TABLE O F CONTENTS

6. OTHER N ON-DIETARYINGESTION FA CTORS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 6

. 1 IN T R O D U C T I O N

............................................... 6-1 6.2 STUDIES RE LATED TO NON-DIETAR Y INGESTION

. . . . . . . . . . . . . . . . 6-2 6

. 2

. 1 D av i s , 1 9 9 5

.............................................. 6-2 6

. 2

. 2 Gr o o te ta l

. , 1 9 9 8

.......................................... 6-5 6

. 2

. 3 R e e d e ta l

. , 1 9 9 9

.......................................... 6-6 6

. 2

. 4 Z art ar i ane ta l

. , 1 9 9 7 an d 1 9 9 8

............................... 6-7 6

. 2

. 5 S t an e k e ta l

. , 1 9 9 8

......................................... 6-8 6

. 2

. 6 F r e e m ane ta l

. , 2 0 0 1

....................................... 6-10 6

. 2

. 7 Jub e r ge ta l

. , 2 0 0 1

........................................ 6-11 6

. 2

. 8 Gr e e n e , 2 0 0 2

............................................ 6-12 6

. 2

. 9 T u l v e e ta l

. , 2 0 0 2

......................................... 6-13 6

. 2

. 1 0 S m i than d N o rr i s , 2 0 0 3

.................................... 6-14 6

. 2

. 1 1 AuY e un ge ta l

. , 2 0 0 4

..................................... 6-15 6

. 2

. 1 2 B l a c k e ta l

. , 2 0 0 5

......................................... 6-16 6

. 3 RE C O M M EN D A T I O N S

......................................... 6-17 6

. 4 RE F E REN C E S F O R C H A P T E R 6

................................. 6-19LIST OF TAB LES Ta ble6-1

. E xtr ap olated To talMo uth ingTi m es M inutes pe r D ay(ti m e aw ak e)

. . . . . . . . . . 6-21 Ta ble6-2

. F req ue nc y o f C ontac t (C ontac ts p er H our)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22 Table 6-3. Preval ence of Non-Food Ingestion/ Mouthing Behavior s by Child’s Age: Per cent of Ch ild ren Who se P are nts Repo rts theBe havio r in thePa st M onth

. . . . . . . . . . . . . . . 6-23 Ta ble6-4 Pe rce nt o f C hil dre n w ith Repo rte d B eh av ior s F rom theTe lep ho ne Surve y C on du cte d i n th e MN C P E S ( n=1 6 8 )

.............................................. 6-26 Ta ble6-5

. M ed ian (Me an ) O bs erv ed Ac tiv ityRate ( Hand Co nta cts Pe r H our) B ase d o n 4 Ho urs o f

O b s e rv at i o nP e r P e r s o n . ............................................. 6-26 Ta ble6-6

. C om paris on of Ob ser ve d A cti vit ies fo r B oy s an d G irl s (M ean)

. . . . . . . . . . . . . . 6-27 Ta ble6-7 . M outhi ngtim es f or P aci fi ers an d O the r O bje cts , b y A ge Categ ory . . . . . . . . . . . 6-27 Ta ble6-8

. Ave rag e Mo uth ingTi m e b y O bje ct C ate go ry and Ag e (min/ hr)

. . . . . . . . . . . . . 6-28 Ta ble6-9 . M outhi ngTi m e S tat ist ics fo r V ari ou s O bje cts (m in/ hr)

. . . . . . . . . . . . . . . . . . . . 6-29 Table 6-10. Esti mated Daily Mouthing Times for Various Objects ( min/day)

. . . . . . . . . . . 6-31 Ta ble6-1 1. Varia bil ityin O bje cts Mo uth ed fo r D if fe rent A ge Gr ou ps . . . . . . . . . . . . . . . . . 6-32 Table 6-12. Mouthi ng Duration by Age Group for Pacifiers , Fingers, Toys, and O th e r O b j e c t s ........................................................ 6-33 Ta ble6-1 3. Ind oo r Mo uth ingFr eq ue nc y (C ontac ts/Ho ur)

. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34 Ta ble6-1 4. Outdo or M outhi ngFr eq ue nc y (C ontac ts/Ho ur)

. . . . . . . . . . . . . . . . . . . . . . . . . 6-35 Ta ble6-1 5. Ind oo r Mo uth ingCo nta ct D uratio n (M inutes /H our)

. . . . . . . . . . . . . . . . . . . . . . 6-36 Ta ble6-1 6. Outdo or M outhi ngCo nta ct D uratio n (M inutes /H our)

. . . . . . . . . . . . . . . . . . . . 6-37 Ta ble6-1 7. Vi de ota pe d M outhi ngan d F oo d-h an dli ngAc tiv ityas M ed ian Ho urly F req ue nc y (Contacts/ Hour) and Median Duration (% of Tape Time) (Mean ± SD)

. . . . . . . . . . 6-38 Table 6-18. Summ ary of Studies on Mouthi ng Behavior

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39 Ta ble6-1 9. Summ ary of Mo uth ingFr eq ue nc y D ata
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40 Ta ble6-2 0. Summ ary of Re co mm en de d V alu es f or T ota l Mo uth ingTi m e ( m i nut e s p e r d ay )

..................................................... 6-42 Table 6-21. Summ ary of Recomm ended Values for Mouthi ng Frequency ( c o nt a c t s p e r h o ur)

.................................................... 6-43 Table 6-22. Confidence in Mouthing Behavior Recomm endations

. . . . . . . . . . . . . . . . . . . . 6-441 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 6. OTHER NON-DIETARY INGESTION FA CTORS

6. 1 IN TROD UC TI ON Young children (i .e., ages 6 months through approximately 4 year s) have the pot ential for exposure to t oxic substanc es through non-di etary inge stion pathways other than soi l ingesti on (e.g., ingest ing pestic ide resi dues that have been transferr ed from treated surfaces to the hands or ob jec ts that ar e m outhe d). Th esech ild ren have anurg e to m outh o bje cts or t he ir f ing ers in
explo rin g th eir envir onm ent, a s a s uc kin g re fl exan d a s a h ab it ( Gr oo t et al. , 1 99 8). Expo sure v ia this rout e may exceed other routes of ingestion (i .e., food, pica, drinking wat er, breastmilk) and dermal exposure, because non- dietary i ngestion may result i n higher inges tion rat es of
co ntam inated m ate ria l (W eav er e t al ., 19 98 ). T his expo sure r oute i s al so dif fi cu lt t o a sse ss be cau se t he re i s li ttl e li ter ature o r re search on m outhi ngbe havio r (Reed et a l., 19 99 ) an d li ttl e inf orm ati on on thesu sceptibil ity of ch ild ren to t ox ic s ub stanc es ( W eav er e t al ., 19 98 ). Mo uth ingbe havio r in clu de s al l ac tiv iti es i n whic h o bje cts , in clu din g f ing ers , are t ou ch ed by the mouth or put into the mouth except for eat ing and drinki ng, and includes l icking, sucki ng, chewing, and biti ng (Groot et al ., 1998). Children’ s contact with surfaces is i ntermittent and nonuniform over different parts of the body and the nature of the mouthing itsel f is intermittent
an d n onun if orm , m akingthi s p athway d if fi cu lt t o m od el ( Zartarian e t al ., 19 97 ). Ch ild ren exhib it l arg e d if fe ren ces in m outhi ngbe havio r (Groo t et al. , 1 99 8). Inf ants are born with a sucki ng reflex for breastfeeding, and within a few months, they begin to use s ucking or mouthing as a means to explore thei r surroundi ngs. Children will use both sucking and lic kin g to explo re the ir e nv iro nm ent. S uc kin g a lso be co m es a m ean s o f c om fo rt whe n a ch ild is tired orupset. In addi tion, teething normally causes subst antial mouthing behavior — sucking or ch ew ing— to all ev iat e d isc om fo rt i n th e gum s. Ea chch ild is dif fe rent, and large dif fe ren ces occur between chi ldren, even within the same fam ily. Mo uth ingbe co m es c rit ica l in expo sure t o p ote nti all y to xic su bs tan ces wh enit i nv olv es the behaviorof a sm all chil d around potenti ally contaminated sources. Childre n play close t o the gro un d and are fr eq ue ntly li ckingthe ir f ing ers or m outhi ngtoy s o r ob jec ts. As a re su lt,
m outhi ngbe co m es a po tentia llysignif icant e xp os ureroute. Ch ild ren m aying est m oretox ic
co ns tit ue nts thr ou ghthi s b eh av ior than f rom die tar y inge sti on or i nh alatio n b eca us e th eym ay

6-11 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 pla ce w et, sti ck y f ing ers on po tentia lly -co ntam ina ted surf ace s, an d m oretox ic s ub stanc es m ay ad he re t o th e f ing ers than if thefi ng ers we re d ry ( Gu run ath anet a l., 19 98 ). Gurunathan et al . (1998) esti mated that young childre n spend as much as 90 percent of their days inside, so expos ure to contaminants that may infiltrate the home through the vapor phase (e.g., volatile or ganic compounds (VOCs) and semi-VOC s (SVOCs)) may be of concern. This may be a significant pathway of exposure to SVOCs because these compounds can be de po sit ed on surf ace s in theho m e o r be co m e ab so rbe d o nto pla sti c to ys or i n s tuf fe d anim als wh ere the y c anser ve as r ese rvo irs fo r to xic co ns tit ue nts (Guru nathan e t al ., 19 98 ). Few studies have i nvestigat ed this pote ntial expos ure route. The s hortage of research and data m aybe du e to thedif fi cu ltyin o bs erv ingve ry y oungch ild ren an d th e la bo r-i nte ns iveef fo rt in g ath eri ngthedata ( Hu ba l et al. , 2 00 0). Th e ap pli cab le r ese arc h e ff ort s u se t wo ge ne ral approaches t o gather dat a: real -time hand recording, i n which traine d persons observe a child and
m anua llyrec ord inf orm ati on on a su rve y s he et o r sc oresh eet ; an d v ide ota pin g, in whic h tr ain ed videographer s tape a chi ld’s act ivitie s and subsequentl y extractthe perti nent data manually or wi th c om puter so ft ware ( Hu ba l et al. , 2 00 0). Som e resear chers expre ss mouthing behavior in te rms of f requency of occurre nce (e.g., contacts pe r hour or cont acts per minute). Other s express mouthing behavioras a rate in units of minutes per hour of mouthing time. B oth approaches have theiruse in exposure assessments. The form er approach i s more appropriate when studying childr en’s behaviorduring vari ous microactiviti es. The latt er, however, is more useful when studying c hildren’ s behavior dur ing
m acr oa cti vit ies

. M acr oa cti vit ies can be de scribe d b y a ch ild ’s g en era l ac tiv iti es s uc h a s sleeping, watc hing televi sion, playing, and eating. Mi croacti vities r efer to the spec ific behavior a child is engaged in such as hand-to-sur face contacts and hand-to-mouth behavior ( Hubal et al., 20 00 ). T im e sp ent in vario us m acr oa cti vit ies in s ev era l m icr oe nv iro nm ents ( e. g. , in do ors at home) are presented i n Chapter 9.

6. 2 ST UD IE S REL AT ED TO NO N- DI ET AR Y I NG ES TI ON 6.2.1 Davis, 1995 In 1992, the Fred Hutchi nson Cancer Researc h Center under Cooperative Agreement with EPA, conducted a study t o estimate childr en’s soil intake rates and coll ect mouthing behavior dat a. Originall y, the study was desi gned with two primary purposes: (1) to desc ribe

6-21 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 and quantify the dis tributi on of soil ingesti on values in a gr oup of children under the age of five wh o e xh ibi t be havio rs that w ou ld b e li ke ly t o re su lt i n th e in ge sti on of large r th anno rm al amounts of soil; and (2) to as sess and quanti fy the degree to which s oil ingest ion varies among children a ccording to s eason of the year ( summ er vs. winter ). The study was conduct ed during the first four months of 1992 and included 92 chil dren from the Tri-Cities area in Washington State. The chil dren were volunt eers among a group select ed through random digit dia ling and their age s ranged between 0 and 48 months. The study was conducted dur ing a 7-day per iod. Because there was no standard methodology to study mouthing behavior, a prete st and a
series of pil ot s tudies we re c on du cte d to ex am inevario us asp ect s o f t he m eth od olo gy . A s a res ult of thepil ot s tudies , it wa s d ete rm ine d th at a lth ou ghparents c ou ld b e ta ught t o c on du ct observati ons using the i nstrument, the resul ting ranki ng of children accor ding to degree of mouthing behavior did not correspond very well to the ranki ngs based on observations of the same children by trai ned staff observers. Ther efore, using parent s’ observat ions to sel ect a group wi th h igh m outhi ngact ivi ty w as n ot d eem ed ap pro pri ate
. F un din g c on str aints m ad e it impractical to c ontinue with the original design of screeni ng a large number of children and
co nd uc tin g f iel d w ork durin g tw o d if fe rent ti m es o f t he ye ar. Th e D av is ( 19 95 ) re search rec ogniz es t hat m outhi ngbe havio r is int ermitt ent. T he ref ore , a p rac tic e ca lle d th e “i nte rva l m eth od ” o f o bs erv ati on wa s u sed

