ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 1 **F I**  **N A**  **L T**  **E C**  **H N**  **I C**  **A L**  **M E**  **M O**  **R A**  **N D**  **U M** 



# Thre **s ho**  **ld V**  **a l**  **ue s for S**  **e le**  **niu m**  **in Gr**  **e a**  **t**

**S a**  **lt L**  **a ke**  **:**

**Se le**  **c tio**  **ns by**  **th e**  **S ci**  **e nce**  **P a**  **n e**  **l**

**PR EPA**  **R ED**  **F OR**  **:** Gre at Sal t La k e Sc i ence P a nel

**PR EPA**  **R ED**  **B Y:**  Har ry Ohl endorf

**C OPI**  **ES:** J ef f D enBle y k er

Earl By ron

Gary Santol o

D an Moore

Pri nci p al I nve s ti g ator s

**D A**  **T E:**  F eb ruary 28, 2007

**PR OJEC**  **T N**  **U M**  **B ER**  **:** 341055. P P. Q C

The p urp o s e of t his tec hn i c al m e m orandu m i s to p rovi de a s um m ary and doc um entation

of the Sc i ence P anel’s di s c u s s i on s rel ati ve to to xic i ty thre s hold s f or e xp o s ure of b i rds to

s el enium at the Gre at Sal t La k e

. I t i s g eneral l y rec og nized t hat t he m os t s i g nif i c ant

exp os ure of b i rds oc c urs throu g h their di et, and th at the b es t­ doc um e nted a nd m os t

read i l y

­ m onito red ef f ec ts are tho s e o n reprod ucti ve s ucc es s ( p arti c ularl y eg g hatchab i l i ty )

. Thus, mu c h of the f oc us of thi s tec h nic al m em ora n dum i s o n tho s e exp o s ure s and

endp oi nts, b ec aus e they c an b e m o s t read i l y a p p l i ed tow ard e s tab l i s hm e nt of a s i te­ s p ec i f i c

w ater qu al i ty s ta ndard f or s el eniu m i n the open w aters of the Gre at Sal t La k e

.

Bef ore the Sc i ence P anel m eeti ng on No vem b er 29

­ 30, 2006

, I p repared a tec hn i c al

m em orand um ( Sub ject: Thres hold Val ue s f or Sel e nium i n Gre at Sal t La k e; dated

No vem b er 28) to p rovi de the f ol l ow i ng :

· a s um m ary of p ot ential thre s hold val ues ide ntif i ed b y Sc i ence P anel m em b ers f or

c ons i der ati on i n e s tab l i s hin g a w ater q uali ty s tand ard for s el eniu m i n the ope n w ater s of

the Gre at Sal t La k e, and

· s up p orti ng doc um e ntation and l i terature p rovi de d b y Pan el m em b er s to b e u s ed as the

b as i s of di s c ussion b y the Pa nel.

Bi l l Adam s

, An ne F ai rb rother, There s a Pres s er, an d J oe Skor up a p rovi ded in p ut c onc erni ng

thres hold val ues to b e c ons i der ed and s ent s up p or ti ng l i terature ( ei ther as c i tati ons or co p i es

of p ubl i c ati ons )

, i n addi ti on to p rovi di ng their vi ew s on the thre s hold val ue s the m s el ve s

. The entir e Pan el di s c ussed t hat m ateri al a nd rel ate d i nfor m ati on f ro m other s ourc es on

No vem b er 30. F rom the avai l ab l e i nfor m ati on, t he Pan el narrow ed th e ran g e s of v al ues for

b i rd die ts and eg g s to t hos e l i s ted i n Tab l es 1 a nd 2 ( Attachm e nt A [ tab l es m odi f i ed f rom the

c omp i l ati on of f i el d and l ab orato ry data p re s ented i n Tab l e 15 of Pre s s er and Luo m a, 2006] )

and the n i dentif i ed “w orkin g v al ues ” f or th e ran g es of ac c ep tab l e s el eniu m c onc entrati on s

i n b i rd die ts a nd i n b i rd eg g s ( thos e s haded i n the tab l es )

. I t i s u nders tood that the val ue s

w i l l l i k el y b e ref i ned duri ng f utu re p has e s of w ork ( i ncl uding c ons i der ati on of s i te­ s p ec i f i cT HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 2 data c urrently b ei ng g enerat ed b y the Gre at Sal t L ak e re s earc h ef f ort) and di s c u s s i on rel ated

to es tab l i s hin g a s i te­ s p ec i f i c s tandard f or Great Sa l t Lak e.

A p revi ou s draf t of t his tec h nic al m em ora ndu m ( dated D ec e m b er 8) p rovi ded a b ri ef

s um m ar y of t he t hres hold val ue s t hat w ere s el ec te d b y t he Pan el d uring thos e di s c u s s i ons

. F or bo th d i et and eg g s

, the ra ng e s of s el eniu m c on c entrati ons s el ec ted b y the Pan el are t he

l ow er an d u p p er 95 p erc ent c onfi denc e i nt erval s ( 95% C I s ; al s o ref err ed to as the 5 p erc ent

l ow er conf i denc e l i m i t [ LCL] and the 95 p erc ent u p p er conf i denc e l i m i t [ UC L] ) f or t he m ean

s el enium c onc entrati on t hat i s a s s oc i ated w i th a 1 0 p erc ent red ucti on ( i

. e

. , the 10 p erc ent

ef f ec t c onc entrati on or EC 1 0 ) i n the hatch ab i l i ty of m al l ard eg g s

. Tho s e val ues wer e re p orte d

b y Ohl endorf ( 2003)

, b as e d on the anal y s i s of data f rom s i x l ab orato ry s t udies ( He i nz et al

. 1987, 1989; He i nz a nd Ho f f m a n 199 6, 1998 ; Stanl e y et al

. 1994, 1996)

. E s s e ntial l y

, t here i s

95 p erc ent c onfi denc e that the m ea n di etar

y or eg g s el enium c onc entrati on that c aus e s a

10 p erc ent red ucti on of eg g hatchab i l i ty i s w i thin t he i dentif i ed ran g es

, w hic h are il l us trated

i n the f i g ures b el ow

.

The Pa nel ag reed b y c ons e nsus that the 95% C I s o n m e an seleni u m c onc entrati on s i n

m al l ard die t and eg g s a s s oc i ated w i th the EC 1 0 f or eg g hatchab i l i ty w ould b e re as on ab l y

p rote c ti ve f or bi rds ne s ti n g at the Gre at Sal t Lak e

, and that the ran g es of val u es repre s ented

b y the 95% C I s i ncl uded t he c onc entrati on s p ropo s ed b y vari ou s P anel m em b ers f or

c ons i der ati on. Rational e s u p p orti n g s el ec ti on of th e 95% C I s i s p rovi ded b y t he p revi ous

tec hn i c al m em orand um ( dated Nove m b er 28) and throu g h di s c ussion at t he P anel m eeti ng

.

Pan el m em b ers p rovi ded c omm e nts on the D ec e m

b er 8 draf t ver s i on of this tec hn i c al

m em orand um s um m ari zi ng thre s hold val ue s ( Att ac hm ent B)

, and Bi l l Ada m s p rovi ded

f urth er data analy s e s of ef f ec t l evel s i n di et s a nd e g g s of m al l ards that are incl uded i n thi s

revi s ed draf t. Addi ti onal co n s i der ati ons and qu al i f i c ati ons ab out the s el ec ted di etary and

eg g c onc entrati ons are p rese nted b el ow i n the D i s c us s i on s ec ti on

.

All c onc entrati ons i n b i rd die ts or e g g s m entio ned b el ow are ex p res s ed o n dr

y

­ w ei g ht b a s i s

.



