Problems of risk assessment to public health in megacities (by example of some districts of St. Petersburg,Russia)

The opportunities and problems to use the known methods to health risk assessment based on the dependence of the «dose — effect» for threshold substances are discussed. The necessity to develop an adequate method to estimate health risk for threshold substances taking into account nonlinear-linear relationship between dose and response to it, the chemical properties of substances, sex-age parameters of the individuals are considered.