Ecological and hygienic assessment of the river Kashkadarya and drainage canal water in the intensively irrigated region of Uzbekistan

Abstract

Introduction. Lately, in the agricultural regions of Uzbekistan it is increasingly experiencing a shortage of water suitable not only for irrigation but also for household use, reactivation and tourism. The hypothesis of our study was to investigate whether the level of pollution of the collector-drainage water of the most prominent collector of the Karshi steppe and the Kashkadarya river allowed to use their water for secondary domestic needs. Materials and methods. The following chemical and microbiological indicators were selected as indicators of mineral and organic pollution: carbonate alkalinity, chlorides, sulfates, nitrates, nitrites, ammonium nitrogen, total dissolved phosphorus, coli-index, causative agents of intestinal infections (strains of Shigella and Salmonella). The following parasitic organisms were determined: cysts of Cryptosporidium and Giardia. Results. In the reservoirs of the collector-drainage network of the Kashkadarya region, simultaneously with an increase in the level of organic pollution and eutrophication (biogenic load), the processes of salinization of reservoirs are very active. Limitations. Due to the limited time for transport of samples of the microbiological and chemical analysis to the Tashkent city, as well as lack of qualified staff, the study covered only the lower reaches of the Kashkadarya River, and eight sampling points were selected for analysis on both: the river and the Southern Collector.Conclusion. The microbiological and parasitological analysis results showed that the collector water and the water of the Kashkadarya River are unsuitable for irrigation and create an epidemiological danger for the population.