Levels of Lead, Cadmium and Mercury were assessed in tissues of Callinectes amnicola and Macrobrachium vollenhovenii sampled for twelve months from the Cross River Estuary, Nigeria with the aim of evaluating their potential ecological risk. Results of analysis with Atomic Adsorption Spectrophotometry showed that for C. amnicola, Pb ranged from 0.02-0.19µg/g, Cd 0.01-0.049µg/g and Hg 0.01-0.071µg/g; for M. vollenhovenii, Pb ranged from 0.019-0.098µg/g, Cd 0.0085-0.04µg/g and Hg 0.01-0.058µg/g. Paired t-test showed no significant seasonal disparity (P>0.05) for both crustaceans. Observed linear relationships were expressed as y = 0.4825x 0.0137, y = 0.5661x+0.0053 and y = 0.6111x+0.0059 for Pb, Cd and Hg respectively. Also, the correlation coefficient of Pb (r= 0.87), Cd (r=0.78) and Hg (r=0.803) showed significant concentration relationship between the two studied crustaceans. Although the results of this study show minimal toxicity of shellfish in Cross River estuary, continuous surveillance and assessment were recommended for sustainable ecosystem management.
Keywords: Heavy Metals, crustaceans, tropical ecosystem