## Sel **e niu**  **m in**  **B ird**  **D ie**  **t s** 

The di etary s el eniu m E C 1 0 f or m al l ards w as report ed as 4. 87 m g / k g

, w i th 95 % C I s of 3. 56 to

5. 74 m g /k g b a s ed on reprod ucti ve toxic i ty ( eg g h atc habi l i ty ) ( Ohl endorf 2003)

. The EC 1 0 of

4. 87 m g /k g w a s e s ti m ated b y f i tti ng a l og i s ti c re g ress i on m odel ( F i g ure 1)

. I t s hou l d b e

noted, howeve r, that the m al l ard s tudie s us ed a “ dry di et” t hat had ab ou t 10 p erc ent

m oi s ture

. O hlendor f ( 2003) u s ed the reported di etary seleni um c onc entrati ons w i thou t

adju s t m ent f or th at m oi s ture c onten t

, b ut an u p w a rd adj u s tm e nt of the val ues (b y

11 p erc ent) w o uld be a p p ropri ate to ac c oun t f or t h e m oi s t ure c onte nt of the duck di et.

I n Adam s et al

. ( 2003)

, hoc k e y

­ s ti c k regre s s i on w a s u s ed to m odel rel ati ons hips b etw een e g g

s el enium c onc entrati ons and adver s e ef f ec ts i n or der to der i ve to xic i ty thre s hold s

, s uch a s

EC 1 0 val ue s

. Ho c k ey

­ s ti c k re g res s i on i s a m odel th at ha s b een u s ed el s ew here to def i ne a

thres hold w hen an underl y i n g b ac k g round l evel o f resp o ns e i s un rel ated to t he do s e ( s ee

Adam s c om m ent s i n Attach m ent B)

. Thu s

, s uch a m odel m a y b e rel evant to na turall y

oc c urri ng el em ent s t hat ar e e s s e ntial to b i rds and a w i de vari ety of other orga nis m s and

p arti c ularl y usef ul f or eleme nts suc h a s s el eniu m

, w hic h has a narr ow ran g e b etw een l evel s

that are es s ential a nd t hos e that are t o xic to b i rds s o that vari ance arou nd t he i nfl ec ti on

p oi nt ( thre s hold ) i n the m odel i s s m al l

. A s s hown i n F i g ure 2 b el ow

, a thres hold c l earl yT HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 3 **0 %**  **1 0**  **% 2**  **0 %**  **3 0**  **% 4**  **0 %**  **5 0**  **% 6**  **0 %**  **7 0**  **% 8**  **0 %**  **9 0**  **% 1**  **0 0**  **%**

**0 .1**  **1 1**  **0 1**  **0 0** 

**Die t**  **a ry**  **S e** 

**, m**  **g/k g d**  **ry w**  **t**

**. D** **uc k** **li ng** **M ort** **a li** **t y** **, %**  E m p i r ic a l d a ta

P r e d icte d m o r ta li ty

9 5 % co n f ide n c e in te r va l

In f lect ion p o i n t = 3 .9 m g /kg

E C 1 0 ( p r e d ict e d ) = 4 .4 m g /k g

E C 1 0 ( L C L ) = 3 .8 m g / kg

E C 1 0 ( U CL) = 4 .8 m g /k g

**Fi gure**  **2**

**. H**  **oc k**  **e y**  **s t**  **i c**  **k r**  **e gr**  **e s**  **s i**  **on of l**  **a bora**  **t ory**  **m a**  **ll a**  **rd duc k**  **l i**  **ng**

**m ort**  **a li**  **t y**  **v e**  **rs us**  **di e**  **t a**  **ry s**  **e l**  **e n**  **i um** 

**.**T HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 4 ap p ear s to exis t w hen di etary s el eni um i s p l otted vers u s duc k l i ng m ortal i ty ( w hic h

i nco rporated th e c um ulati ve ef f ec ts of f erti l i zati on s ucc es s and hatchab i l i ty )

. The i nfl ec ti on

p oi nt oc c urs at a di etary s el e nium c onc entrati on o f 3. 9 m g /k g

. ( The D i s c u s s i on s ec ti on

b el ow des c ri b es un c ertai nty arou nd th e i nfl ec ti on p oi nt. ) T he p red i c ted EC 1 0 i s 4

. 4 m g /k g ( ju s t s l i g htl y ab ove the i nfl ec ti on p oi nt) and the 95 % C I around the p red i c ted E C 1 0 ran g e s

f rom 3. 8 to 4. 8 m g / k g

. Th e p red i c ted EC 1 0 of 4. 4 m g /k g i s s l i g htly l ow er t han Ohl endorf ’ s ( 2003) EC 1 0 of 4. 9 m g / k g

, a nd t he 95 % C I i s narro w er u s i n g hoc k ey s ti c k regre s s i on tha n

w hen u s i ng l og i s ti c re g res s i on.



## Sel **e niu**  **m in**  **B ird**  **Egg s** 

Si m i l ar to the di etary v al ues cal c ulated by O hlend orf ( 2003) f or rep rod ucti ve to xic i ty f or

m al l ards, th e EC 1 0 i n e g g s w a s re p orte d a s 1 2. 5 m g /k g

, w i th 95% C I s of 6

. 4 to 16

. 5 m g /k g ( F i g ure 3)

. The E C 1 0 of 12

. 5 m g /k g w a s e s ti m ated b y f i tti ng a l og i s ti c re g res s i on m odel to

the res ults of the s i x l ab orato ry stu di e s w i th m al l a rds

.

As noted i n Tab l e 2

, the E C 1 0 f or du c k l i ng m ortal i ty

, as reported i n Adam s et al

. ( 2003)

,

rang ed f ro m 12 to 16 m g / k g ( s ee Ada m s c om m en ts i n Attach m ent B)

. Thes e E C 1 0 val ue s are

b as ed on a s y nth e s i s of l ab orato ry stu di e s i n w hic h the f i nal end p oi nt w a s d uckli ng m ortal i ty

( the s a m e ef f ec ts data u s ed i n the di etary EC 1 0 eva l uation w i th hoc k ey

­ s ti c k regre s s i on ab ove)

and the ran g e of EC 1 0 val ues refl ec ts di f f erent s tati s ti c al ap p roac he s f or analyzin g t he dat a.

An ada p tati on f rom F i g ure 3 i n Ada m s et al

. ( 2003 ) i s p rovi ded bel ow ( F i g ure 4)

, w i th the

95% C I i ncl uded. A s s hown

, t he i nfl ec ti on p oi nt o c c urs at a n e g g s el enium c onc entrati on

of 9. 8 m g /k g

, w i th a p red i c ted E C 1 0 c om p arab l e to that der i ved b y Ohl endorf ( 2003)

. ( See D i s c u s s i on f or co m m ent s c onc erni n g un c ertai nty around the i nfl ec ti on p oi nt. ) Ho w ever,

the 95 % C I u s i ng hoc k e y

­ s ti c k regre s s i on i s m uch narrow er (9. 7 to 13

. 6 m g /k g ) tha n t hat

der i ved b y Ohl endorf us i n g l og i s ti c regre s s i on ( 6. 4 to 16

. 5 m g /k g )

. Gi ven t hat there i s a c l ear

eg g

­ s el eni um thre s hold at w hic h ef f ec ts b e g i n to b e ob s erved

, a un i m odal m odel

, s uch as

l og i s ti c regres s i on, m ay res ult i n e xag g erated c onfi denc e i nterval s

, p arti c ularl y i n the tai l s

.



## D **is c**  **u s**  **s ion** 

Addi ti onal discus s i on i s p resen t ed b el ow c onc erni ng t he b a s i s f or s el ec ti on of thres hold

val ues

, u ncer tai nty s urro un di ng the hoc k e y

­ s ti c k regres s i on i nfl ec ti on p oi nt s

, hor m eti c

ef f ec ts of s el eniu m

, and other q uali f i c ati ons and p oi nts di s c u s s ed d uring the Pan el m eeti n g

i n No vem b er, as ref l ec ted i n c om m ent s f rom Pan e l m em b er s ( Attach m ent B)

.



