Brain AChE activity studies in some fish species collected from a mercury contaminated estuary

In an attempt to investigate the impact of the discharge of Hg contaminated effluent from a chlor-alkali industry into the Rushikulya river estuary, brain AChE activity was measured in three fish species, S. sihama, A. nenga and S. argus, sampled from the contaminated water of the estuary. The residual Hg levels in the brain tissue of the fishes were also determined. The maximum brain residual Hg level, 0.702 ± 0.205 mg kg^?1 ww, was recorded in S. sihama. The inhibition of the AChE activity observed in that species was as much as 26.48% when compared to the normal enzyme activity. The levels of inhibition. observed in the other two fish species, A. nenga and S. argus, were also more than the 10% index level suggested. A significant negative correlation observed between the brain residual Hg levels and the AChE activity levels suggested the use of fish brain AChE measurement as a regular monitoring protocol in assessment of the pollution of aquatic systems by Hg.