ASSESSMENT OF WATER QUALITY OF SMALL RIVERS OF THE SYRDARYA BASINS FOR THE SAFE WATER USE
Abstract
Introduction. The aim of the research was to study the water quality of small rivers of the Syr Darya river basin – the Chirchik and Akhangaran rivers, which are the main sources of industrial and economic drinking water supply for the population of the Tashkent region of Uzbekistan. Research methods included laboratory and field studies with the selection of water from reservoirs in accordance with the intended work plan.Sampling of water from rivers was carried out in the established monitoring sites, and the assessment of the quality of river water was carried out for the 2018 seasons in accordance with GOST 951: 2011 " Sources of centralized drinking water supply. Hygiene, technical requirements and selection rules". Results. It was found that the concentrations of ammonia nitrogen, ni-trite nitrogen, and nitrate nitrogen, as well as BOD and COD, exceed the normative values on the Chirchik river sec-tion after the discharge of industrial effluents from the MAXAM-Chirchik joint venture. Downstream in the Akhan-garan river, after the discharge of waste water from the Almalyk mining and metallurgical plant, phenols are deter-mined at the level of 0.003 mg/l in the winter period. Their concentrations in spring and summer increase to 0.004 mg / l, and in autumn they are 0.005 mg/l (MPC 0.001 mg/l). The same dynamics was found in the content of petroleum products in river water: in winter their concentrations are 0.36 mg / l, in spring 0.46 mg/l, in summer 0.53 mg/l and in autumn 0.56 mg/l (MPC 0.3 mg / l). In winter, copper is found in the water of the Akhangaran river at concentrations of 7.2 mg / l, rising to 8.9 mg/l in the spring, to 9.2 mg/l in the summer, with a maximum value in the autumn of 10.2 mg/l (MPC 1.0 mg / l). Similar dynamics are found for zinc and cobalt. The maximum concentrations of iron and molybdenum
in the section of the Akhangaran river below the effluent discharges of the Almalyk mining and metallurgical combine were found in summer and autumn – at the level of 1.3 mg / l (MPC 0.3 mg/l) and 0.71 mg/l (MPC 0.25 mg / l), respectively. Lead in the water of the Akhangaran river was found at 0.03 mg/l in winter and spring, and 0.04 mg/l in summer and autumn (MPC 0.01 mg/l)
