Occurrence, distribution, and ecological risk of heavy metals using species sensitivity distribution model in Pangkajene river, Indonesia

In this study, we assessed the concentration, distribution, and ecological risk assessment of four heavy metals (Pb, Cd, Cr, and Fe) in the water and sediment of the Pangkajene River, Indonesia. We applied the species sensitivity distribution (SSD) to assess the cumulative probability distribution of the ecotoxicity value of heavy metals from different species. Most of the heavy metal concentrations in river water were higher than the permissible limit (WHO, USEPA, and Indonesian water quality standards). While heavy metal concentrations in sediment were relatively low compared to the permissible value, Analysis of the Heavy Metal Pollution Index (HMPI) and Enrichment Factor (EF) revealed high levels of pollution in both river water and sediment during the wet season (HMPI value > 100; EF > 1.5). In the riverine ecosystem, anthropogenic sources contribute to the enrichment of heavy metals, with the highest HMPI value located near a cement factory. In the wet season, the HQ values of Pb, Cd, and Cr were higher than 1, indicating that potential adverse impacts on the riverine ecosystem are likely to occur. The mean M-ERM-Q value was 0.32 and 0.43 for the dry and wet seasons, respectively. It implies that there is a 21% toxic effect probability of heavy metal contamination of the benthic organism in either season. This study comprehensively reported the quality of the riverine ecosystem using multiple indices. Thus, it can provide information for stakeholders to take action to prevent extensive impacts from heavy metals in the future.