. T his m eth od m eas ure s b oth frequency and durati on of the behavior. Under this method, children were obs erved during 15 second intervals, during whic h the mouthing behavior was rec orded. Based on the types of behaviors obse rved in the t esting of the ins trument, two m outhing behavior s were selec ted for the full study. These included: 1) tongue contact s object; and 2) objectin mouth. In addition fo ur o the r be havio rs w ere inc lud ed in an atte m pt t o b ett er d esc rib e th e ty pe s o f b eh av ior s th at
wo uld lik ely res ult in s oiling est ion : 1) hand tou ch es grou nd ; 2) ch ild is r ep uls ed byob jec t in mouth and tries to get i t out; 3) other person st ops child’s contact with object; and 4) child i s out of

sight o r vi ew . T o f urt he r ch ara cte riz e p ote nti al e xp os ure s to so il a sso ciated wi th t he thr ee types of mouthing behaviors, six obj ect cate gories were i ncluded along with the behavior s: 1) hand , f ing er, or t hum b; 2 ) ot he r bo dyparts , in clu din g to es, fe et, arm s; 3 ) natur al m ate ria ls, including di rt, sand, roc ks, leaves; 4) toys and othe r objects , including books, ut ensils, keys ; 5)
surf ace s, inc ludingwi nd owsil ls, fl oo rs, fu rni tur e, car pe t; and 6) f oo d o r drink

. An a dd iti on al
co de wa s ad de d to indicate whe the r an ob jec t w as s wa llo we d b y th e ch ild

. T he typ e o f a cti vit y
6-31 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 thech ild wa s en ga ge d in durin g th e o bs erv ati on pe rio d w as a lso rec ord ed

. In ad dit ion to
m outhi ngbe havio r data, inf orm ati on ab out ho w l on g th e ch ild sp ent in do ors an d o utd oo rs e ach day, and the gener al types of outdoor s ettings i n which the chil d played was coll ected. Mo uth ingbe havio r data w ere co lle cte d d uri nga 4 -day p eri od

. B oth tra ine d o bs erv ers an d o ne parent ob ser ve d th e ch ild ren to r eco rd m outhi ngbe havio r data. Tr ain ed ob ser ve rs rec ord ed m outhi ngbe havio r data f or 1 ho ur d uri ngact iveplay ti m e, an d th e p are nt r eco rde d mouthing behavior data for the fir st 15 minutes of that hour. Th e b asi c m eas ureof eac h ty pe of m outhi ngact ivi ty d eri ve d f rom theob ser vatio n f orm was the percentof time spent in that act ivity. This measure was defined as the percent age of the total number of interval s observed that indicat e such an acti vity took pla ce. If there was no act ivi ty i n an inter va l, t hat inter va l w as e xc lud ed

. F or t ab ulatin g th e o bje ct c ate go rie s, m ult ipl e instances of the same object in a singl e interva l were counted onl y once in thatinterval

. Mu ltipleins tan ces of dif fe rent ob jec ts i n a sin gleint erv al w ere co unted sep aratel y und er e ach object cat egory. Based on the mouthing behavior dat a collect ed in this s tudy, EPA calculate d that duri ng thepe rio d o f o bs erv ati on (as sum ed to b e 1 ho ur) theav era ge m outhi ngact ivi ty w as 6 .2 m inutes and the avera ge tongue acti vity was 0.70 minutes. It is important to note that this i s based on
on e h our of ob ser vatio n. In o rde r to est im ate theov era ll m outhi ngact ivi ty i n a day, on e w ou ld have to make so me a ss umpt io ns ab out the amountof t ime a c hi ldis invo lv edinac ti ve pl ayti me in a day. Th eseva lue s m ayals o b e und ere sti m ate s b eca us e th eyass um e th at a ll the ch ild ren in thestu dywe re o bs erv ed fo r on e h our on eac h o f t he fo ur d ay s. If thi s w ere tru e, eac h c hil d would have a total of 960 intervals of observations (i .e., 3,600 seconds x int ervals/ 15 seconds x 4 days ). T he data s ho w that th e num be r of int erv als of ob ser vatio n rang ed fr om 80 to 8 40

. It can be co nc lud ed that so m e ch ild ren we re e ith er o bs erv ed fo r le ss t han o ne ho ur o r le ss t han 4 days . In o rde r to co m pare the va lue s es tim ate d b y Groo t et al. (19 98 ) who se w ork als o u sed time as a basis for measuring mouthing activity, it is nec essary to multiply the Davis (1995) ho urly e sti m ate byanest im ate of ho w l on g th e ch ild ren are aw ak e d uri ngtheday. Ac co rdi ngto Davis (1995), small chil dren aged 0 to 48 months are awake appr oximately 8.9 hours per day. Based upon this est imate, the Davis (1995) findings translate into about55 minutes per day of
m outhi ngact ivi ty and 6 minutes pe r day o f t on gu e ac tiv ity

. T he 55 m inutes co m pares favo rab ly to the 37 minutes and 44 minutes estimated by Groot etal. (1998) for 3- t o 6-month and 6- to 12­

6-41 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 m onth o ld c hil dre n, res pe cti ve ly, but is signif icantly a bo ve the16 .4 m inutes an d 9 .3 m inutes est im ate d f or t he 12 - to 18 -m onth and 18 - to 36 -m onth o ld c hil dre n, res pe cti ve ly. Th e d if fe ren ce may be attributable to differences in sl eep time between childr en at either end of the conti nuum of

ag es i nc lud ed in t he stu dy(0 t o 4 8 m onths ). Al tho ugh th e re search inc lud ed thelarge st s am plepo pu lat ion of therev iew ed lit eratur e, 92 sam plepo int s is sti ll a sm allnum be r co ns ide rin g th e w idevaria bil ityass oc iat ed wi th
m outhi ngin c hil dre n. Th e rand om natur e in wh ich thepo pu lat ion wa s se lec ted pro ba bly pro vid es a rep res entat ivepo pu lat ion of theno rthwe st U .S ., but no t th e n ati on al p op ulatio n in ge ne ral

. T he int erv al t im e o f 1 5 s eco nd s w ou ld a lso ap pe ar t o b e sm allan d p ote nti all y e asi ly sk ew ed fo r th os e ch ild ren ob ser ve d le ss t han an h our. I n a dd iti on , m os t ot he r st ud ies us ed ob ser vatio n ti m es o f 1 5 minutes to c ontin uo us ob ser vatio n throu gh out w akingho urs .
6.2.2 Groot et al ., 1998 In this study, Groot et al. ( 1998) examined the mouthing behavior of infants and young ch ild ren be tw een theag es o f 3 an d 3 6 m onths in t he Ne the rland s. Th e st ud y w as p art of a large r effort to determine if PVC toys softened with phthalates could pose health ri sks to chil dren from mouthing. As part of the effort, the investi gators aske d parents t o observe thei r childr en and gather information thatcould be used to e stimate how often children enga ge in mouthing and the durat ion sp ent m outhi ngdurin g a day. Parents w ere ask ed to o bs erv e th eir ch ild ren ten tim es p er day for 15-minute interval s (i.e., 150 minutes tota l per day) for two days and measure m outhing with a stopwatch. I n total, 36 par ents part icipate d in the study and 42 children wer e observed by their par ents. For the s tudy, a disti nction was made between toys meant for mouthing (e.g., pacifiers, t eething ri ngs) and those notmeant for m outhing. The time a child spe nt mouthing a dumm y (e.g., pacifier ) was not incl uded in the ti me recorded.

Al tho ugh th e sam plesiz e w as r elativ ely sm all , th e re su lts pro vid e a f irs t-o rde r es tim ate
on m outhi ngtim es d uri nga d ay . T he res ult s (T ab le 6 -1) sh owwi de variatio n. Th e st an dard de vi at io n i n a ll four a ge cate go ri es ex ce ptth e 3 - t o 6 -mo nth o ldch il dr enex ce ed s the mean t ime est im ate d m outhi ngdurin g a day. Th e largestand ard de viatio ns is n ot u ne xp ect ed giv en theva st be havio raldif fe ren ces fr om ch ild to c hil d and thesm allsam plesiz e o f t he stu dy

. T he ov era ll tr en d o f the data , h owe ve r, may b e a cc ur at e i n that i t s ho ws th atas th e c hi ldre n a ge , the ti me sp ent m outhi ngde cre ase s. Th e 3 - to 6-m onth c hil dre n w ere est im ate d to m outh 3 7 minutes pe r
6-51 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 day and the6- t o 1 2-m onth c hil dre n 4 4 minutes pe r day. Af ter 12 m onths , th e es tim ate d
m outhi ngtim e drop s q uic kly to 1 6 minutes pe r day f or 1 2- t o 1 8-m onth c hil dre n and 9 minutes per day for 18- to 36- month children. The study has sever al limitations that have an i mpact on the usability of the data. The ini tia l dr awba ck co nc ern s th e sm allsiz e o f t he stu dy . T he autho rs o f t he stu dyack no wl ed ge thi s shortcoming and recomm end further study us ing a large r sample population. In a ddition, the stu dyals o in co rpo rat ed m os tly highe r-e du cat ed pe rso ns . T he are a whe re the stu dywa s performed consisted primarily of parent s with higher e ducation. The study had recrui ted persons of lower education and s ocioeconomic levels, butthese pers ons chose not to partici pate in the study after re cruitment. Therefore, the r esults do not reflect data from the full spectrum of the po pu lat ion

. T he stu dyals o re co rde d o nly thetim e sp ent m outhi ngan d n ot t he num be r of tim es that mouthing occurred and did not differentiate the type s of objects mouthed. In additi on, ch ild ren we re o bs erv ed fo r a p eri od of tw o c on sec uti ve days an d m ayno t re fl ect lon g-t erm behavior. Because this study was c onducted in the Netherlands, i t may not be representative of the U.S. population.

6.2.3 Reed et al., 1999 In this study, Reed et al. (1999) used videotapi ng to quantify the frequenc y and type of
co nta cts ch ild ren have durin g th e co urs e o f an h our. T he co nta cts inc lud ed num ero us cat eg ori es: hand to clothi ng, hand to dirt , hand to hand, hand to mouth, hand to object , object to mouth, hand to s m oo th s urf ace(e. g. , c ounte r to ps , ta bletop s), hand to t extur ed surf ace(e. g. , s tuf fe d anim al)

. A total of 30 childr en were observed i n this study. Chil dren were observed in both day car e (20 ch ild ren 3-6 ye ars old) an d re sid entia l (1 0 c hil dre n 2 -5 y ear s o ld) settin gs . P are nts an d d ay car e pro vid ers we re a lso ask ed to c om ple te q ue sti onna ire s d esc rib ingthebe havio r of thech ild ren . In ad dit ion , th e st ud y a lso dif fe rentiated be tw een theus e o f right an d le ft hand s. Ov er the co urs e o f t he res ear ch , th e inve sti gator s f ound that th e b eh av ior of ch ild ren in dayc are an d re sid entia l se tti ng s w as s im ilar ex cep t f or t he co nta ct r ate of hand to s m oo th
surf ace s. Ch ild ren in r esi de nti al s ett ing s h ad highe r co nta ct r ate s w ithsm oo th s urf ace s th an ch ild ren in d aycar e ce nte rs. Th e re su lts of thestu dyare co m pil ed in T ab le 6 -2. Th e h igh est contacts wer e with object(123 contact s/hr), smooth surfaces (84 c ontacts/hr), and other(83
co nta cts /hr). T he tw o lo we st c ontac t rates we re the hand -to -m outh ( 9. 5 c ontac ts/ hr) an d o bje ct6-61 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 to- m outh ( 16 .3 co nta cts /hr). B eca us e th e co nta ct r ate s o f h an d-t o-o bje cts an d s m oo th s urf ace s are high, the se r esults indicate that th e f ing ers wo uld ap pe ar t o p rov idea co nti nu al d os e p er hand-to-mouth contact be cause of constant t ouching of potential ly contaminated surfaces. Pesticide s and other SVOCs are part itioned between the vapor and depos ited phases (e.g., on du st o r ab so rbe d o n a pla sti c to y o r st uf fe d anim al) su chthat a c hil d’s fi ng ers , e sp eci all y if we t fr om m outhi ng , w illco nti nu all y b e ac qu iri ngdo ses of the se t yp es o f c on sti tue nts (Guru nathan e t al., 1998). Th e inve sti gator s al so no ted that ch ild ren act ed eq ua llyon the ir e nv iro nm ent w ithbo th hand s w iththeex cep tio n o f o bje ct- to- m outh b eh av ior

. T he ref ore , th e co m pil ed data are r ep ort ed
as c om bin ed right and lef t hand data. Th e o bje ct- to- m outh b eh av ior sh ow ed a st ron g p ref ere nc e fo r th e ri ght hand ov er the lef t hand fo r ne arl y a ll c hil dre n (Reed et a l., 19 99 ). T he pre fe ren ce ratio for the right hand overthe left hand for thi s category was 6.8 t o 1. Th e ad vanta ge s o f t his stu dyis t hat it inc orp orates a w idevarie ty o f c ontac ts that sm all ch ild ren have , n ot j us t th e h an d-t o-m outh o r ob jec t-t o-m outh. Th is i nf orm ati on all ow s as ses so rs to i de nti fy are as o r surf ace s th at m ayser ve as s ource s f or t ox ic c on sti tue nt t ran sf er. Th is i s esp eci all y im po rtant f or e xp os ureto S VO Cs su chas p est ici de s (e .g ., ch lor pyrif os ) th at h av e an af

fi nit y f or a bs orp tio n o nto du st p art icl es, pla sti c to ys , and int o th e p oly ure thane fo am (P UF ) th at is used in many stuffed animals (Gurunathan et al ., 1998). Another str ength of this study i s the agreement it shows with ear lier work by Zartarian e t al. (1998) for the hand to mouth contacts. So m e o f t he sh ort co m ing s ar e th e sm allsam plesiz e o f t he stu dyan d th e la ck of co mm ent as to therep res entat ive ne ss o f t he sam plepo pu lat ion to t he U. S. po pu lat ion . T he autho rs acknowledged the weaknes s in regar d to the sample size and r ecomm ended further work with a large r po pu lat ion

. T he stu dym ak es n o m entio n o f t he rep res entat ive ne ss o f t he sam ple population oraddresses the need for a repre sentati ve population for any a dditional study.

