Riparian soil toxicity caused by sediment metal transport, seasonal changes and ecological risk assessments for the watershed

Abstract

Abstract Accumulation of the pollutants in the sediment along the surface water may negatively affect on the riparian zones and ecological risk dimension. In order to reveal this problem, in the present study, detailed metal monitoring of sediments and riparian soils was performed seasonally with ICP-OES analysis. Pollution levels, changes, and potential sources were determined statistically. Ecological statuses are detailed. Contamination factor (CF), Enrichment factor (EF), Index of geo-accumulation (Igeo), pollution index (PI), and modified pollution index (MPI) potential and modified ecological risk indexes were analyzed. Although no significant seasonal differences were observed, almost all metals in the sediments and riparian soils spatially differed. Cr (11.4 to 136), Co (7.7 to 21.52), Cu (11.4 to 76.6), and Ni (14.06 to 128.2) as mg/kg from the upstream to the downstream increased significantly and gradually accumulated. The riskiest metals in the sediment and riparian soil in terms of basin river health are Cu, Co, Ni. Risk values were found heavily polluted (PI > 3 and MPI > 10), and the risk indexes (RI) are well above the "desired environment without the risk". RI was found to be more than 50, and modified risk indices exceeded 200 at many points. The transport of pollution in surface water has been revealed in the sediment and adverse effects on the riparian zone and ecological system. Considering sediment and riparian soil together, pollutant-based and holistic ecological risk assessments are necessary to determine river health.