CONTENT OF SOME HEAVY METALS IN COMPOUND FISH FEEDS IN NORTHERN NIGERIA

Abstract

This study was carried out to determine the concentrations of zinc, copper, nickel, arsenic and lead in four brands of compound fish feeds (Aqua® , Multi® , Top® and Vital®) obtained in Northern zones (North Central, North West And North East) of Nigeria. Five samples of each of the brands were respectively collected from five different distributors in each of the three zones. The composite samples were prepared by the standard dry ashing method and the concentrations of heavy metals were determined using Atomic Absorption Spectrophotometry (AAS). The results obtained revealed that Vital® feed contained mean concentrations of 11.326 mg/kg and 6.501mg/kg for zinc and copper respectively, higher than the other brands. The concentrations of these essential elements in the feeds were lower than the standard permissible limits. Multi® feed contained the highest mean concentrations of nickel (0.653mg/kg) and arsenic (0.072mg/kg) while Aqua® feed had the highest mean concentration of lead (2.690 mg/kg). There were no significant differences (p<0.05) in concentrations of the heavy metals in all the brands of fish feeds sampled within and across the three zones. Overall,the concentrations of copper, zinc, lead, arsenic and nikel found in the four compound fish feeds were below the permissible limits stipulated by the European Union. Despite these findings, more stringent measures are recomended to avoid contamination of the feeds with lead and arsenic, which are known public health risks.