OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION 

### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460



## RE : Meeting between Dow AgroScience s (DAS) and EPA to Discuss DAS’ Recently Completed Chlorpyrifos Higher Tier Ecological Risk Assessment

List of Documents

1. Meeting Summary Page 1

2. Meeting Sign in Sheet Page 2

3. DAS PowerPoint Presentation Page 3

Meeting Summary

On Wednesday, August 21, 2013 , EPA’s Office of Pesticide Programs met with Dow AgroSciences (DAS) and their consultants for a presentation of DAS ’ recently completed chlorpyrifos higher t ier ecological risk assessment. Due to the breadth of the material covered in

their risk assessment, the presentation touched on only a few areas. Some of the a reas that were presented wer e f ate in the environment and long

- range atmospheric transport

, refined avian risk assessment for flowable and granular formulations, e xposures and risks to aquatic organisms

, and risk to pollinators. The DAS ecological risk ass essment did not address endangered species.

## 8/21/2013

1 1 DOW CONFIDENTIAL

- Do not share

without permission



# Authors

– Panel Members

John P. Giesy 1 

# , Keith R. Solomon 2 

# , Donald 

# Mackay 3 

# , Jeffery M Giddings 4 

# , Marty Williams 5



# , Dwayne Moore 6 

# , John Purdy 7 

# , Chris Cutler 8

1. Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada

2. Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, ON, Canada.

3. DMER , Peterborough, ON, Canada

4. Compliance Services International, Rochester, MA, USA

5. Waterborne Environmental, Leesburg, VA, USA

6. Intrinsic Environmental Services, New Gloucester, ME, USA

7. Abacus Consulting Services Ltd., Campbellville , ON Canada

8. Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada

2

## 8/21/2013

2 

# Communication to the scientific

community

► Six peer

- reviewed papers in Reviews of
Environmental Contamination and Toxicology plus an overview paper

– executive summary (accepted or in 

# revision).

► Special symposium at the ACS meetings in Indianapolis on Sept 10, 2013

► Other presentations, such as at SETAC

3



# Outline

► Approach

► Properties and uses of chlorpyrifos in the United States

► Fate in the environment and long

- range atmospheric transport of the organophosphorus insecticide, chlorpyrifos and its oxon

► Refined avian risk assessment for flowable and granular 

## formulations of chlorpyrifos in North America

► Exposures of aquatic organisms resulting from the use of chlorpyrifos in North America

► Risks to aquatic organisms from the use of chlorpyrifos

in North America

► Risk to pollinators from the use of chlorpyrifos in North

America

4

## 8/21/2013

3 

# Approach

► Build on the previous assessments

Giesy JP, Solomon KR, Coates JR, Dixon KR, Giddings JM, Kenaga EE. 1999.

Reviews of Environmental Contamination and Toxicology 160:1

- 129

Solomon KR, Giesy JP, Kendall RJ, Best LB, Coats JR, Dixon KR, Hooper MJ, Kenaga EE, McMurry ST. 2001. Human and Ecological Risk Assessment 7:497

- 632

5



# Approach

► Build on the previous assessments

► Focus on current uses supported by DAS (agricultural)

► Focus on new label rates and directions

► Focus on refined upper tiers of risk assessment, (no simple hazard quotients)

► Use new methods for assessing risks

- models

► Exposures and risks to birds

► Exposures in surface waters



## ► Respond to newly identified concerns

► Potential for long

- range transport

► The active metabolite, chlorpyrifos

- oxon

► Risks to pollinators

► POPs and PBT (Issue raised in POPSRC and EC 1107/2009)

6

## 8/21/2013

4 

# Overview of conclusions 1

► Degradation is generally rapid at rates used in agriculture.

► Important and widely used in agriculture.

► Use has decreased by about 50% since 2000 does not show strong seasonality.

► Concentrations in semi

- remote locations less than toxicity values.

► Characteristic Travel Distance is between 62 and 244



## km.

► CPY does not trigger POPs or LRT. CPYO triggers LRT only but P OV 

## is small and shows that LRT is not an issue.

► CPY triggers T but not P or B under EC 1107.

7



# Overview of conclusions 2

► Models for exposure to liquid and granular formulations
based on refinements of TIM V1 and 2.

► For flowable CPY, some acute risks for sensitive birds and greater rates of application

– for most birds and

most uses risks are de minimis.

► Chronic risk not an issue.

► Risks from granular de minimis for all species.

► Field and incident data consistent with conclusions of

model.

► Concentrations of CPY in surface water have declined
since before 2000.

► CPYO not measurable in surface waters.

8

## 8/21/2013

5 

# Overview of conclusions 3

► Modeled exposures consistent with measured values in focus watersheds (GA, MI, CA ). Median durations above 0.1 μg/L were ≤ 2 d

. ► Risks to aquatic organisms have decreased since 2000.

► Risks from CPY in benthos and CPYO de minimis.

► Risks from CPY in aquatic organisms de minimis except for low risks in Crustacea in high

- use CA focus watershed.

► Consistent with incident reports.



## ► CPY is toxic to bees by direct contact

- mitigated by label.

► Nectar and pollen most important routes of exposure but little risks predicted by Tier

- 2 assessment.

► Negligible risks from water, propolis, and wax.

► Incident reports rare, especially after 2000.

9



# Properties and uses of 

# chlorpyrifos in the United States

RA 2

10

## 8/21/2013

6 

# Purpose

► Provide background information for discussion in the other chapters

► Chemical and physical properties

► Metabolites and breakdown products

► Dissipation

► Mode of action

► Formulations

► Use and timing

11



# Chemical and physical properties

► Fate in air and long

- range transport

– see RA 3 (Mackay et al, 2013).

► Fate in water, soil, and sediments

► Build on previous papers ( Racke 1993) and
Gebremariam et al. 2012.



# ► Select most appropriate values to inform the ERA and modeling.

12

## 8/21/2013

7 CO 2 , N 2 , Cl

CPY, chlorpyrifos

CPYO, chlorpyrifos

- oxon Desethyl chlorpyrifos

TMP, trichloromethoxypyridine TCP, trichloropyridinol 

# Transformation, metabolism and

degradation

13 Figure 1



# Physical

Parameter Values for Chlorpyrifos

Chemical Name O,O

- diethyl o

- (3,5,6

- trichloro

- 2

- pyridyl

phosphorothioate

Chemical Abstracts Service

(CAS) Registry Number 2921

- 88

- 2

Empirical formula C 9 

### H 11 

### Cl 3 

### NO 3 

### PS

USEPA Pesticide Code (PC #) 59101

Smiles notation S=P(OC1=NC(=C(C=C1Cl)Cl)Cl)(OCC)OCC

Molecular mass 350.6 g mol

- 1



### Vapor pressure (25 ° C) 1.73 x10

- 5 

### torr

Water solubility (20 ° C) 0.73 mg L

- 1



### Henry’s Law Constant 1.10 x 10

- 5 

### atm m - 3 

### mol

- 1



### Log K OW 

### 5.0

14 Figure 1

## 8/21/2013

8 

# Chemical

Parameter Values

Hydrolysis (t1⁄2) pH 5: 73 d

pH 7: 72 d pH 9: 16 d



### Aqueous photolysis (t1⁄2) 30 d



### Aerobic soil metabolism (t1⁄2) 1.9

- 1576 d



### Aerobic aquatic metabolism (t1⁄2) 22

- 51 d



### Anaerobic soil metabolism (t1⁄2) 15 and 58 d



### Anaerobic aquatic metabolism (t1⁄2) 39 and 51 d



### Soil adsorption coefficient K OC 

### 973

– 31,000 mL g

- 1



### Terrestrial field dissipation (t1⁄2) 1.3

- 120 d

15 Figure 1



### Measured CPY

Aerobic soil

metabolism

Labile CPY Adsorbed
CPY

Metabolites F 1

F 2 F 3 

# Biphasic degradation in soil

5

100 200 300 400 4

3

2

0 1

0 

### Time (d) Ln % concentration 

## Dissipation in Barnes soil ( Bidlack , 1979)

Phase I, t 1⁄2 = 25.3 d

Phase II, t 1⁄2 = 154 d

16 Figure 2 & Figure SI C

- 1

## 8/21/2013

9 

# Half

- lives calculated from 2

- compartment model

Soil Reported t1⁄2 Calculated t1⁄2 from 2

- compartment model Group



### Commerce, MI 11 11 2

Barnes, ND 22 22 2

Miami, IN 24 18 2

Caitlin, IL 34 28 2

Marcham, UK 43 9 2

Thessaloniki, GR 46 31 1



### Charentilly, FR 95 93 1

Norfolk, VA 102 57 1

Stockton, CA 107 96 1

Cuckney UK 111 84 1

German 2:3 141 99 1

17 Table 3



# pH

- dependence of degradation in

soil

Group

- 1 soils; half

- lives >30 days and pH dependent (abiotic degradation) Group

- 2 soils; shorter half

- lives with much weaker correlation to pH (biotic degradation)

18 

## pH 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 Half - life (d)



### 0 20 40 60 80 100 120

Group 1

Group 2

Figure 2

## 8/21/2013

10 Time (days) 0 100 200 300 400 Residues (% of applied radioactivity)

0 20 40 60 80 100

Adsorbed CPY

Dissolved CPY

Measured CPY

Metabolites 

# ModelMaker optimization results

–

Barnes soil

Figure SI C

- 3



# Half

- lives chosen for the modeling
in surface waters

► The highest half

- life among the US soils in each group was selected as a conservative value to represent the group in the PRZM/EXAMS model

runs

► Stockton (CA) soil 96 d

► Caitlin soil (IL) 28 d

20

## 8/21/2013

11 N C l C l C l

O P S O C H 2 C H 3

O C H 2 C H 3 Chlorpyrifos Chlorpyrifos

- oxon [O]



### AChE OH k 1

k 3 k 2 Phosphorylation



### AChE O P O O C H 2 C H 3

O C H 2 C H 3



### AChE OH

Hydrolysis and

reactivation N C l C l C l

O P O O C H 2 C H 3

O C H 2 C H 3



### AChE O P O O H

O C H 2 C H 3 k

- 1

Aging (hydrolysis) Aged enzyme cannot
be reactivated

Recovered enzyme
returns to normal
function

N C l C l C l

O H

TCP 

### + 

# Mechanism of action

21 Figure 4



# Relevance of MoA

► Animals with AChE are the most sensitive

► Plants much less sensitive

► Some groups of animals are more sensitive than

others

► Metabolism to less toxic substances (TK)

► Rate of recovery (TD)

22

## 8/21/2013

12 

# Interactions with other pesticides

► With other AChE inhibiting insecticides.

► Additivity based on potency.



# ► With other pesticides that induce activation of CPY to CPYO (e.g., atrazine).

► Requires temporal co

- occurrence at appropriate

concentrations.



# ► Probability of co

- occurrence is small

– excluded
from the assessment.

N C l C l C l

O P S O C H 2 C H 3

O C H 2 C H 3 Chlorpyrifos Chlorpyrifos

- oxon [O]

N C l C l C l

O P O O C H 2 C H 3

O C H 2 C H 3

23



# Products evaluated and use

► Lorsban

- 4E,

- Advanced,

- 15G, and

- 50W.

► One of the most widely used insecticides (globally)

► Estimates of annual use in the USA since 2008 range from 3.2 to 4.1 M kg

► Decrease of 50% since 2000

► No more residential or landscape uses

► Changes in agricultural production (GMO) and the

introduction of new insecticides 24

## 8/21/2013

13 

# Use per crop (2007)

0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000 1,600,000 1,800,000 2,000,000



# More than half of use is in soybeans and corn Pounds

25 From Table 4



# Timing (cropped all year)

Crop and location Months of the year in which CPY is applied

J F M A M J J A S O N D

Alfalfa, warmer states (CA, AZ, etc.)

Cooler states

Southern MO

Northern MO

Apple tree trunks

Asparagus CA only Southern desert

Delta

Central coast

Other U.S.

