United States Prevention, Pesticides EPA-738-R-06-031 Environmental Protection And Toxic Substances August 2006 Agency (7508P)

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# Interim Reregistration Eligibility Decision



# Carbofuran

List [A]

Case No. 0101

# Interim Reregistration Eligibility Decision (IRED)

Document for Carbofuran

Approved by: Debra Edwards, Ph. D.

Director Special Review and Reregistration Division

Date: August 3, 2006

## Table of Contents

Carbofuran Interim Reregistra tion Eligibility Decision Team ............................................ i Glossary of Terms and Abbreviations ................................................................................ ii

I. Introduction ................................................................................................................. 1

II. Chemical Overview ................................................................................................ 2

A. Regulatory History .................................................................................................. 2

B. Chemical Identification ........................................................................................... 3

C. Use Profile .......................................................................................................... 4

D. Estimated Usage of Pesticide .................................................................................. 5

III. Summary of Carbofuran Risk Assessments ........................................................... 5

A. Human Health Risk Assessment ............................................................................. 5

1. Toxicity of Carbofuran ....................................................................................... 5

2. Dietary Exposure and Risk from Food and Water ............................................. 9

3. Residential and Other Non-occupational Risk .................................................. 12

4. Aggregate Exposure and Risk ........................................................................... 12

5. Occupational Exposure and Risk ...................................................................... 13

6. Smoker Assessment .......................................................................................... 17

7. Human Incident Data ........................................................................................ 17

B. Environmental Risk Assessment ........................................................................... 18

1. Environmental Fate and Transport .................................................................... 20

2. Ecological Risk Estimation ............................................................................... 20

a. Terrestrial Organisms .................................................................................... 20 i) Birds .......................................................................................................... 20 ii) Mammals................................................................................................... 22 iii) Non-target insects ................................................................................. 23

b. Aquatic Organisms ........................................................................................ 24 i) Freshwater and Estuarine/Marine Fish ..................................................... 25 ii) Freshwater and Estuarine/Marine Invertebrates ....................................... 26

3. Risk Characterization ........................................................................................ 28

4. Endangered Species Considerations ................................................................. 29

IV. Interim Risk Management, Reregistration, and Tolerance Reassessment Decision

29

A. Determination of Reregistration Eligibility ...................................................... 29

B. Public Comments and Responses ........................................................................ 30

C. Regulatory Position Under FIFRA and FFDCA ................................................... 30

1. Mitigation Summary ......................................................................................... 31

2. Regulatory Rationale ........................................................................................ 31

3. Significance of Use ........................................................................................... 33

D. Endangered Species Considerations ..................................................................... 35

E. Food Quality Protection Act Fi ndings and Tolerance Summary .......................... 36

1. FQPA ................................................................................................................ 36

a. Risk Cup Determination ............................................................................... 36

b. Endocrine Disruptor Effects ......................................................................... 37

2. Interim Tolerance Summary ............................................................................. 37

### Carbofuran Interim Reregistration Eligibility Decision Team

Office of Pesticide Programs:

Biological and Economic Analysis Assessment

David Brassard Angel Chiri

David Donaldson

Jin Kim

Andrew Lee Stephen Smearman TJ Wyatt
Nicole Zinn

Environmental Fate and Effects Risk Assessment

Edward Fite

Edward Odenkirchin Melissa Panger

Donna Randall Christopher Salice Dirk Young

Health Effects Risk Assessment

Danette Drew
John Liccione

Susan Stanton Stephen Weiss

Registration Support

Rita Kumar

Risk Management

Stephanie Plummer

Laura Parsons

i

### Glossary of Terms and Abbreviations

AGDCI Agricultural Data Call-In ai Active Ingredient aPAD Acute Population Adjusted Dose AR Anticipated Residue

BCF Bioconcentration Factor

BMD Benchmark Dose CFR Code of Federal Regulations cPAD Chronic Population Adjusted Dose

CSF Confidential Statement of Formula CSFII USDA Continuing Survey s for Food Intake by Individuals

DCI Data Call-In DEEM Dietary Exposure Evaluation Model

EC Emulsifiable Concentrate Formulation EDWC Estimated Drinking Water Concentration

EEC Estimated Environmental Concentration EPA Environmental Protection Agency

EUP End-Use Product FCID Food Commodity Intake Database FDA Food and Drug Administration FIFRA Federal Insecticide, Fungicide, and Rodenticide Act FFDCA Federal Food, Drug, and Cosmetic Act FQPA Food Quality Protection Act FOB Functional Observation Battery

G Granular Formulation GENEEC Tier I Surface Water Computer Model

GLN Guideline Number HAFT Highest Average Field Trial

IR Index Reservoir

LC 50 Median Lethal Concentration. A statistically derived concentration of a substance that can be expected to cause death in 50% of test animals. It is usually expresse d as the weight of substance per weight or volume of water, air or feed, e.g., mg/l, mg/kg or ppm.

LD50 Median Lethal Dose. A statis tically derived single dose that can be expected to cause death in 50% of the test animals when administered by the route indicated (o ral, dermal, inhalation). It is expressed as a weight of substan ce per unit weight of animal, e.g., mg/kg.

LOC Level of Concern

LOD Limit of Detection

LOAEL Lowest Observed Adverse Effect Level MATC Maximum Acceptable Toxicant Concentration

Φ g/g Micrograms Per Gram

Φ g/L Micrograms Per Liter mg/kg/day Milligram Per Kilogram Per Day

iimg/L Milligrams Per Liter MOE Margin of Exposure

MRID Master Record Identification (number). EPA's system of recording and tracking studies submitted. MUP Manufacturing-Use Product NA Not Applicable NAWQA USGS National Water Quality Assessment NPDES National Pollutant Discharge Elimination System NR Not Required

NOAEL No Observed Adverse Effect Level OP Organophosphate OPP EPA Office of Pesticide Programs OPPTS EPA Office of Prevention, Pe sticides and Toxic Substances PAD Population Adjusted Dose PCA Percent Crop Area PDP USDA Pesticide Data Program PHED Pesticide Handler's Exposure Data

PHI Preharvest Interval ppb Parts Per Billion PPE Personal Protective Equipment ppm Parts Per Million PRZM/EXAMS Tier II Surface Water Computer Model Q 1 * The Carcinogenic Potential of a Compound, Quantified by the

EPA's Cancer Risk Model RAC Raw Agriculture Commodity RED Reregistration Eligibility Decision REI Restricted Entry Interval

RfD Reference Dose RQ Risk Quotient SCI-GROW Tier I Ground Water Computer Model SAP Science Advisory Panel SF Safety Factor SLC Single Layer Clothing SLN Special Local Need (Registrat ions Under Section 24(c) of FIFRA) TAF Toxicity Adjustment Factor TCPSA 2,3,3-trichloroprop-2-ene sulfoni c acid (nitrapyrin Metabolite) TGAI Technical Grade Active Ingredient

TRR Total Radioactive Residue USDA United States Department of Agriculture USGS United States Geological Survey UF Uncertainty Factor

UV Ultraviolet

WPS Worker Protection Standard

iiiI. Introduction

The Federal Insecticide, Fungicide, a nd Rodenticide Act (FIFRA) was amended in 1988 to accelerate the reregistration of produc ts with active ingredients registered prior to November 1, 1984. The amended Act calls for the development and submission of data to support the reregistra tion of an active ingredient, as well as a review of all submitted data by the U.S. Environmental Protection Agency (hereafter referred to as EPA or the Agency). Reregistration involves a thorough review of the scientific database underlying a pesticide's registra tion. The purpose of the Agency's review is to reassess the potential risks arising from the currently registered uses of the pesticide, to determine

the need for additional data on health and environmental effects, and to determine whether or not the pesticide meets the "no unreasonable adverse effects" criteria of

FIFRA.

On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was signed into law. This Act amends FIFRA to require reassessment of all tolerances in effect on the day before it was enacted by August 2006. EPA decided that, for those chemicals that have tolerances and are undergoing rere gistration, tolerance reassessment will be accomplished through the reregistration process. FQPA also amended the Federal Food, Drug, and Cosmetic Act (FFDCA) to require a safety finding in tolerance reassessment

based on factors that include an assessment of cumulative effects of chemicals with a common mechanism of toxicity. The reason for consideration of other substances is that the possibility exists that low-level exposures to multiple chemicals that cause a common

toxic effect lead to the same adverse health effect as would a hi gh level of exposure to any one of the other substances individually.

As mentioned above, FQPA requires EPA to consider "available information" concerning the cumulative effects of a part icular pesticide's residues and "other

substances that have a common mechanism of toxicity" when considering whether to establish, modify, or revoke a tolerance. Carbofuran is a member of the N-methyl carbamate (NMC) class of pes ticides. This class also includes carbaryl, aldicarb, methomyl, and oxamyl, among others. The NMCs, as a group, have been determined to share a common mechanism of toxicity (Jul y 2001 memo from Office Director Marcia Mulkey). The preliminary cumulative risk assessment (CRA) for the NMC cumulative Assessment Group, which includes carbofuran, wa s released in July 2005. The revised CRA is currently being developed and will be completed during 2006. The results of this NMC cumulative assessment, as well as the single chemical carbofuran assessment, will be considered during the carbof uran reregistration process in which decisions regarding establishing, modifying, or revoking car bofuran tolerances will be made.

This document presents EPA’s revised human health and ecological risk assessments and its progress toward tolerance reassessment, and the interim reregistration eligibility

decision for carbofuran. The document consists of six s ections: section I contains the regulatory framework for reregistration/tole rance reassessment; section II provides a profile of the use and usage of the chemical; section III give s an overview of the revised

1human health and environmental effects risk assessments based on data, public comments, and other information received in response to the preliminary risk assessments, section IV presents the Agen cy’s reregistration eligibility, tolerance reassessment, and risk management decisions; section V summarizes label changes necessary to implement the risk mitigation m easures outlined in Section IV; and section VI provides information on how to access re lated documents. Finally, the Appendices list related and supporting docum ents and Data Call-In (DCI) information. The revised

risk assessment documents and related addenda are not included in this document, but are

available in the Public Docket under docket number EPA-HQ-OPP-2005-0162.

II. Chemical Overview

A. Regulatory History

Carbofuran is a broad spectrum N-methyl carbamate insecticide and nematicide registered for control of soil and foliar pest s on a variety of field, fruit, and vegetable crops. It was first registered in the United States in 1969. Through an agreement between EPA and the technical registrant in 1991, granular carbofuran has been limited to the sale of 2,500 lbs of active ingredient per year in the U.S. since 1994, for use only on certain crops. Today granular carbofuran is limited to use on spinach grown for seed, pine seedlings, bananas (in Hawaii only), and cu curbits only. Carbofuran is classified as a restricted use pesticide.

In the late 1990s, the techni cal registrant made a number of changes to labels in order to reduce drinking wate r and ecological risks of concern. These included reducing application rates and numbers of applications for alfalfa, co tton, corn, potatoes, soybeans, sugarcane, and sunflowers. Numbers of applicat ions were also restricted on some soils to reduce groundwater concentrations.

Three human studies have been conducte d for carbofuran – one oral and two dermal. Since the 1990s, the Agency has cons idered the appropriate ness of these studies for risk assessment purposes several times. Most recently, these studies were reviewed by the Agency’s Human Studies Review Board (HSRB) in May 2006. The HSRB concluded that, while informative, the studies are not appropriate for use by the Agency

in either the individual car bofuran or N-methyl carbamate cumulative risk assessment. This decision was based upon the following, for all three studies: sma ll sample size, lack of control subjects, and highly variable result s for red blood cell cholin esterase activity. Additionally, the board had con cerns regarding inappropriate application methods in the

dermal studies and also determined that the conduct of the dermal studies was unethical.

There are currently one technical, tw o manufacturing-use, and six end-use products registered under Section 3 of the Fede ral Insecticide, Fungi cide and Rodenticide Act (FIFRA). There are also 77 active Speci al Local Need registrations under Section 24(c) of FIFRA. This Interim Reregistra tion Eligibility Decision document evaluates risks from all currently registered uses.

