# Tier I method fo r es tima ting ex posur e of honey bees to p es ticides **1** U.S. Environmental Pr otection Agency



## Kr is Garber

, M.S. En vir onmental F ate and E ffe cts Division Of fice of P es ticide Pr ogr ams

# Outline

• 

## Over view of Tier I e xposur e assessmen t

• 

## Fo od Consumption

• 

### Wha t do honey bees eat?

• 

### Pr oposed f ood consumption r ates fo r lar va l U.S. Environmental Pr otection Agency **2**

• 

### Pr oposed f ood consumption r ates fo r lar va l and adult w ork er s

• 

### Discussion of conserv at iv eness of pr oposed consumption rate s



### • 

## Es timating Exposur es f or Tier I assessmen t

• 

### Foliar Spr ay Applications

• 

### Seed T re at ments

• 

### Soil Applications

# Ov er view of Tier I e xposur e assessmen t U.S. Environmental Pr otection Agency **3**



# Ov er view of Tier I e xposur e assessmen t

# Purpose of Tier I Exposur e Assessmen t

• 

## The goal is to gener ate “r easonably conser vat iv e” es timates of pes ticide ex posur es t o bees

• 

## Intended to distinguish between:

• 

### Pe st icides tha t do not pose a risk to bees and U.S. Environmental Pr otection Agency **4**

• 

### Pe st icides tha t do not pose a risk to bees and

• 

### those that ma y need additional inf ormation



### • 

## Ty pe I and II Err or s

• 

### Tier I assessment should not conclude that ther e is no eff ect when ther e actually is (T

ype II)

• 

### It is mor e acceptable at the Tier I lev el to conclude tha t ther e is a pot ential eff ect when ther e is none (T ype I)1. Details of the pr oduct and its use pat te rn
2b. Is e xposure of bee brood a concern? Ye s No

Contact Exposur e Or al Exposur e Or al Exposur e No Tier 1 br ood assessment Presumption of minimal risk 

### Tier I e xposur e assessment component of decision tr ee f or fo liar spr ay applications.

2a. Is e xposure of adult bees a concern? U.S. Environmental Pr otection Agency **5**

3a. Calculat e Tier 1 scr eening

- level EEC f or **adult contact exposure**  3b. Calculat e Tier 1 scr eening

level EEC f or **adult or**  **al exposur**  **e** via pollen and nect ar 3c. Calculate Tier 1 scr eening

- level EEC f or **larv al**  **or al exposur**  **e** via br ood f ood
4a. Calculat e Tier 1 scr eening

- level RQs f or adult contact exposur e **(RQ = EE C/**  **adult acut e**  **contact LD**  **50 )**  4b. Calculat e Tier 1 scr eening

level RQs f or adult or al exposur e **(RQ = EE C/**  **adult acut e**  **or al LD**  **50**

**& RQ = EEC/**  **adult chr onic**  **NO AE**  **C** )* 4c. Calculate Tier 1

scr eening

- level RQs f or larval or al exposur e **(RQ = EE C/larval acute LD**  **50**

**& RQ= EEC/larval chr**  **onic NO**  **AE C)** *1. Details of the pr oduct and its use pat te rn
2b. Is e xposure of bee brood a concern? Ye s No

Or al Exposur e Or al Exposur e No Tier 1 br ood assessment Presumption of minimal risk 

### Tier I e xposur e assessment component of decision tr ee f or seed and soil tr eatments.

2a. Is e xposure of adult bees a concern? U.S. Environmental Pr otection Agency **6**

3a. Calculat e Tier 1 scr eening

level EEC f or **adult or**  **al exposur**  **e** via pollen and nect ar 3b. Calculat e Tier 1 scr eening

- level EEC f or **larv al**  **or al exposur**  **e** via br ood f ood
4a. Calculat e Tier 1 scr eening

level RQs f or adult or al exposur e **(RQ = EE C/**  **adult acut e**  **or al LD**  **50**