Brassica (cole) leafy vegetables

Brussels sprouts

Carrots for seed OR & WA

Christmas tree

Citrus orchard floors

Subset of Table 5 26 

# ► No strong seasonality to the use of CPY

## 8/21/2013

14 

# Timing (cropped part of year)

Usual Planting and Harvesting Dates for U.S. Field Crops Crop in field, location, and use of CPY Months of the year in which CPY is applied

J F M A M J J A S O N D

Corn, Southern states in field

Use of CPY

Northern states in field

Use of CPY

Cotton, Southern areas in field

Use of CPY

Northern areas + CA in field

Use of CPY

Peanuts, in field

Use of CPY

Peppermint and Spearmint, in field

Use of CPY

Subset of Table 6 27



# Timing

► Timing in relation to local conditions can
influence fate in the environment.

► No strong seasonality to the use of CPY

► Somewhat greater use in the winter months in tree crops in California

► Somewhat greater use in the summer field crops



## such as corn in the summer months

28

## 8/21/2013

15 

# The bottom line

► In general, short dissipation times via:

► Volatilization,

► Photolysis,

► Abiotic hydrolysis,

► Microbial degradation



# ► Degradation varies with rate of use

► Degradation more rapid in field than laboratory



# ► Not systemic

► Important and widely used in agriculture

► Use has decreased by > 50% since 2000

► No strong seasonality in use

29



# Fate in the environment and long

- range atmospheric transport of the organophosphorus

insecticide chlorpyrifos and its



# oxon

RA 3

30

## 8/21/2013

16 0 12 24 48 96 182 364 728 1456 Concentration



### Hours after entry to the environment Soils and

sediments Aquatic organisms Birds and pollinators Long

- range transport in air

............ Photolysis and breakdown in the troposphere and on surfaces

Absorption and adsorption to soils and sediments

Degradation by chemical and biological pathways 

# Fate

31 Figure 1



# Occurrence of CPY in air

Location and dates of sampling Concentration (ng m

- 3 )

CANCUP data for 8 sites in Canada 2004

- 5, values range from areas of application
to distant areas 0.08 to 22

Passive air samples in Ontario 2003

- 5 0.0003 to 0.06; median 0.007; 73% Frq . of Dtctn

. Iowa 2000

- 2 Average 1.0, 19% FOD 1.4 at 1A

- AMSite , 0.88

at Hills Mississippi River Valley 1994 0.43 Chesapeake Bay 2000 0.015

- 0.670 Median 0.110 FOD 87%

Bratt’s Lake ( Saskatchewan close to area of use)
Abbotsford (British Colombia, lesser use) 10 to 100 with 3 concentrations exceeding 100 and a maximum of 250 in Aug 2003
Concentrations all < 0.26 in 2004 and 2005.

Mississippi River Valley FOD 93, MS 35%, Iowa City 90%, Cedar Rapids 50%, Minneapolis 10%, Princeton MN 3%

Central Valley (CA) and Sierra Nevada, CPY up to 180 and CPYO up to 54, lesser concentrations in Sequoia NP. CPY and CPYO in air in Sequoia NP 0.16 to 17.5

Table 1 32

## 8/21/2013

17 

# Occurrence of CPY in rain and snow

Location and dates of sampling Concentration in ng L

- 1



### Chesapeake Bay 2000 Rain; 0.97

- 29 average 4.8, FOD 14%. Wet flux, 190 ngm

- 2 

### event Total 6100 ng m

- 2



### , 1.1 kg/year

Svalbard Ice Cap 1979

– 1986 Ice, peak concentration 16.2 at ~ 15 m

Delaware/Maryland April

- Sept 2000

- 2003 Rain; 1.0 to 29 average 1.0 39% FOD.

Fluxes ~ 610

- 1750 average 1.0

- 4.5 ng m

- 2



### 7 US National Parks March

- April

2003 Snow in Sequoia NP; 2.8, 1.3 Other National Parks; 0.033 ~ 0.05 ~ 0.5 ~

0.02 ~ 0.02 and 0.03 Deposition in Sequoia NP; 2600 ng m

- 2 

### Other parks; 25, 65, 35, 30, 14, and 4 ng m

- 2 

### Correlations with altitude and distance, 75, 150, 300 km from sources

Table 2 33



# Occurrence of CPY in other media

Location and dates of sampling Concentration in ng g

- 1 dw unless indicated otherwise

Sierra Nevada CA 2785 to 3375
m elevation 2004/5 Water; all concentrations in water were <0.07 ng L

- 1 Sediment;

0.043 to 3.478 median 0.107.
0.285 to 12.44 median 1.73.
0.011 to 2.276 median 0.101.
0.499 to 10.717 median 1.372. Tadpoles; 2.224 to 156, median 22.2 ng g

- 1 lipid 2.741 to 68.4, median 19.9 ng g

- 1 lipid Lassen National Park, CA, 25 km from the San Joaquin Valley edge Tadpoles of Pacific tree frog ( Hyla regilla ); 10 to 17 ng g

- 1 ww

Kaweah, Kings, and Kern
Watersheds 43

- 85 km from the San Joaquin Valley edge Tadpoles of Pacific tree frog ( Hyla regilla ); <0.6 ng g

- 1 ww

Thirty Canadian lakes 1999

- 2001 Lake water appln region; 0.28

- 1.0 mean 0.65 ng L

- 1

. Lake water remote regions <0.017

- 2.9 mean 0.82 ng L

- 1

. Lake water, subarctic; <0.017

- <0.017 ng L

- 1 Lake water, arctic; <0.017

- 1.6 mean 0.27 ng L

- 1

. Ontario 2003/5. Lake water; <0.002 to 0.5 ng L

- 1 median 0.02, 77% FOD. Rain; <0.004 to 43 ng L

- 1 median 0.76, 80% FOD. Zooplankton; <0.003

- 0.08, GM 0.004, 0.005 ng g

- 1 ww. BAF in Zooplankton (GM) 70 ( ww ), 3300 (lipid wt ). Table 3 34

## 8/21/2013

18 

# Occurrence of CPY in other media (2)

Location and dates of sampling Concentration in ng g

- 1 

### dw unless
indicated otherwise Chesapeake Bay, 2000 0.51

- 4.6

Lichen in Yosemite NP 2003

- 2005 0.92 ng g

- 1 

### , 1.7 ng g

- 1



### Pine needles in Sequoia NP, 1994 10

- 125 ng g

- 1 

### dw

Sequoia NP, 1996

- 1997 Dry deposition; 0.2

- 24ng m

- 2 

### day

- 1



### . Surface water 0.2

- 122 ng L

- 1



### .

Table 3 35



# Summary of measured values in semi

remote locations

From Table 4 36 Air

μ g m - 3 Rain

μ g L

- 1 

### 15

14

36

27

8

Snow

μ g L

- 1 Water

μ g L

- 1 Sediment

μ g g - 1 Soil

μ g g - 1 Biota

μ g g - 1 ug

10

- 6 10

- 5 10

- 4 10

- 3 10

- 2 10

- 1 10 0 10 1 10 2 10 3



### 20



### 40

20

20

0 11



### 17

11

61

0 0

46

27

10

17 0

20

40

40

0 0



### 0

100

0

0 0



### 10

10

80

0 

### ?

HC5 Crustacea H. azteca
LC50

? Toxicity

values

Percent


### of samples

## 8/21/2013

19 

# Key physical chemical properties

modeling LRT

Property of CPY Units Value
Melting point (mp) ° C 42

Molar mass g/mol 350.6


### Fugacity ratio (FR)

- 0.68
Vapor pressure (VP) of solid Pa 0.0023
Vapor pressure of sub

- cooled liquid Pa 0.0034
Solubility of solid in water g m - 3 

### or mg L

- 1 

### 0.73
Solubility of sub

- cooled solid g m - 3 

### 1.07
Henry’s Law constant Pa m

- 3 

### mol

- 1 

### 1.11

Air

- water partition coeff . K AW 

### - 0.00045 Log is

- 3.35

Octanol

- water partition coeff. K OW 

### - 100,000 Log is 5.0

Octanol

- air partition coeff. K OA 

### - 2.2 × 10 8 

### log is 8.34

Organic carbon

- water partition coeff.

K OC 

### L/kg 8,500 Log is 3.93

Table 5 37



# Reaction half

- lives (CPY for LRT)

Medium Value Comment

•OH radical reaction in air 9.1 x 10

- 11 

### cm 3



### molecules

- 1 

### s - 1 

### 2 nd 

### order rate

constant

Half

- life in air 1.4 h

,

3.0 h •OH radical conc. of

1.5 × 10 6 

### m - 3



### •OH radical conc. of

0.7 × 10 6 

### m - 3



### Half

- life in soil 7 to 30 d 168

- 720 h

Half

- life in surface water 30 to 50 d 720

- 1200 h

Half

- life in sediment 50 to 150 d 1200

- 3600 h

Table 6 38

## 8/21/2013

20 

# Properties of CPYO (for LRT)

Property Value

Molar mass 334.6

Vapor pressure 0.00088 Pa

Solubility in water 26 mg L

- 1


## Octanol water partition
coefficient K OW 

## 776 Log is 2.89

Half

- life in air 11 d

Half

- life in soil 9 to 30 d

Half

- life in water 13.2 d

Half

- life in sediment 132 d

Table 7 39



# TAPL3 LRT model (t 1⁄2 = 3 h)

CTD = 62 km

40 

## CTD = 244 km t1⁄2 = 12 h

Figure 2

## 8/21/2013

21 Distance (km) 0 200 400 600 800 1000 Concentration (ng m - 3 )

10

- 5 10

- 4 10

- 3 10

- 2 10

- 1 10 0 10 1 10 2

Chlorpyrifos Chlorpyrifos

- oxon 0 2 4 8 12 16 20 67



## Hours 

# Medium

- range transport

Figure 4

CTD = 62 km

41



# TAPL3 LRT model (t 1⁄2 = 12 h)

CTD = 244 km 42 Figure 3

## 8/21/2013

22 

# The bottom line

► CPY and CPYO detected in various

environmental media

► Mass balance model

► Some transport over shorter distances

► Transformation to CPYO in atmosphere

► CPY is better parameterized than CPYO

► Concentrations, in semi

- remote locations, not of 

## toxicological concern

43



# POPs and PBTs
Criteria for POPs

UNECE , 1996; UNEP

, 2001 

### Criteria for persistence (P ) Criteria for

bioaccumulative (B ) Criteria for toxicity (T) Potential for long

range transport (LRT)


### Water : DT50 >

60 d
Sediment:



### DT50 > 180 d
Soil: DT50 >

180 d BCF > 5,000 or Log

KOW > 5 Other, e.g., very



### toxic or

bioaccumulation in nontarget species No specific

criteria other than “significant


### adverse effects” Air : DT50 > 2 d or

modeling or monitoring data



### which shows long

- range transport

44 Table 12

## 8/21/2013

23 

# Criteria for PBT (EC1107/2009)

Persistence (P) Bioaccumulation (B) Toxicity (T)

Marine water: t1⁄2 > 60 d;

Fresh water t1⁄2 > 40 d

Marine sediment: t1⁄2 >180 d

Freshwater sediment: t1⁄2 >

120 d
Soil: t1⁄2 >120 d BCF > 2,000 in aquatic species Chronic NOEC < 0.01 mg/L or is a carcinogen, mutagen, or toxic for reproduction, or
other evidence of toxicity

Off J Europ Commun 52:1

- 50. 

# Which values are compared to the criteria? 

# EC 1107/2009 does not provide guidance. Because of averaging in the environment, mean or geometric mean values have been recommended (SANCO, 2012).

45 Table 12



# Half

- life in water

► T 1⁄2 deg 

# from 1.5

to 142 d, pH 5

- 9

► pH and Cu ++ 

# the
main drivers

► GM = 29 d

► T 1⁄2 dis 

## in field = 4

- 10 d

► GM = 5 d



# Geomean values do not trigger the
criteria for POPs or

BPTs 29

46 SI Table 1

## 8/21/2013

24 

# Half

- life in soils

► T 1⁄2 from 1.9 to 1,575 d in the laboratory and 1.5
to 120 d in the field.

► Lab GM = 32

► Field GM = 22



# ► Temp and pH major
drivers

Geomean values do not trigger the criteria
for POPs or BPTs Half

- life of chlorpyrifos in soil (d) 0.1 1 10 100 1000 10000 Percent rank

1 2 5 10 20 30 50 70 80 90 95 98 99

Laboratory

Field L 32 F 22

47 SI Table 2 & 3



# Half

- life in sediments

► T 1⁄2 from 6 to 223 d in laboratory.

