According to the toxic tests conducted in this study,
both substances tested were characterized from “very toxic”
to “extremely toxic”. It is evident that the repercussions are
owed greatly to the main substance methomyl, as its LC50
values are very similar to those of the commercial product
(Lannate).
Comparing the fish bioassays used for the toxicity
evaluation of Lannate, tilapia proved to be more sensitive
to the specific pesticide, as the mean lethal concentration
is quite lower than that of the rainbow trout, even though
both mean toxicity values (TU) categorize them in the same
group.
It is estimated that the use of toxicity tests with a single
species results to limited data, so the use of species from
different trophic levels in order to provide more accurate
information is suggested. In similar future studies, the microbiotest
Thamnotoxkit FTM and the tilapia fish bioassay
can be jointly used for an optimal evaluation of the repercussions
and risk assessment of insecticides.
Finally, it is stressed that acute toxicity data of the insecticide
Lannate and its main substance methomyl do not
reverse the necessity of further studies on their chronic repercussions,
in order to reconsider their use or the necessity
of substitution by substances less toxic