United States Prevention, Pesticides OPP-2005-0231
Environmental Protection And Toxic Substances July 27, 2006
Agency (7508P)
Reregistration Eligibility
Decision for
Metaldehyde
List A
Case No. 0576
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Reregistration Eligibility Decision (RED) Document
For
Metaldehyde
Approved by: fsf
Debra Edwards, Ph. D.
Director
Special Review and
Reregistration Division
Date: July 27, 2006
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TABLE OF CONTENTS
Metaldehyde Reregistration Eligibility Decision Team 5
Glossary of Terms and Abbreviations 6
I. Introduction 8
II. Chemical Overview 10
III. Summary of the Metaldehyde Science Assessments 11
A. Human Health Risk Assessment 12
1. Acute Toxicity 12
2. FQPA Safety Factor 12
3. Endpoint Selection 13
4. Dietary Exposure and Risk from Food and Drinking Water 15
a) Drinking Water Concentrations 15
b) Food + Water Exposures 15
c) Acute Dietary (Food and Drinking Water) Risk 15
d) Chronic Dietary (Food and Drinking Water) Risk 16
5. Residential Exposure and Risk 16
a) Residential Handlers 16
b) Residential Post-Application Exposure and Risk 17
6. Aggregate Exposure and Risk 18
a) Acute Aggregate Risk 18
b) Short-Term Aggregate Risk 18
c) Chronic Aggregate Risk 18
7. Cumulative Risk 19
8. Risk to Domestic Animals from Ingestion of Metaldehyde Granules in
Residential Settings 19
9. Occupational Risk Assessment 20
a) Handler exposures 20
b) Handler risks 21
c) Occupational post-application risks 21
B. Environmental Risk Assessment 21
1. Environmental Fate and Transport 21
2. Ecological Risk 21
a) Risk to Aquatic Organisms 22
(1) Toxicity to Fish and Aquatic Invertebrates 22
(2) Exposures of Aquatic Organisms to Metaldehyde 23
(3) Fish and Aquatic Invertebrate Risk Estimates 24
(4) Risks to Aquatic Plants 24
b) Terrestrial Risk 24
(1) Toxicity to Terrestrial Wildlife 24
(2) Other Terrestrial Wildlife 25
(3) Terrestrial Plants 25
(4) Potential Exposures for Terrestrial Wildlife 26
(5) Terrestrial Risk Estimates 27
c) Endangered Species 28
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C. Alternatives Assessment and Related Information 29
IV. Reregistration Decision 31
A. Risks of Concern and Risk Mitigation 31
1. Dietary 31
2. Residential 31
3. Aggregate 31
4. Occupational 31
5. General Concerns 32
6. Domestic Animals 32
7. Environmental 35
8. Other Measures Addressing Both Domestic Animal and Ecological Risks36
B. Tolerance Considerations 37
C. Eligibility Decision 38
V. What Registrants Need to Do 38
A. Submissions for Technical-Grade Active Ingredient Products 38
1. Within 90 Days of Receipt of the Generic DCI 38
2. Within Other Generic DCI Deadlines 38
B. Submissions for End-Use Products Containing Metaldehyde 39
1. Within 90 Days 39
2. Within Product DCI Deadlines 39
C. Manufacturing-Use ProductsData Requirements 40
D. Labeling 41
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Metaldehyde Reregistration Eligibility Decision Team
Office of Pesticide Programs:
Biological and Economic Analysis Division
Donald Atwood Biological Analysis Branch
Alan Halvorson Economic Analysis Branch
Environmental Fate and Effects Risk Assessment
Colleen Flaherty, Pamela Hurley, Environmental Risk Branch 3
Lucy Shanaman
Health Effects Risk Assessment
Jeff Dawson, Felecia Fort,
Matt Lloyd, Linda Taylor
Jerry Blondell
Registration Divsion
Shaj a Brothers
Dani Daniels, Venus Eagle
Dan Kenny
Risk Management
Jill Bloom, Dirk Helder
Office of General Counsel:
Robert Wing
U.S. Department of Agriculture:
Wilfred Burr
Reregistration Branch 1
Retired
Minor Use, Inerts & Emergency Response Branch
Insecticide/Rodenticide Branch
formerly of Insecticide/Rodenticide Branch
Reregistration Branch 2
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Glossary of Terms and Abbreviations
AGDCI
ai
aPAD
AR
BCF
CFR
cPAD
CSF
CSFII
DCI
DEEM
DFR
DWLOC
EC
EDWC
EEC
EPA
EUP
FDA
FIFRA
FFDCA
FQPA
FOB
G
GENEEC
GLN
HAFT
IR
LCso
LD50
LOC
LOD
LOAEL
MATC
mg/kg/day
Agricultural Data Call-In
Active Ingredient
Acute Population Adjusted Dose
Anticipated Residue
Bioconcentration Factor
Code of Federal Regulations
Chronic Population Adjusted Dose
Confidential Statement of Formula
USDA Continuing Surveys for Food Intake by Individuals
Data Call-In
Dietary Exposure Evaluation Model
Dislodgeable Foliar Residue
Drinking Water Level of Comparison.
Emulsifiable Concentrate Formulation
Estimated Drinking Water Concentration
Estimated Environmental Concentration
Environmental Protection Agency
End-Use Product
Food and Drug Administration
Federal Insecticide, Fungicide, and Rodenticide Act
Federal Food, Drug, and Cosmetic Act
Food Quality Protection Act
Functional Observation Battery
Granular Formulation
Tier I Surface Water Computer Model
Guideline Number
Highest Average Field Trial
Index Reservoir
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 expressed as the weight of substance per
weight or volume of water, air or feed, e.g., mg/1, mg/kg or ppm.
Median Lethal Dose. A statistically derived single dose that can be
expected to cause death in 50% of the test animals when
administered by the route indicated (oral, dermal, inhalation). It is
expressed as a weight of substance per unit weight of animal, e.g.,
mg/kg.
Level of Concern
Limit of Detection
Lowest Observed Adverse Effect Level
Maximum Acceptable Toxicant Concentration
Micrograms Per Gram
Micrograms Per Liter
Milligram Per Kilogram Per Day
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mg/L
MOE
MRID
MUP
NA
NAWQA
NPDES
NR
NOAEC
NOAEL
OP
OPP
OPPTS
PAD
PCA
PDF
PHED
PHI
ppb
PPE
ppm
PRZM/EXAMS
Qi*
RAC
RED
REI
RfD
RQ
SCI-GROW
SAP
SF
SLC
SLN
TGAI
TRR
USDA
USGS
UF
UV
WPS
Milligrams Per Liter
Margin of Exposure
Master Record Identification (number). EPA's system of recording
and tracking studies submitted.
Manufacturing-Use Product
Not Applicable
USGS National Water Quality Assessment
National Pollutant Discharge Elimination System
Not Required
No Observed Adverse Effect Concentration
No Observed Adverse Effect Level
Organopho sphate
EPA Office of Pesticide Programs
EPA Office of Prevention, Pesticides and Toxic Substances
Population Adjusted Dose
Percent Crop Area
USDA Pesticide Data Program
Pesticide Handler's Exposure Data
Preharvest Interval
Parts Per Billion
Personal Protective Equipment
Parts Per Million
Tier II Surface Water Computer Model
The Carcinogenic Potential of a Compound, Quantified by the
EPA's Cancer Risk Model
Raw Agriculture Commodity
Reregistration Eligibility Decision
Restricted Entry Interval
Reference Dose
Risk Quotient
Tier I Ground Water Computer Model
Science Advisory Panel
Safety Factor
Single Layer Clothing
Special Local Need (Registrations Under Section 24(c) of FIFRA)
Technical Grade Active Ingredient
Total Radioactive Residue
United States Department of Agriculture
United States Geological Survey
Uncertainty Factor
Ultraviolet
Worker Protection Standard
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I. Introduction
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended
in 1988 to accelerate the reregistration of products with active ingredients registered prior
to November 1, 1984. The amended Act calls for the development and submission of
data to support the reregistration of an active ingredient, as well as a review of all data
submitted to the Environmental Protection Agency. Reregistration involves a thorough
review of the scientific database underlying a pesticide's registration. The purpose of the
Agency's review is to reassess the potential risks arising from the currently registered
uses of metaldehyde, 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 FFDCA to require reassessment of all tolerances in effect on
the day before it was enacted. In reassessing these tolerances, the Agency must consider,
among other things, aggregate risks from non-occupational sources of pesticide exposure,
whether there is increased susceptibility among infants and children, and the cumulative
effects of pesticides that have a common mechanism of toxicity. When the Agency
determines that aggregate risks are not of concern and concludes that there is a reasonable
certainty of no harm from aggregate exposure, the tolerances are considered reassessed.
EPA decided that, for those chemicals that have tolerances and are undergoing
reregistration, tolerance reassessment will be accomplished through the reregistration
process.
Risks summarized in this document are those that result only from the use of
metaldehyde. The Food Quality Protection Act (FQPA) requires that, when considering
whether to establish, modify, or revoke a tolerance, the Agency consider "available
information" concerning the cumulative effects of a particular pesticide's residues and
"other substances that have a common mechanism of toxicity." Unlike other pesticides for
which EPA has followed a cumulative risk approach based on a common mechanism of
toxicity, EPA has not made a common mechanism of toxicity finding as to metaldehyde,
and metaldehyde does not appear to produce a toxic metabolite produced by other
substances. Therefore, for the purposes of reregistration, EPA has not assumed that
metaldehyde shares a common mechanism of toxicity with other compounds. For
information regarding EPA's efforts to determine which chemicals have a common
mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the
policy statements released by EPA's Office of Pesticide Programs concerning common
mechanism determinations and procedures for cumulating effects from substances found to
have a common mechanism of toxicity on EPA's website at
http ://www. epa. gov/pesticides/cumulative/.
Metaldehyde is a molluscicide used to control snails and slugs on a wide variety
of sites, including turf, ornamentals, berries, citrus, and vegetables. Data on the usage of
metaldehyde on nonagricultural sites are limited, but usage is likely less than 50,000
pounds of active ingredient per year (Ibs ai/year). About 11,000 Ibs ai/year is used on
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citrus and about 7,000 Ibs ai/year is used on artichokes. About 90% of metaldehyde is
used in the Pacific Northwest, California, and Hawaii.
Metaldehyde was first registered in 1967. The sole technical grade metaldehyde
registration in the U.S. is held by Lonza, Inc. Lonza maintains an agreement with end-
use product formulators that stipulates consistency in formulation and labeling. The end-
use product formulators are OrCal, Cony's, and Amvac, and there are additional sub-
registrants that do not independently formulate metaldehyde products, including The
Scotts Company LLC.
Metaldehyde products currently bear labeling for a large number of uses. The
Agency allowed registration of these uses at a time when a determination had been made
that metaldehyde was not taken up into plants and so tolerances were not needed. The
Agency has since determined that residues of metaldehyde are present in plants and that
tolerances are needed to account for residues in food and feed crops. Lonza is currently
supporting a subset of the uses on metaldehyde product labels through the development
of residue and other data; this subset comprises all the uses the Agency has evaluated for
reregistration. The uses evaluated by the Agency for reregistration are: turf, dichondra,
ornamentals, citrus, lettuce, cole crops and other leafy greens, tomato, strawberry, berries
(including blackberry, blueberry, currant, elderberry, gooseberry, and raspberries),
artichoke, and grass grown for seed.
This document presents EPA's decision regarding the reregistration eligibility of
the registered uses of metaldehyde. The Agency has conducted human health and
ecological risk assessments based on its review of the database supporting the uses of
metaldehyde. This document summarizes these risk assessments and describes the
mitigation measures needed to address risks identified during the reregistration process. As
a result of this review, the Agency has determined that the following uses of metaldehyde
are eligible for reregistration under FIFRA, provided that the risk mitigation measures
detailed in this document are adopted and the data requirements set forth in this document
are fulfilled: ornamentals, citrus, lettuce, cole crops and other leafy greens, tomato,
strawberry, berries (including blackberry, blueberry, currant, elderberry, gooseberry, and
raspberries), artichoke, and grass grown for seed. All other uses currently on metaldehyde
product labels are not eligible for reregistration and must be deleted from product labels.
