCENTRATION S O F LEA D I N SOIL S AN D URBA N DUST S A s mentione din Chapte r 5 , surficia l material s i n th e continenta l Unite dState s contai n a n averag e o f abou t 1 5 pp mo f

lead ; 9 4 percen t

o f th e measure ment s showe d3 0 pp mo r less . Highe r

concentration s ar e encountere din th e vicinit y o f lea dor e deposit s and , o f course , i n th e proximit y o f huma n activitie s involvin g lead . Soil s apparentl y receiv e lea di n th e amount s o f

abou t 1 figlcm 2

/yr fro mprecipitatio n an d0. 2 /ig/cm 2 /y r

fro mdustfall 1 4 i n area s remot e fro mintensiv e huma n activity . Thes e smal l addi

tion s t o th e lea dconten t o f th e soi l ar e no t

detectabl e b y ordinar y mean s becaus e the y ad donl y abou t 0. 2 percen t t o th e tota l lea din th e to p 6 in o f th e soil . Lea dlevel s ar e highe r

i n surfac e soil s tha n i n deepe r layers . Swai n an dMitchell 1 5 studie dlea dprofile s i n 8 soi l type s i n Scotlan dan dshowe dtha t th e lea d conten t a t 11 5 c m(4 5 in ) average done-hal f tha t at th e surface . Th e reductio n o f concentratio n with dept hi s als o substantiate db y th e finding s o f others . Goldschmidt 1 6 propose dth e theor y tha t lea di s con centrate din th e humu s o r organi c fractio n o f

soil s i n forest s becaus e i

t i s take n u p slowl y b y tre e root s an d transporte dt o th e leaves , whic hfal l an ddecay . Tyler 1 7 point s ou t

tha t apassiv e io n exchang e favor s a n accumulatio n o f

lea dan dothe r

heav y metal s i n dea dorgani c matter , litter , an dhumus . H e als o state s tha t

mos t plan t materia l subjecte dt o decom

positio n usuall y show s an increas e in th e concentra tio n o f lead , cadmium , nickel , iron , copper , etc. , calculate do n dr y weight . Th e us e o f

leade dgasoline s ha s produce delevate d soi l lea dlevel s adjacen t t o mos t street s an droad

ways . Thi s phenomeno n wa s firs t observe da s earl y a s 193 3 in England, 1 8 an dha s bee n intensivel y TABL E C-11 . COMPARISO N O F LEA D LEVEL S I N TH E SURROUNDING S O F TW O

LEA D INDUSTR Y FACILITIE S AN D A N URBA N CONTRO L AREA " Industr yo r are a Secondar ysmelte r Mea n Rang e Batter yplan t Mea n Rang e Urba n contro l are a Mea n Rang e Soil , pp m (0. 5 c m depth ! 2.61 5 13 3 t o 21.20 0 1.99 6 9 5 t o 17.30 0 48 2 1 8 t o 1.45 0 Tre e foliag e pp m Unwashe d 25 0 3 8 t o 3.53 0 14 9 3 4 t o 45 9 7 3 1 5 t o 25 3 Washe d 18 7 2 7 t o 2.74 0 7 6 1 6 t o 38 7 4 3 10»o12 4 Air , /ig/m ^ (24-hou rsamples ) 3.87 * Max 1 74. 4 2.21 ° Max-31.0 . 1.02 c Max : 4. 0

a Apri l 197 3 t o Ma y1974 . b Novembe r197 3 t o Ma y1974 . c Januar y1974 t o Apri l 1974 . C- 7P.9 1

studie di n recen t

years. 1 9 A n exampl e o f thi s phenomeno n i s take n fro mastud y o f th e Salin e Branc hwatershed , whic hinclude s Champaign , Il

linois . On e face t

o f thi s comprehensiv e study 2 0 con siste do f analyse s fo r

lea di n soi l a t

increasin g dis

tance s fro malow-traffic-volum e stree t (40 0 vehi

cles/day ) an dahigh-traffic-volum e stree t (14,00 0 vehicles/day) . A s show n o n curv e A i n Figur e C-7 , lea dconcentration s stabilize dat abou t 2 0 pp m beyon d1 5 meter s fro mth e low-volum e stree t an d ros e slightl y nea r

th e house . Unfortunately , th e ex terio r constructio n o f

th e hous e i s no t

described . A s curv e B i n Figur e C- 7 shows , lea dconcentration s o f abou t 180 0 pp mi n th e soi l adjacen t t o th e high

volum e stree t

ar e 9 time s highe r

tha n in soi l adjacen t t o th e low-volum e street ; th e concentratio n drop s rapidl y t o aminimu mo f 3 0 pp malittl e mor e tha n 2 0 mfro mth e stree t

an dthe n rise s agai n abruptl y nea r th e hous e t o 9 0 ppm . Thi s hous e i s describe da s bric k an dunguttered . Althoug hsom e leachin g o f lea dfro mpainte dtri mmay b e involved , th e increas e nea r th e hous e i s believe dattributabl e chiefl y t o lea d particle s in traffi c dus t

washe dfro mth e unguttere d roo f b y rai n an ddeposite din th e soi l nex t t o th e house . E 100 0 — a o .