6.2.4 Z artarian et al ., 1997 and 1998 Zartarian e t al . (1 99 7, 19 98 ) co nd uc ted a p ilo t st ud y o f f our ch ild ren of farm wo rke rs t o inv est igate the ap pli cab ili ty o f u sin g v ide ota pin g f or g ath eri nginf orm ati on rel ate d to ch ild ren ’s interac tion with the ir envir onment. The evaluation of the videot aping include d observati on of thech ild ren ’s c ontac t f req ue nc y and durat ion wi th obje cts in t he ir e nv iro nm ent, d uratio n s pe nt i n different locati ons, activi ty levels , and frequency distr ibutions.

6-71 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Four Mexican- Am erican farm worker childr en— two girls and two boys between the ages of 2.5 and 4.2 years— were vi deotaped for 33 hours usi ng hand-held cameras over the
co urs e o f a sin gleday in 19 93

. T he vid eo tap inggathe red inf orm ati on on de tai led m icr o-a cti vit y patterns of children to be us ed to evaluat e software for videotape d activit ies and tr anslati on traini ng methods The data were also re ported by type of objec t/surface and by l eft or right hand. The investigators pres ented the dat a for their obse rvations on aper child and per hand ba sis

. N on e o f t he ch ild ren ha d ave rag e co nta ct f req ue nc ies fo r ei the r hand , in div idu all y, low er than 3 co nta cts /hr fo r hand to m outh c ontac t, and theinv est igator s es tim ate d th e av era ge as 9
co nta cts /hr wi th an ave rag e rang e o f 1 to 2 9 c ontac ts/ hr. As als o repo rte d b y Reed et a l. ( 19 99 ), the most frequently contact ed objects wer e toys and hard ( i.e., smooth) surfaces. The avera ge co nta ct t im e w ithob jec ts i s o nly 2 to 3 s eco nd s; the ref ore , a cco rdi ngto t he autho rs, questionnai res and diar ies would be insufficientin gatheri ng that leve l of activity. This study has se veral weakness es. The sample population is very small, only four ch ild ren ; ho we ve r, t he wo rk w as r ep ort ed as a pil ot s tud y c om ple tel y a ck no wl ed gin g th at f urt he r work was necessary. The e ffort was intended to eval uate the methodology of collect ing ob ser vatio ns , n ot t he co nta ct d ata its elf

. T he data are n ot p res ented in a fo rm at that can b e u sed to support other research or supply r ecomm ended estimates for contac t frequency. This study may not reflect long-term behavior. In addition, the sample population is notrepresent ative of theU. S. po pu lat ion in g en era l.

6.2.5 Stanek et al ., 1998 Stanek et al . (1998) prese nted a methodology that char acteri zes the pre valence of mouthing behavior among healthy childre n . Data regardi ng the frequency of 28 mouthing behaviors were collect ed via face-to- face intervi ews over a peri od of 3 m onths from parents or guardians of 533 chil dren ages 1 to 6 ye ars old attending well- visits i n W estern Ma ssachusett s. Three cli nic s p art icipated in t his stu dydurin g th e m onths of Au gu st, Septe m be r, and Oc tob er, 19 92 : K ais er P erm an ente’ s cl ini c in Am he rst , a pri vate c lin ic a sso ciated wi th t he Co ole y Dickinson Hospital in Northampton, and the Bay State Me dical Centerclinic i n Springfield. Parti cip ants w ere qu est ion ed ab out th e f req ue nc y o f 2 8 m outhi ngbe havio rs o f t he ch ild ren ov er the past month in additi on to exposure t ime (e.g., time outdoors, play in sand ordirt) and

6-81 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ch ild ren ’s c harac terist ics (e. g. , te eth ing ). Resp on se c ate go rie s o f t he cli nic qu est ionna ire
co rre sp on de d to da ily , at le ast we ekly, at l eas t m onthly, an d n ev er. Th e autho rs e xp res sed them outhi ngrat e f or e ach ch ild as t he sum of rat es f or r esp on ses to four questions on mouthing speci fic outdoor object s. Regression models with vari ables in a step-w ise m anne r id entif ied fa cto rs r elated to h igh outdo or m outhi ngrat es. Th e autho rs f irs t considered variables that indi cated opportunity for exposure, then subjects ’ charact eristi cs (e.g., tee thi ng ) an d e nv iro nm entalfa cto rs, an d f ina lly , c on curre nt r ep ort ed be havio rs. Ta ble6-3 pre sents the pre va len ce o f n on -f oo d in ge sti on/m outhi ngbe havio rs b y c hil d’s ag e as thepe rce nt o f c hil dre n who se p are nts rep ort ed thebe havio r in thepa st m onth. Th e ta ble includes a c olumn of data for the 3 to < 6 year age cat egory; thi s column was calculated by EPA
as a we ighted m ean va lueof theindivi du al d ata fo r 3- , 4 -, and 5-y ear -ol ds in o rde r to co nf orm to the standar dized age cat egories use d in this Handbook. Outdoor s oil mouthing behavior pre va len ce w as f ound to b e h igh er t han in do or d us t m outhi ngpre va len ce, but bo th b eh av ior s h ad thehighe st p rev ale nc e am on g 1 -ye ar- old ch ild ren an d d rop pe d q uic kly am on g c hil dre n 2 ye ars old and older. The i nvestigat ors conducted pr incipal c omponent analyses on responses to four qu est ion s re lat ingto i ng est ion /m outhi ngof outdo or o bje cts (T ab le 6 -3) in an atte m pt t o characte rize var iabili ty. Responses were conve rted to mouthing rate s per week, using val ues of 0, 0.25, 1, and 7 for responses of never, monthly, weekly, and dai ly ingesti on. Outdoor ingestion/mouthing rates for were 4.73 per week and 0.44 pe r week for childre n 1 year of age
an d 2 -6 y ear s o f age , re sp ect ive ly. Th e f req uen cywi th whic h c hil dre n p lay ed in s an d/dirt wa s est im ate d a s a m eas ureof po tentia l expo sure; 71 % of thech ild ren we re r ep ort ed to h av e p lay ed in sand or dirt at lea st weekly, and 45% wer e reporte d to have played i n the sand or di rt dail y. Th e autho rs f ound that ch ild ren wh o p lay ed in t he san d o r di rt h ad highe r outdo or o bje ct ing est ion /m outhi ngrat es. Thus , c hil dre n w ithhighe r di rec t expo sure t o s an d o r di rt w ere m ore lik ely to i ng est or m outh o utd oo r ob jec ts. Th e inve sti gator s f ound similar re su lts wh en co m parin g th e ti m e sp ent outdo ors to r ep ort ed outdo or i ng est ion an d m outhi ngrat es; thedata indicate t hat 65 % of on e-y ear old ch ild ren an d 4 2 p erc ent of ch ild ren 2-6 ye ars old sp en d le ss than 3 ho urs pe r da y o utd oo rs. A s tre ng th o f t his stu dyis that it fo cu ses on thepre va len ce of

sp eci fi c b eh av ior s to qu antif y s oilm outhi ngor i ng est ion am on g h eal thy ch ild ren . T he res ult s of

thi s st ud y might have im po rtant h eal th i m pli cat ion s as it s ho we d th at 1 -ye ar- old ch ild ren wi th high general levels of mouthing behavior have the potentia l for high risk s oil ingest ion.

6-91 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 A limitation associ ated with thi s study is that the dat a are based on r ecall behavior from thesumm er p rev iou s to theint erv iew

. E xtr ap olatio n to oth er s eas on s m aybe dif fi cu lt. In ad dit ion , d ata we re c oll ect ed fo r ch ild ren in W est ern Mas sac hu setts and data w ere on ly ava ila ble fo r th e h eal thy ch ild ren wh o w ere pre sent f or w ell -vi sit s.
6.2.6 Freeman et al., 2001 As part o f t he Minne so ta C hil dre n’s Pe sti cid e E xp os ureSt ud y (MNC PE S) , m acr oa cti vit y and microactivity data were coll ected via que stionnair e from the families of a group of 168 children, and a subset of 19 of these chil dren were videot aped for four consecutive hours during the months of August and September 1997. The children were between the ages of 3 and 12 ye ars old an d w ere liv ingin b oth urb anan d ru ralare as o f M inn eso ta. Fo r th e ti m e/a cti vit y qu est ionna ire s, theparents p rov ide d th e re sp on ses fo r ch ild ren ag es 3 an d 4 , and co lla bo rat ed with or assi sted olderchildren with their r esponses. The videot apes were anal yzed using the
m eth od s repo rte d b y Reed (19 99 ), and fo r co m paris on , f our ch ild ren ’s v ide ota pe s w ere als o analyzed usi ng the VideoTraq tr anscript ion system described by Zartarian e t al. (1995)

. Vi de ota pe s w ere trans cribe d o nc e f or t he lef t hand an d o nc e f or t he right h an d, an d th e f req ue nc y of six behaviors ( hand-to-mouth, hand-to-obj ect, object -to-mouth, hand-to-smooth surface, handto-textured surface, and hand- to-clothing) was recor ded. The amount of tim e each chil d spent ind oo rs, outdo ors , in co nta ct w ithso il o r gr ass , and wh eth er the ch ild wa s b are fo ot w as a lso
rec ord ed

. S tat ist ica l an aly ses we re p erf orm ed us ingSP SS an d S ys tat
. Fo r th e su rve y re sp on ses , o nly eat ingfo od dro pp ed on thefl oo r w as s ign if icantly greater fo r on e ag e grou p (3 -4 y ear old s), wh en co m pared to t wo oth er a ge gro up s (T ab le 6 -4)

. Whe n thesurve y re sp on ses we re f urt he r br ok endo wn byag e, the3-y ear -ol ds ha d s ign if icantly m ore po sit iveres po ns es f or all r ep ort ed be havio r co m pared to t he oth er a ge gro up s. Hi ghres po ns e rates ( >70%) to addi tional ques tions dir ected toward the 3- and 4-year -old chil dren, regar ding the use of blankets and toys indic ated thatthese quest ions should al so have been asked of the older chil dren. Am on g th e f our ag e categ ori es s tudied fo r th e 1 9 v ide ota pe d c hil dre n, ob jec t-t o-m outh activit ies were si gnificantly gr eater for the 3-year-ol ds than any otherage group, with a mean of 6 contacts pe r hour (P = 0.002) ( Table 6-5). Contac t with clothing was slight ly more frequent

6-101 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 and contact with smooth surfaces less frequent among the two oldestgroups of children, but neither of thes e differences was stat istica lly signi ficant. Gender differences were obse rved for some of the activitie s, with boys spending signif icantly m oretim e o utd oo rs than g irl s (T ab le 6 -6)

. H an d-t o-m outh and ob jec t-t o-m outh activit ies were le ss frequent outdoor s than indoors for both boys and girl s. No significant differences were observed in the frequency of event s recorded us ing the Reed manual counting sy st em andth e V id eo Tr aqco mput er -b as edvi de o trans cr ip ti onsy st em. The advantage of this s tudy is thatit contai ns both survey and vi deotaped information on mouthing behavior, and that various ages wer e studied. The l imitations of the study ar e that the sample size is small and was from a limited area (urban ar ea of St. Paul/Minneapolis) not rep res entat iveof thenatio na l po pu lat ion in g en era l.

6.2.7 Juberg et al., 2001 Ju be rg e t al . (2 00 1) u sed a d iar y-b ase d a pp roa chto r eco rd m outhi ngbe havio r in ch ild ren up to three ye ars of age. An initi al pilotstudy involved 30 c hildren, i ncluding 15 between the ages of 0 and 18 months and 15 between the ages of 19 and 36 months. A second phase of the stu dyad de d 9 2 c hil dre n to theyo un ge r gr ou p and 95 to t he old er grou p, fo r a t ota l po ole d d ata set of 10 7 and 11 0 p ers on s, res pe cti ve ly. Fo r th e p ilo t an d s eco nd stu dy , d iar y f orm s w ere distri buted to approxi mately 450 fam ilies; the distr ibution was spl it equall y between a
co mm erc ialch ild play re search center an d a nurs ery sch oo l/d ay car e ce nte r. P are nts we re a sk ed to observe their chil d’s behavioron a single day of thei r choosing duri ng a three- week period, and record the insert ion of objects int o the mouth by noting the “ti me in” and “time out.” Mo uth ed ite m s w ere cla ssi fi ed as p aci fi ers , te eth ers , p las tic toy s, or o the r ob jec ts. In t he data
an aly sis , p aci fi ers we re e xam ine d a s a s ep arate c ate go ry and data f or a ll o the r it em s w ere po ole d into a “non-pa cifier” cat egory. The results of the combined pilot and Phase II data are s hown in Table 6-7. For both a ge groups, mouthing time for pacifiers greatl y exceeded mouthing time for non-pacifiers, with the difference more acute for the olderage group than for the younger age group. Hist ograms of the observed datashow a peak in the l ow end of the distribut ion (0 to 100 minutes per day) and a rap id d ecl ineat l on ge r du rat ion s.

