Assessment of heavy metals contamination in surface sediments of Sabratha, Northwest Libya

Abstract

In order to assess the effect of sewage on surface sediments of Sabratha area, seven heavy metals were analyzed by Atomic Absorption Spectrophotometer in 40 sediment samples collected from the vicinity area of a sewage station. Environmental pollution indicators as an enrichment factor (EF), potential contamination index (Cp), soil pollution index (SPI), potential ecological risk index (PERI), correlation coefficient, and cluster analysis (Pearson’s method) were used. The results illustrated that the studied sediments are extremely severe with Cd (EF > 50; Cp > 3; SPI > 3; 160 ≤ PERI 320) and severe enrichment with Pb and Co (EF = 10–25; 1 < SPI ≤ 3). The potential sources of metal pollution in the study area are anthropogenic sources such as sewage, traffic exhaust, agricultural activities, and landfills. These results are very distinct in the samples near to the sewage station, indicating that they may be the most significant reason for the increasing metal concentrations in the study area. These results show that the average concentration of Cd and Pb is higher than the permissible level relative to those recorded in many world localities.