► GM = 39



# Geomean values do not trigger the criteria
for POPs or BPTs 39

48 SI Table 4

## 8/21/2013

25 

# BCF

► BCF from 396 to

5100 in the laboratory and 100
to 4667 in the field.

► Lab GM = 848

► Field GM = 935



# Geomean values do 

# not trigger the criteria
for POPs or BPTs L 848

F 935

49 SI Table 5



# POPs and long

- range transport

► Not a POP on the basis of P, and B.

► No “significant adverse effects” in areas of use or remote regions.

► The half

- life of CPY in the atmosphere does not exceed the trigger value of 2 d for LRT.

► CPY is found at distances from areas of application and even in remote locations but the
concentrations in air, rain and snow, and aquatic

and terrestrial media, and biota are small and less than the threshold of toxicity for terrestrial and aquatic organisms.

► Does not trigger LRT

50

## 8/21/2013

26 

# CPYO as a POP

► CPYO does not trigger the criteria for persistence in water, soil, or sediment

. ► No data were available for BCF, but studies with ring

- labelled CPY provide equivalency for CPYO

– does not trigger B.

► Toxicity for CPYO subsumed in that of CPY and it does not trigger “significant adverse effects”.

► Half

- life in air is >2 d

– triggers LRT

► Found at moderate distances from areas of application



## ► Concentrations in environmental media < threshold of toxicity for terrestrial and aquatic organisms.

► Partitioning to and reactivity in water reduces P OV 

## , LRT

not an issue.
51



# PBT (EC 1107/2009)

► Does not trigger P and B.

► The most sensitive chronic NOEC reported for aquatic organisms of 0.005 μg L

- 1 

# and triggers
the T criteria for PBTs.

► Since CPY is an insecticide, this is expected.

► The key question is the relevance of this to exposures in the general environment and the lack of significant
adverse effects from the ERAs for birds, pollinators, and aquatic organisms.

52

## 8/21/2013

27 

# Refined avian risk assessment for flowable and granular formulations of chlorpyrifos in

North America

RA 4

53



# LiquidPARAM

► LiquidPARAM

► Liquid Pesticide Avian Risk Assessment Model



# ► Incorporates parts of EPA TIM v1 and v2 and many of the recommendations from the EPA
SAPs (2001, 2004)

► Predicts fate of each of 20 birds on each of 1000 fields during 60 days following initial application

► One

- hour time step

► Probabilistic exposure and effects

► Used in ERA of flowable carbofuran

54

## 8/21/2013

28 

# Overview

► Flowable chlorpyrifos

► Exposure scenarios and conceptual model

► Avian model to assess risks of flowable CPY ( LiquidPARAM )

► Methods and results



# ► Granular chlorpyrifos

► Exposure scenarios and conceptual model

► Avian model to assess risks of granular CPY ( GranPARAM )

► Methods and results



# ► Other lines of evidence

► Discussion

55



# Focal species

56 Common name Scientific name Feeding preferences

Abert’s towhee Pipilo aberti Insects and seeds from the ground

American crow Corvus brachyrhynchos Omnivorous and opportunistic ground

feeder

American robin Turdus migratorius Mainly insects and fruit
Blue grosbeak Passerina caerulea Mainly insects

Common pheasant Phasianus colchicus Agricultural grains and other vegetation,
insects, and seeds

Dickcissel Spiza americana Ground

- dwelling arthropods and seeds

Horned lark Eremophilia alpestris Almost entirely of seeds in the winter
months, but also includes ground

- dwelling insects in the spring, summer and fall

Indigo bunting Passerina cyanea Seeds, berries, and insects gleaned from
foliage

Killdeer Charadrius vociferous Almost entirely arthropods with a small
portion of seeds Mourning dove Zenaida macroura Only seeds

Northern bobwhite Colinus virginianus Insects and seeds

Red

- winged blackbird Agelaius phoeniceus Insects and seeds

Vesper sparrow Pooecetes gramineus Grasses, seeds and foliage

- dwelling

insects

Western meadowlark Sturnella neglecta Mainly insects, with a small proportion of
seeds and grains

Table 1

## 8/21/2013

29 

# Exposure Scenarios: Lorsban Advanced

Crop Use pattern Focal bird species

Alfalfa Southern Plains

- 0.94 lb./ A and 0.47

lb /A applied broadcast with 10 d

interval American widgeon, Canada goose,
Dickcissel, Mourning dove, Red

- winged
blackbird, Vesper sparrow, Western

meadowlark

Almond California

- 1.88 lb./ A applied air

- blast

post

- plant 2X (May, hull

- split) with 10 d

interval Abert's towhee, Blue grosbeak, Common
crow, Mourning dove, Red

- winged

blackbird

Apple Northwest

- 1.88 lb./ A applied ai

- rblast

delayed dormant to petal fall Blue grosbeak, Common crow, Mourning
dove, Red

- winged blackbird

Broccoli California

- 2.11 lb./A applied band at

plant and post

- plant 3X with 10 d

interval Common crow, Horned lark, Mourning
dove, Red

- winged blackbird

Cherry Michigan

- 1.88 lb./ A applied broadcast

post

- plant Blue grosbeak, Common crow, Mourning
dove, Red

- winged blackbird

Corn Midwest

- 1 lb./ A applied broadcast at

plant and band post

- plant 3X with 10 d

interval American robin, Horned lark, Killdeer, Mourning dove, Northern bobwhite, Red

winged blackbird, Vesper sparrow

57 Table 2



# Exposure Scenarios: Lorsban Advanced (2)

Crop Use Pattern Focal Bird Species

Grape California

- 1.88 lb./A applied air

- blast

prior to bud break Blue grosbeak, Common crow, Mourning
dove, Northern bobwhite, Red

- winged

blackbird

Grapefruit Florida

- 2.5 lb./A applied air

- blast post

plant (Apr

- Jun) Blue grosbeak, Common crow, Mourning
dove, Northern bobwhite, Red

- winged

blackbird

Orange California

- 5.6 lb./ A applied air

- blast

post

- plant (May

- Aug) Abert's towhee, Blue grosbeak, Common
crow, Mourning dove, Red

- winged

blackbird

Pecan Georgia

- 0.94 lb./ A applied air

- blast 3X

with 10 d interval Blue grosbeak, Common crow, Mourning
dove, Northern bobwhite, Red

- winged

blackbird

Soybean Louisiana

- 0.94 lb./ A applied broadcast

post

- plant 3X with 14 d interval (May

Aug) Blue grosbeak, Dickcissel, Horned lark, Indigo bunting, Mourning dove, Red

winged blackbird

Sweet corn Florida

- 1 lb./ A applied broadcast at

plant and band post

- plant 3X with 10 d

interval Common crow, Mourning dove, Northern
bobwhite, Red

- winged blackbird 58 Table 1

## 8/21/2013

30 

# Conceptual model for exposures and
effects of flowable CPY

59 Runoff/Erosion Application to agricultural fields

Effects Receptors Media Routes of transport Releases

Degradation to biologically inactive compounds

Uptake Spray drift Direct deposition Leaching &

sub

- surface
flow

Puddles Terrestrial biota (invertebrates & seeds

Ingestion

Birds

Reduced

survival

Figure 1



### Hourly pesticide dose

Concentrations in food

and water over time

Fate properties

Degradation

rates Pesticide use scenario

Initial concentrations

In food and water

Ingestion rates

over time

Hourly retained dose Species of interest

Foraging

behavior Rate of

metabolism 

# LiquidPARAM exposure

60 Figure 4

## 8/21/2013

31 Alive Dead

Yes No



### Repeat for 20 birds

Repeat for 1000 Fields Hourly

retained dose

SSD approach

Randomly select from

dose

- response curve No

Yes 

### Species

- specific

dose

- response curve ?

Randomly select from

5 th 

### , 50 th 

### and 95 th 

### centile

dose

- response curves Maximum

retained dose

Exposure > Effects? 

# LiquidPARAM acute risk

61 Figure 4



# Refinement of LiquidPARAM (vs. TIM 1)

► New focal species added.



## ► One

- h time

- step.

► Bird can forage on and off the field at each time

- step.

► Nomograms specific to the pesticide, where data permit.

► Separate nomograms for orchards and field/row crops.

► Matrix effects considered.

► Separate RUDs for different functional groups of invertebrates (flying, foliage

- dwelling, soil surface, below ground ).

► Diets of bird species refined to 4 functional groups of
invertebrates instead of “all invertebrates”.



## ► Avoidance split into gustatory and symptomatic.

► Up to 4 applications/season, model extended to 60 d, chronic

exposure, effects, and risk can be assessed.

62

## 8/21/2013

32 

# Derivation of CPY

- specific RUDs

► Only data from sprayable application studies used

► Insufficient data for row crops, RUDs for row and field crop were merged

► Results for field and row crops weighted to sample size

► Data collected adjacent to the field or off

- field not used

► Data from dislodgeable residue measurements not used as herbivorous birds consume vegetative matter



## ► Day

- 0 samples used for vegetative RUDs and peak of day

- 0 and

- 1 samples used for invertebrate RUDs

► In absence of data, used Kenaga nomogram ( blue italics )

► When n = 1 , standard deviation calculated from coefficient of variation for all other dietary items within the crop type ( red bold )

► For drinking water, assumed puddles occur 1 d after application and that puddle concentrations equal day

- 1 runoff concentrations

63



# Recommended RUDs

Crop type Dietary item RUD (mg ai /kg ww/lb ai /A)

Mean Standard deviation n

Orchards Soil surface invertebrates 1.58 0.933 13

Below ground invertebrates 0.14 0.079 1
Foliage

- dwelling invertebrates 14.6 12.8 11
Flying invertebrates 0.145 0.082 1

Grass 84.8 60.3 18
Broadleaf forage 30.7 9.1 5

Seeds 0.085 0.048 1

Fruits 0.746 0.250 12

Field and row
crops Soil surface invertebrates 4.16 6.70 15

Below ground invertebrates 1.48 1.60 1
Foliage

- dwelling invertebrates 13.7 6.77 6
Flying invertebrates 0.13 0.14 1

Grass 148 205 12
Broadleaf forage 122 68.8 5

Seeds 4.55 2.94 4

Fruits 5.52 9.8 108

64 SI Table 3

## 8/21/2013

33 

# RUDs for o rchards

0.01 0.1 1 10 100 1000 RUDs (mg ai/kg - ww/lb - ai/A)



### Dietary Item Chlorpyrifos Kenaga

65 From SI Table 3



# RUDs for field and row crops

0 1 10 100 1000 RUDs (mg ai/kg - ww/lb - ai/A)



### Dietary Item Chlorpyrifos

Kenaga

66

## 8/21/2013

34 

# Avoidance studies

► Three studies available

► Wildlife International (1978) study on mallards

► Bennett (1989) study on northern bobwhite

► Stafford (2010) study on northern bobwhite



# ► For each study, we calculated

► % reduction in diet from treated fields due to

adverse taste or smell

► % reduction in food intake rate due to sickness

67



# Avoidance: Gustatory

y = 0.0654ln(x)

- 0.3016
R2 = 0.2336 y = 0.1868ln(x)

- 0.5224
R2 = 0.8948 y = 0.159ln(x)

- 0.1498
R2 = 0.7984

- 0.4 - 0.2 0.0 0.2 0.4 0.6 0.8 1.0

0 1000 2000 3000 4000 5000 Bias to clean diet

Dietary concentration (mg ai /kg ww) Bobwhite (Stafford, 2010)

Bobwhite (Bennett, 1989)

Mallard (Fink et al., 1980) (Wildlife International, 1978)

68 SI Figure 6

## 8/21/2013

35 

# Avoidance: Symptomatic

0 50 100 150 200 250 300

0 10 20 30 40 50 Normalized FIR (g diet/kg bw/d)

Normalized dose (mg ai /kg bw /d) Bobwhite (Bennett, 1989)

Stafford (2010)

Mallard (Fink, 1980) (Wildlife International, 1978)

69 SI Figure 7



# Avoidance component

► Gustatory (taste or smell)

► Birds avoided treated feed at highest test concentrations

► Repellency not observed in Stafford (2010) study likely

due to lower test concentrations

► In LiquidPARAM , we used Bennett (1989) repellency model because it had the strongest relationship and was slightly more conservative than Wildlife International (1978) model



# ► Symptomatic ( sickness)

► No apparent relationship for any of the 3 studies

► Set to zero in LiquidPARAM

70

## 8/21/2013

36 

# Effects assessment

► Used similar approach to EPA for estimation of

acute risk (same as TIM)

► Dose

- response curve for focal species with acceptable toxicity data

► Acute oral gavage studies only

► Canada goose, northern bobwhite, red

- winged



## blackbird



# ► Species sensitivity approach (SSD) for remaining focal species (same as TIM)

► SSD based on acute oral gavage studies

► Derived hypothetical dose

- response curve for bird species of high, median and low sensitivity

71



# Species sensitivity distribution

72 

### Dose (mg kg

- 1 

### bw ) Proportion of species affected

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1 10 100 1000

Log

- normal

model

Figure 6

## 8/21/2013

37 LD50 for 5 th 

### , 50 th


### and 95 th 

### centile species derived from SSD for flowable 

### chlorpyrifos

Average slope
then used to generate dose

response curves 

# SSDs used to derive acute dose



# response curves

73 0 25 50 75 100

0.01 0.1 1 10 100 1000 Mortality (%)

Dose ( mg kg

- 1 bw)

Sensitive Species (5th %ile)
Median Species (50th %ile)
Tolerant Species (95th %ile) Sensitive species (5 th centile)

Median species ( 50 th centile)

Tolerant species (95 th centile )

Figure 7 Mortality per application (%)

0

1 20 30 40 LiquidPARAM
TIM, V

- 1

Field

– no correction

Field

– correct for pre

appln mort.