6-111 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 A third phase of the study focused on children be tween the ages of 3 and 18 months and inc lud ed on ly n on -pa cif ier s. Su bje cts we re o bs erv ed fo r 5 n on -co ns ecutiv e d ay s o ve r a 2 -m onth period. A total of 168 participant s returne d surveys for at l east one day, pr oviding a tot al of 793 pe rso n-d ay s o f d ata . T he data y iel de d a m ean m outhi ngdurat ion of 36 m inutes pe r day; t he m ean was the same when calculated on the basis of 793 person- days of data as on the ba sis of 168 da ily av erage m outhi ngtim es. Th e ad vanta ge s o f t his stu dyare that it inv olv ed a largenum be r of parti cip ants c om pared to other studies of mouthing behavior. It al so exhibite d consistenc y of results from the pilot stu dyto t he sec on d and third p ha ses . T he po tentia l so urc es o f e rro r in clu de thelimite d geographic r ange of the study (west ern New York state) and the subjec tive natur e of the observati on and diary-ba sed approach. Anotherlimitation of this study is that i t focused on ob jec t m outhi ngbe havio r an d d id n ot i nc lud e h an d-t o-mouth b eh av ior

.
6.2.8 Greene, 2002 Th e U .S . C on sum er P rod uc t S af ety Co mm iss ion (C PS C) inv est igated thepo tentia l he alth risks to c hildren underthree year s of age from teether s, rattl es, and toys made from polyvinyl ch loride(P VC ) co nta ini ngvario us dia lky l phtha lat e (D AP ) pl ast ici zer s. Th eyco nd uc ted an observati onal study to quantify the cumulative ti me per day that young childr en spend mouthing ob jec ts, inc ludingtoy s an d o the r ch ild ren ’s p rod uc ts. Th e st ud y w as c on du cte d f rom De cem be r 19 99 thr ou ghFe bru ary 20 01 in t wo ge ograp hic al area s: H ou sto n, TXan d C hic ag o, IL

. S ub jec ts were recrui ted using te lephone random digit dial ing technique s. During the firstphase of the study, the parent or l egal guardi an observed the child and
rec ord ed allm outhi ngbe havio rs f or f our 15 -m inute s eg m ents o ve r tw o d ay s. If thech ild wa s un de r 36 m onths of ag e, the y w ere rec rui ted to p art icipate i n p ha se I I. D uri ngph aseII, a tr ain ed observer r ecorded the c hild’s behavior for a tota l of four hours on at leas t two different days. Th e o bs erv ati on s w ere do ne at dif fe rent ti m es o f t he day at ho m e o r a t he ch ild car e f aci lity attended by the child. A tota l of 491 children participat ed in phase I. The t otal number of partici pants in phase II was 169. The age of the chi ldren were between 3 months and 3 years of ag e. Of the16 9 c hil dre n in ph aseII, 10 9 p art icipated in p ha se I

. D ata fr om ph aseI w ere analyzed and r eported inde pendently from phase II and were notprovided by Greene ( 2002).

6-121 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Ta ble6-8 pro vid es t he av era ge m outhi ngtim e b y o bje ct c ate go ry and ag e in m inutes pe r hour. Mouthing t ime statistic s by object categories and age are pr esented in Tabl e 6-9. The
av era ge m outhi ngtim e f or a ll o bje cts ran ge d f rom 5. 3 to 10 .5 m inutes pe r ho ur, wi th t he highe st mouthing time corresponding to chil dren <1 year of age and the lowest to the 2-3 years of age. Am on g th e o bje cts m outhe d, pa cif ier s repre sent ab out on e th ird of thetot al m outhi ngtim e, wi th 3.4 minutes per hour for the youngestchildren, 2.6 minutes perhour for the chil dren between 1
an d 2 ye ars an d 1 .8 m inutes pe r ho ur f or c hil dre n o ve r 2 y ear s o ld. Th e n ext large st s ing le i tem category was anatomy, representing chi ldren s ucking fingers and thumbs. In this category, children unde r 1 year of age spent2.4 minutes per hour and it decli ned with age, with the 1.2 minutes per hours for the 2-3 ye ars old. Da ilym outhi ngtim es w ere est im ate d u sin g a bo ots tra p p roc ed ureus inga n orm all y dis tributed ran do m varia blefo r th e expo sure t im e b ase d o n th e ch ild ’s a ge . T he bo ots tra p pro ced ureis a statis tic al t echniq ue in whic h a set of co lle cte d d ata is r an do m ly s ub -sam ple d hundreds or thous ands of times in order to empirical ly derive c onfidence limits on the mean of them ain sam pleset . T heem pirica l di stributio n o f m outhi ngtim e w as u sed to c alc ulate s tat ist ics
an d c on fi de nc e inter va ls and wa s se lec ted ind ep en de ntly o f e xp os uretim e. Th e b oo tst rap th sampling was done 5000 times to generate mean, median, and 95 percenti le daily mouthing tim e f or e ach ag e grou p and ob jec t categ ory . T he res ult s o f t he bo ots tra p p roc ed ureare presented i n Table 6-10. The est imated m ean daily mouthing time for non-pacifiers r anged from 37 min/day to 70 m in/day with the lowest number correspondi ng to the 2-3 years old and the largestnumber corresponding to the 3 months -12 m onths old.

6.2.9 Tulve et al., 2002 In t his stu dy , p rev iou sly un pu bli sh ed data f rom theFr ed Hutch ins on Canc er Rese arc h Center, Seatt le, Washington were analyzed. Dat a were colle cted by tra ined observer s who described and quantified the mouthing behaviorof 90 children in their home environment. The ch ild ren ran ge d in ag e f rom 10 -60 m onths

. T he ob ser ve rs r eco rde d m outh and ton gu e co nta cts with hands, otherbody parts, natural objec ts, surfaces, and t oys every 15 seconds for a minim um of

15 m inutes
. C hil dre n’s act ivi tie s w ere co de d a s q uie t or act iveplay, an d lo cat ion s w ere co de d as i nd oo r or outdo or e nv iro nm ents. Th e f ina l data s et that w as ana lyz ed fo r th is s tud y in clu de d only those chi ldren who were coded as engaging in quie t play in an i ndoor environment (72

6-131 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 children, r anging in age from 11-60 months). A total of 186 observations were included i n the study, with the number of observati ons per chil d ranging from 1-6. Data analyses t o evaluate the influence of age and gender wer e conducted usi ng a linearSAS m odel (Versi on 8.02; SAS Ins tit ute , C ary , N C)

. Results of the dataanalyses i ndicated that there was no associat ion between mouthing fr eq ue nc y and ge nd er, but a c lear as so ciatio n b etw een m outhi ngfr eq ue nc y and ag e w as observed. Using a tree analys is, childr en # 24 months had the highest frequency of mouthing behavior (81 e vents/hour) and childre n >24 months had the lowest (42 event s/hour) ( Table 6-11). Bo th grou ps of ch ild ren we re o bs erv ed to m outh t oy s an d h an ds m orefr eq ue ntly th anbo dyparts oth er than h an ds an d s urf ace s. The advantage of this s tudy is thatmouthing data is provided for di fferent age groups and fo r a v ari ety of ob jec ts ( m outh- bo dy , -h an d, -su rf

ace , and –to y). Th is s tud y is limite d in that it focuses on childre n involved in qui et play in an indoor envir onment.

6.2.10 Smith and Norris, 2003 Sm ith and Norri s (2003) conduct ed a diary- based observat ional study of mouthing be havio r am on g 2 36 ch ild ren be tw een theag es o f 1 m onth and 5 y ear s. Ch ild ren we re o bs erv ed at home by parents, who recorded the time that mouthing began, the type of mouthing (licki ng, sucking, chewing, et c.), the type of object being mouthed, and the ti me that m outhing cease d. Chi ldre n we re ob se rv edfora t ot al of 5 ho ur s ov era two- we ekpe ri od ; the ob se rv at io n t ime consisted of twenty 15- minute periods evenly di stribut ed through the week and throughout the ch ild ’s w akingho urs . Resu lts of thestu dyare sh own in Ta ble6-1 2. Whil e n o o ve ral l patte rn co ul d b e fo un d i n the di ffe re ntag e g ro up s t es te d, a Kru sk al -Wa ll is te stonth e d at a fo r a ll it ems mouthed indicated thatthere was a si gnificant difference between the age groups. Acr oss all age gro up s an d ty pe s o f i tem s, lic kin g and su ckingacc ounte d f or 6 4% o f a ll m outhi ngbe havio r. Pa cif ier s an d f ing ers exhib ite d le ss v ari ety on m outhi ngbe havio r (p rin cip all y s uc kin g), wh ile other it ems had a higher frequency of licking, bi ting, or othe r mouthing. Th e p rin cip al a dv antag e o f t his stu dyis i ts i nc lus ion of thetyp e o f m outhi ngbe havio r in thesurve y. Ho we ve r, i t su ff ers fr om thesam e li m itatio ns as m any o the r surve y-b ase d s tudies , including obse rver bias , a relat ively low sample size ( especial ly when broken down by age), and a l imi te d g eo gr ap hi c s co pe . T he study wa s c on du ct edinth e Uni te d Ki ng do m.
6-141 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 6.2.11 AuYeung et a l. , 2004 AuYeung et a l. videotaped 38 chi ldren (20 female and 18 male; ages 1-6 year s) for two hours during i ndoor and outdoor pl ay. Children were r ecruite d for the study by cal ling tel ephone
num be rs r an do m ly e xtr act ed fr om thetel ep ho ne dir ect ory fo r an ap pro xim ate ly 4 00 sq uare mile portion of the San Franc isco peninsul a. Families who lived in a r esidence with a lawn and wh os e annu al i nc om e w as > $3 5, 00 0 w ere ask ed to p art icipate. Vi de ota pin g to ok pla ce b etw een Au gu st 1 99 8 and May 19 99

. M os t of thevid eo tap ingtoo k p lac e d uri ngoutdo or p lay , h ow ev er, data were inc luded for several children ( one child <2 years old and 8 chi ldren >2 year s old) who ha d m orethan 1 5 minutes of ind oo r pl aydurin g th eir vid eo tap ingses sio ns . T he vid eo tap es w ere translated into ASCII computer files usi ng VirtualTimingDevice TM software, which allowed the duration of very short mouthing events to be captured. For analysis , the mouthing contacts were divided int o indoor and outdoorlocations , and 16 ob jec t/s urf acecat eg ori es. Mo uth ingfr eq ue nc y, co nta ct d uratio n, an d h ourlydurat ion we re a ll
an alyzed byag e an d g en de r separat ely , and in c om bin ati on . M outhingco nta cts we re d ef ine d a s contact with the lips, i nside of the mouth, and/or the tongue ; dietary contacts wer e ignored. No np aram etric t est s, su chas t he W ilc ox on rank s um tes t w ereus ed fo r th e d ata an aly ses . Mo uth ingfr eq ue nc ies fo r in do or l oc ati on s ar e sh own in Ta ble6-1 3. Fo r th e o ne ch ild ob ser ve d th at w as # 24 m onths , th e to talm outhi ngfr eq ue nc y w as 8 4. 8 c ontac ts/ ho ur; fo r ch ild ren >2 4 m onths , th e m ed ian ind oo r m outhi ngfr eq ue nc y w as 1 9. 5 c ontac ts/ ho ur. Outdo or m ed ian mouthing frequencies (Table 6- 14) were very si milar for children # 24 months (13.9 contacts/hour) and >24 months (14.6 contact s/hour). Fo r th e ch ild ren in all a ge gro up s, them ed ian durat ion of eac h m outhi ngco nta ct w as 1 -2
sec on ds , c on fi rm ingtheob ser vatio ns of oth er r ese arc he rs that ch ild ren ’s m outhi ngco nta cts are of

ve ry s ho rt d uratio n. Fo r th e o ne ch ild ob ser ve d th at w as # 24 months, the total indoor mouthing duration was 11.1 minutes/hour; for chi ldren >24 months, the median indoor mouthing durat ion wa s 0 .9 m inutes /ho ur ( Ta ble6-1 5). Fo r outdo or e nv iro nm ents, m ed ian co nta ct durat ion s f or t he se a ge gro up s d ecr eas ed to 0 .8 an d 0 .6 m inutes /ho ur, res pe cti ve ly ( Ta ble6-1 6). Bo th a ge an d g en de r w ere fo un d to be ass oc iat ed wi th dif fe ren ces in m outhi ngbe havio r. Children # 24 m onths ha d s ign if icantly lo ng er h an d-t o-m outh c ontac t du rat ion s th anold er children ( p = 0.04), but no signi ficant age-r elated di fferences were found in mouthing frequencies or hour ly mouthing durations. Girl s had significant ly higher frequenc ies of

6-151 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 m outhi ngco nta cts wi th t he hand s an d n on -di etary o bje cts than b oy s ( p = 0.01 and p = 0.008, respecti vely). Girl s’ hand-to- mouth contact durations were also si gnificantly shorter than for bo ys ( p = 0 .0 4).