2EPA followed a 6-phase public participat ion process in developing this interim

decision. This means that there were tw o 60-day public comment periods on the risk

assessments. EPA released the revised human health and ecological risk assessments for the second phase of public comment (Phase 5) on March 22, 2006. This IRED document will be posted in the carbofuran reregist ration docket, along with any revised risk assessments and responses to public comments received.

B. Chemical Identification

Chemical Structure:

Common Name: Carbofuran

Chemical Name: 2,3-dihydro-2,2-dimethyl-7-ben zofuranyl-N-methylcarbamate

Chemical Family: N-methyl Carbamate

Empirical Formula: C 12 H 15 NO 3

CAS Registry Number: 1563-66-2

Case Number: 0101

OPP Chemical Code: 090601

Molecular weight: 221.3

Trade Names: Furadan

Basic Manufacturers: FMC Corporation

Carbofuran is an odorless, white, crystal line solid with a melting point range of

150-154 o C. It is slightly soluble in wate r, and is highly solu ble in N-methyl-2- pyrrolidone, dimethylformamide, dimethyl sulfoxide, acetone, acetonitrile, methylene

3chloride, cyclohexanone, benzene, and xylene. Carbofuran is stab le under neutral and acidic conditions, but decompos es under alkaline conditions.

C. Use Profile

The following is information on the curre ntly registered uses of carbofuran, including an overview of use sites and application methods.

Type of Pesticide: Restricted use systemic insecticide

Summary of Use: Used for control of a variety of insect pests on a variety of field, fruit, and vegetable crops. Carbofuran is not used in residential settings or fo od-handling establishments.

Food uses : Registered for use on the following crops/sites:

Alfalfa, artichoke, banana, barley, coffee, co rn (field, pop, and sweet ), cotton, cucurbits (cucumber, melons, and squash), grapes , oats, pepper, plantain, potato, sorghum, soybean, sugar beet, sugarcane, sunflower, and wheat

Non-food uses :

Agricultural fallow land, cotton, ornamental a nd/or shade trees, ornamental herbaceous plants, ornamental non-flowering plants, or namental woody shrubs and vines, pine, spinach grown for seed, and tobacco

Target Pests: Alfalfa weevil, aphids, bana na root borer, Colorado potato beetle, corn rootworm, cribrate weevil, cucumber beetles, European corn borer, flea beetles, grasshoppers, leafhoppers, nematodes, potato tuberworms, Southwestern corn borer, thrips, wireworms

Formulation Types: Granular and flowable

Method and Rates of Application:

Application Methods: Foliar, soil, seedling dip

Application Equipment: Aerial equipment, chemigation systems,groundboom sprayers, airblast sprayers, tractordrawn spreaders, and handheld equipment.

Application Rates: Application rates range from 0.19 (agricultural fallow land) to 10 lbs a.i. /A (grapes and potatoes), depending on the application scenario.

4Application Timing: At plant, post-plant

Use Classification: Restricted

D. Estimated Usage of Pesticide

The estimate for total domestic use (a nnual average) of carbofuran is nearly 1 million pounds of active ingredient for the liqui d formulation, with the majority of use occurring on the following crops: corn, alfa lfa, and potatoes. U nder the existing terms and conditions of the registration, sale of the granular formulation is limited to 2,500 pounds active ingredient per year, and use is limited to pine seedlings, cucurbits, bananas (in Hawaii only), and spinach grown for seed.

III. Summary of Carbofuran Risk Assessments

The purpose of this summary is to assist the reader by identifying the key features and findings of these risk assessments, a nd to help the reader better understand the conclusions reached in the assessments. The human health and ecological risk assessments form the basis of interim regulat ory decisions for carbofuran. While the risk assessments and related addenda are not included in this document, they are available

from the OPP Public Docket EPA- HQ-OPP-2005-0261 and may be accessed on the

internet at http://www.regulations.gov

.

A. Human Health Risk Assessment

1. Toxicity of Carbofuran

Table 1. Acute Toxicity of Carbofuran

Guideline No./ Study Type Species MRID No. Results Toxicity Category

870.1100 Acute oral toxicity Rat Gronning and Kimmerle, 1974 LD50 = 7.8 mg/kg

_ 6.0 mg/kg

_ I

870.1200 Acute dermal toxicity Rabbit 44671601 LD50 = 4403 (2900 - 6685) mg/kg - intact skin III

870.1300 Acute inhalation toxicity Rat Gronning and Kimmerle, 1974 LC 50 = 0.08 mg/L I

870.2400 Acute eye irritation Rabbit 00070347 Minimal irritation III

870.2500 Primary dermal

irritation Rabbit 00054336 Primary Irritation Score =

0.25 IV

870.2600 Skin sensitization Guinea pig 44827101 Non sensitizer N/A

5Animal toxicity studies show that, as with other N-methyl carbamate pesticides,

the critical effect of carbof uran for various exposure durations is cholinesterase inhibition. Similar to other N-methyl carba mate pesticides, inhibition is followed by rapid recovery of cholinesterase.

The toxicology database is considered to be adequate for se lection of endpoints

for risk assessment.

EPA considered a human oral study as pa rt of its deliberations; however, due to serious scientific limitations, EPA has not in cluded it in the carbofuran risk assessment that supports the reregistration decision outlined in this document. The results of the rat comparative ChE study are considered to be the most suitable for risk assessment

purposes.

Developmental toxicity st udies in both the rat and ra bbit show no evidence of quantitative or qualitativ e increased susceptibility of th e developing fetuses. There was evidence of qualitative increased susceptib ility in the rat multi- generation reproduction study since offspring toxicity was manifested as decreased pup survival between birth and post natal day (PND) 4, whereas parent al toxicity was limited to decreased body weight gain.

The rat developmental neurotoxicity study also provided evidence of a qualitative increase in offspring susceptibility. At the lowest observed adverse effects level (LOAEL) of 75 ppm, maternal toxicity was manifested as decreased body weight gain and food consumption, whereas offspring toxi city at this dose was manifested as increased mortality, decreased pup viab ility, and decreased fetal weight.

Carbofuran is primarily metabolized into three phenolic carbamate metabolites and into 3-hydroxy carbofuran. The trio of phe nolic metabolites is not deemed to be of toxicological significance. For risk a ssessment purposes, 3-hydroxycarbofuran is considered to be of equal t oxicity as parent carbofuran.

FQPA Safety Factor

The FQPA Safety Factor (as mandated by the Food Quality Protection Act of 1996) is intended to provide up to an additiona l 10-fold safety factor (10X), to account for potential pre- and post-natal toxicity a nd completeness of the data with respect to exposure (food, water, and non-occupational) and toxicity to infants and children. In the case of carbofuran, there was no evidence of e ither quantitative or qualitative increased susceptibility of fetus/pups in the rat or rabbi t developmental toxicity studies. There was evidence of qualitative increased susceptib ility in the rat multi- generation reproduction study and the rat developmental neurotoxicity study. BMD (benchmark dose) analyses of the comparative ChE rat study revealed that the BMD values for the PND11 pups were lower (i.e., more sensitive) than those of a dult rats. The Agency has retained a FQPA factor (for database uncertainties) in the deri vation of the carbofuranacute PAD, which is based on brain ChE inhibition in rat pups. Th e magnitude of this factor is 5X. This

6factor was based on the following rationale: the comparative ChE rat study measured only brain ChE inhibition, red bl ood cell (RBC) ChE inhibition in adult rats is the more sensitive endpoint; there is an observed 5-fo ld difference between brain ChE inhibition and RBC ChE inhibition in adult rats; and the as sumption is made that for rat pups, there

will be a similar 5-fold difference in RBC vs. brain ChE inhibition. See also the discussion below under “Endpoints se lected for risk assessment.”

Cancer Classification

Carbofuran does not appear to possess mutagenic activity and was negative in both rat and mouse oncogenicity assays. Carbofuran is classified as a "Not likely" human carcinogen based on the lack of evidence of carcinogenicity in mice or rats.

Endpoints selected for risk assessment

There are several studies available whic h measured acute ChE inhibition at or near the peak time of inhibition (15 to 45 minut es), and which the Agency was able to use

to determine the derivation of the acute RfD and acute PAD. These include two studies performed by the registrant: 1) a time course study in which male and female rats were dosed at 0.5 and 1.0 mg/kg, and 2) a compar ative ChE study where adult and juvenile (PND11) rats were dosed at 0.3, 0.6, and 1.0 mg/kg. A third ChE study was performed in support of the Agency’s cumulative risk assessm ent for the N-methyl carbamates. In this study, scientists from the USEPA National He alth and Environmenta l Effects Research Laboratory (NHEERL) performed dose-response studies in male rats, where brain and RBC ChE inhibition, along with motor activit y, were measured. This study included doses of carbofuran ranging from 0.1 mg/kg to 1.5 mg/kg.

The risk assessment for carbofuran is based on BMD values, rather than No Observed Adverse Effect Level (NOAEL) or LOAEL values. The Agency used this

method because NOAELs and LOAELs do not nece ssarily offer the best characterization between dose and response for a given chemical, and are often limited by dose selection. In order to evaluate the appropriate poin t of departure (PoD) for ChE inhibition, EPA performed a BMD analysis using the availabl e comparative cholines terase study in rats (the most sensitive species).

The dose at which 10% ChE inhibition is observed (BMD 10 ) and the lower 95% confidence intervals (BMDL 10 ) were estimated from the comparative cholinesterase study. The BMD 10 was selected because it is generall y at or near the limit of sensitivity for discerning a statistically significant decrease in Ch E activity across the blood and brain compartments, and is a response level close to the background ChE. Moreover, the Agency believes that 10% is likely to be prot ective to other toxicitie s, such as clinical signs and/or beha vioral endpoints.

The BMDL 10 of 0.03 mg/kg/day for inhibition of ChE in the brain of PND11 male pups was selected for derivation of the acute RfD. The following uncertainty factors were applied: 5X FQPA safety factor base d on database uncertainties, 10X for variability

7among individuals, and 10X for interspecies extrapolation. The resulting aPAD for the general population a nd all population subgr oups is 0.00006 mg/kg/day.

The Agency’s analysis of the brain ChE inhibition data from the comparative ChE study suggests that PND 11 pups are 2.5X more sensitive than adults (0.11 mg/kg and 0.12 mg/kg for male and female adult ra ts, respectively, as compared to 0.04 mg/kg and 0.05 mg/kg for male and female PND11 rats, respectively). In addition, the following uncertainties exist: 1) RBC ChE i nhibition may be a more sensitive endpoint compared to brain ChE; 2) pups appear to be more sensitive than adult rats; and 3) due to the lack of reliable RBC data in pups, ther e is residual uncertainty in the available toxicology database. Given these uncertainti es, the Agency has retained a 5X FQPA safety factor in the derivation of the carbofuran acute RfD. Due to the fact that the RfD

is based on a BMDL 10 in rat pups, there is no need to account for the 2.5X sensitivity observed in pups vs. adults.

A chronic RfD was not selected because the acute RfD is considered protective of chronic exposures, given that carbofuran-induced inhi bition of ChE activity is reversible (within 24 hours). The longer-term exposures could be considered a series of
acute exposures.

Table 2. Toxicity Endpoints for Human Health Risk Assessment for Carbofuran

Exposure
Scenario Dose Used in Risk Assessment,

UF FQPA SF and Endpoint

for Risk Assessment Study and Toxicological Effects

Acute Dietary All Populations BMDL 10 = 0.03 mg/kg/day

UF = 500

Acute RfD = 0.00006 mg/kg/day FQPA SF = 5X

aPAD = 0.00006 mg/kg/day Comparative ChE Study

BMDL 10 = 0.03 mg/kg/day, based on

cholinesterase inhibition in the brain of postnatal day 11 (PND11) male

pups.

