Heavy metals and related biomarkers in Perna viridis (Bivalvia: Mytilidae) collected on the coast of Sucre State, Venezuela

Abstract

The green mussel Perna viridis has been used as a sentinel organism in marine and coastal ecosystem health assessments. In this study the degree of contamination at three sites on the coast of Sucre State (Venezuela) was analyzed using molecular, cellular, and immunological biomarkers in P. viridis. Specimens were collected from Chacopata-Guayacán (CG, Araya Peninsula), Río Caribe (RC, Paria Peninsula), and San Antonio del Golfo (SAG, southern Gulf of Cariaco). We determined the concentration of heavy metals in the soft tissue of each individual, as well as the total number, viability, phagocytosis, and stability of the lysosomal membranes in hemocytes. The oxidative damage to lipids (TBARS), sulfhydryl group levels, total proteins, and lysozyme activity were quantified in the digestive gland. The results revealed high concentrations of Zn, Cr, and Cd in the organisms from CG. The total hemolymph cell count was lower in organisms from RC and CG. A slight increase in the number of phagocytes was observed in the organisms from RC and CG relative to those from SAG. The highest percentage of hemocytes with destabilized lysosomal membranes was recorded for the organisms from CG, followed by RC, indicating a weak association with the content of peroxidized lipids (TBARS); these values could be associated with the body loads of heavy metals. According to the results, the mussels from CG show slight signs of contamination by heavy metals, likely originated by human activities. The use of biological markers to estimate the effect of heavy metals on sentinel organisms is recommended.