This study is us eful in that i t provides di stribut ions of outdoor mouthing frequencies and durat ion s w itha v ari ety of ob jec ts and surf ace s. Al tho ugh in do or m outhi ngdata are a lso included in this study, the results are based on a s mall num ber of children ( n =9 ) an d a limite d amount of indoor play.

6.2.12 Black et al ., 2005 In a recentstudy, the mouthing and food-handling behavior of 52 childre n (26 boys and 26 girls) from 29 homes in the m id-Rio Grande Vall ey was videotaped a s part of a year- long pestici de exposure study (Black et al ., 2005). The childr en were grouped int o four age categori es: infants ( 7-12 months), 1-year-ol ds (13-24 months), 2-year- olds (25-36 months), and preschooler s (37-53 months). Detaile d baseline and activity questionnai res were administer ed,
an d e ach ch ild wa s v ide ota pe d f or f our ho urs . T he ch ild ren we re f oll ow ed bythevid eo gra ph ers through the house and yard, exceptfor times when they were napping or usi ng the bathroom. Re co rds we re k ep t of any s ign if icant i nte rru pti on s d uri ngvid eo tap ing

. V irt ua l T im ingDe vic e so ft ware, a re fi ne m ent of thevid eo tap e so ft ware d esc rib ed byZartarian e t al . (1 99 7) w as u sed to
an alyze t he vid eo tap es. St ati sti calPa ck ag e f or t he So cia l S cie nc es s of tw are wa s u sed to ana lyz e m icr oa cti vit y d ata an d q ue sti onna ire res ult s. Most of the chil dren (49 of 52) spent the majority of their ti me indoors. Of the 39 ch ild ren wh o s pe nt t im e b oth ind oo rs and outdoo rs, allthr ee b eh av ior s (h an d-t o-m outh, ob jec tto-mouth and food handling) were more frequent and longerwhile the chi ld was indoors. Handto-mouth activity was r ecorded duri ng the videotaping for all but one child, a 30-month-old gir l. For the four age groups, the mean hourly hand-to-mouth frequency ranged from 11.9 (2­ year-olds ) to 22.1 (pre schoolers) , the mean hourly object- to-mouth frequency ranged from 7.8 (2-year- olds) to 24.4 ( infants), and the mean hourly hand-to-food frequency ranged from 10.8 (infants) t o 17.2 (1-year- olds). Significant lineartrends were obs erved for hourly obj ect-tomouth f requency, which decr eased as age i ncreased ( adjusted R2 = 0.179; P = 0.003) , and handto-mouth frequency, which increas ed with incre asing food contact freque ncy for children ove r 12 months (adjusted R2 = 0.291; P = 0.002). Resul ts of this study are shown in Table 6- 17.

6-161 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 The advantage of this s tudy is thatit incl udes both survey and videotaped i nform ation on
m outhi ngbe havio r. T he limitatio ns of thi s st ud y are that th e sam plepo pu lat ion wa s f airly s m all
an d w as f rom a li m ite d area (m id- Ri o Gran de Va lle y) n ot r ep res entativeof thenatio na l population i n general. I n addition, the duration data in thi s study is pr esented as “ % of tape tim e” and canno t beco nv ert ed to a “m inutes /day”fo rm at f or c om paris on wi th o the r st ud ies

.
6.3 RECOMMENDA TIONS Due to the paucity of the availabl e resear ch data, mouthing frequency data shoul d be
us ed wi th c autio n. Ta ble6-1 8 s umm ari zes thestu die s o n m outhi ngbe havio r th at w ere de scribe d in this chapter. Table 6- 19 summ arizes the mean m outhing time and frequencies for hand- tomouth, object-to-mouth, and totals from these studi es. Table 6-20 and 6- 21 summ arize the
rec omm en de d m ean va lue s f or m outhi ngtim e an d f req ue nc y, res pe cti ve ly, fo r th e re co mm en de d ag e categ ori es. Th e d ata fo r ea chof thestand ardize d a ge cat eg ori es i n T ab le 6 -20 an d 6 -21 are calculat ed as a weighted mean of values from studies in this chapter that are r elevant t o each age cat eg ory . In so m e ca ses theag e categ ori es u sed in t he stu die s d id n ot c orr esp on d e xa ctl y to EP A’ s re co mm en de d a ge gro up s. In t ho se c ase s, theclo ses t ag e grou p w as u sed as i nd icated in the Tables 6- 20 and 6-21. As mentioned earlie r, the studi es in this chapter use different units of reporti ng mouthing behavior. If the asses sor is int erested i n estimating exposures during
m acr oa cti vit ies , th enthetot al am ount o f t im e en ga ge d in m outhi ngbe havio r (T ab le 6 -20 ) m ay be the unit of int erest. I f the assessor i s intere sted in est imating exposures to var ious microactiviti es, then the number of contacts with hands or object s per unit of ti me (Table 6-21)
m aybe theun it o f i nte res t. N o d ata we re ava ila blefo r in fants fr om bir th t o < 1 m onth o ld. Th ere we re a lso no rec omm en datio ns pre sented fo r 1 t o < 3 m onths in T ab le 6 -21 an d 6 -22 or f or 3 to <6 years in Tabl e 6-20. Smith and Norris (2003) i ncluded chil dren from 1 - 5 years of age. However, the study is biased high bec ause it i ncluded chil dren who were sucking their thumb or fi ng er. Ac co rdi ngto S m ithan d N orris ( 20 03 ), t his ef fe ct i s m oresignif icant i n th e o lde r ch ild ren in the study. Total mean m outhing time ranged from 7 m in/day to 65 min/day, with the lowest value correspondi ng to 2 to 6 years old and the highe st value corresponding to 6 t o <12 months old. To talm ean m outhi ngfr eq ue nc y rang ed fr om 5 c ontac ts/ hr t o 5 4 c ontac ts/ hr, wi th t he low est
va lueco rre sp on din g to the6 to <1 1 y ear s o ld and thehighe st v alu e co rre sp on din g to the1 to <2

6-171 2 3 4 5 6 7 8 years old. Me an hand-to-mouth contactranged from 4 contacts/hr t o 20 contacts/hr, with the low est va lueco rre sp on din g to the6 to <1 1 y ear s o ld and thehighe st v alu e co rre sp on din g to the6 to <12 months old. Ta ble6-2 2 p res ents the co nf ide nc e ratin gs fo r th e re co mm en de d v alu es. Th e o ve ral l confidence rati ng was low because sample sizes wer e small for som e of the age groups. Children’s be havior is di fficult to measure and somewhat subjective bec ause it depe nds on the
expe rie nc e o f t he ob ser ve r.

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6-20Tabl e 6- 1. Ext r apol at ed Tot al M out hi ng Ti m es M i nut es perD ay ( t i m e a w ake)

A ge ( m ont hs) N o. C hi l dr en M ean St andar d D ev. M i ni m um M axi m um 3 - 6 5 36. 9 19. 1 14. 5 67 6 - 1 2 1 4 4 4 4 4 .7 2 .4 1 7 1 .5 1 2 - 1 8 1 2 1 6 .4 1 8 .2 0 5 3 .2 1 8 - 3 6 1 1 9 .3 9 .8 0 3 0 .9
N o te : T h e o bje c t m o st m o u th e d in a ll a g e g ro u p s in th e fin g e rs e x c e p t fo r th e 6 - 1 2 m o n th g ro u p w h ic h m o stly m ou t hed on t oy s. Sour ce: G r oot etal

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6-21T ab l e 6 -2. Freq u en cy of C o n t ac t (C o n t ac t s p er H o u r)

V a ria b le M e a n M e d ia n M in im u m M a x im u m 9 0 th P e rc e n til e C lo th in g 6 6 .6 6 5 2 2 .8 1 2 9 .2 1 0 3 .3 D irt 1 1 .4 0 .3 0 1 4 6 .3 5 6 .4 H a n d 2 1 .1 1 4 .2 6 .3 1 1 6 .4 4 3 .5 H a n d to m o u th 9 .5 8 .5 0 .4 2 5 .7 2 0 .1 O bje c t 1 2 2 .9 1 1 8 .7 5 6 .2 3 1 2 1 7 5 .8 O bje c t t o m o u th 1 6 .3 3 .6 0 8 6 .2 7 7 .1 O th e r 8 2 .9 6 4 .3 8 .3 2 4 3 .6 1 9 9 .6 S m o o th su rfa c e 8 3 .7 8 0 .2 1 3 .6 1 9 0 .4 1 3 6 .9 T e x tu re d su rfa c e 2 2 .1 1 6 .3 0 .2 6 8 .7 5 2 .2
Sour ce: R eed et al

. ( 1999)

6-22T able 6- 3. Preval enc e of N on - Fo od I ng est i on / M ou t hi ng B eha vi ors by C hi l d’s A ge: Pe r cen t of C hi l dren W ho se P a re n ts R e p o rts th e B e h a v io r in th e P a st M o n th

N on- Food Pr eval ence C hi l d’s A ge (years) I nges t i on/ m out hi ng of B ehavi or 1 2 3 4 5 6 3 to < 6 a A ll N =171 N =70 N =93 N =82 N =90 N =22 N = 265 N =528 O ut door “ soi l ” mout hi ng/ I nges t i on Sand, s t ones % > M ont hl y 54 2 6 19 9 7 9 12 27 % > W eekl y 36 10 6 2 4 5 4 16 % D ai l y 17 0 2 1 1 5 1 6 G r ass, l eav es, fl o w ers % > M ont hl y 48 16 24 13 9 5 16 26 % > W eekl y 34 7 14 4 6 0 8 16 % D ai l y 16 0 2 1 1 0 1 6 T w i gs, st i cks, w oodchi ps % > M ont hl y 42 23 13 13 11 5 12 23 % > W eekl y 29 7 9 5 7 0 7 14 % D ai l y 12 0 0 1 0 0 0 4 Soi l , di r t % > M ont hl y 38 21 5 7 3 9 5 18 % > W eekl y 24 7 3 2 1 9 2 10 % D ai l y 11 0 1 0 1 0 1 4 D ust , l i nt , dus t bal l s % > M ont hl y 14 4 2 0 0 5 1 6 % > W e e k ly 7 1 1 0 0 0 0 3 % D a ily 2 0 0 0 0 0 0 1 Pl as t er , cha l k % > M ont hl y 8 10 3 2 3 5 3 5 % > W e e k ly 5 3 0 1 0 0 0 2 % D a ily 2 0 0 1 0 0 0 1 P a in tc h ip s, s p linte rs % > M o n th ly 6 0 0 4 1 0 2 3 % > W e e k ly 2 0 0 1 0 0 0 1 % D a ily 0 0 0 0 0 0 0 0 G en er a l m o u thin g of o b jec ts O t her t oys % > M ont hl y 88 53 64 44 42 23 50 62 % > W eekl y 82 44 42 26 28 9 32 49 % D ai l y 63 27 20 9 7 5 12 30 Paper , ca r dboar d, t i ss ues % > M ont hl y 71 37 32 23 18 14 24 41 % > W eekl y 54 23 20 12 7 9 13 28 % D ai l y 28 9 8 5 2 5 5 13 Teet hi ng t oys % > M ont hl y 65 29 15 4 3 9 8 29 % > W eekl y 55 16 9 1 1 9 4 22 % D ai l y 44 6 6 0 0 9 2 17

6-23N on- Food I nges t i on/ m out hi ng Pr eval ence of B ehavi or C hi l d’s A ge (years) 1 2 3 4 5 6 3 to < 6 a A ll N =171 N =70 N =93 N =82 N =90 N =22 N = 265 N =528 C r ayo ns, pen ci l s, era se rs % > M ont hl y 56 54 46 50 41 36 46 50 % > W eekl y 41 37 25 27 26 27 26 32 % D ai l y 19 17 4 6 4 18 5 12 B l anket s, cl ot h % > M ont hl y 51 21 26 22 22 14 23 32 % > W eekl y 42 17 17 18 14 14 16 25 % D ai l y 29 11 9 13 7 5 10 16 Shoes, Foot w ar e % > M ont hl y 50 23 8 7 2 5 6 22 % > W eekl y 42 10 3 2 1 5 2 16 % D ai l y 20 1 0 0 0 0 0 7 C l ot hi ng % > M ont hl y 49 34 37 43 26 27 35 39 % > W eekl y 39 24 23 28 16 14 22 27 % D ai l y 25 7 11 9 6 14 9 14 O t her i t em s % > M ont hl y 41 30 30 23 21 27 25 31 % > W eekl y 35 26 24 15 10 14 16 23 % D ai l y 22 11 15 7 6 5 9 14 C r i b, cha i r s, furn i t u re % > M ont hl y 37 11 8 10 4 5 7 17 % > W eekl y 26 9 3 5 2 0 3 11 % D ai l y 13 3 1 1 0 0 1 5 S u ck i n g of fi n g er s, etc Suck f i nger s/ t hum b % > M ont hl y 67 41 43 57 39 41 46 52 % > W eekl y 60 27 31 43 31 18 35 41 % D ai l y 44 21 22 26 24 14 24 30 Suck f eetor t oes % > M ont hl y 37 14 12 11 3 0 9 18 % > W eekl y 23 4 3 2 1 0 2 9 % D a ily 8 1 0 1 0 0 0 3 U se pac i f i er % > M ont hl y 24 9 6 2 2 5 3 11 % > W eekl y 22 9 5 2 2 0 3 10 % D ai l y 20 6 5 1 1 0 2 9 Suck hai r % > M ont hl y 1 3 8 9 10 5 9 5 % > W e e k ly 1 3 2 2 4 5 3 2 % D a ily 1 1 1 0 2 0 1 1