_ • 20 0

DISTANC E FRO M STREET , meter s Figur e C-7 . Soi l transect s b y tw o streets : Curv e A = lowtraffic-volum e (40 0 veh/day) ; Curv e B = high-traffic-volum e (14,00 0 veh/day). 2 0 Soi l lea dlevel s in th e vicinit y o f stationar y source s o f lea demission s ar e ofte n ver y high , and . unlik e th e rapi ddrop-of

f nea r highways , ver y extensive . Thi s i s particularl y tru e fo r

ol dinstallations . Figur e C- 8 show s level s recentl y foun dnea r an ol dsmelte r

in E l Paso , Texas. 2 1 Simila r

data , compile dfro ma3-year

ol dRussia n lea dsmelter, 2 2 ar e show n i n Tabl e C-12 . Th e concentratio n decreas e withbot h dept han ddistanc e i s als o apparen t here . Informa

tio n o n solubl e lea dlevel s in soi l nea r asimila r com ple x i n Grea t

Britia n i s presente din arepor t b y Lit

tl e an dMartin. 2 3 Barltro p reporte dvalue s u p t o 30,00 0 ,u.g/

g in village s i n th e easter n hal f o f Der

byshir e County , England. 2 4 I n thi s instance , th e soi l include dlea dcontaminatio n fro mol dmin e tailing s an dpossibl e natura l mineralization , i.e. , th e con centration s wer e no t

exclusivel y atmospheri c in origin .

DON * ANACOU N

UMTE D STATU !

Figur e C-8 . Surfac e soi l level s (ppm ) o f lea d i n E l Paso , Texas , an d Don a An a County , Ne wMexico , 1972.2 1 TABL E C-12 . LEA D CONTEN TO F SOI L NEA R 3-YEAR-OL D

RUSSIA N SMELTER , E . KAZAKHSTA N (mg/10 0 g air-drie d soil) a Distanc e tro m Surfac e Soi l dept h source , m 50 0 1.000 2.00 0 3.00 0 5.00 0 16.00 0 laye r

23.971 1 9.016 3 1.4207 1.219 2 0.103 1 0.094 3 2 5 c m

4.174 7 1.8368 0.7432 0.599 1 0.064 9 0.077 8 7 5 t o 10 0 c m

0.074 8 — 0.054 5 0.0474 0.023 3 0.029 2 Multiplyin g by1 0 yield s ppm . Tabl e C-13 , derive dfro mstudie s don e in 195 9 an dI960, 2 5 give s lea dlevel s o f soi l adjacen t

t o anothe r Russia n lea dsmelter . Th e plan t i s locate din avalle y surrounde db y mountain s tha t hinde r natura l ventilation . I n addition , plan t emission s ar e inadequatel y controlled . Method s o f sampl e prep aratio n an danalysi s o f th e soi l sample s ar e no t given , however ; no r

i s it state dwhethe r

th e soi l weight s use dwer e fo r

drie do r

undrie dmaterial . Paluc han dKarweta 2 6 reporte dobservation s o n soi l lea dnea r

ane w lead-zin c primar y smelte r i n Po

land . Soi l analyse s wer e mad e in severa l area s prio r t o operatio n o f

th e factor y an dafte r

1 yea r o f opera tion . Sample s wer e extracte dwit hho t concentrate d hydrochlori c aci dan danalyze dfo r lea dconten t

b y th e dithizon e method . Level s foun dar e give n in milligram s o f

lea dpe r kilogra mo f

drie dsoil . Value s C- 8TABL E C-13 . LEA D CONTEN TO F SOI L I N VICINIT Y O F RUSSIA N LEA D PLAN TI N KAZAKHSTAN' S

fro m k m O n ground s 0. 5 1. 0 1. 5 2. 0 3. 0 5. 0 40. 0 Numbe r

o f sample s 1 2 1 0 2 0 6 6 4 4 4 Maximu m 11.170. 0 2.420. 0 1:170. 0 720. 0 1.070. 0 340. 0 97. 0 3. 0 0 t o 1 c m dept h

Minimu m 1.300. 0 470. 0 130. 0 170. 0 250. 0 130. 0 80. 0 2. 5 Lea d conten t o t so i

Averag e 5.546. 0 1.156. 0 613. 0 369. 0 530. 0 235. 0 88. 5 2. 7 , mg/10 0 g a

Maximu m 6.800. 0 650. 0 990. 0 720. 0 610. 0 260. 0 46. 0 Trac e 2 5 c m dept h

Minimu m 510. 0 130. 0 200. 0 70: 0 70. 0 100. 0 40. 0 Trac e Averag e

3.143. 0 458. 0 430. 0 340. 0 260. 0 180. 0 43. 0 Trac e Multiplyin g b y1 0 yield s ppm . give n ar e th e averag e o f thre e samples . Tw o site s ar e o f particula r

interest , awood s o f

youn g pine s 2 k

m fro mth e smelte r

an datre e nurser y a t

3 km . Befor e an dafte r lea dlevel s in th e to p 5 c mo f soi l a t thes e location s wer e 3 9 an d8 9 mg/k g fo r th e former , an d 5 4 an d8 1 mg/k g fo r

th e latter . A t

othe r samplin g site s th e dat awer e quit e variable , bu t thes e wer e agricultura l land s subjec t t o cultivation , t o fertiliza