### B **as i**  **s for S elect**  **i on**  **of Threshold V**  **a l**  **ues**

The Sc i ence P an el c an c hoo s e a s c i entif i c al l y

­ b as ed thres hold val ue or acc ep tab l e

“b enchm ark” c onc entrati on b a s ed o n t he c on s en s us c onfi denc e l i m i t s de s c ri b ed b y an al y s i s

of avai l ab l e data ( p rese nted ab ove)

, b ut ulti m atel y

, a c hoic e of n um b ers f rom w i thin the

c ons en s us conf i denc e l i m i ts f or reg ulator y p ur p os es i s not a s c i entif i c dec i s i on. C hoic es of a

s p ec i f i c nu m b er or n um b ers f rom w i thin tho s e c o nfi denc e rang e s are p hil os oph i c al /legal

dec i s i ons th at de p end on how p rec autionary the S tate of Ut ah w a nts to b e ( a m atter of

p hil os oph y ) a nd o n how m uch p otential f or legal l i ab i l i ty the St ate i s c omfor tab l e w i th

exp os i n g i t s el f to. The k e y dec i s i on the State m u s t m ak e i s w heth er they w ant to re g ulate to

a “NE C ” ( no ef f ec ts c onc entrati on, w hic h i s not th e s a m e a s a NO E C [ no ob s erved ef f ec tsT HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 5 **0 %**  **1 0**  **% 2**  **0 %**  **3 0**  **% 4**  **0 %**  **5 0**  **% 6**  **0 %**  **7 0**  **% 8**  **0 %**  **9 0**  **% 10**  **0 %** 

**0 .1**  **1 1**  **0 1**  **0 0** 

**E gg**  **S e** 

**, mg**  **/k g d**  **ry w**  **t**

**. Du** **c kl** **ing Mo** **rta lity** **, %** E m p i r i c a l da ta

P r ed i c t ed m o r ta l i ty

9 5% c o nf i d e nc e i n te r v a l

I nf l e c ti on p o i n t = 9. 8 m g/k g

E C 10 (p r e d i c te d ) = 1 1. 5 m g/k g

E C 10 (L CL ) = 9 .7 m g/ k g

E C 10 (U C L) = 1 3.6 m g /k g

**Fi gure**  **4**

**. H**  **oc k**  **e y**  **s t**  **i c**  **k r**  **e gr**  **e s**  **s i**  **on of l**  **a bora**  **t ory**  **m a**  **ll a**  **rd duc k**  **l i**  **ng**

**m ort**  **a li**  **t y**  **v e**  **rs us**  **e gg s**  **e l**  **e ni**  **u m** 

**.**T HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 6 c onc entrati on]) s tandard or to s o m e v ersion of a “t ol erab l y toxic ” s tand ard s uch as an EC 1 0 ,

an EC 2 0 , or an EC 0 5 , etc

.

C onc ep tuall y

, a b ench m ark c onc entrati on i s def i n ed as the l oc ati on on the exp o s ureresp on s e c urv e th at i s the thre s hold b etw een ab s e nce an d p re s ence of a g i ven ef f ec t or endp oi nt ( i

. e

. , the thre s hold b etw een an EC 0 0 and an EC 0 1 c onc entrati on [ s ee:

w w w

. ep a. g ov/ec otox/eco s s l /p df /ec o s s l _attac h m ent_3­2

. p df

; p

. A­6] )

. Benc h m ar k

c onc entrati ons are es ti m ated a s the l ow er 95 p erc ent c onfi denc e b oun dar

y o n t he E C 1 0 ( s ee :

M ei s ter and Va n Den Bri nk [ 2000]

, p p

. 114­ 116 i n p arti c ular; and USE PA [ 2000] )

.



### U **nce rt**  **ainty S**  **urroundi ng**  **t he Hoc**  **ke y­**  **S t**  **i ck**  **R egre**  **ss i**  **on I**  **nflect i**  **on P**  **o i**  **nts**

To deter m i ne the i nfl ec ti on p oi nt b etw een the hoc k ey

­ s ti c k “b l ade” and “ha ndle”, or a ny

p arameter i n t he m odel

, i niti al p arameter val ue s a re inp ut to the s of tw are p rogra m SPl u s ®

and an i terati ve tec h niqu e i s us ed to s earc h f or m o re ex ac t p arameter val ue s t hat w i l l

m i nimize th e s u m of s q uared devi ati on s b etw een the ob s erved ef f ec ts data and ef f ec ts

val ues p red i c ted b y the m odel

. Var i ance in the es t i m ate of t he i nfl ec ti on p oi nt val ue i s

af f ec ted b y the s p ac i ng of the m ea s ured X val ue s a s w el l as the s c atter or tre nd i n Y val ue s

i n the vi c i nity of the e s ti m ated i nfl ec ti on p oi nt. I f

, f or ex am p l e, there are f ew m eas ured

di etary s el eni um c onc entrati ons near the p red i c te d i nfl ec ti on p oi nt, th e un c ertai nt

y i n the

l oc ati on of the i nfl ec ti on p oi nt w i l l b e g reater b ec aus e i t w i l l b e di f f i c ult to deter m i ne t he

exact c onc entrati on at w hic h t he i nfl ec ti on p oi nt o c c urs ( i

. e.

, i t c ould b e b etw een tw o of t he

m eas ured val ue s )

. Un c ertai nt y aro un d the p red i c ted Y ( EC) val ue s at t he p red i c ted

i nfl ec ti on p oi nt i s af f ec ted b y t he n um b er of Y val ues an d the s c atter of the Y val ues at that

p arti c ular X v al ue ( w hic h, when c al c ulati ng th e c o nfi denc e i nterval around Y

, i s a s s um ed to

b e es ti m ated w i thou t err or)

. Th us, b oth the s p ac i n g of t he m ea s ured X val ues an d the

vari ance in the res p on s e vari ab l e af f ec ts the un c ert ai nty aro un d t he i nfl ec ti on p oi nt. The

ti g hter s p ac i ng and l es s a m b i g uou s ef f ec ts re s p on s e af ter the i nfl ec ti on p oi nt c au s e s th e

95% C I arou nd the di etary s el e nium

­ b as ed i nfl ec ti on p oi nt ( 3. 0 to 4. 9 m g / k g ) to b e n arr ow er

than t hat f or the eg g s el enium

­ b as ed i nfl ec ti on p oi

nt ( 6. 4 to 14. 9 m g / k g )

.

Ho w ever, al thou g h there i s un c ertai nty s urroundi ng t he i nfl ec ti on p oi n t, u s e of t he b e s t

es ti m ate of the i nfl ec ti on p oi nt resu l t s i n the b es t f i t of the re g res s i on m odel to the data

. I n

F i g ure 4, f or ex a m p l e

, i f th e i nfl ec ti on p oi nt oc c urred at ei ther end of the 95 % C I of e g g

s el enium c onc entrati on ( 6

. 4 to 14

. 9 m g /k g dr

y w t

. ) one c an ea s i l y vi s uali ze that the f i t of the

regres s i on to the data p oi nts abo ve t he i nfl ec ti on p oi nt w ould not p a s s thro ug h th e

m eas ured val ue s i n the s am e w ay

.



### H **orm et**  **i c E**  **f f**  **ec t**  **s of S eleni**  **um**

C ons i der ati on of the hor m eti c ef f ec ts of s el eniu m m ay res ult i n l ow eri ng of thre s hold s ( f or

horm eti c s ubs tance s a nd e ndp oi nt s on e ha s to di s t i ng uis h b etw een val i d c ontrol res p on s es

and hor m eti c def i c i ency res p ons e s b ef ore a val i d b as el i ne to c om p are to xic res p on s es

ag ai ns t c an b e i dentif i ed)

. The horm eti c b i as i n t he data us ed f or th e Ohl endorf ( 2003)

regres s i ons ha s not y et b een f ull y c on s i der ed b y t he Sc i ence P a nel. I f s uch c ons i der ati on

w ere to res ult i n c han g es

, t hos e c han g es c ould onl y b e i n the di rec ti on of a dow nwar d

s hif ti ng of the thre s hold c onfi denc e l i m i ts

. ( F or ex am p l e, p rel i m i nar y un p ubl i s hed a nalys e s

that adj us ted f or horm eti c ef f ec ts i n the m al l ard d ata y i el ded a revi s ed EC 1 0 f or die t ofT HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 7 4. 1 m g /k g

, w i th a 95% C I of 1. 3 to 5. 8 m g / k g

, a nd a revi s ed E C 1 0 f or e g g s of 9. 22 m g / k g

,

w i th a 95 % C I of 4

. 11 to 13

. 07 m g /k g

. )

.



