### 2

Given that there are several chemicals that will be included in the risk assessment, data on each are required for conduct of a risk assessment. Data gaps for DCPA and TPA are summarized

below . Additional details are pro vided in the problem formulation

.

DCPA : No aquatic chronic studies have been submitted for DCPA. DCPA is relatively persistent in the environment and has a tendency to bioaccum ul ate in aquatic organisms. Therefore, availability of chronic studies using DCPA is important to an ecological risk assessment. In addition, a number of the aquatic studies that were formerly considered to be acceptable have been downgraded to unacceptable because of evidence that the test substance was not fully dissolved and n o measurements were made to confirm test concentrations. Additional acute aquatic studies were downgraded from acceptable to supplemental, due to the failure to centrifuge the measured concentrations. The chemical properties of DCPA indicate that althoug h the test concentrations were measured, without centrifugation the dissolved soluble

test concentrations could not be estimated.

TPA: No data have been submitted on the major degradate, TPA. TPA forms at high levels relative to parent chemical

, it i s expected to be more mobile than DCPA , and is expected to be somewhat persistent . Therefore, availability of a relatively comprehensive dataset on the toxicity

and environmental fate of TPA is needed. However, a more limited testing strategy will be

con sidered in lieu of a comprehensive data submission if one is proposed

.

Manufacturing Contam in ation By

- Products : No additional data are required on the contamination by

- products because sufficient data are currently available to allow for a risk

assessmen t on these by

- products.

### 3 

# R EGISTRATION 

# R EVIEW



# P reliminary problem formulation for the environmental fate, ecological risk, endangered species and drinking water assessments

for :



# DCPA

[ dimethyl 2,3,5,6

- tetrachloroterephthalate ]

P REPARED 

### B Y 

### :

Chr istina Wendel, Biologist Wm. J. Shaughnessy, PhD, Environmental Scientist

Environmental Risk Branch II

Environmental Fate and Effects Division Office of Pesticide Programs

R EVIEWED 

### B Y 

### :

Nelson Thurman, Senior Fate Scientist Kristina Garber, Senior Effects Scientist

Environmental Risk Branch 2

Environmental Fate and Effects Division Office of Pesticide Programs

### 4 

## T ABLE OF 

## C ONTENTS



### Description of Regulatory Action

................................ ................................ .............. 6

Stressor Source and Distribution

................................ ................................ .............. 6

Pesticidal Mechanism of Action

................................ ................................ ............... 10

Conclusions from Previous Ass essments

................................ ................................ 10 Environmental Fate and Transport Characteristics

................................ ............. 12 Physico

- chemical Properties

................................ ................................ .................... 12

Environmental Fate

................................ ................................ ................................ .. 16 Environmental Transport Assessment

................................ ................................ .... 23 Monitoring Data

................................ ................................ ................................ ........ 23

Clean Water Act

................................ ................................ ................................ ........ 24 Ecological Effects

................................ ................................ ................................ ...... 25 Effects to Aquatic Organisms

................................ ................................ .................. 31 Effects to Terrestrial Organisms

................................ ................................ ............. 32 Degradate toxicity

................................ ................................ ................................ ..... 34

Contaminant tox icity (dioxins and HCB)

................................ ............................... 35 Ecological Incidents

................................ ................................ ................................ .. 37 Characteristics of Ecosystems Potentially at Risk

................................ ................. 38 Assessment Endpoints

................................ ................................ .............................. 38 Conceptual Model

................................ ................................ ................................ ..... 39 Risk Hypothesis

................................ ................................ ................................ ......... 41 Analysis Plan

................................ ................................ ................................ ............. 41

Stressors of Concern

................................ ................................ ................................ . 42 Measures of Exposure

................................ ................................ ............................... 42 Measures of Toxicity

................................ ................................ ................................ . 45

Measures of Risk

................................ ................................ ................................ ....... 46 Integration of Exposure and Effects

................................ ................................ ....... 46

Deterministic and Probabilistic Assessment Methods

................................ .............. 47 Drinking Water Assessment

................................ ................................ ..................... 47 Endangered Species Assessments

................................ ................................ ............ 47 Endocrine Disruptor Screening Program

................................ ............................... 48 Preliminary Identification of Data Gaps

................................ ................................ 49

Environmental Fate

................................ ................................ ................................ .. 49 Effects

................................ ................................ ................................ ................... 50

Other Information Needs

................................ ................................ ......................... 56

References

................................ ................................ ................................ .................. 57

### 5 List of Appendices

Appendix A. Maximum DCPA use rates and management practices by crop based on current

labels.

................................ ................................ ................................ .......................... 70

Appendix B. Output generated by SIP v.1.0

................................ ................................ ................ 79

Appendix C: Additional Information for DCI Ratio nale

................................ .............................. 80

### 6



## Description of Regulatory Action

The Food Quality Protection Act of 1996 mandated the EPA to implement a new program for assessing the risks of pesticides, i.e ., registration review 1 

### . All pesticides distributed o r sold in the United States generally must be registered by EPA. The decision to register a pesticide is based on the consideration of scientific data and other factors showing that it will not cause unreasonable risks to human health, workers, or the env ironment when used as directed on product labeling. The registration review program is intended to ensure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard o f no unreasonable adverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the new registration review program, the Agency periodically reevaluates pesticides to

ens ure that as change occurs, products in the marketplace can be used safely.

As part of the implementation of the new Registration Review p rogram pursuant to Section 3(g) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is begi nning its evaluation to determine whether d imethyl 2,3,5,6

- t etrachloroterephthalate ( DCPA) uses continue to meet the FIFRA standard for registration. This problem formulation for the environmental fate and ecological risk assessment chapter in support of the registration review is intended for the initial docket opening, which starts the public phase of the review process. This problem formulation considers all current and active registrations for DCPA

.

Problem formulation s provide a strategic framework for the risk assessment. By identifying the important components of the problem, it focuses the assessment on the most relevant life history stages, habitat components, chemical properties, exposure routes, and endpoints. The

structure of this risk asses sment is based on guidance contained in U.S. EPA’s Guidance for Ecological Risk Assessment ( U.S. EPA 1998a), the Services’ Endangered Species Consultation Handbook ( U.S. FWS /NMFS 1998) and is consistent with procedures and methodology outlined

in the Overv iew Document ( U.S. EPA , 2004) and reviewed by the U.S. Fish and Wildlife Service and National Marine Fisheries Service ( U.S. FWS /NMFS 2004).

The purpose of this problem formulation is to provide the foundation for the environmental fate and ecological ris k assessment being conducted for DCPA . It sets the objectives for the risk assessment, evaluates the nature of the problem, and provides a plan for analyzing the data and characterizing the risk

.



## Stressor Source and Distribution

DCPA (also called da c thal ) , a pre

- emergence herbicide first registered under FIFRA in 1958

, is used widely to control annual grass and certain broadleaf weeds. It is registered for a variety of food (vegetables, cole crops, herbs, melons, and others) and a variety of non

- food uses (turf, residential lawns, ornamentals, nurseries, and sod farms). The formulations currently registered include granular, wettable powders, and flowable concentrates. DCPA may be applied via ground, chemigation, and aerial applications. Application met hods include broadcast spray, soil

1 ( http://www.epa.gov/oppsrrd1/registration_review/ )

### 7

incorporation, soil band treatments, layby treatments, spreader, sprinkler irrigation, and soil

broadcast treatment and

, in general

, it is applied at seeding or transplanting or after cultivation to prevent germination of weeds. Depending on the crop, it may be applied to the crop pre

- plant, preemergence, post emergence, or post transplant (OMAFRA, 2008).

Two major degradates were observed in laboratory studies , tetrachloroterephthalic acid (TPA) and monomethyl tetrachlo roterephthalic acid (MTP). TPA reached maximums of 100% applied radioactivity and MTP maximums of 16% applied radioactivity in aerobic soil metabolism studies. TPA was also a major degradate in an anaerobic soil metabolism study , and

is stable to aerobic and anaerobic soil metabolism . MTP is an intermediate between DCPA and

TPA. MTP is short lived and degraded to TPA. Exposure to DCPA and TPA is expected to be much greater than to MTP. In addition, TPA is a known groundwater contaminant. Therefore,

t he risk assessment of degradates focuses on exposure to TPA.

The manufacturing processes of DCPA results in the form ation of several known contaminants. Of toxicological concern are hexachlorobenzene (HCB), cong e ners (structurally related chemicals) of polyhalogenated dibenzo

- p

- dioxins/dibenzofurans (dioxins/furans) , and other possible organochlorine contaminants

. D ibenzofurans and dibenzodioxins other than 2,3,7,8

- tetrachlorodibenzo

- p

- dioxin (2,3,7,8

- TCDD ) are a possible manufacturing by

- products

and were reported as a contaminant in the RED

. The risk assessment will examine potential exposures to HCB and the dioxin 2,3,7,8

- TCDD.

The following uses are considered part of the federal action that will be evaluated in this

assessment and reflect the c urrent labeled uses of DCPA

.

Terrestrial food crops

Terrestrial food crop uses include: a rrowroot, dried

- type succulent (snap) beans, brassica (head and stem vegetables), b roccoli, broccoli raab, b russels sprouts, cabbage, chinese cabbage, canola/rape, cauliflower, chayote, collards, cucumber, eggplant, garlic, gherkin, medicinal ginseng, gourd, C hinese (wax) gourd, groundcherry (strawberry tomato/tomatillo), hanover salad, horseradish, kale, head and leaf lettuce (black seeded simpson, salad bowl, etc.) , manioc (cassava), melons, watermelons, cantaloupe, honeydew, musk melons, m omordica spp., mustard, onion (including green and scallions), onion, southern peas, pepino (melon pear), pepper, white/Irish potato, radish, shallot, all or unspecified squash, s ummer squash, winter squash, hubbard squash, sweet potato, strawberry, taro, tomatillo, tomato, tumeric, turnip, and yam

.

Terrestrial non

- food crop s

Terrestrial non

- food crop uses include: g o lf course turf, nursery stock, ornamental and/or shade trees, o rnamental ground cover, ornamental herbaceous plants, ornamental lawns and turf ornamental sod farm (turf), ornamental lawns and turf, ornamental nonflowering plants, ornamental woody shrubs and vines, and residential lawns

.

### 8 USGS National Use Map

A nat ional map showing the estimated poundage of DCPA applied in 2002 is presented in Figure 1. The map was downloaded from the U.S. Geological Survey (USGS), National Water Quality Assessment Program (NAWQA) website : http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=02&map=m1872

. It does not reflect any new registrations, label changes, changing use patterns, or mitigation measures that may have occurred b etween that time and the time of this problem formulation. The map is

an illustration of the current extent of DCPA use for agricultural purposes and do es not reflect

non

- agricultural uses . The risk assessment will be based on the labeled uses at the time the

assessment is conducted.

Figure 1 . DCPA National Use Map

Label Application Rates and Intervals

DCPA labels may be cate gorized into two types: labels for manufacturing uses (including technical grade DCPA and its formulated products) and end

- use products. While technical products are not used directly in the environment, they are used to make formulated products,

which ca n be applied in specific areas to control annual grasses and broadleaf weeds. The formulated product labels legally limit DCPA’s potential use to only those sites that are specified on the labels. A complete list of all uses that will be assessed is pres ented in Table 1

. The

### 9

maximum application rate on the labels will be used to estimate exposure. When some labels had a lower maximum application rate relative to other labels, both rates are included in Table 1

.

Table 1 . DCPA Uses and Application Information

Use Sites Type of Application Maximum Single

Application Rate (lbs a.i./A) (Formulation) Application

Interval (days) Crops

Cycles per

Year 1

Brassica (head and stem vegetables), Broccoli, Broccoli raab, Cabbage, Chinese Cabbage,
Canola \ rape, Cauliflower, Collards, Horseradish, Kale,

Mustard Aerial (G only)
Ground 10.5

(WP, FlC, G) 7, 30, NA 1 to 3

Canola/rape Aerial (G only)
Ground 10.5

(WP, FlC, G) 7 1 (assumed)

Garlic, Leek Aerial (G only)
Ground 10.4 (G) 7 1

- 2

Head and Leaf Lettuce, Brussels Sprouts, Hanover
Salad Aerial (G only)
Ground 10.5

(WP, FlC, G) 183 1

- 2

Ground 10.2 (WP) 183 1

- 2

Chayote, Cucumber, Gherkin, Gourd, Chinese Gourd, Bitter Melon, Can taloupe

, Honeydew, Watermelon, Musk Melon, Mormordica

spp. 3 , Pepino, Pear Melon, Summer Squash, Melon, Winter Squash, Hubbard Squash Aerial (G only)
Ground 10.5 (WP, FlC,

G) NA 1

Aerial
Ground 10.4 (G) NA 1

Onion, Green Onion, Scallions, Radish, Shallo t, Taro, Ginseng, Arrowroot, Manioc, Tumeric Aerial (restrictions)
Ground 10.5

(WP, FlC, G) 7 Often

rotated

with lettuce

Irish Potato, Sweet Potato, Turnip, Yam, Taro, Ginseng, Arrowroot, Manioc, Tumeric Aerial (G only)
Ground 10.5

(WP, FlC, G) 7 1

Gro und 10.4 (G) 7 1 Dried type beans, succulent beans, snap beans, southern

peas, pepper Ground 10.4 (G) NA 1

Strawberry Ground 10.5 (G) NA 1

Eggplant, Groundcherry, strawberry tomato, Tomatillo,

Tomato Aerial (G only)
Ground 10.5 (FlC)

9.1 (G) 1 1

Nurs ery Stock and

ornamentals Aerial
Ground 11.4 (G)

12 (FlC, WP) 7 1 (assumed)

### 10

Use Sites Type of Application Maximum Single

Application Rate (lbs a.i./A) (Formulation) Application

Interval (days) Crops

Cycles per

Year 1

15.2 (G) 15 (FlC) Ornamentals lawns, residential lawns, turf, ornamental sod farm, shade trees, ground cover herbaceous plants, nonflowering plants, woody shrubs and vines, golf c ourse turf, residential lawns Aerial
Ground 11.4 (G)

15 (FlC) 15.2 (G) 7, 30, 60 1 (assumed)

Abbreviations: App. = application; Form. = formulation; WP = wettable powder; FlC = flowable concentrate; G = granular; a.i. /A = active ingredient /acre

1

- Seaso ns per year were obtained from Memorandum from Monisha Kaul in BEAD to Melissa Panger in EFED dated 2/28/2007, unless stated otherwise.



### DCPA may be applied at planting, transplant, post

- emergence, or post

- transplant and as a broadcast, foliar, layby, band ed, or soil incorporated application. For example, it is recommended for use after cultivation to prevent germination of weeds.

The maximum amount of DCPA applied per season was not specified on the labels for most uses. Some labels specified one appl ication of DCPA per crop cycle for lettuce but no other labels specified a maximum number of applications for any of the crops

. In addition, minimum application intervals were not specified on any of the labels. In its absence, a varied application

int erval based on crop use scenarios used in the risk assessment will be assumed by EFED.

E stimates of agricultural uses of DCPA as of June 17, 2008 are presented in Appendix A

. Changes in label allowed uses that occur between now and the time the risk asse ssment is

conducted will be reflected in the risk assessment.



## Pesticidal Mechanism of Action

DCPA is a selective phthalic acid herbicide (Wood, 2007) and chlorinated benzoic acid herbicide (Cox, 1991). DCPA inhibits both root and shoot growth of emergi ng seedlings of annual grasses and certain annual broadleaf weeds (Holmesen and Hess, 1984). It is non

systemic and is absorbed by the roots but not foliage and does not translocate in the plant (OMAFRA, 2008). DCPA disrupts mitosis resulting in abnormal cell division in the root tip meristem areas. It causes significant disruption of cell wall formation and disrupts microtubule formation and function (Monaco et al. , 2002). The direction of cell wall formation during mitosis is random within the cell, r ather than the usual straight walls formed between two daughter nuclei (Holmesen and Hess, 1984).



## Conclusions from Previous Assessments

DCPA was first registered under FIFRA in 1958 for use on turf grasses as an herbicide for the selective preemerge nce control of crabgrass and other assorted weeds ( U.S. EPA , 1998b).

### 11

Since that time more than 60 products were registered with the Agency. Given the long regulatory history with DCPA, a number of ecological risk assessments have been conducted.

Resul ts from two recent assessments are described in more detail below.

In 1998 an ecological risk assessment was completed in support of the RED ( U.S. EPA

, 1998b). In the RED assessment for D CPA ( U.S. EPA , 1998b), the Agency was unable to make an eligibility decision for the use of DCPA on turf. The Agency identified several risks of regulatory concern, and planned to undertake a full benefits assessment before determining whether such use would be eligible for re

- registration. The risks of concern included chronic risks to wild mammalian species and acute risks to freshwater and estuarine mollusks. The Agency determined that all remaining uses of DCPA did not pose an unreasonable risk to humans or the environment and were eligible for re

- registration.

To mi tigate potential risks, t he RED required :

The registrants to establish a certified upper limit for each impurity of toxicological significance ( e.g ., 15 dioxin/furan congeners) associated with the active ingredient and found to be present in any sample of the product. The registrant to produce no more than an agreed upon limit every three calendar years, beginning in January, 1997.

All fall turf uses to be dropped from the label and the maximum application rate to be

reduced to 12 lbs a.i./A.

All labels to contain surface water, ground water, and spray drift label advisories.

However, not all of these requirements are reflected on current labels

. For instance, some fall

uses on turf are still allowed on some labels, and some labels still allow for use a t 15 lbs a.i./A.

The following ecological toxicity studies were required in the RED. Dietary study with mallard ducks Avian reproduction study using the mallard duck and bobwhite quail. Vegetative vigor and seedling emergence studies for sensitive terres trial plants

These studies have been submitted and are described in this problem formulation

, however, the vegetative vigor and seedling emergence studies do not fulfill guideline requirements, and are considered data gaps. Therefore, additional terrestr ial plant studies are needed to meet this requirement

.

In 2005, the Agency ordered that several uses be terminated, effective July 31, 2005, in response to concerns of contamination of ground water with TPA. 2 

### The uses that were to be

terminated includ ed: alfalfa, arracacha, artichokes (Chinese and Jerusalem), beans, bean yam (yam bean), beets, chestnuts (soil treatment and nursery stock), chufa, citron melon, cotton, crabapples (soil treatment and nursery stock), cucumber, edible canna, garlic, ginger, leren, peas, pepper, potatoes, residential uses (turf and ornamentals), squash (including pumpkin), tanier,

2 U.S. EPA . 2005a. DCPA: Order to amend to terminate uses. Fed Reg 70 (143): 43408

- 43410. Available at http://www.epa.gov/EPA

- PEST/2005/July/Day

- 27/p14737.htm

### 12

walnuts (non

- bearing and nursery stock), and yam. Some labels still list uses on beans, nursery stock, garlic, peas, peppers, potatoes, residentia l uses on turf and ornamentals, squash, and yam.

In February 200 9

, the Agency completed an assessment of the potential direct and indirect

effects to the California red

- legged frog (CRLF) and potential modification to designated critical

habitat from uses of DCPA

. 3 

### Based on the information available at that time the Agency made a May Affect and Likely to Adversely Affect determination for the CRLF from the use of DCPA. Additionally, the Agency determined that there is the potential for modification of

CR LF designated critical habitat from the use of the chemical. The effects determinations were based on the following predicted risks: 1) R isk of acute effects to freshwater fish exposed to TPA , for all uses ; 2) Risk of acute effects to freshwater invertebrates exposed to TPA, for all uses ; 3) R isk of chronic effects to freshwater fish and invertebrates exposed to DCPA and

TPA , for all uses ; 4) Risk of effects to freshwater plants exposed to DCPA and TPA , for all uses ; 5) R isk of acute effects to small birds exposed to hexachlorobenzene (HCB) for uses with multiple applications ; 6) Risk of chronic effects to small birds and small mammals exposed to DCPA and HCB, for all uses ; and 7) Risk of effects to terrestrial plants exposed to DCPA , for all uses



## Environmental Fate and Tr ansport Characteristics

Physico

- chemical Properties

DCPA has a vapor pressure of 12.5 x10 - 6 

### and estimated Henry’s law constants ranging from

1

. 0 x10 - 3 

### to 2.2x10 - 6 

### atm

- m 3 

### /mole, indicating that it is somewhat volatile. It is slightly soluble in

water with a s olubility limit of 0.5 mg/L and has a log K OW 

### ranging from 4. 3

- 4.4 (based on FAO classification system), indicating that it has a higher affinity for organics than for water and has the potential to accumulate in organisms. The air

- water partition coeffic ient (K AW 

### ) was reported

to be 10 - 4 

### (Daly et al ., 2007a).

Two major degradates were observed in laboratory studies, tetrachloroterephthalic acid (TPA) and monomethyl tetrachloroterephthalic acid (MTP). TPA reached maximums of 100% applied radioactivity and MTP maximums of 16% applied radioactivity in aerobic soil metabolism studies. TPA was also a major degradate in an anaerobic soil metabolism study.

