Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

small subset of potentially contaminated sediments, and the negative results should not
necessarily be interpreted to mean that these chemicals are not in the sediment.
Table 58. Summary of Occurrences of Carbofuran, Carbaryl, Methomyl, 1-Napthol and 3-
Hydroxycarbofuran in Sediments in Washington EIM Database (1988-2007)
Statistic Carbaryl Carbofuran Methomyl 1-Napthol
3-Hydroxy
carbofuran
Samples in data set 26 26 26 69 26
Quantifiable samples 17 0 0 9 0
% of quantifications in data set 65.32% 0% 0% 13.0% 0%
LOQ range ( g/kg) 22-160 100 100 22-58 100
Minimum concentration ( g/kg)
Maximum concentration ( g/kg)
Arithmetic mean concentration
29
3,400
762
NA
NA
NA
NA
NA
NA
34
280
122
NA
NA
NA
( g/kg)
Standard deviation ( g/kg)
Median concentration ( g/kg)
1,166
200
NA
NA
NA
NA
75
120
NA
NA
Summary of National and State Monitoring Databases
Overall, data from the three sets of monitoring data examined by NMFS are relatively consistent,
with carbaryl generally being the most frequently quantifiable parent compound. No state
monitoring data were available from Oregon or Idaho. Carbaryl and carbofuran were measured
in concentrations ranging from 0.0001-33.5 μg/L. Methomyl generally was measured at slightly
lower concentrations, ranging from 0.004-5.4 μg/L. Both 1-napthol and 3-hydroxycarbofuran
were detected in slightly lower concentrations, ranging from 0.0007-0.64 μg/L, than any of the
parent compounds. Water concentrations based on these monitoring data, as anticipated, were
generally lower than those based on modeling estimates.
Targeted Monitoring Studies
Numerous studies have been conducted in coordination with applications of carbaryl in
Washington State to control burrowing shrimp in commercial oyster beds. Several investigators
have documented water column concentrations exceeding several mg/L, with a peak detection of
27,800 μg/L (27.8 mg/L) in one estuary. Those monitoring studies are discussed in greater detail
in the Risk Characterization portion of the Opinion.
The BEs for carbofuran (EPA 2004) and methomyl (EPA 2003) report some targeted studies
evaluating pesticide concentrations in field runoff and receiving water bodies. The carbofuran
BE reports concentrations of 16-28 μg/L of carbofuran in runoff from treated rice fields 26 d
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