Study on the effects of sub-lethal exposure of cadmium on thetissues of blood clam, Cardiata antiquata (Reeve) from Mumbai coast

Girgaum Chawpatty is one of the prime sites for religious and political activities. During Ganapati festival the immersion of Ganapati idols is performed while within Marine drive region there are two sites of release of domestic sewerage. Cadmium is one of the major components of dyes and chemicals used and domestic sewerage; there are every chances of the cadmium being present in these regions. Blood clam has been found to be present in quite large numbers. There fore, it was thought to carryout the study of effects of exposure of cadmium on blood calm. Enzyme activities like acid phosphatase (ACP), alkaline phosphatase (ALP), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), succinate dehydrogenase, lactate dehydrogenase and adenosine tri- phosphatase (ATPase) activities reflect on the normal functioning of the tissues. Hence, these enzyme activities were studied in tissues such as gills, hepatopancreas, gonads, muscle, mantle and foot of blood clam, Cardiata antiquata (Reeve) to under stand the effects of cadmium. The healthy specimens were collected form the Girgaum Chawpatty and Marine Drive. The sub-lethal exposure was carried out for 30 days and the values for LC₀ and LC₅₀ were 240 ppm and 340 ppm, respectively. ACP activity was observed to be the maximum in hepatopancreas and decreased gradually in gonads, gills, muscles, foot and mantle among the control set. Acid phosphatase activity was found to be declined in gills and muscle and it was found to be elevated in hepatopancreas, mantle and foot. Exposure of cadmium resulted in decline of alkaline phosphatase activity at LC₀ and LC₅₀ levels in all tissues studied except hepatopancreas and gonads. GOT activity was observed to be low in all the tissues studied at LC₀ and LC₅₀ levels. GPT activity declined at LC₀ level and at LC₅₀ this activity increased in hepatopancreas, gonads and foot but it never reached up to control level. Exposure of cadmium caused decrease in lactate and succinate dehydrogenase activity in all the tissues studied at LC₀ and LC₅₀ levels. Exposure of cadmium caused an increase in ATPase activity in gills; hepatopancreas, gonads and foot of the experimental animal at LC₀ level and there after this activity declined at LC₅₀ level. The enzyme activities studied reflect on the normal functioning of the tissues and it was observed that these activities were found to be affected indicating either stress or trauma in the tissues caused by the exposure of cadmium. It may be envisaged that cadmium present in the ambient medium is likely to be the cause.