Short, Intermediate and Long-Term Dermal

(Occupational) BMDL 10 = 0.01 mg/kg/day

UF=100 Dermal absorption rate (rat dermal study) = 6% MOE ≥ 100 does not

exceed level of concern Special ChE Study (USEPA 2005)

BMDL 10 = 0.01 mg/kg/day, based on

RBC cholinesterase inhibition in adult

rat

Short, Intermediate and Long-Term Inhalation (Occupational) BMDL 10 = 0.01 mg/kg/day

UF=100 Inhalation absorption rate =

100% MOE > 100 does not

exceed level of concern Special ChE Study (USEPA 2005)

BMDL 10 = 0.01 mg/kg/day, based on

RBC cholinesterase inhibition in adult

rat

Cancer (oral, dermal, inhalation) "Not likely" Risk assessment not required

82. Dietary Exposure and Risk from Food and Water

A refined (Tier 3) acute probabilistic dietary risk assessment was conducted using DEEM-FCIDTM, Version 2.02, which in corporates consumption data from USDA’s CSFII, 1994-1996 and 1998, as well as monitoring data from PDP and the FDA Surveillance Monitoring Program, estimated percent crop treated information, and processing/cooking factors, where applicable. EPA has determined that, because of the rapid reversibility of cholinesterase inhibi tion related to carbofuran, the acute dietary assessment would be protective of any chroni c exposures in the diet. Therefore, a separate chronic dietary exposure assessm ent was not conducted. Exposure estimates are reported in milligrams per kilogram of body weight per day, and risk is expressed as a percent of the aPAD. Exposure estimates that are less than 100% of the PAD are

below the EPA’s level of concern.

Combined anticipated residues of carbofuran and 3-hydroxycarbofuran on food

were included in the acute assessment. Acute anticip ated residues for many foods (artichoke, cucumber, melons, milk, peppers, potatoes, pumpkin, squash, strawberry and sweet corn) were derived using USDA Pestic ide Data Program (P DP) monitoring data from recent years (through 2003 for all co mmodities except milk, for which recently available 2004 data were used). For artic hokes, PDP data for peppers were used as surrogate data. Anticipated residues for bananas and grapes were derived using monitoring data from the 2000 Carbamate Market Basket Survey. Most of the samples analyzed by the PDP and the Carbamate Market Basket Survey Task Force contained no

detectable residues of carbofur an or its 3-hydroxy metabolite.

A value equal to 1⁄2 the combined limits of detection (LODs) of carbofuran and 3- hydroxycarbofuran was assumed for samples w ith non-detectable residues, with zeros incorporated to account for the percent of the crop not treated with carbofuran. For commodities with no monitoring data availa ble (cranberries, coffee, sugar beets, sugarcane and sunflowers) and for field cr ops that are typically blended prior to marketing (barley, field corn, oats, rice, s oybean, and wheat), anticipated residues were based on field trial data. Although PDP data are generally assumed to provide more refined estimates of exposure than field tr ial data, they may sometimes overestimate exposure, particularly for blended commoditie s, such as those listed above, with low percent crop treated estimate s, no detections in the PDP data and relatively high 1⁄2 LOD values. Therefore, field trial data were us ed, with adjustments fo r percent cr op treated, to provide more refined exposure estimate s for these commodities. Exposure estimates are reported in milligrams per kilogram of body weight per day, and risk is expressed as a percent of the aPAD. Exposure estimates that are less than 100% of the aPAD are

below the EPA’s level of concern.

The estimated acute dietary (food only) exposure exceeds the Agency’s level of concern for the U.S. population and all reported population subgroups at the 99.9th percentile of exposure. Carbofuran diet ary exposure at the 99.9th percentile was estimated at 0.000154 mg/kg/day for the U.S. population (260% of the aPAD) and

90.000292 mg/kg/day (490% of the aPAD) for children 1-2 ye ars old, the population subgroup with the highest estimated diet ary exposure. See Table 3 below.

Table 3. Summary of Acute Dietary Exposur e and Risk for Carbofuran for Food Alone (aPAD = 0.00006 mg/kg/day) at 99.9 th Percentile of Exposure
Population Subgroup Dietary Exposure (mg/kg/day) % aPAD General US Population 0.000154 260
Infants < 1 year 0.000182 300
Children 1-2 years old 0.000292 490 Children 3-5 years old 0.000290 480

Surface Water Estimated Drinking Water Concentrations

For surface water, estimated environm ental drinking water concentrations (EDWCs) were calculated using the PRZM/E XAMS model. If appropriate, regional percent cropped area factors (PCA) were considered. ED WCs represent the range of concentrations that are expected to result from the annual use of carbofuran over a 30- year period at lowest and maximum application rates in different growing areas nationally, and vary over several orders of magnitude across use areas. Only acute values are presented here since the Agency di d not assess chronic or cancer dietary risks for carbofuran. For an in-depth discussion of modeling and the ra nge of values, please see the carbofuran drinking water assessment.

Table 4. Acute EDWCs (ppb) for Carbof uran on Selected Agricultural Crops. (Ranges of acute concentrations base d on a distribution of default PCAs.)

Location/Crop Using Lowest Label Rate 1 Using Highest Label Rate 1

Potato 0.25-3.1 1.6-20 CA Grape 0.4 4.3

Alfalfa 0.13-1.5 1.1-12

Alfalfa 0.11-1.2 0.86-10

ID Potato
-- 10

Tobacco 8-17 12-26

Cotton 14-18 57-72

Corn 19-36 26-49 Sorghum 2.4-7.8 23-75 1. One-in-ten-year annual peak concentration

3-Hydroxycarbofuran has not been s hown to form in the majority of environmental fate studies, with the excepti on of one study in whic h it was detected in low amounts as a result of soil photolysis. Therefore, 3-hydroxycarbofuran was not included in the Agency’s human drinking wa ter exposure assessment. While estimation of potential exposure to 3-hydroxycarbofuran remains an uncertainty in the human drinking water assessment, it is not expected to significantl y add to exposure estimates (maximum concentrations in monitoring were approximately 6% of carbofuran concentrations).

10Groundwater Estimated Drinking Water Concentrations

Estimation of carbofuran in groundwater was based on a study conducted by the registrant. Following detection of carbof uran in ground water in Long Island, NY, FMC voluntarily conducted a prospective groundwat er (PGW) monitoring study during 1981- 1983 near Salisbury, Maryland to assess impacts from the labeled use of carbofuran. Soils at the study site are sandy and promote leaching to groundwater. A corn plot had one application of Furadan 10G (totaling 3.0 lb s a.i./A; the labeled rate has since been reduced to 1 lbs a.i./A on corn for these soils).

Because this prospective ground wa ter study was conducted over only one growing season, the reported ground water conc entrations do not represent impacts from carbofuran use in multiple years. Thus, EPA used superpositioning techniques to provide estimates of concentrations following long-term (25 years) use of carbofuran at current label rates. These estimation techniques a ssumed chemical transformation processes and transport and interaction mechanisms are line ar with respect to c oncentration. Based on these assumptions, the carbofur an concentrations in groundwat er for various application rates were estimated (Table 5). EDWC s for ground water, estimated from PGW monitoring data, range from 1.4 ppb (low a pplication to alfalfa) to 110 ppb (high application to grapes).

Table 5. Estimated 90-day Average Concen trations of Carbofuran in Shallow Groundwater for a Range of Application Rates
Crop Application Rate (lbs a.i./A) Groundwater EDWCs (ppb)

Alfalfa 0.125 1.4

Cotton 0.25 2.8

Corn 1.0 11

Corn 2.0 22

Tobacco 4.0 44 Grapes 10.0 110

Water Monitoring Data

Available groundwater monitoring studies conducted in the 1980s at locations associated with carbofuran uses report p eak carbofuran concentrations ranging from 1.4- 176 ppb. Several studies reported peak concen trations in the 50 ppb range resulting from application rates comparable to currently used application rates. Non-targeted monitoring tends to show detections at lo wer concentrations, ra rely exceeding 1 ppb, although higher concentrations have been repo rted. Over the last decade, non-targeted ground water monitoring reports indicate fewer locations with detections. Consistent with its environmental fate pr operties, carbofuran has been de tected more frequently and at higher concentrations in acidic environm ents. The most vulnerable drinking water sites appear to be shallow private wells near carbofuran use areas, where the ground water has a lower pH.

11Only non-targeted monitoring data are available for surface water; consequently, detections cannot be directly associated with specific use sites or lo cations that are most

vulnerable to contamination. Few detections exceeding 1 ppb have been found since the

mid-1990s.

Detectable residues of carbofuran (no 3-hydroxycarbofuran found) were found in 14 out of 1418 PDP water samples (data from 2001-2003). Carbofuran residues ranged from 0.001 ppb to 0.079 ppb. These data were not deemed appropriate for use in risk assessment as the data may not be reflective of areas with significant carbofuran use and the community water systems sampled by PD P are generally deep ground water or surface water systems and do not include priv ate wells. Since th e highest carbofuran concentrations are likely to occur in shallow, private wells in areas where carbofuran is used, use of the PDP data would not be pr otective of people whos e drinking water comes

from such wells.

The Agency evaluated data from state, USGS and registrant monitoring programs.

The EPA Office of Water collected monito ring data for compliance with the Safe Drinking Water Act and in a 2002 report described levels of carbofuran found in 16 states in finished drinking water. No system exceeded the carbofuran MCL of 40 ppb; however, several systems exceed ed concentrations of 7 a nd 4 ppb. Because these data were collected for compliance purposes (i.e., not to determine acute exposures) they are not included directly into the risk calculati ons. Some forms of dr inking water treatment such as softening may reduce concentrations of carbofuran in finished water, but other

water treatment methods do not affect concentrations.

3. Residential and Other Non-occupational Risk

Carbofuran is a restricted use pesticide and is not registered for residential or other non-occupational uses. Therefore, no re sidential exposure and risk assessment was

conducted for carbofuran.

4. Aggregate Exposure and Risk

The Food Quality Protection Act (FQPA) amendments to the Federal Food, Drug and Cosmetic Act (FFDCA, Section 408(b)(2)(A) (iii) require “that th ere is a reasonable certainty that no harm will result from a ggregate exposure to the pesticide chemical residue, including all anticipa ted dietary exposures for which there is reliable information.” Aggregate exposure will typi cally include dietary exposures (food plus drinking water), residential uses of a pest icide, and other non-occupational sources of

exposure.

There are no residential uses of car bofuran. Therefore, when evaluating aggregate exposures, only the dietary pathwa ys of food and drinking water would be

relevant.

12Acute dietary exposure and risk from f ood alone exceeds the Agency’s level of concern (i.e., >100% aPAD). For the most highly exposed subpopulation (children 1-2 years old), the acute dietary (food only) risk estimate is 490% of the aPAD. For the general U.S. population, the acute dietary (food only) risk estimate is 260% of the aPAD.

Using the PRZM/EXAMS model, the acute EDWCs in surface water range from 0.11 ppb (low application rate to alfalfa) to 75 ppb (maximum label application rate to sorghum) for nine crop location scenario s. EDWCs for ground water, based on prospective ground water monitoring data, range from 1.4 ppb (low application to alfalfa) to 110 ppb (maximum application to grapes).

If one assumes that there are no acute di etary food exposures to carbofuran and all of the allowable exposure occurred through water sources (i.e., assuming the aPAD of 0.00006 mg/kg/day is completely allocated to ex posure to residues in water), the drinking water level of concern (DWLOC) would be 2.1 ppb for the general U.S. population and 0.6 ppb for infants and children. These values are based on daily water consumption

estimates of two liters for a dults and one liter for infant s and children. DWLOCs based on consumption of a single 8 ounce serving of water would be 2.6 ppb for infants and children and 18 ppb for adults. Therefore, ev en if all of the allowable dietary exposure (i.e., the entire aPAD or “risk cup”) occurred through a single serving of drinking water, the Agency would have concerns for acute exposure to carbofuran, particularly for individuals (both adults a nd children) who may derive their water from vulnerable watersheds that are highly cropped and where ca rbofuran applications may be made up to the maximum label rates. Exposure to individuals (adults) whose drinking water comes from sources where crop/location scenarios result in lower EDWCs (scenarios with lower applications) may not be of concern if the entire risk cup were available for water

exposures.

