x>EPA
United States
Environmental Protection
Agency
Office of Water   EPA - 820-F-12-004
                                                    4304T
                                                   May  2012
  Final National Recommended Ambient  Water Quality
                       Criteria for Carbaryl - 2012
Summary
EPA has published in the Federal Register final
national recommended ambient water quality
criteria (AWQC) for the protection of aquatic
life from the potential effects of carbaryl.
Carbaryl (SevinŽ) is a pesticide used to control
insects, slugs and snails and to thin fruit in
orchards.  It can enter water bodies through
runoff and potentially pose risks to aquatic life.
Carbaryl is the second most frequently found
insecticide in water, with detections in
approximately half of monitored urban streams.

The criteria document will help states,
territories, and authorized tribes add to their
water quality standards a concentration level for
carbaryl, at or below which aquatic organisms
will be protected. EPA's national recommended
final acute and chronic AWQC for protecting
freshwater organisms from potential effects of
carbaryl is 2.1 micrograms per liter. To protect
estuarine and marine organisms from potential
acute effects of carbaryl,  EPA is recommending
a final acute AWQC of 1.6 micrograms per liter.
At the present time, there are insufficient data to
calculate a chronic AWQC for estuarine and
marine organisms.

What are aquatic life criteria?
Aquatic life ambient water quality criteria are
numeric values that protect aquatic life from the
harmful effects of pollutants in surface waters.
Under section 304(a) of the Clean Water Act,
EPA is required to develop and publish criteria
for water quality that reflects the "latest
scientific knowledge." These water quality
criteria are based solely on data and scientific
judgments about the relationship between
pollutant concentrations and potential
environmental and human health effects.

EPA's national recommended water quality
                          criteria provide guidance to states, territories and
                          authorized tribes in adopting water quality
                          criteria that meet the requirements of the Clean
                          Water Act. They are not regulations themselves
                          and do not impose legally binding requirements
                          on EPA, states, territories, authorized tribes or
                          the public.

                          What is carbaryl?
                          Carbaryl is a member of the N-methyl carbamate
                          class of pesticides, which share a common
                          mechanism of toxicity by affecting the nervous
                          system in animals via acetyl cholinesterase
                          inhibition. Carbaryl also affects plant
                          development and is used to thin fruit in orchards.
                          Carbaryl has many trade names, but is most
                          commonly known as SevinŽ. It is registered in
                          the U.S. for controlling  insect pests on more
                          than 115 agricultural and other sites, including
                          home and garden uses.

                          In a 2006 report, the US Geological Survey
                          National Water Quality Assessment Program
                          reported carbaryl as the second most frequently
                          detected insecticide in water. It has been found
                          in approximately 50 percent of monitored urban
                          streams. EPA previously developed national
                          recommended ambient water quality criteria for
                          the other three most frequently detected
                          registered insecticides in U.S. waters
                          (chloropyrifos, diazinon and malathion).
                          Carbaryl was re-evaluated by EPA and found to
                          be eligible for reregistration in 2007. Carbaryl is
                          currently undergoing registration review, which
                          is scheduled to be completed in 2016.

                          How were these water quality criteria for
                          carbaryl derived?
                          EPA derived these aquatic life water quality
                          criteria for carbaryl using EPA's  1985
                          Guidelines for Deriving Numerical National
                          Water Quality Criteria for the Protection of
                          Aquatic Organisms and Their Uses. The

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carbaryl criteria document has a new format that
follows EPA's Guidelines for Ecological Risk
Assessment (EPA/630/R-95/002F). Toxicity data
for developing the water quality criteria were
obtained from peer-reviewed open literature
studies and from studies submitted to EPA for
the registration and reregistration of carbaryl.
To ensure the quality of the information, EPA's
Office of Water worked closely with the Office
of Pesticide Programs and subjected the toxicity
data and other information on the effects of
carbaryl to both internal and external peer
review.

Specifically, what are the final aquatic life
criteria values for carbaryl?
Based on available studies, EPA's national
recommended final acute and chronic ambient
water quality criteria for protecting freshwater
aquatic animals from the potential effects of
carbaryl is 2.1 micrograms per liter (Table 1).
This means that freshwater aquatic organisms
would have an appropriate level of protection if
the one-hour average concentration and the four-
day average concentration of carbaryl does not
exceed 2.1 (ig/L more than once every three
years  on average.

For the protection of estuarine and marine
organisms, EPA is recommending an acute
ambient water quality criterion of 1.6
micrograms per liter (Table 1). In this case,
estuarine/marine aquatic animals would have an
appropriate level of protection if the one-hour
average concentration does not exceed  1.6 (ig/L
more than once every three years on average
(except where a locally important species may
be more sensitive). At the present time, there
are insufficient data to calculate a chronic
estuarine and marine criterion.

Table 1. Summary of Aquatic Life Criteria for
Carbaryl
How to View the Criteria Document
EPA has established an official public docket for
this action under Docket ID No. EPA-HQ-OW-
2012-0787, accessed at www.regulations.gov.
You may also download the document from
http://water.epa.gov/scitech/swguidance/standar
ds/criteria/aqlife/index.cfm.
For More Information
Contact:  Diana Eignor by telephone at (202)
566-1143, or by email at eignor.diana@epa.gov.
or by mail at U.S. EPA, Health and Ecological
Criteria Division (4304T), 1200 Pennsylvania
Ave., N.W., Washington, D.C. 20460.

Freshwater
Estuarine/marine
Acute
2.1 Mg/L
1.6jig/L
Chronic
2.1 Mg/L
N/A
N/A - not available

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