tion , o r t o both . Th e woode dsite s wer e no t disturbe d in thi s manner . C. 4 REFERENCE S FO RAPPENDI X C 1 . Tepper , L . B . an dL . S . Levin . A surve y o f ai r an dpopula

tio n lea dlevel s i

n selecte damerica n communities . Pre

pare db y Universit y o f

Cincinnati , Cincinnati , Ohio , unde r Contrac t No . PH-22-68-28 . U . S . Environmenta l Protec

tio n Agency . Washington , D.C . Publicatio n No . EPA

RI-73-005 . 1973 . 2 . Hauser , T . R. , J . J . Henderson , an dF . B . Benson . Th e polynuclea r

hydrocarbo n an dmeta l concentratio n o f th e ai r ove r th e Greate r

Birmingha mArea . Huma n Studie s Laboratory , U . S . Environmenta l Protectio n Agency . Researc hTriangl e Park , N.C . Unpublishe dReport . 3 . Kanawh aValle y Ai r Pollutio n Study . U.S . Environmenta l Protectio n Agency . Researc hTriangl e Park . N.C . Publica

tio n No . APTD-70-l . Marc h1970 . 4 . Hunt , W . F. , C . Pinkerton , O . McNulty , an dJ . Creason . A stud y i n trac e elemen t

pollutio n o f

ai r i n 7 7 midwester n cities . In: Trac e Substance s i n Environmenta l Health . IV . D . P . Hemphil l (ed.) . Columbia , Universit y o f Missour i Press . 1971 . p . 56-58 . 5 . Maga . J.A. . F.B . Hodges , C.B . Christenson , an dD.J . Callaghan . A Join t

Stud y o f Lea dContaminatio n Relativ e t o Hors e Death s i n Souther n Solan o County . Lo s Angeles . Stat e o f Californi aAi r

Resource s Board . Septembe r 1972 . 17 8 p . 6 . Mclntire , M . S . an dC . R . Angle . Ai r lead : Relatio n t o lea d i n bloo do f

blac k schoo l childre n deficien t i n glucose-6

- phosphat e dehydrogenase . Science . / 77.520-522 , Augus t 1972 . 7 . Henderson , J . J . an dP . A . Hudson . Unpublishe dtri p repor t re : th e Cit y o f

El Pas o an dStat e o f Texa s (Ai r

Contro l Board ) vs . America n Smeltin g an dRefinin g Compan y (ASARCO) , Caus e No . 70-1701 . Ai r Qualit y Enforcemen t Office , EP A Regio n VI . Dallas , Texas . Ma y 12 , 1972 . 8 . Shearer , S . D . an dJ . J . Henderson . E l PasoSmelte r Briefin g Paper . Environmenta l Monitorin g an dSuppor t Laboratory , U.S . Environmenta l Protectio n Agency . Researc h Triangl e Park , N.C . Ma y 1972 . 9 . Helen aValley , Montana , Are aEnvironmenta l Pollutio n Study . U.S . Environmenta l Protectio n Agency . Researc h Triangl e Park , N.C . Publicatio n AP-91 . Januar y 1972 . 10 . Purushothaman , K . Ai r Qualit y Studie s o f

aDevelopin g Lea dSmelte r

Industry . Rolla . Universit y o f Missour i Press . 1972 . 1 3 p . 11 . Laamanen , A . an dA . Ryhanen . Aeria l distributio n o f dustfal l lea di

n th e neighborhoo do f som e lea demitters . Suome n Kemistilehti . (Helsinki) . 44:367-371 , 1971 . 12 . Fugas , M. , D . Majic , R . Paukovic , B . Wilder , an dZ . Skaric . Biologica l Significanc e o f Som e Metal s a s Ai r

Pollutants . Fina l Report . Par t

I : Lead . U . S . Departmen t o f Health , Education , an dWelfare , Consume r Protectio n an dEnviron

menta l Healt hService . Washington , D.C . Januar y 1974 . Linzon , S . N. , B . L . Chai , P . J . Temple , R . G . Pearson , an d M . L . Smith . Lea dcontaminatio n o f urba n soil s an dvegeta tio n b y emission s fro msecondar y lea dindustries . J . Ai r Pollut . Contro l Assoc . 26(7) : 650-654 , 1976 . Lead : Airborn e Lea di

n Perspective . Washington , D.C,Na

tiona l Academ y o f

Sciences . 1972 . p . 28 . 15 . Swaine , D . J . an dR . L . Mitchell . Trac e elemen t distributio n i n soi l profiles . J . Soi l Sci . //(2):347-368 , 1960 . Goldschmidt , V . M . Th e principle s o f distributio n o f

chemi

ca l element s i n mineral s an drocks . J . Chem . Soc . (London. ) 655-673 . 1937 . 1 3

14 .