MTP is an intermediate between DCPA and TPA. TPA is much more soluble than DCPA with a

water solubili ty of 5780 mg/L and is stable to aerobic and anaerobic soil metabolism ( Table 4 )

. MTP is short lived and degraded to TPA. Therefore, the risk assessment of degradates will focus on exposure to TPA. The chemical identity informa tion for these compounds is shown in Table

2 and the structures are shown in Figure 2

.

3 Memorandum from Jean Holmes, ERB 2, Environmental Fate and Effects Division , to Arthur

- Jean Williams,
Associate Director, Environmental Fate and Effects Division , Subj: Effects Determinations for DCPA Relative to

the California Red

- Legged Frog and Designated Critical Habitat, dated 2/18/2009.

### 13

Table 2 . Identification Information for DCPA and its Degradates, TPA, and MTP 1

Parameter DCPA MTP TPA

Common Name Ch lorthal dimethyl Tetrachloroterephthalic acid, monomethyl; chlorthal monomethyl, monomethyl 2,3,5,6tetrachloroterephthalate Tetrachloroterephthalic acid; chlorthal; perchloroterephthalic

acid

Chemical Abstract Service (CAS)

Number 1861

- 32

- 1 887

- 54

- 7 2136

- 79

- 0

International Union of Pure and Applied Chemistry (IUPAC)

Name Dimethyl 2,3,5,6

- tetrachloroterephthalate

CAS Name Dimethyl 2,3,5,6

- tetrachloro

- 1,4

- benzenedicarboxylate 2,3,5,6

- Tetrachloro

- 1,4

- benzenedicarboxylic

acid

Synonyms Dacthal, Dacthalor, chlorothal, chlorothal dimethyl; Chlorothal dimethyl ester Chlorthal monomethyl Chlorthal

Empirical Formula C 10 H 6 Cl 4 O 4 C 9 H 4 Cl 4 O 4 C 8 H 2 Cl 4 O 4

SMILES Notation c1(c(c(c(C(OC)=O)c(c1Cl )Cl)Cl)Cl)C(OC)=O c1(c(c(c(C(O)=O)c(c1Cl)Cl)Cl )Cl)C(OC)=O c1(c(c(c(C(O)=O)c (c1C l)Cl)Cl)Cl)C(O)=O

1 Data from U.S. EPA , 1998b, U.S. EPA , 2008 a , and the U.S. National Library of Medicine CHEMIDplus Lite Online Database available at http://toxnet.nlm.nih.gov/cgi

- bin/sis/search.



### (a) DCPA (b) MTP (c) TPA

Figure 2 . Chemical structure of (a) chlorthal dimethyl (DCPA), (b) monomethyl tetrachloroterephthalic acid (MTP), and (c) tetrachloroterephthalic acid (TPA)(US EPA, 1998a)

The manufacturing process of DCPA produces several known contaminants. Of

toxi cological concern are hexachlorobenzene (HCB), congeners (structurally related chemicals)

### 14

of polyhalogenated dibenzo

- p

- dioxins/dibenzofurans (dioxins/furans) , and other possible organochlorine contaminants

. D ibenzofurans and dibenzodioxins, other than 2,3 ,7,8

- TCDD

, are possible manufacturing by

- products and were reported as a contaminant in the re

- registration eligibility decision ( RED ) (U.S. EPA, 1998b). The risk assessment will consider all impurities of toxicological concern

. The maximum level of HCB that is allowed in formulations of DCPA is 0.3 percent. Dioxin/furans do not have a maximum allowable level in formulations. The RED reported that dioxin/furans in submitted samples were below 0.1 parts per billion (U.S. EPA, 1998b).

The structure of he xachlorobenzene , 2,3,7,8

- TCDD, and base structures of dibenzodioxins

are shown in Figure 3 . Polychlorinated dioxins have a triple ring structure that consists of two benzene rings connected by a ring with two oxyg ens. O ne to four chlorine atoms may be present on each benzene ring.

(a) Hexachlorobenzene

( b ) Base structure for dibenzodioxin

(c) 2,3,7,8

- TCDD

Figure 3 . Structure of (a) Hexachlorobenzene, (b) Dibenzodioxins, and (c) 2,3,7,8

- tetrachlorodibenzo

-

p
- dioxin (2,3,7,8

- TCDD)

Table 3 provides a summary of the physico

- chemical propert ies of DCPA

, the degradates

MTP and TPA, and the impurities, HCB and 2,3,7,8

- TCDD

.

### 15

Table 3 . Summary of Physico

- Chemical Properties of DCPA, Its Degradates, and Impurities

Property DCPA MTP TPA HCB 2,3,7.8

- TCDD
Molecular Weigh t 331.97 g/mol (2) 317.94 g/mol (2) 303.91 g/mol (2) 284.79 (14) 321.9709 g/mol Melting Point 155 o C (1,2) 158.62 o C (5) 178.10 o C (5) 230 o C (14) 305

- 306 o C (13) Boiling Point Not determinable 393.09 o C (5) 426.15 o C (5) 322 o C (14) NA Bulk Density 0.75 g /cm 3 (1) NA NA NA NA

Vapor Pressure at 25 o C 0.33 mPa or 2.5 x 10 - 6 torr (1,2)

0.21 m Pa or 1.6x 10 - 7 torr

(4) 5.23 x 10 - 7 mm Hg (5) 4.89 x 10 - 8 mm Hg

(5) 1089 x 10 - 5 mm Hg at

20 °C (14) 1.5 x 10 - 9 mm Hg (12)

Henry’s Law Constant 2.2 x 10 - 6 atm

- m 3 /mol,

mea sured (1, 7)

0.001042 atm

- m 3 /mol (4) 2.11 x 10

- 10 atm

m 3 /mole (5) 6.58 x 10 - 13 atm

m 3 /mole (5) 6.84 x 10

- 4 atm

m3/mol (14)

1.30 x 10

- 3 atm

m3/mol (14) 1.62 x 10 - 5 at

- m 3 /mol (13)

Water Solubility 0.5 mg/L (1,2) 18.26 mg/L (5) 175.4 mg/L (5) 5780 mg/L (6) 3 .5

- 20 μg/L (14) 19.3 ng/L (12)

Log Octanol

– water partition coefficient (K OW ) 4.28 (1, 4) 4.40 (2) 3.19 (5) 2.13 (5) 6.18 (14) 6.80 (12)

pKa No dissociation constant at pH 2

- 12 (11) NA NA NA NA

Air

- water partition coefficient (K AW ) 10 - 4 at 25 o C (8) NA NA NA NA

Log Octanol

- air Partition Coefficient (K OA ) 8.28 at 25 o C (9)

8.45 at 25 o C (10)

8.51 at 20 o C (10) NA NA NA NA

Log Particle

- gas Partitioning Coefficient (Kp) - 4.1 (10) NA NA NA NA

Abbreviations: NA = not available (1) Data from U.S. EPA , 1998b ; (2) Data from U.S. EPA , 2008 a; (3) Data from ChemBioFinder.com ; (4) Data from Health Canada, 2008 ; (5) Data estimated from EPI Suite version 3.20 using the SMILES string from Table 2 as input ; (6) Data from Wettasi nghe and Tinsley, 1993 as reported by U.S. EPA , 1994 ; (7)

Data from U.S. EPA , 1994 (8) Data from Muir et al. , 2004 as reported by Daly et al., 2007a ; (9) Data from Muir et al ., 2004 (10) Data from Yao et al

. , 2007 ; (11) Data from U.S. EPA, 2001; (12) Data from U.S. EPA, 2003; The most reliable or definitive value reported by the review is reported; (13) Data from U.S. EPA, 2006b; (14) Data from U.S. EPA, 1998c

### 16

Environmental Fate

The primary route of degradation for the parent is aerobic metabolism. It i s stable to hydrolysis and photolysis and biotic half

- lives range from 27

- 66 days. Organic

- carbon water partition coefficients (K OC 

### s) ranging from 1863

- 3503 L/kg, indicate it is slightly mobile. Potential transport mechanisms include spray drift, runof f, volati li zation , and atmospheric transport. The moderate K OC 

### , indicates that DCPA may be present in runoff as a solute and/or bound to organic carbon in soil or sediment. Table 4 presents a summary of the environmental fate pr operties of DCPA. EFED will access existing data to obtain environmental fate data for

HCB and dioxins.

Table 4 . Summary of DCPA Environmental Fate Properties

Study Value (units) Major Deg. (maximum %) Minor Deg. 1 MRID # Study Status or Comments

Hydrolysis Stable at pH 5, 7, and 9 None 00114648 Acceptable

Direct Aqueous Photolysis No data available 00 143063

41508607 Unacceptable

Soil Photolysis Stable

TPA was Stable MTP (5.2%) 41508608 Acceptable

Aerobic Soil

Meta bolism Single First Order ( LN/Linear Fit)

Half

- life (days) TPA (100%) 2

MTP (6.9%) 00114649

Supplemented by 41648801 Supplemental due to

insufficient mass balance (70

- 114% on day 0), moisture 95% of 1/3 bar, and temperatures were 30 o C.

Half

- lives may b e long er than predicted at 75% 1/3 bar and

at 25 o C. Additionally, soils were not completely

characterized. See DER Addendum ( 02/10/2009 ) Soil With

Unextract. Without

Unextract.

Sand

Loam 55 29

Sandy Clay

Loam 66 48

Clay 57 31

TPA s table in all soils

Single First Order ( LN/Linear Fit)

Half

- life (days) TPA (100%) 3

MTP (16%) 00114652 Supplemental due to

insufficient mass balance (70

- 84% on day 0), moisture 95% of 1/3 bar, and temperatures

were 30 o C

Half

- lives may be long er than predicted at 75% 1/3 bar and

at 25 o C. Additionally, soils were not completely

characterized. See DER Addendum ( 02/10/2009 ) Soil With

Unextract Without

Unextract

Sandy

Loam 38 27

Sandy Clay

Loam 61 47

Clay 41 29

TPA stable in all so ils

Half life (days) =

92 days at 10 o C

18 days at 25 o C and 30 o C Choi et al

., 1988 Not applicable

### 17

Study Value (units) Major Deg. (maximum %) Minor Deg. 1 MRID # Study Status or Comments

Half life (days)=

16.6 days at 25 o C Wettasinghe and Tinsley,

1993 Not applicable

Anaerobic Soil

Metabolism Half

- life (days) at 30 o C = 28 clay

38 sa ndy clay loam 23 sandy loam TPA (26%) 4

MTP (<10%) 00114651

Supplemented by 41648802 Supplemental, only 3 points

sampled, conducted at 30 o C,

and at moisture levels with

95% of 1/3 bar. Dissolved oxygen and redox potential

w ere not reported. This study

i s not upgradeable. See DER update (1/17/1991) Anaerobic Aquatic

Metabolism No data available

-- -- --
Aerobic Aquatic

Metabolism No data available

-- -- --

K d

- ads / K d

- des (mL/g)

K

oc

- ads / K

oc

- des (mL/g) DCPA, not used in modeling

-- 41648803 Su pplemental due to supernatant incompletely removed and finely sieved.

See DER Addendum ( 02/10/2009 )

MTP and TPA see Table 6 and

Table 7 -- 41648804

41648805 Acceptable. Supernatant was

incompletely removed but due to low values, it was assumed

to have little influence on the

data. Finely sieved

.

DCPA see Table 5

-- 43661101 Acceptable

Terrestrial Field Dissipation No half

- l ife could be determined Not determined 41508609 Supplemental due to variability in data and low recoveries of analytical

method. See DER Addendum ( 02/10/2009 )

No half

- life could be determined Not determined 41508610 Supplemental due to data too

errati c to allow assessment of dissipation. See DER Addendum ( 02/10/2009 )

Log

- linear dissip ation half

- life = 54 days (silt loam soil) TPA Ross et al.

, 1989 Circular plot planted with

onion and then parsley.

Aquatic Field Dissipation No data available

-- -- --

Bioconcentration Factor (BCF) Bluegill Sunfish

1894 (whole fish)

777 (fillet)

2574 (viscera)

Depuration complete in 14d -- 41155716

and

41197602 Acceptable, aquarium water

DCPA concentration

increased over time. Little metabolism or degradation of

D CPA in fish tissues. A

detectable amount of demethylation was present. Metabolite was a monomethyl analog (2,3,56

-

### 18

Study Value (units) Major Deg. (maximum %) Minor Deg. 1 MRID # Study Status or Comments

tetrachloroterephthalate). Study detected small trace quantities in organic extract

concentratates of fish whole and viscera (0.62

- 1.06%).

Clam, lipid and organic carbon

normalized

126 (whole clam) -- Pereira et al

, 1996 Based on concentrations

measured in field.

Biota

- Sediment

Accumulation

Factor (BSAF)

– lipid normalized Fish median = 0.1

Bivalve median = 4.5

-- Wong et al

, 2001 Based on concentrations

measured in field

Abbreviations : Unextract .= unextractables; Deg.= degradate

1. A major degradate made up more than 10% of applied radioactivity equivalents or is toxicologically significant

. The maximum reported percent of applied equivalent s is reported in parenthesis.

2. Approximately 80% of applied radioactivity was detected at time zero and 77% as TPA at later time points. Based on this, TPA may be assumed to reach a maximum of 100% applied radioactivity (DER 5/27/1987).

3. Approximately, 83.6 % of applied radioactivity was detected at time zero and 85.0% as TPA at 96 days. Based on this, TPA may be assumed to reach a maximum of 100% applied radioactivity (DER 5/27/1987).



### Abiotic Degradation

DCPA is stab le to hydrolysis and photolysis . No sig nificant hydrolysis occurred at pH 5, 7, and 9 over 36 days (MRID 00114648). No acceptable studies examining photolysis in water

ha ve been submitted. When DCPA was exposed to a black light and fluorescent lamps with wavelengths of 255

- 360 nm on soil, lit tle degradation occurred (MRID 41508608). Based on the

soil photolysis data , it may be assumed that DCPA is also stable to aqueous photolysis.

Biotic Degradation

Aerobic soil metabolism . The primary mechanism of degradation of DCPA is via aerobic

metaboli sm, with rates dependent on temperature and level of moisture. Aerobic soil

metabolism half

- lives measured at 30 o 

### C and at a moisture level of 95% of 1/3 bar ranged from

27

- 66 days (single first order, LN/linear fit; MRID 00114649, 00114652, 41648801). Af ter 197 days, virtually all of the parent DCPA had been converted into TPA . S mall amounts of monomethyl tetrachloroterephthalic acid (MTP) were also identified. DCPA did not degrade in

steam

- sterilized soil. Open literature degradation rates are slightl y faster than those reported in submitted studies and ranged from 17

- 18 days for 25 o 

### C (Choi et al. , 1988; Wettasinghe and Tinsley, 1993). 4 

### Walker (1978) reported that the DCPA half

- life decreased by a factor of 17.9 with a soil temperature increase from 10 o 

### C to 30 o 

### C (as reported by Choi et al . 1988). Choi et
al .'s (1988) research indicated that degradation rates for DCPA reached maximums between 25

- 30 o 

### C and then declined at higher temperatures and lower temperatures ( e.g ., an optimum temperature existed for maximum degradation rates). This suggests that for DCPA, the high

4 The average half

- life in Choi et al. 's (1988) work was 18 days at both 25 o C and 30 o C, indicating that the difference in measured degradation rates between submitted and open literature studies is not due to the differences in

temperatur e.

### 19

temperature of the submitted studies did not significantly change the rate of degradation from that expected at a temperature of 25 o 

### C, the temperature of most degradation studies. Degr adation rates of DCPA at low soil moisture levels were much lower than the medium and high moisture levels while medium and high moisture levels had similar degradation rates. This suggests that once a sufficient level of moisture is reached to support ae robic metabolism, more moisture would have little effect on the rate of degradation (Choi et al ., 1988). TPA was stable

to aerobic soil metabolism. The observed half

- life for MTP was between 1 to 14 days in the sandy loam soil (MRID 00114649, 41648801 ). No data are available on aerobic aquatic

metabolism for the parent and TPA

. The aerobic soil metabolism data submitted by the registrant is considered supplemental and therefore is a data gap. Since aerobic metabolism is a primary degradation pathway th e lack of aerobic aquatic metabolism data is also considered a data gap.

Anaerobic soil metabolism : The reported anaerobic soil conditions had little effect on degradation rates with estimated half

- lives of 28

- 38 days at 30 o 

### C and a moisture level of 95% o f

1/3 bar. The high temperature and moisture level may have resulted in higher rates of degradation and reasonable anaerobic half

- lives assuming 50% slower degradat ion rates at 25 o 

### C were estimated to range from 37

- 59 days (DER 2, 1/17/1991). Additionally , redox potential and dissolved oxygen levels were not measured/reported in the study and it cannot be confirmed whether anaerobic conditions were obtained. The similarity of the anaerobic degradation rates to the aerobic degradation rates, suggest that a naerobic conditions were not achieved. TPA was the final degradate under the reported anaerobic conditions (MRID 00114651, 41648802). No data are available on anaerobic aquatic metabolism. While this technically constitutes a data gap

EFED believes that anaerobic aquatic conditions will also have little effect on degradation rates of the parent compound.

Volatility
Based on a relatively low Henry's constant (2.2 x 10 - 6 

### atm

- m 3 

### /mol) and moderately to relatively high soil/water partitioning, DCPA does not appear to have a high volatilization potential from soil (Corbin et al ., 2006). However, several published studies have shown that parent DCPA is volatile, especially from moist or wet soil (Glotfelty et al ., 1984; Ross et al.

, 1989; Majewski et al . 1991; Nash and Gish 1989). In the vapor phase, it may react slowly with hydroxyl radicals (Meylan and Howard, 1993). It may be deposited in nearby fields, areas with lower temperatures, or with wet and dry deposition. The measured log octanol

- air partitionin g coefficient (K OA 

### ) is 8.51 at 20 o 

### C and the estimated log particle

- gas partitioning coefficient was

- 4.1, indicating that DCPA is likely to remain in the gas phase in air (Yao et al ., 2007).

In a study by Ross et al. (1989), a ir samples showed that 10% o f DCPA applied moved off site as a vapor and on particles for up to 21 days after application. The volati li zation flux reached a maximum rate of 5.6 g/ha/hour (measured using the aerodynamic method). Based on flux data, 29% of DCPA was lost due to volati lization . Parsley planted on the plot 126 days after legal application of DCPA did not contain DCPA.

Majewski et al . (1991) measured air and soil concentrations of DCPA after it was applied at a rate of 7 kg/ha to a circular plot pla n ted with white Lisbo n onion. Fluxes were greatest after/during irrigation. A loss of between 1.27 and 1.59 kg per hectare out of 7 kg per hectare applied DCPA was reported . They also found that DCPA volatilization flux was very dependent

### 20

upon the soil surface moisture conte nt. High fluxes occurred immediately following irrigation. Approximately 36 to 52 percent of the total measured DCPA loss from soil was accounted for by volatilization and 26 percent by breakdown in soil during the 21 days of air sampling.

Nash and Gish ( 1989) measured pesticide decline in the atmosphere and the dissipation rate of DCPA from moist soil at different temperatures after application at 2.5 kg/ha. Volati li zation

increased 1.8 times for each 10 o 

### C increase in temperature and dissipation increase d 1.4 times. At temperature of 35 o 

### C (95 o 

### F), volatility accounted for the loss of most of the DCPA applied.

Seiber et al. (19 91 ) measured air residues of DCPA after it was applied at 11.2 kg/ha to a circular plot planted with white Lisbon onion in Califo rnia. Downwind concentrations in air ranged from 910 ng/m 3 

### on day one to 22 ng/m 3 

### on day three based on XAD resin samples. Glass fiber filters contained 420 ng/m 3 

### on day one and were at a minimum of 5.8 ng/m 3 

### on day 11.

Small amounts of DCPA were measur ed up

- wind.

Mobility

Based on McCall's classification and FAO classifications of K OC 

### values, DCPA is slightly mobile (Corbin et al ., 2006; FAO 2000). Sorption of DCPA was measured in one acceptable study in four different soils at 25 o 

### C ( see Table 5 ). Freundlich sorption coefficients (K F 

### ) ranged

from 7

- 57 L/kg and the Freundlich exponent ranged from 0.94

- 0.99. Organic

- carbon

- water partition coefficients (K OC 

### s) ranged from 1863

- 3503 L/Kg. Solid

- water distributi on coefficients (K d 

### ) calculated by the study author ranged from 8

– 60 L/kg and are near the K F 

### values as the Freundlich exponents were all near one and the isotherms were almost linear. The variability in K OC 

### values was much lower than K F 

### values and the linear relationship between K F 

### and organic matter had an r 2 

### value of 0.86. 5 

### This suggests that sorption of DCPA is strongly influenced by organic carbon.

Table 5 . Summary of Sorption Coefficients measured for DCPA (MRID 43661101)

Soil %OC K F (L/kg) 1/N K d

(L/kg) K OC

(L/kg) Ce range (mg/L) 1

Silt Loam 2.2 57 0.99 60 2577 0.001

– 0.01

Loamy Sand 0.86 30 0.94 38 3503 0.001

– 0.02

Sandy Loam 0.26 7 0.96 8 2563 0.005

– 0.05

Silt Clay Loam 1.77 33 0.96 39 1863 0.002

– 0.02

Average 32 0.96 36 2627

Standard Deviation 20 0.02 21 673

Coefficient of Variation 65% 2% 59% 26%

Lowest Value 7 0.94 8 1863

1 Ce range is the range of DCPA concentrations in water at equilibrium. This is the range of DCPA concentrations

in water that the sorption coefficients may be confidently used to predict sorption.