The Agency has determined that a set of risk mitigation measures must be implemented,
via labeling or reformulation, to address the risks associated with the uses of metaldehdye
that are eligible for reregistration. These measures focus on risk reduction for domestic
animals and wildlife. In addition, the Agency is requiring that certain data be submitted in
support of the continued registration of metaldehyde. The Agency is releasing its
reregistration eligibility decision for metaldehyde with a 60-day public comment period to
solicit input on a number of mitigation measures. Once an Endangered Species assessment
is completed for metaldehyde, further changes to metaldehyde registrations may be
necessary, as explained in Section III of this document.
The Agency has also reassessed the lone existing tolerance for metaldehyde. The
current tolerance expression for metaldehyde residues is adequate. A tolerance of "zero"
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previously was established for residues of metaldehyde on strawberries [40 CFR
§180.523(a)]. Residue data submitted since that time are adequate to support a tolerance of
6.25 ppm for residues in/on strawberry. This metaldehyde tolerance is considered
reassessed.
The IR-4 program of the U.S. Department of Agriculture, which develops residue
data for minor and specialty crops, has done research on a number of additional new uses
for metaldehyde. At the current time, residue data for the use of metaldehyde on prickly
pear cactus and watercress are in development. While these uses were included in the
health effects and environmental risk assessments for metaldehyde, decisions on their
registration will not be made in this reregistration eligibility decision.
II. Chemical Overview
Chemical Structure:
Common Name:
Chemical Name:
CAS Registry Numbers:
PC Code:
Common Trade Names:
Basic Manufacturer:
Use Sites
Mode of Action:
Metaldehyde
2,4,6,8-tetramethyl-l,3,5,7-tetraoxacyclooctane
108-62-3
053001
Snail-N- Slug Beater, Bug-Geta Snail & Slug
Pellets, Slugit, Deadline, Slug & Snail Death,
Slug-Fest, Metarex
Lonza Inc.
Uses currently listed on product labels include turf,
ornamentals, citrus, cole crops, lettuce, tomato,
strawberry, blueberry, caneberries, artichokes, seed
crops, alfalfa, apples, asparagus, avocado, beans,
celery, cereal grains, clover, cherries, corn, dryland
taro, fallow land, garlic, ginseng, grapes, legumes,
lumberyards, mint, papaya, peaches, potato,
pumpkin, seed crops, and watermelon.
Active ingredient is ingested or absorbed; disrupting
mucous membranes and dehydrating snails & slugs
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Formulations:
Methods of Application:
granules, pellets, minipellets, meal, paste, viscous
liquid
Dry materials may be scattered or shaken directly
from the container; applied with a whirly-bird
spreader, fertilizer spreader, or tractor-drawn
spreader; or broadcast by air. Concentrates may be
diluted and applied via hose-on application or
sprinkler can. Liquids and pastes may be squeezed
directly from bottle.
Some labels do not provide clear use instructions.
Application rates on current labels may be as high
as 21 Ib/A, or 0.15 Ib ai/1000 square feet,
or 2 oz./lOO square feet.
Usage of metaldehyde on agricultural sites is summarized in Table 1. Sites in
boldface type are among those assessed for this RED.
Table 1. Screening Level Estimates of Agricultural Usage, as of April 2005
Use Rates:
Use Site
Seed Crops
Lemons
Artichokes
Oranges
Strawberries
Grapes
Watermelon
Avocado
Blackberries
Blueberries
Cauliflower
Celery
Peaches
Peppers
Raspberries
Sweet corn
Pounds active
ingredient
20,000
8,000
7,000
3,000
2,000
2,000
1,000
1,000
<500 each
Percent crop
treated
5
10
25
<1
5
<1
<1
<1
5
10
<1
<1
<1
<1
<1
<1
Maximum percent
crop treated
25
40
5
5
<2.5
<2.5
<2.5
<2.5
<2.5
<2.5
<2.5
<2.5
III. Summary of the Metaldehyde Science Assessments
The following is a summary of EPA's human health, domestic animal, and
ecological risk findings and conclusions for metaldehyde as presented in the risk
assessments and supporting documents developed by the Agency. The risk assessments
and related supporting documents are available in the public docket at
www.regulations.gov . To find the correct docket and documents associated with it,
select the Advanced Search function, and then select Docket Search. Enter the Docket
Number OPP-2005-0231 in the Docket ID field and submit. Click on the Docket ID link,
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and icons for viewing and downloading the supporting documents will appear. Your
computer's "pop-up blocker" function must be turned off for you to view or download
documents in the docket.
This section also summarizes the alternatives and benefits information the Agency
has developed for consideration in the metaldehyde reregistration decision. The
alternatives assessment is also available in the public docket at www.regulations.gov .
The purpose of this section is to help the reader better understand the risk
management decisions reached by the Agency.
A.
Human Health Risk Assessment
The complete metaldehyde human health risk assessment is found in the
document "Metaldehyde: HED Chapter of the Reregistration Eligibility Decision
Document," dated April 3, 2006, and can be accessed via www.regulations.gov as
described above.
The Agency's assessment utilizes submitted and other data to evaluate the
toxicology, product and residue chemistry, dietary exposure, and occupational and
residential exposure associated with metaldehyde. The Agency has determined that these
data are adequate to support a reregistration decision.
1. Acute Toxicity
Acute toxicity data for on metaldehyde are summarized in Table 2.
Table 2. Acute Toxicity Profile
Guideline
No, . "
870.1100
870.1200
870.1300
870.2400
870.2500
'; ' ' ' Study Type
Acute oral [rat]
Acute dermal [rat]
Acute inhalation [rat]
Acute eye irritation [rabbit]
Acute dermal irritation [rabbit]
"MRiD"
00131435
00131434
00131429
42068801
00131971
" '' ' ; Results-' ' ' .,
LD50 = 283 mg/kg
LD50 = >5000 mg/kg
LC50 = 314mg/L/4hrs
mild irritant
not an irritant
Toxicity .
Category.
II
III
IV
III
IV
2. FQPA Safety Factor
FQPA directs EPA, in setting pesticide tolerances, to use an additional tenfold
(10X) margin of safety to take into account potential pre- and postnatal toxicity and
completeness of the data with respect to exposure and toxicity to infants and children.
FQPA authorizes EPA to modify this tenfold safety factor only if reliable data
demonstrate that the resulting level of exposure will be safe for infants and children.
EPA has determined that the FQPA safety factor must be retained for metaldehyde to
account for database uncertainties.
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Neurological effects are suggested by clinical signs observed in studies in dogs
and rats exposed to metaldehyde, including ataxia, twitching, tremors, and hindlimb
paralysis. Developmental toxicity and 2-generation reproduction studies in rats and
rabbits do not demonstrate an increased sensitivity or susceptibility in developing fetuses.
Based on the observation of clinical signs indicating neurotoxicity in several studies, the
Agency is requiring a developmental neurotoxicity study for metaldehyde. Because data
on potential neurotoxic effects on the developing fetus are outstanding, the Agency is
retaining the 10X safety factor for assessment of dietary, residential, and aggregate risks.
3. Endpoint Selection
Table 3 shows endpoints used in the metadehyde human health risk assessment.
Table 3. Toxicology Endpoint Selection
Exposure %eji§rio
Acute Dietary
(All populations)
Chronic Dietary
(All populations)
Residential Short-
Term Incidental Oral
(duration of
exposure:
1-30 days)
Residential
Intermediate-Term
Incidental Oral
(duration of
exposure:
1-6 months)
Short-Term
Inhalation
(duration of exposure
1 - 30 days)
PfQAEL
75 mg/kg/day
10 mg/kg/day
30 mg/kg/day
10 mg/kg/day
30 mg/kg/day
(Inhalation
absorption rate
= 100%)
TJncertaipty Factors;
Level ofiQqucerft?'
10X interspecies,
10X intraspecies,
10X FQPA
(1000X total);
aPAD = 0.075
mg/kg/day
10X interspecies,
10X intraspecies,
10X FQPA
(1000X total)
cP AD = 0.01 mg/kg/day
10X interspecies,
10X intraspecies,
10X FQPA
(1000X total)
MOE = 1000
Residential
10X interspecies,
10X intraspecies,
10X FQPA
(1000X total)
MOE = 1000
ptudj ty pej
,^Test/s^ecfes;;T».oMtc Effects *
'-. ' (MI^Dff) /
Developmental toxicity; rats;
LOAEL =150 mg/kg/day
(mortality, ataxia, tremors,
twitching, rapid respiration,
decreased weight gain, 9s)
(MRID41656001)
Chronic oral toxicity; dogs;
LOAEL = 30 mg/kg/day
(mortality, atrophy of the
testes and prostate)
(MRID 46378401)
Chronic oral toxicity ;dogs;
LOAEL = 90 mg/kg/day
(clinical signs beginning
Week 1)
(MRID 46378401)
Chronic oral toxicity; dogs;
LOAEL = 30 mg/kg/day
(mortality, atrophy of testes
and prostate)
(MRID 46378401)
Chronic oral toxicity; dogs;
LOAEL = 90 mg/kg/day
(clinical signs beginning
Week 1)
(MRID 46378401)
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EJjtpOjiufe Scenario :
Intermediate-Term
Inhalation
(duration of exposure
1-6 months)
Long-Term
Inhalation (duration
of exposure > 6
months)
Dermal
Cancer
NQAEL
10 mg/kg/day
(Inhalation
absorption rate
= 100%)
10 mg/kg/day
(Inhalation
absorption rate
= 100%)
.Upcertghity Factors!
LfTd'ofConcertt-
Occupational
10X interspecies,
10X intraspecies
(100X total)
MOE = 100
Residential
10X interspecies,
10X intraspecies,
10X FQPA
(1000X total)
MOE = 1000
Occupational
10X interspecies,
10X intraspecies
(100X total)
MOE = 100
Residential
10X interspecies,
10X intraspecies,
10X FQPA
(1000X total)
MOE = 1000
Occupational
10X interspecies,
10X intraspecies
(100X total)
MOE = 100
Sta%/type;
Test species-; Twic Effects
' '/ ' (MKfolf
Chronic oral toxicity; dogs;
LOAEL = 30 mg/kg/day
(mortality, atrophy of the
testes and prostate)
(MRID 46378401)
No toxicological endpoint of concern is identified for dermal exposures
Weight of evidence is suggestive of carcinogenic potential.
NOAEL = no observed adverse effect level, LOAEL = lowest observed adverse effect level, PAD =
population adjusted dose (a = acute, c = chronic), MOE = margin of exposure
Because the Agency could not identify an endpoint for dermal exposures, it did
not conduct an assessment of the risk associated with dermal exposures in any exposure
scenario (residential, occupational). As a matter of policy, the Agency does not quantify
pesticide cancer risks when the evidence for carcinogenicity is "suggestive." In the case
of metaldehyde, incidence of benign liver tumors was increased in both sexes of the
mouse. Although the increased incidence of benign liver tumors in female rats relative to
controls was statistically significant, it was just slightly higher than the upper end of the
range for historical controls at the testing facility. No tumors were found in male rats in
the same study. The mutagenicity data for metaldehyde are deficient and new data are
required, but examination of the old data suggests that metaldehyde is not a mutagen.
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4. Dietary Exposure and Risk from Food and Drinking Water
The dietary risk assessment is a function of both exposure and toxicity. In the
case of metaldehydye, dietary risk is expressed as a percentage of a level of concern. The
level of concern is the dose predicted to result in no unreasonable adverse health effects
to any human population subgroup, including sensitive members of such population
subgroups. This level of concern is referred to as the population adjusted dose (PAD).
Risk estimates less than 100% of the PAD are below EPA's level of concern. The acute
PAD (aPAD) is the highest predicted dose to which a person could be exposed on any
given day with no adverse health effect expected. The chronic PAD (cPAD) is the
highest predicted dose to which a person could be exposed over the course of a lifetime
with no adverse health effects expected.
a) Drinking Water Concentrations
Drinking water concentrations of metaldehyde were estimated for both surface
water and groundwater. Scenarios are modeled by the Agency for reasonable worst-case
exposures. The drinking water assessment is detailed in the document entitled "Second
Amended Tier II Estimated Drinking Water Concentrations (Surface and Ground Water)
of the Molluscicide Metaldehyde," December 12, 2005, posted to the metaldehyde docket
at www.regulations.gov. For surface water, estimated drinking water concentrations
(EDWCs) were generated from a Tier IIPRZM-EXAMS - Index Reservoir model based
on the use of metaldehyde on cole crops and leafy vegetables in Florida and California.