1 6

I 7 . Tyler . G . Heav y metal s pollut e nature , ma y reduc e produc

tivity . Ambio . /(2):52-59 , 1972 . 18 . Dunn , J . T . an dH . C . L . Bloxam . Th e occurrenc e o f lead , copper , zinc , an darseni c compound s i n atmospheri c dusts , an dth e source s o f

thes e impurities . J . Soc . Chem . Ind . Lon

do n Trans . Commun . 52.189-192 . 1933 . 19 . Smith , W . H . Lea dcontaminatio n o f th e roadsid e ecosystem . J . Ai r Pollut . Contro l Assoc . 26(8):753-770 , 1976 . 20 . Rolfe , G . L . an dA . Haney . An Ecosyste mAnalysi s o f En

vironmenta l Contaminatio n b y Lead . Institut e fo r Environ

menta l Studies , Universit y o f Illinoi s at

Urbana-Champaign . Researc hRepor t

No . I . Augus t

1975 . p . 53-56 . 21 . Huma n Lea dAbsorptio n - Texas . U.S . Departmen t o f Health , Education , an dWelfare . Atlanta , Georgia . Mor

bidit y an dMortalit y Weekl y Report . 22(49):405-407 , 1973 . C- 9P.9 3

22 . Pakhotina , N.S . Sanitar y hygieni c evaluatio n o f industria l emission s b y azinc-lea dcombine . In: Surve y o f USS R Literatur e o n Ai r

Pollutio n an dRelate dOccupationa l Dis

eases . U . S . Publi c Healt hService . Washington , D.C . J.-93-97 , I960 . 23 . Little , P . an dM . H . Martin . A surve y o f zinc , lea dan dcad

miu mi n soi l an dnatura l vegetatio n aroun dasmeltin g com plex . Environ . Pollut . 5:241-254 , Jul y 1972 . 24 . Barltrop , D . Significanc e o f lead-contaminate dsoil s an d 25 . 2 6 dust s fo r

huma n populations . Arh . Hig . Rad aToksikol . (Yugoslavia. ) 26:81-93 , 1975 . Smokotnina , T . N . Hygieni c evaluatio n o f ai r pollutio n wit h waste s fro malea dplant . Hig . Sanit . (USSR) . 27(6):87-90 , 1962 . Paluch ; J . an dS . Karweta . Th e accumulatio n o f zin c an d lea di n soi l an dplants . In: Lecture s o f 6t h Int' l Congres s o f Forestr y Specialist s fo r

Smok e Damage . Katowice . (Poland. ) 1968 . p . 127-138 .



### C-1 0P.9 4



## APPENDI X D UNIT S AN D METRI C CONVERSIO N FACTOR S

I n eac ho f

th e discipline s dealin g withlea din a secto r o f th e environment , convention s fo r unit s hav e evolve dtha t

ar e convenien t

t o eac hbu t

no t al

way s familiarl y translatabl e fro mon e t o th e other , eve n whe n expresse din metri c units . Ther e ar e als o tw o distinc t

categorie s o f

measurements : concentra tion s an dtransfe r

rates . Withi n eac hcategor y o f measurements , straightforwar dconversio n factor s translat e th e quantitite s fro mon e syste mo f unit s t o another . Connection s betwee n th e tw o categorie s ar e bridge donl y b y mathematica l model s o f varyin g complexit y tha t

accoun t fo r al l significan t

transfe r rates , bot hint o an dou t o f agive n context , a s wel l a s measur e tha t

context' s capacit y t o distribut e an d equilibrat e an y ne t

chang e tha t

will ad dt o o r substrac t fro mit s initia l concentration .

D. l CONCENTRATION S Airborn e lea dconcentration s ar e customaril y re porte din unit s o f

mas s pe r

volume : microgram s o f lea dpe r cubi c mete r

o f ai r (fig/m 3 ). Concentration s o f lea di n soil s an ddust s ar e reporte din unit s o f mas s pe r mass : microgram s o f

lea dpe r gra mo f th e paren t materia l (figlg), o r

a s part s pe r

millio n (ppm) . Whe n pp mrefer s t o mass , th e expressio n i s interchangeabl e wit hfiglg. Concentration s o f

lea din wate r

(dissolve do r

sus pended ) ma y b e reporte di n part s pe r billio n (ppb ) o r microgram s pe r

lite r (/xg/liter) . Fo r

ou r purposes , alite r o f wate r ca n b e equate dwit hlOOOg , an dunit s o f jag/lite r

ca n b e interchange dwit hpp b o r nanogram s pe r

gra m(ng/g) . Concentration s o f

lea di n foo dar e usuall y give n i n part s pe r

millio n (ppm) , microgram s pe r gra m (figlg). o r

milligram s pe r

kilogra m(mg/kg) , al l o f whic har e interchangeable . Concentration s o f

lea di n bloo dma y b e reporte d i n microgram s pe r

decilite r

(figldl) o r

i n microgram s pe r

100 gram s (figll 00 g) . Thes e ar e no t equivalen t

sinc e 1 d l o f

bloo dweigh s betwee n 10 5 an d10 6 g . D. 2 TRANSFE RRATE S I n general , transfe r

rate s describ e th e movemen t o f materia l fro mon e mediu mo r contex t t o anothe r in unit s o f

mas s pe r

tim e o r mas s pe r

quantit y (mas s o r volume ) o f

aparen t material . Som e rate s includ e alinea r o r are adimensio n t o expres s th e transfe r pe r uni t o f interfac e betwee n media . Th e lea din ore s tha t

i s transfere dt o smelter s an d henc e t o manufacture dproduct s i s describe db y pro ductio n figure s an dreporte din ton s (short ) pe r yea r (tons/yr ) o r

tonne s (metric ) pe r

yea r (MT/yr) . Th e attendan t dispersa l o f

som e o f tha t lea dint o th e air , water , an dsoi l i s describe db y emissio n factors : ton s pe r yea r (tons/yr) , kilogram s pe r da y (kg/day) , pound s pe r