### Ot **her Qual i**  **f i**  **ca t**  **i ons and**  **P oi**  **nts D**  **i sc**  **uss ed** 

The Pa nel al s o di s c u s s ed the f ol l ow i ng addi ti onal qu al i f i c ati ons and p oi nts rel ati ve to

toxic i ty thres hold val ue s :

· Ap p l i c ab i l i ty of l ab orato ry data to f i el d s i tua ti ons i s not c ertai n ( note that f i el d data w ere

retai ned i n c om p i l ati on of e g g

­ s el enium c onc entra ti ons i n Tab l e 2)

, and i t i s i m p orta nt to

c ol l ec t s i te­ s p ec i f i c f i e l d data on s el eniu m c onc en t rati ons i n b i rd eg g s ( e. g

. , c urrent data

g atheri ng ef f ort at the Gre at Sal t Lak e)

.

· Ap p l i c ab i l i ty of m al l ard data to s p ec i es at Gre at S al t Lak e i s un c ertai n, bec aus e rel ati ve

s en s i ti vi ty of al l s p ec i es ne s ti ng there i s not k now n.

· Thres hold val ues discu s s ed are for the hatchab i l i ty end p oi nt ( b a s ed on di et a nd avi a n

eg g ) b ut no n­reprod ucti ve adver s e ef f ec ts end p oi nts (e. g

. , avi an b l ood endp oi nt) al s o

m ay b e i m p ortant

. Ho w ever, i nterp reti ve val ue s f or s el eniu m i n avi an b l ood are n ot

avai l ab l e; al thou g h s el enium c onc entrati ons i n b l ood i ndic ate exp o s ure of t he b i rds, tha t

endp oi nt i s not c on s i der ed u s ef ul f or s etti n g a w at er q uali ty s ta ndard.

· Ph al aropes are s ea s onall y nu m ero u s at the Gre at Sal t Lak e and s ho uld be added to the

l i s t of s p ec i es to b e m onito red b ec au s e t hey repre s ent s p ec i es w i th a f eedi ng rat e th at i s a

l arge p erc enta g e of b ody w ei g ht ( af f ec ti ng e nerg

y c ons i der ati on i n det ermini ng w i l dl i f e

c ri teri on).



## R **e c**  **om m**  **e nd**  **e d**  **N e**  **x t St**  **e ps** 

The i s s ue s s u m m ari zed i n thi s tec h nic al m em ora n dum s ho uld be dis c u s s ed/c ons i der ed

f urth er by the Pan el

, p arti c ularl y to ref i ne the s el e c ti on of thres hold val ue s f or bi rd die t s a nd

eg g s w i th res p ec t to ef f ec ts doc um e nted el s ew her e ( i n f i el d and l ab orato ry s t udies) and

c ons i der i ng t he re s ults b ei ng devel oped throu g h researc h at the Gre at Sal t Lak e

. I n p aral l el

, i t w i l l b e i m p ortant to k now what l evel of p rote c ti venes s t he State and EP A w i l l ap p l y i n the

devel opm ent of th e s i te­ s p ec i f i c s tandard f or s el en i um on the Gre at Sal t La k e ( i

. e

. , EC 2 0 , EC 1 0 , E C 0 5 , etc

. ) s o that the Sc i ence P anel c an mos t ef f ec ti vel y m ak e rec omm e ndatio ns th at

c an b e ap p l i ed tow ard t hat pu rpo s e

.



## R **e f**  **e r**  **e n**  **c e**  **s**

Adam s

, W. J

. , K

. V. Bri x, M

. Edw ards

, L

. M

. Tear

, D

. K

. D e F ore s t

, and A. F ai rb rother. 2003

. An al y s i s of f i el d and l ab orato ry data to der i ve s el e nium to xic i ty thre s hold s f or bi rds.

En vir o n

. To xi col. C he m. 22 : 2

, 020­ 2, 0 29.

Har di ng

, L

. E

. , M

. Gra ham

, and D

. Pato n. 2005

. Acc um ulati on of s el eniu m a nd l ac k of s evere

ef f ec ts on p rod ucti vi ty of Am eri c an di p p er s ( C in cl u s me xic a n u s ) and s p otted s and p i p ers ( Actit is mac u laria )

. Ar ch. E n vir o n

. C o n t a m. To xic o l

. 4 8: 414­ 423

.

He i nz, G

. H.

, a nd D

. J

. Ho f f m an

. 1 996. C o m p ari s on of the ef f ec ts of s el eno­L

­ m ethio nine

,

s el eno­DL­met hioni ne, and s el enized y ea s t on re p rod ucti on of m al l ards

. E n vir o n

. Po ll u t

. 91: 16 9­ 175.T HR ESHO LD VALUES F O R SELENI UM I N G REAT SALT LAKE: S ELECT I O NS BY T HE SCI ENCE PANEL

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) 8 He i nz, G

. H.

, a nd D

. J

. Ho f f m an

. 1 998. M ethy l m erc ury c hlor i de a nd s el enom et hioni ne

i nterac ti ons on health and reproduc ti on i n m al l ards. En v ir o n

. To xic o l

. C hem

. 17: 139­ 145

.

He i nz, G

. H.

, D

. J

. Ho f f m an

, A. J

. K ry nits k y

, and D

. M

. G

. W el l er. 1987

. Rep rod ucti on i n

m al l ards f ed s el eniu m

. En v ir o n

. To xic o l

. C hem

. 6: 4 23­ 433.

He i nz, G

. H.

, D

. J

. Ho f f m an

, and L

. G

. Gol d. 1989

. I m p ai red re p rod ucti on of m al l ards f ed an

organ i c f orm of s el eniu m

. J

. W il dl

. M a n a ge. 53: 418

­ 428.

Lam, J. C

. W

. , S. Tanab e

, M

. H

. W. La m

, P

. K

. S. La m

. 2005. Ris k to b reed i ng s ucc es s of

w aterb i rds b y c onta m i nan t s i n Ho ng K ong : evi denc e f rom trac e el em ent s i n e g g s

. En vir o n

. Po l lu t

. 135 : 481­ 490

.

M ei s ter, R

. , and P

. J

. Van D en Bri nk

. 2000. The anal y s i s of l ab orato ry toxic i ty ex p eri m ent s

. Pag e s 99­ 118 i n T

. S p ark s ( ed. )

, S t a t is t ic s in Ecot o xi colo gy

. J oh

n Wi l ey & Sons

, LT D

, New

Y ork, NY

.

Ohl endorf

, H. M

. 200 3. Ec otoxi c ol og y of s el eniu m

. Pag e s 465­ 500 i n D

. J

. Ho f f m an et al

. , ed s

. Handbo o k o f Ecot o xic o logy

, Sec ond Edi ti on, Lew i s P ubl i s hers

, Boc a Raton

, F L.

Pres s er

, T

. S.

, and S

. N. Luo m a. 2006

. F ore c as ti n g S el enium D i s c harg es to t he Sa n Franci s c o

Bay

­ D el ta E s tuar y : Ec ol og i c al Ef f ec ts of a Propo s e d San L uis D rai n Exten s i on

. Prof e s s i onal

Pap er 1 646. U

. S. Geol og i c al Survey

, Re s ton, VA

.

Skorup a

, J

. P. 1998

. Ris k a s s e s s m e nt f or t he b i ota d atab as e of t he Nati onal I rr i g ati on Water

Quali ty Pro g ram

. U. S

. F i s h and Wi l dl i f e Ser vi c e.