5. Occupational Exposure and Risk

Workers can be exposed to a pesticid e through mixing, loading, and/or applying a pesticide, or re-entering trea ted sites. Occupational risk is measured by a Margin of Exposure (MOE), which describes how close the occupational exposure comes to a point of departure (e.g., BMD or NOAEL). The ta rget MOE for carbofuran is 100, meaning that MOEs that fall below 100 indicate a possible need for mitigation.

Occupational handler scenarios were a ssessed using the short-term endpoint for dermal and inhalation exposures. The short- term dermal and inhalation endpoint is a

BMDL 10 of 0.01 mg/kg/day, based on red blood cell ChE inhibition in adult male rats. Additionally, a dermal absorption factor of 6% has been used, based on a 24-hour exposure duration from a dermal penetra tion study. The UF for both dermal and inhalation endpoints is 100 (10X for intraspe cies variability and 10X for interspecies extrapolation). Dermal and inhalation exposur es were combined to assess handler risk.

Occupational handler risk estimates have been assessed for short-term exposures. Intermediate-term and long-term exposures we re not assessed, as ChE inhibition does not

13increase with continued exposure to carbofuran and because of the ra pid reversibility of

ChE inhibition.

No chemical-specific data for assessing human exposures during pesticide handling activities were submitted, so short- term dermal and inhalation exposures for handlers were developed using the Pestic ide Handlers Exposure Database (PHED)

Version 1.1.

The Agency has determined that there ar e potential exposures to individuals who mix, load, apply, and otherwise handle ca rbofuran during the usual use patterns associated with the pesticide. Thirteen major occupational exposure scenarios were identified based on the type of equipment that potentially can be used to make carbofuran applications. These scenarios are listed in Table 6 below.

The calculations of short-term total risk s indicate that most occupational handler risks are above the Agency’s level of concer n (i.e., MOEs less th an 100), even at the maximum mitigation level (engineering cont rols) for all handler scenarios except mixing/loading granulars for tractor-drawn spr eader application (cuc urbits, spinach) and flagging for spray application (corn, suga rcane). Additionally, total MOEs for mixing/loading/applying liquids for applicati on to any crop via backpack sprayer were greater than 100 with baseline protection. Total MOEs for mixing/loading/applying liquids for low-pressure handwand applic ation were greater than 100 with PPE2 protection (single layer protec tion, gloves, and PF5 respirat or). Table 6 below shows MOEs for the remaining handler scenarios, which do not reach 100, even with engineering controls.

Table 6. Summary of Handler Scenarios Total (Dermal and Inhalation) MOEs with Engineering Controls (i.e., Maximum MOEs)

Exposure Scenario Crop Application Rate (lbs

a.i./A) Daily Area

Treated (Acres/day) Total

MOE

MIXER/LOADER Alfalfa, Corn (field and pop),

Cotton 1 lb 1200 0.96

Potatoes 2 lb 350 1.7 Sorghum 0.50 1200 2.0 Small grains (wheat, barley, oat), Soybeans 0.25 1200 3.9

Ag Fallow/Idle land 0.19 350 18 Corn (sweet), Sunflowers 0.50 350 6.8 Mixing/Loading Liquids for Aerial application

Sugarcane 0.75 350 4.4 Mixing/Loading Liquids for Chemigation application Grapes 6 350 0.56

Grapes 10 80 1.5

Ornamentals 10 40 2.9 Coffee (seedbeds) 6.90 80 2.1 Mixing/Loading Liquids for

Groundboom application Tobacco 6 80 2.4

14Exposure Scenario Crop Application Daily Area Total Rate (lbs Treated MOE

a.i./A) (Acres/day) Peppers 3 80 4.8 Sugar Beets 2 200 3.0

Sunflowers 1.40 80 10 Alfalfa, Corn (field and pop),

Cotton 1 200 6.0

Potatoes 3 80 4.8 Sugarcane 0.75 80 20 Sorghum 0.50 200 12 Corn (sweet) 1 80 15

Artichoke 1 80 15 Small grains (wheat, barley, oat), Soybeans 0.25 200 23

APPLICATOR Alfalfa, Corn (field and pop),

Cotton 1 1200 1.6

Potatoes 2 350 2.7 Sorghum 0.50 1200 3.2 Small grains (wheat, barley, oat), Soybeans 0.25 1200 6.4

Corn (sweet), Sunflowers 0.50 350 11 Ag Fallow/Idle land 0.19 350 29 Aerial application

Sugarcane 0.75 350 7.2 Grapes 10 80 2.6

Ornamentals 10 40 5.2 Coffee (seed beds) 6.90 80 3.2

Tobacco 6 80 4.4 Peppers 3 80 8.4 Sugar Beets 2 200 5.2

Sunflowers 1.40 80 18 Alfalfa, Corn (field and pop),

Cotton 1 200 10

Potatoes 3 80 8.4 Sugarcane 0.75 80 34 Sorghum 0.50 200 20 Corn (sweet) 1 80 26 Small grains (wheat, barley, oat), Soybeans 0.25 200 40 Groundboom application

Artichoke 1 80 26 Applying Granulars for

Tractor-drawn Spreaders application Cucurbits, spinach 0.50 80 52

FLAGGER

Potatoes 2 350 48 Sorghum 2 1200 14 Flagging for Spray application Small grains (wheat, barley, oat), Soybeans 2 1200 14

15The Agency did not assess risks to work ers mixing, loading or applying flowable carbofuran to pine seedlings as a slurry dip because there are no appropriate exposure

data to evaluate the risks at this time. In the absence of appropriate data, the exposure for dipping pine seedlings is considered to be less than or similar to exposures from handwand applications to ornamentals with regards to amount of product which could be handled. Total MOEs for mixing/loading/ap plying liquids for low-pressure handwand application were greater than 100 with single layer clothing, gloves, a nd a PF5 respirator. As a conservative measure, this level of prot ective clothing will be required for flowable carbofuran use on pine seedlings.

Postapplication Occupational Risk

For workers entering a treated site, restricted entry inte rvals (REIs) are calculated to determine the minimum length of time require d before workers can safely reenter (i.e.,

MOEs ≥ 100). Many of the registered uses of car bofuran involve applications to the soil only and do not result in treatmen t of plant foliage. Therefor e, these scenarios were not included in the postapplication risk assessment. However, multiple applications of sprays to foliage may occur for a number of crops. EPA expects harvesting for all these particular crops to be fully mechanized.

For those crops for which postapplicati on exposures are expected to occur, exposure was estimated using dislodgeable foliar residue (DFR) data for carbofuran applied to corn, cotton, and potatoes. MOEs failed to reach 100 within the currently prescribed REIs for most of these crops.

Short-term exposures may occur for se veral crops requiring reentry by crop advisors. Such exposures also may occu r for field workers involved in irrigation activities, early season hoeing and thinning, and de-tasseling corn grown for seed.

A 14-day restricted entry in terval is specified on curre nt carbofuran labeling for foliar application to corn, s unflowers, and sorghum. A 48-hour REI is specified on product labels for all other crops, based on the acute toxicity of ca rbofuran (per EPA’s Worker Protection Standard).

Most crops with postapplication activities failed to reach MO Es of 100 within the currently prescribed REIs. Only sunflowe r and sorghum had postapplication MOEs of 100 within the label REI of 14 days.

16Table 7. Crop Groupings, Selected Transfer Coefficients, Treated Crops, Rates, Proposed REIs, Current REIs

Transfer Coefficient (cm2/hr) # of days until MOE

reaches 100 Transfer

Coefficient

Group Crop Max
Foliar

Rate (lb ai/acre) DFR
Data Used Low Med High Low Med High

Soybeans 0.25 Cotton 100 1500 6 12

Small Grains 0.25 Cotton 100 1500 6 12

Alfalfa 1 Potatoes 100 1500 4 >14* Field/row

crops, Low/medium Sugar Beets 2 Potatoes 100 1500 8 >14* Corn (MN site) 100 1000 7 10 Corn (field and pop) 1 Corn (CA site) 100 1000 25 >32*

Corn (MN site) 100 1000 17000 2 10 >11* Corn (sweet) 0.5 Corn (CA site) 100 1000 17000 18 32 >32*

Sunflowers 0.5 Potatoes 100 1000 0 13 Field/row

crops, Tall

Sorghum 0.5 Potatoes 100 1000 0 13 Sugarcane Sugarcane 0.75 Potatoes 100 1000 2000 2 >14* Vegetable, root Potatoes 1 Potatoes 300 1500 4 >14* * Studies ended at the number of days i ndicated, and MOEs still had not reached 100.

Drench applications made to container grown nursery stock may result in dermal exposure to workers performing postapplicati on reentry tasks and for workers handling treated soil while moving containers. Howe ver, the Agency has no exposure data to estimate these exposures.

6. Smoker Assessment

A short-term inhalation risk assessme nt for adult smokers has been completed, since carbofuran is registered for use on tobacco. Based on the short-term inhalation BMDL10 of 0.01 mg/kg/day (based on red blood cell ChE inhibition in adult male rats),

the short-term MOE for carbof uran exposure from the use of tobacco is 12. This

conservative risk estimate is above HED’s le vel of concern for inhalation exposure to

carbofuran.

7. Human Incident Data

For a review of the pesticide poisoni ng incident data for carbofuran, EPA consulted the following data bases: (1) O PP Incident Data System (IDS); (2) Poison Control Centers (PCC); (3) California Departme nt of Pesticide Regulation; (4) National Pesticide Telecommunications Network (N PTN), and (5) National Institute of Occupational Safety and Health’s Sentinel Even Notification System for Occupational Risks (NIOSH SENSOR). In all, more th an 700 possible carbofur an poisoning incidents were reported.

In the IDS, from 1996 through 2003, there have been 42 reported incidents from carbofuran exposure. Common among these reports is evidence th at carbofuran is a

17prevalent cause of eye problems, which was report ed in about one quarter of all the cases. Although data were often limited, most cases invo lved failure to wear proper protective equipment, or they occurred when workers were cleaning or repairing spray equipment.

PCC results for the years 1993 through 2001 for occupational and nonoccupational incidents involving adults and older children and for children under age six were compared between carbofuran and all other reported pesticides. The PCC data indicate that carbofuran exposur e is likely to result in more serious medical outcomes and serious medical care than expos ure to other pesticides. Mo st of the reported symptoms for carbofuran incidents were specific to c holinergic poisoning and most resulted from dermal and inhalation exposure, rather than oral exposure. While approximately four percent of the non-occupational incidents could be attributed to misuse, or misreading of the label, it was not possible to determine what percentage of occupational incidents were

attributable to misuse.

On the list of the top 200 chemicals for which NPTN received calls from 1984 to 1991 inclusively, carbofuran was ranked 37 th , with 103 incidents in humans reported.

In the NIOSH/SENSOR data (surveillan ce in seven states) there were 19 reports due to carbofuran alone, out of 4,221 reports.

A 1997 EPA incident review stated that , overall, carbofuran was judged second among 28 pesticides on measures of hazard deri ved from California and PCC data. Most of the risk from this pesticide is due to use by pesticide handlers, especially mixer/loaders

who handle the concentrated material. Less often, groups of people have been poisoned from spray drift of from exposure to field residue. A 1998 case in California illustrates

the effects from field residues when workers reentered treated cotton fields within two hours, instead of the required 48 hours, after application. Such residues are capable of causing moderate to relatively serious e ffects which require medical treatment.

Detailed descriptions of incidents repo rted to the California Pesticide Illness Surveillance Program from 1982 through 2002 id entified a total of 88 cases in which

carbofuran was either used alone or in combination with othe r chemicals, but was judged to be responsible for the reported health eff ects. The majority of illnesses were of a systemic type. The majority of incidents occur among handlers who mix, load, and apply carbofuran in agricultural fields.

The number and rate of poisoning cases due to carbofuran exposure is sufficient to warrant priority attention to risk reduction measures for this pesticide.