**& RQ = EEC/**  **adult chr onic**  **NO AE**  **C** )* 4b. Calculat e Tier 1

scr eening

- level RQs f or larval or al exposur e **(RQ = EE C/larval acute LD**  **50**

**& RQ= EEC/larval chr**  **onic NO**  **AE C)** *

# Fo od co nsumption of honey bees U.S. Environmental Pr otection Agency **7**



# Fo od co nsumption of honey bees

### • 

## What do honey bees eat?

• 

### Po llen

• 

### Bee br ead

• 

### Nect ar

• 

### Honey U.S. Environmental Pr otection Agency **8** 

# Honey bee diet

• 

### Honey

• 

### Jelly

• Ro ya l Jelly

• Br ood Food



### • 

## Fo od consumption v aries

• 

### By c as te

• 

### By a ge

# Pr oposed fo od consumption ra te s fo r Tier I e xposur e assessmen t

• 

## Adult honey bees = 292 mg f ood/da y

• 

### Based on nectar f or aging wo rk er

• 

### Re pr esents consumption of nectar

• 

### Po llen consumption is insignificant r elative to nectar U.S. Environmental Pr otection Agency **9**

• 

### Po llen consumption is insignificant r elative to nectar



### • 

## Lar va e = 120 mg f ood/da y

• 

### Based on 5 da y old w ork er larv ae

• 

### Re pr esents consumption of honey (con ve rted to nectar equiv alent) and pollen

### • 

### Pe sticide does not dissipat e while st or ed in the hive

• 

### Pe sticide concentr ations in pollen and bee br ead ar e equiv alent

• 

### Pe sticide concentr ations in nectar can be used to represent concentr ations in honey

• 

### Honey c onsumption r ate ca n be c on verted to a nect ar equiv alen t U.S. Environmental Pr otection Agency **10** 

# Assumptions fo r Tier I Exposur e Assessmen t (r ela te d to F ood Consumption)

• 

### Honey c onsumption r ate ca n be c on verted to a nect ar equiv alen t basis

• 

### Using sug ar consumption r ates and sug ar contents of honey and nectar

• 

### Pe sticide doses will be eqiv alent

• 

### Pe sticide doses received fr om pollen and nect ar are pr ot ective of doses fr om jelly

• 

### Ava ilable data indicate that pesticides are ≥100x greater in f ood of nur se bees compared to r oyal jelly

• 

### Pe sticide c oncen tr ation in f oliag e = c onc. in nect ar = c onc. in pollen

# Pr oposed fo od consumption ra te : Adult Wo rk er Bees

• 

## Fo od Consumption r ate s f or adult work er bees

• 

### Nect ar: R ortais et al. (2005)

• 

### Po llen: Cr ailsheim et al (1992)

• 

### Nect ar f or ager bees ha ve highes t f ood consumption r ates U.S. Environmental Pr otection Agency **11**



### Consumption **rate (mg**  **/da y)**  **Adult work**  **er task Age**  **(d) Consumption**  **rate (mg**  **/da y)**  **Po llen**  **Nectar To**  **tal fo**  **od** Cell cleaning and capping 0

- 10 2.2

- 8.2 60 62

- 68 Br ood and queen attending 6

- 17 1.7

- 9.5 113

- 167 115

- 177 Comb building , cleaning and fo od handling 11

- 18 1.7 60 62 For ager (pollen) >18 0.041 35

- 52 35

- 52 For ager (nect ar) >18 0.041 107

- 428 107

- 428

# Pr oposed fo od consumption ra te : Adult Wo rk er Bees = 292 mg /da y

• 

## Pr oposed v alue is es timated using modification to Ro rt ais et al. ’s method

• 

### Monte Carlo Simulation of 5 v ariables

• Sug ar required fo r flying U.S. Environmental Pr otection Agency **12**

50% 60% 70% 80% 90% 100%Percentile

• Sug ar required fo r flying

• Number of f or aging trips made in a da y

• Dur ation of f or aging trip

• Fr action of time spent flying during trip

• Amount of sug ar pr esent in nect ar

• 

### Analysis also included sug ar requirements while r es ting

• 

### Pr oposed v alue is median of 10,000 simulated bees 0% 10% 20% 30% 40% 50%

0 200 400 600 800 Nectar consumption (mg/day)PercentileU.S. Environmental Pr otection Agency **13** 

### Nectar and pollen consumption **rate s of adult work**  **er bees by task and dr ones.** 

150 200 250 300 Po llen

Nectar**F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**

0 50 100 150

Wo rk er (cell cleaning and capping) Wo rk er (brood

and queen tending, nurse bees) Wo rk er (comb

building, cleaning and fo od handling) Wo rk er

(foraging fo r pollen) Wo rk er

(foraging fo r nectar) Wo rk er

(maintenance of hive in winter) Drone

**Caste (task)** **F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**150 200 250 300 Po llen

Honey**F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)** U.S. Environmental Pr otection Agency **14** 

