An integrated use of histological and ultra-structural biomarkers in Mugil cephalus for assessing heavy metal pollution in east Berbice-Corentyne, Guyana

Abstract

Bioaccumulation of heavy metals and its associated histopathological perturbations were studied in various tissues of Mugil cephalus collected from polluted and compared with the fish collected from less polluted of Corentyne coast. The concentration of copper, lead, zinc, cadmium, manganese and iron were quantified in gills, liver and muscle. The results showed marked differences between the two sites as well as significant variations within the tissues. The decreasing trend of metals in the tissues of fish sampled from both polluted and less polluted sites was in the order of Fe >Mn > Zn > Cu > Pb > Cd. Overall, the highest metal concentrations were found in the fish collected from polluted site. The accumulation in the gills and liver of M. cephalus was found to be quite high in comparison with the muscle. These tissues were further investigated by light and electron microscopy and the results were compared with the reference site (Less polluted). The presence of large lipid droplets in liver and increase of mucous cell in gill were some of the most noticeable alterations observed and were related to heavy metal contaminates. It is concluded that histopathological and ultrastructural biomarkers provide reliable and discriminatory data to augment heavy metal pollution in polluted site of Coretyne coast. Therefore, long-term monitoring is necessary to assess the untreated waste water discharged directly and indirectly into the water ways of Corentyne coast led to a reduction in waste assimilative capacity of the coastal marine waters, which provide accurate, reliable measurements of environmental quality.