### Pereira et al. (1996) measured log K OC 

### s in sediments of the San Joaquin River and

Tributaries. Field K OC 

### values ranged from 316 L/kg in bed sediment (10 2.5 

### L/kg) to 851 L/kg in suspended sediment (10 2.93 

### L/kg). Sorption was measured for the parent and degradates, MTP

5 The coefficient of variation (standard deviation/mean) for K OC values was 26% versus 65% for K F values.

### 21

and TPA, in one other study. The study was determined to be supplemental for DCPA (see

Table 6 ) by EFED

. However, these are the only data available for the degradates. Th e K OC 

### values measured for DCPA have a wider range than those measured in the acceptable study but the values are similar, indicating that the values are a good preliminary estimate of sorption coefficients for the degradates

. 6 

### Based on the results of meas ured K OC 

### values in finely sieved

soils ranging from 4

- 90 L/kg , TPA and MTP are both highly mobile and will leach into ground water ( Table 7 7 and Table 8 8 ; FAO, 2000; U.S . EPA, 2001 ). Organic

- carbon water partition coefficients (K OC 

### ) values are the values that are used in the classification system. MTP and TPA

K d 

### values ranged from 0.1

– 0.3 L/kg

. Coefficients of variation (standard deviation/mean x 100) for MTP were ap proximately the same for K d 

### and K OC 

### values (49% versus 50%) and there was a linear relationship between the percent organic carbon and K d 

### values (r 2 

### = 0.9537). This indicates that organic carbon played a role in the sorption of MTP in these soils. Coeffi cients of

variation for TPA were lower for K d 

### values than for K OC 

### values (41% versus 102%) and there was not a linear relationship between the percent organic carbon and K d 

### values. This indicates that sorption of TPA was not greatly influenced by the perc ent of organic carbon in these soils.

Table 6

. Summary of Sorption Coefficients measured for DCPA in a finely sieved soil (MRID 41648803)

Soil %OC K F (L/kg) 1/N K d

(L/kg) K OC

(L/kg) Ce range (mg/L) 1

Silt Clay 1.6 70.31 0.95 90. 2 5640 0.002

- 0.02

Silt Loam 0.4 9.4 0.91 12.8 3200 0.01

- 0.095
Sandy Loam 1.8 32.14 0.94 41.6 2310 0.004

- 0.04

Sand 0.2 5.56 0.94 6.8 3400 not in DER

Average 29.35 0.93 37.9 29.35

Standard Deviation 29.72 0.02 38.1 29.72

Lowest Value 5.56 0.91 6.8 5.56

1 Ce range is the range of DCPA concentrations in water at equilibrium. This is the range of DCPA concentrations in water that the sorption coefficients may be confidently used to predict sorption.



### Table 7 . Summary of Sorp tion Coefficients measured for MTP in a finely sieved soil (MRID 41648804)

Soil %OC K F (L/kg) 1/N K d

(L/kg) K OC

(L/kg) Ce range (mg/L)

Silt Clay 1.6 0.29 1.103 0.289 18 0.09

- 2.9

Silt Loam 0.4 0.17 0.9552 0.162 41 0.09

- 3.0
Sandy Loam 1.8 0.23 0.8226 0.296 16 0.09

- 2.9

Sand 0.2 0.11 0.9907 0.087 44 0.09

- 3.0

Average 0.20 0.9679 0.209 30

Standard Deviation 0.08 0.1155 0.102 15

Lowest Value 0.11 0.8226 0.087 16
1 Ce range is the range of MTP concentrations in water at equilibrium. This is the range of MTP concentrations in water that the sorption coefficients may be confidently used to predict sorption.

6 These supplemental DCPA sorption values were not used in modeling.

### 22

Table 8 . Summary of Sorption Coefficients measured for TPA in a finely sieved soil (MRID 41648805)

Soil %OC K F (L/kg) 1/N K d

(L/kg) K OC

(L/kg) Ce range (mg/L)

Silt Clay 1.6 0.08 0.6842 0.07 4 0.1

- 9.89

Silt Loam 0.4 0.16 0.5869 0.18 45 not in DER
Sandy Loam 1.8 0.19 0.8545 0.23 13 0.1

- 9.74

Sand 0.2 0.16 0.707 0.18 90 0.1

- 9.92

Average 0.15 0.7082 0.17 38

Stand ard Deviation 0.05 0.1106 0.07 39

Lowest Value 0.08 0.5869 0.07 4
1 Ce range is the range of TPA concentrations in water at equilibrium. This is the range of TPA concentrations in water that the sorption coefficients may be confidently used to predict sorption.



### Sorption of acidic compounds is influenced by pH and the dissociation state of the compound. Generally speaking, mobility is expected to decrease with pH for weak acids as more of the compound will be present in its neutral form at lower pH. Additionally, the pH

dependent anion exchange capacity increases as pH decreases. TPA has two COOH groups and MTP has one COOH group, indicating that TPA’s sorption will be more influenced by pH than sorption of MTP. Several leaching studies performed fo r pesticide registration or re

- registration of DCPA illustrated that TPA is very mobile and more mobile in higher pH soils ( U.S. EPA

, 1994, MRID 00114650). The pKa values of MTP and TPA are not known.

Accumulation

DCPA has been detected in fish at several locations in the United States (DeVault, 1985;

DeVault et al. , 1988; Jaffé et al ., 1985; Leiker et al ., 1991; Miller and Gomes, 1974; Pereira et al

., 1994; Saiki and Schmitt, 1986; Schmitt et al ., 1985, 1990). 

### DCPA bioconcentration factors (BCFs)

in blue gill sunfish were 1894, 777, and 2574 in whole fish, edible tissue, and viscera, respectively. Little metabolism or degradation of DCPA occurred in fish tissues, although there was a detectable amount of demethylation (MRID 41155716, 41197602).

Pereira et al. (1996) estimated organic

- carbon and lipid normalized bioconcentration factors for clams based on concentrations measured in field samples. The observed bioconcentration factor was 125.9 and was lower than that predicted based on the K OW 

### ( predicted BCF = 10 3.02 

### ).

Wong et al. (2001) measured biota

- sediment accumulation factors (BSAF) for DCPA in fish and bivalves based on samples collected in the NAWQA program. Median BSAF values were

0.1 in fish and 4.5 in bivalves.

Terrestrial Field Dissipation

Gi lroy, CA : Bare ground plots of loam soil were treated up to three times with DCPA at 7.0

- 10.5 lbs. a.i. per acre (lbs a.i./A) . DCPA was detected down to the maximum sampling depth of

18

- inches in all of the plots, while the mono

- acid was not detected belo w 6 inches in any plot. TPA was detected as deep as 60 inches 552 days after the first treatment and up to 96 inches 552 days after the second treatment. TPA was found at 0.03 ppm at the 72 inch depth 552 days after the third treatment (MRID 41508609). T he study was considered supplemental.

### 23

Greenfield, CA : Bare ground plots of sandy loam soil were treated up to three times with DCPA

at 7.0

- 10.5 lbs. a.i. /A . DCPA was detected at the maximum sampling depth of 18

- inches in all of the plots, while the mono

- a cid was not detected below six inches in any plot. TPA was detected at 48 inches. In the plot treated three times, parent DCPA was again detected in the 15

- 18 inch layer. The mono

- acid was not found below 6 inches and TPA was found at 18 inches (the lowes t layer sampled). The study was considered supplemental. The data requirement is not satisfied (MRID 41508610).

Carry Over of Residues: 

### Studies show that residues of DCPA can carry over from year to year. DCPA and its two major degradates were detected on land that had five years of application (cumulative total of 94 lb/acre) and was then untreated for three years (Gershon and McClure, 1966; as reported by U.S. EPA , 2008 a ). This is also supported by the results observed in terrestrial field dissipation studies (MRID 41508609 , 4158610).



## Environmental Transport Assessment

Potential transport mechanisms include pesticide surface water runoff, spray drift, and secondary drift of volatilized or soil

- bound residues leading to deposition onto nearby or more distant ecosystems. All of these transport mechanisms are important for DCPA.

Review of the environmental fate data and physico

- chemical properties of DCPA indicate that spray drift, runoff, and volatilization are likely to be the dominant routes of expo sure. Additionally, given the physico

- chemical profile for DCPA and observed detections of DCPA in air, rainfall, and snow samples

, the potential for offsite migration through the air exists in

addition to runoff

. DCPA and especially the degradate TPA ha ve the potential to reach ground

water. In addition, from the available data, bioaccumulation is also a potential route of concern

, as observed in both fish and invertebrate samples

.

The magnitude of transport via secondary drift depends on DCPA’s abil ity to be mobilized into air and its eventual removal through wet and dry deposition of gases/particles and photochemical reactions in the atmosphere. Therefore, physicochemical properties of DCPA that describe its potential to enter the air from water or soil ( e.g., Henry’s Law constant and vapor pressure), pesticide use data, modeled estimated concentrations in water and air, and available air monitoring data will be considered in evaluating the potential for atmospheric transport of DCPA.



## Monitoring Da ta

There are a large number of studies and data available on DCPA and degradate residues in air, surface water, drinking water, ground water, tissue, rain, and snow. The most recent review of monitoring data was completed in May 2008, and reported in deta il in the 2009 California

Red

- legged Frog risk assessment of DCPA. Th at assessment examined monitoring data relevant to drinking water, food, fish, shellfish, air, and soil. The major conclusions included :

Monitoring data indicate widespread occurrence of DCPA in surface water, ground water, drinking water, and air. DCPA and TPA are one of the most commonly found

### 24

pesticides/degradates found in water samples ( U.S. EPA , 2008 a ). DCPA is typically

detected at low concentrations in remote areas where it is not used and at higher concentrations near where it is used. DCPA concentrations in water are typically well below the lifetime Health Advisory of 4000 μg/L for DCPA ( U.S. EPA , 2008 a ). Additionally, the solubility of DCPA (0.5 mg/L) is well below the adv isory level.

Non

- agricultural uses of DCPA, e.g . use in urban areas, can be a significant source of DCPA in water. Higher frequencies of DCPA detections occurred in urban areas in the midwest and higher frequencies of detection were reported in some urban areas in NAWQA surface water samples (Kolpin et al ., 1996; U.S. EPA , 2008 a ) DCPA's degradates, TPA and MTP are more commonly detected in ground water samples than DCPA. TPA is typically found at higher concentrations. TPA was the most commonly detected pesticide in the National Survey of Pesticides in Drinking Water Wells Survey ( U.S. EPA , 1998b). Degradation rates are slower at lower temperatures and DCPA residues are commonly

detected in cooler states. The re

- registration eligibility decision for DCP A stated,

"Seventeen states with DCPA residue detections could be classified as states with cooler temperatures (AK, CT, IA, IL, IN, MA, MI, MN, NH, NJ, NY, OH, OR, PA , RI, SD, and WI). States considered "warm" states with detections were California, Co lorado, and New Mexico." ( U.S. EPA , 1998b) Food was the major source of exposure to DCPA for humans ( U.S. EPA , 2008 a ).

No prospective surface water monitoring studies which specifically targeted DCPA use (application period and/or sites) were available

. Two prospective ground water monitoring studies were conducted in support of the reregistration of DCPA, including one in California. Generally, targeted monitoring data are collected with a sampling program designed to capture, both spatially and tempor ally, the maximum use of a particular pesticide. Typically, sampling frequencies employed in monitoring studies are insufficient to document peak exposure values. The lack of targeted data coupled with the fact that these data are not temporally or spatia lly correlated with pesticide application times and/or areas limit the utility of these data in estimating exposure concentrations for risk assessment purposes. Therefore

, model

- generated

values will be used for estimating acute and chronic exposure value s, and the non

- targeted monitoring data are typically used for qualitative characterizations. All open literature and water quality monitoring databases will be searched for updates since the May 2008 data retrieval.



## Clean Water Act

DCPA is identified as a cause of impairment for one water bod y listed as impaired under section 303(d) of the Clean Water Act, based on information provided at http://iasp ub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88

5

. The water body affected is Calleguas Creek Reach 5 (was Beardsley Channel On 1998 303d List). A waterbody report was completed in 2006. In addition, a Total Maximum Dail y Loads (TMDL) ha s been developed for the herbicide, based on information provided at http://iaspub.epa.gov/tmd l_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id =885&p_pollutant_group_name=PESTICIDES . More information on impaired water bodies and

TMDLs can be found at http://www.epa.gov/owow/tmdl/

.

### 25

Th e Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management Process (see: http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1

- sop.pdf), in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.



## Ecological Effects

The Agency evaluates the potential for adverse affects as a result of DCPA usage. As described in the Agency’s Overview Document (U.S. USEPA, 2004), the most sensitive endpoint for each taxon is evaluated. Assessment endpoints include direct tox ic effects on the survival, reproduction, and growth of terrestrial and aquatic life, as well as indirect effects, such as reduction in prey base and/or modification of habitat. The evaluated taxa include freshwater fish, freshwater aquatic invertebrates, birds, small mammals, terrestrial invertebrates, algae, and terrestrial plants.

T he major degradates of DCPA are tetrachloroterephthalic acid (TPA) and monomethyl tetrachloroterephthalic acid (MTP) . The toxicity data for these chemicals are limited to

mammals. The available data indicate that the adverse effects associated with TPA are much milder than those for the parent and tend to occur at doses that are lower by approximately an order of magnitude ( U.S. EPA, 2008 a )

. However, DCPA and TPA are amo ng the most commonly found pesticides/degradates in water samples (U.S. EPA, 2008a), DCPA is slightly mobile and TPA is very mobile, respectively , a nd both are persist e nt. There is no aquatic toxicity data available for the degradate TPA. In past risk as sessments for DCPA (i.e., the CRLF ESA, U.S. EPA 2009), EFED bridged the data gap using structurally similar benzoic acid herbicides (i.e., dicamba). However, for future assessments, i n the absence of toxicity data for the degradate TPA

, EFED will make hi ghly conservative assumptions when evaluating the toxicity of TPA

.

Another possible source of toxicity from the use of DCPA products is the presence of the

known impurities that result from the manufacturing process. H exachlorobenzene (HCB)

, dioxin/fu ran congeners (i.e., 2,3,7,8

- tetrachlorodibenzo

- p

- dioxin (2,3,7,8

- TCDD )) , and other possible organochlorine contaminants have been found in the DCPA herbicide formulation product s

.

The term “dioxins” is used to represent polychlorinated dibenzo

- p

- dioxin s (PCDDs) and polychlorinated dibenzofurans (PCDFs). There are 210 different congeners of dioxins (75 PCDDs and 135 PCDFs); however, only 17 congeners are considered to be of toxicological concern (listed in Table 9 ). For these 17 congeners, evidence is sufficient to conclude that a common mechanism of action, involving binding of the chemicals to the aryl hydrocarbon receptor (AHR) as the initial step, underlies 2,3,7,8

- TCDD

- like toxicity elicited by these PCDDs, PCDFs, and Polychlorinated biphenyls (PCBs) (Van den Berg et al., 1998, 2006; Hahn, 2002).

### 26

Table 9 . Dioxin congeners that are of toxicological concern. Toxicity equivalency factors for mammals, birds and fish associated with each isomer are from U

. S

. E PA 2008b

.

Congener* Mammal TEF Bird TEF Fish TEF

2378

- TCDF 0.1 1 0.05

12378

- PeCDF 0.03 0.1 0.05

23478

- PeCDF 0.3 1 0.5

123478

- HxCDF 0.1 0.1 0.1

123678

- HxCDF 0.1 0.1 0.1

234678

- HxCDF 0.1 0.1 0.1

123789

- HxCDF 0.1 0.1 0.1

1234678

- HpCDF 0.01 0.01 0.01

1234789

- HpCDF 0.01 0.01 0.01

OCDF 0.0003 0.0001 <0.0001

2378

- TCDD 1 1 1

12378

- PeCDD 1 1 1

123478

- HxCDD 0.1 0.05 0.5

123678

- HxCDD 0.1 0.01 0.01

123789

- HxCDD 0.1 0.1 0.01

1234678

- HpCDD 0.01 <0.001 0.001

OCDD 0.0003 0.001 <0.001

*Abbreviations are as follows: TCDD = tetrachlorodibenzodioxin; PeCDD = pentachlorodibenzodioxin; HxCDD = hexachlorodibenzodioxin; HpCDD = Heptachlorodibenzodioxin; OCDD = Octachlorodibenzodioxin; TCDF = Tetrachlorodibenzofuran; PeCDF = Pentachlorodibenzofuran; HxCDF = Hexachl orodibenzofuran; HpCDF = Heptachlorodibenzofuran; OCDF = octachlorodibenzofuran



### R esearch has been conducted to characterize the toxicities of PCDDs and PCDFs especially relative to each other, since these compounds are often present together in the enviro nment. Demonstrated toxic effects of 2,3,7,8

- TCDD and other similar

- acting PCDD, PCDF and PCB congeners in fish, birds, and mammals include adverse effects on reproduction, development, and endocrine functions; wasting syndrome; immunotoxicity; and mortali ty in both laboratory and field settings (U

. S

. EPA 2008 b ). Th e EPA (U

. S

. EPA 2008 b ) and the World Health Organization (Van Den Berg et al. 1998 and 2006) have established toxicity equivalency factors (TEFs) for dioxins as they relate to mammals

, to birds a nd to fish ( Table 9 ). In the TEF

ap proach, the toxicities of individual congeners are related to 2,3,7,8

- TCDD, which is the most toxic congener of dioxins to animals (U

. S

. EPA 2008 b ; Table 9 ) . For each PCDD and PCDF,

the concentration (or mass) of the chemical is multiplied by its TEF. The sum of the product for each PCDD and PCDF represents the toxicity equivalent (TEQ) concentration relative to 2,3,7,8

- TCDD ( Equation 1 ; U

. S

. EPA 2008 b ).

Equation 1

.

Dioxins , and HCB are both listed under the Stockholm Convention as Persistent Organic Pollutants (POPs). These chemicals are persistent, bi oaccumulative and subject to long range

transport. In general, chronic toxicity endpoints for mammals and birds exposed to pesticides are expressed in terms of mg pesticide/kg

- bw. The toxicity of 2,3,7,8

- TCDD is expressed in units of ng/kg

- bw, which indicates that this chemical is orders of magnitude more toxic than p esticides

### 27

which are typically assessed by OPP. To characterize the risk associated with HCB, the toxicity

of HCB will be summarized from the scientific literature . The Agency for Toxic Substances and Disease Registry (ATSDR), associated with the Center f or Disease Control (CDC), Toxicological Profile for HCB (ATSDR, 2002) will be used as one source of information in the characterization of the toxicity of HCB.

Acute (short

- term) and chronic (long

- term) toxicity information is characterized based on regi strant

- submitted studies and a comprehensive review of the open literature on DCPA . Other sources of information, including use of the acute probit dose response relationship to establish the probability of an individual effect and reviews of the Ecologic al Incident Information System (EIIS), are conducted to further refine the characterization of potential ecological effects associated with exposure to DCPA . A summary of the available ecotoxicity information and the

incident information for DCPA are prov ided below.

### 28

Table 10 and Table 9 11 summarize the most sensitive ecological toxicity endpoints based on currently available data. A preliminary evaluation of open literature, suggests that there may b e more sensitive toxicity endpoints for both aquatic and terrestrial organisms. These will be reviewed and evaluated to determine potential use in the ecological risk assessment. A brief summary of submitted data considered relevant to this ecological ri sk assessment is presented

below

.

