Polybrominated diphenyl ether serum concentrations in a Californian population of children, their parents, and older adults: an exposure assessment study.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in many household items. Given concerns over their potential adverse health effects, we identified predictors and evaluated temporal changes of PBDE serum concentrations. METHODS: PBDE serum concentrations were measured in young children (2-8 years old; N = 67), parents of young children (<55 years old; N = 90), and older adults (≥55 years old; N = 59) in California, with concurrent floor wipe samples collected in participants' homes in 2008-2009. We also measured serum concentrations one year later in a subset of children (N = 19) and parents (N = 42). RESULTS: PBDE serum concentrations in children were significantly higher than in adults. Floor wipe concentration is a significant predictor of serum BDE-47, 99, 100 and 154. Positive associations were observed between the intake frequency of canned meat and serum concentrations of BDE-47, 99 and 154, between canned meat entrees and BDE-154 and 209, as well as between tuna and white fish and BDE-153. The model with the floor wipe concentration and food intake frequencies explained up to 40% of the mean square prediction error of some congeners. Lower home values and renting (vs. owning) a home were associated with higher serum concentrations of BDE-47, 99 and 100. Serum concentrations measured one year apart were strongly correlated as expected (r = 0.70-0.97) with a slight decreasing trend. CONCLUSIONS: Floor wipe concentration, food intake frequency, and housing characteristics can explain 12-40% of the prediction error of PBDE serum concentrations. Decreasing temporal trends should be considered when characterizing long-term exposure.

Urinary pyrethroid and chlorpyrifos metabolite concentrations in Northern California families and their relationship to indoor residential insecticide levels, part of the Study of Use of Products and Exposure Related Behavior (SUPERB).

Since the 2001 U.S. federally mandated phase-out of residential uses of organophosphates (OPs), use of and potential for human exposure to pyrethroids in the indoor residential environment has increased. We report concentrations of common pyrethroids, pyrethroid metabolites, and chlorpyrifos in floor wipes, and urinary concentrations of pyrethroid metabolites and 3,5,6-trichloro-2-pyridinol (TCPy) in samples collected in 2007-2009 from 90 northern California families as part of the Study of Use of Products and Exposure Related Behavior (SUPERB). Correlation and regression analyses examined associations between floor wipe and urine sample concentrations. The most frequently detected urinary metabolites were TCPy (64.7%, median concentration of 1.47 ng/mL) and 3-phenoxybenzoic acid (3PBA) (62.4%, 0.79 ng/mL). Compared to the National Health and Nutrition Examination Survey (NHANES) 2001-2002 general U.S. population, this population had substantially higher pyrethroid metabolite and lower TCPy urinary concentrations. This may be related to the increased residential use of pyrethroids after the phase-out of OPs. Chlorpyrifos (98.7%), cis- and trans-permethrin (97.5%), bifenthrin (59.3%), and 3PBA (98.7%) were frequently detected in the floor wipes. Floor wipe concentrations for pyrethroid insecticides were found to be significant predictors of child creatinine-adjusted urinary metabolite concentrations (log-log regression coefficients ranging from 0.26 to 0.29; p < 0.05) suggesting that indoor residential exposure to pyrethroid insecticides is an important exposure route for children.