Citation:Hemachandra, C.K., Pathiratne, A. and Pathiratne, K.A.S., 2008. Monitoring anti-cholinesterase contamination in Bathalagoda reservoir, Sri Lanka, Proceedings of the Annual Research Symposium 2008, Faculty of Graduate Studies, University of Kelaniya, pp 117.
Date:2008
Abstract:
Organophosphosphorus and carbamate pesticides are widely used in Sri Lanka for
agricultural pest management. They may enter inland water bodies draining agricultural
watersheds and affect aquatic fauna including fishery resources. These pesticides are
considered as anti-cholinesterases as they could inhibit the cholinesterase enzymes including
acetylcholinesterase which plays an important role in maintaining normal functioning of
the nervous system. Hence monitoring of anticholinesterase contaminations in inland water
bodies is important yet difficult due to low persistence of many of these pesticides. In the
present study, anticholinesterase contaminations in Bathalagoda reservoir, located in the
vicinity of agricultural lands in Kurunagala District were monitored bimonthly during the
period September 2007 to June 2008 using brain and muscle cholinesterases (ChE) of feral
Nile tilapia (Oreochromis niloticus), as a biomarker (n=IO). ChE activities were measured
using standard methods established for this fish. The results show that ChE activities in
brain and muscle tissues in feral fish were depressed significantly in comparison to the
laboratory reared control fish by 57-72% and 59-78% respectively in September 2007 and
December 2007. There were no significant gender specific differences in the ChE levels
of the feral fish at each sampling stage. The brain and muscle ChE activities in the fish
collected from the reservoir at each sampling stage were negatively correlated (p < 0.05)
with the rainfall in the area. The depression of ChE levels in the brain and muscle tissue of
feral tilapia may indicate the exposure of fish to anti-cholinesterase contaminations present
in the reservoir during rainy periods.
