Study Measures Exposure to Free and Conjugated Forms of BPA

Canadian researchers have published a study measuring free and conjugated
forms of bisphenol A (BPA) and triclosan (TCS) in urinary samples
obtained from 2,000 pregnant women enrolled in the Maternal-Infant
Research on Environmental Chemicals (MIREC). Tye Arbuckle, et al.,
“Exposure to Free and Conjugated Forms of Bisphenol A and Triclosan
among Pregnant Women in the MIREC Cohort,” Environmental Health
Perspectives, April 2015. Billed as “the largest national-level data”
to address both the free and conjugated forms of these phenols, the
results evidently suggest that exposure varies by material age, household
income, education, and smoking factors, depending on the type of
consumer products used by individuals.

In particular, researchers detected conjugated BPA and TCS in 95 and 99
percent of samples, and free-form BPA and TCS in 43 and 80 percent of
samples, respectively. “Significant predictors of BPA included material
age < 25 vs. ≥ 35 years, current smoking, low vs. high household income,
and low vs. high education,” note the authors. “For TCS, urinary concentrations
were significantly higher in women ≥ 25 years of age, never
vs. current smokers, and women with high household income and high
education.”

The authors also argue that more biomonitoring studies are needed to
measure exposure to free BPA and TCS, as these “may be more toxicologically
active than the conjugated forms.” As they explain, “These data
will be important in assessing potential risks of these chemicals and in
developing profiles of exposure, particularly in identifying women with
elevated exposures.”

Issue 560