Heavy Metals Bioaccumulation Assessment in acanthopleura gemmata from Fort Jesus Mombasa

Abstract

The availability and the levels of heavy metals contamination was assessed in marine mollusk species Acanthopleura gemmata from Fort Jesus, Mombasa Kenya. The levels of heavy metal contamination in flesh and shells of Acanthopleura gemmata were compared with that of marine algae U. Lactuca and U. Reticulata species, water and sediment in its environment. The heavy metals investigated included Fe, Cu, Mn, Zn, Pb, Cr and Cd and were assed using atomic absorption spectroscopy (AAS). The results of this study indicated that the concentrations of all the heavy metals were high in the flesh samples of Acanthopleura gemmata as compared to the algae, shells, water and sediments samples. The concentrations of heavy metals varied with the size of the organism. The smallest Acanthopleura gemmata had the high concentrations of Zn: 347.75 ± 31.66 μgg-1, and Cd: 13.92 ±1.24 μgg-1. The largest Acanthopleura gemmata on the contrary had high concentrations of Fe: 3182.01±41.30 μgg-1, Pb: 67.43±0.81μgg-1 and Cu: 53.07±2.87μgg-1. Cr and Mn were below detection limit in flesh samples but the concentrations were 25.71±5.72 μgg-1 for Mn and 29.11±8.75 μgg-1 for Cr in the shells. The concentration of Cd was below detection limit in algae, water and sediment samples. The findings from this study indicated that Acanthopleura gemmata are good bioaccumulators of heavy metals as compared to water and sediments. The results further showed that metal bioaccumulation is dependent on both the size of the Acanthopleura gemmata and the type of heavy metal