Lead bioaccumulation in the shell and soft tissues of Asian Green Mussel (Perna viridis) from Bacoor Bay, Cavite, Philippines

Abstract

This study determined lead distribution in the shell and soft tissues of Perna viridis (Asian green mussel) from Bacoor Bay based on the bioaccumulation indices for water (BWAF) and sediments (BSAF). Condition Index (CI) and Micronucleus Cytome Assay (MNcyt assay) were also used to establish correlation between lead concentration and the physiological and hemocytic integrity of the mussels. Heavy metal analysis using Atomic Absorption Spectrophotometry (AAS) revealed a significantly higher lead concentration in the soft tissues than in the shells, 0.446±0.008 ppm> 0.444±0.007 ppm. Moreover, BWAF values for the shell and viscera appeared to be significantly higher compared to their BSAF values having a P- value of 0.00 < 0. 05. No clear correlation was established between the calculated CI values and the lead content in the soft tissues. Nevertheless, the frequencies of hemocytes with micronucleus and necrosis turned out to be significantly correlated with lead concentration. The heavy metal analysis generally indicates the high lead bioaccumulation capacity of Perna viridis. It can be stated from the BSAF and BWAF values that P. viridis mostly accumulate lead from its surrounding marine water. Lastly, the established correlation between the CI values, hemocyte nuclear aberrations and lead concentration suggest that the effects of lead pollution may not always manifest visible results based on the physiological condition of marine organisms. Thus, a more sensitive method to determine the genotoxicity of heavy metals can be used in biomonitoring, such as the MNcyt assay used in this study.