Distribution, Risk Assessment, and Source Identification of Heavy Metals in Surface Sediments of River Soan, Pakistan

Abstract

In the present study, heavy metals concentration and physico‐chemical properties of surface sediments of River Soan, Pakistan, have been investigated. In order to gain insight into the metals distribution, accumulation, and their pollution status, geo‐accumulation index (Igeo) and enrichment factor (EF) were used. The ecological risk for different heavy metals was evaluated using sediment quality guidelines, threshold effect concentration (TEC), and probable effect concentration (PEC). The concentration of heavy metals was relatively high in the post monsoon season as compared to the pre monsoon season. The concentration of Cd was 69% in sediment samples that exceeded the TEC value while none of the metal concentration exceeded PEC. The mean PEC quotient value among different sampling sites ranged between 0.14 and 0.43. The Igeo indicated that surface sediments of River Soan were moderately polluted with Cd (1.42). The EF indicated significant pollution of Cd (12.01) and moderate pollution of Pb (4.05) in sediments, and indicated the influx of Cd and Pb in sediments from anthropogenic sources. Multivariate results indicated an effective role of organic matter, sediment pH, weathering of rocks, and particle size in distribution of metals along with identification of natural and anthropogenic sources of metals. The results can be used for effective management of fresh water resources in Pakistan as well as these findings are applicable to the other rivers of Himalayan region.