Human exposure pathways to organophosphate triesters — A biomonitoring study of mother–child pairs

Abstract

The worldwide ban of several formulations of brominated flame retardants has caused an increase in the production of organophosphorus flame retardants (PFRs) to meet the existing fire regulations for a wide range of household products. This biomonitoring study surveys the occurrence of the metabolites from PFRs and related plasticizers (dialkyl and diaryl phosphates; DAPs) in urine from a Norwegian mother-child cohort (48 mothers and 54 children). Concentrations of DAPs were higher in the children than in their mothers (Wilcoxon signed-rank test p=0.001). Median urinary concentrations of diphenyl phosphate (DPHP) were 1.1 and 0.51ng/mL in children and mothers, respectively, followed by bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) with medians of 0.23 and 0.12ng/mL, respectively. Detection frequencies for bis(2-butoxyethyl) phosphate (BBOEP) in urine from children and mothers were 32 and 1%, respectively (median<0.18ng/mL), and for di-n-butyl phosphate (DNBP) 15 and 8%, respectively (median<0.12ng/mL). The concentrations of DPHP and BDCIPP in urine from children were significantly correlated with those found for their parent compounds in air and dust from the households (Spearman's rank correlations 0.30<Rs<0.36; p<0.05). For mothers, only the urinary concentration of BDCIPP was correlated to its precursor in dust from the households (Rs=0.40; p<0.01), which might indicate higher impact of the household environment on children than mothers. A diurnal variability study of the mothers' urinary concentrations of DPHP and BDCIPP showed lower concentrations at time periods when women were likely to be outside the household. In contrast, no relevant associations between organophosphate metabolites in urine and food consumption data obtained through a 24hour recall were seen. This suggests that the residential environment is a more important exposure pathway to PFRs than the diet.

Review of OPFRs in animals and humans: Absorption, bioaccumulation, metabolism, and internal exposure research

“…54% and 41%, respectively) in Oslo, Norway. Cequier et al (2015) subsequently concluded the household inhalation was a more important absorption pathway of OPFRs than through the diet for motherchild pairs in Norway. But more biomonitoring studies are needed to further discuss the contribution of various absorption pathways of OPFRs for human.…”

“…Recently, quantified DAPs and MAPs in urine have been identified as biomarkers to assess human exposure. In total, DAPs of BDCIPP, BCIPP, BCEP, BBOEP, DBP, DPHP, DEHP and some MAPs of MEHP, MBP, MCIPP, MBOEP and MPHP have been quantified in human urine, with median concentrations in the ng ml À1 range (Butt et al, 2014;Cequier et al, 2014bCequier et al, , 2015Chu et al, 2011;Cooper et al, 2011;Dodson et al, 2014;Fromme et al, 2014;Hoffman et al, 2015;Meeker et al, 2013a,b;Moller et al, 2004;Petropoulou et al, 2016;Reemtsma et al, 2011;Schindler et al, 2009a,b;Van den Eede et al, 2015b;Van den Eede et al, 2013b) (SI Table S2). However, no information is available for DAPs and MAPs or other OPFR metabolites from internal exposure studies of wild animals.…”

Occurrence, distribution and seasonal variation of organophosphate flame retardants and plasticizers in urban surface water in Beijing, China

“…The reports associated with human exposure have demonstrated the reduction of sperm counts and hormone levels due to the exposure to TPhP and TDCP (Meeker and Stapleton, 2010). TCEP and TDCP are considered as carcinogens and potential neurotoxicants (Cequier et al, 2015;Salamova et al, 2014a), and may cause acute or chronic adverse effects to aquatic organisms (Cristale et al, 2013a;Kim et al, 2011). TCPP is also a suspected carcinogen (Reemtsma et al, 2008), and TnBP has neurotoxic properties after chronic exposure (Reemtsma et al, 2008).…”

Tris(pentafluoroethyl)trifluorophosphate-basd ionic liquids as advantageous solid-phase micro-extraction coatings for the extraction of organophosphate esters in environmental waters

“…In fact, OPEs are already ubiquitous in various environments, as they have been detected in sewage treatment plants (STPs) [3], indoor environments [4,5], atmospheric particles [6,7], aquatic environment [2,[7][8][9], biota [10,11] and also human body fluid [10,12]. Moreover, some halogenated OPEs, such as tris(2-chloroethyl)phosphate (TCEP), tris(chloroisopropyl)phosphate (TCPP) and tris(1,3-dichloro-2-propyl)phosphate (TDCP), are quite recalcitrant to naturally degradation or biodegradation [1,3], suggesting that they are likely to enter the aquatic environment and persistent in environment.…”

“…Moreover, some halogenated OPEs, such as tris(2-chloroethyl)phosphate (TCEP), tris(chloroisopropyl)phosphate (TCPP) and tris(1,3-dichloro-2-propyl)phosphate (TDCP), are quite recalcitrant to naturally degradation or biodegradation [1,3], suggesting that they are likely to enter the aquatic environment and persistent in environment. In addition, extensive studies have showed that exposure to several OPEs pose a potential health risk for animals and humans [12][13][14].…”