For groundwater, EDWCs were generated from a Tier I SCI-GROW analysis, based on
use of metaldehyde on ornamental plants. Estimated drinking water concentrations for
metaldehyde are provided in Table 4; values in bold were used in the dietary assessment.
Table 4. EDWCs for Metaldehyde
Source
Surface water
Groundwater
Scenario
Cole crops, FL
Leafy vegetables, CA
Ornamentals
Acute EDWC
110 ppb
94.8 ppb
Chronic EDWC
8.4 ppb
55.8 ppb
62.5 ppb
b) Food + Water Exposures
An unrefined Tier 1 acute dietary exposure assessment was conducted for all
supported metaldehyde food uses based on upper-bound pesticide residue inputs (e.g.,
assuming 100% of registered crops are treated with metaldehyde and that residues are
present at tolerance levels). For Tier 1 analyses, EPA presents results at the 95th
percentile of exposure, which provides a high-end estimate of risk that is protective of
human health. Dietary risk estimates are calculated for exposures to the general U.S.
population and subpopulations from food and both surface water and ground water
together.
c) Acute Dietary (Food and Drinking Water) Risk
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For the general population and all subpopulations, acute dietary risk estimates are
below 100% of the aPAD. Dietary risk estimates for the general population and the most
highly exposed subpopulation are shown in Table 5 below.
d) Chronic Dietary (Food and Drinking Water) Risk
For the general population and all subpopulations, chronic dietary risk estimates
are below 100% of the cPAD. Dietary risk estimates for the general population and the
most highly exposed subpopulation are shown in Table 5.
Table 5. Summary of Food + Water Dietary Risk Estimates for Metaldehyde
Population
General
Children
1-2 years old
Acute Risk; Food +
Surface Water
12% aPAD
26% a PAD
Groundwater
14% aPAD
29% aPAD
Chronic Risk; Food +
Surface Water
29% cPAD
59% cPAD
Groundwater
35% cPAD
69% cPAD
5. Residential Exposure and Risk
Residents can be exposed to metaldehyde used on lawns, and ornamental,
vegetable, and fruit plants as a result of both application and post-application activities,
on a short -term exposure basis. Non-cancer risks are calculated by the margin of
exposure (MOE) approach which relies on the ratio of the dose from a toxicological
endpoint selected for risk assessment to the predicted exposure. Risk estimates are
compared to levels of concern which reflect the endpoint and all relevant uncertainty
factors. In this case, MOEs of greater than 1000 do not represent risks of concern. Since
no dermal endpoint of concern has been identified for metaldehyde, dermal risks were not
estimated. Intermediate- and long-term exposures are not expected for residential
handlers because of the sporadic nature of applications by homeowners.
a) Residential Handlers
Metaldehyde is available in residential-use products s in the following
formulations: liquid concentrate, ready-to-use liquid/paste, and ready-to-use
granules/pellets/minipellets/meal baits. Most of the residential consumer products are
formulated as granular baits. Methods of application include hose-end sprayers, trigger-
pump sprayers, low pressure handwand sprayers, sprinkler cans, belly grinders, push-type
spreaders, and applying ready-to-use products by hand. The Agency assessed eight
residential handler short-term exposure scenarios, representing a range of possible
exposures. MOEs for all of the residential handler scenarios assessed are greater than the
target MOE of 1000, ranging from 56,000 to 6,000,000. The high MOEs result in part
from application methods that do not create small droplets (of respirable size), the low
volatility of metaldehyde, and dilution by ambient air. The Agency has determined that
risks to residential handlers of metaldehyde are not of concern.
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b) Residential Post-Application Exposure and Risk
Individuals potentially can be exposed to metaldehyde after application when they
do yard or garden work or play within treated areas. No dermal endpoint has been
identified for metaldehyde, and significant residential post-application inhalation
exposures are not anticipated for metaldehyde, because of its limited volatility and
dilution by ambient air. The Agency did assess the potential post-application risk for
toddlers who play on treated turf and may be exposed through hand-to-mouth activities,
object-to-mouth activities, and ingestion of treated soil. Short-term MOEs from these
oral exposures are greater than 1000, with an MOE for exposure by all three routes
together of 1600 on the day of application. These MOEs do not represent risks of
concern.
The Agency also assessed risks associated with the direct ingestion of
metaldehyde granular materials by toddlers. MOEs for ingestion of two different
formulation types are estimated to be well below the target MOE of 1000, at 188 and 50.
The Agency also determined that very low numbers of granules could result in exposures
at the level of concern, depending on the size of the granules (estimated at 2 to 15
granules for the two formulations). A review of data from the American Association of
Poison Control Centers (AAPCC) shows that a total of 1648 poisoning incidents in
children were recorded for metaldehyde in the years 1993 through 2003. The most recent
year for which data are available from the AAPCC is 2004, when 244 accidental
exposures to metaldehyde were reported, with 105 incidents occuring in children younger
than 6 years old. None of the reported incidents were associated with life-threatening
conditions. Twenty-nine incidents were associated with minor symptoms that resolved
quickly, and three were associated with more pronounced symptoms that had no residual
ill effect.
Beginning in 2001, a bittering agent, denatonium benzoate, was added to
metaldehyde home and garden products at a rate of 30 ppm. In late 2003, the
concentration of denatonium benzoate was increased to 300 ppm. Denatonium benzoate
is used in rodenticides and appears to be effective in deterring ingestion by children at a
concentration of 300 ppm. As discussed below, the evidence for its effectiveness in dogs
is less conclusive. Because consumer product may remain on store shelves and in the
hands of consumers for a year or more, the industry believes that metaldehyde products
containing the higher level of denatonium benzoate are beginning to dominate the market
this year, so that the impact of the new formulation would not be evident in data from
2004.
Given the movement of product with the higher concentration of denatonium
benzoate into the consumer market, the Agency believes that ingestion by toddlers of
metaldehyde granules is unlikely, and that if ingestion occurs, the bitter taste would cause
a toddler to spit out the material quickly, thus limiting exposure. Home and garden
products containing metaldehyde already are labeled to require that users keep children
out of areas where the product is stored or used, but the Agency believes that it is
nevertheless prudent to require that this labeling be enhanced for visibility and content.
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The Agency will continue to monitor poisoning data as the new mitigation comes into
effect.
6. Aggregate Exposure and Risk
The FQPA amendments to the Federal Food, Drug and Cosmetic Act (FFDCA,
Section 408(b)(2)(A)(ii)) require "that there is a reasonable certainty that no harm will
result from aggregate exposure to the pesticide chemical residue, including all anticipated
dietary exposure and other exposures for which there is reliable information." In
response to this requirement, the Agency conducts aggregate risk assessments to account
for all potential non-occupational exposures when developing its reregistration decisions.
a) Acute Aggregate Risk
Only food and water exposures to metaldehyde are aggregated for this acute
assessment. This assessment is described above and summarized in Table 5.
b) Short-Term Aggregate Risk
Dietary (food + water) exposures and post-application incidental oral exposures
are aggregated for short-term exposures to metaldehyde. The dietary risk component is
summarized in Table 5. Incidental oral exposures may result from children playing on
treated turf and ingesting soil or inserting their hands in their mouths while playing or
after playing on treated turf. Since these activities may occur simultaneously, the
combined MOE is used in the aggregate assessment. Adult residential exposures are
estimated to be greatest for handlers; these adult exposures are aggregated with dietary
exposures. The target MOE for all short-term aggregate risks is 1000 for all scenarios.
All aggregate MOEs for short-term exposure to metaldehyde are 1200 or greater, and so
are not of concern. Short-term aggregate exposures and risk estimates are shown in
Table 6.
Table 6. Short-term Aggregate Risk Estimates for Metaldehyde
Population
Exposure, mg/kg/day
Residential
Food + Water
Aggregate MOE
Residential + Food + Water
Surface water source for drinking water
Children
Adults
0.019
0.00054
0.0059
0.0029
1200
8700
Groundwater source for drinking water
Children
Adults
0.019
0.00054
0.0069
0.0035
1200
7400
c) Chronic Aggregate Risk
Only food and water exposures to metaldehyde are aggregated for this chronic
assessment, because there are no long-term residential exposures expected for
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metaldehyde. This chronic dietary (food + water) assessment is described above and
summarized in Table 5.
7. Cumulative Risk
Unlike other pesticides for which EPA has followed a cumulative risk approach
based on a common mechanism of toxicity, EPA has not made a common mechanism of
toxicity finding for metaldehyde and any other substances, and metaldehyde does not
appear to produce a toxic metabolite produced by other substances. For the purposes of
this reregistration eligibility and tolerance action, EPA has not assumed that metaldehyde
has a common mechanism of toxicity with other substances. For information regarding
EPA's efforts to determine which chemicals have a common mechanism of toxicity and
to evaluate the cumulative effects of such chemicals, see the policy statements released
by EPA's Office of Pesticide Programs concerning common mechanism determinations
and procedures for cumulating effects from substances found to have a common
mechanism on EPA's website at http://www.epa.gov/pesticides/cumulative/.
8. Risk to Domestic Animals from Ingestion of Metaldehyde
Granules in Residential Settings
Information from several sources indicates that there are a considerable number of
poisonings of domestic animals, especially dogs, resulting from ingestion of
metaldehyde, typically after such materials are used around the home, but occasionally
when pets eat granules after tearing into or opening product containers.
For the years 2000-2004, NPIC, a toll-free telephone service that provides
pesticide information without treatment advice to the general public and medical and
veterinary professionals, collected data from reports of 104 cases (probable exposure to
metaldehyde) and 156 cases (possible exposure) involving 274 animals. Most of the
metaldehyde incidents reported to NPIC were dogs (92%). All but one of the remaining
incidents was reported for cats. The number of probable cases increased yearly from 8 in
2000 to 43 in 2004. Numbers of possible cases held steady in 2000-2003 but increased in
2004. Most cases involved animals exposed via ingestion after metaldehyde applications
to yards and gardens. Granular and bait formulations were most commonly ingested. For
cases in which the outcome was reported, seventeen animals in the probable and five in
the possible categories died, while 10 animals in the both categories combined recovered.
NPIC refers callers reporting animals in need of immediate veterinary care to the
ASPCA's Animal Poison Control Center (APCC).
The APCC maintains a 24-hour emergency hotline for animal poisoning
incidents, similar to the services provided by human poison control centers. A
representative of the APCC, in private communications with the Agency, has indicated
that the APCC receives incident reports of "possible" to "observed" exposure certainty
for metaldehyde on an annual basis in greater numbers than NPIC does for its analogous
probable and possible exposure categories. In the two-year period 2004 through 2005,
APCC handled almost 500 cases (an average of 250 cases/year for APCC vs. 65/year for
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NPIC). The greater number of calls received by the APCC likely is attributable to several
factors, including referral of NPIC callers to APCC, contracting by a subset of
metaldehyde manufacturers directly to APCC for responding to incidents associated with
their products and greater name recognition for the APCC among callers not obtaining
telephone numbers from product labels. The APCC further advised the Agency that it
considers metaldehyde calls as "immediate interrupts," warranting termination of data
collection followed by immediate referral to veterinarians, because of the imminent
hazard to the exposed animal.
Lonza, the registrant of technical grade metaldehyde, maintains a set of
"Minimum Quality Requirements" (MQRs) with its formulators of home and garden
products. One of the MQRs requires formulators to incorporate denatonium benzoate, a
bittering agent, into their residential metaldehyde products, for the purpose of making the
products unpalatable to children and domestic animals that might otherwise be attracted
to and ingest the granules. Lonza originally required the incorporation of 30 ppm of
denatonium benzoate into these products. In late 2003, the rate was increased to 300
ppm. Denatonium benzoate is a proven aversion agent for children and is used in
rodenticides. The Agency has reviewed data that Lonza believes supports the efficacy of
denatonium benzoate in preventing ingestion of metaldehyde granules by dogs, but is
unable to determine the efficacy because of limitations in study design. Although
denatonium benzoate appears to be an effective aversion agent for children, dogs are
likely to be less sensitive to the taste, or at least less selective in what they eat, than
children.