B. Environmental Risk Assessment

The ecological risk assessment for car bofuran primarily focused on the liquid (flowable) formulation because it makes up the greatest portion ( ≥ 99%) of carbofuran’s uses. However, since some granular product uses remain, a summary of the associated

18ecological risk of these uses is presented se parately in the ecologi cal risk assessment (see section 4.0 of Appendix 1 of th e ecological risk assessment).

Terrestrial and aquatic plants were not a pa rt of this risk assessment. Since the

mode of action of carbofuran is cholinestera se inhibition and both te rrestrial and aquatic plant studies show no phytotoxic effects, the Ag ency does not have concerns for plants as

a result of use of carbofuran.

Three lines of evidence were examined to ev aluate the risk of the use of flowable carbofuran products to non-targ et animal species. They in clude a screening level risk assessment (deterministic), a refined assessmen t (probabilistic) for a quatic risks and acute risks to birds, and the considera tion of field data for carbofuran.

First, standard screening level quotient m odels were used for estimating the acute and chronic risk to non-target aquatic and terrestrial organisms associated with the major

uses of flowable carbofuran. This screeni ng level ecological risk assessment compared toxicity endpoints from eco logical toxicity studies to estimated environmental concentrations (EECs) based on environmental fate characteristics and pesticide use data. To evaluate the potential risk to non-tar get organisms from the use of carbofuran products, the Agency calculated risk quotients (RQ), which are the ratio of the EEC to the most sensitive toxicity endpoint values, su ch as the median lethal dose (LD50) for terrestrial organisms or the median lethal concentration (LC 50 ) for aquatic organisms. These RQ values are then compared to the Ag ency’s levels of concern (LOCs), given in Table 8, which indicate whether a pesticide, wh en used as directed, has the potential to cause adverse effects on non-target organism s. When the RQ exceeds the LOC for a particular category, (e.g., endange red species), the Agency presumes a risk of concern to that category. These risks of concern may be addressed by further refinements of the risk assessment or mitigation. Use, toxicity, fate, and exposure are considered when characterizing the risk, as well as the relative degree of uncertainty in the assessment.

Table 8. EPA’s Levels of Concern and Associated Risk Presumptions

Risk Presumption LOC

terrestrial

animals LOC aquatic animals

Acute Risk - there is potential for acute risk 0.5 0.5

Acute Endangered Species - endangered species may be adversely affected 0.1 0.05

Chronic Risk - there is potential for chronic risk 1 1

Secondly, to help understand the ecological risk estimates derived from the screening level (deterministic) assessment, probabilistic methods were employed to provide more refined risk estimates that m ove away from the prot ective assumptions of the quotient model by using less conservati ve exposure scenarios and biological information on wildlife species likely to be asso ciated with carbofuran use. The refined probabilistic assessment models estimate the magnitude and probability of acute effects

19to non-target species occurring from pesticides by integrating distributions of carbofuran exposure with distributions of toxicity. The refined risk assessment addresses bird mortality (acute), as well as survival and re productive (chronic) effect s to fish and aquatic invertebrates following applica tion of carbofuran. The probabi listic models and methods were subjected to external peer review by the FIFRA Science Advisory Panel.

Lastly, available field data , including field studies, monitoring programs, and well-documented wildlife kill incident reports at tributed to the normal agricultural use of

flowable carbofuran were examined.

All three lines of evidence s upport the conclusion that th ere are risk concerns to both aquatic and terrestrial species from acute and chronic exposure following the use of

flowable carbofuran: risk concerns ar e particularly high for avian species.

For a more detailed explanation of the ecological risks posed by the use of carbofuran, refer to “Revised Ecological Carbofuran RED Chapter,” dated March 8,

2006.

1. Environmental Fate and Transport

Carbofuran is highly mobile in soils a nd can therefore leach into groundwater and

enter surface water as runoff. Carbofuran breaks down into several degradates though hydrolysis, photodegradation and moderate bacter ial degradation at rates that depend on environmental conditions. Hydrolysis is faster in water with a pH ≥ 7 (basic conditions), with a half-life ranging from a few hours to 28 da ys. Carbofuran is stable to hydrolysis in acidic water. Photodegradation is fast in a thin water layer, w ith a half-life of 6 days. In the top few millimeters of a sandy loam soil, carbofuran degrades in 78 days. There is low potential for bi oconcentration of carbofuran a nd its metabolites/degradates.

2. Ecological Risk Estimation

a. Terrestrial Organisms

In its screening level (deterministic) a ssessment, the Agency assessed exposure to terrestrial organisms by first predicting the amount of carbofuran residues found on animal food items and then using informa tion on typical food consumption by various species of birds and mammals to determine the amount of pesticide consumed. The

amount of residues on animal feed items is based on the Fletcher nomogram and the current maximum and minimum application ra tes, maximum numbers of applications, and potential for residue dissipation between a pplications. The Fletcher nomogram is a model developed by Hoerger and Kenaga (1972) and modified by Fletcher (1994).

i) Birds

Carbofuran is characterized as “very highly toxic” to bi rds on an acute oral basis and “highly toxic” on a sub-acute basis. Chronic toxicity testing in birds showed dose20related parental mortality at all test c oncentrations, so a NOAEL and LOAEL could not be established. A LOAEL of <2.0 mg/kg-diet was chosen as the toxicological risk assessment for chronic risk assessment, sinc e 2.0 mg/kg-diet was the lowest dose tested.

Table 9. Summary of Avian Toxicity Data Used for Risk Assessment

Test Type Species (Citation) Endpoint Toxicity Category Affected Endpoints

Avian acute effects (oral) Fulvous whistling duck ( Dendrocygna bicolor ) (Hudson et al ., 1984) LD 50 = 0.238 mg/kg Very highly

toxic NA

Avian chronic effects (reproduction) Mallard duck ( Anal platyrhynchos ) (Roberts et al ./1982b) NOAEC:

not
determined

LOAEC = 2

ppm NA Dose-related parental mortality at all

test
concentrations

Acute RQs exceed the LOC for all uses of flowable and granular carbofuran. Table 10 presents the RQs for flowable carbof uran as they relate to the minimum and maximum use rates on various crops. The lowe r end of the range re presents RQ values associated with large birds whose body weight is equivalent to 1,000 g, while the higher end of the RQ range is associated with sma ll birds of 20 g. For RQs calculated for use of granular carbofuran, see the Granul ar Carbofuran Risk Assessment.

Table 10. Avian (Herbivore ) Acute RQs fo r Flowable Carbofuran Based on Filvous Whistling Duck LD 50 of 0.238 mg/kg (Level of Concern = 0.5)
RQ Values at Minimum Application Rates RQ Values at Maximum Application Rates Crop Large Birds Small Birds Large Birds Small Birds

Alfalfa 17 144 134 1,150 Corn (all) 67 575 804 6,898

Cotton 28 241 63 538 Grapes 201 1,724 268 2,299

Potatoes 67 575 157 1,345 Small grains (wheat, oats, barley) 17 144 63 538 Sorghum 20 5,633 27 6,553 Soybeans 17 144 63 538 Sugarcane 67 575 188 1,613

Sunflowers 17 241 125 1,075

Tobacco 80 69 0 121 1,035

The chronic risk LOC is also exceeded for all avian species in all application scenarios. All scenarios compared four differe nt feeding groups: short grass, tall grass, broadleaf plants/insects and s eeds. The lower RQ values are associated with granivores (seedeaters) and the higher values are associated with herbivores (short grass eaters). The NOAEC was <2.0 mg/kg; the Lowest Observed Adverse Effect Concentration (LOAEC) was 2.0 mg/kg; and at all other concentr ations tested, the test birds died.

21Table 11. Avian Chronic RQs for Flowable Carbofuran Based on a Mallard NOAEC of <2.0 mg/kg (Level of Concern = 1.0)
RQ Values at Minimum Application Rates RQ Values at Maximum Application Rates Crop Granivores (Seed) Herbivores (Short Grass) Granivores (Seed) Herbivores (Short Grass)

Alfalfa 1 15 8 120

Corn (all) 4 90 2 720

Cotton 1 30 2 56 Grapes 15 135 11 473

Potatoes 4 60 4 224 Small grains (wheat, oats, barley) 1 15 4 56 Sorghum 1 30 7 690 Soybeans 1 15 4 56 Sugarcane 4 60 11 168

Sunflowers 1 50 2 112

Tobacco 5 72 5 108

The refined probabilistic assessment (s econd line of evidence), which assessed

acute avian risk associated with use on corn and alfalfa only, predic ted high mortality in at least some species, regardless of the a pplication rate and met hod. The analysis took into consideration both foliar and soil applicatio ns at use rates that span the majority of application rates for which carbofuran is regist ered (0.125 to 1.0 lbs a.i./A). Based on the sensitivity distribution, the more sensitive th e species, the higher th e mortality predicted from exposure. It is possibl e that crops with a higher appl ication rate of carbofuran would result in greater avian morality. Results of the refined assessment show that from 55 to 95% of the bird species modeled will expe rience at least some mortality as a result of the application of flowable carbofuran. At the highest applica tion rate, if exposed, 62% of bird species will experience 10 % mort ality on average, and 23% of bird species will have 70% mortality or greater, with a predicted maximum mortality rate of 93%.

ii) Mammals

Carbofuran is considered to be highly toxic to mammals on an acute basis. Chronic toxicity testing on la boratory rats showed reduced offspring survival and body weight reductions.

Table 12. Summary of Mammalian Toxicity Data for Terrestrial Animals Exposed to

Dimethoate

Test Type Species (Citation) Endpoint Toxicity Category Affected Endpoints

Mammalian acute effects (oral) Laboratory mouse ( Mus

musculus ) (Fahmy et al . 1970) LD 50 = 2.0 mg/kg (males) Very highly

toxic NA

Mammalian chronic effects (3-generation reproduction) Laboratory rat ( Rattus morvegicus ) (Goldenthal and Rapp/1979, MRIDs 00030514, 00030570, and 00079810) NOAEC = 20 ppm

LOAEL = 100 ppm NA Decreased pup

survival and

pup body weight decrease

22A refined assessment was not conducted for mammalian species. Few studies exist on wild mammalian species; therefore, the laboratory mouse LD 50 of 2.0 mg/kg/day was used to calculate RQs. The determin istic assessment showed that the acute and

chronic LOCs are exceeded for herbivorous , insectivorous, and granivorous mammals. RQs at the lower end of the range are asso ciated with 1,000 g mammals, while the high end of the range is associ ated with 15 g mammals.

Table 13. Acute RQs for all Mammal Groups LD 50 2.0 mg/kg/day

Herbivores and Insectivores Granivores Crop Large Mammal Small Mammal Large Mammal Small Mammal

Alfalfa 8 114 0.2 2

Corn 50 684 1 9

Potatoes 15 213 0.4 3 Sorghum 47 650 1 9

Cotton 4 53 0.1 1

LOC = 0.5

The chronic mammal LOC is exceeded for most uses. The lower RQ value is associated with seedeaters (granivores) and th e higher RQ is associated with short grass eaters (herbivores). This is usually the cas e because short grass contains the highest pesticide residues.

Table 14. Mammalian Chronic RQs for Applications LD 50 2.0 mg/kg/day

Herbivores and Insectivores Granivores Crop Large Mammal Small Mammal Large Mammal Small Mammal

Alfalfa 0.1 2 0.8 12

Corn 0.2 3 5 72

Cotton 0.2 3 0.3 6 Grapes 1 13 5 47

Potatoes 0.4 6 1 22 Sorghum 0.1 2 4 69

LOC = 1.0

iii) Non-target insects

Carbofuran is characterized as highly toxic to honey bees, based on a honey bee acute contact study (LD 50 = 0.16 μg/bee).

Terrestrial Field Data and Incidents

The field studies and incident data availa ble for flowable carbofuran (third line of evidence) support th e conclusions of the deterministic and probabilistic risk assessments; that is, acute risk from the use of flowable carbofuran to non-target terrestrial species is high.

