Assessment of Heavy Metal Concentrations on Fish Flesh Smoked Using Polythene Products

Abstract

Fish continues to be the main source of animal protein worldwide, yet trace metal pollution endangers them. Trace metal pollution originates from nature and human activities and poses public health risk to consumers of these fish. This study was conducted using fresh fish samples weighing 600g. Fish samples were divided into four groups: Group I: fresh fish sample not roasted (Control); Group II consisted of fish roasted with fire wood (FRF); Group III had fish roasted with waste vehicle tyres (FRT) and Group IV were fish roasted with plastic materials (FRP). Roasting time was four hours at high temperature. Trace metals {cadmium (Cd), lead (Pb), zinc (Zn), iron (Fe), and copper (Cu)} were determined using acid digestion and Atomic Absorption Spectrophotometric. Results revealed the highest cadmium value (0.81±0.042 mg/kg) in fish samples roasted with waste vehicle tyres. This was followed by fish roasted with plastic materials (0.715±0.021 mg/kg) and thereafter, fish roasted with firewood (0.59±2.51mg/kg). The highest zinc (212.185±0.0 mg/kg) was recorded in fish roasted with plastic materials. This was followed by fish roasted with firewood (2.57±0.042 mg/kg). The mean values for iron were: FRT (7.965±0.035mg/kg), FRP (7.82±0.014mg/kg) and (6.705±0.035mg/kg) for FRF. Values for copper were 1.725±0.063mg/kg for FRT, 1.335±0.007mg/kg for FRP and 0.86±0.028mg/kg for FRF. Concentration of lead was negligible in FRF with higher values (1.485mg/kg) in FRF and (2.865mg/kg) in FRT. Fish in control group had no metal deposit in their tissues. The results of the present study have revealed that cadmium and lead concentrations in the muscles of all fish samples roasted with waste vehicle tyres and plastic materials were above permissible limits of 0.5 mg/kg set by European Commission. Thus, using these materials to generate heat in fish smoking is of great public health concern. Individuals and authorities at the Local, State and Federal level should co-operate to expose this unhealthy practice and devise strategies to eliminate it.