to n o f ra w materia l o r

produc t (lb/ton) , pound s pe r

thousan dgallon s (lb/10 3 gal) , gram s pe r kilomete r

(g/km) , etc . Th e mos t

familia r transfe r rat e betwee n medi ai s perhap s th e dustfal l o r depositio n rate , reporte din ton s pe r

squar e mil e pe r

yea r (tons/mi 2 /yr) , milligram s pe r

squar e mete r

pe r mont h(mg/m 2 /mo) , etc . Th e culminatin g concer n i s wit htransfe r rates , in

volvin g th e huma n body , throug hinhalatio n an din

gestio n followe db y retentio n an dabsorptio n int o fluid s an dtissues , and , finally , excretion , al l o f whic har e commonl y expresse di n microgram s pe r day , microgram s pe r

kilogra mo f

bod y weigh t

pe r day , or , even , a s microgram s pe r squar e mete r

o f bod y surface . D- lP.9 5



### D. 3 UNIT S D. 4 CONCENTRATIO N CONVERSIO N FACTOR S 1 m = lOV m = 10 2 c m = 10" 3 k m = 3.28 1 f t = 

### 39.3 7 j n

### 1 PP b (mass ) = 1 ng/

g = Ifiglkg 1 pp m(mass ) = 1 figlg = 1 mg/k g 1 m 2 

### = 10 4 

### cm 2 

### = 10- 6 

### km 2 

### = 10.7 6 ft 2 

### = ] mg/lite r (water ) » 1 ppm» I

figlg 155 0 in 2 

### 1 M 

### g/lite r (water ) *£

* 1 pp b lm 3 

### = 10 6 

### cm 3 

### = 999.9 7 liter s = 35.3 1 ft3 

### = ' ^8 / d l

### (blood ) « 0.9 5 fig/l 00 g (blood ) 6. 1 x 104 

### in 3 

### = 264. 2 ga

l D. 5 TRANSFE RRAT E CONVERSIO N l g = 10 * ug = 10 3 

### mg = 10 3 

### kg = 0.03 5 o z = FACTOR S 0 002 2 1 b 1 mg/m 2 

### /mo = 2.85x10- 3 

### ton s (short)/mr 2 

### /m o 1 tonne/y r - 2.7 4 kg/da

y = 1 tonn e (metric ) = 1000 k g = 10 6 

### g = 1.102 3 ton s (short )/y r 1.102 3 ton s (short ) 1 fig/day = 3.5 3 x 10 8 

### o z (av.)/day

D- 2P.9 6



## APPENDI X E ABSTRAC T O F A REVIE W O F THRE E STUDIE S O N TH E EFFECT S O F LEA D SMELTE R EMISSION S I N E L PASO , TEXA S

Presente d b y Warre n R . IVlui r Counci l o n Environmenta l Qualit y Washington , D.C . A tth e Internationa l Conferenc e o n Heav y Metal s i n th e Environmen t Toronto , Ontario , Canad a Octobe r197 5 Th e committe e reviewe dtw o independen t studie s conducte din 197 3 b y Dr . Landriga n (CDC ) an dDr . McNei l (ILZRO ) t o determin e th e effect s o f communit y lea dexposure s nea r th e ASARC O smelte r i n E l Paso , Texas . Th e CD C stud y use darando msampl e approac ht o grou p participatin g children , an din th e ILZR O stud y matc hpaire dgroup s wer e selecte do n th e basi s o f residence . I n bot hstudie s th e criteri afo r subclassificatio n withregar dt o lea dexposur e wer e bloo dlea dlevels . Neuropsychologica l dysfunctio n wa s evaluate db y severa l test s includin g WISC , WPPSI , an dMcCarth y scales . Statistica l difference s i n tes t result s coul dno t

b e directl y correlate dt o bloo dlea dlevels . Th e opinio n o f

th e committe e wa s tha t n o firmconclusion s coul db e draw n fro mth e studie s a s t o whethe r o r no t ther e ar e subclinica l effect s o f lea do n childre n i n E l Pas o an dtha t th e report s an ddat amad e availabl e hav e no t clearl y demonstrate dan y psychologi c o r neurologi c effect s i n th e childre n unde r study . I t note dth e absenc e o f

majo r chroni c clinica l effects , an dconclude dtha t thes e studie s therefor e d o no t bea r upo n th e con clusion s o f

othe r investigation s unde r

differen t condition s an dthos e i n whic hclinica l effect s hav e bee n con firmed. However , becaus e o f inheren t problem s o f

stud y desig n an dth e limitation s in th e test s used , thi s findin g shoul dno t

lea dt o aconclusio n tha t lo w level s o f

lea dhav e n o effect s o n neuropsychologica l performance . Elle n Silbergeld , Ph.D. , NIH , Eilee n Higham , Ph.D. , an dMr . Russel l Jobaris , John s Hopkin s University , Departmen t

o f Medica l Psychology , serve da s specia l consultants . Th e committe e decide dt o limi t it s focu s t o arevie w o f th e thre e studies , an dt o attemp t t o accoun t