The majority of controlled field stud ies conducted by the regi strant support the deterministic and probabilistic models. These studies demonstrated that bird mortality occurs at typical to low-end application rate s. Of the five studies submitted to the Agency, four had study designs that were adequate to meet the Agency guideline

23requirement for detecting significant mort ality events. In the acceptably designed studies, bird mortality in and around treated fields relative to untreated fields was great enough to reasonably conclude that carbofuran treatment-related mortality was the cause

of death.

From 1972 to 2000, 31 bird kill incidents ha ve been reported following the use of flowable carbofuran on five of the major crops where it is registere d, and these are almost exclusively bird kills as a resu lt of direct exposure. A majo rity (27) of the kills were reported following carbofuran use on corn and alfalfa, the two major crops where carbofuran is used. Thirty-seven species with a total of 7,300 carcasses were reported found in twelve different states, with both primary and secondary poisonings suspected.

In the late 1990s, the techni cal registrant made a number of label changes in order to reduce drinking water and ecological ri sks of concern. These included reducing application rates and numbers of applications for alfalfa, co tton, corn, potatoes, soybeans, sugarcane, and sunflowers. EPA therefore ev aluated incidents that have occurred since 1998. Since 1998, there have been 47 car bofuran incidents reported in EPA’s Ecological Incident Information System ( EIIS). Four of these incident s were from registered uses:

1) 1998 in PA, use on corn (flowable), 2 grackles 2) 1998 in PA, use on corn (flowable), 12 grackles 3) 2000 in NM, use on alfalfa (flowable), 800-1200 snow geese and ducks, and 4) 2000 in CA, use on alfalfa (flowable), 4 bee hives.

The remaining incidents were from intentiona l misuse (28) or the legality of use was undetermined (14). Of the 47 incidents, 13 we re attributed to fl owable carbofuran, two were attributed to granular carbofuran, and for the remaining incidents (32) the formulation was not reported.

Additionally, three incide nts since 2000 (two in 2000 and one in 2004) were reported aggregately by the registrant, and are not in the EIIS. Deta ils are not available

on these incidents.

b. Aquatic Organisms

For exposure to aquatic fish and inverteb rates, EPA considers surface water only, since most aquatic organisms are not found in groundwater. Surface water models are used to estimate exposure to freshwater a quatic animals, since monitoring data are generally not from studies targeted on sm all water bodies and primary streams within agroecosystems where the pesticide is used and where many aquatic animals are found. The modeling results used in risk calculations for carbofuran are detailed in “Revised Ecological Carbofuran RED Ch apter,” dated March 8, 2006.

Carbofuran concentrations in surface water bodies were estimated using PRZM and EXAMS and several crop/location scenarios and application rates which were chosen to ensure that: (1) the greatest acreage treate d with flowable carbofuran was assessed; (2)

24application rates covered all label use rates; and (3) PRZM/EXAMS scenario site vulnerability was at the high-end for the crop and carbofuran use combination. These crop scenarios are outlined in Table 15 below.

Table 15. Estimated Environmental Concentrations ( μ g ai/L)* of Carbofuran in Surface

Water for Selected Use Patterns
Using Minimum Rate Using Maximum Rate Crop/Location Acute 21-day Avg 60-day Avg Acute 21-day Avg 60-day Avg

Alfalfa, California 0.7 0.6 0.4 5.2 4.5 3.0 Alfalfa, Pennsylvania 0.7 0.6 0.4 5.7 4.6 3.0 Corn, Illinois 17 14 9.4 25 20 17 Cotton, Mississippi 10 7.9 5.5 11 8.2 5.7 Grape, California 0.31 0.24 0.15 7.0 5.4 3.5 Potato, Maine 3.6 2.9 2.0 26 21 14 Potato, Idaho 4.5 3.4 2.2 6.7 5.1 3.3 Sorghum, Texas 36 27 18 36 27 19 Tobacco, North Carolin a -- -- -- 10 7.7 5.0 * EEC values represent the 1-in-10 year maximum concentration for the designated time interval.

i) Freshwater and Estuarine/Marine Fish

Carbofuran is very highly toxic to fr eshwater and estuarine/marine fish on an acute basis. Chronic toxicity testing with fres hwater fish revealed larval survival as the most sensitive endpoint (NOAEC = 24.8 ppb a.i., LOAEC = 56.7 ppb a.i.). The

available chronic test showed estuarine/marine fish were more sensitive than fresh water fish with embryo hatching as the most sensitive endpoint (NOAEC = 2.6 ppb a.i., LOAEC = 6.0 ppb a.i.). Table 16 summarizes the data that s upport the toxicity endpoints used in assessing the risks to fish.

Table 16. Summary of Measurement Endpoint Values Used to Calculate Screening Level RQs for Fish

Assessment Endpoint Test Species (Citation) Endpoint Toxicity Category Affected Endpoints

Freshwater fish acute

effects Bluegill sunfish ( Lepomis

macrochirus ) (MRID 400980-01) LC 50 = 88 Very highly

toxic NA

Freshwater fish chronic

effects Rainbow trout ( Oncorhynchus mykiss )

(Acc. GEOCAR08) NOAEC = 5.7 ppb a.i. NC a Larval survival,

scoliosis

Estuarine/marine fish

acute effects Atlantic silverside ( Menidia

menidia ) (Acc. 260899) LC 50 = 33 Very highly

toxic NA

Estuarine/marine fish

chronic effects Sheepshead minnow ( Cyprindodon varigatus ) (MRID 432505-01) NOAEC = 2.6 ppb a.i. NC a Embryo hatching

a Not characterized

According to the deterministic assessment , carbofuran is not expected to reach surface water concentrations high enough to exceed the acute risk LOC for any crop

25application for freshwater fish. The chroni c risk LOC is exceeded; however, for use on corn, sorghum, and potatoes. For estuarine/ marine fish, there were acute and chronic LOC exceedences resulting from all uses.

Table 17. Acute and Chronic RQ Range s for Fish at Maximum and Minimum Application Rates

Freshwater Estuarine/Marine Crop Acute Chronic Acute Chronic

Alfalfa 0.01-0.06 0.07-0.53 0.02-0.17 0.15-1.2

Corn 0.19-0.28 1.6-3.0 0.52-0.76 3.6-6.5

Cotton 0.11-0.13 0.96-1.0 0.3-0.33 2.1-2.2 Grapes 0.01-0.08 0.03-0.61 0.01-2.1 0.06-1.3

Potatoes 0.04-0.3 0.35-2.5 0.11-0.79 0.77-5.4 Sorghum 0.41 3.2-3.3 1.1 6.9-7.3

Tobacco 0.11 0.88 0.3 1.9

Results of the refined probabilistic assessm ent show that for all uses of carbofuran modeled for surface water, at least 95% of exposed freshwater fish species will experience less than 0.5% mortality for any give n use. Reproductive effect levels for the most sensitive freshwater species, bluegill sunfish, are exceeded in at least 4% (approximately 1 out of 25 year s) of application years for all crops and up to 89% of application years (approximately 9 out of 10 years) for use on corn.

For exposed Atlantic silverside fish (estuarine), use on corn and sorghum is estimated in modeled surface waters to, on averag e, result in greater than 18% mortality. However, for the other crop uses modele d, the results indicated no demonstrable mortality (<1 case of mortality in a million) for the minimum application rate on cotton to 9% mortality for the maximum application to potatoes.

ii) Freshwater and Estuarine/Marine Invertebrates

Carbofuran is considered to be very highly toxic to freshwater and

estuarine/marine invertebrates on an acute basis. Table 18 summa rizes the data that support the toxicity endpoint s used in assessing the risks to invertebrates.

Table 18. Summary of Measurement Endpoint Values Used to Calculate Screening Level RQs for Aquatic Invertebrates

Study Type Test Species (Citation) Endpoint Toxicity Category Affected Endpoints

Freshwater invertebrate

acute effects Water flea (Ceriodaphnia dubia) (Bailey et al., 1996) EC 50 = 2.23 Very highly

toxic Mortality

Freshwater invertebrate

chronic effects ( Daphnia magna and Ceriodaphnia dubia ) (Acc. 262093, GEOCAR10) ENEC

0.75 Not
classified Reproduction

26Study Type Test Species (Citation) Endpoint Toxicity Category Affected Endpoints

Estuarine/marine

invertebrate acute effects Pink shrimp ( Penaeus duorarum ) (MRID 40228401) LC 50 = 4.6 Very highly

toxic Mortality

Estuarine/marine

invertebrate chronic

effects Mysid shrimp ( Americanysis bahia ) (MRID 40536001) NOAEC =

0.4 Not
classified Reproduction

ENEC = Estimated No Effect Concentration

According to the deterministic assessme nt, carbofuran is not expected to reach surface water concentrations high enough to ex ceed the acute risk LOC or chronic risk

LOC for freshwater invertebrates at minimum la bel rates for alfalfa and grapes. All other

uses exceed the acute and chronic risk LOCs . For estuarine/marine invertebrates, the acute LOC was exceeded for saltwater fish for corn, potatoes, and sorghum uses, with the chronic LOC exceeded for all uses except at minimum application rates to alfalfa and

grapes.

Table 19. Acute and Chronic RQ Ranges fo r Invertebrates at Maximum and Minimum Application Rates

Freshwater Estuarine/Marine Crop Acute Chronic Acute Chronic

Alfalfa 0.31-2.6 0.8-6.1 0.15-1.2 1.5-12

Corn 7.6-11 19-27 3.7-5.4 35-50

Cotton 4.5-4.9 11 2.2-2.4 20-21 Grapes 0.14-3.1 0.32-7.2 0.07-1.5 0.6-14

Potatoes 1.6-12 3.9-28 0.78-5.7 7.2-53 Sorghum 16 36 7.8 68

Tobacco 4.5 11 2.2 19

In the refined probabilistic assessment, for modeled surface water, on average at least 5% of exposed freshwater invertebrate species were estimated to experience greater than 80% mortality and 25% of exposed freshwat er species were estimated to have up to 28% mortality for most uses of carbofuran, except for the Idaho and Washington Special Local Need (SLN) labeled rate on potato es. Reproductive effect levels for C. dubia , the

most sensitive freshwater invertebrate teste d, were exceeded for nearly all uses, except cotton and the Idaho and Washington SLN labe led rate for potatoes, in all application years. The frequency of exceedences of the reproductive level was in the range of 70%

for cotton and 43% for the Idaho a nd Washington SLN labeled rates.

For exposed pink shrimp, results of the refined assessment show essentially 100% mortality in modeled surface waters for use on corn and sorghum and greater than 83% mortality for use on potatoes. For the othe r application rates, methods and crops, the median percent mortality estimate for expos ed pink shrimp populations ranges from 0.6% for the minimum application rate for cotton to 69% for the maximum application rate on

grapes.

27Aquatic Field Data and Incidents In comparison to birds, relatively few incidents with fish and shellfish have been reported, and only limited monitoring has been conducted in associati on with the use of liquid carbofuran in aquatic habitats. In Calif ornia, elevated levels of carbofuran in the Colusa Basin resulted in the listing of that area for Total Maximum Daily Load (TMDL) development. Eight incidents have been at tributed to carbofuran use according to the

label directions. Two of these incidents we re associated with flowable carbofuran formulations, two with granular, and for the re mainder, the formulation was not reported. More than 600 fish were killed in two ponds following use of liquid carbofuran spray on alfalfa in Clark County, Missouri, following a rain event in May 1981. Another incident, involving liquid carbofuran chemigation to grapes, occurred in San Joaquin County, California. In that incident (November 1991), more than 3,000 fish, 4,000 crayfish and frogs, and 5,000 other large aquatic invertebrates were killed in a creek near a vineyard.

3. Risk Characterization

The Agency has taken action in the pa st for avian risks from the granular formulation of carbofuran. To arrive at the current decision, the Agency used multiple lines of evidence, including refined probabilistic risk estimates, to conclude that the flowable formulation of carbofuran also poses significant acute risks to birds. In addition, based on the previously conducted ri sk assessments, and extrapolating from the assessments on the flowable formulation, EPA continues to believe that the granular formulation poses significan t acute risks to birds.

