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

deethylatrazine, carbaryl, diazinon, malathion, and DDE. In addition to current usechemicals
legacy chemicals continue to pose a serious problem to water quality and fish
communities despite their ban in the 1970s and 1980s (Hinck, Schmitt et al. 2004).
Fish and macroinvertebrate communities exhibit an almost linear decline in condition as
the level of agriculture intensity increases within a basin (Cuffney, Meador et al. 1997;
Fuhrer, Morace et al. 2004). A study conducted in the late 1990s examined 11 species of
fish, including anadromous and resident fish collected throughout the basin, for a suite of
132 contaminants. They included 51 semi-volatile chemicals, 26 pesticides, 18 metals, 7
PCBs, 20 dioxins, and 10 furans. Sampled fish tissues revealed PCBs, metals,
chlorinated dioxins and furans (products of wood pulp bleaching operations), and other
contaminants.
Yakima River Basin: NAWQA analysis
The Yakima River Basin is one of the most agriculturally productive areas in the U.S.
(Fuhrer, Morace et al. 2004). Croplands within the Yakima Basin account for about 16%
of the total basin area of which 77% is irrigated. The extensive irrigation-water delivery
and drainage system in the Yakima River Basin greatly controls water quality conditions
and aquatic health in agricultural streams, drains, and the Yakima River (Fuhrer, Morace
et al. 2004). From 1999 to 2000, the USGS conducted a NAWQA study in the Yakima
River Basin. Fuhrer et al. (2004) reported that nitrate and orthophosphate were the
dominant forms of nitrogen and phosphorus found in the Yakima River and its
agricultural tributaries. Arsenic, a known human carcinogen, was also detected in
agricultural drains at elevated concentrations during the nonirrigation season when
ground water is the primary source of streamflow.
The USGS also detected 76 pesticide compounds in the Yakima River Basin. They
include 38 herbicides (including metribuzin), 17 insecticides (such as carbaryl, diazinon,
and malathion), 15 breakdown products, and 6 others. Ninety-one percent of the samples
collected from the small agricultural watersheds contained at least two pesticides or
pesticide breakdown products. Carbaryl was detected in 29% of tributary samples and
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