SOME TOXICOLOGICAL STUDIES Of the herbicide (glyphosate)on Oreochromis niloticus fish

Abstract

The extensive and unwise use of synthetic pesticides has created problems which are more serious than those for which they were originally applied and resulted in a public anxity concerning their effects on the environment and its subsequent pollution. Herbicides are one group of these pesticides which used in the aquatic or terrestrial

environments as weed killers to control many weeds and grasses.

The continuos use of the herbicides may lead to chemical contamination of the adjacent land drainage water, this water are used in some farms under a decision from the General authority for fish resource development instead of the drinking water which used in hmnan and animal consumption.

Fish and other aquatic animals living in such water either in land drainage canal or fish farms using this polluted water are unable to escape from these chemicals once they reached the water and will be exposed to several hazards until these chemicals are removed from water by adsorption, sedimentation, leaching, degradation or other mechanisms, Afifi et al., (2002) .

These hazards may cause economic losses because the fish will lost by death or stressed or weakened and may be very susceptible to many infectious diseases. (Shepherd and Bromage, 1988), or most of the applied chemicals will be introduced into the food chain by accumulating in the fish flesh which will be consumed either as fish meals for animals or consumed by human. Glyphosate was first announced as a new herbicide in (1971), (Baird et al., 1971) and marketed in U.S.A in 1974. In 1976 glyphosate had been