Field

– corrected for pre

- appln

mort. & control mort.



### Corn (1.12 kg ha

- 1 

### , 1 lb A

- 1 

### ) Alfalfa (1.12 kg ha

- 1 

### , 1 lb A

- 1 

### ) 

# Comparison to TIM

- V1 and field data

for carbofuran

SI Figure 8

## 8/21/2013

38 

# Chronic effects metrics

► Insufficient data to derive an SSD or a dose

response curve

► Mallard reproduction (Fink, 1978 ) most useful study

► Number of eggs per hen most important factor causing reduced reproductive success

► NOEC = 25 mg ai/kg diet, LOEC = 125 mg ai/kg

diet



# ► Food intake rates of adult females reduced for first 28 d of study after which they recovered to rates in
control birds

75



# Chronic effects metrics (2)

► To convert dietary concentrations to doses for
adult females

► Calculated average food intake rate and body weight for females for first 28 d of study for each test concentration

► Multiplied effects concentration by normalized food

intake rate

► NOEL = 2.88 mg ai/kg bw/d, LOEL = 18.7 mg ai/kg bw/d



# ► Chronic exposure duration assumed to be 28 d in LiquidPARAM

76

## 8/21/2013

39 

# Acute risk results for flowable CPY

► Most species at low or de minimis risk

► However, intermediate or high risk observed in
scenarios that included:

► Highly sensitive species ( 5 th 

## centile )

► Insectivores that forage extensively in treated fields on foliage

- dwelling invertebrates



## ► Use patterns with large application rate

77

0 20 40 60 80 100

0 20 40 60 80 100 Species affected (%)

Mortality (%) 

# Example scenario for flowable CPY

in corn

Percentage of bird species affected versus percent mortality for flowable chlorpyrifos applied to corn (1.12 kg ha

- 1 

### or 1 lb A

- 1 

### ) broadcast at

- plant and band post

- plant 3X with a 10 d interval

. Figure 8 Risk High

- intermediate
Intermediate

- low
Low

- de minimis

## 8/21/2013

40 0 20 40 60 80 100

0 20 40 60 80 100 Species affected (%)

Mortality (%) 

# Example scenario for flowable CPY

in oranges

Percentage of bird species affected versus percent mortality for flowable chlorpyrifos applied airblast to oranges (6.28 kg ha

- 1 

### or 5.6 lb A

- 1 

### )

. Figure 9 Risk High

- intermediate
Intermediate

- low
Low

- de minimis



# Chronic risk results for flowable

CPY

► Could not categorize risk without dose

- response

curves

► For each bird species and use pattern,

calculated probabilities of exceeding NOEL and
LOEL

► Results indicated that chronic risk to birds is not a significant issue for flowable CPY

80

## 8/21/2013

41 0 20 40 60 80 100

American robin

Horned lark

Killdeer

Mourning dove Northern bobwhite

Red - winged blackbird Vesper sparrow Exceedence probability (%) Probability of Exceeding NOEL

Probability of Exceeding LOEL 

# Broadcast application on corn (1 lb. ai /A) + 2 banded applications with 10

- d intervals

81

0 20 40 60 80 100

Abert's towhee

Blue grosbeak

Common crow

Mourning dove

Red - winged blackbird Exceedence Probability (%) Probability of Exceeding NOEL

Probability of Exceeding LOEL 

# Air

- blast application on orange (5.6 lb

.

ai /A)

82 

### Small

exceedence 

### of the LOEL,

- de minimis

## 8/21/2013

42 

# Conclusions for flowable CPY

► Overall acute risk to bird community is generally

small

► Greater risk for sensitive species in fields with high application rates



# ► Chronic risk does not appear to be an issue

► Sensitivity analyses remain to be completed but likely 

## that avoidance behavior not a significant factor in reducing risk

83



# Overview

► Flowable chlorpyrifos

► Exposure scenarios and conceptual model

► Avian model to assess risks of flowable CPY ( LiquidPARAM )

► Methods and results



# ► Granular chlorpyrifos

► Exposure scenarios and conceptual model



## ► Avian model to assess risks of granular CPY ( GranPARAM )

► Methods and results



# ► Other lines of evidence

► Discussion

84

## 8/21/2013

43 

# Exposure Scenarios: Lorsban 15G

Crop Lorsban 15G Scenario Focal Bird Species

Broccoli California

- 2.25 lb./ A applied T

- band

at

- plant Horned lark, Red

- winged blackbird, Mourning dove

Corn and

sweet corn Corn belt

- 1.3 lb./ A applied T

- band at

plant Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite, Common pheasant

Corn belt

- 1.3 lb./A applied in

- furrow

at

- plant Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite, Common pheasant

Corn belt

- 1 lb./ A applied broadcast Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite, Common pheasant

Onion Pacific northwest

- 1 lb./ A applied in

furrow at

- plant Horned lark, Red

- winged blackbird, Mourning dove

85 Table 3



# Exposure Scenarios: Lorsban 15G (2)

Crop Lorsban 15G Scenario Focal Bird Species

Peanut Southeast

- 4 lb./ A applied band post

plant Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite

Sugar beet Midwest

- 1 lb./ A applied broadcast at

plant Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite, Common pheasant

Sunflower Midwest

- 1.3 lb./ A applied T

- band at

plant Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite, Common pheasant

Tobacco Southeast

- 2 lb./ A applied broadcast

preplant with incorporation Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite

Peanut Southeast

- 4 lb./ A applied band post

plant Horned lark, Red

- winged blackbird, Mourning dove, Northern bobwhite

86 Table 3

## 8/21/2013

44 Runoff/Erosion Application to agricultural fields

Effects Receptors Media Routes of transport Releases

Degradation to biologically inactive compounds

Uptake Direct deposition Leaching &

sub

- surface
flow 

# Conceptual model for granular CPY

Soil

Ingestion of particles

Birds

Reduced

survival

87 Figure 2



# GranPARAM

► Granular Pesticide Avian Risk Assessment Model

estimates pesticide granule intake for the day following application

► Birds ingest grit to aid digestion

► Can mistake pesticide granules for grit



## ► Exposure a function of

► Availability of natural grit in crop and region of interest

► Availability of pesticide granules on soil surface

► Rates of intake of particles

► Preferences of focal bird species



## ► Effects component same as for LiquidPARAM

► Determines fate of each of 20 birds on each of
1000 fields

► Chronic exposure not a concern because granules disappear rapidly from soil surface and only one granular application/season is permitted

on the label 88

## 8/21/2013

45 

# GranPARAM: Modifications for ERA



# of CPY

► Added soil series data for

broccoli in CA, onion in Pacific Northwest, sugar beet in Midwest, sunflower in Midwest,
and tobacco in Southeast

► Added foraging behavior component

► Added SSD approach

► Updated risk categorization component to use area under the curve concept to categorize
risk 89



# GranPARAM exposure

Proportion of
pesticide granules

Crop and region

Availability of
natural grit Species of interest

Particle
ingestion rate Gizzard grit

count Pesticide use scenario

Availability of
pesticide granules

Pesticide dose

Repeat for 20 birds

Repeat for 1000 fields

90 Figure 5

## 8/21/2013

46 Pesticide

dose

Alive Dead Yes No



### Repeat for 20 birds

Repeat for 1000 fields SSD approach Randomly select from

dose

- response curve No

Yes 

### Species

- specific

dose

- response curve ?

Exposure > Effects? Randomly select from

5 th 

### , 50 th 

### and 95 th 

### centile

dose

- response curves 

# GranPARAM effects

91 Figure 5



# Acute risk results for granular CPY

► Less than 1 % mortality for all use patterns and focal species

► Largely due to rarity of birds consuming pesticide 

# granules

► Built

- in conservatism for several input variables with

limited data did not trigger risks

► Assumed greatest, measured particle rate of ingestion for

all species of birds

► Bird species with softer diets or limited availability of natural grit will have lesser ingestions rates than assumed

in model

► Assumed no incorporation for broadcast applications

92

## 8/21/2013

47 

# Other lines of evidence

► Field studies have been conducted for granular
and flowable CPY

- very few mortalities associated

the treatments.



# ► Incident reports

– two reported since the change in labels in 2002. Caused by misuse.

93



# Field studies

- orchards

► Gallagher et al., 1994 ( flowable )

► Either applied 1.5 lb.ai/A Lorsban 4E post

- bloom and 6 lb.ai/A post petal fall or 3.5 lb.ai/A post

- bloom and 4 lb.ai/A post petal fall to citrus groves in CA

► Only 2 treatment

- related mortalities



## ► Selbach and Wilkens , 2008 (granular)

► Two applications of 2.1 lb.ai/A Dursban 75 WG (14

- d treatment interval) to 3 citrus groves in Spain (no control plots)

► Up to 6.5 mg ai /kg bw chlorpyrifos measured in 3 dead birds, but no

mortalities?



## ► Wilkens et al., 2008 (granular)

► Three applications of 0.86 lb.ai/A Dursban 75 WG to 1 apple orchard (14

- and 28

- d intervals) and 2 applications to 2 orchards (14

- d intervals) (no control plots)

► No treatment

- related mortalities

94

## 8/21/2013

48 ► Wolf et al., 2010 (granular)

► Pome fruit



### • 2 applications (14

- d interval) of 0.86 lb.ai/A Dursban 75 WG

• 3 applications (14

- d and 28

- d intervals) of 0.86 lb.ai/A Dursban 75
WG

► Citrus fruit

• 2 applications (14

- d interval) of 2.1 lb.ai/A Dursban 75 WG

► Ten carcasses recovered in total, but no deaths attributable to
treatment of fields

► State of the art study 

# Field studies

– orchards (2)

95



## ► Frey et al., 1994 ( flowable and granular)

► Lorsban 4E applied at 3 lb.ai/A pre

- plant and 1.5 lb.ai/A at

- plant, whorl and tassel stages to corn crops in Iowa

► 20 bird carcasses recovered; 1 may have been treatment

- related



### ► Lorsban 15G applied at 2.6 lb.ai/A at

- plant and at 0.975 lb.ai/A at the whorl and tassel stages to corn crops in Iowa

► 14 bird mortalities, none due to treatment



## ► Brown et al., 2007 ( flowable )

► Dursban 480 EC applied twice with a 14

- d application interval and
rate of 0.32 lb.ai/A to 8 vineyard plots in southern France (no control plots)

► 4 avian mortalities; residues consistent with dermal exposure (0.27 to 1.3 mg ai /kg

- bw ), but not cause of death 

# Field studies

– row crops

96

## 8/21/2013

49 

## ► Moosmayer and Wilkens , 2008 (flowable)

► Dursban 480 EC applied twice with an application interval of 14 d and application rate of 0.86 lb.ai/A to 3 cabbage fields in Poland

► No signs of toxicity or avian mortalities were observed



## ► Wolf et al., 2010 ( flowable )

► Applied Dursban 480 EC (2 applications; 14

- d) at 0.86 lb.ai/A to brassica crops

► No mortalities in this state of the art study 

# Field studies

– row crops (2)

97



# Field studies

– field crops (3)

► Worley et al., 1994 ( flowable and granular)

► Dursban turf (liquid) and Dursban 2.5G (granular) applied twice to turf on golf courses in FL at 4 lb...... ai /A and interval of 21 d

► 4 bird carcasses were recovered following liquid applications and 2 following granular application. Cause of death could not be

determined



## ► Clements et al., 1992 (granular)

► Spannit applied to two permanent pastures at a rate of 0.64 lb......

ai /A

► Brent and Canada geese were observed feeding on the pastures before and after applications. No treatment

- related mortalities

occurred

98

## 8/21/2013

50 

# The bottom line

► Flowable CPY

► According to model results, some acute risk issues for sensitive bird species in higher rate use patterns

► Most bird species, however, not at significant acute risk for assessed use patterns



## ► Field results and lack of incident reports suggests that selection of surrogate focal species in LiquidPARAM
results in an overestimation of acute risk

► Chronic risk not a significant issue



# ► Granular CPY

► According to model results, de minimis risk for birds

► Field results and incident reports consistent with
results of model

99



# Exposures of aquatic organisms resulting from the use of chlorpyrifos in North America

RA 5

100

## 8/21/2013

51 

# Introduction

► Substantial monitoring of CPY in aquatic systems
has been conducted.