fo r an d interpre t th e difference s betwee n th e studies . Thus , aspect s no t relate dt o difference s wer e no t emphasized . Th e committe e limite dit s consideratio n t o th e followin g materials : (1 ) report s o f th e thre e studie s unde r consideration ; (2 ) othe r material s provide db y th e author s o f th e studies ; (3 ) backgroun dinformatio n an d document s collecte db y Dr . Mui r i n E l Paso . Thi s presentatio n toda y consist s o f excerpt s fro madraf

t com mitte e report . E l HISTOR Y E l Pas o i s situate do n th e Mexica n borde r in th e wester n par t

o f Texas . A lea dsmelte r

owne db y America n Smeltin g an dRefinin g Compan y (ASARCO ) ha s bee n locate do n th e southwester n borde r o f th e city , o n th e Ri o Grand e River , sinc e 1887 . Th e are amos t conspicuousl y involve di n th e studies , Smeltertown , wa s a2 x 6 bloc k are alocate dbetwee n th e plan t an dth e river . Smeltertow n i s n o longe r in existence , havin g bee n destroye di n Decembe r 1972 . Abou t

2 k msout ho f

Smeltertow n i s Ol dFor t Bliss , aconsiderabl y smalle r community , whos e inhabitant s wer e considere din some , bu t no t all , o f th e studies . Th e ASARC O smelte r

produce s lead , zinc , copper , an dcadmium . Particulat e matte r i s remove dfro mair

born e waste s in aserie s o f baghouses ; remainin g emission s contai n approximatel y 4 0 l b o f lea dpe r day . Th e E l Pas o Cit y Count y Healt hDepartmen t bega n an investigatio n o f th e ASARC O smelte r

in earl y 1970 , i n preparatio n fo r

an ai r pollutio n sui t

filedb y th e cit y in Apri l 1970 . A s par t o f thi s investigation , Dr . E- lP.9 7



### BertramCarno w was hire db y th e cit y a s aconsultant . A

t hi s suggestion , th e cit

y bega n t o sampl e th e bloo d lea dlevel s of

E l Pas o childre n t o determin e whether an y hadbeen over-expose dt o lead . Thi s include dalarg e number o f Smeltertow n children . Basedupo n earl y result s i n 1971 , Dr . Carno w visite dE l Paso , an dsa

w a selecte dgrou p o

f childre n wit

hhig hbloo dleadlevels . H e interviewe dth e children , andreviewe dthei r medi

cal records . Th e informatio n containe di n th e medical histories , andDr . Carnow' s interviews , constitut e th e observation s reporte db

y Dr . Carno w i

n th e pape r

presente dt o th e American Pollutio n Contro l Associatio n (APCA). Th e clinical observation s were i n aparagrap ho

f apape r otherwis e devote dt o aconsideratio n o f th e effects o f th e smelter

o n th e environmen t

a s awhole , andth e exten t o f it s emissions . Thi s report contain s n o detail s on th e age , exposures , individua l sign s an dsymptoms , or diagnosti c criteri ause di n th e ten case s re ported . Our

committe e focusedit s attention , therefore , upo n th e tw o full-scal e follow-up epidemiologica l studie s conducte db

y Dr . Landrigan (CDC ) andDr . McNei l (ILZRO) . In 197 3 ASARC O bega

n aseparat e investigatio n of th e populatio n o

f Smeltertown , an daske dDr . Jame s McNei l o f th e Internationa l LeadZin c Researc hOrganizatio n (ILZRO ) fo r hi s assistanc e i

n th e examinatio n an dpossibl e treatmen t

o f childre n wit

helevate dbloo dlevel s greate r than 6 0 mg/10 0 ml . A s aresul t

of publi c concern ove r

widesprea dleadpoisonin g throughou t th e cit y of El Paso , th e mayo r

re queste dai dfro

mth e Federa l Government . A separat e protoco l fo r aCenter fo r Diseas e Contro l (CDC ) study wa s submitte dt o an dapprove db y th e Publi c HealthBoardi n 197 3 wit

hth e understandin g that

th e tw o studie s woul dprocee dindependently , wit hthos e childre n i

n th e ILZR O sponsore dstudy bein g exclude d fro mth e CD C study . In th e summer

o f 1973 , CD C an dILZR O proceede dindependentl y t o collec t dat afo r thei r respectiv e studies . CDC' s examination s wer e don e i n tw o weeks i

n Jun e 1973 , whil e McNeil' s wer e carrie dou t

over th e cours e of th e summe

r wit hth e ai do

f th e E l Pas o publi c schoo l system . Th e CD C grou p supplie dt o th e Committe e dat ai n detail , whichwer

e sufficien t t o allo w th e committe e t o conduc t statistical test s an danalyz e characteristic s o f groups . Fo r

th e ILZR O study , thi s committe e requeste d dat asufficien

t t o carry ou t

simila r in-dept hanalyses . Al l of

th e requeste ddat awere supplied ; however , the y wer e no t i n suc hafor ma s t o allo w recalculatio n o f mos t o f th e statistical finding s o

f th e study o r

t o allo w compariso n wit

hth e CD C findings . E. 2 STUD Y DESIGN Th e environmenta l samplin g tha t wa s performe dwas commo n fo r bot ho f thes e studies . I