### Hone **y and pollen consumption rate**  **s of adult work er bees by task and dr**  **ones.**

0 50 100 150

Wo rk er (cell cleaning and capping) Wo rk er (brood

and queen tending, nurse bees) Wo rk er (comb

building, cleaning and fo od handling) Wo rk er

(foraging fo r pollen) Wo rk er

(foraging fo r nectar) Wo rk er

(maintenance of hive in winter) Drone

**Caste (task)** **F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**

# Comparison of pr oposed fo od consumption ra te s (mg /da y) to non -

Apis bees: Adults

**Species Nectar**  **Po llen**  **To tal**  **fo od**  Honey bee wo rk er ( Apis mellif

era ) 292 0.04 292 Bumblebee U.S. Environmental Pr otection Agency **15**



### (Bombus spp . ) 183

- 372 27

- 30 210

- 402 Eur opean mason bee (Osmia cornuta) 45

- 193 na 45

- 193 Alf alf a leaf

- cut ting bee ( Megachile rotundat a ) 110

- 165 na 110

- 165

# Pr oposed fo od consumption ra te : Lar va l Wo rk er Bees

• 

## It is assumed that lar va e gr ow exponentially and that their daily fo od consumption r ate doubles ev ery da y

• 

### Consume 120 mg total f ood during da ys 4 and 5

• 5.4 mg pollen

• 115 mg honey (dilut ed to 45% sug ar; R ort ais et al. 2005) U.S. Environmental Pr otection Agency **16**



### Da **y of lif e**  **stage Daily f**  **ood consumption rate**  **(mg /da**  **y)**

**Br ood**  **fo od /**  **royal jelly Hone**  **y Po**  **llen To**  **tal food** 1 3.8 none none 3.8 2 7.5 none none 7.5 3 15 none none 15 4 none 37 2.7 40 5 none 77 2.7 80

# Pr oposed fo od consumption ra te : Lar va l Wo rk er Bees

• 

## Pr oposed v alue of 120 mg /da y is based on 5 th 

## da y of lif e s ta ge

• 

### Highes t f ood consumption v alue compar ed to other da ys of lar va l lif e sta ge

• 

### Consumption of 2.7 mg pollen

• 

### Honey consumption r ate is con ve rted to nectar equiv alent r ate U.S. Environmental Pr otection Agency **17**



### (117 mg /da y)150 200 250 300 Ro ya l jelly/br ood f ood Po llen Honey**F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)** 

### Hone **y, p**  **ollen and br ood**  **fo od or r**  **oy al jelly consumption**  **rate s of larv**  **ae of diff**  **er ent castes and ages.**  U.S. Environmental Pr otection Agency **18**

0 50 100 150

Wo rk er (1) Wo rk er (2) Wo rk er (3) Wo rk er (4) Wo rk er (5) Dr one (5) Dr one (6) Queen (1) Queen (2) Queen (3) Queen (4) Queen (5) **Caste (day of**  **life stage )** **F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**150 200 250 300 Ro ya l jelly/br ood f ood Po llen Honey**F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)** U.S. Environmental Pr otection Agency **19** 

### Hone **y, p**  **ollen and br ood**  **fo od or r**  **oy al jelly consumption**  **rate s of larv**  **ae of diff**  **er ent castes and ages.** 

0 50 100 150

Wo rk er (1) Wo rk er (2) Wo rk er (3) Wo rk er (4) Wo rk er (5) Dr one (5) Dr one (6) Queen (1) Queen (2) Queen (3) Queen (4) Queen (5) **Caste (day of**  **life stage )** **F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**150 200 250 300 Ro ya l jelly/br ood f ood Po llen Honey**F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)** U.S. Environmental Pr otection Agency **20** 

### Hone **y, p**  **ollen and br ood**  **fo od or r**  **oy al jelly consumption**  **rate s of larv**  **ae of diff**  **er ent castes and ages.** 

0 50 100 150

Wo rk er (1) Wo rk er (2) Wo rk er (3) Wo rk er (4) Wo rk er (5) Dr one (5) Dr one (6) Queen (1) Queen (2) Queen (3) Queen (4) Queen (5) **Caste (day of**  **life stage )** **F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**U.S. Environmental Pr otection Agency **21**

150 200 250 300 Royal jelly/brood food

Po llen Nectar**F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)** 

### Nectar **, pollen and br ood**  **fo od or r**  **oy al jelly consumption**  **rate s of larv**  **ae of diff**  **er ent castes and ages.** 

0 50 100 150

Wo rk er (1) Wo rk er (2) Wo rk er (3) Wo rk er (4) Wo rk er (5) Drone (5) Drone (6) Queen (1) Queen (2) Queen (3) Queen (4) Queen (5) **Caste (day of**  **life stage )** **F o** **o d** **c o** **n s** **u m** **p t** **i o** **n (** **m g** **/ d** **a y** **)**8

10 12 14 Royal jelly/brood food

Po llen Nectar**g a** **. i** **. /** **b e** **e )**  U.S. Environmental Pr otection Agency **22** 

