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



### March 12, 2014 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### PC Codes: 019201, 019202

MEMORANDUM DP Barcode: 414994

SUBJECT: Registration Review; Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and Human Health Drinking Water Exposure Assessments for MCPB



### FROM: Hannah Yingling, Biologist -1JJ-

# ~ (,

# '3~r~N Larry Liu, Environmental Scientist,

### Ph**~~.,-** 

# ...J? (/\-/

Environmental Risk Branch V Environmental Fate and Effects Division (7507P) •



### THROUGH: Mah Shamim, Branch Chief, Ph.D. 

# A/l.dP...h

# !~ ..3/!2- 

# /If

Environmental Risk Branch V

# /1/frv~ Environmental Fate and Effects Division (7507P)



### TO: Khue Nguyen Neil Anderson RM 

### 51 Pesticide Re-Evaluation Division (7508P)

Page 

### 1 of46

### Page 2 of 46 

## 1. Executive summary

The Environmental Fate and Effects Division (EFED) , of OPP has completed the problem formulation for the ecological risk, environmental fate, endangered species, and drinking water

assessments for the registration re vi ew of MCPB acid (PC code 019201) and associated sodiu m salts (PC code 019202)

. The herbicide MCPB is currently manufactured as a sodium salt.

The problem formulation describes the methods planned to be used during the completion of the environmental f ate and ecological risk assessment and the drinking water assessment in support of registration review for MCPB acid . As such

, it provides an ove rview of the environmental fate and ecological effects data available for MCPB as well as uncertainties unique to a risk assessment of MCPB . This document also identifies additional studies that would be beneficial to the conduct of an ecological risk assessment. Major findings include:

• The fate database is incomplete based on the environmental fate data requir ements outlined in the 40CFR158. The required studies are listed below.

o Soil Photolysis (835.2410)

o Anaerobic Aquatic metabolism (835.4400)

o ILVs for the submitted Soil and Water ECMs (850

. 6100)

o Storage Stability (835.6100)

• The effects database is incomp lete based on the ecological effects data requirements outlined in the 40CFR158. The required studies are listed below.

o Freshwater invertebrate life cycle (850.1300 )

o Estuarine/Marine invertebrate life cycle (850

. 1350)

o Estuarine/Marine fish ELS (850.1400)

o Adult and Larval acute oral honeybee s tudy ( OECD 213/237 )

o Aquatic Plant Toxicity Test (850.4400)

o Algal Toxicity Study (850.4500)

o Avian Reproduction with Mallard (850.2300)

o Acute Avian Toxicity with Passerine species (850.2100)

• EFED has received the following studies which are currently under review. Once the data evaluations are completed, a determination will be made whether they fulfill the associated data requirements . However, until these determinations have been made, the se data are considered necessary for risk assessment.

o Terrestrial Field Dissipation (835.6100)

o ECMs for Soil and Water Ana l ysis (850.6100)

o Acute toxicity with Sheepshead Minnow ( 850.1075 )

o Freshwater fish ELS (850.1400 )



## 2. Introduction

The herbicide MCPB is p art of the phenoxy class of herbicides and acts as a systemic growth regulating hormone that disrupts hormone (auxin) balance and protein synthesis resulting in plant

### Page 3 of 46 growth abnormalities. The compound is registered for use on peas (field, canned, and dried) and mint. MCPB is applied on c e annually via aerial or ground spray. The purpose of this problem formulation is to broadly review the registered uses of MCPB and identify potentially complete environmental exposure pathway s to be assessed during comprehensive ecological risk

assessment. This document specifically addresses MCPB and its degradates MCPA, 4

- (4

- hydroxy

- o

- tolyoxy) butyric acid, 2,4

- dihydroxyphenyl formate, o

- cresol, and 4

- cholor o

- cresol.

EFED evaluated the mos t recent ecological risk assessments for MCPB in association with the currently available toxicity, exposure, and usage information to determine if sufficient data are available and if further data are needed to support registration review. Recent risk as sessment s include a 2005 assessment in support of the reregistration eligibility decision (RED) for use on

peas and a 200 8 assessment for the use of MCP B on mint

. In addition, EFED considered the latest Agency science policies and risk assessment methodolo gies. The structure of MCPB as well as the chemical names and other identifiers can be found in the chemical identity table

.



## 3. Use Characterization

MCPB sodium salt is currently registered for use on field peas and mint. It is formulated as soluble concentrate , and applied as a postemergent herbicide to control or suppress Canada thistle bud formation. MCPB sodium salt is applied when the peas are tolerant to the herbicide, from shoot emergence until about three leaf nodes before flowering (typicall y 6 to 12 nodes). Canada thistle reduces pea yields through competition and presents problems during harvesting. The thistle plant material is difficult to remove from the harvested crop resulting in loss of crop quality and profit to the grower. Other target weeds include wild mustard, common lambsquarters, pigweed, cocklebur, smartweed, etc. There are two registered products: Thistrol® Herbicide (71368

- 5) and Sodium MCPB Solution (15440

- 38). The registrant is Nufarm, Inc. Both product labels list th e active ingredient (23.5%) as sodium salt of 4

- (2

- methyl

- 4

- chlorophenoxy) butyric acid and 76.5% inert ingredients (not provided). Table 1 summarizes the application rates from the various product labels for all applications.

Table 1. Use of MCPB and MCPB sodium salt.

Crop Products Single Appl. Rate (lb ae/A) Max # Appl./Year Minimum Appl. Interval

(days) Max Appl. Rate/Year

(lb ae/A) Appl. Methods

Peas and

mint Thistrol® Herbicide Peas (0.5

- 1.5) 1 N/A 1.5 Spray/ground and aerial

Mint (0.25

- 0.50) 2 6 months (spring and fall applications) 1.0 Spray/ground and aerial

Peas Sodium MCPB Solution Peas (0.5

- 1.5) 1 N/A 1.5 Spray/ground and aerial

### Page 4 of 46 

## 4. Conclusions from Previous Risk Assessments

**a. Ecological Risk Assessment** 

The most recent comprehensive assessment conducted for MCPB is the Environmental Fate and Ecological Risk Assessment for the Reregistration of MCPB and MCPB Sodium for use on p eas, conducted in 2005 conducted in support of the RED. At the time of the RED , the Agency concluded that MCPB estimated risks exceeded the level of concern (LOC) for the following : 1) chron ic risk to mammals that consume grass, broadleaf plants, and small insects, 2) acute risk to small birds that consume short grasses, 3) non

- targ et terrestrial plants, 4) federally endangered or threatened birds, mammals, aquatic and semi

- aquatic plants.

The major ecological conclu sions presented can be found in Table 2.

Table 2 . Summary of Risk Concerns Identified for MCPB in Previous Assessments

Birds Mammals Terr. Plants Terr. Inverts Fish BCF Aquatic Inverts Aquatic Plants Groundwater Contamination Persistence Degrades of Concern

Yes 1 Yes 2 Yes No No No No No Yes Yes Yes 3

1 Acute risk to avian species. No chronic data was submitted

2 No acute risk; Chronic risk in all weight classes

3 Drinking water assessment completed in 2005 included MCPB and its degradates (MCPA, CHPA/CHPA hexose conjugate



### One of the major degradates, MCPA, is a registered phenoxy herbicide. Refer t o the 2014 MCPA Problem Formulation for additional information on ecological risk conclusions.



## b. **Drinking Water Exposure Assessments**

Two drinking water exposure assessments were previously conducted, one on pea and one on mint in 2005 and 2008, respectively. In the 2005 drinking water assessment from labeled uses on peas, the exposure estimates of MCPB residues produced maximum exposures, on an acid

equivalents basis, of 54.7 μg ae/L (1

- in

- 10

- year peak to represent acute risk), 13.5 μg ae/L (1

- in

10

- year annual mean to represent chronic risk), and 7.3 μg ae/L (30

- year mean to represent cancer risk) for surface water and 2.1 μg ae/L for groundwater.

In the 2008 drinking water assessment from labeled uses on mint, the estimates of MCPB residues produced maximum exposures, on an acid

- equivalents basis, of 9.6 μg ae/L (1

- in

- 10

- year peak to represent acute risk), 9.1 μg ae/L (1

- in

- 10

- year annual mean to represent chronic risk), and 7.8 μg ae/L (30

- year mean to represent cancer risk) for surface wate r. Since the EECs calculated for the mint scenario are lower than the previous estimates in 2005 , EFED concluded that, for the drinking water assessment purpose, the previous estimated drinking water concentrations for use on peas should be used as the re presentative drinking water concentrations for use on mint.

### Page 5 of 46 At that time, estimated drinking water concentrations (EDWC) of MCPB for drinking water from surface and groundwater for human health risk assessment were well below the level of concern [6 % of the acute population adjusted dose (aPAD), and < 22% of the c hronic one (cPAD)] for the most highly exposed population subgroups for either acute or chronic exposures for the general U.S. population or any subgroups. Therefore, the estimated levels in surface water and or ground water did not contribute to posing a dietary concern for MCPB

When EFED receives the anaerobic aquatic metabolism study as requested in this Problem Formulation , a R esidue of Concern Knowledgebase Subcommittee (ROCKS) meeting and an updated drinking water assessment may be needed as part of the Registration Review process. EFED will include the recently revised percentage crop area (PCA) factors as well as the newly

developed PRZM

- GW model to determine EDWCs in groundwater, in the event that HED does need to update dietary exposure estimates from food, new EDWCs for surface and groundwater will be determined.



## c. **Clean Water Act Programs**

The herbicide MCPB is not specifically identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act . No Total Maximum Daily Load (TMDL) criteria have been developed for MCPB. Aquatic benchmarks have not been established for MCPB at http://www.epa.gov/oppefed1/ecorisk_der s/aquatic_life_benchmark.htm . Any data submitted or otherwise located as part of the registration review process may be used to update aquatic life benchmarks if applicable.