Skorup a

, J

. P. 1999

. B ew are m i s s i n g dat a and u nde rnouri s hed s tati s ti c al m odel s : c om m ent on

F ai rb rother et al. ’s cr i ti c al eval uation. Hu m

. Ecol. R is k Assess

. 5: 1, 25 5­ 1, 262

.

Stanl ey

, J r.

, T. R., J

. W. Sp ann

, G

. J

. Smith

, a nd R. R o s s c oe. 1994

. M ai n and i nterac ti ve ef f ec ts of

ars enic and s el eniu m on m al l ard rep rod ucti on an d duckli ng g row th and s urvival

. A rc h.

En vir o n

. C o n t a m. To xic o l

. 26 : 4 44­ 451.

Stanl ey

, J r.

, T. R., G

. J

. Smith

, D

. J

. Ho f f m a n, G. H

. H ei nz, a nd R. R o s s c oe. 1996

. Ef f ec ts of

b oro n and s el eniu m on m al l ard rep rod ucti on a nd duckli ng g row th a nd s urvival

. En v ir o n

. To xic o l. C hem

. 15: 1, 1 24­ 1, 132

.

U. S. Envir on m ental Protec ti on A g ency ( USEP A). 2 000. Be nchm ar k D os e Tec hn i c al Guid ance

D oc um en t. [ External Review D raf t]

. EP A/ 630/ R­ 00/001. U

. S. Envir on m ental Protec ti on

Ag ency

, Was hing to n, D C

.

Y am a m oto, J

. T

. , and G. M

. Santol o

. 2000

. Bod y c on di ti on ef f ec ts i n Am eri c an kes trel s f ed

s el enom et hioni ne. J

. W il dl

. Di s

. 36 : 646­ 652.**A TT**  **A C**  **HM E**  **NT A** 



# Tabl **e s** AT T ACHMENT A: T ABLES

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) A­1 **TA B**  **LE 1** 

Di et Conc en t r ati on s

**mg/ k**  **g A**  **pp roach**  **or S**  **i t**  **e E**  **f**

**f ec**  **t s**  **S pe**  **ci es**  **R efer**  **en ce(s**  **)**

4. 87

**( C**  **I 3.**  **5 6** 

**­ 5** 

**. 74**  **)** S ynt he si s o f l ab

D at a H at chab i l i t y i n m a l l ards ( 10 % e f

f e ct l e ve l / 95% co nf i de nce

bou nda r i e s) M al l a r d O h l e ndo r f 200 3

4. 4

( C I 3. 8

­ 4

. 8 ) S ynt he si s o f l ab

data E C 10 f o r duck l i ng m o r

t al i t y M al l a r d B i l l A da m s ana l yse s

pre se nt e d i n A t t ach m e n t B

3. 85

­ 7. 7 ( di e t base d

on 10 % m o i s t ure ) Lab R e duce d hatchi ng succe ss i n m al l a r ds ( 3 3% a t 7

. 7 μg / g) ;

r e duce d grow t h an d w e i gh t i n ha t ch l i ngs M al l a r d S t an l e y e t a l

. 199 6

7. 7 ( d i e t ba se d on

10% m o i s t u r e ) Lab R e ducti on i n nu m be r of su r v i v i ng m a l l ar

d du ck l i n gs produce d pe r f e m a l e M al l a r d S t an l e y e t a l

. 199 6

8. 8 4. 4 / 6

. 2 ( d i e t ba se d

on 10 % m o i s t ure ) Lab 8. 8

­ L O A E L, 4

. 4

­ N O A E L

, 6. 2

­ G e o m e t r i c M e an

R e ducti on ( 1 7% ) i n su r v i va l o f m a l l ar d du ck l i n gs; m e an

de cr e ase ( 43%) i n n u m be r of 6

­ day

­ o l d d uck l i ngs M al l a r d H e i nz e t al

. 198 9

6 Lab A dve r se e f

f e ct on bod y co ndi t i on of m al e A m e r i can

ke st r e l s A m e r i ca n K e st r e l s Y a m a m o t o a nd Sa nt o l o

, 2 000

7. 7

­ 8. 8 ( di e t base d

on 10 % m o i s t ure ) Lab D i e t ary t hre shol d o f t e r at oge ni c e f

f e ct s i n m a l l a r ds ;

abo ve upp e r t hre sho l d, r at e o f de f o r m i t y r i se s s harp l y M al l a r d S t an l e y e t a l

. 199 6

7. 7

­ 8. 8 ( di e t base d

on 10 % m o i s t ure ) Lab D i e t ary t hre shol d o f m a l l ar

d du ck l i n g m o r t a l i t y ( pare nt a l

ex posu r e ) M al l a r d S t an l e y e t a l

. 199 6

N o t e : H igh li g h t e d c e ll s a r e t h e t h r e s h o ld v a lu e s f o r b i r d d ie ts i d e n ti fi e d b y

c o n s e n s u s o f th e S c ien c e P a n e l o n N o v e m b e r 3 0

, 2 0 0 6

.AT T ACHMENT A: T ABLES

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) A­2 **TA B**  **LE 2** 

Egg Conce ntra t i on s

**mg/ k**  **g (**  **dry w**  **t**

**. )**  **A pp**  **roach or**  **S i**  **t e**  **E f** 

**f ec**  **t s**  **S pe**  **ci es**  **R efer**  **en ce(s**  **)**

12.5

**( C**  **I 6.**  **4**

**­ 16** 

**. 5**  **)** S ynt he si s o f l ab

data H at chab i l i t y i n m a l l ards ( 10 % e f

f e ct l e ve l / 95% co nf i de nce

bou nda r i e s) M al l a r d O h l e ndo r f 200 3

10 S ynt he si s o f l ab

data N O A E L M al l a r d A da m s e t a l

. 20 03

12 ­ 16 S ynt he si s o f l ab

data E C 10 f o r duck l i ng m o r

t al i t y M al l a r d A da m s e t a l

. 20 03

9 S ynt he si s o f l ab

data I m p ai r e d c l ut ch vi a bi l i t y ( 8. 2 % e f

f e ct s l e ve l ) M al l a r d La m e t a l

. 200 5

8. 2 ( o r 7

. 3 ) ( e gg base d

on 73 % m o i s t ure ) Fi e l d 16% de pre ssi on i n e gg v i ab i l i t y **( 7** 

**. 3**  **i n p**  **ap er**  **)** S pott e d S a ndp i pe r H ardi ng e t al

. 200 5

6 S ynt he si s o f f i e l d

data Th r e shol d ( 3% e f

f e ct l e ve l ) of ha t cha bi l i t y S t i l t s S korupa

, 199 8 ; S korup a, 199 9

5. 1 ( e gg ba se d on

78.4 % m o i s t ure ) Fi e l d 15% de pre ssi on i n e gg v i ab i l i t y A m e r i ca n d i ppe r H ardi ng e t al

. 200 5

N o t e : H igh li g h t e d c e ll s a r e t h e t h r e s h o ld v a lu e s f o r b i r d e g g s i d e n ti f ied b y

c o n s e n s u s o f t h e S c ien c e P a n e l o n N o v e m b e r

3 0

, 2 0 0 6

.**A TT**  **A C**  **HM E**  **NT B**  

# Co **mme nt**  **s on De**  **c e**  **mbe r**  **8**

**, 2**  **0 0**  **6**

**, Draft**  **Tec hnic**  **a l**  **Memor a**  **ndum**ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­1 **A TT**  **A C**  **HM E**  **NT B**  

# Co **mme nt**  **s on De**  **c e**  **mbe r**  **8**

**, 2**  **0 0**  **6**

**, Draft**  **Tec hnic**  **a l**  **Memor a**  **ndum**

**C o**  **m m**  **ents o**  **f B**  **ill A**  **d ams** 

F ol l ow i ng are com m ent s o n Har r y Ohl e ndorf ’s draf t tec hn i c al m e m orandu m to the Gre at

Sal t Lak e Sc i ence Pan el e ntitl ed Threshold Va lu es fo r S e le n iu m i n Gr

ea t S a lt L a k e: S el e ctions by

t he S c ie n ce Pa n el ( D ec em b er 8

, 2006)

.