### Pe **sticide doses**  **re ceiv**  **ed by larv ae of diff**  **er ent castes and ages through**  **consumption of pollen**  **and nectar containing 100 μ**  **g a.i./kg and r**  **oy al jelly containing 1**  **μ g a.i./kg.** 

0 2 4 6 8

Wo rk er (1) Wo rk er (2) Wo rk er (3) Wo rk er (4) Wo rk er (5) Drone (5) Drone (6) Queen (1) Queen (2) Queen (3) Queen (4) Queen (5) **Caste (day of**  **life stage )** **P e** **s t** **i c** **i d** **e d** **o s** **e (** **μ g** **a .** **i .** **/ b** **e e** **)**

# Comparison of pr oposed fo od consumption ra te s (mg /da y) to non -

Apis bees: Lar va e U.S. Environmental Pr otection Agency **23**



### Species **Male/ f emale**  **Nectar Po**  **llen To**  **tal fo**  **od** Honey bee ( Apis mellif

era) Female 117 2.7 120 Bumblebee (Bombus spp . ) unknown 60 22

- 23 82

- 83 Eur opean mason bee (Osmia cornuta) Female 1.8 16.3 18 Male 1.1 9.5 11 Alf alf a leaf

- cut ting bee ( Megachile rotundat a ) Female 6.2 3.1 9.3 Male 5.2 2.6 7.8

# Summary of F ood Consumption Analy sis

• 

### Assume that pesticide doses received thr ough c onsumption of pollen and nect ar c an be used t o c onser vatively represent other types of fo od

• 

### Pr oposed f ood c onsumption r ates

• 

### Adults = 292 mg /da y (nect ar f or ager) Larv ae = 120 mg /da y (5 da y old) U.S. Environmental Pr otection Agency **24**

• 

### Larv ae = 120 mg /da y (5 da y old)

• 

### Appear to be pr otectiv e fo r other honey bees and some non

- Apis bees

• 

### In te rested in SAP comments on pr oposed f ood c onsumption r ates, related assumptions, streng ths and limit ations

• 

### Char ge question 5

• 

### In te rested in SAP comments on r elative pr ot ectiveness of pr oposed fo od c onsumption r ates in representing e xposures t o non - Apis bees

• 

### Char ge question 3

# Tier I me thods fo r es tima ting pes ticide concen tr ati ons on bees and in pollen and nect ar U.S. Environmental Pr otection Agency **25**



# concen tr ati ons on bees and in pollen and nect ar

# Es tima ting pes ticide ex posur es fo r Tier I assessmen t

• 

## Fo liar applications

• 

### Contact EEC

- Ko ch and We isser 1997

• 

### Dietary EEC

- T

- REX tall gr ass upper bound



### • 

## Seed tr ea tmen ts Dietary EEC

- EPPO def ault v alue of 1 mg a.i./kg U.S. Environmental Pr otection Agency **26**

• 

### Dietary EEC

- EPPO def ault v alue of 1 mg a.i./kg



### • 

## Soil tr ea tmen ts

• 

### Dietary EEC

- Modified Brig gs’ Model



### • 

## All dietary EECs con ve rt ed t o a dose using pr oposed f ood consumption r ate s f or adult (292 mg /da y) and lar va l (120 mg /da y) work er s

# Iden tific at ion and Ev alua tion of Methods

• 

## Methods consider ed

• 

### Man y ar e curr ently used f or regulatory purposes

• 

### Other methods a va ilable in the open liter at ur e



### • 

## Eva luation of Methods U.S. Environmental Pr otection Agency **27**



### • 

## Eva luation of Methods

• 

### Compar ed to empirical data fr om scientific liter at ur e and unpublished re gis tr ant studies

• 

### Amount of data a va ilable to ev aluate each method v aried **Applica tion**  **type (r**  **out e)**  **Method Number**  **of studies** Foliar spr ay (contact) Ko ch and We isser 2 Foliar spr ay (diet) T

- REX (t all gr ass) 11 Seed tr eatment (diet) EPPO (1 mg /kg) 12 Soil tr eatment (diet) Brig gs’ Model 6

### • 

## Description of Pr oposed Method

• 

### Contact Dose = 2.7 μ g a.i./bee * Application r ate (in lb a.i./ A)

• 

### Fr om K och and We isser (1997) U.S. Environmental Pr otection Agency **28** 

# Es tima ting Con ta ct Exposur es fo r Fo liar Spr ay

A pplic at ions

• 

### Fr om K och and We isser (1997)

• 

### Based on maximum concentr at ion of chemical tr acer measur ed on bees fo ra ging on treated ar eas

• 5 trials on Phacelia fields (tot al number of bees analyz ed = 1724)

