METALLOTHIONEIN INDUCTION ON EXPOSURE TO CADMIUM IN MARINE CATFISH ARIUS ARIUS
Environmental health is of great concern, as aquatic environment is exposed to a variety of xenobiotics mainly heavy metals in marine water ecosystems. Heavy metals in aquatic organisms tend to accumulate in the human tissues and organs by way of food chain. One of the way to regulate the level of metals in the cells is to immobilize the heavy metals by binding to biological molecules such as Metallothionein (MT). Cadmium (Cd) is a ubiquitous trace metal, biochemically classified as a nonessential element. It occurs naturally in the aquatic environment and is released as a result of anthropogenic activities and natural processes. The objectives of this study were to determine the Cd levels and MT induction in liver, kidney, brain and gill of marine catfish Arius arius during acute Cd exposure, to study of the relationship between tissue-specific Cd accumulation and MT induction. Cd accumulation and MT induction levels were determined by the Cd saturation method and inductively coupled plasma optical emission spectrometry (ICP-OES). Cd concentration was expressed as µg g-1 wet weight tissue. The results showed that MT induction significantly in all the tissues studied after Cd exposure in the following order: Liver > Kidney > Gill > Brain. Positive correlations were showed between Cd accumulation and MT induction. In conclusion, the results indicated that Cd exposure clearly resulted in MT induction and hence MT induction can be considered as a biomarker for waterborne Cd pollution