## Sel **e niu**  **m in**  **B ird D**  **ie t**  **s**

As noted i n the draf t m em ora ndu m

, the m al l ard s tudies us ed i n O hlendor f ( 2003) a s t he

b as i s f or a di etary s el eniu m E C 10 i n b i rds w as b as ed on a “dr

y di et” c ontaini ng ab out

10% m oi s ture

. Althou g h the m oi s t ure c onte nt of t he m al l ard die t w as l ow

, w e rec omm e nd

that stan dard c onven ti on s hou l d b e us ed to p rope rl y adju s t the di etary seleni u m

c onc entrati ons to a dr y w ei g ht b a s i s

. The eq uation f or th e w et w ei g ht­to­ dry w ei g ht

c onvers i on i s i ncl uded i n Attach m ent 1 to thi s m e m orandu m

.

I n Adam s et al

. ( 2003)

, hoc k e y

­ s ti c k regre s s i on w a s u s ed to m odel rel ati ons hips b etw een e g g

s el enium c onc entrati ons and adver s e ef f ec ts i n or der to der i ve to xic i ty thre s hold s

, s uch a s

EC10 val u es

. Ho c k e y

­ s ti c k regre s s i on i s a m odel t hat ha s b een us ed to def i ne a t hres hold

w hen an u nderl y i ng b ac k g ro un d l evel of res p on s e i s un rel ated to the dos e. Thu s

, s uch a

m odel m a y b e rel evant to na turall y oc c urri ng el e m ent s th at are es s ential to b i rds a nd a w i de

vari ety of ot her org anis m s and p arti c ularl y us ef ul f or elemen ts s uch as s el eniu m

, w hic h has

a narrow ran g e b etw een l evel s that are e s s ential a nd l evel s that are to xic to b i rds so that

vari ance aroun d the i nfl ec ti on p oi nt ( thre s hold ) i n the m odel i s s m al l

. A s s hown i n

F i g ure 1 b el ow

, a thre s hold c l earl y ap p ears to e xis t w hen di etary seleni u m i s p l otted vers us

duckli ng m ortal i ty ( w hic h i nco rporated the c um ulati ve ef f ec ts of f erti l i zati on s ucc es s and

hatchab i l i ty )

. The i nfl ec ti on p oi nt oc c urs at a di eta ry seleni um c onc entrati on of 3. 9 m g / k g dry w t. ( p l eas e s ee di s c ussion at end of c om m ent s c onc erni ng u ncer tai nty around the

i nfl ec ti on p oi nt). The p red i c ted E C 10 i s 4

. 4 m g /k g dry w t. (

j us t s l i g htly ab ove the i nfl ec ti on

p oi nt) and the 95% c onfi denc e i nterval aro un d the p red i c ted EC 10 ran g e s f rom 3. 8 to

4. 8 m g /k g dr y w t. The p red i c ted E C 10 of 4. 4 m g / k g dry w t. i s s l i g htly l ow er th an Har ry

Ohl endorf ’s E C 10 of 4. 9 m g / k g dry w t.

, b ut the 95 % c onfi denc e i nterval i s narrow er u s i ng

hoc k ey s ti c k regre s s i on

.



## Sel **e niu**  **m in**  **B ird Egg**  **s**

As noted i n Tab l e 2 of the draf t m em ora ndu m

, the EC10 f or du c k l i n g m ortal i ty

, as reported

i n Ada m s et al

. ( 2003)

, ran g ed f ro m 12­ 16 m g / k g dry w t. The s e E C 10 val ues are b as ed o n a

s y nt hes i s of l ab orato ry s t udies i n w hic h the f i nal e ndp oi nt w a s d uckli ng m ortal i ty ( the s a m e

ef f ec ts data us ed i n t he di etar y E C 10 ev al uation a b ove) and the ran g e of EC10 val ue s ref l ec ts

di f f erent s tati s ti c al ap p roac hes f or an al y zi ng the d ata. An adaptation f rom F i g ure 3 i n

Adam s et al

. ( 2003) i s p rovi ded bel ow

, w i th the 95 % c onfi denc e i nterval i ncl uded

. AsAT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­2 s hown

, th e i nfl ec ti on p oi nt oc c urs at a n e g g s el eni um c onc en trati on of 9

. 8 m g /k g w i th a

p red i c ted EC10 c omp arab l e to that der i ved b y Ha rr y Ohl endorf ( p l eas e s ee di s c u s s i on at

end of c om m ent s c onc erni n g un c ertai nty arou nd t he i nfl ec ti on p oi nt). Ho w ever, the

95% c onfi denc e i nterval u s i ng hoc k e y s ti c k re g res s i on i s m uch narrow er (9. 7 to 1 3. 6 m g / k g dry w t. ) than that der i ved b y Har ry u s i ng l og i s ti c regres s i on ( 6. 4­ 16. 5 m g /k g dr

y w t

. )

. Gi ven that there i s a c l ear e g g s el eniu m t hres hold at w hic h ef f ec ts b e g i n to b e ob s erved

, a

un i m odal m odel

, s uch a s l og i s ti c regre s s i on

, m ay resu l t i n exa g g erated c onfi denc e i nterval s

,

p arti c ularl y i n th e tai l s

.



## U **nc e**  **r tai**  **nty S**  **ur r**  **oundi ng**  **the H**  **o c**  **k e**  **y ­S**  **tic k**  **R e**  **gr e**  **s s**  **ion Infl**  **e c**  **ti on**  **Po ints** 

To deter m i ne the i nfl ec ti on p oi nt b etw een the hoc k ey

­ s ti c k “b l ade” and “ha ndle”, or a ny

p arameter i n t he m odel

, i niti al p arameter val ue s a re inp ut to the s of tw are p rogra m SPl u s ®

and an i terati ve tec h niqu e i s us ed to s earc h f or m o re ex ac t p arameter val ue s t hat w i l l

m i nimize th e s u m of s q uared devi ati on s b etw een the ob s erved ef f ec ts data and ef f ec ts

val ues p red i c ted b y the m odel

. Var i ance in the es t i m ate of t he i nfl ec ti on p oi nt val ue i s

af f ec ted b y the s p ac i ng of the m ea s ured X val ue s a s w el l as the s c atter or tre nd i n Y val ue s

i n the vi c i nity of the e s ti m ated i nfl ec ti on p oi nt. I f

, f or ex am p l e, there are f ew m eas ured

di etary s el eni um c onc entrati ons near the p red i c te d i nfl ec ti on p oi nt, th e un c ertai nt

y i n the

l oc ati on of the i nfl ec ti on p oi nt w i l l b e g reater b ec aus e i t w i l l b e di f f i c ult to deter m i ne t he

exact c onc entrati on at w hic h t he i nfl ec ti on p oi nt o c c urs ( i

. e.

, i t c ould b e b etw een tw o of t he

m eas ured val ue s )

. Un c ertai nt y aro un d the p red i c ted Y ( EC) val ue s at t he p red i c ted

i nfl ec ti on p oi nt i s af f ec ted b y t he n um b er of Y val ues an d the s c atter of the Y val ues at that

p arti c ular X v al ue ( w hic h, when c al c ulati ng th e c o nfi denc e i nterval around Y

, i s a s s um ed to

b e es ti m ated w i thou t err or)

. Th us, b oth the s p ac i n g of t he m ea s ured X val ues an d the

vari ance in the res p on s e vari ab l e af f ec ts the un c ert ai nty aro un d t he i nfl ec ti on p oi nt. The

ti g hter s p ac i ng and l es s a m b i g uou s ef f ec ts re s p on s e af ter the i nfl ec ti on p oi nt c au s e s th e

95% c onfi denc e i nterval around the di etary s el eni um

­ b as ed i nfl ec ti on p oi nt ( 3

. 0 to

4. 9 m g /k g dr y w t. ) to b e narrow er t ha n t hat f or th e eg g s el enium

­ b a s ed i nfl ec ti on p oi nt

( 6. 4 to 14. 9 m g / k g dry w t. )

.

