Changes in elemental composition of scales of Channa punctatus on treatment with mercury

In the present study different regions in the scales of Channa punctatus were investigated for elemental composition to see the impact of mercury on them. Five sublethal concentrations of mercury were used after calculating the LC50 value which is 1.21mg/L in 96 hours. When focal and lepidontal regions of scales were seen under electron probe analysis (JEOL 8600M), they were composed of four major elements and these are: calcium (Ca); iron (Fe); aluminium (Al); and phosphorus (P). The percent composition of calcium was recorded to be maximum, followed by phosphorus, aluminium and iron. The percent composition of each element upon exposure to mercury was compared to corresponding control and the deviations were observed. When fish was exposed to different sublethal concentrations of mercury for 15d and 30d, an increase was observed in percentage composition of aluminium and phosphorus, whereas reverse trend was noticed for calcium and iron.