Water Chemistry, Source Identification, and Health Risk Assessment in Surface Water of the Ural River

Health risk assessment of the surface water of the Ural River draws specific interest as the river has been providing recreational sites for many citizens. Therefore, the exposure assessment scenario for most of the investigated sampling sites was based on dermal contact during swimming, with rare cases of direct drinking of the Shagan River water. Results from the swimming path demonstrated that the noncarcinogenic risks were insignificant. In contrast, carcinogenic risks exceeded the threshold values and could have an accumulative effect on the population's health, with Ni having the most significant contribution (up to 80% of the total cancer risk). Cancer risks remained within the range of 5.39 x 10(-7)-5.22 x 10(-5). SO4, Cl, and Ca were the dominant ions due to natural processes in the water, such as weathering and crystallization. In contrast, principal component analysis (PCA) showed that local enterprises, such as metalworking plants and mines, were potential sources of heavy metal contamination of the river. The study could raise awareness about potential hazards that heavy metals may cause to the health of Kazakhstan citizens, and in the future, this study's results can be applied to introducing stricter environmental standards for industrial heavy metal emissions.