Flame retardant exposure assessment: findings from a behavioral intervention study.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) have been largely replaced by organophosphate flame retardants (OPFRs) and alternative brominated flame retardants (Alt-BFRs) to meet flammability requirements. Humans are ubiquitously exposed to some variety of flame retardants through contact with consumer products directly or through household dust. OBJECTIVES: To evaluate the effectiveness of house cleaning and hand washing practices to reduce exposure to flame retardants, we measured concentrations in dermal hand wipes and urinary metabolites before and after assignment to two consecutive interventions. METHODS: We selected 32 mother and child dyads from an existing cohort. This analysis focuses on mothers. Participants provided baseline measurements (urine, hand wipes, and questionnaires) and were then assigned for 1 week to either a house cleaning (including instruction on proper technique and cleaning supplies) or hand washing (including instruction on proper technique and soaps) intervention arm. For the second week, participants were assigned to the second intervention in addition to their initial assignment, thus all subjects both washed their hands and cleaned according to the intervention guidelines during week 2. We collected measurements at the end of weeks 1 and 2. RESULTS: We found reductions in urinary analytes after week 1 of house cleaning (BCIPHIPP and ip-DPHP), week 1 of hand washing (BCIPP, BCIPHIPP, and tbutyl-DPHP), and week 2 of combined interventions (BCIPHIPP and tbutyl-DPHP), compare to baseline. We found no significant decline in hand wipes in the entire sample but did find reductions after week 1 of house cleaning (BDE 209), week 1 of hand washing (TCEP), and week 2 of combined interventions (TDCIPP and BDE 209) in women with exposure above the median at baseline (verified through simulations). CONCLUSIONS: Exposure to individual flame retardants was reduced by about half, in some cases, by 1 week of increased hand washing, house cleaning to reduce dust, or combined activities.

Differential exposure to organophosphate flame retardants in mother-child pairs.

BACKGROUND: Humans are ubiquitously exposed to flame retardants, including organophosphate esters (OPEs), through direct contact with consumer products or exposure through household dust. Children are at increased risk because of their proximity to dust, hand-to-mouth activity, and the importance of childhood as a critical period in neurodevelopment. OBJECTIVES: To quantify differences in exposure levels between mothers and children (three to six years of age), we analyzed urinary metabolites of OPEs. We additionally assessed the ability of silicone wristbands (measuring ambient exposure) to predict urinary metabolite concentrations. METHODS: We selected 32 mother and child dyads from an existing cohort. Participants provided baseline urine samples and wore wristbands for one week. After the first week, they returned their wristbands and provided a second urine sample. During the second week, participants wore a second wristband that they returned at the end of week two with a third and final urine sample. RESULTS: We found significantly higher levels of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) (p < 0.001) and lower levels of bis(1-chloro-2-isopropyl) 1-hydroxy-2-propyl phosphate (BCIPHIPP) (p < 0.001) in children's urine samples compared to mothers' samples at baseline. We found that triphenylphosphate (TPHP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), and tris(1-chloro-2-propyl) phosphate (TCIPP) measured in wristbands predicted their respective metabolite levels in urine. CONCLUSION: Children had higher levels than mothers for two of six flame retardant metabolites measured in urine. Generally, wristband measurements positively predicted internal dose. As little is known about the health effects of OPEs on child development, future research is needed to determine the impact of differential exposure.