Central to this study is to evaluate the toxicity of deltamethrin
and fenvalerate in soil by highlighting the differences in terms of
toxic sensitivity among the several endpoints. The results emphasized
that concentration, exposure time, endpoints selected and
environmental matrix, all influenced the identification of toxicity
response of deltamethrin and fenvalerate. Deltamethrin has
been classified as moderately toxic, and fenvalerate as highly toxic
in the filter paper test, and both chemicals have been identified
as low toxicity in the acute soil tests. However, both pyrethroids
have profound chronic and cytotoxic toxicity at very low concentrations
(2.0 and 0.5 mg kg−1) far beyond the LOEC values based
on the acute test (25 mg kg−1). Data from present study provided
a necessary supplement for a sound toxicity classification of
deltamethrin and fenvalerate in soil. The study also confirms that
the inevitable potential risk of deltamethrin and fenvalerate at low
concentrations together with the toxic metabolites, which should
be accounted in the assessment of ecological risk of pyrethroids in
soil.