Derivation of ATSDR Non-Cancer CVs
CV= comparison value
EMEG = environmental media evaluation guide
MRL = minimal risk level
RfC = reference concentration
RfD = reference dose
RMEG = reference dose media evaluation guide
This figure shows how ATSDR derives its non-cancer CVs. ATSDR starts with contaminant-specific non-cancer health guidelines. These include health guidelines for chronic ingestion (MRLs and RfDs) or inhalation (MRLs and RfCs) or for intermediate or acute ingestion or inhalation (MRLs).
For ingestion, ATSDR then applies default, protective exposure assumptions to the oral MRLs and RfDs (body weight and intake rate).
ATSDR uses the inhalation guidelines directly. These include MRLs (EMEGs as CVs) and RfCs (RMEGs as CVs).
This process is how ATSDR derives contaminant- and media-specific non-cancer CVs, including chronic, intermediate, and acute EMEGs and chronic RMEGs.