Ho w ever, al thou g h there i s un c ertai nty s urroundi ng t he i nfl ec ti on p oi n t, u s e of t he b e s t

es ti m ate of the i nfl ec ti on p oi nt resu l t s i n the b es t f i t of the re g res s i on m odel to the data

. I n

F i g ure 2, f or ex a m p l e

, i f th e i nfl ec ti on p oi nt oc c urred at t he ei ther end of the 95 % c onfi denc e

i nterval of eg g s el eniu m c onc entrati on ( 6. 4 to 14

. 9 m g / k g dry w t. ) o nce can eas i l y vi s u al i ze

that the f i t of t he re g res s i on to the data p oi nt s ab o ve the i nfl ec ti on p oi nt w o uld n ot p a s s throug h the m eas ured val ue s i n the s am e w ay

.AT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­3 **F i**  **g u**  **re 1** 

**. Ho**  **c k**  **e y**  **s ti**  **c k**  **reg r**  **e s**  **s io**  **n o**  **f la**  **b o**  **ra to**  **ry m**  **a ll**  **a rd**  **d uc**  **k l**  **in g**  **m o**  **rta l**  **it y**  **v e**  **rs u**  **s d**  **ie t**  **a ry** 

**s e**  **l e**  **n iu**  **m**

**.**

**0 %**  **1 0**  **% 2**  **0 %**  **3 0**  **% 4**  **0 %**  **5 0**  **% 6**  **0 %**  **7 0**  **% 8**  **0 %**  **9 0**  **% 1**  **0 0**  **%**

**0**

**. 1**  **1 1**  **0 1**  **0 0** 

**D ie**  **ta ry**  **Se**

**, m**  **g /k**  **g d**  **r y**  **w t.** **D u** **c k** **l in** **g M** **o rta** **l it** **y ,** **%** Em p i ri c a l d a t a

Pr e d i c t e d m o rt a l i t y

9 5 % c o n f i d e n c e i n te rv a l

In f l e c t i o n p o i n t = 3

. 9 m g /k g

EC 1 0 (p re d i c t e d ) = 4

. 4 m g /k g

EC 1 0 (L CL ) = 3

. 8 m g /k g

EC 1 0 (UC L ) = 4 .8 m g / k g

**F i**  **gu re**  **2. H**  **oc key**  **sti ck r**  **e g**  **res si**  **on of**  **l ab**  **or a**  **t ory**  **m a**  **l l**  **ard du**  **ckl i**  **n g m**  **ort a**  **l i**  **t y**  **versus eg**  **g**

**seleni um** 

**.**

**0% 10%**  **20% 30%**  **40% 50%**  **60% 70%**  **80% 90%**  **100%**

**0. 1**  **1 10**  **100**

**E g**  **g Se, mg/**  **kg dry**  **w t** 

**. D** **uc kl** **i ng** **M ort** **al i** **t y,** **%** E m pi r i cal dat a

P r edi ct ed m ort al i t y

95% confide nce inter val

I nf l ect i on poi nt = 9. 8 m g/ k g

E C 10 ( pr ed i ct ed) = 11. 5 m g / k g

E C 10 ( LC L) = 9. 7 m g/ k g

E C 10 ( U C L ) = 13. 6 m g/ k gAT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­4 **AT T**  **ACH MEN**  **T 1** 

**WET WE**  **IGH T** 

**­ T**  **O D**  **RY WEIG**  **H T**  **CO N**  **VERSIO N**  **F O**  **R DIE T**  **ARY SEL**  **EN IU**  **M**

**CO N**  **CE N**  **T RAT**  **ION S**  **IN MALLARD**  **STU D**  **IES**

s o l i d s f io n C o n c e n t ra t W e ig h t W e t io n C o n c e n t ra t D ry W e ig h t

=

Where: f sol i ds = f rac ti on s ol i ds i n di et ( i

. e

. , 0

. 9 i n a di et c ont ai ning

10% m oi s ture)AT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­5 

# C **o m**  **m ents**  **o f**  **A n**  **n e Fairb**  **ro t**  **h er** 

I real i ze t hat I a m l ate ( the l as t? ) on p rovi di ng c om m ent s a nd f eedb ac k o n t he re p ort y ou

p ull ed tog et her f rom our l as t Sal t La k e C i ty m eeti ng o n t hres hold val ue s

. I w as s ort of

hop i ng to s ee the data f ro m Bi l l Ada m s ’ re­ analy s i s of t he do s e­ res p on s e b ef ore repl y i ng

. . . Absen t that

, h ere are m y t hou g hts an d c om m ent s

.

I thin k y ou di d a n a p p ropri ate job p ull i ng to g ethe r w hat w a s di s c u s s ed at the m eeti ng i n regard to di et and eg g thres hold l evel s

. Ho w ever, the m ore I l ook at the d ata i n regard to

s el enium u p tak e and ef f ec ts

, the m ore c onvinc ed do I bec ome th at w e are deali ng w i th a

thres hold p he nom eno n, li k el y b ec aus e of the es s e ntial natu re of the el em e nt. I do b el i eve

that the m ean val ue f or the EC10 that w as s el ec ted f or bo th e ndp oi nt s i s l i k el y to re m ai n

p retty m uch the s am e regardl e s s of w hat dose­re s p ons e m od el i s used

, b ut t he s tandard

err or abo ut the m ean m a y b e di f f erent. Li k el y i t w i l l b e s m al l er when u s i ng a thres hold

m odel s i nce a l og i s ti c m odel te nds to s p read ou t t he C I ’ s a t i ts tai l s

. So

, f or now, I am w i l l i ng

to ap p rove t he doc u m ent as a report of w hat w a s di s c us s ed at the m eeti n g

, b ut not as a f i nal

s ay on w hat w e have ag reed to f or th e EC10 and i t s c onfi denc e i nterval s

.AT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­6 

# C **o m**  **m ents**  **o f**  **T h**  **ere sa**  **Pres se**  **r**

Sug g e s ted addi ti ons to thre s hold di s c ussion w ri te

­ up of 1 2/8/06 :

1) Pag e 1: No te t hat c om p i l ati on of data f or co n s i der ati on w as adapted f rom Pres s er and

Luom a ( 2006)

, t ab l e 15.

2) Pag e 1: No te t hat i n addi ti on to l ab orato ry data

, a c omp i l ati on of f i el d data f or eg g

c onc entrati ons w a s retai ned

.

3) Pag e 1: No te t hat a ny f i nal deter m i na ti on m u s t ta k e i nto ac c oun t s i te­ s p ec i f i c data

c urrently b ei ng g e nerated b y the Gre at Sal t La k e r es earc h ef f ort.