n th e selectio n o

f study an dcontro l populations , th e Landrigan CD C study use daclassical approac hof arando msampl e survey t o determin e th e prevalenc e o f abnorma l bloo dleadvalues . Th e 1 3 censu s tract s mos t adjacent t o th e smelter wer e divide dinto thre e areas . Th e samplin g fram e was designe dt o obtai n abou t 100 study subject s fromeac hare afor

variou s ag e groups . O

f 83 3 occupie dresidences , interview s were obtaine dfro m75 8 study subject s i n th e 1-1 9 ag e group . Th e participatin g childre n were divide dint o alead-absorptio n grou p (40-8 0 figllOO ml ) o

f 4 6 andacontro l grou p ( < 4 0 /xg/10 0 ml ) o f 78 . Ther e i s n o detaile ddescriptio n a s t o how th e childre n wer

e chosen . CD C usedthes e same childre n a s th e basi s fo r th e late r study o f neuropsychological dysfunction . Al l bu t 3 childre n chosen fo

r study came fro

mth e 197 2 prevalenc e survey ; 5 childre n wit hknown preexistin g defect s sucha s wit

hahistory o

f symptom s compatibl e wit hacut e leadpoisonin g or acut e leadencephalopath y an d thos e who hadreceive dchelatio n therap y wer e excluded . Whil e i t i s understoo dthat

anumber

o f Smeltertow n childre n wit hbloo dleadlevel s over

4 0 /i.g/10 0 m

l wer e eventuall y involve di

n litigation , mos t

o f themtoo k

part i n th e studies . However , on th e recommenda

tio n of th e lawyer s representin g th e children , at leas t on e grou p o

f 1 8 di dno t

participat e i

n th e ILZR O study . In th e absenc e o

f identificatio n b

y name s o

f th e individual s i

n th e thre e studies , i

t ha s been impossibl e t o evaluat e th e effects o

f non-participation . Th e ILZR O study wa s ver y different ; 13 8 childre n fro mSmeltertow n agree dt o participat e i n astudy . Resi

dence , no t bloo dlead , wa s th e selectio n criterion . Tw o contro l group s were chosen , an dwer e reporte dt o hav e been matche do

n age , sex , ethni c background , an dincome , wit hon e se t chosen fro

mE l Pas o an danothe r

se t for thos e 8 year s o

f ag e o r unde r fro marura l are aabou t

1 2 mile s fro

mth e smelter . Thi s classificatio n hadth e effec t of groupin g togethe r

childre n who , unde r

th e CD C criteria , woul dhav e been i n "lead " an d"control " groups . E- 2Th e criteri ause dfo r subclassificatio n o f

childre n wit hregar dt o lea dexposur e wer e base din bot hstudie s o n th e bloo dlea dlevel . Wherea s th e CD C stud y utilize dbloo dlea dvalue s obtaine da t onl y tw o point s i n time , ILZRO , whic hwa s face dwit hth e proble mtha t man y childre n ha drepeate dbloo dlea dmeasurement s wit hmarke dvariation s ove r aperio do f

1 8 month s (th e level s bein g generall y lowe r afte r exposur e wa s dis

continued) , classifie dchildre n o n th e basi s o f th e averag e o f

th e "tw o highest " recorde dvalues . Thi s criterio n result s in asubstantia l increas e in th e numbe r o f childre n i n th e apparentl y highe r bloo dlea d categor y an dacorrespondin g decreas e i n th e numbe r o f thos e i n th e apparentl y lowe r bloo dlea dleve l category . Althoug hi t

i s understandabl e tha t

thi s typ e o f

selectio n wa s use dt o avoi dunderestimatin g th e proble mo f lea dintoxicatio n i n th e populatio n examined , i t ultimatel y resulte di n muddlin g o f th e separatio n betwee n group s (an dpossibl y obscurin g eventua l differences) . Fo r example , th e selectio n fo r analysi s o f

childre n fro m th e sam e geographica l area , subclassifie daccordin g t o bloo dlea dlevel , in th e ILZR O study , ma y giv e th e im

pressio n tha t

th e effect s o f

lea ditsel f

ar e bein g studie din ahomogeneou s population . However , sinc e ex posur e wa s geographicall y th e same , othe r factor s inheren t

t o eac hindividua l chil dma y b e responsibl e fo r th e differenc e i n bloo dlea dleve l observed . A n additiona l metho do f classificatio n coul dhav e bee n th e us e o f fre e erythrocyti c protoporphyri n measurement s (FEP ) whic hhav e bee n show n t o provid e a n indicatio n o f metaboli c effect s o f

lea dabsorptio n o n metabolism , particularl y usefu l in bloo dlea dleve l range s (40-6 0 figllOO ml ) wher e analytica l an d biologica l fluctuatio n ma y resul t i n uncertai n classification . (Th e ILZR O stud y include dthi s tes t bu t di dno t includ e i t

a s abasi s fo r

dat aanalysis. ) Absenc e o f elevatio n o f

fre e erythrocyti c protoporphyri n ma y indicat e thos e instance s wher e hig hbloo dlea dlevel s wer e spurious . Th e followin g psychometri c test s wer e employe db y th e tw o studies : 1 . Wechsle r

Intelligenc e Scal e fo r

Children , WIS C (CDC , ILZRO ) 2 . McCarth y Scale s o f

Children' s Abilitie s (ILZRO ) 3 . Wechsle r

Preschoo l an dPrimar y Scal e o f Intelligence , WPPS I (CDC ) 4 . Lincoln-Oseretsk y Moto r Developmen t

