Heavy metals as criteria of health and ecological well-being of the urban environment.

The study of the content of Pb, Cd, Ni, Zn, Mn, Cr, and Cu in biological media (the hair) of children living in the zones of the city of Kazan with different pollution levels was carried out. The identification of the zones in the city of Kazan was performed on the basis of the snow cover and soils pollution with heavy metals, which are natural accumulators of chemical substances and heavy metals (HM). Statistically significant differences (р < 0.01) in the content of certain metals in the hair, lead and cadmium in particular, were revealed in children living in the technologically polluted zone (Teplocontrol). Microelement composition of the hair in children with respiratory diseases (RD) varied widely in the content of lead (р < 0.05), and a statistically significantly lower level of zinc (р < 0.01) and copper (р < 0.05) compared with all the rest groups of children was determined in genitourinary diseases (GUD). However, relatively high values of toxic elements in the control zone show that the ecological status of the city and region is instable, and implies additional measures of the environmental monitoring and activities on chemical safety in certain city zones.