The terrestrial risk assessments also s how acute and chronic risks to mammals and chronic risks to birds. The aquatic assessmen ts show some risks to fish and significant risks to aquatic invertebrates. There is lo wer confidence in the estuarine/marine aquatic

risk conclusions relative to the ot her non-target organism assessments.

Carbofuran has often been misused to poi son predators, including foxes, coyotes, wolves, and bears. The technical registra nt has conducted an educational/stewardship program to deter misuse, but intentional baiting continues to be a concern with

carbofuran.

Many carbofuran incidents which have been classified as “misuse” or “off-label” appear to be the result of mi stakes in application, rather than deliberate misuse. Given the high toxicity of carbofuran, the margin of error is small so that a minor mistake can have serious consequences.

There is high confidence in these risk assessment findings since the deterministic and probabilistic risk assessments, as well as controlled field studies and incident reviews, all support the same conclusion: that carbofuran use poses potentially serious risks to non-target organisms.

284. Endangered Species Considerations

The Agency’s preliminary risk assessment for endangered speci es indicates that RQs exceed the endangered species LOC for te rrestrial and aquatic animals, indicating the potential for direct effects. Further, poten tial indirect effects to any species dependent upon a species that experiences effects from us e of carbofuran can not be precluded based on the screening level ecological risk asse ssment. These findings are based solely on EPA’s screening level assessment and, because they do not take into account such factors as whether the species would be expected to be exposed to carbofur an, do not constitute “may affect” findings under the Endangered Species Act.

EPA is currently engaging in informal consultations with the Fish and Wildlife

Service and the National Marine Fisheries Se rvice, which is a part of the National Oceanic and Atmospheric Administration. Th is means that the Agencies are working together to conduct a full endangered species assessment for carbofuran, which is separate from this IRED. The likelihood of potential impacts to endangered species will

need to be assessed for all counties in which: 1) crops registered for carbofuran use are grown; and 2) contain habitat fo r at least one listed species.

IV. Interim Risk Management, Reregis tration, and Tolerance Reassessment

Decision

A. Determination of Reregistration Eligibility

Section 4(g)(2)(A) of FIFRA calls for th e Agency to determine, after submission of relevant data concerning an active ingred ient, whether or not products containing the active ingredient are eligible for reregistrati on. The Agency has previously identified and required the submission of the generic (tec hnical or manufacturi ng-use grade) data required to support reregistration of products containing carbofuran as an active ingredient.

The Agency has completed its review of submitted data and its assessment of the ecological, occupational, and dietary risks asso ciated with the use of pesticide products containing the active ingredient carbofura n. Based on these data, the Agency has

sufficient information on the human health a nd ecological effects of carbofuran to make its interim decisions as part of the tole rance reassessment process under FFDCA, as amended by FQPA, and the reregistration pr ocess under FIFRA, pending completion of the cumulative assessment of the N-methyl carbamate class of pe sticides, of which carbofuran is a member. Additional mitigati on may be necessary after this cumulative assessment is completed.

The Agency has determined that all products containing carbofuran are not eligible for reregistration. Some uses have been identified as providing moderate benefits to growers, and those will be subject to a phase-out.

29B. Public Comments and Responses

Through the Agency’s public participation process, EPA worked extensively with stakeholders and the public to reach the re gulatory decisions for carbofuran. During the most recent public comment period on the risk assessments, which closed on May 22, 2006, the Agency received many sets of commen ts from stakeholders. These included comments from the technical registrant, grow ers, the Fish and Wildlife Service, the National Agricultural Aviation Association, the Natural Resource Defense Council, and others. The comments included some urging the Agency to regulate carbofuran more stringently, as well as some requesting that the Agency retain certain uses. These comments, in their entirety, are available in the public docket (docket # OPP-2005-0162)

at http://www.regulations.gov. EPA has prepared responses to these comments and they are posted in the docket, along with this IR ED. The Agency also received comments after the comment period closed, including 23 additional grower comments in support of

carbofuran and several thousand comments fr om private citizens requesting that the Agency cancel use of carbofuran.

In addition, EPA worked with USDA to solicit input from th e grower community on the importance of carbofuran use for thos e crops with < 1% of cropped area treated with carbofuran. EPA received many comments from growers through this process. EPA has considered these comments, and will be responding to them through a formal response to comments memo, which will be pla ced in the public docket, along with this

document.

The IRED and technical supporting docume nts for carbofuran are also available to the public through EPA’s el ectronic public docket and comment system, the Federal Docket Management System (FDMS), under [legacy] docket identi fication (ID) number EPA-HQ-OPP-2005-0162. In addition, the carbof uran IRED may be downloaded or viewed through the Agency’s website at http://www.epa.gov/pesticides/reregistration/status.htm

.

C. Regulatory Position Under FIFRA and FFDCA

The following is a summary of the rationale for managing risks associated with the use of carbofuran. Under FIFRA, the Ag ency is proposing to cancel all uses of carbofuran, due to ecological and occupational risks of c oncern (See the ecological and human health risk assessments for carbofuran). In addition, there are dietary risks of concern from some crops. See the first list ing of crops under Mitiga tion Summary below.

Benefits are low to moderate for all of these uses, and do not outweigh the risks.

There are several uses for which residue s do not pose dietary risks of concern and which have moderate benefits to growers [art ichokes, chile peppers in the Southwestern U.S., cucurbits (granular form ulation only), spinach grown fo r seed, sunflowers, and pine seedlings in the Southeastern U.S.]. For th ese uses, EPA is allowing a 4-year phase-out

in order to allow time for new alternatives to become available to growers. In addition, import tolerances will be maintained for bana nas, coffee, rice, and sugarcane. Dietary

30risks from the imported foods are below th e level of concern for these crops when considered together. For bananas, sugarcan e, and coffee, however , benefits to U.S. growers are low when compared to ecological and occupational risks from domestic uses of these crops. Carbofuran is no longer re gistered for use on rice in the U.S. Dietary risks of phase-out crops plus these importe d foods are below the Agency’s level of

concern.

1. Mitigation Summary

• Cancellation based on high ecological and worker risks and low economic benefits for growers

Sorghum Alfalfa Sweet corn Cotton Grapes Field corn and popcorn

Wheat Potatoes Bananas/plantains Cucurbits (flowable) Oats Soybeans Barley Tobacco Fallow/idle land Sugarcane Ornamentals Sugar beets Peppers (except chile)

• 4-year Phase-out for the crops wh ich have moderate benefits to

growers.

Artichokes, chile peppers in the Sout hwestern U.S., cucurbits (granular formulation only), sunflowers, spinach grown for seed, and pine seedlings

in the Southeastern U.S.

2. Regulatory Rationale

The Agency evaluated the relationship of risks and benefits for all carbofuran uses on a use-by-use basis. These analyses show high ecological and occupational risks for all carbofuran uses. In addition, as discussed belo w, the benefits associ ated with most crops are low, although some uses have moderate benefits. Based on the assessment of ecological and human health risks associated with carbofuran uses, the Agency has

determined that all uses of carbofuran do not meet the standard for continued registration

under FIFRA.

The Agency has identified a few niche uses, however, for which there are moderate benefits to growers. In the short te rm, at least, these moderate benefits would justify retaining uses for a limited time. Th e Agency believes that there are not enough affordable alternatives to provide effectiv e pest control for artichokes, chile peppers grown in the Southwestern U.S., cucurbits (g ranular formulation only), spinach grown for seed, pine seedlings grown in the Southeastern U.S., and sunflowers. EPA believes, however, that with the development of newe r chemistries and other alternative pest control practices, the benefits of these uses will decrease. Therefore, a phase-out period of four years, with some a dditional restrictions to ensu re the risks are reduced to

31acceptable levels, is appropriate, given the curre nt risk/benefit analyses. Cancellation of all but the phase-out crops reduces 98% of the total annual carbofuran use.

Additionally, some uses of carbofuran result in dietar y risks above the Agency’s

level of concern under FFDCA. Therefore, EPA has determ ined that, in addition to significant occupational and ecological risks, these uses would not be eligible for reregistration because the Agency cannot dete rmine that the tolerances for such crops meet the FQPA safety standard, based on the contribution of these uses to the aggregate

risks for carbofuran. The uses which do not fit within the dietary risk cup based on food residues alone from the individual commodity are: sweet corn, potatoes, and flowable carbofuran on the following cucurbits: pumpkins, squash (summer and winter), casaba melons, cucumbers, honeydew, and watermel on. Additionally, the dietary contribution of carbofuran in milk exceeds the Agency’s le vel of concern for infa nts and children with corn and alfalfa being cattle f eed items which are assumed to be the primary sources of

residues in milk. The risk estimates for cucurbits are based on both granular and

flowable carbofuran treatments at current us age levels. Estimated dietary risks based on the granular use only, with the current production cap of 2,500 pounds per year, are

below the level of concern.

The Agency also has dietary risk concer ns posed by exposure from drinking water sources. Since food alone completely fills th e risk cup (i.e. exposure is greater than 100% of the aPAD), any level of carbofuran residues in drinking water would result in additional risks of concern. Modeling estimates of residues in surface and ground water

from all uses result in residue values above EPA’s level of concern. In addition, recent USGS NAWQA monitoring data show multiple detections at low concentrations. The Agency recognizes that shallow, slightly acidic groundwater sources are the most

vulnerable to carbofuran contamination. Such groundwater sources are located primarily in portions of the Southeast and the east coas t of the United States. The uses for which EPA is not proposing immediate cancellation are those that are not expected to significantly contribute to gr oundwater contamination since they are limited in spatial extent of production (artichokes, chile peppers), applied in arid regions or in areas where pH is higher (chile peppers, sunflowers), or limited due to method of treatment (pine seedling dip). Cancellation of all other uses will reduce the amount of carbofuran applied from approximately 1 million pounds annua lly to approximately 19,500 pounds of use remaining for four years.

Additionally, because dietary risks from use of flowable carbofuran on cucurbits alone exceed the risk cup based on PDP food residue monitoring data and a high percent crop treated, the four year phase-out for cucu rbits applies only to granular carbofuran.

The Agency will maintain import tolerances for bananas, coffee, rice, and sugarcane. Dietary risks from the import to lerances are below the Agency’s level of concern when considered together with the food residues from the phase-out crops (56 % of the aPAD). There are currently domestic uses for bananas, suga rcane, and coffee, but they are ineligible for reregistration based on low benefits and ecological and occupational risks of concern.

323. Significance of Use

Carbofuran is a systemic insecticide whic h is used to control pests on a variety of fruit, vegetable, and field crops. Use has been declining in r ecent years and is now mostly limited to niche uses. Adequate altern atives exist for all cr ops except artichokes, chile peppers in the Southwestern U.S., cucurbits, spinach grown for seed, sunflowers, and pine seedlings in the Southeastern U. S. Use on cucurbits will be limited to the granular formulation based on dietary risks.

During the two public comment periods on the carbofuran risk assessments, the Agency received many grower comments in support of retaining carbofuran use for various crops.

EPA divided uses into two groups ba sed on percent crop treated. If a low percentage of a crop is treated, the Agency makes the preliminary assumption that the significance of use on that crop is also low. For these crops, the Agency consulted with the USDA Office of Pest Management Policy (OPMP) to determine whether there were niche uses which should be considered in any mitigation plan. The nineteen use sites in this category are: bananas, barley, co ffee, cotton, cranberry, flax, grapes, oats, ornamentals, pine forests, plantains, sor ghum, soybeans, spinach grown for seed, sugar beets, sugarcane, sunflowers, tobacco, a nd wheat. OPMP received comments from the Integrated Pest Management Centers on carbofur an use on these crops. In general, these comments supported the conclusion that mi nimal impacts would be expected if carbofuran were no longer available for thos e crops with less than one percent crop

treated.