9. Occupational Risk Assessment
a) Handler exposures
Occupational handlers of metaldehyde may be exposed during mixing (for
products which are diluted before application), loading, or applying metaldehyde
products, or through a combination of these activities. Other workers may be exposed to
metaldehyde when entering areas where metaldehyde previously has been applied.
The Agency believes that occupational handlers may be exposed to metaldehyde
on a short-term (up to 30 days) or intermediate-term (30 days to several months) basis.
The Agency's occupational handler risk assessment is based on 16 different scenarios
defined by different handling tasks (e.g., mixer/loader, applicator) and application
methods (e.g., liquids via airblast, granulars via tractor-drawn spreader). In the absence
of a dermal toxicity endpoint, only inhalation exposures are assessed. The Agency
assessed each of the 16 scenarios for increasing levels of inhalation protection from
baseline PPE (handlers wearing long-sleeve shirts, long pants, shoes, socks, and no
resprirator) to Engineering Controls (a closed tractor cab or closed loading system).
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b) Handler risks
For all short- and intermediate-term occupational handler scenarios, risks are not
of concern even at the baseline level of personal protection, without a respirator (i.e., all
MOEs are greater than the target MOE of 100). The lowest MOE at baseline, 790, is
associated with mixing and loading liquid concentrates to support application via
chemigation; most scenarios are associated with MOEs in the thousands.
c) Occupational post-application risks
Occupational post-application exposures were not assessed for metaldehyde
because no dermal hazard was identified and inhalation exposures are assumed to be
negligible in outdoor post-application scenarios due to metaldehyde's low vapor pressure
and dilution in outdoor air. Post-application inhalation exposures for indoor spaces (i.e.,
greenhouses) are also assumed to be minimal because the Worker Protection Standard for
Agricultural Pesticides requires that greenhouses be well-ventilated following pesticide
application. The current restricted entry intervals (REIs) specified on various
metaldehyde labels range from 12 to 24 hours. The results of this assessment do not
impact the current REIs.
B. Environmental Risk Assessment
The complete metaldehyde environmental risk assessment is found in the
document "Level 1 Screening Ecological Risk Assessment for the Reregistration of
Metaldehyde," March 30, 2006, and can be accessed via www.regulations.gov as
described above.
1. Environmental Fate and Transport
Metaldehyde is highly mobile in soils, and is generally stable to abiotic
degradation mechanisms such as hydrolysis and photolysis. Metaldehyde is primarily
dissipated from soils through biodegradation under aerobic conditions, with a half-life of
approximately 2 months. Under anaerobic conditions, the half-life of metaldehyde is
much higher (>200 days). Its low vapor pressure and Henry's Law constant indicate that
volatilization from soils and water surfaces will not be an important transport process. In
addition, the results of a laboratory volatility study suggest that volatilization losses from
soil surfaces will be minor.
Acetaldehyde is the primary degradation product of metaldehyde. Acetaldehyde
is a relatively short-lived metabolite in the environment, and is readily oxidized to acetic
acid and ultimately to carbon dioxide and water.
2. Ecological Risk
The Agency's ecological risk assessment compares toxicity endpoints to
estimated environmental concentrations (EECs) modeled from environmental fate
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characteristics and pesticide use parameters. To evaluate the potential risk to non-target
organisms from the use of metaldehyde products, the Agency calculates a Risk Quotient
(RQ), which is the ratio of the EEC to the most sensitive toxicity endpoint values, such as
the median lethal dose (LDso) or the median lethal concentration (LCso). These RQs are
then compared to Levels of Concern (LOCs) established by the Agency for interpreting
potential risk to non-target organisms and the need for regulatory action. When the RQ
exceeds the LOG for a particular category, the Agency presumes a risk of concern. These
risks of concern may be addressed by further refinements of the risk assessment or
mitigation measures. The Agency further considers levels of uncertainty in the
assessment and any reported incidents to non-target terrestrial or aquatic organisms in the
field (e.g., fish or bird kills) when characterizing risk.
Table 7. EPA's Levels of Concern and Associated Risk Presumptions
IF...
THEN the Agency presumes...
Mammals and Birds
The acute RQ > LOG of 0.5
The acute RQ > LOG of 0. 1
The chronic RQ > LOG of 1
Acute risk to Federally-listed and non-listed species
Acute risk to Federally-listed species
Chronic risk to Federally-listed and non-listed species
Fish and Aquatic Invertebrates
The acute RQ > LOG of 0.5
The acute RQ >LOC of 0.05
The chronic RQ > LOG of 1
Acute risk to Federally-listed and non-listed species
Acute risks to Federally-listed species
Chronic risk to Federally-listed and non-listed species
Terrestrial and Aquatic Plants
The acute RQ > LOG of 1
Acute risk to Federally-listed and non-listed species
a) Risk to Aquatic Organisms
(1) Toxicity to Fish and Aquatic Invertebrates
The results of acute toxicity studies with a surrogate freshwater fish (rainbow
trout) show that metaldehyde is slightly toxic to freshwater fish on an acute basis. No
acute toxicity data with estuarine/marine fish are available for metaldehyde.
In an acute toxicity study for a freshwater invertebrate (Daphnia magna), no
treatment-related effects were observed at the highest concentration of metaldehyde
tested. No acute toxicity data with estuarine/marine invertebrates are available for
metaldehyde.
No chronic toxicity data are available for metaldehyde in freshwater fish and
invertebrates. No toxicity data are available for acute or chronic exposures to
estuarine/marine fish or invertebrates, or aquatic plants. No data on toxicity of
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metaldehyde to non-target, aquatic mollusks are available. Toxicity data for aquatic
organisms exposed to metaldehyde are summarized in Table 8.
Table 8. Metaldehyde Toxicity Values (mg ai/L) for Aquatic Organisms
Exposure
Scenario
Species
Freshwater Fish
Acute
Chronic
Rainbow trout
Exposure Acute LC/E
Duration Chronic NO
96 hours LCso = 69 mj
CSQ or Reference
AEC (Classification)
I ai/L MRID 42044004
(Supplemental)
No data acceptable for quantitative risk assessment are available
Freshwater Invertebrates
Acute
Chronic
Water flea
48 hours LC50 >77.66
mg ai/L MRID 42044005
(Supplemental)
No data acceptable for quantitative risk assessment are available
Estuarine/Marine Fish
Acute
Chronic
No data acceptable for quantitative risk assessment are available
Estuarine/Marine Invertebrates
Acute
Chronic
No data acceptable for quantitative risk assessment are available
Aquatic Plants
Acute
Chronic
No data previously required
(2) Exposures of Aquatic Organisms to Metaldehyde
Exposure to aquatic organisms is assumed to occur through direct contact with
contaminated surface water. The estimated environmental concentrations (EECs) of
metaldehyde to which aquatic organisms can be exposed are generated using the Tier 1
model GENEEC2 (Generic Estimated Environmental Concentration). Maximum
application rates and use patterns for citrus, brassica (cole crops), leafy vegetables
(lettuce), strawberries, berries, artichokes, turf, and ornamentals are inputs to the model.
The GENEEC2 model uses soil/water partition coefficients and degradation kinetic data
to estimate run-off from a theoretical ten hectare field into a 1-hectare by 2-meter deep
"standard" pond. This Tier I model uses conservative inputs such as maximum
application rates and maximum number of applications from product labels, resulting in
conservative exposure estimates. EECs represent the one-in-ten year concentrations so
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that actual environmental concentrations are only expected to exceed the GENEEC-
generated values once in ten years. Peak EECs used in the acute risk assessment for
aquatic wildlife are shown in Table 9 below.
(3) Fish and Aquatic Invertebrate Risk Estimates
Acceptable toxicity studies on metaldehyde are only available for acute exposure
to freshwater fish and invertebrates. RQs were not calculated for freshwater invertebrates
since no mortalities were observed at the highest dose tested in Daphnia. Acute RQs for
freshwater fish are summarized in Table 9. No acceptable toxicity data are available to
assess acute risks to marine/estuarine fish and invertebrates, chronic risks to freshwater
fish and risks to marine/estuarine fish, invertebrates, and aquatic plants.
Since no toxicity information is available for degradates of metaldehyde, RQs
were derived only for the parent compound.
Table 9. Acute RQs for Freshwater Fish Exposed to Metaldehyde
Use Site
Artichokes
Berries
Brassica (cole crops)
Citrus
Strawberries
Grass grown for seed
Dichondra / Turf
Ornamentals
Peak EEC
(ug ai./L)
238
185
189
271
145
292
422
1480
Acute RQ
(EEC/LC50)
0.003
0.003
0.003
0.004
0.002
0.004
0.006
0.021
Acute RQs for freshwater fish are below the acute risk LOG (0.5) and the acute
risk LOG for endangered species (0.05) for each of the use sites modeled.
(4) Risks to Aquatic Plants
No toxicity data are available to assess risk to aquatic plants. No adverse
ecological incidents have been reported with regard to metaldehyde and aquatic plants.
The Agency is requiring toxicity data for aquatic plants.
b) Terrestrial Risk
(1) Toxicity to Terrestrial Wildlife
Available data on the acute toxicity for terrestrial animals indicate that
metaldehyde is moderately toxic to mammals and slightly to moderately toxic to birds on
an acute exposure basis. Acute toxicity data for the rat are selected as the basis of the
mammalian wildlife risk assessment. The endpoint for Japanese quail was selected as the
basis of the avian acute risk assessment.
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For the chronic assessments, parental systemic toxicity and toxicity to offspring
are identified as the endpoint for mammalian wildlife. For birds, the chronic endpoint is
based on reproductive effects (reductions in the ratios of number hatched to eggs laid, to
eggs set, and to live embryos; and reduction in the ratio of hatchling survival to eggs set),
as observed in a study conducted with mallard ducks.
Endpoints selected for the terrestrial assessment are shown in bold in Table 10.
Table 10. Metaldehyde Toxicity Values for Terrestrial Organisms
Exposure
Scenario
Species
Study Type
Toxicity Value
MRID#
Mammals
Acute
Dose-based
Chronic
Rat
Rat
Single oral
dose
reproduction
LD50(?) = 398 mg/kg
NOAEC = 1000 mg/kg
diet
NOAEL = 65 mg/kg
bwt/day
00131435
42823101
Birds
Acute
Dose-based
Acute
Dietary-based
Chronic
Dietary-based
Japanese
quail
Peking
duck
Mallard
duck
Single oral
dose
5 -day dietary
reproduction
LD50 = 181 mg./kg
LC50= 2,668 mg./kg
NOAEC <49 mg/kg diet
41553201
(Supplemental)
41553204
(Supplemental)
42867902
(Supplemental)
(2)
Other Terrestrial Wildlife
Predictably, toxic effects have been observed in clinical studies of snails and
slugs, and have also been observed in the carabid beetle. Toxicity to earthworms appears
to be low. None of these studies provide sufficient data for a quantitative risk analysis
for other terrestrial animals.
(3)
Terrestrial Plants
There are no toxicity data available for assessing risks to terrestrial plants.
Metaldehyde is used to protect a wide variety of plant types. No adverse ecological
incidents gave been reported with regard to metaldehyde and terrestrial plants. The
Agency is requiring toxicity data for terrestrial plants.
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(4) Potential Exposures for Terrestrial Wildlife
The Agency assessed potential exposures to terrestrial wildlife from the granular
applications to all the supported uses of metaldehyde using the T-REX model. Input
parameters to the model are summarized in Table 11.
Table 11. Input Parameters for Terrestrial EECs from Granular Applications
Input Variable
Parameter Value
Source
Maximum
application rate
Artichokes: 0.8 Ib ai/acre
Berries: 0.8 Ib ai/acre
Cole crops: 1.0 Ib ai/acre
Citrus crops: 1.0 Ib ai/acre
Grass grown for seed: 1.61bai/A
Strawberries: 1.0 Ib ai/acre
Dichondra/turf: 1.0 Ib ai/acre
Ornamentals: 3.5 Ib ai/acre
Registrant commitment
Maximum number of
applications per year
Artichokes: 7
Berries: 5
Cole crops: 4
Citrus crops: 6
Grass grown for seed: 4
Strawberries: 3
Dichondra/turf: 12
Ornamentals: 12
Registrant commitment
Minimum application
interval
Artichokes: 18 days
Berries: 14 days
Cole crops: 14 days
Citrus crops: 14 days
Grass grown for seed: 21 days
Strawberries: 14 days
Dichondra/turf: 21 days
Ornamentals: 21 days
Product Labels
Foliar half-life
35 days
T-REX Default
100%
T-REX Guidance
Inputs for the
LDso/ft2 Method for
Granular Applications
to Soil
Application method: broadcast
Product Label
Formulation type: granular
Product Label
Exposure estimates are based on the assumption that 100% of the applied granules
will be present on the surface of the soil. A summary of acute EECs generated by T-REX
for granular applications of metaldehyde is presented in Table 12. The Agency currently
has no standard methodology for assessing chronic exposures to terrestrial organisms
from granular applications.
