Assessment of heavy metals pollution in the sediment of Ciliwung river

Thirteen (13) rivers flowing in the city of Jakarta and Ciliwung is one of them. This river flows through residential, offices, industrial and factories. Activities that exist around the river can cause rivers to become polluted. River sediments act as a potential sink for many hazardous chemicals that can be used as indicators for pollution monitoring of the river. The objective of this study is to assess the heavy metal contamination in the Ciliwung river sediment based on single and combination indices. For the assessment of the Ciliwung sediment quality, measurements of metal concentration in river sediments have been performed. Sampling was carried out at four sampling locations, namely in Kelapa Dua, Kalibata, Condet, and Depok. Analysis of heavy metals in the sample was carried out using instrumental neutron activation analysis method. The analysis result shows that the detected elements in sediment include: Br, Al, As, Ca, Ce, Cr, Co, Cs, Mg, Mn, Na, Sb, Eu, Fe, Hf, K, Sc, Sm, Ta, Tb, Th, Yb, and Zn. The assessment based on the value of the enrichment factor indicates that there has been an increase in the concentration of heavy metals As, Cr, Sb, and Zn in moderate levels due to anthropogenic factors. Based on the geo accumulation index value, it is known that the sampling area is not polluted to moderate contamination. Heavy metals As, Cr, Sb, and Zn in sediments provide a low level of ecological risk to the aquatic environment. Based on the pollution load index value (PLI), all sampling locations are in no pollution conditions. From the evaluation, it can be seen that even for some heavy metals namely As, Cr, Sb, and Zn has been an increase in the concentration value but has not yet reached the polluted level and the ecological risk of heavy metals in the sediments also still provides a low ecological risk.