6-24N on- Food Pr eval ence C hi l d’s A ge (years) I nges t i on/ m out hi ng of B ehavi or 1 2 3 4 5 6 3 to < 6 a A ll N =171 N =70 N =93 N =82 N =90 N =22 N = 265 N =528 “D i sgus t i ng” obj ect m out hi ng/ i ngest i on S o a p , d e te rg e n t, sha m poo % > M ont hl y 48 34 24 17 9 9 17 29 % > W eekl y 37 27 14 11 6 9 10 21 % D ai l y 15 14 3 2 0 0 2 8 Pl as t i c, pl as t i c w r ap % > M ont hl y 32 19 8 7 9 0 8 17 % > W eekl y 22 11 3 4 4 0 4 10 % D a ily 7 4 1 0 1 0 1 3 C i garet t e bu t t s, t obacc o % > M ont hl y 16 6 5 4 3 5 4 8 % > W eekl y 10 4 4 1 2 5 2 5 % D a ily 4 0 1 1 1 0 1 2 M a tc h e s % > M o n th ly 6 4 1 4 1 0 2 4 % > W e e k ly 2 3 1 1 1 0 1 2 % D a ily 1 0 0 0 0 0 0 0 In se c t % > M o n th ly 5 1 2 4 2 0 3 3 % > W e e k ly 2 0 1 4 2 0 2 2 % D a ily 0 0 1 2 2 0 2 1 O t her i ngest i on and behavi ors Toot hpas t e % > M ont hl y 63 97 92 94 93 86 93 84 % > W eekl y 60 94 91 93 92 86 92 82 % D ai l y 52 87 86 93 89 82 89 77 C hew gum % > M ont hl y 18 56 76 76 91 1 0 0 81 58 % > W eekl y 10 40 60 60 69 68 63 43 % D ai l y 3 17 18 13 21 36 17 14 B i t e na i l s % > M ont hl y 8 26 31 29 33 59 31 24 % > W eekl y 5 23 24 20 26 45 23 18 % D ai l y 2 7 12 9 10 14 10 7 Suck hai r % > M ont hl y 62 76 85 96 88 73 89 78 % > W eekl y 57 64 77 88 81 68 82 71 % D ai l y 42 39 43 55 52 45 50 45

aW ei ght ed mean of 3- , 4- , and 5- year - ol ds’ dat a c al cul at ed by EPA t o conf or m t o s t andar di zed age cat egor i es u se d in th is H a n d b o o k

. S o u rce : Stan ek et al. (19 9 8 ).

6-25Tabl e 6- 4. Pe r c e nt of C hi l dr e n w i t h R e por t e d B e ha vi or s Fr om t he Tel e phone Sur ve y C onduc t e d i n t he M N C P E S (n = 1 6 8 ).

R e por t e d B e ha vi or 3- 4 Y e a r s ( n=27) Per c e nt R e por t e d by A ge G r oup 5- 9 Y e a r s ( n=93) 10- 12 Y e a r s ( n=48) H a nd- t o- m out h 56 39 35* N on- f e e d i t e m s i n m out h 52 31 37 Eat s f ood dr oppe d on f l oor 48 10 4** Eat s m os t f ood w i t hout u te n sils 37 29 19*

P u ts p a in t ch ip s in m o u th 0 0 0

x 2 t est , *P < 0

. 1 0 be t w een y o u n g est an d oldest grou p s; ** si g n i fi can t dif fer en ce across t h ree grou p s. Sour c e : Fr e e m a n e t a l

. , 2001 Tabl e 6- 5. M e di a n ( M e a n) O bs e r ve d A c t i vi t y R a t e ( H a nd C ont a c t s PerH our ) B a s e d on 4 Hours of O bs e r va t i on PerPer s on.

O b se rv e d A c tiv ity A ge 3- 4 ( n=3) A g e C at eg o ry ( Y ears) 5- 6 ( n=7) 7- 8 ( n=4) 10- 12 ( n=5) O bj e c t
- t o- m out h*** 3 ( 6) 0 ( 1) 0 ( 1) 0 ( 1) H a nd- t o- m out h 3. 5 ( 4) 2. 5 ( 8) 3 ( 5) 2 ( 4) Touch c l ot hi ng** 26 ( 34) 22 ( 26) 50 ( 54) 35 ( 53) Touch t e xt ur e d s ur f a c e * 40 ( 52) 20 ( 32) 22 ( 58) 16 ( 24) Touch s m oot h s ur f a c e 134 ( 151) 111 ( 120) 120 ( 155) 94 ( 96) Touch obj e c t 130 ( 153) 117 ( 132) 111 ( 164) 127 ( 179) K r us ka l W a l l i s t e s t c om pa r i s on a c r os s f our a ge gr oups : *P=0. 1108; **P=0. 0796; ***P=0. 002. Sour c e : Fr e e m a n e t a l

. , 2001

6-26T ab le 6 -6

. C o m p ariso n o f O b se rv ed A ctiv it ies fo r B o y s an d G irl s (M ea n ).
O bs e r ve d A c t i vi t y B oys ( n=8) G i r l s ( n=11) H o u rs sin c e las t h a n d w a sh 5 .9 3 .5 T im e sp e n t o u td o o rs (m in u te s) * 1 0 4 .4 5 4 .0 T im e sp e n t in d o o rs (m in u te s) * 1 3 4 .3 1 8 6 .0 H a n d -to -m o u th in d o o rs /h o u r* 4 .7 8 .1 H a n d -to -m o u th o u td o o rs /h o u r 1 .7 2 .3 O bje c t-to -m o u th in d o o rs /h o u r 1 .0 2 .6 O bje c t-to -m o u th o u td o o rs /h o u r 0 .1 1 .0 * P < 0 .0 5 b y M a n n -W h itn e y tes t. Sour c e : Fr e e m a n e t a l

. , 2001

T ab l e 6 -7. M o u t h i n g t i m es for P ac i fi ers a n d O t h er O bj ec t s, by A g e C ateg o ry

O bj ectType A ge 0 t o 18 mont hs A ge 19 t o 36 mont hs A ll R e sp o n d e n ts

( m i nut es / day) D o e rs O n ly a ( m i nut es / day) A ll R e sp o n d e n ts ( m i nut es / day) D o e rs O n ly a ( m i nut es / day) Paci f i er 108 ( n = 107) 221 ( n=52) 126 ( n=110) 462 ( n=52) N on- Paci f i er T ee t h er Pl as t i c Toy O th e r O bje c ts 33 ( n=107) b 6 ( n=107) 17 ( n=107) 9 ( n=107) not ca l cul at ed 20 ( n=34) 28 ( n=66) 22 ( n=46) 5 ( n=110) b 0 ( n=110) 2 ( n=110) 2 ( n=110) not ca l cul at ed 30 ( n=1) 11 ( n=21) 15 ( n=18)

a D o e r s o n ly ana l ys i s r ef er s t o m ea ns ca l cul at ed f or t he s ubs et of t he s ampl e popul at i on t hat par t i ci pat ed i n t he a ct i vi t y; ze r oes ar e e l i m i nat ed f r om t he c al cul at i on of t he mea n. b Tot al f or non- pac i f i er s m ay not equa l s um of i ndi vi dual i t ems due t o r oundi ng. Sour ce : J uber g et al

. , 2001

6-27T ab l e 6 -8 A v era g e M o u t h i n g T i m e b y O bj ec t C ateg o ry a n d A g e (m i n / h r)
O bj ectC at egor y A l l A ges 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs A ll O bje c ts 7 .7 1 0 .5 7 .3 5 .3 P a c ifiers 2 .6 3 .4 2 .6 1 .8 N o n P ac i fi ers A l l So f t Plast i c I t em s Sof t Pl as t i c I t em s N ot Food C ont act Sof t Pl as t i c Toys, Teet her s and R at t l es Sof t Pl as t i c Toys Sof t Pl as t i c Teet her s and R at t l es Ot h e r S o f t P l a s t i c I t e ms 5 .1 0 .4 0 .3 0 .2 0 .1 0 .1 0 .1 7 .1 0 .5 0 .4 0 .3 0 .1 0 .2 0 .1 4 .7 0 .4 0 .3 0 .2 0 .2 0 .0 0 .1 3 .5 0 .4 0 .2 0 .1 0 .1 0 .0 0 .1 S o ft P la stic F o o d C o n ta c t It e m s 0 .1 0 .0 0 .1 0 .2 A n a to m y 1 .8 2 .4 1 .7 1 .2 N o n S o ft P la stic T o y s, T e e th e rs a n d R a ttl e s 0 .9 1 .8 0 .6 0 .2 O th e r Item s 2 .1 2 .5 2 .1 1 .7 Sour ce : G r eene , 2002

6-28T ab l e 6 -9. M o u t h i n g T i m e S t ati sti cs for V ariou s O bj ec t s (m i n / h r) A g e G ro u p M e a n (S D ) M e d ia n 9 5 P e rc e n til e th 9 9 P e rc e n til e th Al l I t e ms 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 10. 5 ( 7. 3) 7. 3 ( 6. 8) 5. 3 ( 8. 2) 9 .6 5 .5 2 .4 2 6 .2 2 2 .0 1 5 .6 3 9 .8 2 8 .8 4 7 .8 N o n P ac i fi ers 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 7. 1 ( 3. 6) 4. 7 ( 3. 7) 3. 5 ( 3. 6) 6 .9 3 .6 2 .3 1 3 .1 1 2 .8 1 2 .8 1 4 .4 1 8 .9 1 5 .6 Al l S o f t P l a s t i c I t e ms 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 5 ( 0. 6) 0. 4 ( 0. 4) 0. 4 ( 0. 6) 0 .1 0 .2 0 .1 1 .8 1 .3 1 .6 2 .5 1 .9 2 .9 Sof t Pl as t i c I t em s N ot Food C ont act 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 4 ( 0. 6) 0. 3 ( 0. 4) 0. 2 ( 0. 4) 0 .1 0 .1 0 .0 1 .8 1 .1 1 .3 2 .0 1 .5 1 .8 Sof t Pl as t i c Toys, Teet her s, and Rat t l es 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 3 ( 0. 5) 0. 2 ( 0. 3) 0. 1 ( 0. 2) 0 .1 0 .0 0 .0 1 .8 0 .9 0 .2 2 .0 1 .3 1 .6 Sof t Pl as t i c Toys 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 1 ( 0. 3) 0. 2 ( 0. 3) 0. 1 ( 0. 2) 0 .0 0 .0 0 .0 0 .7 0 .9 0 .2 1 .1 1 .3 1 .6 Sof t Pl as t i c Teet her s and R at t l es 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 2 ( 0. 4) 0. 0 ( 0. 1) 0. 0 ( 0. 1) 0 .0 0 .0 0 .0 1 .0 0 .1 0 .0 2 .0 0 .6 1 .0 Ot h e r S o f t P l a s t i c I t e ms 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 1 ( 0. 2) 0. 1 ( 0. 1) 0. 1 ( 0. 3) 0 .0 0 .0 0 .0 0 .8 0 .4 0 .5 1 .0 0 .6 1 .4

6-29T ab l e 6 -9. M o u t h i n g T i m e S t ati sti cs for V ariou s O bj ec t s (m i n / h r) A g e G ro u p M e a n (S D ) M e d ia n 9 5 P e rc e n til e th 9 9 P e rc e n til e th S o f t P l a s t i c F o o d Co n t a c t I t e ms 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 0. 0 ( 0. 2) 0. 1 ( 0. 2) 0. 2 ( 0. 4) 0 .0 0 .0 0 .0 0 .3 0 .7 1 .2 0 .9 1 .2 1 .9 An a t o my 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 2. 4 ( 2. 8) 1. 7 ( 2. 7) 1. 2 ( 2. 3) 1 .5 0 .8 0 .4 1 0 .1 8 .3 5 .1 1 2 .2 1 4 .8 1 3 .6 N on Sof t Pl as t i c Toys, Teet her s, and Rat t l es 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 1. 8 ( 1. 8) 0. 6 ( 0. 8) 0. 2 ( 0. 4) 1 .3 0 .3 0 .1 6 .5 1 .8 0 .9 7 .7 4 .6 2 .3 Ot h e r I t e ms 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 2. 5 ( 2. 1) 2. 1 ( 2. 0) 1. 7 ( 2. 6) 2 .1 1 .4 0 .7 7 .8 6 .6 7 .1 8 .1 9 .0 1 4 .3 P ac i fi ers 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 3. 4 ( 6. 9) 2. 6 ( 6. 5) 1. 8 ( 7. 9) 0 .0 0 .0 0 .0 1 9 .5 1 9 .9 4 .8 3 7 .3 2 8 .6 4 6 .3
Sour c e : G r e e e ne , 2002