### 29

Table 10 . Applicable DCPA endpoints for terrestrial organisms

Assessment Endpoint Measures of

Effect Species Toxicity Value Study

classification (Selection basis) Reference

(MRID)

Abundance (i.e., survival, reprod uction, and growth) of

individuals and populations of

birds Avian (single

dose) acute

oral 21

- day

LD 50 Northern

bobwhite quail ( Colinus virginianus ) LD 50 >2,250 mg a.i./kg

bw (1) Acceptable 41155705

Avian

subacute

5

- day dietary

LC 50 Northern

bobwhite quail ( Colinus virginianus ) and

Mallard duck ( Anas platyrhynchos ) LC 50 >5620 mg a.i./kg

diet (ppm) (1) Acceptable

& Acceptable 41155706

&

41155707

Avian reproduction

NOAEC Northern

bobwhite quail ( Colinus virginianus )

and Mallard duck ( Anas platyrhy nchos ) NOAEC = 1280 mg

a.i./kg

- diet (2) LOAEC = 3170 mg a.i./kg

- diet Supplemental

& Supplemental 47550001

&

47550002

Abundance (i.e., survival, reproduction, and growth) of

individuals and populations of

mammals Mammalian

acute oral (single dose)

LD 50 Rat

( Rattus norvegicus ) Acute oral LD 50 >5000

mg a.i./kg

- bw (3) Acceptable 41054808

Mammalian 2

- generation rat reproduction

NOAEL Rat

( Rattus norvegicus ) NOAEL=50 mg/kg/day

(1000 ppm) LOAEL= 250 mg/kg/day (5000 ppm) (4) Acceptable 41750103

Surv ival of

beneficial insect populations Honey bee

acute contact

LD 50 Honey bee

( Apis mellifera ) Acute contact

LD 50 >230 g/bee (5) Supplemental 00018842

Survival and growth of terrestrial plants Seedling

Emergence Tomato

( Solanum lycopersicum ) EC 25 = 5.36 lbs a.i./A (6) Supplemental 41564901

Vegetative Vigor Soybean

( Glycine max ) EC 25 > 7.5 lbs a.i./A (7) Supplemental 41440101

1 Product tested contains 100% active ingredient (Technical Grade).

2 Based on mortality, signs of toxicity, and effects on reproduction and offspring (reduction in eggs laid, eggs set, live 3

- week embryos, number hatched, the ratios of number hatched to eggs laid and to eggs set, and hatchling survival) ; Product tested

contains 98.0% active ingredient (Technical Grade).

3 Product tested contains 98.0% active ingredient (Technical Grade). 4 Based on pup weight decrements. Product tested contained 96

- 98% active ingredient (Technical Grade)

. 5 Formulation was not identified although was described as technical; however only 3.2 % mortality at 2 29.63 g/bee was observed

. 6 Most sensitive parameter is fresh weight. Product tested contained 97.8% active ingredient (Technical Grade) dissolved in 90% acetone, 10% deionized water, and 0.05% Triton X

- 100 (as a surfactant) solution . NO AEC for tomato was 0.47 lb ai/A based on fresh weight. EC 25 ’s could not be determined for all other species tested and tolerant plant species were used.

7 EC 25 ’s could not be determined for nearly all species and tolerant plant species were used. Produ ct tested contained 97.8% active ingredient (Technical Grade) dissolved in 90% acetone, 10% deionized water, and 0.05% Triton X

- 100 (as a surfactant)

. NOAEC was 7.5 lb ai/A based on fresh weight (only one parameter was measured and recorded).

### 30

Table 9 . Applicable DCPA endpoints for aquatic organisms

Assessment Endpoint Measures of

Effect Species Toxicity Value Study

classification (Selection basis) Reference

(MRID)

Survival and reproduction of

individuals and

communities of

fre shwater fish Freshwater fish

acute 96

- hr LC 50 Bluegill sunfish

( Lepomis

macrochirus )

&

Rainbow trout ( Oncorhynchus mykiss ) BG LC 50 > 6.7 mg/ L (TWA)

(> 5.4 mg /L; mean

measured) &

RT LC 50 > 6.6 mg/L (TWA) (> 4.7 mg/L; mean

measured) (1) Supplemental

& Sup plemental 41054827

&

40154826

Freshwater fish early life

- stage
NOAEC No Data

– submission of studies are needed

Survival and reproduction of

individuals and

communities of

freshwater

invertebrates Freshwater

invertebrate

acute 48

- hr LC 50 Water flea

( Daphnia magna ) EC 50 > 100 mg/L nominal

(2a) Supplemental 40098001

EC 50 = 18.02 mg/L nominal (2b) Supplemental 40098001

Freshwater

invertebrate reproductive

NOAEC No Data

– submission of studies are needed

Survival and reproduction of

individuals an d

communities of

estuarine and

marine fish Estuarine and

marine acute

fish 96

- h LC 50 Sheepshead

minnow ( Cyprinodon variegatus ) LC 50 >1 .0 m g/L (3) Supplemental 40228401

Estuarine and

marine fish reproductive

NOAEC No Data

– submission of studies are nee ded

Survival and reproduction of

individuals and

communities of

estuarine and

marine

invertebrates Estuarine and

marine

invertebrate

acute 96

- hr LC 50 Eastern oyster

( Crassostrea virginica ) EC 50 = 0. 62 m g/L (4) Supplemental 40228401

Brown shrimp ( P enaeus

aztecus ) EC 50 >1 .0 m g/L (5) Supplemental 40228401

Estuarine and

marine

invertebrate reproductive

NOAEC No Data

– submission of studies are needed

Standing crop or

biomass and growth of aquatic plants Freshwater

green algae, cyanobacteria or

di atom 96

- h

IC 50 for

biomass. Freshwater

diatom ( Navicula pelliculosa )

and/or Green algae ( Selenastrum capricornutum ) No Acceptable Data Available (6) 42882401

&

42836103

Vascular aquatic plants Duckweed

( Lemna gibba) No Acceptable Data Available (6) 42836101

1 Product tested contains 96.7% active ingredient (Technical Grade), greater than solubility limit (0.5 mg/L) , and although concentrations were measured, they were not centrifuged, and therefore do not represent total dissolved soluble concentrat ions

. 2 a Product tested contains Technical Grade material , could not determine actual exposure concentration, concentrations were not

measured.

2b Product tested contains 75% active ingredient (Dacthal W

- 75), could not determine actual exposure concentrat ion,

### 31

concentrations were not measured.

3 Product tested contains Technical Grade material , could not determine actual exposure concentration, concentrations were not measured, and therefore, the concentrations are likely at least the solubility limit (0.5 mg/L).

4 Product tested contains Technical Grade material , could not determine actual exposure concentration, concentrations were not measured, therefore the concentrations are likely at least the solubility limit (0.5 mg/L).

5 Product tested contains Tech nical Grade material , could not determine actual exposure concentration, concentrations were not measured, therefore the concentrations are likely at least the solubility limit (0.5 mg/L). 6 Test substance was not completely in solution; throughout the tes t the treatment solution appeared cloudy with white particulates; test material was neither centrifuged nor measured , therefore the studies are considered invalid, and not for use in

risk assessments

.



## Effects to Aquatic Organisms

Fish

Available freshwate r and estuarine/marine acute fish toxicity studies (MRID 41054827

, 40154826 , and 40228401 ) indicated issues with the solubility of the TGAI in water , and are not usable for quantitative assessment

. Although there were issues with the solubility of the

com pound, no mortality was observed in the treatment concentration for the rainbow trout, and 3.3% mortality was observed in treatment concentration for the bluegill sunfish. No information

is available to determine if there was or was not any mortality obse rved for the sheepshead

minnow. Given that one can assume the exposure was at least at the level of solubility and fish may have consumed or h ad contact with the precipitate. T he available data suggest that DCPA does not result in mortality to f reshwater and /or estuarine/marine fish (based on TGAI exposure) at the limit of solubility (0.5 ppm).

Estimated chronic effects of DCPA exposure for freshwater and estuarine/marine fish are uncertain because no chronic data were submitted by the registrant for fre shwater or estuarine/marine fish, and as a result th ese studies are considered to be data gap s . In the absence

of data chronic risk to freshwater and estuarine/marine fish will be assumed. Chro n ic toxicity data are important to this ecological risk asses sment given the high Kow, persistence, and

bioconcentrati o n potential of DCPA.

Aquatic Invertebrates Available acute toxicity data for freshwater and estuarine/marine invertebrates (MRID

40098001 , and 40228401 ) using the TGAI also indicated issues with solubility in water, and are not usable for quantitative assessment

. Although there were issues with the solubility of the compound, 20% of freshwater invertebrates (daphnids, scuds, and midges) were affected in the highest treatment concentration, and no information is available to determine if there was or was

not any mortality/affects observed for the estuarine/marine invertebrates (mysid, or oyster).

There is toxicity data available for the formulated product (Dacthal W

- 75) for freshwater

invertebrate s only that can be used for quantitative assessment; however, there are still

limitations with the data

. Given that one can assume the exposure was at least at the level of solubility and invertebrates may have consumed or had contact with the precipitate

, the available data suggest that DCPA may result in effects to freshwater invertebrates (based on TGAI exposure) at the limit of solubility (0.5 ppm). For estuarine/marine invertebrates, from available data, DCPA is highly toxic on an acute exposure basi s. For freshwater invertebrates, available data for the end use formulated product data DCPA is slightly toxic on an acute exposure basis.

### 32

Estimated chronic effects of DCPA exposure for freshwater and estuarine/marine

invertebrates are uncertain becaus e no chronic data were submitted by the registrant for

freshwater or estuarine/marine invertebrates , and as a result these studies are considered to be data gaps. In the absence of data chronic risk to freshwater and estuarine/marine invertebrates

will be assumed. Chronic toxicity data are important to this ecological risk assessment given the high Kow, persistence, and bioconcentration potential of DCPA.

Aquatic Plants As with the other aquatic taxa, DCPA toxicity data for aquatic plants are limited by solubility. Tier I testing was conducted with Lemna gibba, Skeletonema costatum, Navicula pelliculosa, and Anabaena flos

- aquae (MRID 42882401

, 42836103

, and 42836101 ) , and in all

tests a white precipitate w as observed

. In addition, there was large vari ability within the data that prevented the statistical analysis from detecting a significant difference even if one was

present , and are considered not usable for quantifying risk to non

- target aquatic plants

. Based on the number of target species and the adverse effects observed in the submitted aquatic plant toxicity studies, effects to aquatic plants can be expected at or below solubility. W ithout a Tier II study, it is not possible to determine the level at which no effects will occur.



## Effects to Te rrestrial Organisms

Birds One avian acute oral toxicity study is available for DCPA exposure to Northern bobwhite quail (MRID 41155705). No treatment related effects were observed during the study and the

LD 50 

### value was determined to be greater than 22 50 mg/kg

- body weight (bw). DCPA is therefore classified as practically non

- toxic to birds on an acute oral basis.

An avian sub acute dietary toxicity study was submitted for Northern bobwhite quail (MRID 41155706) , and mallard duck (MRID 41155707) . B ot h b obwhite chicks and mallard ducklings were exposed to 560, 1000, 1780, 3160, and 5620 ppm in their diet for five days. There were no treatment related mortalities at any exposure level for either the bobwhite quail or the mallard duck, and therefore the LC 50 

### wa s greater than 5620 ppm for both species

. DCPA is therefore classified as pract ically non

- toxic to birds on a sub acute dietary basis.

Avian reproductive toxicity studies were submitted for two species : mallard duck (MRID 47550002) and N orthern b obwhite quail (MRID 47550001). Both studies followed the same DCPA exposure scheme , which was 0 (control), 1280, 3170, and 8020 mg a.i./kg

- diet. There are concerns with the overall health of the test birds (both mallard duck and bobwhite quail) and the

r esults are not reliable for use in a quantitative risk assessment. Bobwhite quail were more sensitive and thirteen treatment related mortalities were observed during the study. A NOAEC of 1280 mg a.i./kg

- diet and a LOAEC of 3170 mg a.i./kg

- diet were found , based on mortality, signs of toxicity, and effects on reproduction and offspring. Treatment related reductions in multiple reproductive parameters were detected at the top two treatment levels. More specifically, reproductive and offspring effects incl uded the ratios of live 3

- week embryos to viable embryos, number hatched to live 3

- week embryos, hatchling survivors to eggs set and to number hatched, as well as survivor weights . Some animals at the higher treatment levels were

### 33

so debilitated that they were sacrificed after week 18, three weeks prior to the end of the 21

- week observation period. However, the results are not reliable for use in a quantitative risk

assessment . T herefore, avian reproductive toxicity is considered a data gap, and new studi es are needed.

Mammal s Acute mammalian toxicity studies resulted in no observable effects to rats exposed to DCPA. In an acute oral toxicity study with Sprague

- Dawley rats, no effects were observed at 5000 mg/kg

- bw throughout the 14

- day observation per iod and therefore, the acute LC 50 

### wa s greater
than 5000 mg/kg

- bw for mammals (MRID 410548 10).

In a 2

- generation reproduction study in rats (MRID 41750103), DCPA was administered in the feed to Sprague

- Dawley rats. The F0 parental generation produced two litters, F1a and F1b. The F1b generation was mated to produce two litters, F2a and F2b. There were 35 rats/sex/dose group in the F0 and F1 generations with a ten week growth phase for the F0 generation before the first mating and a ten week growth phase for the F1b generation before the first mating. There were 20 rats/sex/dose group in the F2b generation which were observed for a six week growth period.

Dietary concentrations were 0, 1000, 5000, or 20000 ppm (equivalent to 0, 50, 250, or 1000 mg/kg/da y using a 0.05 mg/kg/day per ppm conversion factor). Doses were changed to 0, 200, 500, or 20000 ppm on day 0 of lactation for the F2b litters (equivalent to 10, 25, or 1000 mg/kg/day using a 0.05 conversion factor) in order to ensure a NOAEL for F2 pup b ody weight

decrements.

The parental NOAEL is 50 mg/kg/day and the parental LOAEL is 250 mg/kg/day based upon body weight decreases , gross and microscopic changes in kidneys and lungs, and microscopic changes in liver and thyroids (MRID 41750103)

. There were no treatment

- related effects upon reproductive indices. Mating index, fertility index, pregnancy rates, and litter size were not affected by treatment. Pup body weights in the 500 ppm F2b litters were not affected by treatment. Body weight decreme nts in weaned pups were accompanied by decreased food consumption in F1 animals but not in F2 animals. There were no treatment

- related effects seen at pup necropsy. The offspring NOAEL is 50 mg/kg/day and the offspring LOAEL is 250 mg/kg/day based upon pu p body weight decrements.

Terrestrial Invertebrates A honey bee acute contact study ( f ormulation was not identified ) resulted in honey bee

LD 50 

### >230 g a.i./bee , 3.2% mortality was observed at this concentration (MRID 00018842).

DCPA is therefore class ified as practically non

- toxic to bees.

Terrestrial Plants

For Tier II s eedling emergence test with DCPA, tomato was the most sensitive test species of all (soybean, lettuce, carrot, tomato, cucumber, cabbage, oat, ryegrass, corn

, and onion) that were

tested based on fresh weight

. The tomato EC 25 

### and NOAEC values were 5.36 lbs a.i./A and 0.47 lbs a.i./A, respectively, based on fresh weight. The seedling emergence study was classified as supplemental because the test material was not applied to the max imum labeled rate, DCPA was

### 34

not applied at low enough concentrations to determine the NOAEC for corn, le ttuce, and oat radicle length, and tolerant plant species were used

.

For the Tier II vegetative vigor test with DCPA, of the ten species (ryegrass, corn, oat, onion, soybean, lettuce, carrot, tomato, cucumber, and cabbage) tested ; soybean, tomato, and cucumber were visually affected (phytotoxicity) by DCPA. Phytotoxicity (crinkled leaves, and mottled chlorosis) was observed in soybean plants at all r ates of DCPA, and slight necrosis was observed at 1.88 lbs a.i./A on both soybean and cucumber plants. Tomato plants were affected at 3.75 and 7.5 lbs a.i./A. Although phytotoxicity was observed, no treatment effects were observed with the single measure ment of fresh weight. Therefore, the soybean EC 25 

### and NOAEC values based on fresh weight were >7.5 lbs a.i./A, and 7.5 lbs a.i./A, respectively. The vegetative vigor study was classified as supplemental because the percent active ingredient was not speci fied, the material was not applied to the maximum labeled rate, only one parameter (fresh weight) was recorded and measured, and tolerant plant species were used.



## Degradate toxicity

The Health Effects Support Document for Dacthal Degradates: Tetrachl oroterephthalic Acid (TPA) and Monomethyl Tetrachloroterephthalic Acid (MTP ) summarized the data for the degradates for TPA and MTP in the following excerpts ( U.S. EPA , 2008 a )

. “Both DCPA and TPA do cause adverse health effects in laboratory animals. Cur rently, no toxicological studies are available to assess the toxicological effects of MTP (the mono

- acid degradate). Three studies in rats (30

- and 90

- day feeding studies and a developmental study) are available for TPA. The effects of exposure were mild ( weight loss and diarrhea) and occurred at doses greater than or equal to 2000 mg/kg/day. No reproductive effects were observed. The critical effects for DCPA, the parent compound, include effects on the lung, liver, kidney, and thyroid in male and female r ats in a 2

- year chronic bioassay (ISK Biotech, 1993). The available data indicate that the adverse effects associated with TPA are much milder than those for the parent and tend to occur at doses that are lower by approximately an order of magnitude. ” Page 1

- 2

“ The only noncancer health effects noted with TPA were soft stools and occult blood in urine at doses of greater than 2000 mg/kg/day (Major, 1985). Doses of 2500 mg/kg/day administered during gd 6

- 15 also caused soft stools, increased salivation, dec reased body weight gain, and decreased food consumption (Mizen, 1985). No effects were observed in the single study of MTP (Hazelton, 1961).” Page 7

- 7

“ The results from the short

- term TPA study differed from those for DCPA in a 28

- day dietary study in gro ups of five male and female Sprague

- Dawley rats given doses of 0, 250, 1000, or 2000 mg/kg/day (ISK Biotech Corp., 1990b). In the DCPA study, there was a dose

related increase in liver weight and centrilobular hypertrophy of hepatocytes. The lowest

dose te sted (250 mg/kg/day) was the LOAEL for these effects ( U.S. EPA , 1994c). The difference in the effect levels suggests that the parent DCPA is more acutely toxic than the TPA degradate. The results of a 28

- day study of MTP by Hazleton Laboratory (1961),

com parable to Hazleton’s TPA study described above, did not identify any signs of toxicity at the 1% (860 mg/kg/day) dietary dose tested.” Page 7

- 2

### 35

Based on this analysis, we concluded that TPA was less toxic than DCPA and therefore,

terrestrial risk from ex posure to DCPA is considered to encompass potential sources of risk from degradates.

No aquatic toxicity (acute or chronic, animal or plant) data are currently available for TPA

, and are required for registration review

. TPA is structurally similar to th e parent DCPA, and

other benzoic acid herbicides , and thus may retain the herbicidal mechanism of action. Since the terrestrial animal data indicate this chemical is generally toxic on a chronic exposure basis but not an acute exposure basis, these data a re critical to the future ecological risk assessments

. In the absence of toxicity data for TPA , EFED will assume equal toxicity to the parent compound,

DCPA.



## Contaminant toxicity (dioxins and HCB )

As indicated above, when using the TEQ approach, the ex posure concentration of each dioxin congener is adjusted relative to the toxicity of 2,3,7,8

- TCDD.

In 1993, EPA developed a report (interim) on the available data and methods for assessing ecological risks associated with 2,3,7,8

- TCDD (USEPA 1993). Th is section summarizes the ecological effects data for aquatic organisms that are described in that report. Because of the low solubility and high Koc and Kow values of dioxins, a more appropriate method for characterizing toxicity is based on the concentra tion of dioxin in the organism (tissue

- based residues), rather than freely dissolved in the water. Therefore, this section will report toxicity data in terms of organism concentrations.

Currently, the toxicity and risk associated with the presence of the contaminant HCB has not been fully characterized. However, information from available scientific literature, including the Toxicological Profile for HCB (ATSDR, 2002) will be used characterize the toxicity and

estimate the risk associated with the presen ce of HCB as a contaminant of DCPA

.

Fish Toxicity data are available for several species of freshwater and saltwater fish exposed to 2,3,7,8

- TCDD. A review of the data indicates that the most sensitive life stage is fish fry. According to the 1993 EPA r eport, “[T]here is no definitive evidence of adverse effects in any of the fish species tested if accumulation in eggs is less than 34 pg TCDD/g [ng TCDD/kg], the highest no observed effect level for trout fry. This likely corresponds to an accumulation in parent fish, with lipid content similar to the eggs, of less than 50 pg TCDD/g.” Based on this information, the NOAEC for effects of 2,3,7,8

- TCDD on fish fry is 34 ng/kg, which corresponds to an accumulation in parent fish (who transfer dioxins to eggs) o f <50 ng/kg. Effects to fish fry survival are expected when concentrations of 2,3,7,8

- TCDD in eggs are 50

- 500 ng/kg, which corresponds to concentrations of 75

- 705 ng/kg in parent fish. Mortality in adult fish is expected with body concentrations of 2,3,7,8

- TCDD are 1000

- 15000 ng/kg (USEPA 1993).

Aquatic Invertebrates Data are available from toxicity studies where a species of freshwater invertebrates, i.e ., the

cladoceran Daphnia magna , and a snail ( Physa sp. ) were exposed to 2,3,7,8

- TCDD. After 33

- d

expos ures, no adverse effects were observed in either species. Concentrations of 2,3,7,8

- TCDD

### 36

in the cladoceran and snail were 1,570,000 and 502,000 ng/kg, respectively (Inensee and Jones 1975; Inensee 1978). These concentrations are based on measured levels of 2,3,7,8

- TCDD in

tissues.