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Table 12. Terrestrial EECs for Granular Applications
Use Site
Artichokes
Berries
Cole crops
Citrus crops
Grass grown for seed
Strawberries
Dichondra/Turf
Ornamental Plants
EEC (mg ai
./ft2)
8
8
10
10
17
10
10.4
36.4
(5) Terrestrial Risk Estimates
Acute RQs for granular broadcast applications of metaldehyde are derived by
dividing the acute LDso values for birds and mammals by the application rate expressed
in terms of mg ai/ft2. These RQs are shown in Table 13.
Table 13. Acute RQs for Birds and Mammals
Use Site
Artichokes
Berries
Cole crops
Citrus
Grass grown for
seed
Strawberries
Birds
Body Weight
20 g
100 g
1000 g
20 g
100 g
1000 g
20 g
100 g
1000 g
20 g
100 g
1000 g
20 g
100 g
1000 g
20 g
100 g
1000 g
Acute RQ
(LD50/ft2)
3.05*
0.48**
0.03
3.05*
0.48**
0.03
3.81*
0.6*
0.04
3.81*
0.6*
0.04
6.09*
0.96**
0.07
3.81*
0.6*
0.04
Mammals
Body Weight
15 g
35 g
1000 g
15 g
35 g
1000 g
15 g
35 g
1000 g
15 g
35 g
1000 g
15 g
35 g
1000 g
15 g
35 g
1000 g
Acute RQ
(LD50/ft2)
0.66*
0.35 **
0.03
0.66*
0.35 **
0.03
0.82*
0.44 **
0.04
0.82*
0.44**
0.04
1.32*
0.7**
0.06
0.82*
0.44 **
0.04
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Use Site
Dichondra/ Turf
Ornamentals
Birds
Body Weight
20 g
100 g
1000 g
20 g
100 g
1000 g
Acute RQ
(LD50/ft2)
3.81*
0.6*
0.04
13.33*
2.09*
0.15**
Mammals
Body Weight
15 g
35 g
1000 g
15 g
35 g
1000 g
Acute RQ
(LD50/ft2)
0.82*
0.44**
0.04
2.89*
1.53*
0.12**
**
RQs exceed the acute risk LOG for birds and mammals and for endangered
species ("the acute risk LOG," RQ > 0.5)
RQs exceed the acute risk LOG for endangered species (RQ >0.1)
Results of this screening level analysis indicate that small- and medium-sized
birds and mammals may be at acute risk from exposure to granular applications. For all
use sites, the acute RQs for the smallest birds exceed the acute risk LOG. For all use sites
except artichokes and berries, acute RQs for the medium-sized birds exceed the acute risk
LOG; for artichokes and berries, they exceed the acute risk LOG for endangered species.
For ornamentals, the acute risk LOG for endangered species is exceeded for the largest
birds.
For all use sites, acute RQs for the smallest mammals exceed the acute risk LOG.
For medium-sized mammals, the acute risk LOG for endangered species is exceeded for
all sites; for ornamentals, the acute risk LOG is also exceeded. The RQ for the largest
mammals associated with applications to ornamentals exceeds the acute risk LOG for
endangered species.
The Agency does not have standard procedures for estimating chronic risk to
terrestrial wildlife from exposure to granular formulations. Thus, chronic risks to birds
and mammals from granular applications of metaldehyde are not assessed.
c) Endangered Species
Risk quotients for metaldehyde, derived from a screening level analysis, indicate
a potential for acute risks to endangered (listed) terrestrial species associated with
granular applications to the modeled use sites, as noted below:
Birds (also representing potential risks to reptiles and terrestrial-phase amphibians)
Acute RQs exceed the LOG for listed species for small- and medium-sized birds
in artichokes, berries, cole crops, citrus, grass grown for seed, strawberries, and
dichondra/turf
Acute RQs exceed the LOG for listed species of all sizes of birds in ornamentals
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Mammals
Acute RQs exceed the LOG for listed species for small- and medium-sized
mammals in artichokes, berries, cole crops, citrus, grass grown for seed,
strawberries, and dichondra/turf
Acute RQs exceed the LOG for listed species of all sizes of birds in ornamentals
Chronic risks were not assessed for terrestrial wildlife because the Agency lacks a
methodology for assessing chronic exposures associated with direct ingestion of granules,
so chronic risks to endangered birds and mammals cannot be ruled out. In addition,
toxicity information for metaldehyde is lacking on acute and chronic effects on
marine/estuarine fish and invertebrates (including mollusks), chronic effects on
freshwater fish and invertebrates, and aquatic and terrestrial plant toxicity. Risks to these
taxa cannot be precluded, and there is a potential for direct effects to Federally-listed
species in these taxa. Furthermore, potential indirect effects to any species dependent
upon species that experience effects from the use of metaldehyde can not be precluded
based on the screening level ecological risk assessment conducted for this RED. These
findings are based solely on EPA's screening level assessment and do not constitute
"may affect" findings under the Endangered Species Act.
To address concerns about risks to endangered species from pesticide use, the
Agency has developed the Endangered Species Protection Program (ESPP). The
assessments of risk for aquatic and terrestrial wildlife described in this RED serve as a
screening tool to determine the need for any species-specific assessments for listed
species, in accordance with the ESPP. Such assessments would refine the screening level
assessment by taking into account such factors as the geographic areas of pesticide use in
relation to the listed species and the habits and habitat requirements of the listed species.
If the Agency's species-specific assessments result in the need to modify the use of the
pesticide in specific geographic areas, those changes will be undertaken through the
process described in the Agency Federal Register Notice (54 FR 27984) on
implementation of the ESPP.
C. Alternatives Assessment and Related Information
The Agency solicited information about critical uses and alternatives from the
public and from the Regional IPM Centers and their field and academic contacts through
the USDA's Office of Pest Management Policy. Additional information was gleaned
from the IPM Centers' Crop Profiles (located at www.ipmcenters.org/CropProfiles/ ).
Comments were received on the critical need for metaldehyde in some of the
agricultural and commercial crops assessed for this RED (especially strawberries,
caneberries, citrus, and production ornamentals) and in some of the crops currently on
product labels but not supported by the registrant. Respondents also reported on
alternatives to metaldehyde that are used and may be efficacious for various use sites
iron phosphate for home lawns and parks, and for production ornamentals in the North
Central States, and copper bands or sprays for citrus.
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Respondents also mentioned cultural controls that provide adequate or
supplemental controls in certain circumstances, particularly for residential and public
land use. Cultural controls include hand-picking, removal of plant debris that can shelter
slugs and snails, and watering in the morning rather than in the evening (snails and slugs
favor damp conditions and feed at night). Ironically, no-till agriculture can reduce some
pesticide inputs (i.e., herbicides), but can favor development of economically damaging
slug and snail populations in plant debris on the ground. For strawberries and
artichokes, which can be grown as either annuals or perennials, annual culture tends to
reduce snail and slug populations relative to perennial culture so that fewer or no
applications of metaldehyde may be needed.
The Agency conducted an assessment of alternatives for metaldehyde. The
resulting document, entitled "Metaldehyde Alternatives Assessment," July 18, 2006 is
accessible via the docket at www.regulations.gov. In summary, the Agency found that
metaldehyde is the dominant molluscicide for control of snails and slugs in both
agricultural crops and the residential/ornamental environment. Methiocarb is a
Restricted Use carbamate pesticide and is registered only for a subset of the sites where
metaldehyde and iron phosphate can be used: turf, and greenhouse and nursery
ornamentals. Methiocarb has limited usage except in greenhouse ornamentals. Iron
phosphate, a Reduced Risk pesticide, is a newer registration also with limited usage.
Data on the relative efficacy of metaldehyde and iron phosphate for most use
sites are not available; however, the consensus of numerous publications is that efficacy
of iron phosphate is variable in agricultural and production horticulture. Data suggest
iron phosphate generally is somewhat less effective than metaldehyde, but may be used
more effectively under high moisture conditions. In contrast, information received
from Oregon indicates that iron phosphate does not hold up well under wet conditions
in Oregon, suggesting that local environmental conditions may have a large influence
on effectiveness. Growers may be reluctant to use iron phosphate because they consider
it to be new and untested, and because it is more expensive ($1.55/lb vs. $1.25 for
metaldehyde). In addition, non-chemical measures are typically considered to be either
too expensive or too labor intensive for wide-scale use in agriculture.
The Agency believes that for residential use, iron phosphate and non-chemical
control measures may both be acceptable alternatives to metaldehyde. Some
ornamentals growers favor the use of iron phosphate because metaldehyde granules
tend to become moldy; moldy granules are unsightly in pots and on soil surfaces and
stick to the shoes of customers as they walk around greenhouses and retail nurseries.
In addition, the Agency believes that programs relying on the integration of
different methods of slug and snail control (use of metaldehyde and iron phosphate and
cultural methods) can allow a reduction in the number of times metaldehyde is applied.
Experts representing specific grower groups have informed the Agency that the use
parameters supported by Lonza, which are the basis of the Agency's risk assessments,
overstate what is needed for economical control of control slugs and snails in some use
sites. These experts have provided use site-specific information on reduced application
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rates and numbers of applications which provide adequate control. Lonza itself has
indicated that numbers of applications can also be reduced for other uses sites relative to
the parameters it initially cited.
The Agency has considered this information in its development of the risk
mitigation plan for metaldehyde.
IV. Reregistration Decision
A. Risks of Concern and Risk Mitigation
1. Dietary
There are no dietary risks of concern for metaldehyde.
2. Residential
There are no residential risks of concern. MOEs for post-application risk to
toddlers are above the target MOE of 1000; the MOE for combined risk from post-
application exposures is 1600. The Agency expects that the requirement for formulating
metaldehyde home and garden products with a bittering agent (as described below) is
effective in deterring direct ingestion of granules by children. At the same time, the
Agency believes it is prudent to require label language on best practices that provides
residential users with information on how to reduce exposures to children. Labeling
requirements for metaldehyde products are detailed in Table 16.
3. Aggregate
Aggregated risks from dietary and residential exposures are below levels of
concern. Aggregate risk estimates for toddlers are the highest of the aggregate exposures,
with an MOE of 1200. As noted above, the Agency is requiring labeling to address
potential post-application exposures to children.
4. Occupational
None of the occupational scenarios assessed by the Agency posed risks of
concern, even at the baseline level (handlers wearing long-sleeved shirts, long pants,
shoes, and socks, without respirators or gloves). Current labels typically require handlers
to wear long-sleeved shirts, long pants, waterproof gloves (preferably chemically-
resistant), and shoes and socks. Additional PPE may be required based on product label
reviews.
Occupational post-application exposures were not assessed, but are not expected
to pose risks of concern. REIs for metaldehyde products may be revised based on
product label reviews.
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5. General Concerns
All end-use product labels must be amended such that they are consistent with
only those uses determined to be eligible for reregistration. All other uses must be
deleted from all labels.
6. Domestic Animals
Based on the number of poisoning incidents involving ingestion of metaldehyde
products by domestic animals (primarily dogs) after application in residential settings,
and incident information suggesting that dogs also may ingest metaldehyde granules after
opening product packaging, risks to domestic animals are of concern.
The Agency is implementing a performance-based mitigation program for
residential uses of metaldehyde. The Agency believes that this mitigation program will
bring risks below levels of concern. Nevertheless, the Agency will require registrants to
evaluate the program and submit confirmatory data regarding its effectiveness in
reducing numbers of domestic animal incidents and lethal poisoning incidents. If the data
indicate that the risk mitigation program is not effective in reducing the numbers and/or
severity of poisoning incidents among domestic animals, the Agency may require
additional mitigation or the termination of metaldehyde registrations for non-agricultural
uses.