6-30Tabl e 6- 10. Est i m at ed D ai l y M out hi ng Ti m es f or V ar i ous O bj ect s ( m i n/ day) A ge G r oup M ean ( conf i dence i nt erval s) M edi an ( conf i dence i nt erval s) 9 5 th P e rc e n til e ( conf i dence i nt erval s) 9 9 th P e rc e n til e ( conf i dence i nt erval s) N o n P ac i fi ers 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 7 0 .1 ( 60. 6 - 79. 8) 4 7 .4 ( 38. 9 - 57. 1) 3 7 .0 ( 27. 0 - 48. 5) 6 5 .6 ( 52. 3 - 78. 2) 3 7 .0 ( 28. 7 - 49. 9) 2 3 .8 ( 18. 4 - 29. 3) 1 3 4 .4 ( 117. 1 - 153. 2) 1 2 1 .5 ( 85. 2 - 166. 0) 1 2 4 .3 ( 70. 9 - 173. 3) 1 5 3 .1 ( 129. 6 - 180. 6) 1 8 0 .3 ( 123. 6 - 235. 5) 1 6 7 .9 ( 104. 0 - 208. 0) S o f t P l a s t i c I t e ms 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 4 .4 ( 3. 0 - 6. 1) 3 .8 ( 2. 8 - 4. 9) 4 .2 ( 2. 5 - 6. 1) 1 .5 ( 0. 3 - 3. 7) 2 .2 ( 1. 0 - 3. 8) 1 .5 ( 0. 2 - 3. 0) 1 7 .5 ( 12. 2 - 23. 3) 1 3 .0 ( 9. 6 - 17. 8) 1 8 .5 ( 9. 6 - 29. 4) 2 3 .0 ( 16. 2 - 30. 1) 1 8 .9 ( 12. 8 - 23. 8) 2 8 .0 ( 15. 9 - 37. 6) Sof t Pl as t i c Toys 3- 12 m ont hs 12- 24 m ont hs 24- 36 m ont hs 1 .3 ( 0. 7 - 2. 0) 1 .9 ( 1. 2 - 2. 6) 0 .8 ( 0. 3 - 1. 6) 0 .0 ( 0. 0 - 0. 3) 0 .1 ( 0. 0 - 0. 6) 0 .0 ( 0. 0 - 0. 2) 7 .1 ( 3. 9 - 11. 0) 8 .8 ( 5. 6 - 11. 7) 3 .3 ( 1. 4 - 16. 3) 1 0 .5 ( 5. 8 - 13. 7) 1 2 .6 ( 9. 0 - 16. 0) 1 2 .1 ( 2. 0 - 21. 0)
N o t e: B ased on 50 0 0 bo o t st rap sam p l es. Sour c e : G r e e ne , 2002

6-31Table 6-11. Variabil ity in Objects Mouthed for Different Age Groups.
Varia bl e Al l S ub jec ts # 24 Months >24 Months Me an b Me di an 95 % CIc Me an b Me di an 95 % CIc Me an b Me di an 95 % CIc n a (events/h) (events/h) (events/h) n a (events/h) (events/h) (events/h) n a (events/h) (events/h) (events/h) Mo uth- bo dy 18 6 8 2 2- 3 69 10 4 3- 6 11 7 7 1 0.8 -1 .3 Mouth-hand 186 16 11 9-14 69 18 12 9-16 117 16 9 7-12 Mo uth- su rf

ace 18 6 4 1 0.8 -1 .2 69 7 5 3- 8 11 7 2 1 0.9 -1 .1 Mouth-toy 186 27 18 14-23 69 45 39 31-48 117 17 9 7-12 Total event s 186 56 44 36-52 69 81 73 60-88 117 42 31 25-39

a Number of observations. b Arithmetic mean.
c The 95% confidence limits applyto median. Values were calculat ed in logs and converted to original units. Source: Tulve et al ., 2002

6-32T a b le 6 -1 2 . M o u th in g D u ra tion b y A g e G ro u p fo r P a c ifiers , F in g e rs , T o y s, a n d O th e r O bje c ts

I t em M out hed A ge G r oup, s am pl e s i ze ( n ) , and M ou t hi ng D urat i on ( ho urs: m i nu t es: secon ds) 1 -3 m ont hs 3 -6 m ont hs 6 -9 m ont hs 9- 12 m ont hs 12- 15 m ont hs 15- 18 m ont hs 18- 21 m ont hs 21- 24 m ont hs 2 ye ars 3 ye ars 4 ye ars 5 ye ars

n = 9 n = 14 n = 15 n = 17 n = 16 n = 14 n = 16 n = 12 n = 39 n = 31 n = 29 n = 24 D um m y ( Paci f i er ) 0: 47: 13 0: 27: 45 0: 14: 36 0: 41: 39 1: 00: 15 0: 25: 22 1: 09: 02 0: 25: 12 0: 32: 55 0: 48: 42 0: 16: 40 0: 00: 20 Fi nger s 0: 18: 22 0: 49: 03 0: 16: 54 0: 14: 07 0: 08: 24 0: 10: 07 0: 18: 40 0: 35: 34 0: 29: 43 0: 34: 42 0: 19: 26 0: 44: 06

Toys 0: 00: 14 0: 28: 20 0: 39: 10 0: 23: 04 0: 15: 18 0: 16: 34 0: 11: 07 0: 15: 46 0: 12: 23 0: 11: 37 0: 03: 11 0: 01: 53 O t her O bj ect s 0: 05: 14 0: 12: 29 0: 24: 30 0: 16: 25 0: 12: 02 0: 23: 01 0: 19: 49 0: 12: 53 0: 21: 46 0: 15: 16 0: 10: 44 0: 10: 00 N ot R ecor ded 0: 00: 45 0: 00: 24 0: 00: 00 0: 00: 01 0: 00: 02 0: 00: 08 0: 00: 11 0: 14: 13 0: 02: 40 0: 00: 01 0: 00: 05 0: 02: 58 Tot al ( al l obj ect s) 1: 11: 48 1: 57: 41 1: 35: 11 1: 35: 16 1: 36: 01 0: 15: 13 1: 58: 49 1: 43: 39 1: 39: 27 1: 50: 19 0: 50: 05 0: 59: 17

Sour ce : Sm i t h and N or r i s , 2003

6-33Ta bl e 6 -13 . I nd oo r Mo ut hi ngFr eq ue nc y (C on tac ts/Hou r). a A g e (m o n th s) n St at i s t i c H ands Tot al non- di e t ar y b

# 24 1 73.5 84.8 >24 8 Mean 13.9 22.7 Median 13.3 19.5 Range 2.2 - 34.1 2.8 - 51.3 All ages c 9 Mean 20.5 29.6 Median 14.8 22.1 Range 2.5 - 70.4 3.2 - 82.2

aSh ow s d ata fr om ch ild ren wh o h ad m orethan 1 5 minutes in v iewind oo rs. b Al l ob jec t/s urf acecat eg ori es i nc lud ed : an im al, clo the s/t ow els , f ab ric , h an ds , m eta l, n on -di etary w ate r, paper/wrapper , plastic , skin, toys, veget ation/gr ass, and wood.
c A g es 1-6 y ears. Sour c e : A uY e ung e t a l

. , 2004

6-34Ta bl e 6 -14 . Ou td oo r Mo ut hi ngFr eq ue nc y (C on tac ts/Hou r). A g e (m o n th s) n St at i s t i c H ands Tot al non- di e t ar y a
# 24 8 Mean 13.0 20.4 Median 7.0 13.9 Range 1.3 - 47.7 6.2 - 56.4 >24 30 Mean 11.3 17.7 5 percenti le

th 0.2 0.6 25 percenti le th 4.7 7.6 Median 8.6 14.6 75 percenti le th 14.8 22.4 95 percenti le th 27.7 43.8 99 percenti le th 39.5 53.0 All ages c 38 Mean 11.7 18.3 5 percenti le

th 0.4 0.8 25 percenti le th 4.4 9.2 Median 8.4 14.5 75 percenti le th 14.8 22.4 95 percenti le th 31.5 51.7 99 percenti le th 47.6 56.6

aAl l ob jec t/s urf acecat eg ori es i nc lud ed : an im al, clo the s/t ow els , f ab ric , h an ds , m eta l, n on -di etary w ate r, paper/wrapper , plastic , skin, toys, veget ation/gr ass, and wood.
c A g es 1-6 y ears. Sour c e : A uY e ung e t a l

. , 2004

6-35Ta bl e 6 -15 . I nd oo r Mo ut hi ngCo nt ac t D ur ati on (Mi nu tes /Ho ur ). a A g e (m o n th s) n St at i s t i c H ands Tot al non- di e t ar y b

# 24 1 10.7 11.1 >24 8 Mean 0.7 1.2 Median 0.7 0.9 Range 0 - 1.8 0.1 - 3.6 All ages c 9 Mean 1.8 2.3 Median 0.7 0.9 Range 0 - 10.0 0.1 - 10.5

aSh ow s d ata fr om ch ild ren wh o h ad m orethan 1 5 minutes in v iewind oo rs. b Al l ob jec t/s urf acecat eg ori es i nc lud ed : an im al, clo the s/t ow els , f ab ric , h an ds , m eta l, n on -di etary w ate r, paper/wrapper , plastic , skin, toys, veget ation/gr ass, and wood.
c A g es 1-6 y ears. Sour c e : A uY e ung e t a l

. , 2004

6-36Ta bl e 6 -16 . Ou td oo r Mo ut hi ngCo nt ac t D ur ati on (Mi nu tes /Ho ur ). A g e (m o n th s) n St at i s t i c H ands Tot al non- di e t ar y a
# 24 8 Mean 2.7 3.1 Median 0.4 0.8 Range 0 - 14.7 0.2 - 15.0 >24 30 Mean 0.4 0.7 5 pe rce nti le

th 0 0 25 percenti le th 0.1 0.2 Median 0.2 0.6 75 percenti le th 0.4 1.0 95 percenti le th 1.2 2.1 99 percenti le th 2.2 2.5 All ages c 38 Mean 0.9 1.2 5 pe rce nti le

th 0 0 25 percenti le th 0.1 0.2 Median 0.2 0.6 75 percenti le th 0.6 1.2 95 percenti le th 2.6 2.9 99 percenti le th 11.2 11.5

aAl l ob jec t/s urf acecat eg ori es i nc lud ed : an im al, clo the s/t ow els , f ab ric , h an ds , m eta l, n on -di etary w ate r, paper/wrapper , plastic , skin, toys, veget ation/gr ass, and wood.
c A g es 1-6 y ears. Sour c e : A uY e ung e t a l

. , 2004

6-37Tabl e 6- 17. V i deot aped M out hi ng and Food- handl i ng A ct i vi t y as M edi an H our l y Fr equenc y ( C ont act s/ H our ) and M edi an Du r a t i o n ( % o f T a p e T i m e ) ( M e a n ± S D)

A g e N H a n d to m o u th Fr equenc y D ur at i on O bje c t t o M o u th Fr equenc y D ur at i on Food Fr equenc y D ur at i on I nf ant 1 3 14 ( 19. 8 ± 14. 5) 3. 0 ( 4. 6 ± 6. 0) 18. 1 ( 24. 4 ± 11. 6) 3. 1 ( 4. 0 ± 2. 4) 10. 0 ( 10. 8 ± 9. 0) 3. 9 ( 7. 0 ± 7. 4)

1 y e a r o ld 1 2 13. 3 ( 15. 8 ± 8. 7) 2. 2 ( 3. 8 ± 7. 0) 8. 4 ( 9. 8 ± 6. 3) 1. 3 ( 1. 6 ± 1. 2) 16. 1 ( 17. 2 ± 14. 0) 5. 2 ( 6. 8 ± 5. 8)

2 y e a r o ld 1 8 9. 9 ( 11. 9 ± 9. 3) 1. 3 ( 1. 5 ± 1. 3) 5. 5 ( 7. 8 ± 5. 8) 0. 9 ( 1. 3 ± 1. 1) 13. 9 ( 14. 7 ± 10. 9) 5. 6 ( 5. 0 ± 3. 8)

Pr es chool 9 19. 4 ( 22. 1 ± 22. 1) 1. 5 ( 3. 1 ± 3. 4) 8. 4 ( 10. 1 ± 12. 4) 1. 9 ( 3. 0 ± 3. 9) 10. 2 ( 15. 7 ± 11. 8) 5. 6 ( 4. 7 ± 2. 6)

Sour ce: B l ack et al

. ( 2005)

6-38Tabl e 6- 18. Sum m ar y of St udi es on M out hi ng B ehavi or
St udy Popul at i on Si ze Popul at i on St udi ed G r oot etal

. 1998 42 3- 36 m ont hs i n N et her l ands c h ildre n fro m w e ll e d u c a te d p a re n ts R ee d et al. 19 9 9 3 0 2 0 ch i l d ren 3-6 ye ars 1 0 ch i l d ren 2-5 ye ars D ay c ar e a nd r es i dent i al s et t i ngs Z art ari an 1 99 7 an d 19 98 4 2.5- 4.2 years ch i l d ren of farm w o rke rs D avis 19 95 92 10

