Analysis of human hair to assess exposure to organophosphate flame retardants: Influence of hair segments and gender differences

Abstract

Hair is a promising, non-invasive, human biomonitoring matrix that can provide insight into retrospective and integral exposure to organic pollutants. In the present study, we measured the concentrations of organophosphate flame retardants (PFRs) in hair and serum samples from university students in Guangzhou, China, and compared the PFR concentrations in the female hair segments using paired distal (5~10cm from the root) and proximal (0~5cm from the root) samples. PFRs were not detected in the serum samples. All PFRs except tricresyl phosphate (TMPP) and tri-n-propyl phosphate (TPP) were detected in more than half of all hair samples. The concentrations of total PFRs varied from 10.1 to 604ng/g, with a median of 148ng/g. Tris(chloroisopropyl) phosphate (TCIPP) and tri(2-ethylexyl) phosphate (TEHP) were the predominant PFRs in hair. The concentrations of most PFRs in the distal segments were 1.5~8.6 times higher than those in the proximal segments of the hair (t-test, p<0.05), which may be due to the longer exposure time of the distal segments to external sources. The values of log (PFR concentrations-distal/PFR concentrations-proximal) were positively and significantly correlated with log KOA of PFRs (p<0.05, r=0.68), indicating that PFRs with a higher log KOA tend to accumulate in hair at a higher rate than PFRs with a lower log KOA. Using combined segments of female hair, significantly higher PFR concentrations were observed in female hair than in male hair. In contrast, female hair exhibited significantly lower PFR concentrations than male hair when using the same hair position for both genders (0-5cm from the scalp). The controversial results regarding gender differences in PFRs in hair highlight the importance of segmental analysis when using hair as an indicator of human exposure to PFRs.

Brominated and organophosphorus flame retardants in South African indoor dust and cat hair

“…Henríquez-Hern andez et al 2017reported high detection frequencies for TCIPP, TBOEP, TCEP, EHDPP, and TPHP in cat blood. TCIPP was also found to be one of the major OPFRs found in human hair from China (He et al, 2018b;Li et al, 2016). When comparing the three main OPFR groups, Cl-OPFR, alkyl-OPFRs, and aryl-OPFRs, the Cl-OPFRs dominate the profile in dust samples and the alkyl-OPFRs in cat hair.…”

Different organophosphate flame retardant and metabolite concentrations in urine from male and female university students in Beijing and an assessment of exposure via indoor dust

“…Qiao et al (2016) found significantly higher total OPFR, triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate, and tri(2-ethylhexyl)phosphate concentrations in female hair than in male hair. Qiao et al (2016) found significantly higher total OPFR, triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate, and tri(2-ethylhexyl)phosphate concentrations in female hair than in male hair.…”

Metabolism and fate of organophosphate ester (OPE) contaminants in rainbow trout (Oncorhynchus mykiss) using in vitro lab-based studies

“…The past two years have seen an increase in studies reporting OP triesters and diesters in humans, especially in children due to concerns regarding higher exposure from increased hand-to-mouth activity. Though OPEs have not been detected in blood samples, TNBP (10 to 57 ng/g lw) and TCIPP (22 to 82 ng/g lw) were detected in breast milk samples from Sweden (Qiao et al, 2016;Sundkvist et al, 2010). Comparatively, breast milk samples from Japan (∑OPEs ranged 0.32 to 177 ng/g lw), the Philippines (∑OPEs ranged 11 to 600 ng/g lw), and Vietnam (∑OPEs ranged n.d. to 48 ng/g lw) were dominated by TCEP and TPHP.…”

“…Comparatively, breast milk samples from Japan (∑OPEs ranged 0.32 to 177 ng/g lw), the Philippines (∑OPEs ranged 11 to 600 ng/g lw), and Vietnam (∑OPEs ranged n.d. to 48 ng/g lw) were dominated by TCEP and TPHP. OPE metabolites are increasingly used as exposure biomarkers and have been detected in hair, nail, and urine samples from people living around the world (Guo et al, 2012;Hoffman et al, 2017a;Ospina et al, 2018;Qiao et al, 2016;. Cequier et al, 2015;He et al, 2018;Schreder et al, 2016).…”