Coastal heavy metal pollution in a tropical seagrass ecosystem in Indonesia

Abstract: Densely populated coastal areas are exposed to an array of anthropogenic pollutants. Heavy metals are one of the most serious pollutants in the marine environment due to their persistence, bioaccumulation, and high toxicity characteristics. Analysing the severity of environmental pollution gradients provides an insight into the extent of anthropogenic impacts on the surrounding ecosystem. This study analysed the surface sediments and leaves of two seagrass species, Thalassia hemprichii and Enhalus acoroides, from a seagrass meadow surrounding Barrang Lompo island, in the Spermonde Archipelago, Indonesia as well as muscle tissue from two herbivorous fish species, Siganus canaliculatus and Crenimugil buchanani. ICP-MS and ICP-OES were used to determine the concentrations of two major metals (Al, Fe) and eight trace metals (Cd, Co, Cr, Cu, Li, Ni, Pb, and Zn) in the environment, habitat-forming primary producers and primary consumers. Results from both sediment and seagrass tissue evidenced an exponential increase in the Metal Pollution Index (MPI) and in the concentration of most individual metals towards the island (k = 0.01–0.08 m–1) with a clear impact radius of approximately 100 m. The comparative analysis of both seagrass species further revealed interspecific differences in metal loads. Finally, this study provides evidence of trophic transfer to two commercially important fish species which can have ecological consequences as well as human health implications for the local population. This study highlights the need for monitoring and regulation of environmental contamination levels, especially in areas where hazardous waste management is inexistent or inefficient.