A framework for an alternatives assessment dashboard for evaluating chemical alternatives applied to flame retardants for electronic applications

Abstract

The goal of alternatives assessment (AA) is to facilitate a comparison of alternatives to a chemical of concern, resulting in the identification of safer alternatives. A two stage methodology for comparing chemical alternatives was developed. In the first stage, alternatives are compared using a variety of human health effects, ecotoxicity, and physicochemical properties. Hazard profiles are completed using a variety of online sources and quantitative structure activity relationship models. In the second stage, alternatives are evaluated utilizing an exposure/risk assessment over the entire life cycle. Exposure values are calculated using screening-level near-field and far-field exposure models. The second stage allows one to more accurately compare potential exposure to each alternative and consider additional factors that may not be obvious from separate binned persistence, bioaccumulation, and toxicity scores. The methodology was utilized to compare phosphate-based alternatives for decabromodiphenyl ether (decaBDE) in electronics applications.

Combining In Silico Tools with Multicriteria Analysis for Alternatives Assessment of Hazardous Chemicals: Accounting for the Transformation Products of decaBDE and Its Alternatives

“…Pentabromodiphenyl ethers (pentaBDE) did not have a high occurrence potential through our approach as a transformation product for decaBDE, despite this being a major consideration in decaBDE hazard and risk assessments. 8 , 13 Part of the explanation for this is the lack of predictive tools for photodegradation since pentaBDE has been considered as an important photodegradation product of decaBDE 7 , 8 , 61 , 62 and also that this would be a transformation product after five subsequent debromination reactions. However, because pentaBDE is considered a critical transformation product of decaBDE, it was also included herein for further hazard assessment.…”

“…Additionally, organophosphate flame retardants (OPFRs) were considered, even though they were not amongst the least hazardous alternatives, because they are an important class of flame retardants considered in a similar study. 13 Here two OPFRs were included to represent halogenated and nonhalogenated OPFRs, respectively: tris(tribromoneopentyl) phosphate (TTBNPP) and triphenyl phosphate (TPHP). Collectively, these alternatives cover a broad array of hazard criteria and substance classes: brominated flame retardants, brominated OPFRs, halogen-free OPFRs, and melamine.…”

“…9 , 10 The importance of including transformation products is often pointed out in chemical hazard assessments used in alternatives assessment frameworks like GreenScreen, 11 U.S. Environmental Protection Agency (EPA) Design for Environment (DfE) Program, 12 and recently by Martin. 13 However, this remains a difficult task, as many of the chemicals considered in alternatives assessments are novel compounds that have been subjected to a few experimental investigations themselves. Experimental data on their transformation products are even more scarce.…”

“…For example, GreenScreen 11 suggests the use of models provided by the OECD QSAR Toolbox 15 for predicting chemical transformation when there are no experimental data available. Martin 13 used the Chemical Transformation Simulator (CTS) 16 , 17 provided by USEPA to predict biotransformation products for case chemicals. There is a range of other in silico tools available that have been used for the prediction of transformations products for chemical risk assessment of organic chemicals, including commercial tools such as Metasite, 18 Stardrop, 19 Zeneth, 20 and Meteor Nexus, 21 as well as open-source tools such as BioTransformer 22 and the EAWAG-biocatalysis/biodegradation database pathway prediction system (EAWAG-BBD/PPS).…”

“… 13 , 24 These challenges all contribute to there being very few published alternatives assessment case studies that take transformation products into consideration. One exception to this was Martin, 13 which concerns decaBDE as well as three proposed organophosphate-based alternative flame retardants. In that study, transformation products predicted by CTS 16 , 17 were considered and hazard information was given for each of the parent compounds and transformation products, though without providing a hazard ranking for alternative selection.…”