The Agency is specifying a number of label requirements to address the risks to
domestic animals. The required label language is detailed in Table 16. In summary,
labels must be revised to include the following elements:
Labels for residential-use products must prominently display language advising
users that:
dogs and other domestic animals are attracted to metaldehyde products, both in
the package and when applied
metaldehyde ingestion or other exposures to metaldehyde can be lethal to
domestic animals
domestic animals must be excluded from treated areas during and after
application, and until applied material is no longer visible
application of metaldehyde granules is prohibited unless domestic animals can be
excluded from the treated areas after application and until the material is no
longer visible.
metaldehyde products must be kept out of the reach of domestic animals and
children.
dogs have been known to ingest metaldehyde after opening or tearing packaging,
and that resulting exposures can be fatal
These statements must be accompanied by a graphic that depicts the prohibition
for allowing children and domestic animals access to treated areas (e.g., the words
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"Children and Pets" within a red circle with a red bar running diagonally through the
circle). Labels of residential use metaldehyde products already bear graphic images of
this nature that instruct the user as to how pellets should be placed (stylized plants with
granules distributed improperly are shown within a red circle with a diagonal red bar).
The formulators of metaldehyde have commented that they believe a "Children and Pets"
graphic of this nature could be misleading to consumers. The Agency is evaluating
precedents for this type of graphic in other consumer products, and is specifically seeking
public input in the comment period after the RED becomes available on how the
directions to exclude children and domestic animals from treated areas may be enhanced
via product labeling.
In addition, labels for all residential-use products:
must prominently display directions for users in the case of domestic animal
exposures, providing the information hotline number and instructing users or pet
owners to contact their veterinarians as soon as possible after exposure occurs.
must note that broadcast and foliar applications are prohibited.
must note that applications to turf and dichondra are prohibited.
will allow application only to non-turf areas directly surrounding plants (on soil or
mulch) listed on product labels.
will allow use only as a barrier around gardens or individual plants, with
application prohibited within one foot of vegetable plants or fruit-bearing plants
for which metaldehyde use is not allowed.
will allow application for ornamentals, and garden vegetable and fruit-bearing
plants only as a barrier treatment. The only allowable home garden use sites for
metaldehyde are ornamentals, cole crops and other leafy greens (cabbage,
broccoli, Brussels sprouts, cauliflower, kale, collard greens, etc.), lettuce, tomato,
citrus, strawberry, blueberries, and caneberries (e.g., raspberries, blackberries)
and other berries.
must be amended to provide application directions in user-friendly terms, for
example, "Apply pellets as a barrier around plants by distributing pellets evenly in
a line at a rate of X tablespoons per X linear foot." The application rates
described in this way must not represent use at an application rate greater than the
1.0 Ib ai/A/application for ornamentals. Applications for ornamentals are limited
to 6/year, at an interval not less than 21 days between applications. Application
rates and other application parameters for other uses are as described below.
The technical registrant of metaldehyde, Lonza, has committed to expediting
submission of residential-use products revised to reflect these requirements.
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The following formulation requirements must be implemented for residential-use
products containing metaldehyde:
Formulation of metaldehyde in combination with carbaryl is prohibited unless the
product is formulated to provide a single application rate that does not exceed the
maximum allowable rate for either active ingredient.
All residential use products containing metaldehyde must be formulated with
denatonium benzoate, or another bittering agent approved by the Agency, at
sufficient concentration to deter ingestion by domestic animals. The bittering
agent will also serve as a deterrent for ingestion by children.
In addition, labels for metaldehyde-carbaryl combination products must bear
language advising users that such products must not be applied unless both snails or slugs
and target pests for carbaryl are present. Since metaldehyde products will no longer be
permitted on turf, the utility of these combination products may be limited in the future.
Furthermore, the registrants are required to submit data demonstrating the
effectiveness of the bittering agent incorporated into the residential-use metaldehyde
products, at the concentration used in those formulations. Lonza has indicated that it is
evaluating a new agent, which is composed of the original bittering agent, denatonium
benzoate, plus an olfactory agent. The Agency is requiring palatability data for
denatonium benzoate and any new bittering agent the registrants wish to employ, to
confirm the effectiveness of such an approach in deterring ingestion by domestic animals.
If the data indicate that the aversion agent used in metaldehyde formulations (at the
concentration used in those formulations) is not efficacious in deterring ingestion by
domestic animals, the Agency may require additional testing and implementation of
additional mitigation measures.
The registrants are also required to implement a common reporting system for
domestic animal poisoning incidents associated with all metaldehyde products, and are
required to submit quarterly reports on incidents reported for the time period. The
registrants are required to submit a protocol for the reporting program to EPA for review
prior to implementing the program. The Agency's analysis of trends in the numbers and
severity of poisoning incidents associated with metaldehyde, or other relevant
information, will be the basis of decisions on additional requirements for risk mitigation.
The registrants are also required to submit data on the efficacy of metaldehyde
products formulated with non-food-based inerts and bulking agents. If the Agency finds
that products formulated with these materials are efficacious in controlling the target
pests, the registrants will be required to reformulate accordingly.
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7. Environmental
The Agency has assessed risks to nontarget wildlife associated with the residential
and agricultural uses of metaldehyde.
Based on a screening level assessment, the Agency has concluded that acute RQs
for birds and mammals exceed LOCs for acute risk and acute endangered species risk for
all uses of metaldehyde for most size ranges of animals. Incident data for domestic
animals and wildlife are supportive of the potential for risks of concern in mammalian
wildlife. Metaldehyde itself, and the food-based materials the pesticide is formulated
with, are reported to be attractive to animals. In contrast to the conservative nature of the
Agency's screening level exposure assessment, preferential selection of metaldehyde
granules as a food source would suggest that risks to non-target wildlife may be
underestimated.
Metaldehyde is slightly toxic to freshwater fish on an acute basis. RQs for
freshwater fish do not exceed LOCs as assessed. Testing of a representative freshwater
invertebrate did not result in mortality even at the highest dose tested. There are
significant data gaps for chronic toxicity to freshwater animals and for acute and chronic
toxicity to estuarine/marine animals. There are no data to allow an assessment of the
risks metaldehyde use poses to non-target aquatic mollusks, but because the pesticide is
an effective molluscicide, it is reasonable to assume that there may be risks associated
with exposures to non-target aquatic mollusks.
The Agency is specifying a number of risk mitigation measures to target risks to
wildlife. Required label language is detailed in Table 16.
Labels must allow use only on the following sites (maximum application
rate/application, maximum number of applications/season, minimum retreatment
interval):
Citrus: 1.0 Ib ai/A, 6 applications, 14 days
Cole crops and other leafy greens: 1.0 Ib ai/A, 3 applications, 14 days
Lettuce: 1.0 Ib ai/A, 3 applications, 14 days
Tomato: 1.0 Ib ai/A, 3 applications, 14 days
Strawberry (when grown as perennials only): 1.0 Ib ai/A, 3 applications, 14 days
Blueberries: 0.8 Ib ai/A, 2 applications, 14 days
Caneberries and other berries: 0.8 Ib ai/A, 3 applications, 14 days
Grass grown for seed: 0.8 Ib ai/A, 4 applications, 21 days
Artichokes (when grown as perennials): 1.0 Ib ai/A, 6 applications, 18 days
Artichokes (when grown as annuals): 1.0 Ib ai/A, 2 applications, 18 days
Ornamentals: 1.0 Ib ai/A, 6 applications, 21 days
Applications to turf and dichondra are prohibited. The mandated application rate
for ornamentals is lower than the rate assessed for this RED (3.5 Ibs ai vs. 1 Ib ai), as it is
for grass grown as seed (1.6 Ibs ai vs. 0.8 Ib ai). Numbers of applications are reduced
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relative to what was assessed in the RED for lettuce, cole crops and other leafy greens,
tomato, strawberries grown as perennials, caneberries and other berries, artichokes, and
ornamentals. Reductions in maximum application rates and numbers of repeat
applications reduce opportunities for exposure to domestic animals and wildlife, and
promote the use of alternate methods of slug and snail control. Retreatment intervals are
as proposed by Lonza and assessed by the Agency, and have not changed as a result of
the risk assessments.
For strawberries grown as annuals, pest populations are expected to be much
lower than in strawberries grown as perennials. The use of metaldehyde on
annual strawberries must be deleted from product labels. The Agency is soliciting
public comment on this prohibition of use on strawberries grown as annuals, will
consider any documentary evidence of grower need for metaldehyde on this crop.
Certain cultural practices may reduce damage from snails and slugs, and may
make metaldehyde applications more effective. Labels of residential use products
must provide summary information about cultural controls (e.g., remove leaf litter
and debris; during daylight hours, look for and remove slugs and snails in leaf
litter, mulch, or other protected areas adjacent to plants they feed on; water or
irrigate in the morning, when possible).
It should be noted that the Agency believes that a bittering agent likely would not
be effective in preventing ingestion of metaldehyde by terrestrial wildlife species because
of the great diversity of potentially exposed species and differences in how they perceive
taste. The Agency believes that these mitigation measures discussed in this section will
reduce potential environmental exposures to metaldeyhyde, for both aquatic and
terrestrial organisms. The Agency is requiring additional ecotoxicity data to reduce the
uncertainty in the ecological risk assessment.
8. Other Measures Addressing Both Domestic Animal and
Ecological Risks
Based on the similarity in size of some pet foods/wildlife forage items and the
larger pellet sizes of metaldehyde, and evidence suggesting that animals may mistake the
pellets for food, the formulators of metaldehyde products will be prohibited from
formulating granular materials at a rate of fewer than 35 pellets per gram.
Based on evidence that brightly colored granules may be less attractive to
animals, formulators must incorporate a coloring agent into their granular formulations.
Many metaldehyde products already are formulated with a blue color. It has been
suggested that the blue color may attract children who could mistake the pellets for
candy. Empirical or other evidence relating to the potential for reducing animal
exposures with the colored pellets is limited. In addition, the formulators of metaldehyde
have indicated that the use of colored pellets could affect the marketability of some kinds
of produce if the blue color splashes or bleeds onto plant parts, while other sources have
indicated that color transfer is not and should not be a problem for soil-applied baits. The
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Agency is specifically seeking public input on this issue in the comment period after the
RED becomes available.
The Agency believes that the risk mitigation measures required by the RED will
be effective in reducing risks below levels of concern. The Agency is requiring certain
confirmatory data to support the adequacy of those measures, and may require additional
mitigation measures and testing.
The registrants are required to submit data on the efficacy of metaldehyde
products formulated with non-food-based inerts and bulking agents. If the Agency finds
that products formulated with these materials are efficacious in controlling the target
pests, the registrants will be required to reformulate accordingly.
B.
Tolerance Considerations
The Agency has reassessed the one existing tolerance for metaldehyde, and found
a reasonable certainty of no harm to the U.S. population and all population subgroups
from the use of metaldehyde. The Agency also has identified new tolerances that are
needed for metaldehyde. The existing tolerance is a tolerance exemption of 0 ppm on
strawberry. Both the tolerance exemption and the lack of other tolerances for
metaldehyde are attributable to past belief by the Agency that residues of metaldehyde
would not be taken up by plants. The tolerance reassessment and tolerances needed to
support uses of metaldehyde are shown in Table 14.
Table 14. Tolerance Summary for Metaldehyde
Commodity
Current Tolerance (ppm)
Tolerance Reassessment (ppm)
Tolerance Listed Under 40 CFR §180.523(a)
Strawberry
0
6.25
Tolerances Needed under 40 CFR 180.523(a)
Artichoke, globe
Berry, group 13
Fruit, citrus, group 10
Prickly pear cactus
Vegetable, brassica,
leafy, group 5 (cole
crops)
Lettuce
Vegetable, fruiting,
group 8 (Tomato)
None
None
None
None
None
None
None
0.0625
0.15
0.26
0.0625
2.5
1.73
0.24
The use of metaldehyde on grass grown for seed necessitates development of
residue data and establishment of a tolerance for metaldehyde, because screenings from
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seed cleaning and grass hay from the treated fields may be used as animal feed. These
data, in development by IR-4, are expected to be submitted to the Agency in the future, at
which time the appropriate tolerance level can be identified.
C. Eligibility Decision
Metaldehyde products are currently labeled for many uses which are not being
supported by the technical registrant. Only those uses that are supported by the registrant
through development of required data have been assessed for this reregistration decision.
