Spatial profile of trace elements in marine sediments from Jakarta Bay, Indonesia

Jakarta city has the largest urban population in Indonesia. The rapid expansion of industrial activity and chemical pollution of Jakarta Bay is a matter of concern. We studied the spatial and temporal variations of trace elements contamination in the Bay by analyzing nineteen surface sediment samples from Jakarta Bay using handy type X-ray fluorescence analyzer (XRF). Influences of different anthropogenic activities on the composition of the sediments were also evaluated. Degree of heavy metals contamination such as Zn, Cu and Pb were generally higher in coastal sites than offshore. Enrichment factors (EFs) defined as the ratio of metal levels in coastal sites to offshore were higher in coastal sites. This result agreed with geoaccumulation index, which reflects the degree of anthropogenic contamination of the metals, indicating that the sediments in Jakarta Bay can be classified as uncontaminated to moderately contaminated. Apparent anthropogenic impact on metal levels does exist in the Jakarta Bay though the degree of contamination is still moderate.