## 5. Environmental Fate and Transport

MCPB is an acidic compound (pKa value of 4.6). This acid strength is comparable to that for acetic acid (a component present at a concentration of 5% in vinegar ) . Because of its acidity, MCPB will exist predominately in the ionic (anionic) or salt form at typical environmental pHs. The calculat ed degree of ionization corresponding to MCPB’s acid strength is greater than 99% at pH 7, and ranges from approximately 70% to 99.99+% from pH 5 to 9, respectively. In all formulations registered for field application, MCPB is formulated as its sodium sa lt, which has a water solubility of approximately 200,000 mg/L. For quantification purpose, the application rate information is converted to acid equivalent (ae).

The relatively low vapor pressure (4.0 x10 - 7 

### torr) for MCPB and collateral evidence showing its absence in traps for volatile organic compounds in various laboratory studies indicate that it can be classified as between “non

- volatile” and “intermediate to high volatility” under field conditions.

Tw o aerobic soil metabolism studies have been reviewed. In the first study (MRID 43247601), two by

- products of MCPB , although minor (<10%) in concentration, are also of potential concern because of their structural similarity to parent MCPB . These are: (1 ) MCPA [(4

- chloro

-

### Page 6 of 46 2

- methylphenoxy)acetic acid], which is another registered herbicide of the phenoxy class, and (2) the closely related CHPA

- hexose conjugate [ (4

- chloro

- 2

- methylphenoxy)

- 2

- β

glucopyranoside acetic acid]. In the available aerobic soil metabolism study , these two compounds were each detected at average maxima of approximately 6

- 7% of applied radioactivity during the first 3 to 15 days of incubation, with both decreasing to less than 2% by the end of a 120

- day study. The only major ident ified transformation product was carbon dioxide.

The biotransformation of [phenyl

- U

14 

### C]

- labeled 4

- (4

- chloro

- 2

- methylphenoxy)butyric acid (MCPB) under aerobic conditions was studied in three US soils from North Dakota (MRID 47784801) . MCPB dissipated wit h half

- lives of 8.5 days in the sandy loam soil, 2.5 days in the silty clay loam soil and 4.3 days in the loam soil. Three transformation products were identified. MCPA (4

- chloro

- 2

- methylphenoxyacetic acid) was a major transformation product in all three soils. HMCPA (4

- chloro

- 2

- hydroxymethylphenoxyacetic acid) and PCOC (4

- chloro

- 2

- methylphenol) were minor products.

The MCPA metabolite, as previously documented in its USEPA Reregistration Eligibility Document (dated September 30, 2004) and evidenced in fate studies of MCPB, is similar to MCPB in many characteristics. Although information was lacking for the CHPA

- hexose conjugate, it was assumed to share the same general chemical profile based on structural similarity

. B ecause of their relatively minor presence and lack of persistence inclusion of these two metabolites had little influence on the overall risk assessment summarized in the RED

. Nevertheless, both metabolites were included in combination with parent MCPB as total toxic residues (TTR) with a combined or overall half

- life of 26 days and assumed toxicities and environmental fate properties equivalent to parent. For modeling purposes, in order to allow for natural variation in the microbiological activity of soils, the single soil half life v alue was multiplied by three to approximate an upper confidence bound for an average half

- life from multiple soils. This yielded an aerobic soil metabolism half life of approximately 78 days.

In the soil anaerobic metabolism study, MCPB had a half

- life of approximately 11 days in the total water and soil system (MRID 43015501) . Similarly, for modeling purposes, in order to allow for natural variation in microbiological activity of soils, EFED multiplied the single soil half life by three to approximate an upper confidence bound for an average half

- life from multiple soils. This yielded an anaerobic soil metabolism half life of approximately 34 days. The major transformation product in the aerobic phase of this anaerobic soil metabolism study was MCPA [( 4

- chloro

- 2

- methylphenoxy) acetic acid].

MCPB is essentially stable to hydrolysis (extrapolated half

- life greater than 500 days based on a study lasting only 30 days . MRID 42574301), but photolyze s in water under optimal light exposure conditions with h alf

- lives of approximately 2 to 3 days (MRID 425743052) . When these photolysis half

- lives are used in current EFED aquatic models, factors such as water clarity and depth increase the effective aquatic photolosys half life to approximately 124 times longe r (250 to 400 days)

. Phototransformation products included 4

- (4

- hydroxy

- o

- tolyloxy)butyric acid; 2,4

- dihyroxyphenyl formate; o

- cresol; benzoic acid; and 2

- hydroxyphenyl formate. Specific study information is not available concerning the fate of these pro ducts . These photolysis products are not being considered in the forthcoming the risk assessment in part because they

### Page 7 of 46 are not expected to be persistent in the aquatic environment based on chemical structure and because they are expected to occur at concen trations far below that of the parent compound

.
Adsorption/desorption (batch equilibrium MRID 42693701 ) of MCPB in four soils and one sediment indicate that MCPB is classified as “high ly mobile”. Mean adsorption coefficients (K ads) 

### measured for each of the soils were 1.69, 0.26, 0.65, and 0.78 mL/g (median of 0.72, average of 0.85 mL/g); respective textures of these soils were sandy clay loam, sand, sandy loam, and clay loam. The sediment was a sandy loam (pH of 5.95 and 2.85% orga nic carbon) for which the mean K ads 

### was 10.58 mL/g. Adsorption coefficients normalized for organic carbon (K oc 

### ) are 129.57, 47.91, 85.54, 31.27, and 371.17 mL/g organic carbon for the sandy clay loam, sand, sandy loam, and clay loam soils and sandy loam s ediment, respectively (average K oc 

### for the five values of 130 mL/g organic carbon, median of 86 mL/g organic carbon). The study was not consistent with guidelines because the soils used in the study were not the same as those used in the aerobic soil metab olism studies.

Based on its acid nature and consistent correlations among relatively high solubility, relatively low log octanol

- water partitioning ratio (1.33 at pH 7), and relatively low sorption to soil, MCPB would be prone to leach to ground water and runoff to surface water. Judging from these factors and its lack of persistence in soil, bioconcentration of MCPB is not expected.

A study entitled, “Determination of the degradation of [ 14 

### C]

- MCPB in aerobic water/sediment systems” (MRID 46837205) was r eviewed. This study is classified as supplemental. The material balance was highly variable during the study, ranging from 27. 4

- 100.5% of the applied in the TNO system and from 55.7

- 101.1% in the Kromme Rijn system (reviewer

- calculated values). Variabil ity between replicate samples was high at some intervals. Also, the samples were analyzed for MCPB and its transformation product at only three intervals, which was insufficient to accurately define the rate and pattern of dissipation.

### Page 8 of 46 Table 3

. Physical Chemical Properties and Environmental Fate Parameters of MCPB.

Parameter Value Description Source (MRID)

Selected Physical/Chemical Parameters

Chemical Structure MCPB

Sodium MCPB Test substance

– MCPB

Test substance

– sodium MCPB 2006 EFED Science Chapter

IUAPC Names 4

- (4

- Chloro

- o

- tolyloxy)butyric acid

Sodium 4

- (4

- chloro

- o

- tolyloxy)butyric acid Test substance

– MCPB Test substance

– sodium MCPB 2006 EFED Science Chapter

CAS Names 4

- (4

- Chloro

- 2

- methylphenoxy)butanoic acid

Sodium 4

- (4

- chloro

- 2

- methylphenoxy)butyric acid Test substance

– MCPB

Test substance

– sodium MCPB 2006 EFED Science Chapter

CAS No. 94

- 81

- 5

6062

- 26

- 6 Test substance

– MCPB

Test substance

– sodium MCPB 2006 EFED Science Chapter

Molecular Weight (molecular formula) 228.6 g/mol (C 11 H 13 ClO 3 )

250.7 g/mol (C 11 H 12 ClNaO 3 ) Test substance

– MCPB Test substance

– sodium MCPB 2006 EFED Science Chapter C H 3

Cl O O H O

O H H H

O – O

Cl Na +

### Page 9 of 46 Parameter Value Description Source (MRID)

Smiles Code Cc1cc(Cl)ccc1OCCCC(=O)O

C1C(Cl)=CC=C(OCCCC(=O)OH)C=1C(H )(H)H Test substance

– MCPB

Test substance

– sodium MCPB Online SMILES Translator and Structure File Generator at http://cactus.nci.nih.gov/s ervices/translate/ )

EPISUITE 4.0
Water Solubility (at
20 ° C) 60.4 mg/L (purified technical substance in purified water) 29.9 mg/L at pH 4 3.83 mg/L at pH 7 > 250 g/L at pH 10

200,000 mg/L @ 25 ° C Test substance

– MCPB

Test substance

– MCPB sodium salt 2006 EFED Science Chapter

2006 EFED Science Chapter
Vapor pressure (25°C) 4 x 10 - 7 mm Hg Test substance

- MCPB 2006 EFED Science Chapter

Dissociation constants (pKa ) in

water 4.6 at 20 ° C (in the natural environmental conditions, >50% is present as ionic form) Test substance

- MCPB 2006 EFED Science Chapter

Henry’s Law Constant 3.42 x 10 - 9 atm

- m 3 /mol; estimated at 25 ° C Test substance

- MCPB 2006 EFED Science Chapter
Log octanol

- water partition coefficient (log K OW ) 1.33 (at pH 7 and 20 ° C) 3.45 (at pH 4 and 20 ° C)

- 0.21 (at pH 10 and 20 ° C) Test substance

- MCPB 2006 EFED Science Chapter

Persistence
Hydrolysis half

- life Stable Test substance

- MCPB 42574301

Aqueous photolysis half

- life 2.6 days (pH 7)