The uses of metaldehyde that are being supported are: turf/dichondra, ornamentals, citrus,
lettuce, cole crops and other leafy greens, tomato, strawberry, berries (including
blackberry, blueberry, currant, elderberry, gooseberry, raspberries), and grass grown for
seed, and artichoke. With the exception of the use on turf and dichondra, these uses of
metaldehyde are eligible for reregistration, provided that the risk mitigation measures
required by this RED are implemented, and the data submitted pursuant to the
requirements identified in this RED are confirmatory.
The IR-4 program of the U.S. Department of Agriculture, which develops residue
data for minor and specialty crops, has done research on a number of additional uses for
metaldehyde. At the current time, residue data for the use of metaldehyde on prickly pear
cactus and watercress are in development. While these uses were included in the health
effects and environmental risk assessments for metaldehyde, decisions on their
registration have not been made for this RED.
V. What Registrants Need to Do
A. Submissions for Technical-Grade Active Ingredient Products
1. Within 90 Days of Receipt of the Generic DCI
For each metaldehyde technical grade active ingredient product, the registrant
needs to submit the following items within 90 days of receiving the Generic DCI:
completed response forms to the generic DCI (i.e., DCI response form and
requirements status and registrant's response form); and
submit any time extension and/or waiver requests with a full written justification
2. Within Other Generic DCI Deadlines
Within the time limit specified in the generic DCI, the registrant must cite any
existing generic data or submit new generic data in response to the DCI. Please contact
Jill Bloom at (703) 308-8019 with questions regarding generic reregistration.
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By US mail: By express or courier service:
Document Processing Desk Document Processing Desk (DCI/SRRD)
(DCI/SRRD) Jill Bloom
Jill Bloom Office of Pesticide Programs (7508P)
US EPA (7508P) 4th Floor, One Potomac Yard
1200 Pennsylvania Ave., NW. 2777 S. Crystal Dr.
Washington, DC 20460 Arlington, VA 22202
B. Submissions for End-Use Products Containing Metaldehyde
1. Within 90 Days
Within 90 days from the receipt of the product-specific data call-in (PDCI), the
registrant must submit, for each product:
completed response forms to the PDCI (i.e., PDCI response form and
requirements status and registrant's response form); and
any time extension or waiver requests with a full written justification.
2. Within Product DCI Deadlines
Within eight months from the receipt of the PDCI, the registrant must submit:
two copies of the confidential statement of formula (EPA Form 8570-4);
a completed original application for reregistration (EPA Form 8570-1). Indicate
on the form that it is an "application for reregistration";
five copies of the draft label incorporating all label amendments outlined in Table
47 of this document;
a completed form certifying compliance with data compensation requirements
(EPA Form 8570-34); and
if applicable, a completed form certifying compliance with cost share offer
requirements (EPA Form 8570-32); and
the product-specific data responding to the PDCI.
Please contact Bonnie Adler at (703) 308-8523 with questions regarding product
reregistration and/or the PDCI. All materials submitted in response to the PDCI should
be addressed as follows:
By US mail: By express or courier service:
Document Processing Desk Document Processing Desk (PDCI/PRB)
(PDCI/PRB) Bonnie Adler
Bonnie Adler OPP (7508P)
US EPA (7508P) 4th Floor, One Potomac Yard
1200 Pennsylvania Ave., NW. 2777 S. Crystal Drive.
Washington, DC 20460 Arlington, VA 22202
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C. Manufacturing-Use ProductsData Requirements
The Agency has determined that additional generic data are needed to confirm
this reregistration eligibility decision. These data are summarized in Table 15, and cited
in the Generic DCI for metaldehyde.
Table 15. Generic Data Requirements for Metaldehyde
Guideline or Special Study Name or Description
Developmental neurotoxicity study (rat)
90 day inhalation toxicity study (rat)1
Mutagenicity battery
Field trials2
Reference standard for metaldehyde
Field accumulation in rotational crop
Turf dissipation study (TTR)
Aerobic Soil Metabolism5
Anaerobic Aquatic Metabolism
Aerobic Aquatic Metabolism
Terrestrial Field Dissipation6
Bivalve Acute (Embryo Larval) ECso
Estuarine/Marine Fish LCso
Estuarine/Marine Mollusk Shell Deposition ECso
Estuarine/Marine Mysid Shrimp ECso
Freshwater Fish Early Life-Stage
Daphnid Chronic Life-Cycle
Estuarine/Marine Invertebrate Life-Cycle
Freshwater Fish Full Life-Cycle
Seedling Emergence (Tier I)
OPPTS Guideline No.
870.6300
870.3465
870.5000 series
860.1500
860.1650
860.1900
875.2100
835.4100
835.4400
835.4300
835.6100
850.1055
850.1075
850.1025
850.1035
850.1400
850.1300
850.1350
850.1500
850.4100
1 The Agency will consider registrant submission of a waiver request for this data requirement supported by
discussion of the volatility of metaldehyde and potential for occupational inhalation exposure, or other
supporting information.
2 Confirmatory field trial data are required on leafy lettuce (2 tests) to support permanent tolerances on the
leafy vegetable crop group
3 Reference Standard must be submitted to the National Pesticide Standards Repository
4 Confirmatory data required to support intermediate-term exposure estimates
5 Weight-of-evidence of laboratory and field data suggests that there is uncertainty with relying on a single
aerobic soil metabolism test system. The submission of additional aerobic soil metabolism data is required
in order to minimize this uncertainty.
6 Soil samples were not tested at lower depths for metaldehyde. Study design must allow the Agency to
distinguish between metaldehyde residues in upper soil layer and undissolved pellets.
7 Requirement reserved pending review of related data
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Guideline or Special Study Name or Description
Vegetative Vigor (Tier I)
Aquatic Plant Toxicity (Tier I)
Incident reporting program
Palatability of materials incorporating bittering agent8
Efficacy of products utilizing non-food based inerts
OPPTS Guideline No.
850.4150
850.4400
NA
NA
NA
D. Labeling
To ensure compliance with FIFRA, manufacturing-use product (MUP) labeling
should be revised to comply with all current EPA regulations, PR Notices, and applicable
policies. Furthermore, all MUP labels must be amended to incorporate the risk
mitigation measures outlined in this RED. Table 16 details how language on the labels
must be amended. MUP labeling revised in this manner must be submitted within 90
days of receipt of the generic DCI issued pursuant to this RED.
In order to be eligible for reregistration, labeling for all end-use products
containing metaldehyde must be amended to incorporate the risk mitigation measures
outlined in this RED. Table 16 details how language on the labels must be amended.
End-use product labeling revised in this manner must be submitted within eight months
from the receipt of the PDCI issued pursuant to this RED
' Protocols required in advance of study initiation
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Table 47. Labeling Changes for Products Containing Metaldehyde
Description
Amended Labeling Language
Placement on Label
Manufacturing-Use Products
For all Manufacturing- Use
Products
"This product may be formulated into a molluscicide for the following use(s)
only: artichokes, blueberries, caneberries (bingleberry, black raspberry,
blackberry, boysenberry, dewberry, lowberry, marionberry, olallieberry, red
raspberry, youngberry) and other berries (currant, elderberry, gooseberry,
huckleberry, loganberry, lingonberry, juneberry, salal), citrus, lettuce, cole
crops and other leafy greens (broccoli, Brussels sprouts, cabbage, cauliflower,
cavalo, broccolo, collards, kale, kohlrabi, mizuna, mustard greens, spinach,
rape greens), grass grown for seed, ornamentals, tomato, and strawberry (grown
as perennials only)."
"This product may not be formulated into end-use products for use on turf
(except grass grown for seed), dichondra lawns, or strawberries grown as
annuals."
"This product may not be formulated into end-use granular or pelletized
products unless those products are formulated to incorporate a bright blue
coloring agent."
"This product may not be formulated into end-use granular or pelletized
products unless those products are formulated to contain more than 35 pellets
per gram."
"This product may not be formulated into end-use granular or pelletized
products with directions permitting use at residential sites (i.e., in yards or
gardens, around homes, apartments, schools, athletic fields, playgrounds, parks,
etc.) unless such products contain denatonium benzoate at 300 ppm or another
Directions for Use
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Description
Amended Labeling Language
Placement on Label
bittering agent approved by the Agency. The bittering agent must be of
sufficient concentration to deter ingestion by children and domestic animals."
"This product may not be formulated into end-use products with directions
permitting use at residential sites (i.e., in yards or gardens, around homes,
apartments, schools, daycare facilities, athletic fields, playgrounds, parks,
recreation areas, etc.) unless the labels of such products contain a graphic that
depicts the prohibition on allowing children and domestic animals access to
treated areas and specific warnings designed to reduce the numbers of incidents
involving children and domestic animals."
One of these statements may
be added to a label to allow
reformulation of the product
for a specific use or all
additional uses supported by a
formulator or user group
"This product may be used to formulate products for specific use(s) not listed
on the MP label if the formulator, user group, or grower has complied with U.S.
EPA submission requirements regarding support of such use(s)."
"This product may be used to formulate products for any additional use(s) not
listed on the MP label if the formulator, user group, or grower has complied
with U.S. EPA submission requirements regarding support of such use(s)."
Directions for Use
Environmental Hazards
Statements Required by the
RED and Agency Label
Policies
"Do not discharge effluent containing this product into lakes, streams, ponds,
estuaries, oceans, or other waters unless in accordance with the requirements of
a National Pollution Discharge Elimination System (NPDES) permit and the
permitting authority has been notified in writing prior to discharge. Do not
discharge effluent containing this product to sewer systems without previously
notifying the local sewage treatment plant authority. For guidance contact your
State Water Board or Regional Office of the EPA."
Precautionary
Statements
End Use Products Intended for Agricultural Use
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Description
Amended Labeling Language
Placement on Label
Domestic Animal
Precautionary Statements
"This product can be fatal to children and dogs (and other domestic animals)
when ingested. Children and dogs may be attracted to the product. Application
of this product is prohibited unless children and domestic animals can be
excluded from the treated area from the start of the application until applied
material is no longer visible."
Precautionary
Statements: Hazards
to Humans and
Domestic Animals
PPE Requirements
Established by the RED9
"Mixers, loaders, applicators, and other handlers must wear:
long-sleeved shirts and long pants, and
shoes plus socks."
Immediately
following/ below
Precautionary
Statements: Hazards
to Humans and
Domestic Animals
User Safety Requirements
"Follow manufacturer's instructions for cleaning/maintaining PPE. If no such
instructions for washables exist, use detergent and hot water. Keep and wash
PPE separately from other laundry."
"Discard clothing and other absorbent materials that have been drenched or
heavily contaminated with this product's concentrate. Do not reuse them."
Precautionary
Statements: Hazards
to Humans and
Domestic Animals
immediately
following the PPE
requirements
9 PPE established on the basis of Acute Toxicity of the end-use product must be compared to the active ingredient PPE in this document. The more protective
PPE must be placed in the product labeling. For guidance on which PPE is considered more protective, see PR Notice 93-7.
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Description
Amended Labeling Language
Placement on Label
User Safety
Recommendations
"User Safety Recommendations"
"Users should wash hands before eating, drinking, chewing gum, using
tobacco, or using the toilet."
"Users should remove clothing/PPE immediately if pesticide gets inside. Then
wash thoroughly and put on clean clothing."
"Users should remove PPE immediately after handling this product.
Wash the outside of gloves before removing. As soon as possible, wash
thoroughly and change into clean clothing."
Precautionary
Statements: Hazards
to Humans and
Domestic Animals
immediately
following
Engineering Controls
(Must be placed in a
box.)
Environmental Hazard
Statement
"This pesticide is toxic to fish and aquatic invertebrates. Do not apply directly
to water, to areas where surface water is present, or to intertidal areas below the
mean high water mark except as noted on appropriate labels. Drift and runoff
may be hazardous to aquatic organisms in water adjacent to treated areas. Do
not contaminate water when disposing of equipment wash waters or rinsate.
This pesticide is toxic to birds and mammals. Granules on soil surface may be
hazardous to terrestrial wildlife. Cover or collect any such materials spilled
during loading."
