Derivation of Biomonitoring Equivalents for di(2-ethylhexyl)phthalate (CAS No. 117-81-7)

Abstract

Recent efforts worldwide have resulted in a growing database of measured concentrations of chemicals in blood and urine samples taken from the general population. However, few tools exist to assist in the interpretation of the measured values in a health risk context. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of an environmental chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline, and are derived by integrating available data on pharmacokinetics with existing chemical risk assessments. This study reviews available health-based exposure guidance values for di(2-ethylhexyl)phthalate (DEHP) from Health Canada, the United States Environmental Protection Agency (U.S. EPA), the Agency for Toxic Substances and Disease Registry (ATSDR), the European Chemicals Bureau (ECB), and the European Food Safety Authority (EFSA). BE values corresponding to the oral reference dose (RfD), minimal risk level (MRL) or tolerable daily intake (TDI) estimates from these agencies were derived based on data on excretion fractions of key urinary metabolites. BE values based on the sum of three, four, and five of the most predominant and commonly-measured metabolites of DEHP are presented. These values may be used as screening tools for evaluation of biomonitoring data for DEHP metabolites in the context of existing risk assessments and for prioritization of the potential need for additional risk assessment efforts for DEHP relative to other chemicals.