► These data are invaluable in characterizing the range of environmental concentrations in aquatic

water bodies.

► However, relatively few monitoring programs have 

# sufficient frequency to quantify time

- series patterns of exposure which is necessary for understanding

the duration and frequency of exposure to CPY

. ► An argument has been made by some that the existing monitoring data misses short

- term pulses
that could cause adverse effects

101



# Measured values CPY (surface waters)

102 Region 95 th centiles of measured concentrations (μg L

- 1 )

Agricultural Mixed Undeveloped Urban All classes

All FRRs 0.0097 0.006 0.008 0.0067 0.007

Heartland 0.018 0.005 N/A a 0.0076 0.007

Northern Crescent N/A 0.005 0.005 0.005 0.005

Northern Great Plains N/A 0.005 0.005 N/A 0.005

Prairie Gateway N/A 0.005 0.009 0.008 0.0067

Eastern Uplands N/A 0.005 v 10.0 0.005

Southern Seaboard 0.005 0.006 N/A 0.005 0.005

Fruitful Rim 0.0086 0.022 0.005 0.0098 0.015

Basin and Range 0.005 0.005 0.01 0.005 0.009

Mississippi Portal 0.0065 0.006 0.005 0.012 0.007

Table 4

## 8/21/2013

52 0 0.01 0.02 0.03 0.04 0.05 0.06

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010


### Year 95 th centile of c oncentration ( μ g L - 1 )



### Detections

95 th 

### centiles

0

10 20 30 40 50 60 Detections (% of samples) 

# Detections and 95 th 

# centiles of CPY

in surface water

Figure 3



# Measured values CPYO (surface waters)

104 

### Database Measured concentrations (μg L

- 1 

### )

Dates No. analyses Detected Range

NAWQA 1999

- 2012 7,098 16 0.011 to 0.054 a



### NASQAN 2001

- 2012 2025 9 0.011 to 0.036 a



### CA

- SWD 2005

- 2010 288 0 N/A



### WA

- EIM 2009

- 2011 964 0 N/A

a 

### All less the LOD, estimated values provided

## 8/21/2013

53 

# Objective of modeling

► Modeling can be used to predict exposures in the absence of monitoring or extrapolate from monitoring data to answer questions relative to
maximum likelihood

► To model representative environments of greater

exposure across the United States

► To characterize time

- series concentrations of 

# chlorpyrifos in water and sediment

► To address return frequencies and the probability of missing short

- term exposures that might be sufficiently great to cause adverse effects

105



# Assessment overview

Conceptual model • Wide variety of use patterns with respect to geography, crops,

labels, and application methods

• Chemical properties

- see above

• Transport pathways

- runoff, erosion, spray drift, volatilization



### Scenario selection • Geographical focus areas

- parallel examination of use density and

a sensitivity analysis of soil

- weather

- crop

- label combinations

• One high exposure watershed (3rd order stream) selected from each focus area that had a density of eligible crop



### Model simulations • Dry Creek, Miller County, GA

– PCA=48%

• Cedar Creek, Leelanau peninsula, MI

– PCA=23%

• Orestimba Creek, Stanislaus County, CA

– PCA=19%

106

## 8/21/2013

54 

# Conceptual model

– use of CPY

► Granular and flowable formulations to foliage, soil,

and dormant trees

► Using aerial equipment, chemigation systems, ground boom sprayers, air

- blast sprayers, tractor

drawn spreaders, and handheld equipment

► Pre

- plant, at plant, post

- plant, or dormant season

107



# Conceptual model: use of CPY

► Major crop uses (2007 data)

0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000 1,600,000 1,800,000 2,000,000



### More than half of use is

in soybeans and corn

108

## 8/21/2013

55 

# Conceptual model: Physical properties

Parameter Values for Chlorpyrifos Source

Chemical Name O,O

- diethyl O

- (3,5,6

- trichloro

- 2

- pyridyl phosphorothioate USEPA, 2011

Chemical Abstracts Service (CAS) Registry Number 2921

- 88

- 2 USEPA, 2011

Empirical Formula C 9 

### H 11 

### Cl 3 

### NO 3 

### PS USEPA, 2011



### USEPA Pesticide Code (PC #) 59101 USEPA, 2011

Molecular Mass 350.6 g/ mol Mackay, 2013

Vapor Pressure (25 ° C) 1.73x10

- 5 

### torr Mackay, 2013

Water Solubility (20 ° C) 0.73 mg/L Mackay, 2013

Henry‟s Law Constant 1.10 x 10

- 5 

### atm

- m 3 

### / mol Mackay, 2013



### Log Kow 5.0 Mackay, 2013

109 Table 1



# Conceptual model: Chemical properties

Parameter Values / Source Source

Aqueous hydrolysis (t1⁄2) pH 5: 73 d pH 7: 72 and 81 d pH 9: 16 d USEPA, 2011

Aqueous photolysis (t1⁄2) 29.6 days USEPA, 2011

Aerobic soil metabolism (t1⁄2) 1.9

- 1576 days See Table A

- 1

Aerobic aquatic metabolism (t1⁄2) 22

- 51 days See Table A

- 5

Anaerobic soil metabolism (t1⁄2) 15 and 58 days USEPA, 2011



### Anaerobic aquatic metabolism (t1⁄2) 39 and 51 days USEPA, 2011

Soil adsorption coefficient K OC 

### 973

- 31000 mL/g See Table A

- 4

Terrestrial field dissipation (t1⁄2) 1.3

- 120 days See Table A

- 3

110 Table 2

## 8/21/2013

56 

# Selection of focus areas

Density of product Use Relative runoff/erosion potential

111 Figures 1, 5, 6, 7



# Counties associated with standard

watershed scenarios

112 Figure 7

## 8/21/2013

57 

# Sensitivity analysis

► USEPA standard pond with PRZM

- EXAMS models

► A pplications CPY reflect maximum label rates, minimum application intervals

► Used reports and extension documents provide additional guidance with respect to timing of applications

► Two sets of simulations

► Simulation 1 = 28

- d aerobic soil half

- life ( Caitlin IL)

► Simulation 2 = 96

- d aerobic soil half

- life ( Stockton CA)



## ► Chemical properties consistent with USEPA guidance except for:

► Foliar degradation rate 3.28 d derived from measured values



### ► PRZM input files were modified to incorporate loss by

volatilization

113

0 5 10 15 20 25

90 th centile of estimated 96 - h TWMC (μg L - 1 )

Scenario 28

- d aerobic soil half

- life)

96

- d aerobic soil half

- life)

Figure 7 

# Half

- life and predicted concentration

## 8/21/2013

58 

# Properties used in simulations of fate in

the environment

Property Value Used in Model Simulations

Molecular weight 350.6 g mol

- 1 Water solubility (20 ° C) 0.73 g mol

- 1 Vapor pressure (25 ° C) 1.87x10

- 5 torr Henry‟s law constant (20 ° C) 5x10

- 6 (dimensionless)

Soil adsorption / desorption, Koc 8216 cc g - 1 (mean Koc from 37 data points)

Aerobic soil metabolism (t1⁄2) Run 1: 28.2 days ( Catlin, IL) Run 2: 96.3 days ( Stockton CA)
Anaerobic soil metabolism (t1⁄2) 103 d

Aqueous hydrolysis (t1⁄2) pH 5: 73 d pH 7: 81 d pH 9: 16 d Aqueous photolysis (t1⁄2) 29.6 d
Aerobic aquatic metabolism (t1⁄2) 50.8 d

Anaerobic aquatic metabolism (t1⁄2) 63 d Foliar degradation (t1⁄2) 3.28 d Foliar washoff (/cm) 0.1 Plant uptake 0.0

115 Table 5



# Applications simulated in sensitivity analysis

Scenario Application

rate (kg a.i./ha) No.

Apps Interval(s)

(d) Date of first application Application

method CAM Incorporation depth (cm) Application

efficiency Spray drift

fraction

NYgrape1 1 2.4 1

- 15

- Jun Drench 1 0 0.99 0.01

NYgrape2 1 2.4 1

- 15

- May Drench 1 0 0.99 0.01

NYgrape3 1 1.2 1

- 15

- Jun Drench 1 0 0.99 0.01

NYgrape4 1 1.2 1

- 15

- May Drench 1 0 0.99 0.01

CAgrape1 2 2.1 1

- 28

- Feb Drench 1 0 0.99 0.01

CAgrape2 2 1.1 2 195 28

- Feb Drench 1 0 0.99 0.01

PAturf 3 2.1, 4.2, 4.2,

1.1, 1.1, 1.1, 1.1 7 30, 30, 30, 60, 30, 30 14

- Mar Foliar 2 0 0.99 0.01

GApecan1 4 4.2, 2.1, 2.1 3 10 15

- Jun 1 Foliar, 2
orchard floor 2 & 1 0 0.95 & 0.99 0.039 & 0.01

GApecan2 5 1.0 3 10 15

- Jun Foliar 2 0 0.95 0.039

GApecan3 5 1.4 3 10 15

- Jun Foliar 2 0 0.95 0.039

FLcitrus1 4 3.7, 3.7, 1.1,

1.1, 1.1 5 30, 10, 10,

10 10

- Aug 2 Foliar, 3 to

orchard floor 2 & 1 0 0.95 & 0.99 0.039 & 0.01

FLcitrus2 4 3.7 1

- 10

- Aug Foliar 2 0 0.95 0.039

FLcitrus3 4 3.7 2 10 10

- Aug Foliar 2 0 0.95 0.039

CAcitrus1 4 3.9, 3.9, 1.1,

1.1, 1.1 5 30, 10, 10,

10 10

- Aug 2 Foliar, 3 to

orchard floor 2 & 1 0 0.95 & 0.99 0.039 & 0.01

CAcitrus2 4 6.3 1

- 10

- Aug Foliar 2 0 0.95 0.039

CAcitrus3 4 3.9 2 10 10

- Aug Foliar 2 0 0.95 0.039

MIcherries1 4 3.16 3 14, 60 15

- May Trunk spray/lower

branches 2 0 0.99 0.01

116 Table 6

## 8/21/2013

59 Applications simulated in sensitivity analysis( cont )

Scenario Application

rate (kg a.i./ha) No.

