Bioaccumulation of Toxic Heavy Metals in Fish after Feeding with Synthetic Feed: A Potential Health Risk in Bangladesh

Abstract

This present research was conducted to assess the bioaccumulation of toxic heavy metals in fish before and after six months feeding with synthetic feed. Here in concentrations of eight toxic heavy metals such as chromium (Cr), copper (Cu), cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn), iron (Fe) and manganese (Mn) were determined by atomic absorption spectrophotometric (AAS) method. Before feeding, the concentrations in fish were found to be 19.5 ppb, 61.8, 30.5, 35.3, 123.3, 121.9, 197.7 and 543.2 ppb, respectively. And after feeding with synthetic feed, the concentrations were found to be 22.1 ppb, 101.5, 37.7, 102.0, 147.6, 214.1, 175.8 and 508.0 ppb, respectively. Contents of the trace metals in the feed, fresh water and the water after addition with synthetic feed were also evaluated. The Labeo rohita locally known as "Rui fish" has been selected for this study since it is a very popular fish in the rural as well as in urban peoples of Bangladesh. The accumulation of beneficial elements i.e., Cu, Zn, Fe and Mn were found to be within the permissible limit in both the fishes of before and after feeding with the synthetic feed. Concentrations of potential toxic metals i.e., Cd, Pb and Ni (37.7 ppb, 102.0, and 147.6 ppb, respectively) accumulated in the fish after six months feeding were found to be much higher than that of the recommended permissible limit. Concentrations of Cd, Pb and Ni (21.6 ppb, 102.0 and 114.0 ppb, respectively) in the synthetic feed used for feeding were also found to be much higher than the WHO/EU recommended value. Considering the potential health risk issues, it is recommended that the use of natural feed should be encouraged for feeding despite the synthetic feed in the fish firming project.