You are here:
Temporal trends of cumulative risks to phthalate mixtures in the United States from 2005 to 2014
Citation:
Reyes, J. AND P. Price. Temporal trends of cumulative risks to phthalate mixtures in the United States from 2005 to 2014. 2018 SOT Annual Meeting and ToxExpo, San Antonio, TX, March 11 - 15, 2018.
Impact/Purpose:
This poster presents findings on significant secular changes in cumulative phthalate exposures over the last 10 years. The abstract also demonstrates how information on exposure can be used to guide the assessment of cumulative risks for groups of chemicals.
Description:
Phthalates are used in a wide range of consumer goods resulting in widespread exposures among the general population. Exposures to specific phthalates are expected to vary over time with changes in the patterns of phthalate use. We investigated the existence of trends in estimates of daily dose, Hazard Quotient (HQ), Hazard Index (HI), and Maximum Cumulative Ratio (MCR) for six phthalates over the period of 2005 to 2014 using biomonitoring data collected under the National Health and Nutrition Examination Survey. Doses for the phthalates were estimated for each surveyed individual using reverse dosimetry. HI and MCR values were determined with the doses and the phthalates’ Tolerable Daily Intakes. HQs are a measure of chemical-specific risks, HI is a measure of cumulative risk, and MCR quantifies the degree to which a single phthalate drives the cumulative risk of an individual. There was a 2.2-fold decrease in the mean HI (0.34 to 0.15) and a 7.2-fold decrease in the percentage of participants with an HI>1 (5.1% to 0.8%), indicating an overall decrease in combined exposure to the six phthalates during this period. Decreases in the HI were due to decreased exposures to two phthalates, diethylhexyl phthalate (DEHP) and dibutyl phthalate (DBP). Children (aged 6-11 years) had higher HI values than either adolescents (aged 12-19 years) or adults (aged 20+ years) during the 10 years. These decreases were most pronounced in the groups experiencing the highest phthalates exposures. They are driven by the declines in HQs for DEHP and DBP and are offset slightly by increases in HQs for DINP. MCR values over the period were generally low and inversely correlated with HI. This indicated that a single phthalate usually drove the HI values for highly exposed individuals. However, the average value of MCR increased 1.2 fold (1.7 to 2.1) over the 10-year period indicating an increasing need to consider cumulative exposures for this group of phthalates.