Major d egradates: 4

- (4

- hydroxy

- o

- tolyloxy)butyric acid, 2,4

- dihyroxyphenyl formate, o

- cresol Test substance

- MCPB 42574302

Soil photolysis half

life Unacceptable study Test substance

- MCPB 43829901

### Page 10 of 46 Parameter Value Description Source (MRID)

Aerobic soil metabolism half

- life (days) Sandy loam

– 27 days Major degradates:

none

5.1 days in loam soil 3.6 days in silty clay loam soil 10.6 days in sandy loam soil

Major degradate: MCPA Test substance

- MCPB 43247601

47784801

Anaerobic soil metabolism half

- life 7.8 days in soil 18.9 days in water 74.4 days in total system

Major degradate in soil and water:

MCPA Test substance

- MCPB 43015501

Aerobic aquatic metabolism half

- life (total system) TNO water

- sediment system: 6.4 days in water Insufficient data to estimate half

- life in sediment

Kromme Rijn water

- sediment system: Insufficient data to estimate half

- life in

water Insufficient data to estimate half

- life in sediment

Major degradate in total system:

MCPA Test substance

- MCPB 46837205

Mobility
Adsorption/desorptio n (mL/g) Adsorption Freundlich adsorption K
oc values: Sandy loam 130 Sandy 48 Sandy loam 86 Clay loam 31 Clay loam 371 Test substance

- MCPB

42693701

Leaching Column Study Test substance

- MCPB 43466401

### Page 11 of 46 Parameter Value Description Source (MRID)

Field Dissipation

Terrestrial field dissipation half

- life 0

- 15 cm soil pH = 6.2 0

- 15 cm soil texture

- sandy loam Nonlinear MCPB half

- life 6.8 days Nonlinear degradate (MCPA) half

- life 7.8 days Parent and degradate MCPA detected in 0

- 15 cm only (preliminary finding) Test substance

– sodium MCPB 48242801 (in review)



## a. **Transformation Products**

The major organic degradates of MCPB in submitted environmental fate studies were MCPA, 4

- (4

- hydroxy

- o

- tolyloxy)butyric acid, 2,4

- dihyroxyphenyl formate, and o

- cresol and benzoic acid. MCPA was identified as the major degradate in all soil and aquatic metabolism st udies whereas 4

- (4

- hydroxy

- o

- tolyloxy)butyric acid, 2,4

- dihyroxyphenyl formate, and o

- cresol were identified as major degradates in the aqueous pH 7 photolysis study only. Table 4 summarizes the transformation products of MCPB and their maximum amounts for med.

In the terrestrial field dissipation study, the degradate, MCPA, was present at the maximum concentration of 0.1 ppm in the 0

- 15 cm soil zone within two weeks of the application (with a LOQ of 0.01 ppm), and was not detected in any other soil zones ( i.e., 15

- 30 cm, 30

- 45 cm, and 45

- 60 cm) from Day 0 to Days 282 (the end of the study).

A photodegradation pathway in water was proposed in the report (MRID 42574302). MCPB was dechlorinated and h ydrolxylated, resulting in the formation of 4

- (4

- hydroxy

- o

tolyloxy)butyric acid pretty rapidly (reached 27.5% of the applied at Days 7 in the pH 7 solution). Thereafter, 4

- (4

- hydroxy

- o

- tolyloxy)butyric acid degrades to form 2,4

- dihydroxyphenol formate and o

- cresol.

A metabolism pathway was presented in an aer obic soil metabolism study (MRID 43247601). MCPB degrades to (4

- chloro

- 2

- methylphenoxy)acetic acid, which degrades to (4

- chloro

- 2

- methylphenoxy

- 2

- belta

- glucopyranoside acetic acid and conjugates with hexose; there is significant production of CO2 and soil bound residues. Although the pathway was not proposed in the aerobic aquatic metabolism study (MRID 46837205), based on the study results, MCPB degrades to MCPA and is mineralized to bound residues and CO2.

Only one degradate (i.e., 4

- chloro

- o

- cresol) has been identified as the major degradate in all MCPA fate studies. This degradate is also known as 4

- chloro

- 2

- methylphenol which was detected as a minor degradate (ranging from 0.8

- 3.9 % of the applied) in 3 aerobic metabolism soils conducted using MCPB, with study duration of 14

- 21 days (MRID 47787801).Page 12 of 46 Table 3. Major Environmental Degradates i n MCPB (Acid and Sodium Salt) Studies

Code Name/ Synonym Chemical Name Chemical Structur e Study Type Ref. (MRID) Maximum %AR (day) Final %AR (study length

MCPA 4

- chloro

- o

- tolyloxyacetic acid 835.2120 42574301 Not detected

- 835.2240 42574302 Not detected

- 835.2410 43829901 Unacceptable

-

835.4100 43247601 Not major degradate

-

47787801 28.2% (Days 11) in loam soil 29.0% (Days 9) in silty clay loam soil 35.1% (Days 18) in sandy loam soil 10.5% (21 days) 21.9% (14 days) 32.1% (21 days)

835.4200 43015501 34.6% (Days 4)) in total system 34.6% (62 days)

835.4300 46837205 15.5% (Days 7) in total system (TNO water

sediment system)

14.6% (Days 7) in total system (Kromme Rijn water

sediment system) Not analyzed (98 days)

835.6100 48242801 Found in 0

- 15 cm only (0.1 ppm) (Days 14) Not detected (282 days)

4

- (4

- hydroxy

- o

tolyloxy)butyric acid 4

- (4

- hydroxy

- o

tolyloxy)butyric acid 835.2240 42574302 27.5% (Days 7) 5.1% (30 days)

2,4

- dihyroxyphenyl formate 2,4

- dihyroxyphenyl formate 835.2240 42574302 35.3% (Days 14) 33.0% (30 days) C H 3

Cl O O H OPage 13 of 46 Code Name/ Synonym Chemical Name Chemical Structur e Study Type Ref. (MRID) Maximum %AR (day) Final %AR (study length

o

- cresol 2

- methylphenol 835.2240 42574302 47.3% (Days 30) 47.3% (30 days)

### 14 

## 6. Receptors

Table 5 and Table 6 provide a summary of the aquatic and terrestrial taxonomic groups

, respectively, and the most sensitive surrogate species tested to characterize the potential acute and chronic ecological effects of MCPB. Available acute toxicity data indicate that MCPB is slightly to moderately toxic to freshwater fish and slightly toxic to freshwater invertebrates. There was no chronic data or estuarine/marine data submitted for fish or invertebrates. MCPB is classified as moderately toxic to birds on an acute oral ba sis and practically non

- toxic on an acute dietary basis. The compound was classified as slightly toxic to practically non

- toxic to small mammals on an acute oral basis, however, adverse effects were demonstrated in the mammalian subchronic and development al toxicity studies. There is potential for MCPB exposure to non

- target insects due to the foliar application . A vailable data from a honeybee acute toxicity study indicated that technical MCPB is practically non

- toxic to the honeybee. Plant toxicity is expected due the herbicidal prope rties of MCPB.

E FED has recently received the following studies for MCPB. Upon review

, the Agency will determine whether these submissions either satisfy the requirement and/or whether they can be used to inform the ecological risk assessment of MCPB.

o Acute toxicity with Sheepshead Minnow ( 850.1075 )

o Freshwater fish ELS ( 850.1400 )



## a. **Effects to Aquatic Organisms** 

The following t ables present measures of effect in terms acid equivalents. Conversion from active ingredient to acid equivalents was made in accordance with molecular weight difference. One gram

- mole of MCPB acid has a mass of 228.6 7 grams and one gram

- mole of MCPB sodium sal t h as a mass of 250.66 grams; therefore, one unit of the salt would be equivalent to 0.912 units of acid. Hence, the LC 50 

### values from th e toxicity tests with MCPB sodium were converted to acid equivalents by mul tiplying the values by 0.91.

Table 5 . Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for MCPB

Taxonomic Group Study Type Surrogate Species Toxicity Value (all units in

terms of measured acid equivalent) Acute Toxicity Classification Source

Freshwater fish 1 Acute Rainbow Trout ( Oncorhynchus mykiss ) 96

- h LC 50 = 3.9 mg ae /L Moderately toxic 42532608

Chronic 2

-- -- -- --

### 15 Taxonomic Group Study Type Surrogate Species Toxicity Value (all units in

terms of measured acid equivalent) Acute Toxicity Classification Source

Freshwater invertebrates Acute Water Flea ( Daphnia magna ) 48

- h EC 50 = 50.0 mg ae/L Slightly toxic 42532602

Chronic

-- -- -- --

Estuarine/ marine fish Acute 2

-- -- -- --

Chronic

-- -- -- --

Estuarine/ marine invertebrates Acute 2 Eastern Oyster (Crassotrea virginica) 96

- h EC 50 = 63 mg ae/L Slightly toxic 47613401

Chronic

-- -- -- --

Aquatic plants and algae Vascular Duckweed ( Lemna gibba ) NOAEC = <0.01 mg ae/L* EC 50 = 0.21 mg ae/L -- 42532604

Non

vascular Green Algae ( Pseudokirchneriella subcapitata ) NOAEC = <0.31 me ae/L* EC 50 = 0.38 mg ae/L -- 42532605

1 Freshwater fish may be surrogates for aquatic

- phase amphibians.

2 Studies have been submitted and are currently in review *NOEC cannot be determined due to non

- discreet toxicity value therefore definitive endangered species RQs cannot be calculated. EC 05 was not available.



### MCPA is not considered an appropriate substitute to fill MCPB data gaps for aquatic toxicity

. Waiver requests submitted in 2007 requesting MCPA technical acid be used in place of MCPB for aquatic studies were denied on the basis of higher toxicity of MCP B to freshwater fish on an acute basis in comparison to MCPA (D340501) . The acute oral toxicities for MCPB sodium and MCPA sodium conducted using the Rainbow trout are 3.9 mg ae/L (MRID 42532608 ) 

### and >68 mg ae/L MRID (41800902) respectively.



## b. **Effects to Terrestrial Organisms** 

The following tables present measure of effect both in terms of active ingredient and acid equivalents. Conversion from active ingredient to acid equivalents was made in accordance with molecular weight differences as described previously for the aquatic toxicity data

.