Precautionary
Statements
immediately
following the User
Safety
Recommendations
Poisoning Hotline
"Seek medical care as soon as possible after exposure. Have the product
container or label with you when you call a poison control center or doctor or
when going for treatment. For information on this pesticide product (including
health concerns, medical emergencies, or pesticide incidents), call the National
Pesticide Information Center at 1-800-858-7378.
"For incidents involving animals, seek veterinary care as soon as possible after
exposure. Have the product container or label with you when you call a poison
Precautionary
Statements, under
"First Aid" :
Poisoning Hotline
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Description
Amended Labeling Language
Placement on Label
control center or veterinarian or when taking an exposed animal for treatment.
For treatment advice and other information about exposures of animals to this
pesticide, call [registrant enters name of reporting service} at [registrant enters
appropriate toll-free telephone number}.
Restricted-Entry Interval for
products with directions for
use within scope of the
Worker Protection Standard
for Agricultural Pesticides
(WPS)
"Do not enter or allow worker entry into treated areas during the restricted
entry interval (REI) of 12 hours. Exception: if the product is soil-injected or
soil-incorporated, the Worker Protection Standard, under certain circumstances,
allows workers to enter the treated areas without restriction if there will be no
contact with anything that has been treated."
Directions for Use,
Under Agricultural
Use Requirements
Box
Early Entry Personal
Protective Equipment for
products with directions for
use within the scope of the
WPS
"PPE required for early entry to treated areas that is permitted under the
Worker Protection Standard and that involves contact with anything that has
been treated, such as plants, soil, or water, is:
* coveralls,
* shoes plus socks
* chemical-resistant gloves made of any waterproof material"
Direction for Use
Agricultural Use
Requirements box
General Application
Restrictions
"Do not apply this product in a way that will contact workers or other persons,
either directly or through drift. Only protected handlers may be in the area
during application. "
Direction for Use
Immediately above
the Agricultural Use
Requirements box
Other Application
Restrictions
"This product is intended solely for use on agricultural crops grown for
commercial or research purposes. This product may not be applied to
residential sites (i.e., in yards or gardens, around homes, apartments, schools,
athletic fields, playgrounds, parks, etc.)."
"Broadcast or foliar applications of this product are prohibited."
Directions for Use
Crop Specific Directions for
End-use product labels must be amended to contain directions for use only on
Directions for Use
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Description
Amended Labeling Language
Placement on Label
Use
the following crop- and use-sites and only with the maximum application rate,
maximum number of applications per growing season, and minimum
retreatment intervals as listed below. All other crop- and use-sites must be
removed from end-use product labels.
Artichokes:
When grown as a perennial, the maximum application rate is 1.0 Ib ai/A
per application. A maximum of 6 applications are permitted per growing
season at a minimum of retreatment interval of 18 days.
- When grown as an annual, the maximum application rate is 1.0 Ib ai/A per
application. A maximum of 2 applications are permitted per growing
season at a minimum of retreatment interval of 18 days.
Blueberries: the maximum application rate is 0.8 Ib ai/A per application. A
maximum of 2 applications are permitted per growing season at a minimum of
retreatment interval of 14 days.
Caneberries (bingleberry, black raspberry, blackberry, boysenberry, dewberry,
lowberry, marionberry, olallieberry, red raspberry, youngberry) and Other
Berries (currant, elderberry, gooseberry, huckleberry, loganberry, lingonberry,
juneberry, salal): the maximum application rate is 0.8 Ib ai/A per application.
A maximum of 3 applications are permitted per growing season at a minimum
of retreatment interval of 14 days.
Citrus: the maximum application rate is 1.0 Ib ai/A per application. A
maximum of 6 applications are permitted per growing season at a minimum of
retreatment interval of 14 days.
Lettuce, Cole Crops, And Other Leafy Greens: (broccoli, Brussels sprouts,
associated with the
specific crop- or use-
site
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Description
Storage Restrictions
Amended Labeling Language
cabbage, cauliflower, cavalo, broccolo, collards, kale, kohlrabi, mizuna,
mustard greens, spinach, rape greens): the maximum application rate is 1.0 Ib
ai/A per application. A maximum of 3 applications are permitted per growing
season at a minimum of retreatment interval of 14 days.
Grass grown for seed: the maximum application rate is 0.8 Ib ai/A per
application. A maximum of 4 applications are permitted per growing season at
a minimum of retreatment interval of 21 days. Applications to turfgrass (other
than grass grown for seed) are prohibited.
Ornamentals: the maximum application rate is 1.0 Ib ai/A per application. A
maximum of 6 applications are permitted per growing season at a minimum of
retreatment interval of 21 days.
Tomatoes: the maximum application rate is 1.0 Ib ai/A per application. A
maximum of 3 applications are permitted per growing season at a minimum of
retreatment interval of 14 days.
Strawberries (grown as perennials only): the maximum application rate is 1.0 Ib
ai/A per application. A maximum of 3 applications are permitted per growing
season at a minimum of retreatment interval of 14 days. Applications to
strawberries grown as annuals are prohibited.
"This product can be fatal to children and dogs (and other domestic animals) if
ingested. Dogs have been known to ingest metaldehyde after opening or
tearing packaging. Store this product in its original packaging, in a cool, secure
location, and out of reach of children and pets. Do not store in any location
where children and domestic animals can access the packaging or the product."
Placement on Label
Storage and Disposal
Products Intended for Use at Residential Sites
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Description
Amended Labeling Language
Placement on Label
Precautionary Statement and
Graphic Depiction for
Products Intended for Use at
Residential Sites
The label of any end-use product with directions for use at residential sites (i.e.,
in yards or gardens, around homes, apartments, schools, daycare facilities,
athletic fields, playgrounds, parks, recreation areas, etc.) must contain a graphic
that depicts the prohibition on allowing children and domestic animals access
to treated areas. For example, the symbol may be a red circle with the words
"Children" and "Pets" within the circle and with a red bar running diagonally
through it.
The following specific warning statements must be added to the label in close
association to the above graphic:
"Keep out of reach of children and domestic animals. This pesticide may be
fatal to children and dogs (and other domestic animals) when ingested.
Exclude children and pets from treated areas until the applied product is no
longer visible. For additional precautionary measures, see "Directions for Use"
and "Storage and Disposal."
Front panel
Precautionary Language
"IMPORTANT: This product may be fatal to children and dogs (and other
domestic animals) if ingested. Keep out of reach of children and domestic
animals. Children and dogs may be attracted to metaldehyde products, and
their packaging. Keep children and dogs (and other domestic animals) out of
treated areas from the start of application until the applied product is no longer
visible."
Precautionary
Statements: Hazards
to Humans and
Domestic Animals
Poisoning Hotline
"Seek medical care as soon as possible after exposure. Have the product
container or label with you when you call a poison control center or doctor or
when going for treatment. For information on this pesticide product (including
health concerns, medical emergencies, or pesticide incidents), call the National
Pesticide Information Center at 1-800-858-7378.
"For incidents involving animals, seek veterinary care as soon as possible after
Precautionary
Statements, under
"First Aid" :
Poisoning Hotline
Page 49 of 53
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Description
Amended Labeling Language
Placement on Label
exposure. Have the product container or label with you when you call a poison
control center or veterinarian or when taking an exposed animal for treatment.
For treatment advice and other information about exposures of animals to this
pesticide, call [registrant enters name of reporting service} at [registrant enters
appropriate toll-free telephone number}.
Environmental Hazard
Statement for Residential Use
Products
"This product is toxic to fish and aquatic invertebrates. Do not apply product
near water or storm drains. Do not apply if heavy rain is expected. Apply this
product only around gardens and ornamental plants.
For granular or pelletized product, add:
"This pesticide is toxic to birds and mammals. Sweep up or collect and remove
any product that lands on the driveway, sidewalk, or other hard surface on
which it is spilled."
Precautionary
Statements
General Application
Restrictions
"Do not apply this product in a way that will contact other persons or pets
either directly or through drift. Keep people and pets out of the area during
application."
Directions for Use
under General
Precautions and
Restrictions
Other Application
Restrictions
"This pesticide may be fatal to children, and dogs, and other domestic animals
if ingested. Dogs and other domestic animals are attracted to metaldehyde
products, both in the package and when applied. Children may also be
attracted to these products. Children and dogs (and other domestic animals)
must be kept out of treated areas from the start of application until the applied
product is no longer visible."
"Application of this metaldehyde product is prohibited unless children and dogs
(and other domestic animals) can be excluded from the treated areas from the
start of application until the applied product is no longer visible."
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Description
Amended Labeling Language
Placement on Label
"Applications to turf and dichondra are prohibited. Application is permitted
only to non-turf areas (i.e., on soil or mulch) directly surrounding plants listed
for use on the label."
"Broadcast and foliar applications of this product are prohibited. Application is
permitted only as a barrier around gardens or individual plants. Application is
prohibited within one foot of vegetable plants or fruit-bearing plants not listed
on this label."
"Certain cultural practices may reduce damage from snails and slugs, and may
make metaldehyde applications more effective. Examples of cultural methods
to reduce snail and slug populations include:
removing leaf litter and debris to eliminate places for slugs and snails to hide
during the day;
looking for and removing slugs and snails during daylight hours in leaf litter,
mulch, or other protected areas adjacent to plants they feed on;
watering in the morning rather than the evening to reduce humidity during
the night when snails and slugs are active."
Crop- and Use-Site Specific
Directions for Use
NOTE: Application rates
must be provided in user-
friendly terms, for example,
"Apply pellets as a barrier
around plants by distributing
pellets evenly in a line at a
rate of X tablespoons per X
linear foot."
End-use product labels must be amended to contain directions for use only on
the following crop- and use-sites and only with the maximum application rate,
maximum number of applications per growing season, and minimum
retreatment intervals as listed below. All other crop- and use-sites must be
removed from end-use product labels.
Artichokes:
- When grown as a perennial, the maximum application rate is 1.0 Ib ai/A
per application. A maximum of 6 applications are permitted per growing
season at a minimum of retreatment interval of 18 days.
When grown as an annual, the maximum application rate is 1.0 Ib ai/A per
Directions for Use
associated with the
specific crop- or use-
site
Page 51 of 53
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Description
Amended Labeling Language
Placement on Label
application. A maximum of 2 applications are permitted per growing
season at a minimum of retreatment interval of 18 days.
Blueberries: the maximum application rate is 0.8 Ib ai/A per application. A
maximum of 2 applications are permitted per growing season at a minimum of
retreatment interval of 14 days.
Caneberries (bingleberry, black raspberry, blackberry, boysenberry, dewberry,
lowberry, marionberry, olallieberry, red raspberry, youngberry) and Other
Berries (currant, elderberry, gooseberry, huckleberry, loganberry, lingonberry,
juneberry, salal): the maximum application rate is 0.8 Ib ai/A per application.
A maximum of 3 applications are permitted per growing season at a minimum
of retreatment interval of 14 days.
Citrus: the maximum application rate is 1.0 Ib ai/A per application. A
maximum of 6 applications are permitted per growing season at a minimum of
retreatment interval of 14 days.
Lettuce, Cole Crops, And Other Leafy Greens (broccoli, Brussels sprouts,
cabbage, cauliflower, cavalo, broccolo, collards, kale, kohlrabi, mizuna,
mustard greens, spinach, rape greens): the maximum application rate is 1.0 Ib
ai/A per application. A maximum of 3 applications are permitted per growing
season at a minimum of retreatment interval of 14 days.
Ornamentals: the maximum application rate is 1.0 Ib ai/A per application. A
maximum of 6 applications are permitted per growing season at a minimum of
retreatment interval of 21 days.
Tomatoes: the maximum application rate is 1.0 Ib ai/A per application. A
Page 52 of 5 3
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Description
Amended Labeling Language
Placement on Label
maximum of 3 applications are permitted per growing season at a minimum of
retreatment interval of 14 days.
Strawberries (grown as perennials only) the maximum application rate is 1.0 Ib
ai/A per application. A maximum of 3 applications are permitted per growing
season at a minimum of retreatment interval of 14 days. Applications to
strawberries grown as annuals are prohibited.
Storage Restrictions
"This product can be fatal to children and dogs (and other domestic animals) if
ingested. Dogs have been known to ingest metaldehyde after opening or
tearing packaging. Store this product in its original packaging, in a cool, secure
location, and out of reach of children and pets. Do not store in any location
where children or domestic animals can access the packaging or the product."
Storage and Disposal
Page 53 of 53
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