4) Pag e 2 w ord i ng : “T he p anel ag reed b y c on s en s u s t hat the 95 % C I s o n mean s el eni um

c onc entrati ons i n m al l ard die t and eg g s w ould b e reason ab l y p rote c ti ve f or bi rds nes ti n g

at the Gre at Sal t Lak e

, a nd t he ra ng e of val ue s i ncl uded the c onc entrati on s p ropos ed b y

vari ous p anel m em b er s f or co n s i der ati on. Rationa l s u p p orti n g s el ec ti on of the 95 % C I s i s

p rovi ded by t he p revi ou s tec hn i c al m em ora ndu m and thro ug h di s c u s s i on at the p an el

m eeti ng

. ”

a) D i d y o u mean here the 95% C I s on the m ea n E C 10 f or h atc habi l i ty ?

b ) The p hras e “w ould b e rea s onab l y p rote c ti ve f or b i rds ne s ti n g at the Gre at Sal t Lak e”

does no t ade qu atel y c onvey al l p arts of the exte ns i

ve di s c u s s i on that took p l ac e. I di d

not p erc ei ve t hat a co n s en s u s had b een reac hed a s to p rote c ti venes s

, only that a

c ons en s us h ad b een reac hed a s to the i nterp reta ti on of data f rom m al l ard lab

exp eri m ent s

. Theref ore

, I s u g g e s t i nco rporati n g i n to the w ord i ng of a s u m m ar

y

s tatem e nt t he f ol l ow i ng qu al i f i c ati ons and p oi nt s t hat w ere di s c ussed a t the m eeti ng :

1) Ap p l i c ab i l i ty of l ab data to f i el d s i tuation s ( note re tention of c om p i l ati on of f i el d

data i n tab l e 2 and c urrent data g at heri ng ef f ort at the Gre at Sal t La k e; p oi nt s

2 and 3 l i s ted ab ove)

2) Ap p l i c ab i l i ty of m al l ard data to s p ec i es at Gre at S al t Lak e ( s en s i ti vi ty i s s ue)

3) Ap p l i c ab i l i ty of hatchab i l i ty endp oi n t ( di et a nd av i an eg g ) and no n­reprod ucti ve

adver s e ef f ec ts end p oi nts (e. g

. , avi an b l ood end p o i nt)

4) Level of p rote c ti on a nd p rec autionary reg ulati on a s e xem p l i f i ed b y b enchm ar k

c onc entrati on regu l ati on

. S p ec i f i c al l y add ex c erpt f rom p a g e 8 of 11 /28/06

m em o as c l ari f i c ati on of 95% C I : “ C onc ep t uall y

, a b enchm ark c onc entrati on i s

def i ned as the l oc ati on on t he e xp o s ure­r es p on s e c urve that i s the thre s hold

b etw een ab s ence and p rese nce of a g i ve n ef f ec t or endp oi nt, i. e

. , the thre s hold

b etw een an E C 00 and an EC01 c onc entrati on ( s ee:

w w w

. ep a. g ov/ec otox/eco s s l /p df /ec o s s l _attac h m ent_3­2

. p df

; p

. A­6)

... . . Benc hm ark c onc entrati on s are es ti m ated a s the l ow er 95% c onfi denc e b oun dary

on the EC1 0 ( s ee : M ei s ter, R

. , and P. J

. Va n Den Bri nk

. 2000

. T he a nalys i s of

l ab orato ry toxic i ty ex p eri m ent s

. Pa g es 99­ 118 i n T

. Spark s ( ed. )

, Stati s ti c s i n

Ec otoxi c ol og y

. J ohn Wi l ey & Sons

, LT D

, New Y or k

, NY: [ p p 114­ 116 i n

p arti c ular] ; and s ee : USEPA

. 2000. Benc h m ark D o s e Tec hn i c al Guid anceAT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­7 D oc um en t. [ External Review D raf t]

. EP A/ 630/ R­ 00/001. U

. S. Envir on m ental

Protec ti on Ag e ncy, Wa s hin g ton

, D C )

. ”

5) Addi ti on of p halar ope to l i s t of s p ec i es to b e m oni tore d to re p resen t s p ec i es w i th

a f eedi ng rate t hat i s a l arge perc entag e of b ody w ei g ht ( ener g y c ons i der ati on i n

deter m i ning w i l dl i f e c ri ter i on).

6) Potent i al l ow eri ng of t hres hold s t hrou g h c on s i der ati on of hor m es i s data ( f or

horm eti c s ubs tance s a nd e ndp oi nt s on e ha s to di s t i ng uis h b etw een val i d c ontrol

res p on s es and hor m eti c def i c i ency res p ons es b ef ore a val i d b a s el i ne to c o m p are

toxic resp o ns e s a g ai n s t c an b e i dentif i ed)

.

5) Refere nces: A dd Pre s s er and Luo m a, 2006

.

6) Tab l e 1: ”Bi l l Adam s s u g g e s ti on” need s to b e doc u m ented as how his entry di f f ers f rom

entry #1 i n tab l e 1.AT T ACHMENT B: CO MM ENT S O N DECEM BER 8, 20 06

, DR AF T T ECHN I CAL M EM O RAND U M

ES022 00 70 0 4SAC/341 05 5/07 03 8 00 0 1 (DO CU ME NT 1) B­8 

# C **o m**  **m ents**  **o f**  **J o**  **e S koru**  **p a** 

I n Tab l e 1 I don ’t b el i eve the s c i ence p anel w anted the val ue of 4. 87 to b e p re s ented i n b ol d

ty p e

, onl y t he c onfi denc e l i m i ts ( f or co m p ari s on s ee Tab l e 2 w here I thin

k y ou have i t t he

w ay the s c i ence p anel i nten ded)

.

Adj u s ti ng f or 10 % m oi s ture w ould re s ult i n an 11 % i ncr eas e i n the di etar

y val u es

, not an

up w ard ad ju s tm ent of 10 % as s ta ted.

I di dn’ t f eel l i k e y our draf t w ri te­ up adequ atel y c o nvey ed our ( s c i

. p anel’ s ) di s c u s s i on

c onc erni ng the f ac t tha t, ulti m atel y

, a c hoic e of n u m b ers f rom w i thin t he c on s en s u s

c onfi denc e l i m i ts i s not a s c i entif i c dec i s i on. That c onfi denc e rang e i s as f ar a s s c i ence can

b ri ng u s

. . . c hoos i n g a s p ec i f i c nu m b er or nu m b ers f rom w i thin tho s e c onfi denc e rang e s are

p hil os oph i c al /legal dec i s i on s t hat de p end on how p rec autionar

y t he State of U tah w a nts to

b e ( a m atter of p hil os op hy ) a nd o n how m uch p ot ential f or legal l i ab i l i ty the State i s

c omfor tab l e w i th exp o s i ng i ts el f to

. The k e y dec i s i on the State m u s t m a k e i s w het her t hey

w ant to re g ulate to a “NE C ” ( no ef f ec ts c onc entrat i on.

. . w hic h i s not t he s am e a s a NO EC)

s tandard or to s o m e ver s i on of a “tol erab l y toxic ” s tandard s uch a s a n E C

­ 10, or E C

­ 20, or

EC­05 etc

.

F i nall y

, I thin k on the s c i entif i c s i de of thing s w e w ould b e remis s i n our dut

y a s exp ert s

not to i ncl ude s o m e di s c ussion i ndic ati ng that the i s s ue of hor m eti c b i as i n the data u s ed f or

the Ohl endorf ( 200 3) regre s s i on s ha s not y et b een f ull y c ons i der ed b y the s c i ence p anel ( at

Bi l l Adam s reque s t to def er it s o that he c ould p re vi ew Bec k on’ s SET A C p rese ntation b ef ore

I p resen ted a ny of i t to the p a nel.

. . al thou g h i t s ee m ed to b e ac c ep tab l e to everyon e to s ee

K enn ec ott’s U

. of Wy o m i ng p re s entation w i thou t any o p p ort un i ty f or an

y one other than

Bi l l A. to p revi ew i t.

. . s eem s l i k e a do ubl e s ta ndar d to m e)

, and that i f s uch c on s i der ati on

w ere to res ult i n c han g es

, t hos e c han g es c ould onl y b e i n the di rec ti on of a dow nwar d

s hif ti ng of the thre s hold c onfi denc e l i m i ts

.

F or ex a m p l e

, re m em b er t hat the analy s i s that Brad Sam p l e re­ ran to adj us t f or h or m eti c

ef f ec ts i n the m al l ard data y i el ded a revi s ed E C

­ 10 f or die t of 3

. 7 p p m w w [ 4. 1 p p m dw ]

w i th a 95 % c onfi denc e i nterval of 1

. 15

­ 5. 18 p p m w w [ 1. 3

­ 5

. 8 p p m dw ] and a revi s ed

EC­10 f or e g g s of 9. 22 p p m dw w i th a 95 % c onfi denc e i nterval of 4

. 11

­ 13

. 07 p p m dw

.