Assessments of heavy metal contaminations of surface water and sediment of Pülümür Stream (Türkiye)

The primary considerations within aquatic ecosystems are water and sediment quality, rendering it imperative to assess their concentrations, pollution levels, origins, and ecological hazards. In this study, heavy metal concentrations in surface waters and sediments of the Pülümür Stream were investigated to assess the level, distribution, source of pollution and the associated human risks. Water and sediment samples from the river were collected monthly from February 2021 to January 2022 and examined using the Inductively Coupled Plasma Mass Spectrometry (ICP– MS) technique. Metal concentrations in the sediment followed a decreasing or derivative sequence of Fe > Al > Mn > Ni > Cr > Zn > Cu > Pb > As >Cd > Hg. The ecological indices of the stream water have low degrees of contamination by heavy metals. Igeo and EF showed that most of the sites are moderately to highly polluted due to Ni, and Cr, while PLI and PERI showed a progressive deterioration of the environment at site 9. Moreover, the modified hazard quotient (mHQ) indicates low ecological risk for Cu, Pb, Zn, Cd, Hg metals, while Ni, As and Cr reach high pollution at sediment sites. Pearson correlation analysis revealed that the presence of Zn, Cu, Pb, Hg, and Mn metals in the sediment analysis has a lithogenic source, and As, Ni, Cd, and Cr accumulate due to human activities, mainly domestic and agricultural irrigation wastes and mining wastes, all of which affect the aquatic environment. According to this study, more attention should be paid to the comprehensive monitoring of metals in the water and sediment for both aquatic biota and human risk of the Pülümür River.