Lead and Zinc Concentrations in the Gill, Liver and Parasito-Fauna of Sarotherodon melanotheron iIn Makoko Lagoon, Lagos State, Nigeria

Abstract

Morphometric and meristic features, metal accumulation and chemical composition of Sarotherodon melanotheron and its intestinal parasites were investigated in August, 2013. The Standard length of Sarotherodon melanotheron range between 13.10-21.50 cm with Mean ± SD of 16.15 ± 1.97, (p<0.001) and Head length range from 1.50-2.70 with Mean ± SD of 2.15 ± 0.28, (p<0.001). Heavy metal concentrations were determined in water, sediment, intestinal parasites, gills and liver of Sarotherodon melanotheron were analysed using Atomic Absorption Spectrophotometry to determine concentration of Pb and Zn. Metals in the water, sediment and parasites were above WHO level. The concentration of Lead and Zinc were higher in the sediment (Pb-18.82 and Zn-21.52) than the water (Pb-2.66 and Zn-15.41). The liver accumulated highest concentration of Lead and Zinc than the gill and parasite. The trend of lead accumulation was; gill (0.86)<parasite (0.98)<liver (3.54). This accumulation followed similar trend in zinc sampled, the mean concentrations for zinc; parasites; (Zn) (mg/l); 3.39, p<0.01, gill; (Zn)(mg/l); 0.72, p<0.01, liver; (Zn) (mg/l); 11.04, p<0.01. Fish parasites, particularly intestinal acanthocephalans and cestodes, accumulated heavy metals at concentrations significantly higher than those in fish tissues or the environment; hence, they could be used as bioindicators of heavy metal pollution. It is important to continue monitoring heavy metals concentration in waters, sediments and fish of Makoko lagoon so as to assess trends in heavy metal behavior in the area.