Pollution level, environmental risk, and source of potentially toxic elements in the sediment of Çoruh River (Bayburt, NE Turkey)

The aim of the present study was to define potentially toxic element (PTE) concentrations, their pollution levels, their ecological risks, and the human health risks of Çoruh River sediments in Bayburt (NE Turkey). The sediment samples were analyzed through inductively coupled plasma mass spectroscopy (ICP-MS). The concentrations (mg/kg) of Ni, Cu, Zn, As, Pb, Cr, and Hg varied within 243.6–1134.3, 23.7–178.6, 33.0–52.0, 8.5–38.8, 4.0–7.7, 1.27–7.17, and 0.02–0.10 in the sediments, respectively. According to various geochemical indices, such as the geo-accumulation index, pollution index, pollution load index, and enrichment factor, the sediments were unpolluted by Cr, Zn, Pb, and Hg, and these elements were not enriched in the sediments. By contrast, the sediments were generally moderately polluted—very strongly polluted by Cu, As, and Ni, and these elements were moderately enriched—extremely enriched in the sediments. The results of the ecological risk factor for Ni, As, Cu, and Hg ranged from a low to a high potential ecological risk (RI). The RI values revealed that the investigated area was in a high-risk condition because the corresponding RI value was greater than 150. The outcomes of the modified hazardous quotients demonstrated that Ni, As, and Cu would pose an important health risk if humans were exposed to the sediments and could be hazardous to aquatic animals in Çoruh River. The hazard quotient for ingestion and the hazard index of As for children more than a year old in the high-intensity residential area indicated that As would pose an important health risk if children were exposed to the sediments. Pearson’s correlation matrix and principal component analyses showed that the accumulation of PTEs in Çoruh River’s sediments was related to anthropogenic and geological sources.