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

and beans), and alachlor (used on beans and corn) were the most commonly detected
pesticides. These same compounds accounted for 75% of all detections. Seventeen
different pesticides were detected downstream from American Falls Reservoir. Carbaryl
and carbofuran were each detected in only 1% of samples; methomyl was screened for
but not detected (Clark, Maret et al. 1998).
Hood River Basin
The Hood River Basin ranks fourth in the state of Oregon in total agricultural pesticide
usage (Jenkins, Jepson et al. 2004). The land in Hood River basin is used to grow five
crops: alfalfa, apples, cherries, grapes, and pears. About 61 a.i.s, totaling 1.1 million lbs,
are applied annually to roughly 21,000 acres. Of the top nine, three are carbamates and
three are organophosphate insecticides (Table 40). These compounds will have a similar
mode of action, though different toxicities, as carbaryl, carbofuran, and methomyl.
Table 40. Amount of most common a.i.s applied to crops in Hood River Basin 1990-1996
(Jenkins et al. 2004).
Active Ingredient Class Lbs applied
Oil - 624,392
Lime Sulfur - 121,703
Mancozeb Carbamate 86,872
Sulfur - 60,552
Ziram Carbamate 45,965
Azinphos-methyl Organo-phosphate 22,294
Metam-Sodium Carbamate 17,114
Phosmet Organo-phosphate 15,919
Chlorpyrifos Organo-phosphate 14,833
The Hood River basin contains approximately 400 miles of perennial stream channel, of
which an estimated 100 miles is accessible to anadromous fish. These channels are
important rearing and spawning habitat for salmonids, making pesticide drift a major
concern for the area.
Central Columbia Plateau: NAWQA Assessment
The USGS sampled 31 surface-water sites representing agricultural land use, with
different crops, irrigation methods, and other agricultural practices for pesticides in Idaho
and Washington from 1992-1995 (Williamson, Munn et al. 1998). Pesticides were
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