- 60 m on t hs W a sh in g to n S ta te S t an ek et al. 19 9 8 3 5 5 1 -6 y ea rs p riv a te m e d ic a l clin ic S p rin g fie ld , M a ss a c h u se tts Jube r g etal

. , 2001 Phase 1 & 2: 217 Phase 3: 168 P h a se 1 & 2 : l e ss th a n 3 y rs o ld Phase 3: 3 t o 18 mont hs W es t er n N ew Y or k - r es ear ch c ent er and da y ca re F ree m an et al. , 2 0 0 1 1 6 8 3 -12 ye ars U rb a n a n d ru ra l are a s o f M in n e so ta G r eene , 2002 169 3 - 36 mont hs C hi cago and H oust on m et r opol i t an a r ea Tul ve e t al

. , 2002 72 10- 60 m ont hs I ndoor hom e e nvi r onm ent S m i t h an d N o rr i s, 20 0 3 2 3 6 A g es 1 m o n t h t o 5 y ea rs i n - h o me N et her l ands A u Y eu n g et al. , 2 0 0 4 3 8 A g es 1-6 ye ars I ndoor and out door hom e e nvi r onm ent S a n F ra n c isc o p e n in su la B l ack et al

. , 2005 52 7- 53 m ont hs M i d- R i o G r ande V al l ey A g ric u ltura l co m m u n ity

6-39Tab le 6- 19

. S umm ary o f M outh in g F req uen cy Data Ag e ( m onth s) Me an Mo uthi ngF req uen cy/Tim e Po pu lat io n S ize Ref ere nce Hand -to -m outh Ob jec t-t o- Mo uth T ot al 10-60 55 min/day EPA analy sis based on Davis 1995 2.5-4.2 y ears 9 contacts/hr 4 Zartari an 1997 3- 6 6-12 12-18 18-36 3 7 m i n/ d ay 44 m in/d ay 16 m in/d ay 9 min/d ay 5 14 12 11 Groot et al. 1998

2-6 ye ars 9.5 contact s/hr 16.3 contact s/hr 25.8 contact s/hr 30 Reed et al. 1999 3- 4 years 5- 6 years 7- 8 years 10 -1 2 years 4 contacts/hr 8 contacts/hr 5 contacts/hr 4 contacts/hr 6 contacts/hr 1 contacts/hr 1 contacts/hr 1 contacts/hr 10 contacts/hr 9 contacts/hr 6 contacts/hr 5 contacts/hr 3 7 4 5 Freeman et al. 2001

0-18 18-36 7 0 m i n/ d ay a 5 6 m i n/ d ay a 146 40 Juberg et al, 2001

3-12 12-24 24-36 2 .4 m i n/hr ; 2 6 m i n/ d ay b 1 .7 m i n/hr ; 1 8 m i n/ d ay b 1 .2 m i n/hr ; 1 2 m i n/ d ay b 70 m in/d ay 48 m in/d ay 37 m in/d ay 64 60 45 Greene, 2002

<24 18 contacts/hr 62 contacts/hr 81 ± 7 contact s/hr 28 Tulve et al. 2002 >24 16 contacts/hr 26 contacts/hr 42 ± 4 contact s/hr 44

6-40c Tab le 6- 19

. S umm ary o f M outh in g F req uen cy Data Ag e ( m onth s) Me an Mo uthi ngF req uen cy/Tim e Po pu lat io n S ize Ref ere nce Hand -to -m outh Ob jec t-t o- Mo uth T ot al 1- 3 3- 6 6- 9 9-12 12-15 15-18 18-21 21-24 2 years 3 years 4 years 5 years 5 0 m i n/ d ay c 9 6 m i n/ d ay c 7 7 m i n/ d ay c 9 8 m i n/ d ay c 3 6 m i n/ d ay c 3 9 m i n/ d ay c 8 0 m i n/ d ay c 1 1 3 m i n/ d ay c 1 4 8 m i n/ d ay c 1 9 9 m i n/ d ay c 1 7 1 m i n/ d ay c 5 4 3 m i n/ d ay c 29 m in/d ay 13 2 min/d ay 25 1 min/d ay 15 6 min/d ay 15 7 min/d ay 13 6 min/d ay 99 m in/d ay 14 2 min/d ay 30 4 min/d ay 17 9 min/d ay 96 m in/d ay 64 m in/d ay 7 9 m i n/ d ay c 2 2 8 m i n/ d ay c 3 2 8 m i n/ d ay c 2 5 4 m i n/ d ay c 1 9 3 m i n/ d ay c 1 7 5 m i n/ d ay c 1 7 9 m i n/ d ay c 2 5 5 m i n/ d ay c 4 5 2 m i n/ d ay c 3 7 8 m i n/ d ay c 2 6 7 m i n/ d ay c 6 0 7 m i n/ d ay c 9 14 15 17 16 14 16 12 39 31 29 24 Smith and Norris 2003

# 24 2- 6 7 contacts/hr 1 2 m i n/ d ay b 12 contacts/hr 2 m i n/ d ay b 1 contact/hr 1 m i n/ d ay b 8 contacts/hr 1 m i n/ d ay b 9 contacts/hr 1 2 m i n/ d ay b 20 contacts/hr

3 m i n/ d ay b 9 38 AuYeung et al., 2004 d

7-12 13-24 25-36 37-53 20 contacts/hr 16 contacts/hr 12 contacts/hr 22 contacts/hr 24 contacts/hr 10 contacts/hr 8 contacts/hr 10 contacts/hr 44 contacts/hr 26 contacts/hr 20 contacts/hr 32 contacts/hr 13 12 18 9 Black et al. 2005

a D oer s on ly from Ta bl e 6 -8 ; t ot als ca lcu lat ed by ad di ngal l n on pa cif ier

ob jec ts b D aily mo uthi nges tim ate d u si ng10 ho ur s aw akefo r c hi ld ren un der 2 years ol d and 10 .7 ho ur s aw akefo r c hi ld ren 2- 3 years ol d f ro mGree ne (2 00 2)

. Includes finger/thumb sucking d In clu des in do or an d o ut do or data.

6-41T ab l e 6 -20

. S u m m ary of R ec o m m en d ed V alu es for T o t al M o u t h i n g T i m e (m i n u t es pe r da y ) a

A ge M ean M out hi ng Ti me ( m i n/ day) Sour ce
b irth to < 1 m o n th n o d a ta n o d a ta a v a ilab le

1 t o <3 m ont hs no dat a no dat a a vai l abl e ( Sm i t h and N or r i s, 2003 w er e notus ed be caus e t hum b/ f i nger suck i ng had a si gn i f i can t ef f ect on resul t s) 3 t o <6 m ont hs 27 We ig h te dm e a n o f: G r oot etal

. , 1998 and R eed et al

. 1999 6 t o <12 m ont hs 65 We ig h te dm e a n o f: G r oo t et al

. , 199 8 an d G r een e, 200 2 (used 3-12 m on t hs) 1 t o <2 year s 39 We ig h te dm e a n o f: G r oo t et al

. , 199 8 (used 12

- 18 m on t hs) G r eene , 2002 A uY eung e t al

. , 2004 ( use d # 24 m on t hs) 2 t o <3 year s 32 We ig h te dm e a n o f: G r oot etal

. , 1998 ( use d 18- 36 m ont h gr oup) G r eene , 2002 3 t o < 6 ye ars no dat a no dat a ava i l able ( Sm i t h an d N orr i s ( 20 03 ) data w ere not used b ecau se t hu m b/ f i ng er suck i ng had a si gn i f i can t ef f ect on resul t s) 2 t o 6 yea r s 7 A uY eung e t al

. , 2004

a E xcludes m ou t hi ng pacif i ers

6-42T ab l e 6 -21

. S u m m ary of R ec o m m en d ed V alu es for M o u t h i n g F req u en cy (co n t ac t s p er h o u r)

A ge M ean M out hi ng Fr equenc y R ef er ence H and- t o- M out h O bj ect
- t o- M out h Tot al b irth to < 1 m o n o d a ta n o d a ta n o d a ta

1 to < 3 m o n o d a ta n o d a ta n o d a ta 6 t o <12 m o 20 cont act s/ hr 24 cont act s/ hr 44 cont act s/ hr B l ack et al

. 2005 1 t o <2 year s 16 cont act s/ hr 38 cont act s/ hr 54 cont act s/ hr We ig h te dm e a n o f: T u lv e e t al., 2 0 0 2 , A u Y e u n g e t al, 2004, and Bl ack et al

. , 2005 2 t o <3 year s 12 cont act s/ hr 8 cont act s/ hr 20 cont act s/ hr H and- t o- m out h i s w ei ght ed mean o f Z a rta ria n 1 9 9 7 a n d B la c k e t al. 2005 O bj ect
- t o- m out h i s bas ed on Bl ack et al

. 2005 Tot al i s bas ed on Bl ack et al

. 2005 2 t o 6 yea r s 12 cont act s/ hr 8 cont act s/ hr 20 cont act s/ hr A uY eung e t al , 2004 3 t o < 6 ye ars 1 4 co n t ac t s/hr 1 9 co n t ac t s/hr 3 2 co n t ac t s/hr We ig h te dm e a n o f: R e e d e t al. 1 9 9 9 , F re e m a n e t al. 2001, Tul ve e t al

. 2002, and Bl ack et al

. 2005

6 t o < 11 year s 4 cont act s/ hr 1 cont act s/ hr 5 cont act s/ hr B as ed on w ei ght ed mean of 7- 8 and 10- 12 yea r s ol d f r om Fr eeman et al

. 2001 1 yea r 2 ye ars 3 ye ars 4 ye ars 5 ye ars 6 ye ars 3 t o < 6 ye ars C ont actf r equenc y w i t h s peci f i c obj ect s and s ur f ace s ( per cent doi ng dai l y, w eekl y, and mont hl y) St anek et al

. , 1998 ( Tabl e 6- 3)

6-43Tabl e 6- 22. C onf i dence i n M out hi ng B ehavi or R ecomm endat i ons
C onsi der at i ons R at i onal e R at i ng S tu d y E le m e n ts Peer R evi ew Ther e a r e e l even studi es ; ni ne of t he s t udi es ar e f r om peer - r evi ew ed j our nal s; one i s an EPA ana l ysi s of r aw data f r om a con t r act or' s r epo r t t o E PA and one i s a g o v ern m en t rep o rt H i gh

A cce ss i bi l i t y St udi es i n j our nal s have w i de c i r cul at i on. C on t r ac t or ' s r ep or t on l y a va i l ab l e t hr ou gh EPA M edi um
R e p ro d u c ib ili ty C a n fo llow a n a ly sis , b u t ca n n o t rep ro d u c e th e d a ta unl es s r aw dat a a r e pr ovi ded. M edi um
Focus on f act or of I nt er es t St udi es f ocus ed on mout hi ng beha vi or as w el l as ot her han d co nt act s. H i gh

D at a pe r t i nent t o U

. S. A l l but one of t he s t udi es w er e c onduct ed i n t he U

. S. H i gh Pr i m ar y dat a A nal yse s w er e done on pr i m ar y dat a. EPA di d t he anal ysi s of t he r aw dat a f r om D avi s et al

. ( 1995) and c o m p o site d d a ta fro m th e S ta n e k e t al. (1 9 9 8 ) stu d y to con f orm t o st and ardi zed age g r ou pi ng s. H i gh

C ur r ency R ece nt s t udi es w er e e val uat ed. H i gh A dequac y of dat a c ol l ect i on per i od D at a w er e c ol l ect ed f or a pe r i od of s ever al days , not eno ug h t o repr esent season al vari at i on s. M edi um
V a lidity o f A p p ro a c h M e a su re m e n ts w e re m a d e b y o b se rv a tion m e th o d s. B o th sur veys and vi deot api ng w er e us ed. V i deot api ng t echni ques m ay be m or e r el i abl e, but r es our ce i nt ens i ve. M edi um

R epr es ent at i venes s of t he popul at i on D ata for so m e a g e g rou p s w ere no t av ail ab l e. A n effort w as m ade t o cons i der age and ge nder , but s am pl e s i zes w er e s m al l ; SES f act or s not eva l uat ed Low

C har act er i zat i on of var i abi l i t y A n ef f or t w as m ade t o cons i der age and ge nder , dat a f or i nf ant s and ol der chi l dr en a r e f ai r l y l i m i t ed. Low
Lack of bi as i n s t udy des i gn Subj ect s w er e s el ect ed f r om vol unt eer s. M edi um M eas ur em ent er r or M eas ur i ng chi l dr en' s behavi or i s di f f i cul t and s om ew hat subj ect i ve a nd depe nds on t he e xper i ence of t he o b se rve r. M edi um

O th e r E le m e n ts N um ber of s t udi es El even studi es w er e e val uat ed M edi um A gr eement bet w een r es ear cher s Ther e i s gener al agr eement among t he r es ear cher s. H i gh O ver al l R at i ng A l t hough t her e a r e e l even studi es , f or s om e of t he a ge gr oups sa m pl e s i ze w as s m al l , var i abi l i t y i n t he popul at i on ca nnot be a ss es se d. V ar i at i on i n beha vi or due t o s eas ons cannotbe e val uat ed. M eas ur i ng c h ildre n ' s b e h a v io r is d ifficu lt. L ow

6-44