Heavy Metals and Related Human Health Risk Assessment for River Waters in the Issyk-Kul Basin, Kyrgyzstan, Central Asia.

Wen Liu,Yaoming Li,Jilili Abuduwaili,Salamat Abdyzhapar Uulu,Long Ma

doi:10.3390/ijerph17103506

Abstract

The water resources of Central Asia play an important role in maintaining the fragile balance of ecosystems and the sustainable development of human society. However, the lack of research on the heavy metals in river waters has a far−reaching influence on public health and the sustainable development in Central Asia. In order to reveal the possible sources of the heavy metals and to assess the associated human health risks, thirty−eight water samples were collected from the rivers of the Issyk−Kul Basin during the period with low river flow (May) and the period with high river flow (July and August), and the hydrochemical compositions and major ions of heavy metals were analyzed. No changes in hydrochemical facies were observed between the two periods and the river water type was calcium bicarbonate. Carbonate dissolution and silicate weathering controlled the variation of cations and anions in river waters from the Issyk−Kul Basin. There were some differences in the sources of heavy metals in water bodies between the two periods. During the period with low river flow, heavy metals (Cr) were closely clustered with major ions, indicating that they were mainly affected by water–rock interactions. During the period with high river flow, all heavy metals studied in this paper had different sources of major ions, and the heavy metals maybe influenced by human activities. From the human health risk assessment, the hazard quotients for all samples were less than 1, reflecting that there was no noncarcinogenic risk in the river waters of the Issyk−Kul Basin during the two sampling periods. However, the water samples with carcinogenic risk of arsenic exceeding the threshold (10−4) accounted for 21.1% of the total, indicating that there were some certain carcinogenic hazards for human health via water drinking with direct oral ingestion. The results are of certain significance for the utilization and protection of water resources in the basin as well as the protection of public health.

Highlights

The water resources of Central Asia play an important role in maintaining the fragile balance of ecosystems and the sustainable development of human society [1,2,3]
For the river waters of the Issyk−Kul Basin shown in Tables 2 and 3, the concentration of Zn varied between 0.634 and 9.75 μg L−1, with a mean of 5.43 μg L−1, during the period with low river flow, and the concentration of Zn varied between 0.359 and 26.3 μg L−1, with a mean of 9.60 μg L−1, during the period with high river flow
This suggests that river samples plotted in the dominant area are dominated by rock, which suggests that major ions in river water from the Issyk−Kul Basin are mainly controlled by the process of water–rock interactions

Summary

Introduction

The water resources of Central Asia play an important role in maintaining the fragile balance of ecosystems and the sustainable development of human society [1,2,3]. Public Health 2020, 17, 3506; doi:10.3390/ijerph17103506 www.mdpi.com/journal/ijerph

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Conclusion