### 16 Table 6 . Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for MCPB

Taxonomic Group Study Type Surrogate Species Toxicity Value (all units in terms of measured a cid equivalent ) Acute Toxicity Classification Source

Birds 1 Acute Bobwhite quail ( Colinus virginianus ) LD 50 = 257 mg

ae /kg

- bw Moderately 4 2560801

Sub

- acute dietary Bobwhite quail ( Colinus virginianus ) LC 50 = >4,550

ppm ae Practically

non

- toxic 42560802

Chronic

-- -- -- --

Mammals Acute Oral Laboratory rat ( Rattus norvegicus ) LD 50 = 912 mg/kg

- bw males Practically

non

- toxic 116340

Acute Inhalation Laboratory rat LC 50 = >1.14 mg/L Toxicity Category III 4 1630001

Chronic Rabbit NOAEL = 5 mg/kg/day LOAEL = 20 mg/kg/day Endpoint: Maternal toxicity; developmental effects -- 40865401

Insects Acute

contact Honey bee ( Apis mellifera
L. ) LD 50 = >25 μg/bee Practically

non

- toxic 42532607

Terrestrial plants Seedling Emergence Dicot

– cabbage ( Lactuca sativa ) EC 05 2 = 0.01 lb ae/ A EC 25 = 0.016 lb

ae /A Endpoint: shoot length -- 42560804

Monoc ot

– onion ( Avena sativa ) NOAEC = 0.01 lb

ae /A EC 25 = 0.0 2 lb

ae /A Endpoint: shoot length -- 42560804

1 Birds represent surrogates for terrestrial

- phase amphibians and reptiles. 2IC05 is used when NOAEC is unavailable



### No chronic avian data on MCPB are available. A chronic avian reproduction study with the degradate MCPA was available for the Bobwhite quail and has been used to estimate the chronic

### 17 avian risks of MCPB in previous assessments

. For bird toxicity studies, MCPA is considered an appropriate surrogate because MCPB is expected to rapidly dissociate to MCPA in a bird’s gut due to the chemical properties of MCPB (DP340501)

. Furthermore, a compari son of the MCPB and MCPA avian acute toxicity studies with bobwhite quail indicates that the two compounds have an approximately equivalent acute toxic potential to birds.



## c. **Ecological Incidents**

The ecological incident information system (EIIS) is an OPP database that houses ecological incidents that have been reported to the Agency. When available, EIIS includes date and location of an incident, type and magnitude of effects observed in various species, use(s) of pesticides known or suspected of contributing to the incident, and results of any chemical residue analysis or other analyses conducted during incident investigation. EIIS incidents are categorized according to the certainty that the in cident resulted from pesticide exposure. The Avian Monitoring System (AIMS) is a database administered by the American Bird Conservancy that contains publicly available data on reported avian incidents involving pesticides. Many of the incidents listed i n this database are also in the EIIS.

EIIS returned one terrestrial plant incident in Washington State attributed to MCPB use with a

“ possible ” certainty classification . Incident I021457

- 021 occurred in July 2006 when a misuse of herbicides MCPA, Dicam ba and carfentrazon were aerially applied to a crop of timothy hay and drifted off

- site and resulted in damage to trees. Several plants were damaged in the vicinity of the agricultural area as a result of drift. No other incidents were reported in EIIS, IDS or AIMS.



## 7. Exposure Pathways of Concern

The environmental fate properties and use patterns of MCPB indicate that runoff, leaching, and spray drift represent potential exposure pathways to aquatic organisms; g round deposition, runoff/leaching and spray drift resulting in residues on non

- target plants represent potential exposure pathways to terrestrial organisms.

Avian and mammalian d rinking water and inhalation exposure pathways were screened using the SIP (Scree ning Imbibition Program) and STIR (Screening Tool for Inhalation Risk) screening methods , respectively

. SIP is used to provide an upper bound estimate of exposure of birds and mammals to pesticides through drinking water alone. It is used to determine w hether or not drinking water exposure alone is a potential exposure pathway of concern; it does not aggregate drinking water exposure with other exposure routes. The results of SIP conclude that drinking water exposure alone is not a potential concern for mammals on an acute basis, but exposure through drinking water alone is a potential exposure pathway of concern for mammals on a chronic basis. For avian specie s, that the SIP results indicate exposure through drinking water alone is a potential pathway of concern on an acute basis but exposure through drinking water alone is not a potential pathway of concern on a chronic basis. STIR indicated th at exposure via

### 18 the inhalation pathway was not likely significant for mammals or avian species. SIP and STIR are described in detail at: http://www.epa.gov/oppefed1/models/terrestrial/index.htm

. The results of SIP and STIR are available in Appendix C and D

.



## 8. Analysis Plan

**a. St**  **ressors of Concern**

i. Ecological Risk Assessment

The stressors of ecological concern are MCPB, and degradates MCPA

, 4

- chloro

- o

- cresol

, 4

- (4

- hydroxy

- o

- tolyoxy) butyric acid, 2,4

- dihydoxyphenyl formate, and o

- cresol

. . MCPA and 4

- chloro

- o

- cresol were both fou nd in aerobic soil metabolism studies at 31% and 1

- 4% respectively. 4

- chloro

- o

- cresol is considered a minor degradate with respect to MCPB and a major degradate for MCPA; however, it is included as a stressor of concern to MCPB because of its potential hi gher toxicity than MCPB , as indicated by toxicity estimations generated by QSAR

. 4

- (4

- hydroxy

- o

- tolyoxy) butyric acid, 2,4

- dihydoxyphenyl formate, and o

- cresol are considered as part of the aquatic assessment because they were found as degradates in an aqueous photolysis study (835.2240, MRID 42574302).

MCPA (030501) is registered as an active ingredient and thus has a wel l established toxicity profile. However there is no toxicity data available in ECOTOX for the other degradates. Therefore, quantit ative structure activity relationships (QSARs) were used to estimate the acute toxicity of these degradates to aquatic organisms based on the U SEPA ECOSAR program (version 1.0 ) with EPISUITE (version 4.0)

. ECOSAR is used to compare the toxicity of the paren t chemical relative to the degradates and determine if the degradates have the potential to make a significant contribution to the overall risk to aquatic organisms and should therefore be included as a stressor of concern. All of the QSAR endpoints can b e found in Append ix E

. In comparing the known toxicity of MCPB to the calculated toxicity of MCPB, it was concluded that the 48

- hr Daphnid predicted toxicities were most representative of the actual toxicity values with a known toxicity of 54.8 ppm (MRID 42532602) and a predicted toxicity of 59.2 ppm. Because the known and ECOSAR

- predicted toxicities were one or more orders of magnitude different for other taxa evaluated (fish, algae), only the daphnia QSAR was used to evaluate the potential toxicity of th e degradates. Tab le 7 shows the predicted toxicities for each of the degradates as generated by QSAR. QSAR estimates for aquatic species indicate a higher toxicity for o

- cresol and 4

- chloro

cresol relative to that of MCPB.

Table 7

. 48

- hr LC 50 

### values pr edicted for Daphnia using ECOSAR (ppm)

MCPB MCPA 4

- (4

- hydroxy

o - tolyloxy) butyric acid 2

- 4

- dihyroxyphenyl formate o - cresol 4

- chloro

cresol

59.2 1 328.5 1 168.6 1 157.3 2 5.2 3 3.0 3

1 Endpoint based on Neutral Organics Acid QSAR

2 Endpoint based on Phenols, Poly QSAR

3 Endpoint based on Phenols QSAR

### 19 ii. 

### Formulation Impurities



### Various phenoxy herbicides are known to contain dioxin/furan impurities as a result of manufacturing processes (Holt, et. al. 2010). Data pertaining to dioxin/furan impurities in MCPB formulations (up to 17 known dioxin/furan congeners) will be considered in the upcoming environmental risk assessment. Previously submitted dioxin/furan data for MCPB were below levels of quantitation (LOQ) (MRIDs 45524105 and 47374801). However, the Agenc y is aware that lower limits of quantitation of dioxins/furans by one or more orders of magnitude are now achievable through technological advances in analytical chemistry. Therefore, the Agency requests any additional information on the presence of dioxi ns/furans impurities in MCPA formulated products that may be available based on currently achievable LOQs. Absent additional information, the Agency will use best available information (including appropriate assumptions related to reported LOQs) for deter mining the potential for exposures of concern at the time of risk assessment.

iii. Drinking Water

When EFED receives an acceptable anaerobic aquatic metabolism study as requested in this PF, a ROCKS meeting and an updated drinking water assessment may be nee ded as part of the Registration Review process. EFED will include the recently revised percentage crop area (PCA) factors as well as the newly

- developed PRZM

- GW model to determine EDWCs in groundwater, in the event that HED does need to update dietary exp osure estimates from food, new EDWCs for surface and groundwater will be determined.



