Hydrochemical composition and potentially toxic elements in the Kyrgyzstan portion of the transboundary Chu-Talas river basin, Central Asia

Abstract

Water chemistry and the assessment of health risks of potentially toxic elements have important research significance for water resource utilization and human health. However, not enough attention has been paid to the study of surface water environments in many parts of Central Asia. Sixty water samples were collected from the transboundary river basin of Chu-Talas during periods of high and low river flow, and the hydrochemical composition, including major ions and potentially toxic elements (Zn, Pb, Cu, Cr, and As), was used to determine the status of irrigation suitability and risks to human health. The results suggest that major ions in river water throughout the entire basin are mainly affected by water–rock interactions, resulting in the dissolution and weathering of carbonate and silicate rocks. The concentrations of major ions change to some extent with different hydrological periods; however, the hydrochemical type of calcium carbonate remains unchanged. Based on the water-quality assessment, river water in the basin is classified as excellent/good for irrigation. The relationship between potentially toxic elements (Zn, Pb, Cu, Cr, and As) and major ions is basically the same between periods of high and low river flow. There are significant differences between the sources of potentially toxic elements (Zn, Pb, Cu, and As) and major ions; however, Cr may share the same rock source as major ions. The risk assessment revealed low non-carcinogenic and carcinogenic risks for human health; however, the maximum carcinogenic risk for As exceeded the allowable value, which requires further consideration. These results provide a scientific basis for the management of agricultural irrigation uses and also infill existing gaps regarding the hydrochemical composition in the Chu-Talas river basin, Central Asia.

Water Quality for Agricultural Irrigation and Aquatic Arsenic Health Risk in the Altay and Tianshan Mountains, Central Asia

“…The charge balance error percentage (CBE) [36] was between 0.4 and 4.5, which is less than ±5%. After the water samples were filtered through a 0.45 µm microporous membrane, 200 mL was acidified with a 0.6 mL nitric acid solution (volume ratio 1:1), and the As content in the solution was analyzed with an Agilent 8800 inductively coupled plasma mass spectrometer (Agilent Technologies, Santa Clara, CA, USA) [7,37].…”

“…The river becomes the link between the mountain system and the oasis system and is the foundation for ecological construction and economic development in arid areas. The composition of major ions in river water is one of the most important indicators of river water quality and contains important environmental information on things, such as climate, bedrock type, and human activity in the watershed [7], and it is the most basic indicator for irrigation evaluation and drinking-water-safety evaluation [8,9]. In recent years, scholars have paid much attention to the water-resource and environmental problems in the western part of the Tianshan [10,11] and Altay [12,13] Mountains (Mts.…”

Spatiotemporal Distributions of Fluoride and Arsenic in Rivers with the Role of Mining Industry and Related Human Health Risk Assessments in Kyrgyzstan

“…At present, some scholars have analyzed the arsenic or fluoride concentrations in some rivers of Kyrgyzstan, such as the Shu River, Shor-Koo River, and Aksu River (Solodukhin et al 2016), surface water in Mailuu Suu town (Alvarado et al 2014;Aparin et al 2012) and the Naryn River (Ma et al 2019). Simultaneously, some scholars have conducted human health risk assessments for potential toxic elements in the rivers of Kyrgyzstan and have found that the arsenic levels in the rivers of the Issyk-Kul Basin (Liu et al 2020) and the transboundary river of the Chu-Talas River in Kyrgyzstan (Ma et al 2020) were harmful to human health. However, most of the research objects were limited to a single river, watershed or area.…”

Spatiotemporal Distributions of Fluorine and Arsenic in Rivers With the Role of Mining Industry and Related Human Health Risk Assessments in Kyrgyzstan

“…Simultaneously, some scholars have conducted human health risk assessments for potential toxic elements in the rivers of Kyrgyzstan and have found that the arsenic levels in the rivers of the Issyk−Kul Basin 17 and the transboundary river of the Chu-Talas River in Kyrgyzstan 18 were harmful to human health. However, the above research objects were generally limited to a single river, watershed or prefecture, and the concentrations and distributions of fluorine and arsenic in the rivers of Kyrgyzstan, spatiotemporal distribution characteristics of fluorine and arsenic in river water, influencing factors of spatial distributions of fluorine and arsenic in river waters, whether fluorine and arsenic simultaneously exceeded the established limits, and the health risk of both to human health are still unclear.…”