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

sampling protocol specifies an attempt to avoid collection of excessive particulates (Johnson and
Cowles 2003). Whole water concentrations for compounds that sorb significantly to the
particulate phase will appear higher than those for a filtered sample, which represents only the
dissolved phase.
The procedure for reporting in the EIM database includes reporting non-detects as the reporting
limit for that particular sample, and adding a “U” data qualifier. The reporting limit was not
specified in the data accessed by NMFS, thus LOQ ranges (Table 56) were estimated based on
“U”-qualified data. Summary statistics were calculated on samples with values above the LOQ
(i.e., not qualified with a “U”).
Summary information for carbaryl, carbofuran, methomyl, 1-napthol, and 3-hydroxycarbofuran
based on all data in the database is reported below (Table 56). Sampling intensity was
approximately the same for the three parent compounds considered in this Opinion (~1,400
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
(8.5%), followed by carbofuran (4.0%), and methomyl (3.5%). The degradates were detected
slightly less often when they were analytes, with 1-napthol quantifiable in 1.8% of the samples,
and 3-hydroxycarbofuran quantifiable in 3.3%. Quantifiable concentrations ranged from 0.002 –
10.0 μg/L for carbaryl, 0.01 – 2.3 μg/L for carbofuran, 0.0150 – 0.17 μg/L for methomyl, 0.01-
0.64 for 1-napthol, and 0.05 – 0.42 μg/L for 3-hydroxycarbofuran.
Table 56. Summary of Occurrences of Carbofuran, Carbaryl, Methomyl, 1-Napthol and 3-
Hydroxycarbofuran in Surface Water - Washington EIM Database (1988-2007)
Statistic Carbaryl Carbofuran Methomyl 1-Napthol
3-Hydroxy
carbofuran
Samples in data set 1477 1410 1402 1173 1396
Quantifiable samples 126 57 49 23 46
% of quantifications in data set 8.5% 4.0% 3.5% 2.0% 3.3%
LOQ range (μg/L)
0.002-
25.0
0.01-25.0 0.01-5.0 0.01-5.0 0.01-10.0
Minimum concentration (μg/L) 0.01 0.028 0.02 0.01 0.10
Maximum concentration (μg/L) 10.0 0.16 0.17 0.64 0.15
Arithmetic mean concentration
(μg/L)
0.30 0.09 0.04 0.13 0.12
Standard deviation (μg/L) 1.40 0.07 0.05 0.19 0.04
Median concentration 0.03 0.08 0.02 0.08 0.12
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