Temporal Trends in Exposures to Six Phthalates from Biomonitoring Data: Implications for Cumulative Risk

Phthalates
are used in a wide range of consumer goods, resulting
in exposures to specific phthalates that vary over time in accordance
with changes in product use and how phthalates are utilized. We investigated
trends in estimates of daily intake dose and several cumulative risk
metrics, including the Hazard Quotient (HQ), Hazard Index (HI), and
Maximum Cumulative Ratio (MCR) for six phthalates from 2005 to 2014
using metabolite biomonitoring data collected from spot urine samples
under the National Health and Nutrition Examination Survey (NHANES).
Over this period, 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 (5.7% to 0.8%), indicating an overall decrease in
combined
exposure to these phthalates. Children (aged 6–11 years) had
higher mean HI values than either adolescents (aged 12–19 years)
or adults (aged 20+ years) during this period. MCR values were generally
low and inversely correlated with HI. This indicated that a single
phthalate usually drove the hazards for highly exposed individuals.
However, the average value of MCR increased 1.2-fold (1.7–2.1)
over this period indicating an increasing need to consider exposures
to multiple phthalates in this group.