Radiation and Hydro-Chemical Investigation and Monitoring of Transboundary Rivers of Kazakhstan

Distribution Characteristics and Assessment of Heavy Metals in the Surface Water of the Syr Darya River, Kazakhstan

“…The part is 1400 km in length, and the drainage area is 21.84×10 4 km 2 . It flows through southern Kazakhstan and Kyzylorda and is the main freshwater resource of South Kazakhstan [18]. In the territory of Kazakhstan, the largest tributary is the Arys River, which flows down from the southwestern Kalaou Ridge; the river thereafter has no direct tributary flow into the Aral Sea and forms a large delta in the town of Kazaritsi.…”

“…Overall, the concentrations of Zn, Pb and Mn in the water samples showed a clear decreasing trend along the river, and there were 15 water samples in which no Pb was detected. The high concentrations of the heavy metals Zn, Pb and Mn concentrated near the Arys River tributary of the Syr Darya River may be related to the Arys River itself, which receives sewage water from industrial activities in the town of Shymkent and other residential areas upstream [16], and may also receive pollutants from the mining, metallurgy and chemical industries in upstream countries [18]. Some high concentrations of Cu were observed in water samples near the Arys River, which could be due to the accumulation of sewage water from industrial activities in the town of Shymkent and the mineral deposits surrounding the Arys River, and another high concentration of Cu near the Aral Sea may be due to the gradual accumulation of upstream pollution.…”

“…Previous studies on heavy metal pollution in surface water in the study area have simply described the state of heavy metals in the region [16,18,19], but there is no detailed evaluation of the possible harm to the environment and human body caused by current heavymetal concentrations. To better understand the potential hazards of heavy metals in surface waters in the study area, this study used an analysis of the mathematical statistics of heavy metals in water samples, the strictest maximum-permissible-concentration standards of the fishery industry and the heavy metal pollution indexto evaluate the influence of heavy metals on the aquatic environment, and the generally used United States Environmental Protection Agency (U.S. EPA)recommended human health risk assessment models to evaluate the degree of harm that heavy metals may pose to the environment and the human body.…”