Heavy metals contamination in Jakarta Bay sediment: geoaccumulation assessment and implication for environmental health

Heavy metal contamination in marine environments has gained increasing attention due to their accumulation in edible marine organisms, posing potential risks to food safety and human health. This study examines heavy metal contamination in marine sediments from Jakarta Bay, focusing on cadmium (Cd), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn). Environmental indices, including the enrichment factor (EF), geo-accumulation index (I_geo), contamination factor (CF), and pollution load index (PLI), were used to assess contamination severity. Average metal concentrations were observed in the order Fe > Zn > Cu > Ni > Pb > Cd, with higher levels near coastal stations, indicating hotspots of pollution. Zn was identified as the primary pollutant, followed by Pb and Cd, likely due to anthropogenic runoff. Comparison with sediment quality guidelines indicated that the contamination poses significant risks to the local marine ecosystem, potentially disrupting biological functions and harming benthic organisms especially near coastal areas. Strong correlations with clay content and Fe suggest that most metals cycle with common geochemical phases, except Ni, which shows a different behavior probably due to its association with the crystalline structure of minerals and potential influences from sediment trapping in deeper areas or long-distance transport.