Abstract

SEASONAL VARIATIONS OF MERCURY IN EDIBLE TISSUES OF LABIO ROHITA AND CATLA CATLA

Geeta Singh*

Abstract

Mercury is a toxic heavy metal which is widely dispersed in nature. Fish are a valuable source of high-grade protein and nutritious component of the human diet and occupy an important position in the socio-economic conditions of south Asian countries. Fishes have a natural tendency to concentrate mercury in their bodies, often in the form of methyl mercury, a highly toxic organic compound of mercury. The two most commercially important fresh water fish species namely; Labio rohita and Catla catla were collected from different fish markets of Agra city and analyzed for the Mercury concentration. The present study is undertaken to gauge the accumulation of Mercury in tissues of Labio rohita and Catla catla seasonally. The metal concentration was evaluated using a Perkin Elmer AA analyst 100 atomic absorption spectrophotometer. Wet digestion method was used for analysis of metals with nitric acid and sulfuric acid. The heavy metal concentrations ranges of Hg detected in Labio rohita and Catla catla were 0.01-32.0 and 0.01-23.0 g kg-1respectively. The frequency of heavy metal contamination was higher in Labio rohita followed by Catla catla. Similar trend of seasonal variation in metal concentrations were observed in both the species. The highest concentrations were observed in summer followed by winter and rainy seasons. The present study showed that the levels of mercury are different in both the fish species but within the maximum residue levels recommended at National and International standards.

Keywords: Heavy metals, mercury, Seasonal variation, fish.