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.

Use of fluorinated polybrominated diphenyl ethers and simplified cleanup for the analysis of polybrominated diphenyl ethers in house dust.

A simple, cost-effective method is described for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust using pressurized fluid extraction, cleanup with modified silica solid phase extraction tubes, and fluorinated internal standards. There are 14 PBDE congeners included in the method, some typically contained in the commercial mixtures used as flame retardants, and some which are not routinely reported in the peer-reviewed literature. A gas chromatographic-mass spectrometry instrumental method provides baseline separation in <20 min, detection limits <20 ng/g, and quantitation limits <60 ng/g for most congeners. Method blanks contained an average concentration <9 ng/g for all congeners except BDE209 which had an average around 40 ng/g. Spiked samples showed good accuracy with relative percent difference (RPD) <7%, and good precision with relative standard deviation <22% for all congeners except BDE209. The method was applied to the analysis of a standard dust (NIST Standard Reference Material 2585) and showed good accuracy with RPD <25% except for BDE154. Overall, this method exhibited good performance characteristics in all categories including simplicity, cost, sensitivity, selectivity, accuracy, and precision.

Flame retardant exposures in California early childhood education environments.

Infants and young children spend as much as 50h per week in child care and preschool. Although approximately 13 million children, or 65% of all U.S. children, spend some time each day in early childhood education (ECE) facilities, little information is available about environmental exposures in these environments. We measured flame retardants in air and dust collected from 40 California ECE facilities between May 2010 and May 2011. Low levels of six polybrominated diphenyl ether (PBDE) congeners and four non-PBDE flame retardants were present in air, including two constituents of Firemaster 550 and two tris phosphate compounds [tris (2-chloroethyl) phosphate (TCEP) and tris (1,3-dichloroisopropyl) phosphate (TDCIPP)]. Tris phosphate, Firemaster 550 and PBDE compounds were detected in 100% of the dust samples. BDE47, BDE99, and BDE209 comprised the majority of the PBDE mass measured in dust. The median concentrations of TCEP (319 ng g(-1)) and TDCIPP (2265 ng g(-1)) were similar to or higher than any PBDE congener. Levels of TCEP and TDCIPP in dust were significantly higher in facilities with napping equipment made out of foam (Mann-Whitney p-values<0.05). Child BDE99 dose estimates exceeded the RfD in one facility for children<3 years old. In 51% of facilities, TDCIPP dose estimates for children<6 years old exceeded age-specific "No Significant Risk Levels (NSRLs)" based on California Proposition 65 guidelines for carcinogens. Given the overriding interest in providing safe and healthy environments for young children, additional research is needed to identify strategies to reduce indoor sources of flame retardant chemicals.

Quantitative analysis of organophosphate and pyrethroid insecticides, pyrethroid transformation products, polybrominated diphenyl ethers and bisphenol A in residential surface wipe samples.

Surface wipe sampling is a frequently used technique for measuring persistent pollutants in residential environments. One characteristic of this form of sampling is the need to extract the entire wipe sample to achieve adequate sensitivity and to ensure representativeness. Most surface wipe methods require collection of multiple samples for related chemicals or chemical classes having similar physiochemical properties. In an effort to analyze a broad suite of pollutants collected from a single surface wipe sample, we developed a new method for the analysis of selected organophosphate and pyrethroid insecticides, pyrethroid transformation products (TPs), bisphenol A (BPA) and polybrominated diphenyl ethers (PBDEs). This is the first time this suite of compounds has been analyzed from a single indoor wipe sample because of the issues uniquely related to these sample types, namely high levels of interfering compounds such as phthalate esters and other residues found in the indoor environment. This new method uses extraction via sonication followed by solvent exchange into hexane, clean-up and liquid/liquid extraction. The extract portion containing insecticides and PBDEs is further purified using solid phase extraction prior to concentration and analysis. The portion containing BPA and TPs is solvent exchanged into ethyl acetate before concentration and derivatization with 99:1 trimethylsilyl 2,2,2-trifluoro-N-(trimethylsilyl)acetimidate:chlorotrimethylsilane. Wipe extract sub-classes were then analyzed by GC/MS in electron impact mode for insecticides, BPA and TPs while negative chemical ionization mode was employed for PBDEs. Method detection limits were <16.4 pg/cm(2) for all compounds with most being <5 pg/cm². Over 400 samples, including QA/QC samples, were analyzed with mean surrogate recoveries ranging from 76 to 95%. The most frequently detected chemicals from our suite were chlorpyrifos, permethrin, bisphenol A, BDE-47, BDE-99 and BDE-100. Permethrin (107 pg/cm² on floors and 18 pg/cm² on windows) and bisphenol A (110 pg/cm² on floors and 6.8 pg/cm² on windows) had the highest concentrations measured in the wipe samples. Results from the method evaluation and routine sample analysis are presented.