Based on our understanding of homeostatic and adaptive mechanisms, systemic toxicity is treated as if there is an identifiable exposure threshold (both for the individual and for populations) below which there are no observable adverse effects. In addition, chemicals that cause cancer and gene mutations also commonly evoke other toxic effects (i.e., systemic toxicity). (In this document the term 'systemic toxicity' refers to an effect other than carcinogenicity or mutagenicity induced by a toxic chemical.)Д¬hemicals that give rise to toxic endpoints other than cancer and gene mutations are often referred to as 'systemic toxicants' because of their effects on the function of various organ systems. EPA, 1987), which describe the Agency's approach to risk assessment in other areas, specifically carcinogenicity, mutagenicity, developmental toxicity, exposure, and chemical mixtures. By outlining principles and concepts that guide EPA risk assessment for such systemic effects the paper complements the new risk assessment guidelines (U.S. EPA) principal approach to and rationale for assessing risk for health effects other than cancer and gene mutations from chronic chemical exposure. REFERENCE DOSE (RfD): DESCRIPTION AND USE IN HEALTH RISK ASSESSMENTS HYPOTHETICAL, SIMPLIFIED EXAMPLE OF DETERMINING AND USING RfDДЎ. EPA ASSESSMENT OF RISKS ASSOCIATED WITH SYSTEMIC TOXICITY SOME DIFFICULTIES IN UTILIZING THE TRADITIONAL APPROACH TRADITIONAL APPROACH TO ASSESSING SYSTEMIC TOXICITY

List of i doser doses and effects