• 9 trials on apple or char ds (tot al number of bees analyz ed = 4316)U.S. Environmental Pr otection Agency **29** 

# Es tima ting Con ta ct Exposur es fo r Fo liar Spr ay

A pplic at ions

70 80 90 100 Tr ial 1

Tr ial 2**o f** **b e** **e s** **i n** **t r** **i a** **l** 

### Fr **equency distribution**  **of measur ed tr**  **acer on individual bees during 5 trials with**  **Phacelia fields.** 

43% of bees

0 10 20 30 40 50 60 70

<=0.26 >0.26 to

<=0.53 >0.53 to <=0.79 >0.79 to

<=1.1 >1.1 to <=1.3 >1.3 to <=1.6 >1.6 to <=1.8 >1.8 to <=2.1 >2.1 to <=2.4 >2.4 Tr ial 3

Tr ial 4

Tr ial 5**P e** **r c** **e n** **t o** **f b** **e e** **s i** **n t** **r i** **a l** 

**Mass of tracer measured on individual bees**  **( μ**  **g a.i.**  **/bee per 1 lb/A)** 70

80 90 100 Tr ial 1 Tr ial 2 Tr ial 3**o f** **b e** **e s** **i n** **t r** **i a** **l** U.S. Environmental Pr otection Agency **30** 

# Es tima ting Con ta ct Exposur es fo r Fo liar Spr ay

A pplic at ions **Fr equency**  **distribution of measur**  **ed tr acer on individual**  **bees during 9 trials with apple or**  **char ds.** 

71% of bees

0 10 20 30 40 50 60 70

<=0.26 >0.26 to

<=0.53 >0.53 to <=0.79 >0.79 to

<=1.1 >1.1 to <=1.3 >1.3 to <=1.6 >1.6 to <=1.8 >1.8 to <=2.1 >2.1 to <=2.4 >2.4 Tr ial 4

Tr ial 5 Tr ial 6 Tr ial 7 Tr ial 8 Tr ial 9**P e** **r c** **e n** **t o** **f b** **e e** **s i** **n t** **r i** **a l** 

**Mass of tracer measured on individual bees**  **( μ**  **g a.i./bee per 1 lb/A)** 

### • 

## Discussion of R elev ance of T

- REX arthr opod r esidue v alue

• 

### Contact Dose = 12 μ g a.i./bee * Application r ate (in lb a.i./ A)

• Va lue r epr esents 95 th per centile re sidue value (94 mg a.i./kg) convert ed to a dose using weight of a bee (0.128 g) U.S. Environmental Pr otection Agency **31** 

# Es tima ting Con ta ct Exposur es fo r Fo liar Spr ay

A pplic at ions

• 

### Based on analysis of pes ticide r esidues on crick ets, gr asshopper s, beetles, etc. located on treated field at the time of the application

• Limit ation: dat a set does not include re sidue dat a f or honey bees

### • 

## Method E va luation

• 

### No upper bound re sidues a va ilable to ev aluate pr oposed v alue

• 

### Mean Ko ch and We isser (1997) da ta and T

- REX arthr opod residue v alues ar e consis tent with means of empirical data fr om 2 other s tudies U.S. Environmental Pr otection Agency **32** 

# Es tima ting Con ta ct Exposur es fo r Fo liar Spr ay

A pplic at ions

8 9**a .** **i .** **/ b** **e e** **p e** **r 1** **l b** **a .** **i .** **/ A** **)**

0 1 2 3 4 5 6 7 8

T

- REX (arthr opod) Koch and

We isser 1997 (Phacelia) Koch and

We isser 1997 (apple) Delabie et al.

1985 Hann y and

Harvey 1982 Hann y and

Harvey 1982
**Source M** **e a** **n c** **o n** **t a** **c t** **d o** **s e** **( μ** **g a** **. i** **. /** **b e** **e p** **e r** **1 l** **b a** **. i** **. /** **A )** 

### • 

## Assumptions and Uncertainties

• 

### Limited number of s tudies a va ilable f or evaluation of method

• 

### Based on only tw o cr ops

• 

### Based on one s tudy site U.S. Environmental Pr otection Agency **33** 

# Es tima ting Con ta ct Exposur es fo r Fo liar Spr ay

A pplic at ions

• 

## Str eng ths of pr oposed method

• 

### Ko ch and We isser (1997) maximum v alue appear s t o be conserv at iv e

• 

### Ro bus t st udy design

• Maximum value is based on measur ements of >6000 bees

• Tr acer did not impact study r esults

• 

### Consis tent with other methods that are empirically based

• T

- REX arthr opod r esidue v alue (f actor of 5 diff er ent)