Apps Interval(s)

(d) Date of first application Application

method CAM Incorporatio

n depth (cm) Application

efficiency Spray drift

fraction

MIcherries 24 1.7 2 10 15

- May Foliar 2 0 0.99 0.01

ILcorn1 6 1.5 1

- 15

- Apr T

- Band 7 4 1 0.1

ILcorn2 6 1.5, 1.1 2 60 15

- Apr T

- Band,
Broadcast 7 & 2 4 & 0 1 & 0.95 0.1 & 0.039

ILcorn3 6 1.1 3 10 15

- Apr Broadcast 2 0 0.95 0.039

INcorn1 6 1.5 1

- 1

- May T

- Band 7 4 1 0.1

INcorn2 6 1.5, 1.1 2 60 1

- May T

- Band,
Broadcast 7 & 2 4 & 0 1 & 0.95 0.1 & 0.039

INcorn3 6 1.1 3 10 1

- May Broadcast 2 0 0.95 0.039

NCcornE1 6 1.5 1

- 1

- Apr T

- Band 7 4 1 0.1

NCcornE2 6 1.5, 1.1 2 60 1

- Apr T

- Band,
Broadcast 7 & 2 4 & 0 1 & 0.95 0.1 & 0.039

NCcornE3 6 1.1 3 10 1

- Apr Broadcast 2 0 0.95 0.039

NCcornW1 6 1.5 1

- 10

- Apr T

- Band 7 4 1 0.1

NCcornW2 6 1.5, 1.1 2 60 10

- Apr T

- Band,
Broadcast 7 & 2 4 & 0 1 & 0.95 0.1 & 0.039

NCcornW3 6 1.1 3 10 10

- Apr Broadcast 2 0 0.95 0.039

NEcorn1 6 1.5 1

- 10

- May T

- Band 7 4 1 0.1

NEcorn2 6 1.5, 1.1 2 60 10

- May T

- Band,
Broadcast 7 & 2 4 & 0 1 & 0.95 0.1 & 0.039

NEcorn3 6 1.1 3 10 10

- May Broadcast 2 0 0.95 0.039

117 Table 6



# Watershed scenarios (Georgia and Michigan)

► PRZM

- SWAT models ( winPRZM for California)

► HUC

- 14 characterization

► Three stream orders

► 90 th 

### centile crop density



### ► Use of CPY

► Crop/application schedule resulting in highest exposure predictions from sensitivity analysis

► One week application window



### ► Channel properties from NHD

► Drift

► Assume % of streams receiving drift = % of crop in watershed

► 1.9% drift for aerial applications ( AgDRIFT with 150‟ setback and medium



### coarse droplet)

► 0.3% drift for ground applications ( AgDRIFT with 25‟ setback and fine

- medium droplet)

► Drift rate = Application rate * total stream surface area * drift factor * PCA

118

## 8/21/2013

60 

# Land use distribution of Dry Creek watershed, Georgia

48% non

- pasture crop

• Cotton 21%

• Peanuts 17%

• Corn 5%

• Pecans 0.6
Simulations reflected 100% of pecans treated

119 Figure 10



# Land use distribution of Cedar Creek 

# watershed, Michigan

23% non

- pasture crop

• Orchard 12%

• Alfalfa 4.4%

• Corn 3%
Simulations reflected 100% of

cherries treated

120 Figure 11

## 8/21/2013

61 

# Watershed scenario (California)

► California is unique

► Furrow and flood irrigation ( winPRZM

- SWAT models)

► CPY use is known from PUR database

– actual use and timing

► 8

- year simulation



# ► California

- specific runoff

- erosion assessment

► CoPST modeling framework

121



# Watershed scenario

- California

► California unique

► Furrow and flood irrigation ( winPRZM

- SWAT models)

► CPY use is known from PUR

database



## ► California

- specific runoff

erosion assessment

► Sacramento River, San Joaquin River, and Bay

- Delta watersheds

► CoPST modeling framework

► 8

- year simulation

Orestimba Creek watershed (SWAT model courtesy of UCD) Estimated average annual chlorpyrifos loss

122 Figure 9

## 8/21/2013

62 

# Land use distribution of Orestimba Creek watershed, California

18% non

- pasture crop

• Almond 6%

• Alfalfa 4.4%

• Double crop oats/corn 3%

• Corn 2%

• Oats 1.4%

• Tomatoes 1.4%

• Walnuts 1.0%
Simulations based on actual use
of CPY

123 Figure 12



# Spray drift

X acres were

treated

but where in the square mile grid?

Conservatively

assumed all 

### acreage near water
treated. (Unit of Analysis

– PLSS Section)



### What were the application conditions, wind, temperature, etc ?

124

## 8/21/2013

63 

# Spray drift

125



# Estimated 96

- h time

- weighted mean
concentrations of CPY in focus watersheds

126 Table 8 

### Location

of

watershed Concentration in 

### water (μg L

- 1 

### ) Concentration in 

### sediment (μg kg

- 1 

### )

28

- d DT50 96

- d DT50 28

- d DT50 96

- d DT50

California Minimum 0.003 0.013 4.74 10.8

Median 0.024 0.251 7.91 14.6

90 th 

### centile a 

### 1.319 1.543 10.8 20.8

Maximum 1.392 2.142 11.0 22.2

Georgia Minimum 0.004 0.004 0.007 0.007

Median 0.010 0.010 0.023 0.027

90 th 

### centile 0.020 0.020 0.050 0.060

Maximum 0.023 0.023 0.064 0.067

Michigan Minimum 0.002 0.007 0.027 0.010

Median 0.011 0.018 0.021 0.038

90 th 

### centile 0.018 0.034 0.032 0.060

Maximum 0.028 0.043 0.047 0.074

a Values reflect the 90 th centile of the annual maxima (1 in 10 y maximum value)

## 8/21/2013

64 

# Event duration analysis in focus

watersheds

127 Location of watershed Duration of events for 28

- d half

- life

Georgia Michigan California

Event threshold μg L

- 1 0.1 1.0 0.1 1.0 0.1 1.0

No. of events 0 0 0 0 10 4

Min. duration (d) n/a n/a n/a n/a 1 1

Max. duration (d) n/a n/a n/a n/a 11 2

Median duration (d) n/a n/a n/a n/a 1 1.5

Avg. duration (d) n/a n/a n/a n/a 2.9 1.5

Duration of events for 96

- d half

- life

No. of events 0 0 0 3 35 10

Min. duration (d) n/a n/a n/a 1 1 1

Max. duration (d) n/a n/a n/a 1 15 6

Median duration (d) n/a n/a n/a 1 1 1

Avg. duration (d) n/a n/a n/a 1 2.3 1.9

Table 9



# Uncertainty

► Uncertainty is inherent in any modeling study due to incomplete knowledge, simplifications in representing natural systems, and strength of various underlying databases

► Verification of model results was limited for this study

► Several field

- specific runoff studies were simulated ( Cryer , 1995; McCall, 1984; Poletika, 1994; Racke , 1993)

► Predicted runoff water volume, sediment yield, and chlorpyrifos runoff in water and in eroded sediment, were approximately 10

- times ( ± ) of

the measured values without calibration.

► Estimated environmental concentrations in water in the three 

### watersheds were in general agreement with ambient monitoring data
collected from 2002

- 2010

.

128

## 8/21/2013

65 

# Uncertainty (2)

► The characterization of chlorpyrifos in the

environment could be enhanced

► Addition of a fourth watershed centered around PA corn

or NE claypan

. ► Additional reality in the simulated three watershed (e.g., heterogeneity in cropping and soils in Georgia and Michigan; management plans being introduced into
Orestimba Creek, weather

- specific drift estimates and proximity of fields to water in all three watersheds ).

129



# The bottom line

► Frequency of detection and concentrations of CPY in
surface waters across the US have declined since (before) 2002.

► Concentrations of CPYO consistently below the LOD,
even in areas of intensive use.

► Concentrations in water from Tier

- 3 modeling in GA, MI,
and CA were similar to the values measured between

2000

- 2010.

► Median durations above 0.1 μ g/L were ≤ 2 d.

► Paucity of measured values from sediment, only

modeled values available.

130

## 8/21/2013

66 

# Risks to aquatic organisms from the use of chlorpyrifos in North

America

RA 6

131



### Sources

Run

- off, leaching, erosion, tail waters

Upstream

sources ( streams)

Spills

Groundwater Direct application Drift and atmospheric deposition 

### Wildlife receptors

Wildlife that
eat fish/other

vertebrates Wildlife that

eat
invertebrates and plants Exposures (food chain) 

### Aquatic receptors

Fish Aquatic and
benthic
invertebrates

Amphibians/ reptiles/

mammals Aquatic macrophytes Aquatic algae/

microbiota Exposures

Bioturbation , Binding Phases and

Hydrodynamic Factors 

### Aquatic repositories

Burial, Resuspension ,

Sorption and Desorption

Deep
sediment Surface

sediment Surface

water &
wetlands Exposures 

# Conceptual model for exposures

Bioconcentration but no biomagnification

132 Figure 1

## 8/21/2013

67 Wildlife receptors

Wildlife that
eat fish/other

vertebrates 

### Aquatic receptors

Fish Aquatic and
benthic
invertebrates

Amphibians/ reptiles/

mammals Aquatic macrophytes Aquatic algae/

microbiota 

### Sources of

exposure

Deep
sediment Surface

sediment Surface water

& wetlands



### Direct
Indirect Wildlife that

eat aquatic plants

Wildlife that

eat aquatic
invertebrates Direct effects resulting from exposures Indirect effects resulting from direct effects 

# Conceptual models of effects

133 Figure 2

N C l C l C l

O P S O C H 2 C H 3

O C H 2 C H 3 Chlorpyrifos Chlorpyrifos

- oxon [O]



### AChE OH k 1

k 3 k 2 Phosphorylation



### AChE O P O O C H 2 C H 3

O C H 2 C H 3



### AChE OH

Hydrolysis and

reactivation N C l C l C l

O P O O C H 2 C H 3

O C H 2 C H 3



### AChE O P O O H

O C H 2 C H 3 k

- 1

Aging (hydrolysis) Aged enzyme cannot
be reactivated

Recovered enzyme
returns to normal
function

N C l C l C l

O H

TCP 

### + 

# Mechanism of action

- recovery

134

## 8/21/2013

68 

# Recovery

– addressing k 3 Exposure and response



## Time

Response to

exposure 1 

### Response to exposure 2

135



# Recovery Exposure and response



## Time Response to

exposure 1 Response to exposure 2 partially additive to exposure 1

136

## 8/21/2013

69 

# Recovery

Taxon Recovery time

Crustacea and insects 1

- 7 d

Fish 4

- 8 wks

137 

# ► Hydraulics of flowing water

– pulsed exposures.

► Reciprocal relationship between time of exposure and effects.

► Recovery of AChE via k 3 

## ► Synthesis of new AChE



# ► Data for invertebrates and fish

► Aquatic organisms can also recover via propagules

, metapopulations , and/or migration

DOW CONFIDENTIAL

- Do not share

without permission



# Selection of toxicity data

Strength of

methods 1 2 3 4 5

Description of

the experimental and procedures Inadequately

described or

incorrect Critical

information on

methods missing Critical

information on

methods and procedures provided Procedures

described so that the study

could be replicated or spirit of GLP Guideline study

or complete

detailed protocol or full
GLP

QA/QC None Some QC (e.g.,

exposures measured once) More QC (e.g.,

exposures measured on a regular basis) Robust QA/QC Full QA/QC

Transparency
of data Critical data not

provided Summary data

only Summary data

with variance

character-ized Key raw data

provided All raw data

provided

Concen-trat-ion

s tested Only 1 conc.

tested 2 concs . tested 3 concs . Tested or field study >

3 sites 4 concs . tested ≥ 5 concs

. tested

Descriptors
from Klimisch

et al. 1997 Not assignable Not reliable With restriction Without restrictions

Klimisch H

- J, Andreae M, Tillmann U. 1997. A systematic approach for evaluating the quality of experimental toxicological and ecotoxicological data. Regulatory Toxicology and Pharmacology

25:1

- 5.

138 Table 1

## 8/21/2013

70 

# Toxicity data

- duration

► Previous review (Giesy et al. 1999) used 2

- d toxicity data.

► Current review used standard 48 to 96

- h LC50 tests as a conservative measure of sensitivity.

► Other responses, such as behavioral not

included

– unable to link to the apical responses.

► Chronic toxicity not included

– all exposures are short and chronic exposures assessed in cosms.



# ► Data characterized as Species Sensitivity Distributions (SSDs) using SSD

- Master Ver 2 (2007).

139



# Toxicity data

- algae

► Not expected to be very sensitive.

► There were 6 species of plants tested, one
met the criteria for inclusion.

