Analysis of Heavy Metals Concentration in Prawn (Macrobrachium Sp) Harveted from Gberikoko River, in Sapele Delta State; Nigeria

Abstract

The concentrations of selected heavy metals: cadmium, arsenic, lead and mercury in prawn (Macrobrachium sp) were analyzed. The morphometric records of the prawn samples were taken.  The specimens were subsequently weighed and individually pulverised to a uniform particle size. Ten(10)grams of each pulverised sample were put in a 200ml digestion conical flask, 30ml of aqua regia, which constitutes of hydrochloric acid, nitric acid and hydroflouric acid in the ratio 1:3:1 was added and placed uprightly for 10-15 minutes. The mixture was heated in a waterbath until the whole sample dissolved and a yellow tint of the solution appeared. The solution was filtered using a filter paper into centrifuge tubes and made up to 50ml mark with deionized water. It was transferred into sample vials for analysis. The heavy metal analysis was done according to the standard methods for heavy metal determination using the FS 240 Varian Atomic Absorption Spectrophotometer. Lead had the highest concentration in sample F and the lowest in sample H, with concentrations of 1.75ppm and 1.54ppm respectively. Also, the prawn samples exhibited the highest record of Mercury and lowest mean value of Arsenic with values of 6.9±3.95and0.00±0.00 respectively. For Mercury, the highest concentrations occurred in sample G and lowest in F, with concentrations of 12.6ppm and 4.1ppm respectively. Arsenic showed its highest concentration in sample F and lowest in sample H with concentrations of 0.65ppm and 0.64ppm, respectively, whereas Cadmium wasn't  detected in any of the samples. From the analysis of data, since F > F_crit and p < 0.05, there is a significant difference in the mean concentrations of the prawn samples from Gberikoko river in Sapele, Delta State Nigeria.