Aquatic Plants Data are available from toxicity studies where non

- vascular, i.e., algae (Oedogonium cardiacum) and vascular, i.e. , duckweed (Lemna minor), aquatic plants were exposed to 2,3,7,8

- TCDD. After 33

- d exposures, no to xic effects were observed in either species. Concentrations of 2,3,7,8

- TCDD in duckweed and algae were 30,700 and 2,295,000 ng/kg, respectively, without any apparent adverse effects on the aquatic plants (Inensee and Jones 1975; Inensee 1978).

These conce ntrations are based on measured levels of 2,3,7,8

- TCDD in aquatic plants.

Birds In 2003, EPA finalized a document summarizing available laboratory and field studies involving reproductive toxicity in birds that are exposed to dioxins. A review of availa ble studies indicates that exposures of birds to dioxins leads to mortality, deformity and inhibited development in offspring (USEPA 2003b).

In the Great Lakes Water Quality Initiative Criteria for the Protection of Wildlife for 2,3,7,8

- TCDD, OW also ide ntified several studies reporting toxicity data involving chronic exposures of birds to 2,3,7,8

- TCDD. From these studies, OW selected a reproduction study with the ring

necked pheasant ( Phasianus colchicus ) exposed to 2,3,7,8

- TCDD (Nosek et al. 1992a, 1992 b, 1993) to derive the avian wildlife value used for the 2,3,7,8

- TCDD criteria. In this study, female birds were dosed intraperitonieally with 2,3,7,8

- TCDD for 10 weeks at 1.4, 14 and 140 n g/kg

day. Relative to control birds, no effects were observed in the lowest two treatments, resulting in

a NOAEL of 14 n g/kg

- day. At the highest test concentration which represents the study LOAEL ( i.e., 140 n g/kg

- day), egg production was significantly reduced and mortality of embryos was significantly increased.

The NOAEL from Nosek et al. (1992a, 1992b, 1993) will be used as the chronic effect endpoint for birds exposed to dioxins. Although studies involving intraperitoneal injections are not typically used by EFED to determine measures of effects for avian reproduct ion, no feeding studies have been identified where birds were exposed to dioxins.

Mammals Chronic toxicity endpoints for mammals exposed to 2,3,7,8

- TCDD have been identified by the USEPA Office of Water (OW) for the Great Lakes Water Quality Initiative Criteria for the Protection of Wildlife (USEPA 1995). OW defined a no observed adverse effect level (NOAEL) of 1 ng/kg

- bw/day (i.e., 0.001 μg/kg

- bw/day or 1x10

- 6 mg/kg

- bw/day) for reproductive effects to mammals exposed to 2,3,7,8

- TCDD in food. This NOA EL was based on reduced fertility in first (f1) and second generation (f2) rats at the lowest observed adverse effect level (LOAEL) of 10 ng/kg

- bw/day (Murray et al. 1979).

### 37



## Ecological Incident s

A preliminary review was made on December 1, 2010, of the Ecological Incident Information System (EIIS, version 2.1.1), which is maintained by the Agency’s Office of Pesticide Programs, and the Avian Monitoring Information System (AIMS), which is maintained by the American Bird Conservancy. One incident was foun d in AIMS, however this incident is also found in the EIIS database as well. EIIS indicates a total of 2 reported ecological incidents associated with the use of DCPA (chlorthal dimethyl), the incidents involve both fish and birds.

These incidents are su mmarized in Table 10

.

The reported DCPA ( named “ chlorthal dimethyl ” in the EIIS database ) incidents occurred in

1984 and 1988. The certainty categories on the likelihood that the use of DCPA caused 2

incidents ar e both listed as possible. Both incidents also involved other chemicals besides

DCPA. Residues of both DCPA and the other chemicals involved are available for one of the incidents (B0000

- 501

- 87).

In addition to the incidents recorded in EIIS, addition al incidents may have been reported to the Agency in aggregated incident reports. Pesticide registrants report certain types of incidents to the Agency as aggregate counts of incidents occurring per product per quarter. Ecological incidents reported in ag gregate reports include those categorized as “minor fish and wildlife” (W

- B), “minor plant” (P

- B), and “other nontarget” (ONT) incidents. “Other non

- target” incidents include reports of adverse effects to insects and other terrestrial invertebrates. For DCPA there were no aggregate incidents reported by the registrant(s).

In the risk assessment, the incidents will be further evaluated to determine if the reported incidents represent current patterns of use for DCPA (chlorthal dimethyl) . Examples of

ad ditional considerations are mitigation ( e.g ., reduced application rates), product cancellations, and changes in use patterns that have occurred since the date of the reported incident(s).

Table 10 . Ecological Incidents Associated with DCPA.

Incident No. (EIIS, AIMS) Year State Magnitude Other Chemicals

Associated with

the Incident Certainty

index Comments

I000636

- 014 1984 MO UN Chlorothalonil Cyclohexamide Benomyl possible A fish kill (of an unknown magnitude) occurred in a pond on the grounds of the St. Joe Minerals Corp (a golf course). Two days before the fish kill; the golf course was sprayed with dacthal (DCPA), Daconil, Tersan, and Acti

- Dione. No analyses

of fish or water were included in the

report.

B0000

- 501

- 87

AIMS Ev ent #396

CA: P

- 1140/1161 1988 CA 112 Diazinon

Endosulfan possible Approximately 100 fish (50 catfish & 50 shad) and 12 birds (egrets) died at a pond at a duck club in Imperial County, CA, after an accidental misuse (a spill) that resulted in runoff

to a ne arby pond. The dead fish were analyzed and found to contain dacthal

### 38

Incident No. (EIIS, AIMS) Year State Magnitude Other Chemicals

Associated with

the Incident Certainty

index Comments

(DCPA) (26.3 ppm), DDE (0.11 ppm), diazinon (0.1 ppm), and endosulfan (0.92 ppm) based on whole body and fresh weight. An analysis of the water showed no pesticides present, but no

menti on was made of the time lag between the event and the sampling of the water. Analyses of the livers of several egrets showed dacthal to be present but at less than 1 ppm. Two weeks later, on May 24, several catfish were seined from the pond and high conc entrations of dacthal were found in their livers (1.77 to 9.2 ppm). The source of the incident at the pond seemed to be a nearby crop dusting loading facility.



## Characteristics of Ecosystems Potentially at Risk

The ecosystems potentially at risk are ofte n extensive in scope; therefore, it may not be possible to identify specific ecosystems during the development of a nation

- wide ecological risk assessment. However, in general terms, terrestrial ecosystems potentially at risk could include

the treated fie ld and immediately adjacent areas that may receive drift or runoff. Areas adjacent to the treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats, and other uncultivated ar eas.

Aquatic ecosystems potentially at risk include water bodies adjacent to, or down stream from, the treated site and might include impounded bodies such as ponds, lakes and reservoirs, or flowing waterways such as streams or rivers including all adja cent off

- channel habitats that are permanently or intermittently connected to flowing waters. For uses in coastal areas, aquatic habitat also includes marine ecosystems, including estuaries, embayment’s, and near shore

environments.



## Assessment Endpoints

A ssessment endpoints are defined as “explicit expressions of the actual environmental value that is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the

valued attributes of the environment that are considered to be at r isk; and 2) operationally defining the assessment endpoint in terms of an ecological entity ( i.e ., a community of fish and aquatic invertebrates) and its attributes ( i.e ., survival and reproduction). Therefore, selection of the assessment endpoints is bas ed on valued entities ( i.e ., ecological receptors), the ecosystems potentially at risk, the migration pathways of pesticides, and the routes by which ecological receptors are exposed to pesticide

- related contamination. The selection of clearly defined

ass essment endpoints is important because they provide direction and boundaries in the risk assessment for addressing risk management issues of concern. Changes to assessment endpoints

### 39

are typically estimated from the available toxicity studies, which are us ed as the measures of effects to characterize potential ecological risks associated with exposure to a pesticide, such as

DCPA

. For a summary of the terrestrial and aquatic toxicological endpoints for DCPA see

Tables 11 and 12 in the Ecological Effects se ction, respectively.



## Conceptual Model

The conceptual model is a graphic representation of the structure of the risk assessment. It specifies the DCPA release mechanisms, biological receptor types, and effects endpoints of potential concern. The concep tual models for aquatic and terrestrial exposures are shown in Figure 4 and Figure 5 , respectively. Dashed lines denote minor exposure routes.

Based on available fate and transport data for DCPA, potential transport mechanisms include surface water runoff, movement into ground water and subsequent recharge into surface water, spray drift, and volatilization and deposition to nearby fields, and long range transport in air. Significant amo unts of DCPA have been shown to volatize off the field and be deposited to nearby fields. This could lead to exposure via inhalation or deposition of DCPA on near b y areas. Volatilization and deposition on nearby fields is expected to result in lower expo sure than that estimated for runoff and spray drift for the field that DCPA is applied to and therefore, was not assessed separately

. Exposure to DCPA due to long range transport of DCPA in ground water is also discussed qualitatively. In addition to DCP A terrestrial and aquatic organisms may be exposed to the degradate TPA, and the impurities hexachlorobenzene (HCB) and dioxins/furans

, thereby increasing the bioaccumulation risk

.

### 40

Figure 4 . Conceptual Model for Pesticide Effe cts on Aquatic Systems

### 41

Figure 5 . Conceptual Model for Pesticide Effects on Terrestrial Systems



## Risk Hypothesis

A risk hypothesis describes the predicted relationship among the stressor, exposur e, and assessment endpoint response along with the rationale for their selection. For DCPA, the following ecological risk hypothesis is being employed for this national

- level ecological risk

assessment:

DCPA, when used in accordance with current labels

, can result in off

- site movement of the compound via runoff, leaching to ground water, spray drift and atmospheric transport leading to exposure of non

- target plants and animals. Direct applications to and atmospheric deposition to foliar surfaces may serv e as a major source of DCPA exposure to wildlife. Exposure in these environmental compartments will result in adverse effects upon the survival, growth, and reproduction of non

- target terrestrial and aquatic organisms. These non

- target organisms include federally

- listed threatened and endangered species.



## Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the

environment is estimated. T he use, environmental fate, an d ecological effects of DCPA are Stressor

Source

Receptors

Attribute Change DCPA applied to use site and associated degradate and impurities

Direct application Spray drift

Birds/terrestrial -

phase amphibians/ reptiles/mammals Terrestrial

insects

Individual organisms

Reduced survival Reduced growth Reduced reproduction Food chain Reduction in prey

Modification of

PCEs related to prey availability Habitat integrity Reduction in primary productivity

Reduced cover Community change

Modification of PCEs related to

habitat Terrestrial/riparian plants grasses/forbs, fruit, seeds (trees, shrubs) Runoff

Mammals/

birds Exposure

Media Soil

Ingestion/

inhalation Ingestion/

inhalation

Ingestion/

inhalation Ingestion Dermal uptake/Ingestion/

inhalatio n Long range atmospheric
transport

Root uptake

Wet/dry deposition

Terrestrial phase amphibians

- Ingestion/

inhalation

### 42

characterized a nd integrated to assess the risks. This is accomplished using a risk quotient (ratio of exposure concentration to effects concentration) approach. Although risk is often defined as the likelihood and magnitude of adverse ecological effects, the risk quot ient

- based approach does not provide a quantitative estimate of likelihood and/or magnitude of an adverse effect. However, as outlined in the Overview Document (USEPA 2004) , the likelihood of effects to individual organisms from particular uses of DCPA is estimated using the probit dose

- response slope and either the level of concern (discussed below) or actual calculated risk quotient value.

This analysis plan will be revisited and may be revised depending upon the information submitted by the public in r esponse to the opening of the Registration Review docket for DCPA.

Stressors of Concern

DCPA or dacthal, a pre

- emergence herbicide is used widely to control annual grass and certain broadleaf weeds. Two major degradates were observed in laboratory studi es, tetrachloroterephthalic acid (TPA) and monomethyl tetrachloroterephthalic acid (MTP). In addition, the manufacturing processes of DCPA results in the formation of several known contaminants. Of toxicological concern are hexachlorobenzene (HCB), cong e ners (structurally related chemicals) of polyhalogenated dibenzo

- p

- dioxins/dibenzofurans (dioxins/furans), and other possible organochlorine contaminants.

Measures of Exposure

In order to estimate risks of DCPA expos ures in aquatic and terrestrial environments, all exposure modeling and resulting risk conclusions will be based on maximum application rates

and methods cited in Table 1 and will be estimated for each use of DCPA. The environmental fate properties of DCP A along with available monitoring data indicate that runoff and spray drift may be the principle potential transport mechanisms of DCPA to the aquatic and terrestrial organisms . DCPA is also volatile and may travel to nearby fields in the air or to remote areas via long range transport. In this assessment, transport of DCPA through runoff and spray drift will

be considered in deriving quantitative estimates of DCPA. Additionally, exposure due to deposition of DCPA in precipitation and movement of DCPA an d TPA into ground water will be qualitatively assessed. Bioaccumulation may occur; however, rapid depuration was observed in fish and residues measured in organisms are very low (MRID 41155716, 41197602). Therefore, we do not expect bioaccumulation of DC PA to be a major exposure pathway

. However, this measure of exposure will be looked at more closely during the risk assessment.

Measures of exposure are based on aquatic and terrestrial models that predict estimated environmental concentrations (EECs) of DCPA using maximum labeled application rates and methods of application. The models used to predict aquatic EECs are the Tier I model GEN eric

E stimated E nvironmental C oncentration (GENEEC) and the Tier II Pesticide Root Zone Model coupled with the Exposu re Analysis Model System (PRZM/EXAMS). PRZM ( currently version 3.12.2; 5/15/05 ) and EXAMS (currently version 2.98.04.06; 4/25/05 ) are simulation models coupled with the linkage program shell: PE5 ( P RZM E XAMS Model Shell; v 5 .0; 11/15/06), which incorporate s the standard scenarios developed by EFED. The models generate daily exposures and calculated 1

- in

- 10 year EECs of DCPA and separate EECs for its two major degradate s, TPA and MTP, which may occur in surface water bodies adjacent to application

### 43

sites

. T he major degradates of DCPA (TPA and MTP) are not naturally

- occurring compounds and are formed in significant quantities. Degradates will likely be modeled using the total toxic residue approach unless data are submitted that suggest the degradates are no t a toxicological

concern.

PRZM simulates pesticide fate and transport as a result of leaching, direct spray drift, runoff and erosion from an agricultural field, and EXAMS estimates environmental fate and transport of pesticides in a surface water body f or a 30

- year period. The combined model is designed to estimate pesticide concentrations found in water (standard pond) at the edge of the treated field. As such, it provides high

- end values of the pesticide concentrations that might be found in ecologic ally sensitive environments following pesticide application. The location of the field is specific to the crop being simulated using site

- specific information on the soils, weather, cropping, and management factors associated with the scenario. The crop/l ocation scenario is intended to represent a high

- end exposure site on which the crop is normally grown. Based on historical rainfall patterns, the receiving water body receives multiple runoff events during the years simulated. Weather and agricultural p ractices are simulated for 30 years so that the 10

- year exceedance probability at the site can be estimated. The simulation is generated using 30 years of meteorological data, encompassing the years from 1961 to 1990. Additional information

on these model s can be found at: http://www.epa.gov/oppefed1/models/water/index.htm

.

The standard scenario s used for ecological pesticide assessments assume application to a 10

- hectare agricultural fiel d that drains into an adjacent 1

- hectare water body that is 2 meters deep (20,000 m 3 

### volume) with no outlet. PRZM/EXAMS is used to estimate screening

- level exposure of aquatic organisms to DCPA . The measure of exposure for aquatic species is the 1

- in

- 10 year return peak or rolling mean concentration. The 1

- in

- 10 year peak is used for estimating acute exposures of direct effects to aquatic organisms. The 1

- in

- 10

- year 60

- day mean is used for assessing chronic exposure to fish and aquatic

- phase amphibians. The 1

- in

- 10

- year 21

- day mean is used for assessing chronic exposure to aquatic invertebrate s.

Ex posure estimates for terrestrial animals assumed to be in the target area or in an area exposed to spray drift are derived using the T

- REX model (version 1. 4 .1

, 10 /0 9 /200 8 ). This model incorporates the Kenega nomograph, as modified by Fletcher et al. (1994), which is based on a large set of field residue data. The upper limit values from the nomograph represent the upper bound of residue v alues from actual field m easurements (Hoerger and Kenega 1972). The

Fletcher et al. (1994) modifications to the Kenega nomograph are based on measured field residues from 249 published research papers, including information on 118 species of plants, 121

p esticides, and 17 chemical classes.

EECs for terrestrial plants inhabiting dry and wetland areas are derived using TerrPlant (version 1.2.2, 12/26/2006). This model uses estimates of pesticides in runoff and in spray drift

to calculate EECs. EECs are based upon solubility, application rate and minimum incorporation depth.

In general, deposition of drifting or volatilized pesticides is expected to be greatest close to the site of application. Two spray drift models, AgDisp and AgDRIFT are used to as sess exposures of terrestrial plants to DCPA deposited in terrestrial habitats by spray drift. AgDisp

### 44

(version 8.13; dated 12/14/2004) (Teske and Curbishley 2003) is used to simulate aerial and ground applications. AgDrift (version 2.01; dated 5/24/2001) is used to simulate spray blast applications to orchard crops

. The distance of potential impact away from the use sites is determined by the d istance required to fall below the LOC for chronic effects to small mammals consuming short grass.

Aquatic expos ure to the impurities, HCB and dioxins, will be characterized. PRZM/EXAMS

will be used to estimate screening

- level exposure of aquatic organisms to these compounds

. Terrestrial exposure to HCB and 2,3,7,8

- tetrachlorodebenzo

- p

- dioxin (TCDD) will be estimat ed using TREX , and KABAM, as bioaccumulation is a major transport pathway for these

chemicals . The application rate input value will be either the maximum allowed amount of the impurity in the final formulation or an upper estimate of the amount in the fi nal formulation

, respectively

.

The S creening I mbibition P rogram (SIP v.1.0, Released June 15, 2010) was used to calculate an upper bound estimate of exposure using DCPA ’s solubility ( 0.5 ppm), the most sensitive

acute and chronic (not available) avian tox icity endpoints (Bobwhite Quail with LD 50 

### > 2250 mg/kg

- bw)

, and the most sensitive acute and chronic mammalian toxicity endpoints (Rat LD 50 

### >5000 mg/kg

- bw and NOAEL = 1000 mg/kg

- bw, respectively ). Drinking water exposure alone was determined not to be a po tential pathway of concern for avian and mammalian species on an acute basis, and mammalian species on a chronic basis. Risk cannot be precluded for avian species on a chronic basis, as there is no acceptable avian reproduction data available for DCPA.

Re sults for mammalian and avian species are presented in Table 11 and Table 12 respectively.

Table 11 . Mammalian SIP Results

Parameter Acute Chr onic
Upper bound exposure (mg/kg

- bw) 0.0860 0.0860
Adjusted toxicity value (mg/kg

- bw) 3845.8028 769.1606
Ratio of exposure to toxicity 0.0000 0.0001

Conclusion* Drinking water exposure alone is NOT a potential concern for

mammals Drinking water exposur e alone

is NOT a potential concern for

mammals



### Table 12 . Avian SIP Results

Parameter Acute Chronic
Upper bound exposure (mg/kg

- bw) 0.4050 0.4050
Adjusted toxicity value (mg/kg

- bw) 1620.9664 0.0000
Ratio of exposure t o acute toxicity 0.0002 0.0000

Conclusion* Drinking water exposure alone is NOT a potential concern for

birds Due to insufficient data, risk cannot be precluded

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposu re. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non

- target animals.

### 45

This pathway will be explored further w ith the development of SIP v.2.0 in the Ecological

Risk Assessment for DCPA . For a sample of the output generated by SIP v.1.0, please see Appendix B

. Detailed information about the SIP v.1.0, as well as the tool, can be found on the

EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial

.

The S creening T ool for I nhalation R isk (STIR v .1.0, November 19, 2010) could not be used to calculate an upper b ound estimate of exposure as no valid mammalian inhalation data was

available. Th e inhalation pathway via spray drift of the pesticide may be of potential significance for avian and mammalian species given DCPA’s vapor pressure and method of application

. In addition, without a valid mammalian inhalation study available the potential differences in toxicity via the inhalation route as compared to the oral cannot be estimated. Therefore, an acute avian inhalation toxicity test is being requested for the bo bwhite quail . Th is study will aid in evaluating this pathway of concern for avian taxa. If inhalation acute toxicity data are not submitted for birds, then risk to birds from acute inhalation exposure to DCPA will be presumed.

Measures of Toxicity

Ec ological effect data are used as measures of dir ect and indirect effects to biological

receptors . Data were obtained from registrant

- submitted studies . Also, prior to completion of the risk assessment, literature studies identified by ECOTOX will also be incorporated as appropriate . The ECOTOXicology database (ECOTOX) will be searched in order to provide more ecological effects data to bridge existing data gaps. ECOTOX is a source for locating single chemical toxicity data and potential chemical mixture t oxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and Development, and the National Health and Environmental Effects Research Laboratory's Mid

- Continent Ecology Division ( USEPA 2007 d ).