Scal e (ILZRO ) 5 . Californi aTes t

o f Personalit y Adjustmen t (ILZRO ) 6 . Frostin g Perceptua l Quotien t (ILZRO ) 7 . Bende r

Visual-Moto r

Gestal t Tes t (CDC , ILZRO ) 8 . Peabod y 9 . WRA T 10 . Wepma n 11 . Draw-a-perso n Al l o f th e test s selecte db y bot hstudie s wer e appropriat e fo r th e age s o f

th e childre n t o who mthe y wer e ad

ministered . Sinc e th e commo n groun dfo r thes e studie s i s th e WIS C test , wit hth e WPPS I use db y CD C an dth e McCarth y Scale s b y ILZR O fo r th e younge r

childre n i n thei r

studies , th e Committe e concentrate do n thes e thre e test s an dth e result s obtaine dfo r them . E. 3 RESULT S Th e stud y b y CD C report s result s fo r 2 7 childre n give n th e WPPS I (1 2 wit hbloo dlea dlevel s 40-8 0 figllOO m l an d1 5 wit hbloo dlea dlevel s les s tha n 4 0 figllOO ml ) an dfo r 9 7 childre n teste dwit hth e WIS C (3 4 i n th e "lea dgroup " an d6 3 i n th e "contro l group") . Statistica l analyse s wer e performe do n groupe ddat awithone taile dtests . Significan t

difference s betwee n lea dan dcontro l group s ar e reporte din thi s stud y fo r th e perfor

manc e IQ' s o f

th e WIC S an dWPPSI . I n subtes t scores , significan t

difference s wer e foun di n Codin g o n th e WIS C an dGeometri c Desig n o n th e WPPSI . Whe n dat afro mbot htest s ar e combined , asignifican t differenc e betwee n lea dan dcontro l group s o n performanc e I Q i s found . N o difference s wer e foun dbetwee n group s i n verba l IQ' s o r

full-scal e IW' s o f

th e WIS C o r

WPPSI . Th e ILZR O stud y base do n matc hpairin g solel y b y residence s report s n o significan t difference s in score s o n th e WIS C o r

McCarth y scale s betwee n group s withincrease dlea dabsorptio n an dpair-matche dcontrols . Statistica l analysi s wa s b y mean s o f two-wa y analysi s o f

varianc e b y ag e an dbloo dlea dlevels . Th e tw o studie s bas e muc ho f thei r conclusion s upo n psychometri c an dneurologica l testin g o f childre n fro mE l Pas o an dSmeltertown . Th e reporte dsignifican t difference s an dpsychometri c an dneuromoto r func

tion s i n th e CD C stud y wer e cloude db y potentiall y importan t methodologica l difficulties . Thes e include d E- 3P.9 9



### ag e difference s between cas e an dcontro l groups , limite dstatistical treatmen t o f th e psychometri c dat acol

lected , and , i

n th e ILZR O study , th e us e o f a n averag e o

f th e tw o highes t

bloo dleadlevel s t o categoriz e lead exposure . In addition , bot

hth e studie s share dth e followin g inheren t problems : 1 . Non-rando mexclusio n o f larg e group s o

f childre n 2 . Uncertaintie s a s t o th e selectio n o f contro l group s 3 . Relianc e upo n bloo dleada s th e indicato r o f leadexposur e an dintoxicatio n i n analyse s o

f dat a 4 . Measuremen t

o f alimite daspec t

o f psychological behavio r 5 . Lack o f consideratio n o

f th e potentiall y disruptiv e influence s o n tes t takin g o f th e razin g o

f Smelter

town , closin g o

f it s school , resettlement , litigation , andpubli c controvers y 6 . Inability t o rul e ou t

possibl e preexistin g condition s Th e Committe e stresse dth e las t issue , notin g th e likelihoo dthat an y behaviora l o r

geneti c factor s that

pre dispos e a n individual chil dt o inges t o r absor b more leadthan anothe r chil dequall y expose dma y itsel f b e correlate dt o he resul t

o f psychometri c testing . In othe r word s a n increase dbloo dleadlevel ma y reflect , rathe r than cause , apreexistin g differenc e i n intelligenc e or

behavior , a

n issue inheren t

i n virtuall y al l retrospectiv e studie s o

f th e effects o

f low level bloo dlead . Th e opinio n o

f th e committe e wa s that

no fir mconclusion s coul db e draw n fro mth e studie s a s t o whether o r no t ther e ar e subclinical effects o f leado n childre n i

n E l Pas o andthat

th e report s anddat amad e availabl e hav e no t clearl y demonstrate dan

y psychologi c o r

neurologi c effects i

n th e childre n unde r

study . It note dth e absenc e o f major chroni c clinical effects , andconclude dthat thes e studie s therefor e d o no t bea r upo n th e con clusion s o f othe r investigation s unde r

differen t condition s an dthos e i

n whichclinical effects hav e been con firmed. However , becaus e o f inheren t problem s o

f study desig n andth e limitation s i n th e test s used , thi s find

ing shoul dno t

leadt o aconclusio n that

low level s o

f leadhav e n o effects o

n neuropsychological performance .

£ - 4 * US - GOVERNMEN TPRINTIN G OFFICE ; 1978 —757-140/668 1