For those use sites with either greater than 1% crop treated or at least 100,000 lbs carbofuran applied each year, the Agency a ssumed that the higher use frequency implied significance of use. For these sites, the Agency examined carbofuran use patterns, available alternatives, and the impacts of cancellation to growers. Analyses were conducted for artichokes, potatoes, field corn, alfalfa, cucurbits, and peppers. Through conducting these in-depth benefits analyses, the Agency was ab le to determine that, with the exception of artichokes, certain cucurbits, and chile peppers, minimal impacts would also be expected if carbofuran were no longer available for use on those crops with greater than 1% crop treate d or 100,000 lbs applied annuall y. The Agency’s benefits assessments will be posted to the carb ofuran docket, along with this IRED.

In addition, after the most recent pub lic comment period closed, the Agency received some new information from corn gr owers regarding the use of carbofuran as a rescue treatment for corn rootworm damage. The Agency therefore took particular care to examine potential benefits from this use. Corn rootworm pressure has been increasing for a variety of reasons, including rotation resistance (i.e., rootworms have become resistant to the control offered by rotati ng soybeans with corn ) and the uncertain performance of seed treatments under high rootworm pressure. In addition, increasingly higher production of corn and continuous co rn production are being practiced due to

33increasing demand for ethanol. When high root worm pressure is likely, most growers will use at-plant insecticides, such as tefluthr in, or plant genetically modified Bt corn. When low to moderate rootworm pressure is likely, growers will typically rely on seed treatments and survey for root damage instead of rootworm larvae. Clothianidin acts as a feeding depressant, and thus growers samp ling soil in corn fields for larvae may misinterpret the presence of moribund (inactive) larvae as a control failure. Extension entomologists have recommended that grower s look for root pruning and damage (rather than rootworm larvae) to assess the success of seed treatments. In limited circumstances, some growers may experience yield losses as a result of rootworm damage and have used

carbofuran as a rescue treatment over the corn canopy. However, based on information from a variety of state extension publica tions and experts and the general lack of supporting data, the Agency believes that resc ue treatments of carbofuran applied over the canopy to control corn rootworm damage perform erratically and are not a sound investment for growers.

There are several crops for which th e Agency believes there are moderate benefits to growers: artichokes, chile peppe rs in the Southwestern U.S., cucurbits, spinach grown for seed, sunflowers, and pine seedlings. Some mode rate benefits have also been identified for sweet corn for control of the wheat curl mite, which transmits High Plains disease. However, the Agency is not planning to allow a phase-out of this

use due to the fact that ther e are dietary risks of concern.

Flowable formulation

• Growers apply carbofuran to artichokes for control of cribrate weevils, proba bugs, and artichoke aphids. Effective alte rnatives exist for aphids; however, the

alternatives for cribrate weevil and proba bugs are not as effective (see

Alternatives Assessment for Carbofuran on Artichoke, D. Brassard and S. Smearman, July 14, 2006).

• Carbofuran is used on chile peppers fo r control of flea b eetles, thrips, and leafhoppers, as well as the green peach a phid in Arizona and Texas. There are adequate alternatives available; howev er, EPA acknowledges that some growers would face higher production costs without the availability of carbofuran. In addition, use of carbofuran on chile peppe rs is limited to Arizona, New Mexico, and Texas (see Impact Assessment for Carbofuran on Peppers, N. Zinn and E. Rim, June 28, 2006).

• Carbofuran is used on sunflowers to control stem weevils. Alternatives are available for the post plant foliar use, but not for the soil at-plant use. There are

also a number of natural enemies availabl e; however, it is unclear whether they can achieve adequate control of stem weevils (see Carbofuran Response to Comments and Alternatives Analysis for Crops with Low Usage, D. Brassard et al, July 7, 2006).

34• Only limited alternatives are available fo r control of pales a nd pitch weevil in pine seedlings (see Carbofuran Response to Comments and Alternatives Analysis for Crops with Low Usage, D. Brassard et al, July 7, 2006).

Granular formulation

The Agency and the technical registrant reached an agreement in 1991 that sales of granular carbofuran would be limited to 2,500 lbs a year. This agreement was based on the ecological risks of c oncern posed by use of carbofuran, and phase-out use is limited to cucurbits, spinach for seed, and pine seedlings only.

• Only limited alternatives are available fo r control of pales a nd pitch weevil in pine seedlings (see Carbofuran Response to Comments and Alternatives Analysis for Crops with Low Usage, D. Brassard et al, July 7, 2006).

• In spinach grown for seed, springtails and European craneflies can cause yield losses of 100%, and carbofuran is the only pesticide available for control of these pests (see Carbofuran Response to Comments and Alternatives Analysis for Crops with Low Usage, D. Brassard et al, July 7, 2006).

• There are adequate alternatives available for cucurbits; however, EPA acknowledges that some growers would face higher production costs without the availability of carbofuran. [see Impact Assessment for Carbofuran on Cucurbits (Cucumbers, Pumpkins, Squash, and Wate rmelon), N. Zinn and E. Rim, June 14, 2006.]

D. Endangered Species Considerations

Endangered species acute and chronic LOCs are exceeded for all groups of terrestrial animals (birds, mammals, and invert ebrates) for all uses and for all rates of flowable and granular formula tions of carbofuran, indicating a potential for direct effects on listed species. Endangered species acute and chronic LOC are also exceeded for all groups of aquatic organisms for most uses of flowable and the limited remaining granular

formulations of carbofuran. Exceedences of th e LOCs indicate a potential for effects to listed species.

The Agency has developed the Enda ngered Species Protection Program to identify pesticides whose use may cause a dverse impacts on endangered and threatened species, and to implement mitigation measures that address these impacts. The Endangered Species Act (ESA) requires federal ag encies to ensure that their actions are not likely to jeopardize listed sp ecies or adversely modify desi gnated critical habitat. To analyze the potential of registered pesticide uses that may affect any particular species, EPA uses basic toxicity and exposure data developed for the REDs/IREDs and considers

these data in relation to i ndividual species and their locations by ev aluating important ecological parameters, pesticide use info rmation, geographic relationship between specific pesticide uses and species locations, and biological requirements and behavioral

35aspects of the particular species, as part of a refined species-specific analysis.

Carbofuran is one of the first chemicals fo r which the Agency has begun a full, speciesspecific endangered species analysis. The Agency is currently participating in informal

consultations with the Fish and Wildlife Service and the National Marine Fisheries

Service within the National Oceanic and Atmospheric Administration. The Agencies hold monthly meetings to exchange information. This species-specific analysis is being completed separately from this IRED, and will take into consideration any regulatory changes recommended in this IRED that are being implemented at that time.

Following this future species-specific analysis, a determination that there is a likelihood of potential impact to a listed specie s or its critical hab itat may result in: limitations on the use of carbofuran, other measures to mitigate any potential impact, or

consultations with the Fish and Wildlife Service or the National Marine Fisheries Service as necessary. If the Agency determines use of carbofuran “may affect” listed species or their designated critical habitat, EPA w ill employ the provisions in the Services regulations (50 CFR Part 402). Until that species-specific anal ysis is completed, the risk mitigation measures being implemented through this IRED will reduce the likelihood that endangered and threatened species may be expos ed to carbofuran at levels of concern. EPA is not requiring specific carbofuran labe l language at the present time relative to threatened and endangered species. If, in the future, specific measur es are necessary for the protection of listed species , the Agency will implement them through the Endangered Species Protection Program.

E. Food Quality Protection Act Findings and Tolerance Summary

1. FQPA

a. Risk Cup Determination

As part of the FQPA tolerance reas sessment process, EPA assessed the risks associated with this N-methyl carbamate (NMC). The assessment is for this individual NMC, and does not attempt to fully reassess these tolerances as required under FQPA. FQPA requires the Agency to evaluate food to lerances on the basis of cumulative risk from substances sharing a common mechanism of toxicity, such as th e toxicity expressed by the NMCs through a common biochemical intera ction with the cholinesterase enzyme. The preliminary cumulative risk assessment for the NMC Cumulative Assessment Group, which includes carbofuran, was released in July 2005. The revised cumulative risk assessment is currently being developed and will be completed during 2006. The results of this NMC cumulative assessment, as well as the single chemical carbofuran assessment, will be considered in the final tolerance reassessment decision for

carbofuran.

EPA has determined that risk from food (dietary sources only) exposure to carbofuran exceeds its own “risk cup” (490% of the aPAD for children). Therefore,residues in drinking water will be of concern. Exposure from the crops allowed for fouryear phase-out plus the four crops maintained as import tolerances is estimated at 56% of

36the aPAD for infants, the popul ation subgroup with the highest exposure. Residues in water are expected to decline when use ceases.

b. Endocrine Disruptor Effects

EPA is required under the FFDCA, as ame nded by FQPA, to develop a screening program to determine whether certain substanc es (including all pes ticide active and other ingredients) “may have an eff ect in humans that is similar to an effect produced by a naturally occurring estrogen, or other endoc rine effects as the Administrator may designate.” Following recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), EPA de termined that there was a scientific basis for including, as part of the program, the androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC’s recommendation that EPA include evaluations of potential effects in wildlife. For pesticides, EPA will use FIFRA and, to the extent that effects in wildlife may help determine whether a substance may have an effect in humans, FFDCA author ity to require the wildlife evaluations. As the science develops and resources allow, screening of additional hormone systems may

be added to the Endocrine Disr uptor Screening Program (EDSP).

2. Interim Tolerance Summary

The Agency is proposing to cancel all us es of carbofuran based on ecological, occupational, and dietary risks of concer n, and to revoke all to lerances, with the exception of bananas, rice, sugarcane, and coff ee. These tolerances will be maintained for import purposes only. Several uses were identified as having m oderate benefits to growers, and the Agency is proposing to impl ement a 4-year phase-out for those crops. Therefore EPA is proposing to delay the effectiv e date of revocation of the tolerances for artichokes, corn, peppers, and sunflowers until 2010. All other tolerances will be proposed for revocation following completion of this IRED.

A summary of the dietary aggregate assessment for food and drinking water that supports the finding that the (1) time-limited rete ntion of the uses to be phased out and (2) retention of the import tolerances meets th e FQPA safety standard is presented in the Regulatory Rationale section of this document, and in the carbofuran reregistration docket (EPA-HQ-OPP-2005-0162).

37Table 20. Interim Tolerance Summary for Carbofuran

Commodity Current Tolerance,

ppm Tolerance Reassessment, ppm Comment/ [Correct Commodity Definition]

Tolerances Listed Und er 40 CFR §180.254 (a)

Alfalfa , fresh; alfalfa, hay; barley, grain; barley, straw; beet, sugar; beet, sugar, tops; corn, forage; corn, fresh (including sweet corn) (K+CWHR); corn, grain (including popcorn); corn, stover; cotton, undelinted seed; cranberry; grape; grape, raisin; milk; oat, grain; oat, straw; potato, raisins, waste; sorghum, fodder; sorghum, forage; sorghum, grain; soybean; soybean, forage; soybean, hay; strawberry; wheat, grain; wheat, straw 10 (5) Revoke

Banana 0.1 0.1 Maintained for import purposes.

Coffee bean 0.1 0.1 [Coffee, green bean] Maintained for import purposes.

Cucumber 0.4 (0.2)

Melons 0.4 (0.2)

Pumpkin 0.8 (0.6)

Squash 0.8 (0.6) Revoke

(Maintain at current level until expiration in 2010.) Revoke individual tolerances and establish a crop group tolerance for Cucurbit Vegetables Group 9.

Tolerance will expire in 2010.

Pepper 1 (0.2) Revoke

(Maintain at current level until expiration in 2010.) [pepper, nonbell]

Tolerance will expire in 2010.

Rice, grain 0.2 0.2 No Section 3 registrations. Maintained for import purposes.

Sugarcane, cane 0.1 0.2 Maintained for import purposes.

Sunflower, seed 1.0 (0.5) Revoke

(Maintain at current level until expiration in 2010.) Tolerance will expire in 2010.

Tolerances Listed Und er 40 CFR §180.254 (c)

Artichoke, globe 0.4 (0.2) Revoke

(Maintain at current level until expiration in 2010.) Tolerance will expire in 2010.

(Number in parentheses reflects the ppm level that residues of carbamates may not exceed.)

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