Information on the potential effects of DCPA on non

- target animals is also collected from the Ecological Incident Information System (EIIS; USEPA 2007 c ). The EIIS is a database containing adverse effect (typically mortality) reports on non

- target organisms where such effects have been associated with the use of pesticides.

Where available, sublethal effects observed in both registrant

- submitted and open literature studies will be evaluated qualitatively. Such effects have included beha vioral changes ( e.g. , lethargy, changes in coloration and effects olfaction). Quantitative assessments of risks, though, are limited to those endpoints that can be directly linked to the Agency’s assessment endpoints of impaired survival, growth and repro duction.

The assessment of risk for direct effects to non

- target organisms makes the assumption that toxicity of DCPA to birds is similar to terrestrial

- phase amphibians and reptiles . The same assumption is made for fish and aquatic

- phase amphibians

.

The acute measures of effect use d for animals in this screening

- level assessment are the

LD 50 

### , LC 50 

### and EC 50 

### . LD stands for "Lethal Dose", and LD 50 

### is the amount of a material, given all at once, that is estimated to cause the death o f 50% of the test organisms. LC stands for

“Lethal Concentration” and LC 50 

### is the concentration of a chemical that is estimated to kill 50%

### 46

of the test organisms. EC stands for “Effective Concentration” and the EC 50 

### is the concentration

of a chemical tha t is estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic measures of exposure for listed and non

- listed animals are the

NOAEL/NOAEC and NOEC. NOAEL stands for “No Observed

- Adverse

- Effect

- Level” and refers to the hig hest tested dose of a substance that has been reported to have no harmful (adverse) effects on test organisms. The NOAEC ( i.e. , “No

- Observed

- Adverse

- Effect

Concentration”) is the highest test concentration at which none of the observed effects were

statis tically different from the control. The NOEC is the No

- Observed

- Effects

- Concentration.

For non

- listed plants, only acute exposures are assessed ( i.e. , EC 25 

### for terrestrial plants and EC 50 

### for aquatic plants); for listed plants, either the NOAEC or EC 05 

### i s used.

The Agency will conduct a search of the open literature to ensure that all best available science is utilized. The Agency uses the ECOTOX database as its mechanism for searching the open literature for ecological effects information. ECOTOX in tegrates three previously independent databases

- AQUIRE, PHYTOTOX, and TERRETOX

- into a system which includes toxicity data derived predominately from the peer

- reviewed literature, for aquatic life, terrestrial plants, and terrestrial wildlife, respectiv ely.

Measures of Risk

P reviously completed screening level risk assessments and exceedances of Agency levels of concern indicate a need to further examine and refine phytotoxic risk to aquatic and terrestrial plant species. Analysis of potential indirect effects on listed species (both aquatic and terrestrial) is also required. This analysis plan will be revisited and may be revised depending upon the data available in the open literature and the information submitted by the public in response to the

ope ning of the Registration Review docket.

Use information will be retrieved from registration labels and used as inputs for estimating exposure concentrations from the various use scenarios. DCPA ’s use patterns (aerial application) suggest potential risk c oncerns to non

- target aquatic and terrestrial plants. The range of potential exposure to DCPA to non

- target plants can vary on application method (aerial or ground), application rate, and use pattern.

Integration of Exposure and Effects

Risk characteri zation is the integration of exposure and ecological effects characterization to determine the potential ecologic al risk from the use of DCPA on crops listed in Table 1 and the

likelihood of direct and indirect effects to non

- target organisms in aquatic an d terrestrial habitats. The exposure and toxicity effects data are integrated in order to evaluate the risks of adverse ecological effects on non

- target species. For the assessment of DCPA risks, the risk quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are divided by acute and chronic toxicity values. The resulting RQs are then compared to the Agency’s LOCs (USEPA 2004). These criteria ar e used to indicate when DCPA ’s uses, as directed on the label, have the potentia l to cause adverse direct or indirect effects to non

- target organisms

. As noted previously, where data are lacking on the toxicity of DCPA, risk will be presumed.

### 47 Deterministic and Probabilistic Assessment Methods

The quantitative ass essment of risk will primarily depend on the deterministic point

- estimate based approach described in the risk assessment. An effort will be made to further qualitatively describe risk using probabilistic tools that the Agency has developed. These tools have been reviewed by FIFRA Scientific Advisory Panels and have been deemed as appropriate means of refining assessments where deterministic approaches have identified risks.



## Drinking Water Assessment

A drinking water assessment will be conducted to suppo rt future human health dietary risk assessments of DCPA. The drinking water assessment will incorporate model estimates of

DCPA in surface water and ground water. Concentrations of DCPA residues in surface waters will be estimated using PRZM/EXAMS. The major degradates

, TPA and MTP, are not naturally

- occurring compounds and may be formed in significant quantities. These degradates have not been considered in previous drinking water assessments, however, this will be revisited during the risk assessment process.

An Estimated Drinking Water Concentration (EDWC) of DCPA residues in ground water

will be developed. Since DCPA/TCP are among the most frequently detected pesticides in groundwater, in all likelihood, SCI

- GROW will not be used. EFED will likely use available monitoring and a refined/Tier 2 groundwater model that is currently being finalized. Output from

that model represents the concentrations that might be expected in shallow unconfined aquifers under sandy soils, which is representative of the ground water most vulnerable to pesticide contamination likely to serve as a drinking water source.

The drinking water assessment will also include available surface and ground water monitoring data with consideration of changes in use patterns tha t may have occurred. States are encouraged to submit monitoring data for review.



## Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to Federally

- listed thre atened and/or endangered (listed) species from registered uses of DCPA . This assessment will be conducted i n accordance with the Overview Document (USEPA, 2004), provisions of the ESA, and the Services’ Endangered Species

Consultation Handbook (USFWS/NMFS , 1998).

The action area is used to identify all listed (threatened and endangered) species and designated critical habitat that could be affected by the Federal action. The Federal action is the authorization or registration of pesticide use or uses as described on the label(s) of pesticide products containing a particular active ingredient. The action area is defined by the Endangered Species Act as, “all areas to be affected directly or indirectly by the Federal action and not merely the immediate are involved in the action” (50 CFR §402.2). Based on an analysis of the Federal action, the action area is defined by the actual and potential use of the pesticide.

### 48

In the case of nationwide ecological risk assessment conducted for DCPA under Registration Review, the action area will encompass the entire U nited S tates and its territories. The purpose of defining the action area as the entire U nited S tates and its territories is to ensure that the initial area of consideration encompasses all areas where DC PA may be used now and in the future, including the potential for off

- site transport via spray drift and downstream dilution. Additionally, the concept of a nationwide action area takes into account the potential for direct and indirect effects and any po tential modification to critical habitat based on ecological effect measures associated with reduction in survival, growth, and reproduction, as well as the full suite

of sublethal effects available in the effects literature. It is important to note that the nationwide action area does not imply that direct and/or indirect effects and critical habitat modification are expected to or are likely to occur over the full extent of the action area, but rather to identify all listed species and critical habitat t hat may potentially be affected by the action. The Agency will use more rigorous analysis including consideration of available land cover data, toxicity data, and exposure information to determine areas where individual listed species and designated

criti cal habitat may be affected or modified via endpoints associated with reduced survival, growth, or reproduction.



## Endocrine Disruptor Screening Program

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor Screening Program (EDS P) to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator ma y designate.” The EDSP employs a two

- tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrogen, androgen, and or t hyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine related effects caused by the substance, and

establish a dose

- response relationship between the dose and the E, A, or T effect.

Between Octob er 2009 and February 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. This list of chemicals was selected based on the potential for human exposure thro ugh pathways such as food and water, residential activity, and certain post

- application agricultural scenarios. This list should not be construed as a list of known or likely endocrine disruptors.

DCPA is among the group of 58 pesticide active ingredient s receiving EDSP test orders. For information on the status of the orders issued under the EDSP for each chemical, please visit our website at http://www.epa.gov/endo/ and click on the "Status of EDSP Orders/DCIs" in the Highlights Box. Additional inform ation on the EDSP, including the policies and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 screening battery, can also be found at this

website.

### 49



## Preliminary Identification of Data Gaps

Environmental Fate

Several environmental fate studies have not been submitted, including: a cceptable studies on the photolysis of DCPA in water, aerobic aquatic metabolism, anaerobic soil metabolism, and anaerobic aquatic met abolism. Additionally, anaerobic soil metabolism studies and terrestrial field dissipation studies were considered supplemental and therefore, the value of the information provided in the studies is limited. The photolysis data for soil indicate that DCP A is most likely stable to photolysis in water and an assumption that DCPA is stable was made. Metabolism in the aerobic aquatic environment was estimated using the aerobic soil study which was conducted under very moist conditions and at high temperature s (30 o 

### C). DCPA was

assumed to be stable to anaerobic metabolism because it is not known if an anaerobic environment was present in the submitted study. While data from terrestrial field dissipation studies do not allow the calculation of dissipation rate s, they do provide some information on the degradates of concern likely to be found in the environment and on the mobility of DCPA and TPA. Any future terrestrial field dissipation study should include measurement of the

volatilization of DCPA

TPA, a maj or degradate of DCPA, did not undergo any degradation in the aerobic soil metabolism study. It is more stable and more water soluble than DCPA and thus, higher exposure concentrations are likely. Little data are available on the environmental fate or tox icity

of TPA.

The final environmental fate data gaps involve label information. The labels do not specify a maximum number of applications or a minimum application interval. Assumptions w ill be made using the best information available for each use s cenario. However, conservative assumptions will be unless labels are clarified to specify maximum annual application rates.

The status of environmental fate studies for the parent compound is presented in Table 1 7

. In addition to the data gaps noted for the parent, EFED notes the need for a full suite of studies, with the exception of soil photolysis, for the TPA degradate. EFED does not anticipate requiring any environmental fate

- related data for HCB and dioxin. The following studies are required for the TPA degradate:

Guideline 835.2120 Hydrolysis

Guideline 835.2240 Aqueous Photolysis

Guideline 835 4100 Aerobic Soil Metabolism

Guideline 835 4200 Anaerobic Soil Metabolism

Guideline 835 4300 Aerobic Aquatic Metabolism

Guideline 835 4400 Anaerobic Aquati c Metabolism

Guideline 835 1230/40 Adsorption/ desorption and L eaching

Guideline 835 6100 Terrestrial Field Dissipation

Guideline 835 1730 Fish B ioconcentration

### 50

Table 13 . Environmental fate data requirement table for parent DCPA

OP PTS

Guideline Data

Requirement Submitted Studies

(MRID) Classification Data Gap? Comments

835.2120 Hydrolysis 00114648 Acceptable No

835.2240 Aqueous

photolysis 143063 ; 41508607 Unacceptable No Technically, this is a gap in guideline studies; however, t here is not much evidence that photolysis is going to be a route. Therefore, we will continue to assume stability.

835.2410 Soil photolysis 41508608 Acceptable No

835.4100 Aerobic soil

metabolism 00114649 ;

41648801 ; 00114652 Supplemental No Data from a new study would be of limited utility

835.4200 Anaerobic soil

metabolism 00114651 ; 41648802 Supplemental No Data from a new study would be of limited utility

835.4300 Aerobic aquatic

metabolism No studies Yes Data are needed

835.4400 Anaerobic aquatic

metabolism No studies No Data from a new study would be of limited utility

835.1230

835.1240 Adsorption/

desorption and leaching 41648803 Supplemental

No 41648804 Acceptable

43661101 Acceptable

835.6100 Terrestrial field

dissipation 415086 09 Supplemental

Yes The field studies, though limited, suggest that DCPA/TPA may persist longer than what is predicted in the lab metabolism studies. A new study could be used to confirm persistence of both parent AND degradates. In the absence of such da ta,
EFED assumes that DCPA moves off site

because of the evidence from field

measurements. 41508610 Supplemental

850.1730 Fish

bioconcentration 41155716 Acceptable No



### Effects
Although many submissions have been made to provide data on the effects of DCPA to aquatic and terrestrial organisms, numerous data gaps exist ( Table s 18 , 19 and 20 ). Previously submitted acute toxicity data for DCPA has been found to be insufficient for use in quantitative assessment, and as a result new acute aquatic toxic ity data for fish, aquatic invertebrates, and aquatic plants (vascular and non

- vascular) are needed. Chronic aquatic toxicity data for fish or aquatic invertebrates for DCPA were never submitted by the registrant. Chronic toxicity data in particular are i mportant to this ecological risk assessment given the high Kow, persistence, and bioconcentration potential of DCPA. In addition, submitted chronic avian reproductive toxicity

data were found to be insufficient and not reliable for use in a quantitative r isk assessment , t here are questions regarding the health of the birds and as a result new chronic avian toxicity studies

are needed

.

### 51

Due to the potential for persistence and movement into water for both the parent, DCPA, and the degradate, TPA, a full sui te of aquatic toxicity (both acute and chronic) data are needed to evaluate the potential risk to freshwater and estuarine/marine fish, aquatic invertebrates, and aquatic plants, resulting from use of DCPA, and subsequent degradation to TPA

.

The log K

o w 

### of DCPA is 4.28

- 4.40 and therefore, as the log K

ow 

### is greater than 3 for the parent DCPA, the data requirement of both freshwater and marine whole sediment acute toxicity data was triggered.

A major uncertainty is the amount of dioxins and HCB in techn ical DCPA, therefore more

information is needed to characterize risk to non

- target organisms relative to the amount of the contaminant(s) they are exposed to.

A cute avian oral toxicity data need to be submitted for a passerine species exposed to DCPA

. Al though t he available acute oral toxicity data for bobwhite quails, when compared to estimated environmental concentrations, indicate that levels of concern are not exceeded for birds on an

acute basis , the high application rate of DCPA indicate that any sm all change in toxicity could result in a change to the risk conclusions

. In addition, passerine species have higher metabolic rates due to their smaller sizes, than either waterfowl or upland game bird species and because they may utilize different metabo lic pathways, they may be more sensitive to DCPA

. In order to properly characterize risk to passerines, an avian oral toxicity test is required for passerine birds.

DCPA is considered to be volatile, and is frequently found at great distances from appli ed field locations. As a result, more information is needed to evaluate other potential exposure pathways to non

- target av ian species. In addition, there is no valid mammalian inhalation study available to estimate potential differences in toxicity via t he inhalation route as compared to the

oral. Therefore, an acute avian inhalation toxicity test is being requested using the most sensitive avian species as shown by avian acute oral studies. The study being requested will aid in evaluating this pathway of concern for avian taxa. An avian inhalation study protocol must be submitted for review and approval by the Agency prior to initiation of this study. If inhalation acute toxicity data are not submitted for birds, then risk to birds from acute inhalation exposure to DCPA will be presumed.

As an herbicide, it is important to identify the potential risk to non

- target plants. A revised terrestrial plant study was requested by the Agency using different plant species at publication of

the RED in 199 8 for D CPA. At this date, these studies have not been submitted and therefore are considered data gaps . Without submission of these data, it is not possible to make an effects determination for plants or animals that depend on plants for food or shelter.

Mor e thorough rationale for the data is contained in Appendix C

. There will be a revision of the risk assessment in the event that new or revised information becomes available that changes the outcome or determinations made in this document. The following da ta needs may result in reassessment of risks. Other changes may be made if current information is substantially re

evaluated.

### 52

The terrestrial studies listed below are requested for the parent, DCPA, and the seedling emergence study is also requested for its major degradate, TPA

, to increase certainty in the risk

estimation.

Guideline Number: Non

- guideline , Study Title: Avian Inhalation Toxicity , DCPA

only. Guideline Number: 850.2100, Study Title: Acute Avian Oral Toxicity Test using a Passerine species , D CPA only

. Guideline Number: 850.2 3 00, Study Title: Avian Reproduction, T wo species, DCPA only

. Guideline Number: 850. 4100 , Study Title: Tier II Seedling Emergence Toxicity Testing

– Terrestrial Plants, non

- tolerant species, extended study time (28

- days).

Guideline Number: 850. 4150 , Study Title: Tier II Vegetative Vigor Toxicity Testing

– Terrestrial Plants, non

- tolerant species, extended study time (28

- days).

The full suite of aquatic toxicity studies below are requested for the parent, DCPA, and its majo r degradate, TPA

, to increase certainty in the risk estimation

.

Guideline Number: 850.1010, Study Title: Acute Toxicity to Freshwater Invertebrates, Daphnid ( Daphnia magna ) is the preferred species. Guideline Number: 850.1025, Study Title: Oyster ( Crasso strea virginica ) Acute Toxicity Test (shell deposition) Guideline Number: 850.1035, Study Title: Mysid ( Mysidopsis bahia ) Acute Toxicity

Test Guideline Number: 850.1075, Study Title: Freshwater Fish Toxicity, Rainbow trout ( Oncorhynchus mykiss ) and Bluegi ll sunfish ( Lepomis macrochirus ) are the preferred species. Guideline Number: 850.1075 , Study Title: Estuarine/Marine Fish Acute Toxicity, Sheepshead minnow ( Cyprinodon variegates ) is the preferred species Guideline Number: 850.1300, Study Title: Aquatic Invertebrate Life Cycle Toxicity Daphnid ( Daphnia magna ) is the preferred species. Guideline Number: 850.1350, Study Title: Aquatic Invertebrate Life Cycle Toxicity (estuarine/marine) Mysid shrimp ( Mysidopsis bahia ) is the preferred species.

Guideline Number: 850.1 400

, Study Title: Early Life

- Stage Toxicity Test

, Rainbow

trout ( Oncorhynchus mykiss ) and Bluegill sunfish ( Lepomis macrochirus ) are the preferred species.

Guideline Number: 850.1 400

, Study Title: Early Life

- Stage Toxicity Test

, Sheepshead min now ( Cyprinodon variegates ) is the preferred species.

Guideline Number: 850.1735 , Study Title: Whole Sediment Acute Toxicity invertebrates, freshwater

. Guideline Number: 850.1740, Study Title: Whole Sediment Acute Toxicity invertebrates, marine

. Guideline Number: 850.4400, Study Title: Aquatic Plant Toxicity Test Using Lemna spp., Tier II. Guideline Number: 850.5400, Study Title: Algal Toxicity Test, Tier II

– The four species typically submitted are Pseudokirchneriella subspicata (formerly Selanastrum cap ricornutum ), a freshwater green algae; Anabaena flos

- aquae , a

### 53 freshwater cyanobacterium; Navicula pelliculosa , a freshwater pinnate diatom and

Skeletonema costatum , an estuarine/marine centric diatom.

Table 18 . Available Ecological Effects Data for Terre strial Animals Exposed to DCPA and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? Comments

850.2100 Avian oral toxicity 41155705 Acceptable No * There are questions regarding the health of the birds, in both avian reproduction stu dies and

as a result the studies are classified as Supplemental,

and are considered data gaps.

* *The formulation was not clearly identified in the study; therefore, the TGAI is considered a data gap. However, due to low mortality
(3.2% at 220 g/bee ), t he study is not necessary to call in

at this time. 850.2200 Avian dietary

toxicity 41155706 Acceptable No

41155707 Acceptable

850.2300 Avian reproduction 47550001 Supplemental
Yes * 47550002 Supplemental

850.3020 Honeybee acute

contact to xicity 00018842 Supplemental Yes* *



### Table 19 . Available Ecological Effects Data for Aquatic Animals Exposed to DCPA and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? C omments

850.1075 Freshwater fish

–

Acute toxicity 41054827 Supplemental

Yes Issues with solubility, precipitated out over time, measured samples were not centrifuged. Test system should be flow

through. 41054826 Supplemental

40227001,

TN0908 Supplemental Form. product W

- 75,

limited info rmation

4022 7002,

TN0878 Supplemental Form. product W

- 75, 10% mortality in highest tr eat m ent level

.

00107142,

TN0481 Supplemental Solubility issues

– addition of acetone as solvent apparently increased toxicity of product to fish.

00 1 14686,

TN0711 Supplemental 2 a ctive i ngredient ’s (chlordane & DCPA) ; no information provided on solubility problems

TN0437 Supplemental Concentrations were

not measured

### 54

Guideline Description MRID Classification Data Gap? C omments

00045822 Supplemental Study was only 48h, 30% mortality in highest concentration,

Used Dacthal W

- 75

.

40098001 Invalid Solubility issues with

TGAI

, nominal only,

Solvent concentrations

were not known.

850.1400 Freshwater fish

–

early life stage test No data No data Yes The submission of

studies is needed

.

850.1010 Freshwater invertebrates

–

Acute toxi city 40226901,

TN0933 Supplemental

Yes Issues with solubility of

chemical (TGAI only)

, which is expected with such a low solubility limit in water (0.5 ppm). Definitive EC 50 and NOAEC values

cannot be determined.

Test c oncentrations

were not measured

. 40098001 Supplemental

& Invalid

850.1300 Freshwater invertebrate

–

life cycle test No data No data Yes The submission of

studies is needed

.

