3.10. Risk to the environment
The risks of pesticide inputs to the environment also vary
with the toxicological, physical and ecological properties of
the respective active ingredients. At current pesticide
application rates in rice and corn fields, drift of the
insecticides lambda cyhalothrin and cypermethrin is toxic
to aquatic species. Estimated a.i. concentrations in water
affected by drift in channels 0.5, 1.0 and 2.0m from field
borders (Table 8) exceed the maximum tolerable risk levels
and in one case (cypermethrin at 0.5m near a corn field)
the LC50 level (see MTR and LC50 data in Table 3).
However, the same application rates are not toxic to
honeybees exposed to drift at 0.5, 1.0 or 2.0m from a field,
as hazard quotients are far below 50 for all pesticides
(Table 8).