[Pollution and human exposure: proposal of criteria for meeting the WHO recommendations in the matter of risk reduction related to the environment].

Risk assessment methods do not refer to the dynamical processes at the back of observed values of parameters, when relating an effect to one evaluation of doses, or bio-indicator values to external contamination levels. This results in decreasing responses of the human organism as a function of increasing exposure levels. On the contrary, the ecotoxicological approach, applied to the case of lead, shows that a first order kinetics holds until blood lead of 80 micrograms/dl blood, either for the relation between tooth and blood lead, or for this between blood lead and the flux of lead absorbed daily (micrograms/day). Then, the max. admissible concentrations for various sources of Pb should be lowered strongly, for maintaining the Pb body burden below limit values. The method is proposed for application to a series of other pollutants, and for risk reevaluation.