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

Figure 41. Methomyl exposure concentrations and salmonid assessment endpoints’ effect
concentrations in µg/L
Relationship of pesticide use to effects in the field
Schulz (2004) reviewed 45 field and in situ studies published in peer-reviewed journals (from
1982-2003) that evaluated relationships between insecticide contamination and biological effects
in freshwater aquatic ecosystems and included invertebrates and fishes. For each study, the
authors classified the relationship of exposure to effect in one of four categories: no relation,
assumed relation, likely relation, and clear relation based on the cited authors’ judgment of their
own results. A relationship was classified as clear only if the exposure was quantified and the
effects were linked to exposure temporally and spatially. The review concluded that “about 15
of the 42 studies revealed a clear relationship between quantified, non-experimental exposure
and observed effects in situ, on abundance [aquatic invertebrate], drift, community structure, or
dynamics” (Schulz 2004). Although the top three insecticides most frequently detected at levels
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