850.1075 Saltwater fish

–

Acute toxicity 40228401 Supplemental Yes Issues with solubility of chemical, which i s expected with such a low solubility limit in water (0.5 ppm). Test

concentrations were not measured, and the exchange rate as a

flow

- through study was not provided.

Definitive EC 50 and

NOAEC values cannot

be determined. 850.1025

850.1035

850.1045

85 0.1055 Saltwater invertebrates

–

Acute toxicity 40228401 Supplemental Yes

850.1400 Saltwater fish

–

early life stage test No data No data Yes The submission of

studies is needed

. 850.1350 Saltwater invertebrates

–

life cycle test No data No data Yes

### 55

Table 14 . Available Ecological Effects Data for Plants Exposed to DCPA and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? Comments

850.4100 Terrestrial Plant toxicity:

seedling emergence (Tiers 1 a nd 2) 41564901 Supplemental Yes Test material was not applied to the

maximum labeled rate to determine possible EC values. DCPA was not applied at low enough rates to determine the NOAEC for corn, lettuce, and oat radicle length. An

EC 25 value was calcul ated for the

Tomato data; however, due to the

lack of raw data a NOAEC could not be definitively calculated. It

was recommended that additional studies be conducted following specific guidelines as outlined

below in Appendix D after the study

review in 1 99 2

. Since that time,

new data has not been submitted

, and is still considered a data gap

.

850.4150 Terrestrial Plant toxicity:

vegetative vigor (Tiers 1 and 2) 41440101 Supplemental Yes The percent active ingredient was not specified, the material was not applied to the maximum labeled rate, and only one parameter (fresh weight) was measured and

recorded. It was recommended that

additional studies be conducted following specific guidelines as

outlined below in Appendix D after the study review in 199 2

. Since that time, new data has not been

submitted , and is still considered a data gap

.

850.5400 Aquatic Plant Growth:

algae (Tier 1 & 2 ) 42836102 Invalid

Yes Potential issues (interference) with

the solvent. Test concentrations were not measured, above solubility limit without knowing the actual concentration that test species were exposed to. Test solutions were cloudy white with the presence of a precipitate, and were neither centrifuged nor measured. Tier II

studies are needed to establish

definiti ve EC 50 and NOAEC values.

The submission of new studies is

needed

. 42836103 Invalid

42882401 Invalid

### 56

Guideline Description MRID Classification Data Gap? Comments

850.4400 Aquatic Plant Growth:

vascular plants (Tier 1 & 2 ) 42836101 Invalid Yes Not a sufficient limit test. Potential issues (interference) with the

solvent. Test concentration was not measured, above solubility limit without knowing the actual concentration that test species was exposed to. Test solutions were cloudy white with the presence of a precipitate, and were neither centrifuged nor measured. A Tier II study is needed to establish

definitive EC 50 and NOAEC values.

The submission of new studies is

needed

.



## Other Information Needs

There is specific information that will assist the Agency in refining the ecological risk assessment, incl uding any species

- specific effects determinations. The Agency is very much interested in obtaining the following information:

1. confirmation on the following label information

a. frequency of application, application intervals, and maximum number of applicatio ns per season b. geographic limitations on use

2. use or potential use distribution (e.g., acreage and geographical distribution of relevant crops)

3. use history

4. median and 90 th 

### percentile reported use rates (lbs. a.i./acre) from usage data

– national, state, and county
5. application timing (date of first application and application intervals) by crop

– national, state, and county

6. sub

- county crop location data

7. usage/use information for non

- agricultural uses (e.g., forestry, residential, rights

- of

- way)

8. directly acquir ed county

- level usage data (not derived from state level data)

a. maximum reported use rate (lbs. a.i./acre) from usage data

– county
b. percent crop treated

– county

c. median and 90 th 

### percentile number of applications

– county
d. total pounds per year

– county

e. the y ear the pesticide was last used in the county/sub

- county area
f. the years in which the pesticide was applied in the county/sub

- county area
9. typical interval (days)

10. state or local use restrictions

11. ecological incidents (non

- target plant damage and avian, fish, reptilian, amphibian and mammalian mortalities) not already reported to the Agency

12. monitoring data

### 5 7

13. the amount of dioxin s/furans, and HCB present in technical DCPA.

The analysis plan will be revisited and may be revised depending upon the data available i n the open literature and the information submitted by the public in response to the opening of the Registration review docket.



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### 62

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- scale, field

- based evaluation of the biota

sediment

- accumulation factor model. Environmental Science and Technology , 35, 1709

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MRID Environmental Fate Bibliography

MRID

Number Study Citation

00 114648 Szalkowski, M. (1975) The Effect of Light, Temperature, and pH on the Hydrolysis of

Dacthal. (Unpublished study rec eived Mar 23, 1976 under 3F1417; submitted by Diamond Shamrock Chemical Co., Cleveland, OH; CDL:095189

- D)

00 114649 Duane, W. (1976) Aerobic Soil Metabolism of Dacthal. (Unpublished study received Mar 23,

1976 under 3F1417; submitted by Diamond Shamrock Ch emical Co., Cleveland, OH;

CDL:095189

- F)

00 114651 Duane, W. (1976) Anaerobic Soil Metabolism of Dacthal. (Unpublished study received Mar

23, 1976 under 3F1417; submitted by Diamond Shamrock Chemical Co., Cleveland, OH;

CDL:095189

- H)

00 114652 Duane, W. (1 976) The Effect of Steam Sterilization on the Metabolism of Dacthal in Soils.

(Unpublished study received Mar 23, 1976 under 3F1417; submitted by Diamond Shamrock Chemical Co., Cleveland, OH; CDL:095189

- I)

00 143063 Szalkowski, M. (1976) Photohydrolysis of Dacthal. Unpublished study prepared by Diamond

Shamrock Corp. 10 p.

41155715 Szalkowski, M.; Marciniszyn, J.; Killeen, J. (1981) Accumulation, Distribution and

Depuration of Carbon 14

- Residues of Dacthal ( DS

- 893) in Channel Catfish ( Ictalurus

punctatus ) Under Static Aquatic Conditions: Document No. 139

- 4EI

- 81

- 0015

- 002. Unpublished study prepared by Analytical Bio Chemistry Laboratories, Inc. 76 p.

41155716 Szalkowski, M.; Stallard, D.; Killeen, J. (1980) Accumulation, Distribution and Depuration of

Carbo n 14

- Dacthal (DS

- 893) in Bluegill Sunfish ( Lepomis macrochirus ) under Flow Through Aquatic Conditions: Document No. 141

- 3EI

- 79

- 0138

- 001. Unpublished study prepared by Analytical Bio Chemistry Laboratories, Inc. 40 p.

### 63

41197601 Szalkowski, M.; Marciniszyn, J.; Killen, J. (1981) Characterization and Quantitation of

(Carbon

- 14) in Water, Soil and Fish Exposed to (Carbon

- 14)

- Dimethyl 2,3,5,6

- Tetrachloroterephthalate (Dacthal, DS

- 893) in a Static Aquatic System: Document No. 140

- 4EI

- 81

- 0018

- 002. Unpublished st udy prepared by Analytical Bio Chemistry Laboratories, Inc. 102 p.

41197602 Szalkowski, M.; Marciniszyn, J.;Killeen, J. (1981) Characterization and Quantitation of

(Carbon

- 14)

- Residues in Water and Fish Exposed to (Carbon

- 14)

- dimethyl 2,3,5,6

- Tetrachlorot erephthalate (Dacthal, DS

- 893) in a Flow Through Aquatic System: Document

No. 142

- 4EI

- 81

- 0017

- 002. Unpublished study prepared by Analytical Bio

- Chemistry Laboratories, Inc. 80 p.

41508607 Korsch, B. (1990) A Photolysis Study of Carbon 14

- Dimethyl Tetra

- c hloroterephthalate in

Water: Lab Project Number: 89

- 0366: 3496

- 89

- 0366

- EF

- 001: SDS

- 893. Unpublished study prepared by Ricerca, Inc. 119 p.

41508608 Korsch, B. (1990) A Photolysis Study of Carbon 14

- Dimethyl Tetra

- chloroterephthalate on

Soil: Lab Project Number: 89

- 0365: 3495

- 89

- 0365

- EF

- 001: SDS

- 893. Unpublished study prepared by Ricerca, Inc. 115 p.

41508609 Formanik, J. (1989) Determination of Residues of DCPA, Its Soil Metabolites and HCB from

Soil Dissipation Studies near Gilroy, CA. 1987

- 1988: Lab Project Number: 1537

- 88

- 0066:

1537

- 88

- 0066

- CR

- 001. Unpublished study prepared by Ricerca, Inc. 477 p.

41508610 Formanik, J. (1990) Determination of Residues of DCPA, its Soil Metabolites and HCB from

Soil Dissipation Studies near Greenfield, CA: 1987

- 198 8: Lab Project Number: 1537

- 88

- 0066: 1537

- 88

- 0066

- CR

- 002. Unpublished study prepared by Ricerca, Inc. 462 p.

41648801 Doran, T. (1990) Response to EPA Review: Aerobic Soil Metabolism of Dacthal: Lab Project

Number: 000/3EF/76/2083/001. Unpublished Study prepared by Ricerca, Inc. 76 p.

41648802 Doran, T. (1990) Response to EPA Review: Anaerobic Soil Metabolism of Dacthal: Lab

Project Number: 000/3EF/76/2082/001. Unpublished study prepared by Ricerca, Inc. 40 p.

41648803 Korsch, B. (1988) Adsorption and D esorption of Dimethyl Tetra

- chloroterephthalate to Soils:

Lab Project Number: 1701/87/0099/ EF/001/001. Unpublished study prepared by Ricerca, Inc. 64 p.

41648804 Korsch, B.; Kapostasy, W. (1990) Adsorption and Desorption of Mono

- methyl

Tetrachloroterep hthalate to Soils: Lab Project Number: 1736/88/0005/EF/001. Unpublished study prepared by Ricerca, Inc. 8 p.

41648805 Korsch, B.; Kapostasy, W. (1989) Adsorption and Desorption of Tetrachloroterephthalic Acid

to Soils: Lab Project Number: 1735/ 88/0004/EF /001. Unpublished study prepared by Ricerca, Inc. 64 p.

42262602 Korsch, B.; Waller, R. (1992) Adsorption and Desorption of Dimethyl

Tetrachloroterephthalate to Soils: Amendment II: Lab Project Number: 1701

- 87

- 0099

- EF

001. Unpublished study prepared by Ri cerca, Inc. 192 p.

43661101 Shelby, D. (1995) Adsorption and Desorption of Dimethyl Tetrachloroterephthalate (DCPA)

to Soil: Lab Project Number: 5971

- 94

- 0018

- EF

- 001. Unpublished study prepared by Ricerca, Inc. 123 p.



### 078701 DCPA Eco Effects Bibliography

71

- 1 Avian Single Dose Oral Toxicity

MRID Citation Reference

83574 DeWitt, J.B. (1962) Toxicity of Pesticides to Upland Birds and

Waterfowl. ( U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Section of Chemical and Physiolo gical Studies; unpublished study; CDL:090443

- J)

114657 Dewitt, J. (1961) Toxicity of Pesti cides to Upland Birds and Water fowl:

### 64 Dacthal. ( U.S. Fish and Wildlife Service, Branch of Wildlife Resear ch; unpublished study; CDL:095363

- E)

41155705 Shults, S.; Roblin, M.; Killeen, J. (1989) Acute Oral Toxicity (LD 50)

Study in Bobwhite Quail with Technical DCPA: Project ID 230

- 112. Unpublished study prepared by Wildlife International Ltd. 61 p.



### 71

- 2 Avian Dietary Toxicity

MRID Citation Reference

31877 DeWitt, J.B. (1963) Toxicity of Dacthal (Dimethyl ester of Tetra

chloroterephthalic acid). (Unpublished study received Sep 27, 1974

under 677

- 318; prepared by U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, submitted by Diamond S hamrock Agricultural Chemicals, Cleveland, Ohio; CDL:009849

- M)

69191 DeWitt, J.B.; Stickel, W.H.; Spri nger, P.F. (1963) Wildlife Stud ies,

Patuxent Wildlife Research Center, 1961

- 1962. Pages 74

- 75, 90, In

Pesticide Wildlife Studies: A Review of Fish and W ildlife Service Investigations during 1961 and 1962

. By U.S. Fish and Wildlife Service, Branch of Wildlife Research. Washington, D.C.: USFWS. (Circular 167; published study; CDL:230691

- G)

70082 DeWitt, J.B. (1961) Toxicity of Pesticides to Upland Birds a nd

Waterfowl. Progress rept., period ending Dec 31, 1966. (U.S. Fish and Wildlife Service, Branch of Wildlife Research, Section of Chemical and Physiological Studies; unpublished study; CDL: 093786

- D)

70083 DeWitt, J.B. (1962) Toxicity of Pesticides to U pland Birds and

Waterfowl. Progress rept., period ending Jun 30, 1962. (U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Section of Chemical and Physiological Studies; unpublished study; CDL:093786

- E)

70084 DeWitt, J.B. (1963) Letter se nt to L. Gordon Utter dated Nov 7, 1963 ?

Toxicity of Dacthal to upland birds and waterfowl|. ( U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Section of Chemical and Physiological Studies; CDL: 093786

- F)

103762 Uniroyal Chemical (1963) Toxicity Tests of Selected Chemicals at

Patuxent, 1963. (Unpublished study received Aug 20, 1974 under 400

- 41; CDL:130997

- B)

41155706 Shults, S.; Roblin, M.; Killeen, J. (1989) Dietary (LC50) Study in

Bobwhite Quail with Technical DCPA: Project ID 230

- 1 10 and 89

- 0018. Unpublished study prepared by Wildlife International Ltd. in association with Ricerca, Inc. 113 p.

41155707 Shults, S.; Roblin, M.; Killeen, J. (1989) Dietary (LC50) Study in Mallard

Ducks with Technical DCPA: Project IDs 230

- 111 and 89

- 0017. Unpublished study prepared by Wildlife International, Ltd. in association with Ricerca, Inc. 114 p.

31876 DeWitt, J.B. (1961) Toxicity of Dacthal. (Unpublished study re ceived

Sep 27, 1974 under 677

- 318; prepared by U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center

, submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:009849

- L)

### 65

71

- 4 Avian Reproduction

MRID Citation Reference

69191 DeWitt, J.B.; Stickel, W.H.; Sprin ger, P.F. (1963) Wildlife Stud ies,

Patuxent Wildlife Research Center, 1961

- 1962. Pages 74

- 75, 90, In

Pesticide Wildlife Studies: A Review of Fish and Wildlife Service Investigations during 1961 and 1962. By U.S. Fish and Wildlife Service, Branch of Wildlife Research. Washington, D.C.: USFW S. (Circular 167; published study; CDL:230691

- G)

47550001 Frey, L.; Martin, K.; Beavers, J.; et al. (2003) Chlorthal

- Dimethyl

(DCPA): A Reproduction Study with the Northern Bobwhite: Final Report. Project Number: 246/115, 246/1/16, 246/020802/QR/SUB246. Unpublished study prepared by Wildlife International Ltd. 187 p.

47550002 Frey, L.; Martin, K.; Beavers, J.; et al. (2003) Chlorthal

- Dimethyl

(DCPA): A Reproduction Study with the Mallard: Final Report. Project Number: 246/116, 246/020802/MR/SUB246. Unpub lished study prepared by Wildlife International, Ltd. 179 p.



### 72

- 1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

68507 Hughes, J.S.; Davis, J.T. (1964?) Effects of Selected Herbicides on

Bluegill Sunfish. (Louisiana, Wild Life and Fisheries Commission; unpublished study; CDL:231131

- A)

70085 Takematsu, T. (19??) Undated letter sent to L. Gordon Utter Tox icity of

Dacthal to fish|. (Unpublished study received Jun 29, 1973 under 3F1417; prepared by Utsunomiya Univ., Japan, submitted b y Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:093786

- H)

70086 Diamond Shamrock Agricultural Chemicals (19??) Effects of Dacthal on

Marine Organisms. (Unpublished study received Jun 29, 1973 under 3F1417; CDL:093786

- I)

107142 McCann, J . (1972) Dacthal G

- 2.5 Herbicide: Rainbow Trout (Salmo

gairdneri) : Test No. 481. (U.S. Agricultural Research Service, Pesticides Regulation Div., A nimal Biology Laboratory; unpub lished study;
CDL:130357

- A)

Static Jar Test # 437. Unpub lished study prepar ed by Animal Biology Laboratory. 3 p.

114658 Takematsu (1963) Letter sent to L. Utter dated 1963 (Dacthal toxicity to

carp). (Unpublished study received on unknown date under 6E1711; prepared by Utsunomiya Univ., Japan, submitted by In terregional

Research Project No. 4, New Brunswick, NJ; CDL: 095363

- H)

114686 Pitcher, F. (1974) Corenco One Twenty Three: Rainbow Trout|: Test No.

711. (U.S. Environmental Protection Agency, Pesticides Regulation Div., Animal Biology Laboratory; unpublished study; CDL:13239 0

- A)

40227001 McCann, J. (1975) Diamond Chemical Dacthal W

- 75 Herbicide: Toxicity

### 66 to Rainbow Trout (Salmo gairdneri): Static Jar Test #908. Un

- published study prepared by Animal Biology Laboratory. 3 p.

40227002 McCann, J. (1975) Diamond Chemical Dact hal W

- 75 Herbicide: Toxicity

to Bluegill (Lepomis macrochirus): Static Jar Test #878. Unpublished study prepared by Animal Biology Laboratory. 3 p.

40098001 Mayer, F.; Ellersieck, M. (1986) Manual of Acute Toxicity: Interpretation

and Data Base for 410 C hemicals and 66 Species of Freshwater Animals. US Fish & Wildlife Service, Resource Publication 160. 579 p.

41054826 Shults, S.; Wilson, N. (1989) Static, Acute Toxicity (LC50) Study in

Rainbow Trout with Technical DCPA (Dimethyl 2,3,5,6

- Tetra

chlorotere phthalate): Doc. No. 690

- 5TX

- 84

- 0046

- 002. Unpublished study prepared by SDS Biotech Corp. 64 p.

41054827 Shults, S.; Wilson, N. (1985) Static, Acute Toxicity (LC50) Study in

Bluegill with Technical DCPA (Dimethyl 2,3,5,6

- Tetrachloro

terephthalate): Doc. No. 690

- 5TX

- 84

- 0047

- 002. Unpublished study prepared by SDS Biotech Corp. 64 p.

45822 McCann, J.A. (1969) Diamond Chemical Dacthal W

- 75 Herbicide:

Toxicity to Bluegill, Lepomis macrochirus . (U.S. Agricultural Research Service, Pesticides Regulation Div., Animal Biology Laboratory, unpublished study; CDL:109530

- A)

18644 Toa Agricultural Chemical Company, Limited (1962) Test on Fish

Toxicity of C

- 1936, C

- 1983, an d C

- 2059. (Unpublished study re ceived Oct 8, 1964 under 100

- 548; submitted by Ciba

- Geigy Corp.

, Greensboro, N.C.; CDL:023178

- K)

19161 Toa Agricultural Chemical Company, Limited (1962) Test on Fish

Tox icity of C

- 1936, C

- 1983, and C

- 2059. (Unpublished study re ceived Oct 8, 1964 under 100

- 549; submitted by Ciba

- Geigy Corp., Greensboro, N.C.; CDL:007 070

- Q)

31878 Kodama, J.K. (1960) Subacute Fish Toxicity

- Bluegills and Goldfish.

(Unpublished study including letter dated Dec 10, 1963 from Ta

kematsu to L. Gordon Utter, received Sep 27, 1974 under 677

- 318; prepared by Hazleton Laboratories, Inc., subm itted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:009849

- N)



### 72

- 2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

40103302 Shults, S. (1985) Static, Acute Toxicity (EC50) Study in Daphnia with

Technical DCPA: Laboratory ID: 690

- 5TX

- 84

- 0048

- 02. Unpublished study prepared by SDS Biotech Corp. 70 p.

40226901 McCann, J. (1976) Diamond Chemical Dacthal W

- 75 Herbicide: Toxicity

to Daphnia magna: Static Jar Test #933. Unpublished study pre

- pared by Animal Bi ology Laboratory. 3 p.

40098001 Mayer, F.; Ellersieck, M. (1986) Manual of Acute Toxicity: Inter

pretation and Data Base for 410 Chemicals and 66 Species of Freshwater Animals. US Fish & Wildlife Service, Resource Pub

- lication

### 67 160. 579 p.

41054828 Shu lts, S.; Wilson, N. (1985) Static, Acute Toxicity (EC50) Study in

Daphnia with Technical DCPA (Dimethyl 2,3,5,6

- Tetrachloroter

ephthalate): Doc. No. 690

- 5TX

- 84

- 0048

- 002. Unpublished study prepared by SDS Biotech Corp. 63 p.



