Health effects classification and its role in the derivation of minimal risk levels: renal effects.

The Agency for Toxic Substances and Disease Registry (ATSDR) derives minimal risk levels (MRLs) for priority hazardous substances. MRLs are health guidance values intended to serve as screening levels for health assessors to select contaminants of concern and to assess potential health effects at hazardous waste sites and areas affected by unplanned releases. Current MRLs are published in ATSDR toxicological profiles and are listed at the ATSDR website at . To date, ATSDR has derived 125 inhalation MRLs, 207 oral MRLs, and eight external radiation MRLs; 19 MRLs are based on renal effects. This article reports on endpoints used to derive the MRLs. It also presents the ranking of effects into less serious and serious categories as described in ATSDR's Guidance for Developing Toxicological Profiles.