PROBIT ANALYSIS FOR Cd, Pb, Cu, Zn PHYTOTOXICITY ASSESSMENT

The aim of investigation was to develop a new approach in Cd, Zn, Cu, Pb phytotoxicity assessing. This approach provided the probit analysis using. Methods included probit analysis, thin layer chromatography, statistical methods (calculation of the least significant difference, correlation analysis). We applied «doze-effect» model to obtain the ranking of the metals according to their phytotoxicity in spring barley field. We offered to estimate the phytotoxicity by PhLD50 index. Research results were: graphic formalization of "dose-effect" dependence and calculation of phytotoxic doses (PhLD50 and PhLD95) for Cd, Cu, Pb, Zn in polluted soil. According to PhLD50 value we conducted a comparative assessment of Cd, Cu, Pb, Zn phytotoxicity relatively to spring barley. According to PhLD50 value metals could be ranked: Cd> Cu> Pb> Zn. The most toxic metal was Cd. PhLD values, on which the estimation of metals phytotoxicity, were: Cd – 50, Cu –129, Pb –537, Zn –603 mg / kg mobile forms in turf-podzol sandy loam soil. Our findings are relevant to estimating the metal hazard and controlling the condition of the crop growth.