Mass Fractions, Congener Group Patterns, and Placental Transfer of Short- and Medium-Chain Chlorinated Paraffins in Paired Maternal and Cord Serum

Abstract

Multiple studies have demonstrated the occurrences of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in environmental matrixes, but human internal exposure to them has been studied rarely. Mass fractions and congener group patterns of SCCPs and MCCPs in paired maternal and cord serum were studied for the first time to investigate the placental transport mechanism and prenatal exposure risks of CPs. Samples were collected in Beijing, China, and analyzed using two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. SCCP and MCCP mass fractions in maternal serum were 21.7-373 and 3.76-31.8 ng/g ww, respectively. They were 8.51-107 and 1.33-12.9 ng/g ww, respectively, in cord serum. Significant positive correlation between SCCP and MCCP levels in maternal serum was found ( p < 0.01), suggesting SCCPs and MCCPs may undergo similar accumulation, transfer, and transformation pathways. The predominant congener groups for SCCP and MCCP in maternal serum were CCl and CCl. The homologue profiles of CPs in cord serum were similar but with varied contribution percentage compared with those in maternal serum. By calculating and comparing cord-maternal serum ratios for each individual congener group, passive diffusion was recognized to be the possible placental transport form. The relationships between CP and thyroid hormone concentrations (THs) indicated that exposure to CPs might affect circulating TSHs. C-CPs were also detected, improving our understanding of CPs in human serum.

Status of short-chain chlorinated paraffins in matrices and research gap priorities in Africa: a review

“…Human serum Liu et al (2020b) reported ∑SCCP concentration in maternal and placenta human serum samples of about 117.1 ng mL −1 and 70.0 ng mL −1 , respectively, which were in the same range with those reported by Aamir et al (2019) and Qiao et al (2018). Ding et al (2020) also determined SCCP concentration in serum samples of about 107 ng g −1 ww, which were comparable with those previously reported in blood samples (Qiao et al 2018).…”

“…Human serum Liu et al (2020b) reported ∑SCCP concentration in maternal and placenta human serum samples of about 117.1 ng mL −1 and 70.0 ng mL −1 , respectively, which were in the same range with those reported by Aamir et al (2019) and Qiao et al (2018). Ding et al (2020) also determined SCCP concentration in serum samples of about 107 ng g −1 ww, which were comparable with those previously reported in blood samples (Qiao et al 2018). SCCP concentrations in serum samples Arctic between 2011 and 2012 7.1±0.7 ng/g dw ranging from 1.00 to 5.45 ng mL −1 were determined by Zhou et al (2019), which were lower than those obtained in plasma (Li et al 2017b) and human blood (Xu et al 2019c).…”

“…In Australia, a study done by van Mourik et al (2020a) showed SCCP concentration in human male serum samples which ranged from <MDL to 0.68 with ∑SCCPs of 0.54 ng g −1 ww. The concentrations obtained were lower than those obtained in human, maternal and cord serum samples from China (Zhou et al 2019;Qiao et al 2018). In addition to the SCCP studies reviewed above, Table 4 summarizes SCCP studies in different matrices from different continents.…”

Chlorinated Paraffin Levels in Relation to Other Persistent Organic Pollutants Found in Pooled Human Milk Samples from Primiparous Mothers in 53 Countries

“…According to newer transfer studies, CPs in human milk are likely to have been in maternal blood as well ( Chen et al. 2020 ), which was shown through paired maternal and umbilical cord serum samples to signify a transfer to the offspring through the placenta ( Qiao et al. 2018 ).…”

Complex Mixtures of Chlorinated Paraffins Found in Hand Wipes of a Norwegian Cohort

“… 22 All CPs are persistent, 23 and they are bioaccumulative in humans. 24 , 25 Mammalian toxicity research has mostly focused on SCCPs 26 and has identified SCCPs as possible carcinogens to humans. 27 Although the toxicity of MCCPs and LCCPs has been studied less, MCCPs are considered to meet the REACH toxicity criteria, 28 and MCCP exposure has been shown to cause hemorrhaging effects in rats.…”