## b. **Measures of Exposure**

EFED will use standard available models to evaluate potential exposures to aquatic and terrestrial organisms as described at http://www.epa.gov/pesticide/science/models_db.htm

.
Aquatic exposure estimates will be based on estimated environmental concentrations (EECs) generated using the Pesticide Ro ot Zone Model (PRZM 3.12.2 dated May 12, 3005) coupled with the Exposure Analysis Model System (EXAMS 2.98.04.06 dated April 25, 2005) to simulate a waterbody that is considered representative of vulnerable aquatic environmental ( e.g. , ponds and streams in headwater watersheds). Terrestrial exposure will be estimated using a model (T

- REX version 1.5) that assumes direct application to a variety of avian, mammalian and reptilian food items. Exposure to terrestrial plants will be estimated using a model (Te rrPlant; version 1.2.2) that assumes MCPB drifts or moves with runoff to adjacent habitats

.
Two spray drift models, AgDISP and/or AgDRIFT, will be used to assess exposures of aquatic and terrestrial organisms to MCPB deposited in terrestrial and aquatic habitats by spray drift. AgDRIFT (version 2.1.1; dated 03/07/2012) is the model most commonly used by EFE D to simulate spray drift into terrestrial and aquatic environments. AgDISP (version 8.26; dated 03/07/2012) is used when a parameter needs to be modeled that is not available in AgDRIFT. Spray drift analysis will be an important part of the a nalysis in defining the potential area of effects for listed species.

### 20 Screening level calculations using SIP have suggested th at drinking water exposure may be significant. This exposure pathway may be further considered at the time of the risk assessmen t ( Appendix C and D ).

i. Available Monitoring Data

The Agency is aware of aquatic monitoring conducted by federal and state agencies and this information will be considered in the assessment to the extent that data on MCPB or other residues of concern are available. For example, according to the USGS database, MCPB was not detected in 3,232 surface water and ground water samples collected in the United States.



## c. **Measures of Effect**

Toxicity data presented in Section 3 of this problem formulation will be used to calculate risk quotients. Any additional information submitted by the registrant or found in the open literature prior to conduct of the risk assessment will also be considered. The open literature studies are identified using EPA’s ECOTOXicology database (ECOTOX) (USEPA, 2007 c ), which employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also provide insight into the direct and indirect effects of pesticides on biotic communities from loss of species that are sensitive to the chemicals and from changes in structure and functional characteristics of the affected communities.



## 9. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to federally listed threatened and/or endangered (listed) species from registered uses of pesticides in registration review

. The process for evaluating potential risks to listed species is further described at http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm

.



## 10. Endocrine Disruptor Screening Program

Under Federal Food Drug and Cosmetic Act (FFDCA section 408(p), the Agency must screen all pesticide chemicals for potential endocrine disruptor activity. Between October 2009 and February 2010, EPA issues test orders/data call

- ins for the first g roup of 67 chemicals, which compromises 58 pesticide active ingredients and 9 inert ingredients. The herbicide MCPB is not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP . For further information on th e status of the EDSP, policies and procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 screening batter, please visit our website http://www.epa.gov/endo/

.

### 21 

## 11. Preliminary Identificati on of Data Gaps

**a. Environmental**  **Fate**

Table 8 identifies environmental fate studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not further data are needed to support the risk assessment.

• The soil photolysis study (MRID 43829901) was determined not scientifically valid and it does not provide useful information on the photodegradation of MCPB on sandy loam soil and is therefore classified as unacceptable. A new soil photolysis study (835.2 410) is needed.

• Since the registrant has not submitted any anaerobic aquatic metabolism study, as required for all pesticides with terrestrial use pattern, the registrant must submit an anaerobic aquatic metabolism study (835.4400).

• The registrant must s ubmit ILVs (850.6100) for the ECMs (MRIDs 46837203 and 47163505) that the registrant submitted.

• Storage stability information are needed to support the TFD study (MRID 48242801).

Table 8. Submitted Environmental Fate Data for MCPB

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Are data needed to conduct risk
assessment Justification and Assumptions EPA will Make in Absence of Data

835.2120 Hydrolysis 42574301 Acceptable No Not Applicable

835.2240 Aqueous photolysis 42574302 Acceptable No Not Applicable

835.2410 Soil photolysis 43829901 Unacceptable Yes Assuming stable

835.4100 Aerobic soil metabolism 43247601 Acceptable No Not Applicable 47784801 Supplemental

835.4200 Anaerobic soil metabolism 43015501 Acceptable No Not Applicable

835.4300 Aerobic aquatic metabolism 46837205 Supplemental No Not Applicable

835.4400 Anaerobic aquatic metabolism No study submitted --- Yes A ssuming stable

### 22 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Are data needed to conduct risk
assessment Justification and Assumptions EPA will Make in Absence of Data

835.1230 835.1240 Adsorption/ desorption 42693701 Acceptable No Not Applicable

Leaching 43466401 Supplemental No Not Applicable

835.1410 Volatility

laboratory --- --- --- Not Applicable

835.8100 Volatility Field

--- --- --- Not Applicable

835.6100 Terrestrial field dissipation 48242801 In review No Not Applicable

850.6100 Analytical method in soil ( ECM ) 46837203 In review No Not Applicable

Analytical method in soil (ILV) --- --- Yes ILV is needed to validate ECM

835.6200

Aquatic field dissipation --- --- --- Not Applicable

850.6100 Analytical method in water (ECM) 47163505 In review

--- Not Applicable

Analytical method in water (ILV) --- --- Yes ILV is needed to validate ECM

850.1730 Fish BCF

--- ---- --- Not applicable due to low Log
K ow 835.6100 Storage stability

--- ---- Yes TFD study may be invalid



## b. **Effects**

Table 9 and table 10 identify ecological effects studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not further data are needed

### 23 in order to support risk assessment. Rationale for the additional data requested is presented below the tables.

Table 9 . Aquatic 

### Ecological Effects Data for MCPB

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Are data needed to conduct risk assessment? Justification and Assumptions EPA will Make in Absence of Data

- Some Example texts are include

850.1010 Freshwater invertebrate acute toxicity 42532602 Acceptable No

--

850.1025 850.1035 850.1045 850.1055 Saltwater invertebrate acute toxicity 47613401 Acceptable No

--

850.1075 Freshwater fish acute toxicity 42532608 Acceptable

No

-- 42532601 Acceptable

850.1075 Saltwater fish acute toxicity None NA Yes Study is currently under review; data requirement still considered outstanding.

850.1300 Freshwater invertebrate life cycle None NA Yes A guideline study compliant to the saltwater invertebrate life cycle study is required.

850.1350 Saltwater invertebrates life cycle None NA Yes A guideline study compliant to the saltwater invertebrate life cycle study is require d.

850.1400 Freshwater fish early

- life stage None NA Yes Study is currently under review; data requirement still considered outstanding.

850.1400 Saltwater fish early

- life stage None NA Yes A guideline study compliant to the saltwater fish early

- life stage study is required.

850.1500 Fish life cycle None NA No

850.4400 Aquatic plant Toxicity Test using Lemna

spp. 42532604 Acceptable Yes NOAEC from listed studies cannot be determined due to treatment

related effects at all test concentrations. Therefore, definitive endangered species RQs , which are based on plant NOAECs, cannot be calculated. New studies are being requested for derivation of a definitive NOAEC endpoint.

850.4500 Algal toxi city 42532605

Acceptable Yes NOAEC from listed studies cannot be determined due to treatment

related effects at all test concentions.
T herefore definitive endangered species RQs , which are based on 42532603

### 24 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Are data needed to conduct risk assessment? Justification and Assumptions EPA will Make in Absence of Data

- Some Example texts are include

42532609 plant NOAECs, cannot be calculated. New studies are being requested for derivation of a definitive NOAEC endpoint.

42532606

Table 10 . Terrestrial Ecological Effects Data for MCPB

OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Are data needed for risk assessment? Current Additional Data Need

850.2100 Avian oral toxicity 42560801 Acceptable Yes An acute oral toxicity test conducted using a passerine species is required.

In lieu of a passerine study conducted using MCPB, the Agency will accept acute passerine data on MCPA due to rapid bioatransofrmation of MCPB to MC PA expected in the avian gut and their similarity in avian oral toxicity to birds.

850.2200 Avian dietary toxicity 42560802 Acce ptable No

--
42560803 Acceptable

850.2300 Avian reproduction 43505201 Acceptable Yes An avian reproduction toxicity performed using MCPA on the Bobwhite is available and considered an appropriate substitution for MCPB. There are currently no avian reproduction data available using MCPA or MCPB for the mallard and is thus considered a data gap.

In lieu of a mallard study conducted using MCPB, the Agency will accept mallard data on MCPA due to the rapid biotransformation of MCPB to MCPA expected in the avian gut and their similarity in avian oral toxicity to birds.

. MCPA

Non

guideline Avian inhalation 41630001 Acceptable No

### 25 OCSPP Guideline Data Requirement Submitted Studies (MRID) Study Classifications Are data needed for risk assessment? Current Additional Data Need

850.3020 Honey bee

acute contact toxicity 42532607 Acceptable No

--

OECD 213/237 Acute Oral Adult and Larval Honeybee None NA Yes Studies are requested on basis of assessing risk to larval life stages of bees which are expected to be exposed via nectar and/or pollen through systemic transport of MCPB.

850.3030 Honey bee residue on foliage None NA No The LD50 for the honey bee acute contact study was >25 μg/L and considered practically non toxic the honey bee

850.3040 Field testing for pollinators None NA No The LD50 for the honey bee acute contact study was >25 μg/L and considered practically non toxic the honey bee. At this time field testing for pollinators is not being requested.

850.4100 S eedling
E mergence and Seedling Growth 42560804 Acceptable No

--

850.4150 Vegetative Vigor 42560804 Acceptable No

--

42560804

### 26 

## 12. References

Jones, R.D. et al., 2000. Guidance for use of the Index Reservoir and Percent Crop Area Factor in Drinking Water Assessments (March 21, 2000). Office of Pesticide Programs, Environmental Fate and Effects Division, U.S. Environmental Protection Agency. Arlington, VA.

USEPA. 1999. Guidance for Use of the Index Reservoir in Drinking Water Exposure Assessments. Arlington, VA.

USEPA. 2000. Drinking Water Screening Level Assessment. Part A: Applying a Percent Crop Area Adjustment to Tier II Surface Water Model Estimates for Pesticide Drinking Water Exposure Assessments. FQPA Science Policy Document .Public Comment Draft September 1, 2000. Federal Register: October 11, 2000 (volume 65, number 197). Electronic copy available at http://www. epa.gov/pesticides/trac/science/ .

