Water Elemental Composition and Toxicity in Kazakhstan’s Transboundary Rivers

Abstract

The article describes the monitoring results of the content of chemical elements (As, Cr, B, Ba, Li, Mo, Pb, Sb, Sr, U, and Cr) in the water of transboundary rivers of Kazakhstan (Shagan, Ural (kaz. Zhayik), Ilek, Tobol, Ayat, Irtysh (kaz. Yertys), Emel, Ili (kaz. Ile), Tekes, Shu, Kara-Balta, Talas, and Syr Darya) conducted in 2020. The toxic element concentrations underwent comparison with background levels (Clark[e] numbers) and maximum permissible concentrations (MPC), with sub-sequent calculation of the total toxicity index (KHL). The study showed that practically all the inves-tigated rivers were subject to contamination, with uranium and lithium as the greatest contributors to surface water toxicity. The rivers in Southern and South-Eastern Kazakhstan – namely, the Kara-Balta, Syr Darya and Shu – were found to be most exposed. For instance, the KHL of the Kara-Balta River water exceeded the permissible threshold by over 5.9 times. The lowest KHL value (<1) corre-sponded to the Yertys and Ile Rivers. The research made it possible to identify the toxicity of trans-boundary waters flowing into the territory of Kazakhstan, as well as provided basis for further in-vestigation to identify pollution sources.

Mutagenic activity of water samples from Kaskelen River (Kazakhstan) on plant test systems

“…The irrigation of agricultural land with river water has been identified as a cause for the presence of various chemical substances in plants, which exhibit toxic and genotoxic activities [5,6]. A significant proportion of Kazakhstan rivers are continuously affected by pollution from heavy metals and organic substances [7][8][9]. The intensification of industrialization, urbanization, agricultural development, the growth of domestic tourism and the unregulated exploitation of natural resources lead to a deterioration in water quality and a change in the characteristics and properties of various ecosystems, including aquatic ecosystems [10].…”

Occurrence of Radionuclides and Hazardous Elements in the Transboundary River Basin Kyrgyzstan–Kazakhstan

“…The study of water quality in such areas is important for ensuring food security because water pollution can lead to the contamination of plant products and affect human health [16,17]. A number of studies [18][19][20][21][22][23] have been published based on the results of the governmental monitoring of the main transboundary rivers in Kazakhstan. These publications have highlighted the problems of pollution with hazardous elements of soils and bottom sediments of the main transboundary rivers between Kyrgyzstan and Kazakhstan.…”