Zerafshan River

As an example, we will consider the formation of nitrate biogeochemical provinces in the Desert region of biosphere in Zerafshan river watershed that occupies most of the Samarkand administrative region of Uzbekistan. This is an agricultural area with irrigation production of cotton and some other crops like cereals, vegetables and fruits. The natural biogeochemical provinces are characterized by iodine, copper, and zinc deficiency and lithium excess. 

The accumulation of pesticides is connected with their long-term application at heavy rates, 15 kg/haon average during the 1970-1980s. The elevated concentrations of PCB are related to irrigation by polluted waters from the Zerafshan River (Galiulin... 

We can see that at TSS content of natural water up to 50(X) ppm, the boron content is 1 ppm, at TSS content up to 50,000 ppm, B content is 15 ppm. The increasing content of boron in the Aktubisk administration region, Kazakhstan, was monitored in 37.2% of surface water bodies and 55.5% of wells. The average content of boron in the large rivers (Amu-Daria and Zerafshan) is 0.15 ppm. and it is connected with the formation of water chemical composition outside of these arid regions. 

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