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.”