Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

Table 8.2. 
Classification of substances and ions dissolved in water, 
depending on their concentration 
Concentration levels of substances 
dissolved in the water
Characteristic ions and dissolved 
substances 
Predominant components  
(more than 5 mg/l)
HCO
3
–
, Ca
2+
, Mg
2+
, Si, Na
+
, Cl
–
, SO
4
2–
, CO
2
, 
O
2
, organic substances
Macro-components  
(concentration from 0.01 to 10 mg/l) 
CO
3
2–
, Fe, P, NH
4
+
, NO
3
–
, NO
2
–
, K
+
, F
–
, H
2
S
Microelements 
(concentration <0.01 mg/l)
Al, As, Ba, Be, Bi, Br, Cd, Ce, Cr, Co, Cu, 
Ga, Ge, Au, In, I, La, Pb, Li, Mn, Mo, Ni, 
Pt, Ra, Se, Ag, Sn, W, U, Zn
One of the most important characteristics of natural waters is 
a substantial variability of different inorganic ion concentration. If 
the waters of the seas and oceans are dominated by sulphate ions, 
in fresh water higher concentrations of hydrogen carbonate ions 
predominate.