Heavy Metal Pollutants and their Concentrations in Fish (Barbus Species) in Sosiani River, Kenya

Abstract

The presence of heavy metal pollutants in fish caught from River Sosiani, a small river that passes through Eldoret town, Kenya was studied in February and September, 1995. Heavy metals studied were: Cadmium, Chromium, Lead, Zinc, Copper, Manganese, Iron, Calcium, Magnesium and all these were detected in fish tissues, such as muscles, gills and liver, using Atomic Absorption Spectrophotometer. The levels for different metals varied for different tissues. For example in muscle Cadmium level ranged from 0.0 mg/kg to 0.031(0.02 mg/kg) and Chromium level was from 0.007 (0.01 mg/kg to 0.03). Similar variations were observed for different metals in liver and gills. Magnesium, Calcium, Zinc and Iron levels were the highest in this analysis for fish tissues. Two factor Anova showed significant variation in the mean metal concentration at 5% level of significance in September at Huruma and 20% level of significance for Ellingirini Dam in the same month. In February two factor Anova showed significant variation at 20%, 5% and 1% level at the same sampling points. The level of mean metal concentrations in the fish tissue and samples analysed were lower than the recommended WHO values. Discovery and Innovation Vol. 13 no. 3/4 December (2001) pp. 178-183 KEY WORDS: heavy metal pollutants, tissue concentration, environmental concern, depletion, industrial applications Resume La presence de metaux lourds polluants dans les poissons peches du fleuve Sosiani, un petit fleuve qui traverse Eldoret, a fait objet d'une etude en fevrier et septembre, 1995. Les metaux lourds etudies etaient le cadmium, le chrome, le plomb, le zinc, le cuivre, le manganese, le calcium, le magnesium. Tous ces metaux ont ete detectes dans les tissus de poissons tels que muscles, branchies et foie, au moyen d'un spectrophotometre d'absorption atomique. La concentration de divers metaux a varie pour differents tissus examines. Par exemple dans les muscles, la concentration du cadmium est allee de 0,0 mg/kg a 0,031 (0,02 mg/kg), tandis que le chrome allait de 0,007(0.01 mg/kg) a 0,3 (0,02 mg/kg). Des variations similaires ont ete observees pour differents metaux dans le foie et les branchies. Les concentrations du magnesium, du calcium, du zinc et du fer etaient les plus elevees dans les tissus examines. L'ANOVA bi-factoriel a montre une variation significative dans la concentration moyenne de metaux, au seuil de 5% de signification, en septembre a Huruma, et 20% de signification pour le barrage d'Ellingirini, a la meme epoque. L'ANOVA bi-factoriel pour le mois de fevrier a montre une variation significative au seuil de 20%, 5% et 1%, aux memes points d'echantillonnage. La concentration moyenne des metaux dans les tissus de poissons et autres echantillons analyses etait inferieure aux normes recommandees par l'OMS. Discovery and Innovation Vol. 13 no. 3/4 December (2001) pp. 178-183 Mots-cles: metaux lourds polluants, concentration dans des tissus, probleme environnemental, degradation, traitements industriels