• At kins et al. 1981

### • 

## Description of Pr oposed Method

• 

### Use T

- REX upper bound re sidue v alue on f oliage as a surr og ate fo r pollen and nectar

• 

### Suf ficient data are not a va ilable to deriv e nect ar or pollen specific r esidue va lues U.S. Environmental Pr otection Agency **34** 

# Es tima ting Die ta ry Exposur es fo r Fo liar Spr ay

A pplic at ions

**Plant Description**  **Concentr ation (mg a.i./kg per 1 lb a.i./**  **A) Upper** 
**- bound**  **Mean** Short gr ass 240 85 Br oadleaf plants 135 45 Ta ll gr ass 110 36 Fruit, pods and seeds 15 7• 

### Method Eva luation: mean empirical data f or nectar (n = 10)

• Mean residues fo r short gr ass, broad leaf plants and tall gr ass are all higher than mean empirical data

• 4 empirical va lues exc eed the mean residue fo r fruit, pods and seeds

• Maximum residues only available fo r some studies (0.17

- 2.2 mg a.i./kg per 1 lb a.i./ A) U.S. Environmental Pr otection Agency **35** 

# Es tima ting Die ta ry Exposur es fo r Fo liar Spr ay

A pplic at ions

90 100**A )**  Short grass

0 10 20 30 40 50 60 70 80 90

**chemical m** **e a** **n c** **o n** **c e** **n t** **r a** **t i** **o n** **( m** **g a** **. i** **. /** **k g** **p e** **r 1** **l b** **a .** **i .** **/ A** **)** Short grass

Broadleaf Tall grass

Fruit, etc.• 

### Method Eva luation: mean empirical data f or pollen (n = 9)

• Mean residue fo r short gr ass is higher than mean empirical data

• Mean residues fo r broad leaf plants and tall gr ass higher than all but one residue va lue

• 5 empirical va lues exc eed the mean residue fo r fruit, pods and seeds U.S. Environmental Pr otection Agency **36** 

# Es tima ting Die ta ry Exposur es fo r Fo liar Spr ay

A pplic at ions

80 90 100**A )**  Short grass

0 10 20 30 40 50 60 70 80

**chemical m** **e a** **n c** **o n** **c e** **n t** **r a** **t i** **o n** **( m** **g a** **. i** **. /** **k g** **p e** **r 1** **l b** **a .** **i .** **/ A** **)** Short grass

Broadleaf Tall grass

Fruit, etc.

### • 

### Method E va luation: maximum empiric al data f or pollen (n = 14)

• 

### Upper bound r esidues f or short gr ass, br oadleaf plants and tall gr ass ar e higher than empirical data

• 

### 7 empirical v alues ex ceed the mean r esidue f or fruit, pods and seeds U.S. Environmental Pr otection Agency **37** 

# Es tima ting Die ta ry Exposur es fo r Fo liar Spr ay

A pplic at ions

200 250**M a** **x c** **o n** **c e** **n t** **r a** **t i** **o n** **a .** **i .** **/ k** **g p** **e r** **1 l** **b a** **. i** **. /** **A )**  Short grass

0 50 100 150 200

**chemical M** **a x** **c o** **n c** **e n** **t r** **a t** **i o** **n (** **m g** **a .** **i .** **/ k** **g p** **e r** **1 l** **b a** **. i** **. /** 

Broadleaf Tall grass

Fruit, etc.

### • 

## Summary of E va luation and Pr oposed Method

• 

### Short gr ass, br oad leaf plant and tall gr ass r esidues ar e consis tently conserv at iv e relative to mean and maximum residue data f or pollen and nect ar Only one value ex ceeds t all gr ass and br oad leaf plant r esidues U.S. Environmental Pr otection Agency **38** 

# Es tima ting Die ta ry Exposur es fo r Fo liar Spr ay

A pplic at ions

• Only one value ex ceeds t all gr ass and br oad leaf plant r esidues

• 

### Ta ll gr ass v alue is closes t to empirical da ta

• Proposed residue concentr ation is 110 mg a.i./kg per 1 lb a.i./ A

• Adult dose: 32 μg a.i./bee per 1 lb a.i./ A

• Larv al dose: 13μg a.i./bee per 1 lb a.i./ A

### • 

## Assumptions and Uncertainties

• 

### Assume that tall gr ass upper bound is r epr esentative of pollen and nectar

• 

### Assume that concentr at ion fr om dir ect f oliar spr ay at time of application exc eeds later concentr at ion r esulting fr om s ystemic tr ansport U.S. Environmental Pr otection Agency **39** 