### 72

- 3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation Reference

114659 U.S. Fish and Wildlife Service (19??) Effects of Dacthal on Marine

Organisms. (Bureau of Commerci al Fisheries, Biological Laboratory

Sabine Island ; unpublished study; CDL:095363

- I)

31879 Lo we, J.I. (1964) Effects of Dacthal on Marine Organisms. (Unpub

lished study received Sep 27, 1974 under 677

- 318; prepared by U.S. Fish and Wildlife Service, Bureau of Commercial Fisheries, Biological Laboratory, submitted by Diamond Shamrock Agricultur

- a l Chemicals, Cleveland, Ohio; CDL:009849

- O)

40228401 1986, USEPA Gulfbreeze Laboratory Acute testing summaries

Brown shrimp, Sheepshead minnow, Eastern oyster

38448 Butler, P.A. (1963) Co mmercial Fishery Investigations. U.S. Fish and

Wildlife Service, Div. of Biological Research, Bureau of Commercial Fisheries. (Circular 199; published study; CDL: 091902

- B)



### 122

- 2 Aquatic plant growth

MRID Citation Reference

41054829 Shults, S.; Wilson, N. (1985) Algal Growth Inhibition Study in Sce

nede smus subspicatus with Technical DCPA (Dimethyl 2,3,5,6

- Tet

rachloroterephthalate): Doc. No. 688

- 5TX

- 84

- 0049

- 002. Unpub

- lished study prepared by SDS Biotech Corp. 54 p.

42836101 Hughes, J.; Balcom, P. (1993) The Toxicity of DCPA Technical to

Lemna gibba G3: Lab Project Number: B038

- 033

- 4. Unpublished study prepared by Malcolm Pirnie, Inc. 23 p.

42836102 Hughes, J.; Balcom, P. (1993) The Toxicity of DCPA Technical to

Anabaena flos

- aquae: Lab Project Number: B038

- 033

- 1. Unpublished study prepared by Malc olm Pirnie, Inc. 24 p.

42836103 Hughes, J.; Balcom, P. (1993) The Toxicity of DCPA Technical to

Skeletonema costatum: Lab Project Number: B038

- 033

- 3. Unpublished study prepared by Malcolm Pirnie, Inc. 24 p.

42882401 Hughes, J.; Balcom, P.; Alexander, M . (1993) The Toxicity of DCPA

Technical to Navicula pelliculosa: Lab Project Number: B038

- 033

- 2. Unpublished study prepared by Malcolm Pirnie, Inc. 25 p.

### 68

123

- 1 Seed germination/seedling emergence and vegetative vigor

MRID Citation Reference

41440101 Backus, P.; Crosby, K.; Schollenberger, (1990) Effect of DCPA on

Vegetative Vigor of Plants (Tier 2): Lab Project No: 89

- 0128. Unpublished study prepared by Ricerca, Inc. 29 p.

41564901 Backus, P.; Crosby, K. (1990) Effect of DCPA on Seed Germi nation/

Seedling Emergence (Tier 2): Lab Project Number: 89

- 0129: 3322

- 89

- 0129

- BE

- 001. Unpublished study prepared by Ricerca, Inc. 193.



### 123

- 2 Aquatic plant growth

MRID Citation Reference

41155714 Hughes, J. (1989) The Toxicity of DCPA (Dact hal/Dimethyl Tetrachlo

roterephthalate) to Selenastrum capricornutum: Project ID 1401

- 01

- 1100

- 1. Unpublished study prepared by Malcolm Pirnie, Inc. 26 p.



### 141

- 1 Honeybee Acute Toxicity

75129 Anderson, L.D.; Atkins, E.L., Jr. (1960) Pesticides Hazardous to

Honeybees. : Univ. of California, Agricultural Extens ion Service. (OSA # 72; also In unpublished submission received Dec 5, 1960 under 271

- 14; submitted by International Minerals & Chemical Corp., Terre Haute, Ind.; CDL:231122

- B)

9181 or

18842 Atkin s, E.L., Jr.; Anderson, L.D.; Greywood, E.A. (1969) Effect of

Pesticides on Apiculture: Project No. 1499. (Unpublished study received Jul 29, 1976 under 352

- 342; prepared by Univ. of California

- Riverside, Dept. of Entomology, submitted by E.I. du Pont de N emours & Co., Wilmington, Del.; CDL:224800

- C)



### NON Guideline Selections

29844 Klingman, G.C.; Freeman, J.F .; Ahrens, J.F.; et al. (1962) Toxici ty of

Herbicides to Various Crops and Residues of Diphenamid and Other Chemicals in Soils|: Experiment No. GLP2

- 62. (Unpublished study including experiment nos. M2

- 5, M2

- 6, C2

- 26...; received Nov 1, 1962 under unknown admin. no.; prepared in cooperation with North Carolina State College and others, submitted by Elanco Products Co., Div. of Eli Lilly and Co., Indiana polis, Ind., CDL:120175

- C)

30128 Jensen, H.L.; Petersen, H.I. (1952) Detoxication of hormone herbi

cides by soil bacteria. Nature 170(4314):39

- 40. (Also In un

- published study received Jan 2, 1980 under 2217

- 641; submitted by PBI

- Gordon Corp., Kansas Cit y, Kans.; CDL:241574

- Z)

47164601 Moore, D.; Breton, R.; Rodney, S.; et al. (2007) Generic Problem

Formulation for California Red

- Legged Frog. Project Number: 89320, 05232007. Unpublished study prepared by Cantox Environmental Inc. 87 p.

47164602 Holmes, C.; Vamshi, R. (2007) Data and Methodology Used for Spatial

### 69 Analysis of California Red Legged Frog Observations and Proximate Land Cover Characteristics. Project Number: 3152007, WEI/252/03. Unpublished study prepared by Waterborne Environmental, Inc. (WE I). 19 p.

27401 Christensen, C.; Rogers, W.; Colbert, F.; et al. (1976) Sward^(TM)I 50W

for Preemergence Control of Annual Grasses and Some Broad

- leaf Weeds in Mature Turfgrasses. (Unpublished study received Aug 12,

1976 under 1471

- 106; prepared in coope ration with Univ. of Florida, submitted by Elanco Products Co., Div. of Eli Lilly and Co., Indianapolis, Ind.; CDL:224918

- A)

114641 Diamond Alkali Co. (1963) Abstracts of Reports of Investigations Made

with Respect to the Safety of the Pesticide Chemical , Dac thal. (Compilation; unpublished study received Jan 9, 1968 un der 8F0640;
CDL:091112

- A)

### 70

Appendix A

. Maximum DCPA use rates and management pra ctices by crop based on current

labels.

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

NON

- FOOD/NON

- FEED USES

golf course turf 15 lb A FlC NS NS NS Sprayer //Broadcast (a)

nursery stock 12 lb A WP NS NS NS Aircraft/ Sprayer/ Sprinkler irrigation //Soil treatment (a)

ornamental and/or shade

trees 9 lb A G NS NS NS Spreader

//Soil trea tment (a)

.2410 lb 1K sq.ft

*C2 G NS NS NS Not on label //Soil treatment (b)

2.609E

- 04 lb sq.ft

*C2 G NS NS NS Spreader //Soil treatment (c)

ornamental ground cover 2.609E

- 04 lb s q.ft

*C2 G NS NS NS Spreader //Soil treatment (a)

ornamental herbaceous plants 9 lb A G NS NS NS Spreader //Soil treatment (a)

.2410 lb 1K sq.ft

*C2 G NS NS NS Not on label //Soil treatment (b)

2.609E

- 04 lb sq.ft

*C2 G NS NS NS Spreader //Soil treatment (c)

ornamental lawns and turf 15 lb A FlC

G NS NS NS Sprayer/ Spreader

//Broadcast/ Soil broadcast treatment (a)

.3500 lb 1K sq.ft

*C2 G NS NS NS Spreader //Soil broadcast treatment (b)

ornamental nonflowering plants 9 lb A G NS NS NS Spreader //Soil treatment (a)

.2410 lb 1K sq. ft

*C2 G NS NS NS Not on label //Soil treatment (b)

2.609E

- 04 lb sq.ft

*C2 G NS NS NS Spreader //Soil treatment (c)

ornamental sod farm (turf) 15 lb A FlC NS NS NS Sprayer //Broadcast (a)

ornamental woody shrubs

and vines 9 lb A G NS NS NS Spreader //Soil treatment (a)

.2410 lb 1K sq.ft

*C2 G NS NS NS Not on label //Soil treatment (b)

2.609E

- 04 lb sq.ft

*C2 G NS NS NS Spreader //Soil treatment (c)

recreation area lawns 15 lb A FlC NS NS NS Sprayer //Broadcast (a)

residential lawns .3500 lb 1K sq.ft

*K1 G NS NS N S Spreader //Soil broadcast treatment (a)

### 71

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

FOOD/FEED USES

arrowroot 10.5 lb A G

WP NS NS NS Aircraft/ Ground/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil treatment (a)

beans, dried

- type 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label //Soil treatment (b)

beans, succulent (snap) 10.35 l b A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label //Soil treatment (b)

2.078E

- 04 lb sq.ft

*A1 G NS NS NS Spreader //Soil treatment (c)

brassica (head and stem) vegetables 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ S oil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

broccoli 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigati on/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

2.078E

- 04 lb sq.ft

*A1 G NS NS NS Spreader //Soil treatment (c)

broccoli raab 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

tre atment/ Soil broadcast treatment/

Soil incorporated treatment/ Soil treatment (a)

brussels sprouts 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

### 72

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

cabbage 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410 E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

2.078E

- 04 lb sq.ft

*A1 G NS NS NS Spreader //Soil treatment (c)

cabbage, chinese 10.5 lb A WP NS NS NS Aircraft/ S oil incorporation equipment/ Sprayer/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment (a)

canola \ rape 10.5 lb A WP NS NS NS Aircraft/ Soil incorporation equi pment/ Sprayer/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment (a)

cauliflower 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipmen t/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

2.078E

- 04 lb sq.ft

*A1 G NS NS NS Spreader //Soil treatment (c)

chayote 10.5 lb A G

WP NS NS NS Aircraft/ Ground/ Shaker can/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

collards 10.5 lb A FlC

G NS NS NS Aircraft/ Ground/ Soil incorporation equipment/

### 73

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

WP Sprayer/ Spreader/ Spri nkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

cucumber 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

eggplant 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

garlic 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

gherkin 10.5 lb A G

WP NS NS NS Aircraft/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

ginseng (medicinal) 10.5~ lb A WP NS NS NS Sprayer //Soil broadcast treatment (a)

gourd (wax), chinese 10.5 lb A G

WP NS NS NS Aircraft/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil treatment (a)

gourds 10.5 lb A G

WP NS NS NS Aircraft/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

groundcherry (strawbe rry tomato/tomatillo) 10.5 lb A G

WP NS NS NS Aircraft/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

hanover salad 10.5 lb A FlC NS NS NS Aircraft / Ground/ Soil

### 74

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

G

WP incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

horseradish 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

kale 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2 .410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

lettuce, head 10.21 lb A WP 1/cc NS NS Sprayer //Spray (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

lettuce, leaf (black seeded simpson, salad bowl, etc.) 10.21 lb A WP 1/cc NS NS Sprayer //Spray (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label

//Soil treatment (b)

manioc (cassava) 10.5 lb A G

WP NS NS NS Aircraft/ Ground/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

melons 10.21 lb A WP NS NS NS Sprayer //Spray (a)

melons, bitter (balsam pear) 10.5 lb A G NS NS NS Spreader //Soil treatment (a)

melons, cantaloupe 10.5 lb A FlC NS NS NS Aircraft/ Ground/ Soil incorporation equipment/

S prinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

melons, honeydew 10.5 lb A FlC NS NS NS Aircraft / Ground/ Soil

### 75

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

incorporation equipment/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

melons, musk 10.5 lb A G

WP NS NS NS Aircraft/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

melons, water 10.5 lb A FlCG

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

momordica spp. 10.5 lb A G

WP NS NS NS Aircraft/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broa dcast treatment/ Soil treatment (a)

.2406 lb 1K sq.ft

*A1 G NS NS NS Shaker can //Soil treatment (b)

mustard 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Sp reader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label

//Soil tr eatment (b)

onion 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

2.078E

- 04 lb sq.ft

*A1 G NS NS NS Spreader //Soil treatment (c)

onions (green) 10.5 lb A FlC NS NS NS Aircraft/ Ground/ Soil

### 76

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

G

WP incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

onions (scallions) 10.5 lb A FlC

G NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

peas, southern 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label //Soil treatment (b)

pepino (melon pear) 10.5 lb A G

WP NS NS NS Aircraft/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation / Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

pepper 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label

//Soil treatmen t (b)

potato, white/irish 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label //Soil treatment (b)

radish 10.5 lb A FlC

WP NS NS NS Soil incorporation equipment/ Sprayer/ Sprinkler irrigation //Chemigation/ Soil band treatment (a)

shallot 10.5 lb A G NS NS NS Spreader //Soil treatment (a)

squash (all or unspecified) 10.21 lb A WP NS NS NS Sprayer //Spray (a)

squash (summer) 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

squash (winter) (hubb ard) 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

2.410E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (b)

strawberry 10.5 lb A G NS NS NS Spreader //Soil treatment (a)

2.078E

- 04 lb sq.ft G NS NS NS Spreader

### 77

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

*A1 //Soil treatment (b)

2.008E

- 04 lb sq.ft

*A1 G NS NS NS Not on label //Soil treatment (c)

sweet potato 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

2.078E

- 04 lb sq.ft

*A 1 G NS NS NS Spreader //Soil treatment (b)

taro 10.5 lb A G

WP NS NS NS Aircraft/ Ground/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil treatment (a)

tomatillo 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

tomato 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

2.4 10E

- 04 lb sq.ft

*A2 G NS NS NS Not on label //Soil treatment (b)

2.078E

- 04 lb sq.ft

*A1 G NS NS NS Spreader //Soil treatment (c)

turmeric 10.5 lb A G

WP NS NS NS Aircraft/ Groun d/ Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast treatment/ Soil treatment (a)

turnip (greens) 10.5 lb A FlC

G

WP NS NS NS Aircraft/ Ground/ Soil incorporation equipment/ Sprayer/ Spr eader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil incorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label

//Soil tre atment (b)

turnip (root) 10.5 lb A FlC

G NS NS NS Aircraft/ Ground/ Soil incorporation equipment/

### 78

Use Site Ma x. Rate per App Max. Rate

Unit/Area

*UG Form Max.# Apps cc & yr Max. App

Rate/ cc & yr Min. App

Interval (days) Application Equipment

//Type (Reg # Code)

WP Sprayer/ Spreader/ Sprinkler irrigation //Chemigation/ Soil band

treatment/ Soil broadcast

treatment/ Soil

i ncorporated treatment/ Soil treatment (a)

2.410E

- 04 lb sq.ft

*A2 G NS NS NS Not on label //Soil treatment (b)

yam 10.35 lb A G NS NS NS Spreader //Soil treatment (a)

### 79

Appendix B

. Output generated by SIP v.1.0
Table 1. Inputs

Parameter Value

Chemical name DCPA
Solubility (in water at 25 o C; mg/L) 0.5

Mammalian LD 50 (mg/kg

- bw) 5000 Mammalian test species laboratory rat Body weight (g ) of "other" mammalian species

Mammalian NOAEL (mg/kg

- bw) 1000 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg

- bw) 2250 Avian test species northern bobwhite quail
Body weight (g) of "other" avian species Mineau scaling factor 1.15

Mallard NOAEC (mg/kg

- diet) 0 Bobwhite quail NOAEC (mg/kg

- diet) 0 NOAEC (mg/kg

- diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg

- di et) for 2nd other bird species Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic Upper bound exposure (mg/kg

- bw) 0.0860 0.0860 Adjusted toxicity value (mg/kg

- bw) 3845.8028 769.1606

Ratio of exposure to toxicity 0.0000 0.0001

Conclusion* Drinking water exposure alone is NOT a potential
concern for mammals Drinking water exposure alone is NOT a potential
concern for mammals

Table 3. Avian Results

Parameter Acute Chronic
Upper bound exposure (mg/kg

- bw) 0.4050 0.4050 Adjusted toxicity value (mg/kg

- bw) 1620.9664 0.0000 Ratio of exposure to acute toxicity 0.0002 0.0000

Conclusion* Drinking water exposure alone is NOT a potential
concern for birds Due to insufficient data, risk

c annot be precluded

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non

- target animals.

### 80

Appendix C : Additional Information for DCI Rationale

Environmental Fate

Ecological Effects Fish, Aquatic Invertebrates and Aquatic Plants: Previou sly submitted DCPA TGAI toxicity

data for freshwater and estuarine/marine fish, aquatic invertebrates and aquatic plants (vascular

and non

- vascular) are not acceptable, as there were issues with the solubility of the technical grade compound. The solubili ty of the DCPA is an issue that was not properly examined in the previously submitted studies for fish, aquatic invertebrates, and aquatic plants . Without measurement or centrifugation of the water samples, especially in the presence of precipitates,

the actual dissolved soluble concentration the test organisms were exposed to is not known. The actual soluble, dissolved concentrations are likely lower than the nominal concentrations, resulting in a potential underestimation of risk to aquatic species. Th erefore, new TGAI acute and chronic toxicity data are required for fish, aquatic invertebrates, and aquatic plants for

DCPA.

No toxicity data are currently available to assess the risk of the DCPA degradate TPA to freshwater and estuarine/marine fish, aq uatic invertebrates , and aquatic plants (vascular and non

vascular) . Given the structural similarity between the parent chemical and the major degradate, the degradate may retain the toxicological properties of the parent. In addition, TPA is mobile

and persistent , and has been d etected in ground/surface water. Therefore, both acute and chronic toxicity data is needed to evaluate the risk potential resulting from the degradation of DCPA to TPA in the aquatic environment.

The log K

ow 

### of DCPA is 4.28

- 4.40 and therefore, as the log K

ow 

### is greater than 3 for the parent DCPA, the data requirement of both freshwater and marine whole sediment acute toxicity data was triggered. As a cute sediment toxicity data for neither freshwater n or marine organisms were

ever submitted to the Agency, this data requirement is considered a data gap. In addition, both fish and oyster BCF studies indicate that DCPA bioaccumulates in both test organisms. Thus indicating that bioaccumulation may be a potentially important path way in aquatic organisms. In the fish BCF study a trace amount of the MTP degradate was observed in both fish viscera and whole fish tissue, with the greatest amount accumulating on day 14 of 30.

Although there is limited information regarding the log K
ow 

### for the two the major degradates of DCPA, e stimated values using d ata from EPI Suite version 3.20 (which us ed the SMILES string

from Table 2 as input ) determined values for TPA and MTP. F or TPA the log K

ow 

### was 2.13 and the log K

ow 

### for MTP was 3.19, respectively. From this information, it can be understood that

there is the potential for bioaccumulation in both organisms and the environment . Due to the significant amount of TPA reported in the environment via monitoring data, both BCF and sediment toxicity studies are needed to better characterize the risk to non

- target organisms resulting from use of DCPA. Therefore, whole sediment toxicity for the parent DCPA, and bioaccumulation (BCF) and whole sediment (b oth acute and chronic) toxicity studies for the two major degradates

, are needed to better characterize risk to non

- target aquatic organisms.

### 81

Birds: An acute avian inhalation toxicity test is being requested using the bobwhite quail, the species that wa s tested in the acute oral studies. The study being requested will aid in evaluating this pathway of concern for avian taxa. An avian inhalation study protocol must be submitted for review and approval by the Agency prior to initiation of this study. If i nhalation acute toxicity data are not submitted for birds, then risk to birds from acute inhalation exposure to DCPA will be presumed.

It is likely that, for most pesticide use patterns, passerines are more likely to be exposed to pesticides than upland game species and waterfowl. Because passerine species have higher metabolic rates due to their smaller sizes than either waterfowl or upland game bird species and because they may utilize different metabolic pathways, they may be more or less sensitive t o DCPA. In order to properly characterize risk to passerines, an avian oral toxicity test is required for passerine birds. A passerine study protocol must be submitted for review by the Agency prior to initiation of the study.

Terrestrial Plants : The t oxicity studies that were submitted did not provide enough information to definitively estimate the toxicity of DCPA to terrestrial plants. Both s eedling emergence and vegetative vigor test s should be conducted for a minimum of 28 days to accommodate the delayed mode of action ( mitotic disruption ) of DCPA. In mitotic disruption, the chemical first will stop the growth of roots and shoots of seedlings. Then after a period of time it causes deterioration. This delay may be several weeks depending on envir onmenta l conditions and species tested, and the species that were tested originally were considered tolerant species, and others need to be used in subsequent studies.

The following information should be required from each replicate of the seedling emer gence

tests: Percentage of emergence and survival of seedlings every seven days;

Height of shoots every seven days; and Fresh weights and dry weights of shoots at study termination

The following information should be required from each replicate of the v egetative vigor tests:

Plant height every seven days Phytotoxicity rating every seven days; and Fresh weight of foliage, dried weight of foliage, fresh weight of roots, dried weight of

roots at test termination.