USEPA. 2002a. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version II (February 28, 2002). Office of Pesticide Programs, Environmental Fate and Effects Divisio n, U.S. Environmental Protection Agency. Arlington, VA.

U.S. EPA. 2002b. Pesticide Root Zone Model (PRZM) Field and Orchard Crop Scenarios: Standard Procedures for Conducting Quality Control and Quality Assurance. Office of Pesticide Programs, Environment al Fate and Effects Division, U.S. Environmental Protection Agency. Arlington, VA.

U.S. EPA. 2003b. Use of Regional Percent Crop Area Factors in Refined Drinking Water Assessments. US EPA Office of Pesticide Programs (OPP), Environmental Fate and Effects Division (EFED), Water Quality Technical Team (WQTT). Arlington, VA

USEPA, 2003c. SCI

- GROW 2.3: Windows Version of SCI

- GROW. September 30, 2003. Office of Pesticide Programs, Environmental Fate and Effects Division, U.S. Environmental Protection Agency. Arlington, VA.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs . United States Environmental Protection Agency (USEPA). Environmental Fate and Effects Division. Office of Pesticide Programs. Available a t http://www.epa.gov/espp/consultation/ecorisk

- overview.pdf

.

Holt. E., Weber, R., Stevenson, G., and Gaur, C. 2010. Polychlorinated Dibenzo

- p

- Dioxins and Dibenzofurans (PCDD/Fs) Impurities in Pesticides: A Neglected Source of Contemporary

Relevance. Environ. Sci. Technol. 44 , 5409

- 5415.

45524105 Grienberger, G. (2000) Tetra

-- To Hepta

- Chlorinated Dioxins and Furanes in Seven

### 27 Batches of Technical 4

- (4

- Chloro

- 2

- methylphenoxy)butanoic Acid (MCPB): Lab Project Number: NUFARM 1199 MCPB: 60288. Unpublished study prepared by Institut fur Industrie

- und Umweltanalytik . 193 p. {OPPTS 830.1700}

47374801 Grienberger, G. (2006) Tetra

- To Hepta

- Chlorinated Dioxins and Furans in Seven Batches of Technical 4

- (4

- Chloro

- 2

- methylphenoxy) Butanoic Acid (MCPB). Project Number: 0306A, GLP/AM/001. Unpublished study prepared by UIS Umweltinstitut Synlab GmbH. 236 p.

### 28 

## Appendi **x A**

OPPIN Bibliography for MCPB and its Salt

Environmental Fate



## 161

**- 1**  **Hydrolysis**

MRID Citation Reference

42574301 Das, Y. (1992) Hydrolysis of (carbon 14)MCPB in Aqueous Solutions Buffered at pH 5, 7 and 9: Lab Project Number: 92010: 92

- 06. Unpublished study prepared by Innovative Scientific Services, Inc. 77 p.



## 161

**- 2**  **Photodegradation**

**- water** 

MRID Citation Reference

42574302 Das, Y. (1992) Photodegradation of (carbon 14)MCPB in Aqueous Solutions Buffered at pH 5, 7 and 9 under Artificial Sunlight: Lab Project Number: 92011: 92

- 07. Unpublished study prepared by Innovative Scientific Services, Inc. 174 p.



## 161

**- 3**  **Photodeg radation** 

**- soil** 

MRID Citation Reference

43829901 Ferreira, E.; John, A.; Lowden, P.; et al. (1995) MCPB Soil Photolysis Study: Amended Report: Lab Project Number: P92/126 Unpublished study prepared by Rhone

- Poulenc Agriculture Ltd. 75 p. (Amended version of 42519101).

### 29 

## 161

**- 4**  **Photodegradation**

**- air** 

MRID Citation Reference

46837204 Baxby, M. (2002) Validation of an Analytical Method for the Determination of 4

- (4

- Chloro

- 2

- Methylphenoxy) Butyric Acid (MCPB) in Air: Final Report. Project Number: 02/0177. Unpublished study

prepa red by A H Marks & Co Ltd. 41 p.



## 162

**- 1**  **Aerobic soil metabolism**

MRID Citation Reference

47787801 J Oddy, A. and R. Brett. (2009). [ 14 

### C]MCPB: Rate of degradation in three soils at 22°C. Unpublished study performed by Battelle UK Ltd., Ongar, Essex, UK; and sponsored and submitted by MCPB Task Force, Raleigh, North Carolina. Battelle UK Study No. and Battelle Report No.: FK/08/001. Study started November 11, 2008, and completed January 15, 2009 (p. 5). Final report i ssued June 11, 2009.

43247601 John, A.; Jones, M.; Lowden, P.; et al. (1994) MCPB: Aerobic Soil Metabolism: Lab Project Number: P/93/194. Unpublished study prepared by Rhone

- Poulenc Agriculture Ltd. 108 p.



## 162

**- 2**  **Anaerobic soil metabolism**

MRID Citation Reference

43015501 Goodyear, A. (1993) Carbon 14

- MCPB: Anaerobic Soil Metabolism: Final Report: Lab Project Number: 68/131

- 1015: 68/131: 200352. Unpublished study prepared by Hazleton UK. 90 p.



## 162

**- 4**  **Aerobic aquatic metab.**

MRID Citation Reference

### 30 46837205 van Dijk, N.; Pigott, G. (2003) Determination of the Degradation of [Carbon 14]

- MCPB in Aerobic Water/Sediment Systems: Final Report. Project Number: 4985, 010/46139. Unpublished study prepared by TNO Voeding. 67 p.



## 163

**- 1**  **Leach/adsorp/desorption**

MRID Citation Reference

42693701 Robson, M. (1993) Determination of Adsorption/Desorption Characteristics of 4

- (2

- Methyl,4

- Chlorophenoxy) Butyric Acid (MCPB) in Soil: Final Report: Lab Project Number: 68/127: 7414. Unpublished study prepared by Hazleton UK. 81 p.

43466401 John, A.; Jone s, M.; Lowden, P. (1994) MCPB: Fresh and Aged Leaching Study in Five Soils: Lab Project Number: P 92/333: 200724: RPAL P92/333. Unpublished study prepared by Rhone

- Poulenc Agriculture Ltd. 142 p.



## 164

**- 1**  **Terrestrial field dissipation**

MRID Citation Reference

48242801 Panara, J. (2010) Terrestrial Dissipation of MCPB Sodium Salt in Wisconsin: Final Report. Project Number: 09/00990. Unpublished study prepared by Eurofins / Grayson Research, Ltd. 541 p.



## Analytical method

MRID Citation Reference

46837203 Mahmood, T. (2003) Validation of a Method for the Analysis of MCPB and MCPA in Soil: Final Report. Project Number: R/03/03. Unpublished study prepared by A H Marks & Co Ltd. 39 p.

### 31 47163505 Harper, H. (2005) MCPA, 2,4

- D, Mecoprop, Dichlorprop, MCPB and 2,4

- DB: Validation of the Methodology for the Determination of Residue in Drinking and Surface Waters: Final Report. Project Number: TFT/005/052350. Unpublished study prepared by Huntingdon Research Center. 220 p.

### 32 

## Appendix B

OPPIN Bibliography for MCPB and its Salt

**71**

**- 1**  **Avian Dietary Toxicity**

MRID Citation Reference

116348

42560801

42532608 Weatherholtz, W. (1969) Dietary Administration

-- Pekin Ducklings: MCPB: Project No. 517

- 109. Final rept. (Unpublished study received on unknown date under 1F1051; prepared by TRW, Inc., sub

- mitted by Rhodia, Inc., New Brunswick, NJ; CDL:091885

- J)

Pederse n, C.; Helsten, B. (1992) MCPB Sodium: 14

- day Acute Oral LD50 Study in Bobwhite Quail: Lab Project Number: 108

- 016

- 03. Unpublished study prepared by Bio

- Life Associates, Ltd. 59 p.

Bettencourt, M.J. 1992. MCPB Sodium

- Acute toxicity to rainbow trout (Onc orhyn

- chus mykiss) under flow

- through conditions. Unpublished study performed by Springborn Laboratories, Inc., Wareham, MA and sponsored by Rhane

Poulenc Agrochemie, Research Triangle Park, NC. SLI Report Number 92

- 7

- 4228.



## 71

**- 2**  **Avian Dietary Toxici ty** 

MRID Citation Reference

116348

42560802

42560803 Weatherholtz, W. (1969) Dietary Administration

-- Pekin Ducklings: MCPB: Project No. 517

- 109. Final rept. (Unpublished study received on unknown date under 1F1051; prepared by TRW, Inc., sub

- mitted by Rhodia, Inc., New Brunswick, NJ; CDL:091885

- J

Pedersen, C.; Helsten, B. (1992) MCPB Sodium: 8

- day Acute Dietary LC50 Study in Bobwhite Quail: Lab Project Number: 108

- 014

- 01. Unpublished study prepared by Bio

- Life Associates, Ltd. 103 p.

Pe dersen, C.; Helsten, B. (1992) MCPB Sodium: 8

- day Acute Dietary LC50 Study in Mallard Ducklings: Lab Project Number: 108

- 015

- 02. Unpublished study prepared by Bio

- Life Associates,

### 33 Ltd. 103 p



## 72

**- 1**  **Freshwater Fish Acute**

MRID Citation Reference

84752 Bentley, R.E.; Macek, K.J. (1976) Some Effects of Exposure to Herbicides on Behavior, Survival and Selected Physiological Parameters of Carp (?~Cyprinus carpio~?): ?Submitter| T

- 2288. (Unpublished study received Oct 8, 1981 under 476

- 2107; prepared by EG & G, Bionomics, submitted by Stauffer Chemical Co., Rich42532608mond, Calif.; CDL:246020

- S)

4253260 8 Bettancourt, M. (1992) MCPB Sodium

-- Acute Toxicity to Rainbow Trout (Oncorrhynchus mykiss) under Flow

through Conditions: Final Repo rt: Lab Project Number: 92

- 7

- 4338: 10566.0392.6227. 108. Unpublished study prepared by Springborn Labs, Inc. 64 p.

