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

factor in the degree of toxicity of carbofuran. At pHs above 9, carbofuran breaks down fairly
rapidly (half-life of 0.8-15 h) while at pH 7 reported half-lives range from 2- 28 d. Therefore,
pH is an important consideration when evaluating toxicity of carbofuran in the aquatic
environment. We discuss these effects and other considerations in more detail under the risk
hypotheses.
Figure 40. Carbofuran exposure concentrations and salmonid assessment endpoints’ effect
concentrations in µg/L
Methomyl
We expect a portion of fish to be exposed to upper end concentrations which would overlap with
most of the effect thresholds. (Figure 41). As with carbaryl and carbofuran, prey survival was
the most sensitive endpoint assessed. More sensitive prey, with EC50s at the lower end of the
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