Acetylcholinesterase: a potential biochemical indicator for biomonitoring of fertilizer industry effluent toxicity in freshwater teleost, Channa striatus

Monitoring of acetylcholinesterase (EC: 3.1.1.7, AChE) activity has been widely used in aquatic and terrestrial systems as an indicator of pollutant exposure. The reports regarding impact of fertilizer industry effluent on the level of AChE activity are very scanty. In this paper, an attempt has been made to investigate the in vitro impact of fertilizer industry effluent upon the levels of AChE activity and protein content in different tissues of non-target aquatic fish, Channa striatus (Bloch). The fish when exposed to three sublethal concentrations (3.5, 4.7, and 7.0%; v/v) of fertilizer industry effluent for short (96 h) and long (15 days) durations registered sharp reduction in the levels of AChE activity (15-75%) and protein (10-71%) in different fish organs. The highest effluent concentration treatment for short or long duration, the fish brain and gills registered significant (P < 0.001) inhibition (64-75%) in the activity of AChE whereas other organs such as muscles, liver, and heart exhibited slightly lower inhibition (40-59%) in enzyme activity. However, kidney of C. striatus was the only organ where very less effect (14-18%) of the effluent was observed on the activity of AChE when the fish were exposed to all the three concentrations of the effluent for both treatment durations. This effluent also induced alterations in the level of protein in different fish organs; in kidney the effect was pronounced only at higher concentrations at both treatment durations. The most affected organs were muscle and gills where in 60-71% reduction in the protein content was recorded due to highest effluent concentration treatment at short or long durations. The results of present study indicated that the fertilizer industry effluents might significantly influence the neurotransmission system and protein turnover in the non-target organisms after exposure even at very low concentrations. Further, the data suggested that the fish AChE could be used as a potential biochemical marker for fertilizer industry effluent pollution in aquatic systems.