4253260 1 Bettencourt, M. (1992) MCPB Sodium

-- Acute Toxicity to Bluegill Sunfish (Lepomis macrochirus) under Flow

through Conditions: Final Report: Lab Project Number: 92

- 8

- 4363: 10566.0392.6226.105. Unpublished study prepared by Springborn Labs, Inc. 64 p.



## 850.1075 **Fish acute toxicity test, freshwater and marine**

MRID Citation Reference

47262101 Pigott, G. (2007) Rationale Document for Requesting a Waiver for Oyster Acute Toxicity Test (Shell Deposition) and Fish Acute Toxicity Test Freshwater and Marine: MCPB Technical Acid in Response to Generic and Product Specific Data Call

- In Notice dated March 6, 2007. Unpublished stud y prepared by MCPB Task Force. 4 p.



## 72

**- 2**  **Freshwater Invertebrate Acute**

MRID Citation Reference

42532602 Christensen, K. (1992) MCPB Sodium: Determination of Effects on Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab Project Number:

### 34 92

- 8

- 4377. Unpublished study prepared by Springborn Labs, Inc. 208 p.



## 850.102 **5 Oyste**  **r acute toxicity test (shell deposition)** 

MRID Citation Reference

47262101 Pigott, G. (2007) Rationale Document for Requesting a Waiver for Oyster Acute Toxicity Test (Shell Deposition) and Fish Acute Toxicity Test Freshwater and Marine: MCPB Technical Acid in Response to Generic and Product Specific Data Call

- In Notice dated March 6, 2007. Unpublished study prepared by MCPB Task Force. 4 p.

47613401 Hicks, S. (2008) MCPB Na 400g/l: Effect on New Shell Growth of the Eastern Oyster (Crassostrea virginica). Project Number: 63950, 94/81/5, S756. Unpublished study prepared by ABC Laboratories, Inc. 58 p.



## 72

**- 4**  **Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study** 

MRID Citation Reference

84752 Bentley, R.E.; Macek, K.J. (1976) Some Effects of Exposure to Herbicides on Behavior, Survival and Selected Physiological Parameters of Carp (?~Cyprinus carpio~?): ?Submitter| T

- 2288. (Unpublished study received Oct 8, 1981 under 476

- 2107; prepared by EG & G, Bionomics, submitted by Stauffer Chemical Co., Rich

- mond, Calif.; CDL:246020

- S)



## 850.1400 **Fish early**

**- life stage toxicity test** 

MRID Citation Reference

47261801 Pigott, G. (2007) Rationale Document for Requesting a Waiver for Fish Early

- Life Stage Toxicity Test (Data Requirement 850.1400) for MCPB Technical Acid and MCPB Sodium Salt in Response to Generic and Product Specific Data Call

- In Notice Dated March 6, 2007. Project Number: 850/1400/WAIVER/MCPB. Unpublished study prepared by A.H. Marks and Co, Ltd. 4 p.

### 35 

## 122

**- 1**  **Vegetative Vigor**

**- tier I** 

MRID Citation Reference

42560804 Christensen, K. (1992) MCPB Sodium: Determination of Effects on Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab Project Number: 92

- 8

- 4377. Unpublished study prepared by Springborn Labs, Inc. 208 p.



## 123

**- 1a Seedling Emergence** 

**- Tier II** 

MRID Citation Reference

4256080 4 Christensen, K. (1992) MCPB Sodium: Determination of Effects on Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab Project Number: 92

- 8

- 4377. Unpublished study prepared by Springborn Labs, Inc. 208 p.



## 123

**- 1b Vegetative Vigor** 

**- Tier II** 

MRID Citation Reference

42560804 Christensen, K. (1992) MCPB Sodium: Determination of Effects on Seed Germination, Seedling Emergence and Vegetative Vigor of Ten Plant Species: Final Report: Lab Project Number: 92

- 8

- 4377. Unpublished study prepared by Springborn Labs, Inc. 208 p

.



## 122

**- 2**  **Aquatic Plant Algae**

**- tier l** 

MRID Citation Reference

42532603 Hoberg, J. (1992) MCPB Sodium

-- Toxicity to the Freshwater Blue

- green Alga, Anabaena flos

- aquae: Final Report: Lab Project Number: 92

- 8

- 4381: 10566.0392.6230.420. Unpublished study prepared by Springborn Labs, Inc. 54 p.

42532604 Hoberg, J. (1992) MCPB Sodium

-- Toxicity to the Duckweed Lemna gibba: Final Report: Lab Project Number: 92

- 8

- 5368: 10566. 0392.6229.410. Unpublished study prepared by

### 36 Springborn Labs, Inc . 61 p.

42532605 Hoberg, J. (1992) MCPB Sodium

-- Toxicity to the Freshwater Green Alga, Selenastrum capricornutum: Final Report: Lab Project Number: 92

- 8

- 4361: 10566.0392.6232.430. Unpublished study prepared by Springborn Labs, Inc. 58 p.

42532606 Hoberg, J. (1992) MCPB Sodium

-- Toxicity to the Marine Diatom, Skeletonema costatum: Final Report: Lab Project Number: 92

- 8

- 4372: 10566.0392.6233.450. Unpublished study prepared by Springborn Labs, Inc. 59 p.

42532609 Hoberg, J. (1992) MCPB Sodium

-- Toxici ty to the Freshwater Diatom, Navicula pelliculosa: Final Report: Lab Project Number: 92

- 10

- 4448: 10566.0392.6231 440. Unpublished study prepared by Springborn Labs, Inc. 60 p.

46743367 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Selenastrum capricornutum). Project Number: AHM/147/023375. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 41 p.

46743802 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Navicula pe lliculosa). Project Number: AHM/148/024534. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 39 p.

46743803 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Higher Plant (Lemna) Growth Inhibition Test. Project Number: AHM/149/023838. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 44 p.

47200201 Albuquerque, R. (2003) Supplemental Information to MRID 46743801: MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Selenastrum capricornutum). Project Number: AHM /147/023375, AHM/147. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 33 p.

47200202 Albuquerque, R. (2003) Supplemental Information to MRID 46743802: MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Navicula pelliculosa). Pr oject Number: AHM/148/024534, AHM/148. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 78 p.

47200203 Albuquerque, R. (2003) Supplemental Information to MRID: 46743803: MCPB 400G/L Aqueous Formulation: Higher Plant (Lemna) Growth Inhibition Test. Project Number: AHM/149/023828, AHM/149. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 91 p.

### 37 

## 123

**- 2**  **Aquatic plant growth**

MRID Citation Reference

46743801 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Selenastrum capricornutum). Project Number: AHM/147/023375. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 41 p.

46743802 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Navicula pelliculosa). Project Number: AHM/148/024534. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 39 p.

46743803 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Higher Plant (Lemna) Growth Inhibition Test. Project Number: AHM/ 149/023838. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 44 p.

47200201 Albuquerque, R. (2003) Supplemental Information to MRID 46743801: MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Selenastrum capricornutum). Project Number: AHM/147/023375, AHM/147. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 33 p.

47200202 Albuquerque, R. (2003) Supplemental Information to MRID 46743802: MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Navicula pell iculosa). Project Number: AHM/148/024534, AHM/148. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 78 p.

47200203 Albuquerque, R. (2003) Supplemental Information to MRID: 46743803: MCPB 400G/L Aqueous Formulation: Higher Plant (Lemna) Growth Inhibition Test. Project Number: AHM/149/023828, AHM/149. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 91 p



## 850.5400 **Algal toxicity, Tiers 1 and II**

MRID Citation Reference

46743801 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Selenastrum capricornutum). Project Number: AHM/147/023375. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 41 p.

### 38 46743802 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Algal Gro wth Inhibition Assay (Navicula pelliculosa). Project Number: AHM/148/024534. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 39 p.

47200201 Albuquerque, R. (2003) Supplemental Information to MRID 46743801: MCPB 400 G/L Aqueous Formulation: A lgal Growth Inhibition Assay (Selenastrum capricornutum). Project Number: AHM/147/023375, AHM/147. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 33 p.

47200202 Albuquerque, R. (2003) Supplemental Information to MRID 46743802: MCPB 400 G/L Aqueous Formulation: Algal Growth Inhibition Assay (Navicula pelliculosa). Project Number: AHM/148/024534, AHM/148. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 78



## 850.4400 **Aquatic plant toxicity test using Lemna spp. Tiers I and II** 

MRID Citation Reference

46743803 Albuquerque, R. (2003) MCPB 400 G/L Aqueous Formulation: Higher Plant (Lemna) Growth Inhibition Test. Project Number: AHM/149/023838. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 44 p.

47200203 Albuquerque, R. (2003) Supplemental Information to MRID: 46743803: MCPB 400G/L Aqueous Formulation: Higher Plant (Lemna) Growth Inhibition Test. Project Number: AHM/149/023828, AHM/149. Unpublished study prepared by Huntingdon Life Sciences, Ltd. 91 p.



## 141

**- 1 Acute Honey Bee Contact** 

MRID Citation Reference

42532607 Maggi, V. (1992) Acute Contact Toxicity of MCPB Sodium Salt to Honey Bees (Apis melliflora L.): Lab Project Number: CAR 169

- 92. Unpublished study prepared by California Agricultural Research, Inc. 22 p.