► Range of EC50s for algae was from 138 to 2000 μg L

- 1



# ► Not considered further.

140

## 8/21/2013

71 Crustaceans

Insects Fish

0.0 0.2 0.4 0.6 0.8 1.0

0.001 0.1 10 1000 100000 10000000 1E+09 1E+11 Proportion of taxa affected

Concentration (ng L

- 1) Normal Logistic Gompertz
Weibull
Fisher

- Tippett

0.0 0.2 0.4 0.6 0.8 1.0

0.001 0.1 10 1000 100000 10000000 Proportion of taxa affected

Concentration (ng L

- 1 ) Normal
Logistic
Gompertz

Weibull

Fisher

- Tippett

0.0 0.2 0.4 0.6 0.8 1.0

0.001 0.1 10 1000 100000 10000000 1E+09 Proportion of taxa affected

Concentration (ng L

- 1 ) Normal Logistic Gompertz
Weibull
Fisher

- Tippett

SI Figure 1



# Toxicity data

– crustaceans (23)

142 

### Concentration of chlorpyrifos (μg L

- 1 

### ) 10

- 3 10

- 2 10

- 1 10 0 10 1 10 2 10 3 10 4 Proportion of crustacean species

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Simocephalus vetulus Daphnia magna

Gammarus palustris

Procambarus sp Amphiascus tenuiremis Gammarus fossarum Orconectes immunis Asellus aquaticus Eriocheir sinensis

Neocaridina denticulata

Daphnia ambigua Ceriodaphnia dubia Hyalella azteca Moina australiensis Gammarus lacustris Paratya australiensis

Palaemonetes pugio Neomysis integer

Daphnia pulex Daphnia carinata Daphnia longispina

Gammarus pulex Macrobrachium rosenbergii

5 th centile = 0.038 μg L

- 1 L 95%CI

U 95%CI

Figure 1

## 8/21/2013

72 

# Toxicity data

- crustaceans

► Twenty

- three studies met the criteria for

inclusion.

► Range of LC50s was 0.035 to 457 μg
CPY L

- 1



# ► HC5 (95%CI) was 0.038 (0.024

- 0.062) μg
CPY L

- 1



# .

143



# Toxicity data

– insects (18)

144



### Concentration of chlorpyrifos (μg L

- 1 

### ) 10

- 3 10

- 2 10

- 1 10 0 10 1 10 2 10 3 10 4 Proportion of insect species

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Deleatidium sp. 5 th centile = 0.091 μg L

- 1 Notonecta maculata

Chironomus riparius Atalophlebia australis Simulium vittatum Chaoborus obscuripes

Chironomus dilutus Anax imperator Plea minutissima Corixa punctata Sigara arguta

Cloeon dipterum

Ranatra linearis Xanthocnemis zealandica Paraponyx stratiotata L 95%CI

U 95%CI

Figure 4

## 8/21/2013

73 

# Toxicity data

- insects

► Eighteen studies met the criteria for

inclusion.

► Range of LC50s was 0.05 to >300 μg CPY L

- 1



# ► HC5 (95%CI) was 0.091 (0.024

- 0.062 ) μg
CPY L

- 1



# .

145



# Toxicity data

– fish (25)

146



### Concentration of chlorpyrifos (μg L

- 1 

### ) 10

- 3 10

- 2 10

- 1 10 0 10 1 10 2 10 3 10 4 Proportion of fish species

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Menidia menidia Menidia peninsulae Leuresthes tenuis Lepomis macrochirus Fundulus heteroclitus Pungitius pungitius

Atherinops affinis Menidia beryllina Poecilia reticulata Cyprinus carpio Oncorhynchus mykiss Gasterosteus aculeatus Oncorhynchus clarki Sander vitreus Melanotaenia fluviatilis Salvelinus namaycush Pimephales promelas Oryzias latipes Gambusia affinis Opsanus beta

5 th centile = 0.820 μg L

- 1 Aphanius iberus Rutilus rutilus L 95%CI

U 95%CI

Leuciscus idus

Figure 5

## 8/21/2013

74 

# Toxicity data

- fish

► Twenty

- five studies met the criteria for

inclusion.

► Range of LC50s was 0.53 to 806 μg CPY

L

- 1



# ► HC5 (95%CI) was 0.820 (0.494

- 1.360) μg
CPY L

- 1



# .

147



# Other groups

► Amphibians

► Three studies met the criteria for inclusion and one was questionable.

► Range of LC50s was 14 to a questionable value of 5,174 μg CPY L

- 1



# . ► Not included in the ERA

– fish are protective.



# ► Other invertebrates

► Rotifers, mollusks, worms.

► All EC50s > 287 μg CPY L

- 1 

# , not included in

ERA

148

## 8/21/2013

75 

# Toxicity to benthos

LC50 of CPY
Species μg CPY Kg

- 1 

# ( dw ) ng g - 1 

# OC

H. azteca (10 d) 399 2,122

C. dilutus (10 d) 399 4,815

149 

# ► Concentration in pore water close to water

- only
LC50.

► Risk extrapolated from the water

- column organisms as in Giesy at al. (1999).

Table 3



# Toxicity CPYO

LC50 ( μ g L

- 1 

# )
Species CPY CPYO

D. magna (48 h) 0.82 1.9

L. macrochirus (96 h) 4.2 1.1

150 

# ► One value for Rana boylii > 5 μ g L

- 1 

# from a study that did not meet the criteria for inclusion.

► ERA for CPYO strongly correlated to parent.

► Formed in vivo and in the environment.

► Implicitly included in toxicity testing, more polar, more

reactive in water.



# ► Not found in surface waters above LOD, separate ERA not needed.

Table 4

## 8/21/2013

76 151



# ► Since the 1999 review of CPY

, ► Four new studies have been published

. ► Also, the 1993 Springborn study has been reanalyzed using Principal Response Curves.



# ► Almost without exception, all of the cosm studies have demonstrated an ecosystem

- level No
Observed Adverse Effect Concentration ( NOAEC

eco 

# ) of 0.1 μg/L

. ► Responses of populations to chlorpyrifos in cosms very consistent with laboratory tests.

► Crustaceans > insects > fish > rotifers



# Effects in cosms

152

## 8/21/2013

77 

# Risks from measured exposures

153 

### Concentration of chlorpyrifos ( μ g L

- 1 

### ) 10

- 3 10

- 2 10

- 1 10 0 10 1 10 2 10 3 10 4 Proportion of species

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

USGS, 0.056 pre - 2001 USGS, 0.008 post - 2001 USGS

– max 95 th

centiles from

measured
concentrations

Cosm NOAEC eco

Figure 6



# Risks from modeled exposures (CA)

154 

### Percent of species with exceedences of 96

- h LC50s 0 20 40 60 80 100 Percent exceedences of 96 - h LC50s,

Orestimba Creek, CA

0 20 40 60 80 100

Fish

Crustacea

Insects

Figure 7

## 8/21/2013

78 

# Risks from modeled exposures (MI)

155 

### Percent of species with exceedences of 96

- h LC50s 0 20 40 60 80 100 Percent exceedences of 96 - h LC50s, Cedar Creek, MI

0 20 40 60 80 100

Fish

Crustacea

Insects

Figure 8



# Risks for benthos modeled

exposures

► None of the maximum modeled 

# concentrations exceed the toxicity value
for sediments

156 

## μg CPY Kg

- 1


## Species LC50 GA MI CA

H. azteca (10 d) 399 0.08 0.09 22.8

C. dilutus (10 d) 399

## 8/21/2013

79 

# RADAR

Time Threshold (HC5) Peak Height Duration

Date 

## Data

Date Concentration

Recovery time

157



# Radar analysis of pulsed exposures

Taxon Threshold

Conc. ( μ g L

- 1 

### ) Duration

(h) Recovery

period (d)

Crustacea > 0.038 = 96 ≤ 14

Insects > 0.091 = 96 ≤ 14

Fish > 0.802 = 96 ≤ 56

158 

### Taxon Number of peaks exceeding all 3 thresholds

Georgia

1961

- 1990 Michigan

1961

- 1990 California OC

2000

- 2009

Crustacea 0 0 4

Insects 0 0 3

Fish 0 0 2 Table 6

Table 7

## 8/21/2013

80 

# The bottom line

► Risks from CPY across the USGS monitoring sites have

declined since 2000

► Risks from CPYO in surface waters are de minimis.

► For CPY, the HC5 concentrations and the NOAECs for

the cosms were similar to the previous assessment.

► De minimis risks to benthos from CPY.

► More data were available to characterize recovery from
inhibition of AChE

. ► Pulsed exposures not at in issue in GA and MI but a potential issue in Orestimba Creek in CA.

► Few incidents reported and all were related to misuse, misapplication, or deliberate dumping.

159



# Risk to pollinators from the use of chlorpyrifos in North America

RA 7

160

## 8/21/2013

81 

# Importance of pollinators

► More than 3⁄4 of angiosperms rely on animals for pollination

► Ca. 75% of global fruit, vegetable and seed crops depend on animal pollination to some extent

► Keystone species  Pollination lays a groundwork for essential ecosystem services

► Seed development  continued evolution and
maintenance of floral biodiversity



# ► Declines in populations of pollinator are of

concern

► Reports of insecticides, including CPY causing effects on pollinators

161



# Bee pollinators

► Bees by far the most important animal pollinators

► Agricultural pollination relies on wild and managed bees

► European honey bee, Apis mellifera

► The workhorse

► Generalist pollinator found worldwide

► Worth ~ $15 billion to agriculture in the

United States

► Critically important for almonds, apples and other tree fruits, blueberries and other berries, alfalfa seed, melons, sunflowers, etc. 162

## 8/21/2013

82 

# Honey bee biology and RA

► Considerations for risk assessment

► „ Superorganism ‟

– colony growth and survival depends on the collective actions of different castes

► Different castes of bees have different functions, which can result in differential exposure in terms of duration, magnitude, and mode

► Colonies typically have a 10

- 30% reserve of workers

► Reflects and accommodates high turnover rate

► Survival of an individual bee may be of little consequence



# ► Large forage area of honey bees complicates the task of estimating and avoiding potential exposure

163



# Bee pollinators

► Bumble bees ( Bombus spp .)

► A smaller „super

- organism‟

► Maintenance of natural floral diversity and agricultural pollination

► Ground nesters (e.g. rodent holes) but also commercially produced

► Recently utilized as vectors of biopesticides

164

## 8/21/2013

83 

# Bee Pollinators

► Leafcutter and mason bees

► E.g

., Megachile rotundata

, Osmia lignaria



# ► Wild but also accept trap

nests and so are easily managed and produced



# ► Alfalfa leafcutter bee can be deployed in great numbers
 alternative to honeybees

on some crops

165



# Biology of solitary bees and ERA

► Most non

- Apis bees are significantly smaller than honey bees  relatively higher dose

► Eggs mostly laid directly on raw pollen and nectar
 often greater concentrations of pesticide

► Forage over smaller area  less „dilution ‟ of pesticide

► Individuals in the field are relatively more important

► Different nest materials (e.g

., mud,
leaf pieces) and sites (e.g

., ground

, stems )

166

## 8/21/2013

84 

# Other pollinators

► “Pollinator” = any vector that moves pollen from the male anthers of a flower to the female stigma of a flower

- excluded

167



# The p roblem

► Chlorpyrifos is toxic to insect pollinators

► Agroecosystem in which chlorpyrifos is used

contains managed and wild pollinators

► Almonds , citrus fruits, berries; pollinators are key

► E.g

., corn

• Potentially large inputs of chlorpyrifos

• Wind pollinated but may be an important source of pollen for multiple species of pollinators



# ► In addition to pollen and/or nectar, pollinators may obtain nesting materials and occupy nesting sites in habitats subject to chlorpyrifos exposure

168

## 8/21/2013

85 

# Problem formulation and conceptual model

► Recognized the protective warnings for pollinators

on the labels.

► Focus on formulations currently used in agriculture

in the US.

