Prediction of sediment quality based on the concentration of heavy metals Cu, Zn, and Ni in Jakarta Bay using the index analysis approach

Abstract

The purpose of this study was to predict the concentration of heavy metals Cu, Zn, and Ni in sediments and to predict the sediment quality based on an index analysis approach (contamination factors, geo accumulation index, pollution load index, ecological risk index, and potential ecological risks index). The sediment sample taken by using a sediment grab in Jakarta Bay. Heavy metal content measured by using Atomic Absorption Spectrophotometer (AAS). The results showed that the Cu range from 14.79 to 55.36 µg.g-1 with an average of 33.178 µg.g-1, Zn range from 82.05 to 441.91 µg.g-1 with an average of 197.484 µg.g-1 and Ni range from 16.47 to 22.09 µg.g-1 with an average of 19.328 µg.g-1. The mean levels of Zn and Cu were still lower than the threshold value of sediment quality, i.e., 108 µg.g-1 for Cu, 271 µg.g-1 for Zn, while for Ni is higher, ie, 16 µg.g-1. The results of the index analysis showed that the average value of contamination factor (CF) of Cu, Zn, and Ni were 1.614, 2.018, Ni -0.138 respectively (1 < CF < 3, moderate contamination), the average of geo accumulation index values of Cu, Zn, and Ni were -0.136, -1.010, -0.138 ((Igeo < 0, unpolluted) respectively. The average Pollution Load Index value (PLI) is 1.637 (PLI > 1); based on the PLI index, sediments are categorized as polluted by Cu, Zn, and Ni. Based on ecological risk index (Er) and potential ecological risk index (RI), sediment includes low risk ecology (Er < 40) and low potential risk ecology (RI<150).