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

monitored in California, Idaho, Oregon, and Washington. The database query resulted in
approximately 5,000 samples in which one or more of the compounds was an analyte
Approximately 350 unique sampling locations were represented. Available data covered a range
of 15 years, from 1992-2007. Land uses associated with the sampling stations included
agriculture, forest, rangeland, urban, and mixed use. Some stations occurred only once in the
data set, others appeared multiple times across a span of years. The frequency of detection is a
combination of the actual occurrence of pesticides in the water and the sampling intensity.
Values reported are for a filtered water sample (0.7 micron glass fiber filter), representing the
dissolved phase. Chemicals transported primarily in the particulate phase would be
underreported in this data set. No sediment or tissue data were available from USGS for these
compounds. Because the USGS monitoring program does not generally coordinate sampling
efforts with specific pesticide applications or runoff events, detected concentrations are likely to
be lower than actual peak concentrations that occur.
Summary information for quantifiable concentrations of carbaryl, carbofuran, methomyl, and 1napthol
is reported below (Table 54). Non-detects in this data set are reported as less than (“