Study of the dominant modes of formation and variability of potentially toxic element concentrations and their impact on environmental quality

The current research investigates the prevalent spatial distribution types of potentially toxic elements (PTE) - iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), lead (Pb), nickel (Ni), chromium (Cr), and cadmium (Cd) - and their effects on environmental quality and health risk assessment in the cooling water discharge of the nuclear power plant (NPP). A comprehensive geochemical and hydrological assessment was enabled by weekly sampling in 2023 at three strategic locations: pre-discharge (S1), post-discharge (S2) and directly at the cooling water discharge (S3) of the NPP. The investigation revealed that Fe (285.7 ± 44.5 μg/L) and Cu (84.3 ± 51.6 μg/L) had the highest concentrations, with Cu levels significantly increasing at S3 (166.65 ± 51.60 μg/L), likely due to corrosion processes in the NPP cooling system. Strong positive correlations were observed between Cu, total dissolved solids (TDS), and sulphates (SO₄), highlighting anthropogenic sources of pollution. Seasonal variations showed peaks for Zn and Cu during spring and autumn. Environmental quality was assessed using integral water quality pollution indices. Health risk assessment based on the Hazard Quotient for non-carcinogenic risks at location S3 showed local exceedances of the hazard quotient threshold values for Fe, Zn and Pb, but the overall risk level remained low, as evidenced by the values of the integral water quality indices. The application of the Bayesian Model Averaging technique has enabled the identification of pH, total suspended solids, and nutrients as the dominant predictors of PTE behaviour. These findings emphasize the non-radiological impacts of NPP discharges and underscore the necessity for integrated environmental and public health monitoring frameworks.