## Non

**- Guideline Study** 

MRID Citation Reference

### 39 21958 Mason, D.F.J. (19??) Summary of Toxicological Work. (Unpublished study received Apr 12, 1962 under unknown admin. no.; submitted by May Baker, Ltd., Montreal, Canada; CDL:102710

- A)

42669 Rhone

- Poulenc Chemical Company (19??) Summary of Toxicological Wor k. (Unpublished study received Apr 12, 1962 under unknown admin. no.; CDL:102686

- A)

42670 Rhone

- Poulenc Chemical Company (1961) Biochemical Link between 4

- Phenoxy butyric acids and Phenoxy acetic acid. (Unpublished study received Apr 12, 1962 under unkn own admin. no.; CDL: 102686

- B)

53737 Thomson, W.T. (1967) Agricultural Chemicals

-- Book II: Herbicides. Rev. Davis, Calif.: Thomson Publications. (pp. 12

- 14 only; also~In~unpublished submission received Aug 15, 1977 under 38117

- 3; submitted by Akzo Zout Chemie Nederland, B.V., Amster

- dam, Holland; CDL:231355

- G)

53754 Way, J.M. (1969) Toxicity and hazards to man, domestic animals, and wildlife from some commonly used auxin herbicides. Residue Reviews 26:37

- 62. (Also~In~unpublished submission received Aug 15, 1977 under 38117

- 2; submitted by Akzo Zout Chemie Neder

- land, B.V., Amsterdam, Holland; CDL:231352

- O)

55823 Pimentel, D. (1971) Ecological Effects of Pesticides on Non

target Species. By Cornell Univ., Dept. of Entomology and Limnology. Washington, D.C.: Executive Office of the President, Office of Science and Te chnology. (p. 113 only; available from: Super

- intendent of Documents, U.S. Government Printing Office, Wash

- ington, DC, 20402; stock no. 4106

- 0029, published study; CDL: 241577

- U)

73213 Guardigli, A.; Chow, W. (1970) Identification and Semiquantitativ e Determination of 4

- (2

- Methyl, 4

- chlorophenoxy) Butyric Acid (MCPB) and Its Metabolite 2

- Methyl, 4

- Chlorophenoxy Acetic Acid (MCPA) by Thin Layer Chromatography. Method no. 106 dated Mar 3, 1970. (Unpublished study received on unknown date under 1F1051;

s ubmitted by Rhodia, Inc., New Brunswick, N.J.; CDL: 098804

- A)

158522 Rhodia Inc. (1969?) Summary of MCPB Toxicology. Unpublished study. 3 p.

### 40 41578801 Tomerlin, J. (1990) Anticipated Residues and Dietary Exposure Anal

- ysis for MCPB on Peas. Unpublishe d study prepared by Technical Assessment Systems, Inc. 11 p.

47008601 Pigott, G. (2006) Phenoxy Herbicides: A Review of Studies with Aquatic Plants (MCPP

- p and 2,4 DP

- p). Unpublished study prepared by MCPP

- P Task Force. 33 p.

47163505 Harper, H. (2005) MCPA, 2,4

- D, Mecoprop, Dichlorprop, MCPB and 2,4

- DB: Validation of the Methodology for the Determination of Residue in Drinking and Surface Waters: Final Report. Project Number: TFT/005/052350. Unpublished study prepared by Huntingdon Research Cente r. 220 p.

92087999 Rhone

- Poulenc Ag Company (1990) Reregistration Phase 3 Response: Methyl

- 4

- chlorophenoxy)butyric acid. Correspondence and Supporting Material

### 41 

## Appendix C

**— SIP Results** 

Table 1. Inputs
Parameter Value
Chemical name MCPB Solubility (in water at 25 o C; mg/L) 100

Mammalian LD 50 (mg/kg

- bw) 912 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg

- bw) 7.5 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg

- bw) 282
Avian test species northern bobwhite quail Body weight (g) of "other" avian species Mineau scaling factor 1.15

Mallard NOAEC (mg/kg

- diet) 5000 Bobwhite quail NOAEC (mg/kg

- diet) 5000 NOAEC (mg/kg

- diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg

- diet) 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) 17.2000 17.2000 Adjusted toxicity value (mg/kg

- bw) 701.4744 5.7687 Ratio of exposure to toxicity 0.0245 2.9816 Conclusion* Drinking water exposure alone is NOT a potential

concern for mammals Exposure through drinking water alone is a potential

concern for mammals

Table 3. Avian Results
Parameter Acute Chronic Upper bound exposure (mg/kg

- bw) 81.0000 81.0000 Adjusted toxicity value (mg/kg

- bw) 203.1611 248.0628 Ratio of exposure to acute toxicity 0.3987 0.3265

### 42 Conclusion* Exposure through drinking water alone is a potential concern for birds Drinking water exposure alone is NOT a potential concern for birds

*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.

### 43 

## APPENDIX **D**

**— STIR Results**  

## Input

Application and Chemical Information

Enter Chemical Name MCPB
Enter Chemical Use Peas Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) air Enter Chemical Molecular Weight (g/mole) 228.6 Enter Chemical Vapor Pressure (mmHg) 4.00E

- 07 Enter Application Rate (lb a.i./acre) 1.6

Toxicity Properties

**Bird**
Enter Lowest Bird Oral LD 50 (mg/kg bw) 282 Enter Mineau Scaling Factor 1.15
Enter Tested Bird Weight (kg) 0.178
**Mammal**
Enter Lowest Rat Oral LD 50 (mg/kg bw) 912
Enter Lowest Rat Inhalation LC 50 (mg/L) 1.14 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35



## Output
Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 4.92E

- 03
Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 6.19E

- 04
Adjusted Inhalation LD 50 1.97E+00
Ratio of Vapor Dose to Adjusted Inhalation LD 50 3.15E

- 04 Exposure not Likely Significant
Maximum Post

- treatment Spray Inhalation Dose (mg/kg) 1.54E

- 01 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 7.82E

- 02 Exposure not Likely Significant



### Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 4.92E

- 03
Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 7.78E

- 04
Adjusted Inhalation LD 50 6.79E+01 Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.15E

- 05 Exposure not Likely Significant
Maximum Post

- treatment Spray Inhalation Dose (mg/kg) 1.93E

- 01 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 2.85E

- 03 Exposure not Likely Significant

### 44 

## APPENDIX E

**— ECOSAR (v. 1.0) Results** 

96

- hr Fish LC 50

Chemical Neutral Organics Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 84.011*

- - - - MCPB sodium 20772.877

- - - - MCPA 539.179

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 263.349

- - - -

2

- 4

- dihyroxyphenyl formate

- - 28.458 316.496

-

o

- cresol

- 14.568

- 74.103

- 4CC

- 6.480

- 27.832

-
5

- Chlorosalicylaldehyde

- 7.782

- 99.893 4.338

4

- Chloro

- 2

- methylanisole 9.290

- - - -

14

- d Fish LC 50

Chemical Neutral Organics Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 87.027*

- - - - MCPB sodium 20236.484

- - - - MCPA 549.760

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 269.982

- - - -

2

- 4

- dihyroxyphenyl formate

- - - - -

o

- cresol

- 74.684

- - - 4CC

- 26.961

- - -
5

- Chlorosalicylaldehyde

- 32.939

- - -
4

- Chloro

- 2

- methylanisole 9.587

- - - -

48

- hr Daphnid LC 50

Chemical Neutral Organics

Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 59.153*

- - - - MCPB sodium 8326.676

- - - - MCPA 328.535

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 168.576

- - - -

2

- 4

- dihyroxyphenyl formate

- - 157.345 171.713

-

o

- cresol

- 5.229

- 43.071

- 4CC

- 2.974

- 17.488

-

### 45 5

- Chlorosalicylaldehyde

- 3.499

- 21.160 5.066

4

- Chloro

- 2

- methylanisole 6.317

- - - -

96

- hr Green Algae EC 50

Chemical Neutral Organics

Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 53.913*

- - - - MCPB sodium 1450.214

- - - - MCPA 195.339

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 116.134

- - - -

2

- 4

- dihyroxyphenyl formate

- - 1.436 60.056

-

o

- cresol

- 23.911

- 19.033

- 4CC

- 12.772

- 10.067

-
5

- Chlorosalicylaldehyde

- 15.108

- 11.918 9.720

4

- Chloro

- 2

- methylanisole 5.195

- - - -

96

- hr Fish (SW) LC 50

Chemical Neutral Organics Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 104.199*

- - - - MCPB sodium 34418.113

- - - - MCPA 720.565*

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 343.026

- - - -

2

- 4

- dihyroxyphenyl formate

- - - - -

o

- cresol

- 10.326

- - - 4CC

- 3.106

- - -
5

- Chlorosalicylaldehyde

- 3.852

- - -
4

- Chloro

- 2

- methylanisole 11.732

- - - -

96

- hr Mysid Shrimp LC 50

Chemical Neutral Organics Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 28.692*

- - - - MCPB sodium 1.08e+005*

- - - - MCPA 371.054

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 142.435

- - - -

2

- 4

- dihyroxyphenyl formate

- - - - -

o

- cresol

- - - - - 4CC

- - - - -

### 46 5

- Chlorosalicylaldehyde

- - - - - 4

- Chloro

- 2

- methylanisole 3.756

- - - -

14

- d Earthworm LC 50

Chemical Neutral Organics Acid Phenols Phenols, Poly Neutral Organic SAR

(Baseline Toxicity) Aldehydes (Mono)

MCPB 2777.442*

- - - - MCPB sodium 756.321

- - - - MCPA 3080.735

- - - - 4

- (4

- hydroxy

- o

- tolyloxy) butyric acid 2751.554

- - - -

2

- 4

- dihyroxyphenyl formate

- - - - -

o

- cresol

- 94.933

- - - 4CC

- 68.229

- - -
5

- Chlorosalicylaldehyde

- 78.761

- - -
4

- Chloro

- 2

- methylanisole 201.268*

- - - -