Potential Sources and Contamination Levels of Pb and Ni in Surface Sediment of Lampung Bay, Indonesia

Sediment in Lampung Bay has been reported to contain heavy metals, but information on their sources and the level of contamination is limited. This study aims to estimate the sources of lead (Pb) and nickel (Ni) and the extent of their contamination. Five locations were chosen to collect sediment samples, and heavy metal concentrations were determined by geochemical partitioning using the Sequential Extraction Procedure Bureau Commune de Reference of the European Commission (SEP BCR) method. The results showed that the total Pb concentration ranged within 12.48–24.46 mg/kg, dominated by the residual fraction (9.62–23.74 mg/kg) compared with the non-residual fraction (0.21–0.55 mg/kg). The total Ni concentration ranged within 7.48–13.70 mg/kg, also dominated by the residual fraction (2.95–7.96 mg/kg) compared with the non-residual fraction (2.54–5.75 mg/kg). These results have not exceeded the quality standards set by the Australian and New Zealand Environment and Conservation Council (ANZECC). The dominance of the residual fraction in both metals suggests that natural sources are the primary origin. The level of contamination was assessed using the enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), and pollutant load index (PLI). In general, the sediments of Lampung Bay have been contaminated and enriched by Pb and Ni. However, the enrichment remains harmless to organisms and the aquatic environment. The SEP BCR method can be used to determine the partitioning of heavy metals in marine sediments and estimate the sources of natural or anthropogenic inputs, making it a valuable tool for initial monitoring related to assessing the sources and extent of heavy metal contamination in marine sediments.