Exposure estimation for risk assessment of the phthalate incident in Taiwan

Background: In May 2011, di(2-ethylhexyl) phthalates (DEHP) and, to a lesser extent, di-iso-nonyl phthalate (DiNP) were found to have been illegally used for many years in Taiwan as clouding agents in foods including sports drinks, juice beverages, tea drinks, fruit jam/nectar/jelly, and health or nutrient supplements. Objective: To estimate the DEHP exposure for the study participants for the follow-up epidemiological study and health risk assessment. Methods A total of 347 individuals possibly highly exposed to phthalate-tainted foods participated in the study. Exposure assessment was performed based on the participants' responses to a structured questionnaire, self-report of exposure history, urinary metabolite concentrations, and DEHP concentration information in 2449 food records. A Bayesian statistical approach using Markov chain Monte Carlo simulation was employed to deal with the uncertainties in the DEHP concentrations of the contaminated foods and the participants' likelihood of being exposed. Results: An estimated 37% and 15% of children younger than 12 years old were exposed to DEHP at medium (20-50 μg / kg-bw / day) and high AvDIs (50-100 μg / kg-bw / day), respectively, prior to the episode (9% and 3% in adults, respectively). Moreover, 11% of children and 1% of adults were highly exposed (> 100 μg / kg-bw / day), with a maximum of 414.1 μg / kg-bw / day and 126.4 μg / kg-bw / day, respectively. Conclusions: The phthalate exposure-associated adverse health effects for these participants warrant further investigation. The estimation procedure may be applied to other exposure assessment with various sources of uncertainties.