# Es tima ting Die ta ry Exposur es fo r Fo liar Spr ay

A pplic at ions

• 

## Str eng ths of pr oposed method

• 

### Ta ll gr ass upper bound concentr at ion appear s t o be r easonably conserv at iv e compared to empirical concentr at ions on pollen and nectar

# Es tima ting Die ta ry Exposur es fo r Seed Tr ea tmen ts

• 

## Description of Pr oposed Method

• 

### Assume that pes ticide concentr at ion in pollen and nectar of seed tr eated cr ops is 1 mg a.i./kg (1 μ g a.i./ g)

• No adjustment is made f or application ra te U.S. Environmental Pr otection Agency **40**

• No adjustment is made f or application ra te

• Based on EPPO’ s r ecommended scr eening v alue

• 

### Final doses calculated by multiplying 1 μ g a.i./ g by f ood intak e r ates

• Adult Dose = 0.29 μ g a.i./bee

• Larv al Dose = 0.12 μ g a.i./bee

# Es tima ting Die ta ry Exposur es fo r Seed Tr ea tmen ts

• 

## Method E va luation: empirical data f or pollen (n = 18)

• 

### 1 mg a.i./kg scr een is f act or of 28 abov e highes t concentr at ion U.S. Environmental Pr otection Agency **41**

0.1 1**C o** **n c** **e n** **t r** **a t** **i o** **n (** **m g** **a .** **i .** **/ k** **g )** 

0.0001 0.001 0.01 0.1

**Chemical C** **o n** **c e** **n t** **r a** **t i** **o n** **( m** **g a** **. i** **. /** **k g** **)**

< <

< <

# Es tima ting Die ta ry Exposur es fo r Seed Tr ea tmen ts

• 

## Method E va luation: empirical data f or nect ar (n = 6)

• 

### 1 mg a.i./kg scr een is 3 or der s of magnitude abov e empirical da ta U.S. Environmental Pr otection Agency **42**

0.1 1**C o** **n c** **e n** **t r** **a t** **i o** **n (** **m g** **a .** **i .** **/ k** **g )** 

0.0001 0.001 0.01 0.1

Clothianidin Clothianidin Imidacloprid Imidacloprid Thiamethoxam Unnamed Chem # 2 **Chemical** <

<**C o** **n c** **e n** **t r** **a t** **i o** **n (** **m g** **a .** **i .** **/ k** **g )** 

<

# Es tima ting Die ta ry Exposur es fo r Seed Tr ea tmen ts

• 

## Assumptions and Uncertainties

• 

### Assumed that pes ticides applied to seeds ar e s ystemically tr ansported

• 

### Does not account f or application r ate

• 

### Does not account f or f ate of pes ticide U.S. Environmental Pr otection Agency **43**



### • 

## Str eng ths of pr oposed method

• 

### 1 mg a.i./kg v alue is conserv at iv e r elative to empirical da ta

• By a f actor of 28 f or pollen

• By a f actor of 333 f or nect ar

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Description of Pr oposed Method

• 

### Based on Brig gs’ model (Brig gs et al. 1982, 1983)

• Predicts concentr ation in stems using:

• Octanol

- water partition coefficient (Kow)

• Concentr ation in water ( C water )

• Tr anspir ation Str eam Concentr ation F actor (TSCF) U.S. Environmental Pr otection Agency **44**

• Tr anspir ation Str eam Concentr ation F actor (TSCF)

• Calculated using Kow


#   water

LogKow stem 

## C TSCF C * 82

. 0 10 * ) 05

. 2 * 95

. 0 ( 

##   

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Description of Pr oposed Method (continued)

• 

### Includes soil w ater partitioning as pr oposed by R ya n et al. (1988)

• Re quir es or ga nic

- carbon partition coefficient (K oc) or soil partition coefficient ( Kd )

• Re quir es concentr ation in soil ( C soil ) instead of C water

• Re quir es basic soil pr operties U.S. Environmental Pr otection Agency **45**

• Re quir es basic soil pr operties

• Soil bulk density (ρ)

• Soil water content (θ)

• Fr action of or ganic carbon ( fo c ) 

#             

## foc Koc C TSCF C soil LogKow stem 

## * * * * 82

. 0 10 * ) 05

. 2 * 95

. 0 ( 

##   

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Description of Pr oposed Method (continued)

• 

### Modifications to the TSCF calculation were made by EP A to gener ate more conser vat iv e es timates of the concentr at ion in s tems (Appendix 5) U.S. Environmental Pr otection Agency **46**



