4-2 ions in natural waters by titration of lead salts in the presence of dithizone

Information on water protection zones and riverbanks in the Republic of Uzbekistan:

T/r	The name of the river	Water protection zone		Sh.J. coastal strip
1	Kashkadarya		13106.9	1507.6
2	Zarafshon		29789.3	3710.6
3	Chirchik		9160.6	1440.6
4	Surkhandarya		9208.0	1521.3
5	Koradarya		7540.7	1213.1
6	Norin		4310.7	459.3
general			73116.2	9852.1

I.4.Geochemical pollution of waters
All water retains dissolved gases, ions, undissociated molecules, and colloidal particles. In geochemical classification, it is necessary to determine the taxonomic significance of each component in the water. Academician VI Vernadsky added water to the list of individual minerals and indicated 4,875 types of it, totaling more than 1,500. The scientist divided all the waters into three groups.

• 
  hard water (ice)
  
• 
  gaseous (underground and surface vapors)
  
• 
  in the liquid state.
  

Great attention is paid to the gas content of water. VI Vernadsky listed oxygenated, carbonated, nitrogenous, methane, hydrogen sulfide and hydrogenated waters in this regard. He developed a chemical elemental composition for each type of water. For example, in the 38th family - "rivers" are divided into the following varieties: 95. O - Ca - O 96. O - Na - Ca - S 97. Ordinary rivers, a mixture of № 95 and 96. 98. Water of polar rivers (tundra) O - Ca –C - N 99. Black-brown tropical rivers O - C - N - Ca - Si - Na 100. Boron-bearing rivers O - Na - C - B Vernadsky's classification also includes waters from "radon-storing" oil fields, "black tropical rivers" and others. In 1956, radon was also found in mineral water mined in Tashkent. This classification is a geological-geographical-geochemical classification because it takes into account many factors. Developing VI Vernadsky's views on dissolved gases9, AM Ovchinnikov developed a "hydrogeochemical system of natural waters." According to this system, there are waters in the conditions of oxidizing gases (N2, O2, CO2, etc.), waters in the conditions of reducing gases (CH4, H2S, CO2, N2, etc.) and gases in metamorphic conditions. He carried out his next systematics with the ratio of cations (Na⁺, K⁺, Ca²⁺, Mg²⁺) and the ratio of anions (SO₄^2-,HCO^3-, Cl^-). Most hydrochemists and hydrogeochemists base their water systems on their ionic composition. This classification was proposed by O.A. Alekin.