Canada to use a Cumulative Risk Assessment Approach for Phthalates
On August 1, Environment Canada and Health Canada proposed to use a cumulative risk assessment (CRA) approach to determine the combined risk to environmental and human health, posed by exposure to multiple phthalates (proposed CRA approach). A CRA approach for phthalates is already embraced by the World Health Organization, the International Program on Chemical Safety, and the U.S. Environmental Protection Agency. Ecological risk assessment would utilize a "sum of internal toxic units" approach, which is based on the presence of phthalates in living organisms and does not require dose-response toxicity data; likewise, human health risk assessment would utilize a hazard index approach that considers relative potency factors and assumes the effects of each phthalate are similar.
Canada's announcement about the CRA approach follows the identification of 14 phthalates as priorities for review under the federal Chemicals Management Plan. According to the Government of Canada, "some [phthalates] have been identified as potentially associated with reproductive and developmental effects; some have a wide range of consumer applications; some are associated with potential ecological effects of concern; and some have been identified as priorities internationally" (Phthalate Substance Grouping notice). Subsequently, Environment Canada and Health Canada added 14 more phthalates for prioritized review, bringing the total to 28 (workshop summary). These 28 phthalates include short-chain phthalate esters (DMP and DEP); medium-chain phthalate esters (DCHP, BCHP, DIBP, DBzP, CHIBP, B84P, BIOP, DMCHP, B79P, DIHepP, DPrP, DBP, BBP, DIOP, DEHP, DnHP and 79P); long-chain phthalate esters (DIDP, DUP, 610P, DnOP, D911P, D911P-2, DTDP, and DIUP); and DINP (long-chain phthalate ester for ecological review; medium-chain phthalate ester for human health review).