Effects of heavy metal Cd on essential metal Zn levels in freshwater fish Channa gachua

Document Type : Primary Research paper


1 Department of Zoology, Government College University Lahore, Pakistan

2 Department of Chemistry, University of Malakand Khyber Pakhtunkhwa, Pakistan

3 Department of Zoology, University of Malakand Khyber Pakhtunkhwa, Pakistan

4 Department of Environmental Sciences, University of Swat Khyber Pakhtunkhwa, Pakistan


Heavy metal pollution is a key threat to aquatic ecosystems and associated biodiversity. Current study highlights the heavy metal pollution (Cd) and its impacts on Zn level in snake head fish channa gachua. Total of 42 individuals were collected from river Barandu KP, Pakistan. Out of which n=36 individuals of fish were arranged into one control group and five experimental groups I, II, III, IV and V (each having n =6 individuals) were treated with different concentration of Cd solution 0.1, 0.5, 1.0, 2.5 and 5.0 ppm respectively for 90 days. After treatment, sample were analyzed for Cd bioaccumulation and Zn level in liver, gills and muscles tissues of fish. Highest Cd bioaccumulation and lowest Zn level were recorded in group V (at 5.0 ppm treatment); mean value of Cd concentration in liver 107.73±45.14 mg kg-1, gills 36.40 ±0.435 mg kg-1 and in muscles 36.20 ±0.458 mg kg-1 and Zn level of 14.56 ± 15.07 mg kg-1, 16.76 ± 1.35 mg kg-1, and 4.60 ± 0.72 mg kg-1 in liver, gills and muscles respectively. While highest Zn level were recorded in Control group with mean value; liver 51.56 ± 23.04 mg kg-1 , gills 26.20 ± 2.81 mg kg-1 and muscles 15.10 ± 1.17 mg kg-1. The Zn level were found declined with the bioaccumulation of Cd in different tissues of fish. The declined order of Zn level in liver were 51.56 mg kg-1 > 24.43 mg kg-1 > 23.03 mg kg-1 > 21.06 mg kg-1 > 16.80 mg kg-1 > 14.46 mg kg-1 in control group, I, II, III, IV and V respectively. The same order were found in gills and muscles tissues also. Current report indicated that Cd has considerable effect on trace element Zn level and would be valuable contribution on this regard.