Toxicity of Organophoshorous pesticides to the marine alga Tetraselmis Suecica

Organophoshorous pesticides are widely used in agriculture, because most of them are
high effective and low persistent. Yet their increased usage has elicited extensive
research into pesticide effects on non-target organisms, such as algae. Algae are of vital
importance in the primary production of aquatic ecosystems. Furthermore they have been
considered to be indicators of the bioactivity of industrial wastes and they vary in their
response to a variety of toxicants.
However little is known about the toxicity of the new pesticides to marine green algae.
Laboratory toxicity data concerning responses of aquatic organisms to pesticides are
important for focusing on sensitive species exposed to aqueous concentrations of these
pesticides in field studies and they also allow prediction of expected responses of aquatic
species to a range of pesticides concentrations in situ.
The effects of seven organophosphorous pesticides on the green unicellular marine alga
Tetraselmis suecica were studied through 96h toxicity tests. The pesticides tested were
azinphos ethyl, azinphos methyl, dimethoate, fenthion, parathion ethyl, parathion methyl
and disulfoton,. Maximum Specific Population Growth Rates (MSGRs) were calculated for
each pesticide tested. Also NOEC, LOEC values and MATC at 96h were estimated when
compared to the controls.