What I heard at the 2023 Society of Risk Analysis (SRA) conference in Washington, D.C.

TSCA and Cumulative Risk Assessment (CRA) of Phthalates

Kelsey Hendrixson (Noblis) presented a new draft approach, the TSCA and Cumulative Risk Assessment (CRA) of Phthalates (EPA-HQ-OPPT-2022-0918-0009), to request comprehensive and cumulative risk assessments for phthalates. Until now, the EPA has approached TSCA section 6 risk evaluations by looking at the risk posed by a single chemical substance under the conditions of use. For the EPA believes that the best approach to evaluate risk to human health may be to look at the combined risk to health from 7 phthalates (dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisobutyl phthalate (DIBP), dicyclohexyl phthalate (DCHP), di-isodecyl phthalate (DIDP), and diisononyl phthalate (DINP)) with similar effects simultaneously. The 7 phthalates are grouped into a single class based on physicochemical properties, exposure pattern overlap, similar or same mode of action and toxicological hazard profiles.

If this new approach by the EPA moves forward to implementation, it could require manufacturers to consider exposures to multiple phthalates that have similar or the same health effects as the specific chemical undergoing the EPA risk evaluation.

Polymer Reverse Engineering to Design Safer Molecules

A novel collaborative and inclusive approach was presented by Margaret MacDonell (Argonne National Laboratory) that incorporates exposure and hazard in the design of safer polymers. The safer polymer approach uses a reverse engineering approach allowing for incorporation of environmental reference frameworks that would enable developers at the bench to consider post use fate at the outset, as part of their plastics design. Current issues are that many used plastics are discarded, and may “leak” into the environment, causing concern that these wastes could be persistent and have ecological and health implications.

The current situation is that product design largely focuses on use, key data is limited and scattered and therefore lacks a systematic approach for considering polymers after life up front. Begging the question is a need for environmentally benign plastics.

 

Ashish Jachak, Ph.D., principal toxicologist at RHP Risk Management Inc.

 

 

 

 

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