► Lorsban ® 4E

► Lorsban Advanced®

► Lorsban 15G



# ► Conceptual model based on SETAC Pellston (2011) and new US EPA (2012) proposals.

169

CPY AND CPYO FROM GROUND/AERIAL SPRAY IN

AGRICULTURAL USE

CPY ON
POLLINATOR S T R E S S O R

PRIMARY
COMPARTMENTS/
ROUTES OF
EXPOSURE PRIMARY
EXPOSURE

TYPE

DIRECT
DEPOSITION
& AERIAL

DRIFT TRANSFORMATION IN ALL
MATRICES

- DETOXIFICATION

- FORMATION OF CPYO IN AIR

INHALATION
TOXICITY CPY OR CPYO SUBLETHAL
BODY BURDEN
TRANSPORTED TO HIVE
OR PROGENY

HIVE PRODUCTS (Honey, Bee Bread, Royal Jelly), Wax CPY IN POLLEN CARRIED
TO HIVE OR FOR LARVAL

FOOD

CPY ON
VEGETATION

CPY IN AIR vapor, dust/aerosol
CPYO formation

CPY ON SOIL CPY IN SURFACE

WATER

CPY, CPYO IN

RAIN WATER &
DEW ON
SURFACES
& IN POOLS CONTACT TOXICITY
BODY & TARSAL

ORAL TOXICITY

CPY, CPYO
RECONCENTRATION IN WAX (In hive) SECONDARY
MOVEMENT &
TRANSFORMATION

Grooming R E C E P T O R SOCIAL and SOLITARY POLLINATOR PROTECTION GOALS S E C O N D A R Y & D E L A Y E D O R A L
T O X I C I T Y T O H I V E B E E S , Q U E E N , D R O N E S , P R O G E N Y ( B r o o d )

CPY ON PREY

CPY IN
GROUNDWATER POLLEN

NECTAR FOLIAGE &
BUD WAX Leaf cutting,

propolis SECONDARY
EXPOSURE

TYPE

White box with dashed frame = Incomplete pathway Dashed arrow = may be insignificant for CPY, CPYO. ORAL & CONTACT
TOXICITY

PRIMARY & SECONDARY
EXPOSURE FROM SOIL (e.g. Andrenidae Osmia, Peponapis, Halictid ) CPY OR CPYO CARRIED
ON LEAF CUTTINGS USED
FOR HOUSING ( Megachilid ) GUTTATION
HONEYDEW

170 Figure 1

## 8/21/2013

86 

# Proposed protection goals

from Fischer and Moriarty 2011 

# CPY ERA
focus on hive

171



# Potential exposures of pollinators to CPY

► Formulations currently used in U.S. are

used on alfalfa, corn, cotton, soybean

, sunflower, tree nuts (e.g

., almond, pecan,

walnut )

► At least partially dependent upon pollinators, or are utilized as forage or nesting material for pollinators

172

## 8/21/2013

87 

# Direct exposure to sprays

► End

- user labels for products formulated with CPY state that CPY is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds, and that the product is not to be applied or allowed to drift to blooming 

# crops or weeds if bees are visiting the treatment

area

. ► Worst case and forage radius of honey bees

assume this will still occur to some extent

173



# Characterization of exposure

Life stage Minimum dose (μg
CPY bee

- 1 

### ) 

### Maximum dose (μg
CPY bee

- 1 

### )

Adult 7.5

– 61 30.5

– 183

Larvae 3.1

– 25 12.6

– 75 

## Tier

- 1 estimates of CPY dietary exposure in honey bees (aggregate nectar/honey and pollen consumption) during foliar applications of Lorsban 4E or Lorsban Advanced at minimum and maximum application rates based on T

- REX estimates of concentrations in pollen and nectar.

174 

## Not the best model for bees!

Table 1

## 8/21/2013

88 

# Pollen and honey

Matrix Concentration (μg kg

- 1 

### ) % of samples

Mean Median Maximum 95 th 

### centile LOD

Pollen 53 4.4 830 227 0.1 44 (153/350)

35

--- 35

--- 10.0 0.5 (1/198)

955

--- --- --- 0.1 100 (2/2)

Honey 46

--- 80

--- 4.0 42 (13/31)

--- --- 15

--- 0.8

--- ND

--- ND 3.5 0 (0/239)



### ND ND ND 5.0 0 (0/51) 

## Measured concentrations of CPY detected in pollen and honey from honey bee hives

175 Table 2



# Exposures

Life stage (consumption) Median dose (μg CPY

bee

- 1 

### ) 95 th 

### centile dose (μg CPY

bee

- 1 

### )



### Adult (292 mg) 1.28 x 10

- 3 

### 6.61 x 10

- 2



### Larva (120 mg) 5.26 x 10

- 4 

### 2.72 x 10

- 2 

## Tier

- 2 estimates of CPY exposure through daily consumption of pollen and nectar by adult and larval honey bees . Based on

values measured in diet.

176 Table 3 

## Also characterized exposures via residues on leaf ( Table 4 ), beeswax ( Table 5 , may be a sink), soil (non

- Apis bees), dew and puddles ( Table 13

)

## 8/21/2013

89 

# Exposures

Plant Time (d) Residue (μg cm

- 2 

### ) adjusted to 1.12 kg ha

- 1 

## Cotton 0 3.64

1 0.13

2 0.071

3 0.055

4 0.034 

## Tier

- 2 Dissipation and concentration of dislodgeable foliar

residues

.

Geometric means concentrations at 0 and 3

- 4 days after spraying were 1.46 and 0.019 μg cm - 2 

## (adjusted for a 1.12 kg/ha application rate)

177 Table 4



# Exposures

Matrix Mean Median Maximum 

## 95th
centile

Comb

beeswax 

### 24.5 4.3 890.0 55.7

14.9

--- 19.0

---

172

--- --- ---

8

--- 15

---

ND d 

### ND ND

---
Foundation

beeswax 

### 22.2 10.0 110.0 76.4 

## Tier

- 2 Concentrations of CPY detected comb and foundation beeswax from honey bee hives

.

Wax may be a sink for CPY and reduces exposures

178 Table 5

## 8/21/2013

90 

# Exposures via soil and puddles

► No data for soil

– more relevant to non

- apis
bees.

► Puddles (intake = 47 μL d

- 1 

# )

► Tier

- 1 rice model based on Koc and direct overspray:

► 2.40 x 10

- 7 

## μg CPY bee

- 1 

## d

- 1



## ► Tier

- 2 PRZM/EXAMS:

► 95 th 

## centile maximum daily dose 0.027 μg bee

- 1 

## d

- 1



## ► Water carrying; 0.71 μg bee

- 1 

## d

- 1



## PRZM/EXAMS based on large storm events, most years values were zero. Bees do not forage during large storm

events

– no exposure?

179 Table 13



# Exposures via dew, air and wax

► Dew Intake = 47 μL d

- 1



# ► Tier

- 1 Koc method

► 0.034 μg CPY bee

- 1 

## d

- 1



# ► Tier

- 2 LiquiPARAM

► 95 th 

## centile maximum daily dose 0.0099 μg bee

- 1 

## d

- 1



## ► Water carrying; 0.05 μg bee

- 1 

## d

- 1



# ► Air

► CPY not used as a fumigant insecticide, exposure below threshold of toxicity for bees.



# ► Wax

► No effects when exposed to contaminated comb

180

## 8/21/2013

91 

# Measures of effects

► Measured acutely (< 96 h) through
dermal contact and oral tests

► Chronic tests can use the same exposure methods
and can be done on adult bees for 10

- 14 days.

► Mortality , knockdown (i.e

., live but immobile), staggering (poorly coordinated movements) and responsiveness 

## (hypo

- or hyper

- responsive)



# ► Sublethal endpoints: learning,

behavior , physiology, impaired growth, reproduction and survival

181



# Topical toxicity (acute)

Formulation % Purity Topical LD50 (μg CPY bee

- 1 

## )

Technical ≥ 95 0.059

Technical 99% 0.115
Technical product geometric mean 0.082

Lorsban 48E 48 0.024

Dursban F 97.4 0.070

Lorsban Advanced 41.1 0.14

Dursban 480 48 0.22

Dursban WG 75 0.54
Formulated product geometric mean 0.123

182 Table 6

## 8/21/2013

92 

# Oral toxicity (acute)

Formulation % Purity Topical LD50 (μg CPY bee

- 1 

### )

Technical ≥ 95% 0.114

Lorsban 4E

--- 0.11

Dursban 4 48 0.29

Dursban 480 48 0.33

Dursban F 97.4 0.36

Lorsban Advanced 41.1 0.39

Lorsban 50WP 50 0.4

Lorsban 50W 50.2 0.46

Dursban WG 75 1.1

Formulated product geometric mean 0.36

183 Table 7



# Field studies

► Effects on Bombus impatiens observed after 14 d exposure via treated turf

► Despite short

- term lethal effects on honey bees 

# observed in field studies;

► Colonies should be able to survive such exposure with few long

- term effects

► Risk reduced or eliminated if application is not made
when flowers are open.

► Non

- Apis pollinators with females that annually establish nests, which are much smaller than that of the honey bee, are likely more sensitive to CPY

exposure.

184

## 8/21/2013

93 

# Incident data

185 Table 11 

### Crop Reported CPY incidents with honey

bees

1990

- 1999 2000

- 2009 2010

- present

TOTALS 26 4 1

Reporting of incidents is poor and critical data are frequently omitted.



# Tier

- 2 risk quotients, oral pollen

Variable Larvae (120 mg) Adults (292 mg)

Median 95 th



## centile Median 95 th



## centile Dose (μg
CPY bee

- 1 

## ) 5.26 x 10

- 4 

## 2.72 x 10

- 2 

## 1.28 x 10

- 3 

## 6.61 x 10

- 2



## LD50 0.146 0.146 0.114 0.114

RQ 0.004 0.19 0.011 0.580

186 Table 12

## 8/21/2013

94 

# Risk quotients, oral water

Variable Median 95 th centile or maximum

OCSPP

2012
dew/wet foliage Dew/wet

foliage Liqui

PARAM Tier

- 1 rice

model puddle a PRZM /

EXAMS puddle/pore

water OCSPP

2012
dew/wet foliage Dew/wet

foliage Liqui

PARAM

PEC at 1.12 kg CPY/ha ( μg L

- 1 ) 140 102 5.10 x 10

- 3 571 730 210

Dose from drinking

water ( μg bee

- 1 ) 0.007 0.005 2.40 x 10

- 7 0.027 0.034 0.010

Tier 1 RQ drinking water 

### 0.06 0.04 2.10 x

10

- 6 

### 0.24 0.30 0.09

Dose based on

water collected ( μg bee

- 1 ) 0.035 0.03 6.38 x 10

- 6 0.71 0.18 0.05

RQ for water collection by honey bees 

### 0.31 0.22 5.59 x

10

- 5 

### 6.26 1.60 0.46

187 Table 13 

### PRZM/EXAMS upper centiles from large storm events after

application; bees will not forage under these conditions.



# Risks estimated from field tests

► F oliage treated with CPY at the label rate can remain lethal to honey bees, alfalfa leaf cutting bees, and alkali bees for several days after application.

► S ome mortality may occur 1

- 2 d after application on flowering crops

► Reduced foraging may persist for up to a week

► Residues remaining after 7 d have no impact



# ► Rapid , normal turnover of foragers in hives (resiliency) and availability of alternate foraging
sites should buffer out these short

- term effects.

188

## 8/21/2013

95 

# Risks from contaminated soil

► No data for ground

- nesting bees

► Availability of residues reduced by adsorption to

soils.

► Architecture of the nest may reduce exposures.

189



# The bottom line

► CPY is toxic by direct contact but this is mitigated by label restrictions

► Reported incidents of bee kills are rare, especially
after 2000.



# ► Most important route of exposure other than

direct is via:

► Nectar

► Pollen



# ► Little risk with Tier

- 2 assessment

► Negligible risks

► Water

► Propolis and wax

190

## 8/21/2013

96 

# Thank You!!!!! Questions????

191



### John P. Giesy, Ph.D., FRSC
Professor & Canada Research Chair in Environmental Toxicology
Dept. Veterinary Biomedical Sciences & Toxicology Centre

University of Saskatchewan
Saskatoon, SK, Canada
Tel: (306) 966

- 2096 Fax: (306) 931

- 1664

Email: John.Giesy@usask.ca

Web Site: http://ww.usask.ca/toxicology/faculty_profiles/giesy_john.html



### Keith Solomon, Ph.D., Fellow ATS, Prof. Emeritus ( UofG )
Centre for Toxicology, School of Environmental Sciences

University of Guelph,
Guelph, ON, N1G 2W1, Canada

Tel: +1

- 519

- 824

- 4120 x 58792 Fax: +519

- 837

- 0442

ksolomon@uoguelph.ca

192