Analysis of Bio-Accumulation of Heavy Metals in Cultured andWild Fish from Niger and Kaduna State in Nigeria

Abstract

Accumulation of some heavy metals iron manganese copper lead and zinc in the muscle, gills, intestine were determine in some fishes (clarias garinepinus and oreochromis niloticus). They were bought from fishermen at the landing site of Shiroro dam and Tagwai dam. and also purchased from Danjeo farm and Federal University Of Technology farm minna (Water Resources and Aquaculture Department Farm).The Sample were collected once monthly for a period of six months Prior to digestion, samples were rinsed with flowing water and dissected with sterile dissection tools to get rid of the gills, muscle and intestine. Wet method of digestion was used to carry out the analysis. The weight of the two fish species was taken and 1 g of each sample was first weighted.1g of each sample was dissolved in 10ml nitric acid and was boiled to complete the dissolution using hotplate .After digestion samples were filtered using filter paper number 41 and obtained precipitate was make up to 20ml with distilled water and transferred into 25ml volumetric flask and then analyzed by atomic absorption spectrophotometer (AAS). The accumulation of the heavy metals in different organs showed significance difference(p<0.05) except lead accumulation. Zinc concentrations in the cultured fish species were in the range of 0.6 to 2.6 mg/L whereas in the wild species values varied between 0.8 and 2.1 mg/L. The greatest zinc concentration was found in the intestine of Clarias gariepinus and Oreochromisniloticus from Danejo farm. Zinc concentration in the gill of Clarias gariepinus and Oreochromis niloticus from Danejo farm was statistically similar to those in the intestine of Clarias gariepinus and Oreochromis niloticus from FUT minna farm and Shiroro dam, as well as gill and intestine of Clarias gariepinus and Oreochromis
niloticus from Tagwai dam.