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

Summary information for carbaryl, carbofuran, methomyl, 1-napthol, and 3-hydroxycarbofuran
based on the recent studies (2003-2007) conducted by Washington Departments of Agriculture
and Ecology are presented below (Table 57). All sampling was done in streams that contain
listed Pacific salmonids. These data are a subset of the data listed in Table 56. Sampling
intensity was approximately the same for the three parent compounds considered in this Opinion
(~1,200 samples each), with slightly fewer sampling events for the degradates. Based on the
method of reporting in the database, we cannot determine how many samples may have
contained detection of any of the compounds that were below LOQs. Carbaryl appeared most
often in the samples (4.3%), followed by 1-napthol (1.0%), and methomyl (0.7%). Carbofuran
and 3-hydroxycarbofuran appeared less often (0.2% and 0.2% respectively). Quantifiable
concentrations ranged from 0.01 – 10.0 μg/L for carbaryl, 0.028 – 0.16 μg/L for carbofuran,
0.015 – 0.17 μg/L for methomyl, 0.01 – 0.641 for 1-napthol, and 0.095 – 0.15 μg/L for 3-
hydroxycarbofuran.
Table 57. Summary of Occurrences of Carbofuran, Carbaryl, Methomyl, 1-Napthol and 3-
Hydroxycarbofuran in recent studies by Washington Department of Ecology (2003-2007)
Statistic Carbaryl Carbofuran Methomyl 1-Napthol
3-Hydroxy
carbofuran
Samples in data set 1,223 1,208 1,207 1,003 102
Quantifiable samples 52 3 9 10 2
% of quantifications in data set 4.3% 0.2% 0.7% 1.0% 0.2%
LOQ range (μg/L) 0.01-0.25 0.01-0.25 0.01-0.25 0.03-0.25 0.02-0.25
Minimum concentration (μg/L) 0.0100 0.0280 0.015 0.01 0.0950
Maximum concentration (μg/L) 10.0 0.16 0.17 0.641 0.15
Arithmetic mean concentration
(μg/L)
0.30 0.09 0.043 0.1338 0.12
Standard deviation (μg/L) 1.40 0.07 0.050 0.189 0.04
Median concentration 0.03 0.08 0.019 0.078 0.12
Three studies in the EIM database reported sediment concentrations. One was conducted to
determine the concentrations of carbaryl and 1-napthol in the sediment of Willapa Bay, and two
were sediment toxicity assessments. The sediment toxicity assessments, which provided the
reported values (Table 58) for carbofuran, methomyl, and 3-hydoxycarbofuran as well as some
data on carbaryl and 1-napthol, had an LOQ of 100 μg/kg. The LOQs for the Willapa Bay
analysis were lower, ranging from 22-37 μg/kg. Neither of the sediment toxicity studies reported
detectable concentration of any of the chemicals. In the Willapa Bay study, both carbaryl (range
29-3,400 μg/kg) and 1-napthol (range 34-280 μg/kg) were detected. These data represent a very
297