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Abstract:
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Poisoning by pesticides from agricultural fields is a serious water
pollution problem and its environmental long-term effect may result in the
incidence of poisoning of fish and other aquatic life forms (jyothi and
Narayan, 1999). Fishes like Heteropneustesfbssilis and C/arius batrac/nus are
especially prone to serious pesticide pollution as their habitat is mostly the
agriculture area. Though only few studies are conducted in this area, it can
be assessed from the local information that, population of such fish is on
the verge of vulnerability due to extensive use of pesticides. The knowledge
of sublethal effects of xenobiotic compounds on hematological parameters,
enzyme activities and metabolite concentrations is very important to
delineate the fish health status and provide a future understanding of
ecological impacts. These pesticides act by causing inhibition of
cholinesterase enzymes (ChE) by formation of enzyme inhibitor complex
(O'Brien, 1976) and damaging the nervous system. These effects may result
in metabolic disorders. Associated to cholinesterase activities, a study of
other enzymes such as phosphatases and aminotransferases close to
intermediary metabolite determination provides a wider view of
metabolism. Interest in toxicological aspects has grown in recent years and
research is now increasingly focused on mechanistic aspects of oxidative damage and cellular responses in biological system. The term ‘biomarker’ is
generally used in a broad sense to include almost any measurement
reflecting an interaction between a biological system and a potential hazard,
which may be chemical, physical or biological (WHO, 1993). As biomarker
stands for immediate responses, they are used as early warning signals of
biological effects caused by environmental pollutants.
The present work attempts to assess the toxicity of organophosphorus
insecticide monocrotophos on the experimental organism selected for this
study namely stinging catfish (Heteropneustesfossi/is) (Bloch), and to probe
into the stress responses of the organism |