Flame retardants and their metabolites in the homes and urine of pregnant women residing in California (the CHAMACOS cohort)

Abstract

Organophosphate flame retardants (PFRs), used in consumer products since the 1970s, persist in the environment. Restrictions on penta-polybrominated diphenyl ether (PBDE) flame retardants resulted in increased use of Firemaster^® 550 (FM^® 550), and the organophosphate triesters: tris(1,3- dichloro-2-propyl) phosphate (TDCIPP); tris(chloropropyl) phosphate (TCIPP); tris(2-chloroethyl) phosphate (TCEP); and triphenyl phosphate (TPHP). The objectives of this study were to (1) identify determinants of flame retardants (4 PFRs, PentaBDEs and FM^® 550) in house dust, (2) measure urinary PFR metabolites in pregnant women, and (3) estimate health risks from PFR exposure. We measured flame retardants in house dust (n = 125) and metabolites in urine (n = 310) collected in 2000-2001 from Mexican American women participating in the CHAMACOS birth cohort study in California. We detected FM^® 550 and PFRs, including two (TCEP and TDCIPP) known to the state of California to cause cancer, in most dust samples. The maximum TCEP and TDCIPP dust levels were among the highest ever reported although the median levels were generally lower compared to other U.S. cohorts. Metabolites of TDCIPP (BDCIPP: bis(1,3-dichloro-2-propyl) phosphate) and TPHP (DPHP: diphenyl phosphate) were detected in 78% and 79% of prenatal urine samples, respectively. We found a weak but positive correlation between TPHP in dust and DPHP in 124 paired prenatal urine samples (Spearman rho = 0.17; p = 0.06). These results provide information on PFR exposure and risk in pregnant women from the early 2000's and are also valuable to assess trends in exposure and risk given changing fire safety regulations and concomitant changes in chemical flame retardant use.

Keywords: Dust; Exposure; Flame retardants; Pregnant women; Urinary metabolites.

Figure 1

Median PFR and Firemaster® 550 levels in dust (CHAMACOS 2000-01) compared to other studies. * Star indicates analyte not measured. ^a Meeker and Stapleton, 2010; ^b Bradman et al., 2014; ^c Dodson et al., 2012 (Two sampling periods); ^d Schreder and La Guardia, 2014; ^e Stapleton et al., 2014; ^f Hoffman et al., 2015; ^g Brown et al., 2014. Note: Year of sample collection is provided in parentheses.

Figure 2

Carpet wear and flame retardant levels in house dust. * ANOVA p<0.05 (TCEP); p=0.08 (TCIPP and Σ Penta-BDEs)