Relative risk assessment of Bis (2-ethylhexyl) phthalate and alternative plasticizers: Application of consumer exposure tools and damage functions

抄録

This study evaluated the effects of reducing the exposure concentration and the human health damage of alternative plasticizers to di(2-ethylhexyl) phthalate (DEHP) by a novel relative and quantitative risk assessment framework. The framework combines semivolatile organic compounds (SVOC) consumer exposure tools and damage functions. The used exposure tools were the consumer exposure models (CEM) of the US Environmental Protection Agency (US EPA) and DustEx of the Dutch National Institute for Public Health and the Environment (RIVM). These were used in the chemical substance management systems of the Toxic Substances Control Act (TSCA) and the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Concerning plasticizers, we determined the rational values for the main parameters and estimation accuracy which have not been informed sufficiently to users. We also identified the key parameters for operating the exposure tools. The indoor concentrations of DEHP were predicted using a simple box model, and the estimation accuracies of CEM and DustEx were evaluated by comparing predicted DEHP concentrations with actual measured values. For the DEHP concentration in house dust, both CEM and DustEx had an estimation accuracy of Factor 3⁻¹–3. In particular, in the region of LogK_oa <12, DustEx tended to provide higher estimations of the dust phase concentration compared with CEM. The material/air partition coefficient K_ma was the most sensitive and crucial parameter for both exposure tools. Compared with DEHP, the predictions of both exposure tools showed that the alternative plasticizers had lower exposure concentrations of 86.8%–4.5% in air and 75.5%–4.4% in dust. In addition, the damage functions for nonphthalates were newly determined, and the human health damage amount was calculated by multiplying the determined damage function by the estimated exposure concentration. The total amount of human health damage of alternative plasticizers was 59⁻¹–655⁻¹ compared with DEHP, indicating that the nonphthalate di(2-ethylhexyl) terephthalate (DEHT) had the highest risk reduction effect.