### Estima **tes of median and 95**  **th** 

### per **centile TSCF values based on empirical da**  **taset reported by Briggs et al. 1982.**

0 0.2 0.4 0.6 0.8 1

- 1 0 1 2 3 4 5 Median TSCF 95th per centile TSCF

**Log Kow T** **S C** **F** 

### da **taset reported by Briggs et al. 1982.**

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Method E va luation: empirical data f or pollen (n = 14)

• 

### Model pr edictions ar e gener ally conserv at iv e compar ed to empirical da ta U.S. Environmental Pr otection Agency **47**

1.4 1.6 1.8 2**k g** **p e** **r 1** **l b** **a .** **i .** **/ A** **)**

0 0.2 0.4 0.6 0.8 1 1.2 1.4

**Chemical C** **o n** **c e** **n t** **r a** **t i** **o n** **( m** **g a** **. i** **. /** **k g** **p e** **r 1** **l b** **a .** **i .** **/ A** **)**

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Method E va luation: empirical data f or nect ar (n = 16)

• 

### Model pr edictions ar e gener ally conserv at iv e compar ed to empirical da ta U.S. Environmental Pr otection Agency **48**

1.4 1.6 1.8 2**p e** **r 1** **l b** **a .** **i .** **/ A** **)**

0 0.2 0.4 0.6 0.8 1 1.2 1.4

**Chemical C** **o n** **c e** **n t** **r a** **t i** **o n** **( m** **g a** **. i** **. /** **k g** **p e** **r 1** **l b** **a .** **i .** **/ A** **)**

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Consider ation of EPPO’ s 1 mg a.i./kg scr een

• 

### Conserv at iv e f or all but one v alue fr om empirical da ta set

• Dimethoate concentr ation in nect ar (4.82 mg a.i./kg; Lor d et al. 1968)

• High application ra te (17 lb a.i./ A) U.S. Environmental Pr otection Agency **49**

• High application ra te (17 lb a.i./ A)

• 

### Does not account f or application r ate

• 

### Does not account f or f ate of chemical

# Es tima ting Die ta ry Exposur es fo r Soil Applic ati ons

• 

## Assumptions and Uncertainties of modified Briggs’ Model

• 

### Uses s tem concentr at ions as surr og ates fo r pollen and nectar

• 

### Assumed that pes ticides applied to soil ar e s ystemically tr ansported

• 

### Da ta fr om barley only

• 

### Limited number and type of chemicals (2 classes of non

- ionic pes ticides)

• Ma y have limited application to ionic chemicals U.S. Environmental Pr otection Agency **50**

• Ma y have limited application to ionic chemicals

• 

### Xy lem based



### • 

## Str eng ths of pr oposed method

• 

### Es timates appear to be r easonably conserv at iv e

• 

### Accounts fo r some basic chemical specific par ameter s

• Application r ate

• Kow

• Ko c (or Kd )

# Summary of Pr oposed Tier I Exposur e Assessmen t Methods U.S. Environmental Pr otection Agency **51**

**Application Ty**  **pe Exposure** 

**Ro ute**  **Method Description Exposure Estimate**  **Ex ample Dose**  **( μ**  **g a.i./bee )**  **Fr om 1 lb a.i./** 

**A application**  **Adult Bees** Foliar spr ay Contact Koch and We isser (1997) Max (2.7 μ g a.i./bee )*App. ra te 2.7 Foliar spr ay Diet T

- REX tall gr ass upper bound (32 μ g a.i./bee) *App. ra te 32 Foliar spr ay Diet T

- REX tall gr ass upper bound (32 μ g a.i./bee) *App. ra te 32 Seed Tr eatment Diet EPPO scr een 0.29 μ g a.i./bee 0.29 Soil Tr eatment Diet Modified Briggs model (Briggs EE C )( 0.29 g/ day ) 0.42

**Larv ae**  Foliar spr ay Diet T

- REX tall gr ass upper bound (13 μ g a.i./bee) *App. ra te 13 Seed Tr eatment Diet EPPO scr een 0.12 μ g a.i./bee 0.12 Soil Tr eatment Diet Modified Briggs model (Briggs EE C )*( 0.12 g/ day ) 0.18

# Summary of Tier I Me thods fo r es tima ting pes ticide concen tr ati ons on bees and in pollen and nect ar

• 

## Es timated concentr ations on bees, pollen and nectar ar e re asonably conser vat iv e r ela tiv e t o empirical data U.S. Environmental Pr otection Agency **52**



### • 

## As mor e data become a va ilable, EP A ma y r e - ev aluate methods

• 

## Interested in SAP comments on the pr oposed methods f or es timating tier 1 e xposur e v alues

• 

### Contact e xposur e: char ge question 4

• 

### Dietary e xposur e: char ge question 6

# Ques tions U.S. Environmental Pr otection Agency **53**



# Ques tions