# Final National Recommended Ambient Water Quality

Criteria for Carbaryl

- 201 2

S u m m a r y

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 ( Sevin ® ) is a pesticide used to control insects, slugs a nd snails and to thin fruit in
orchards. It can enter water bodies through
runoff an d potentially pose risk s to aquatic life

. Carbaryl is the second most frequently found insecticide in water, with detections in approximately half of monitored urban streams.

Th e 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 acu te 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 t ime, there are insufficient data to
calculate a chronic AWQC for estuarine and marine organisms.

W h a t a r e a q u a t i c l i f

e c r i t e r i a ?
Aquatic life ambient water quality criteria are numeric values that protect aquatic life from the
harmful effects of pollutants in surface water s

. 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 scientif ic judgments about the relationship between pollutant concentrations and potential
environ mental and human health effects

.
EPA’s national recommended water quality criteria provide guidance to states, territories and authorized tribes in adopting water qu ality criteria that meet the requirements of the C lean
W ater A ct . They are not regulations themselves and do not impose legally binding requirements on EPA, states, territories, authorized tribes or the public.

W h a t i s c a r b a r

y l ?
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 v ia acetyl cholinesterase
inhibition. Carbaryl also affects plant development and is used to thin frui t in orchards. Carbaryl has many trade names, but is most commonly known as Sevin ®

. I t 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 Geologic al Survey National Water Quality Assessment Program reported carbaryl as the second most frequently
detected insecticide in water. It has been found in appro ximately 50 percent of monitored urban

streams. EPA previously deve loped national
recommended ambie nt 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 eligib le for reregistration in 2007. Carbaryl is currently undergoing registration review , which
is scheduled to be completed in 2016.

H o w w e r e t h e s e w a t e r q u a l i t y c r i t e r i a f o r

c a r b a r y l d e r i v e d ?
EPA derived these aquatic life water quality
criteria for carbaryl using EPA’s 1985 Guidelines f

or Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses

. The Office of Water EPA

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- F

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4304T May 201 2carbaryl criteria document has a new format that

follows EPA’s Guidelines for Ecological Risk
Assessment (EPA/630/R

- 95/002F). Toxicity data
fo r 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 t oxicity
data and other information on the effects of carbaryl to both internal and external peer
review

.

S p e c i f i c a l l y , w h a t a r e t h e f i n a l a q u a t i c l i f e

c r i t e r i a v a l u e s f o r c a r b a r

y l ?

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 μg/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,

e stuarine/marine aquatic animals would have an appropriate level of protection if the one

- hour average concentration does not exceed 1.6 μg/L
more than once e very 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
Acute Chronic
Freshwater 2.1 μg/L 2.1 μg/L
Estuarine/marine 1.6 μg/L N/A
N/A

– not available H o w t o V i e w t h e C r i t e r i a D o c u m e n t
EPA has established an official public docket for
this action under Docket ID No. EPA

- HQ

- OW

201 2

- 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

.

F o r M o r e I n f o r m a t i o n 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 Pennsylvan ia
Ave ., N.W., Washington, D.C. 20460.