Distribution and exposure risk assessment of chlorinated paraffins and novel brominated flame retardants in toys

Determination of chlorinated paraffins and olefins in plastic consumer products of the Swiss market

Chlorinated paraffins (CPs) are plastic additives, which are targeted by international regulatory entities due to their persistence, bioaccumulation, potential for long-range environmental transport and adverse effects. In this work, CPs were analyzed in plastic consumer products of the Swiss market collected in 2021. Up to 144 plastic samples were pre-screened with a GC-ECD method. Plastic samples containing CPs (32, 22%) were further analyzed at homologue level by an LC-APCI-Orbitrap-HRMS method. Respective mass spectrometric data were extracted and evaluated with the CP-Hunter program at the rate of seconds per sample. Qualitative analysis of the LC-HRMS method revealed distinctive CnClx-homologue distributions of both chlorinated paraffins and olefins (COs), highlighting the diversity of CP-mixtures present in the Swiss market. The presence of C21- to C31-homologues in plastic consumer products is reported herein for the first time. Based on the specific fingerprints and the parameters deduced, these samples were grouped with a principal component analysis (PCA). Three industrial strategies were identified in the manufacturing of CP-containing plastics to either comply with or circumvent regulations. These strategies included the avoidance of the SCCP-fraction (type-A), the indiscriminate use of complex technical CP-mixtures (type-B) and the combination of technical CP-mixtures of different carbon-chain lengths and chlorination degrees (type-C). Results showed that the most used strategy was type-B and a partial substitution of SCCPs by MCCPs and LCCPs. Quantitative analysis exhibited that the SCCP content of 20 (14%) out of 144 plastic samples exceeded the Swiss legal limit of 1.5 mg SCCPs per g of plastic. The CnClx-homologue distribution of these plastic samples were type-B and type-C. Therefore, regular monitoring should be conducted to ensure that the composition of plastic products adheres to current regulations.

Investigating polychlorinated alkanes in technical chlorinated paraffin mixtures and polymer products available in Vietnam

Chlorinated paraffins (CPs) are chemical additives mostly composed of polychlorinated alkanes (PCAs) which may impact on the environment and human health; however, little is known about their presence in Southeast Asia. To fill this knowledge gap, we assessed 74 PCA homolog groups commonly referred to as short-chain (SCCPs: PCAs-C10-13), medium-chain (MCCPs: PCAs-C14-17), and long-chain CPs (LCCPs: PCAs-C18-20) in technical CP mixtures (n = 4) and polymer samples (n = 49), including recycled plastics, collected in Vietnam in 2023. The contents of measured PCA homolog groups in technical CP mixtures were 86,000-930,000 mg/kg for PCAs-C10-13; 85,000-990,000 mg/kg for PCAs-C14-17; and 23,000-180,000 mg/kg for PCAs-C18-20. Total PCAs-C10-20 levels in polymer samples varied from 0.26 to 28,000 mg/kg and decreased in the order: soft plastic bag, electrical cable sheath, football pitch rubber, polyurethane hose, heat shrinkable tubing, spiral cable cover, plastic powder, and plastic drawstring. In polymer samples, PCAs-C14-17 were found at greater levels (mean/median: 3000/65 mg/kg) than PCAs-C18-20 (1300/9.5 mg/kg) and PCAs-C10-13 (740/16 mg/kg). The contents of total measured PCAs-C10-20 in polyvinyl chloride samples varied according to their life cycle stages, with higher levels found in recycled plastics than in feedstock and commercial product samples. The occurrence of PCAs-C10-13 in polymer samples above internationally proposed limits for PCAs-C10-13 in consumer goods and waste pose a conundrum for the implementation of a safe circular economy and may impact human health in Vietnam. Therefore, this study highlights key challenges for the through implementation of the Basel, Rotterdam, and Stockholm Conventions and the importance of further comprehensive investigations in Vietnam and other developing countries.

Investigating the research landscape of chlorinated paraffins over the past ten decades

Chlorinated paraffins (CPs) are classified as emerging persistent organic pollutants (POPs). Due to their associated environmental and health impacts, these groups of chemicals have been a subject of interest among researchers in the past decades. Here we used a scientometric approach to understand the research landscape of CPs using literature published in the Web of Science and Scopus database. RStudio and VOSviewer programs were employed as scientometric tools to analyze the publication trends in global CP-related research from 1916 to 2024. A total of 1,452 articles were published over this period, with a publication/author and co-author/publication ratio of 0.43 and 5.49, respectively. China ranked first in publication output (n = 556, 43.3%), and the highest total citations (n = 12,007), followed by Sweden (n = 90), Canada (n = 77), and Germany (n = 75). Publications from developing countries were limited, with most contributions from Africa originating from Egypt (n = 7), South Africa (n = 5), and Nigeria (n = 3), primarily through international collaborations. The average annual growth rate of 4.3% suggests a significant future article output. This scientometric analysis allowed us to infer global trends in CPs, identify tendencies and gaps, and contribute to future research. Despite having similar toxicity to short-chain chlorinated paraffin (SCCP), long-chain chlorinated paraffin (LCCP) has received less attention. Therefore, future research should prioritize studying LCCP bioaccumulation and toxicity in diverse food webs, focusing on aquatic species vulnerable to CPs and effective toxicological models. Additionally, collaborative research with developing countries should be encouraged to enhance meeting the Stockholm Convention's demand.

Global quantification of emerging and legacy per- and polyfluoroalkyl substances in indoor dust: Levels, profiles and human exposure

This study investigated the occurrence and distribution of per- and polyfluoroalkyl substances (PFASs) in house dust samples from six regions across four continents. PFASs were detected in all indoor dust samples, with total median concentrations ranging from 17.3 to 197 ng/g. Among the thirty-one PFAS analytes, eight compounds, including emerging PFASs, exhibited high detection frequencies in house dust from all six locations. The levels of PFASs varied by region, with higher concentrations found in Adelaide (Australia), Tianjin (China), and Carbondale (United States, U.S.). Moreover, PFAS composition profiles also differed among regions. Dust from Australia and the U.S. contained high levels of 6:2 fluorotelomer phosphate ester (6:2 diPAP), while perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were predominant in other regions. Furthermore, our results indicate that socioeconomic factors impact PFAS levels. The assessment of human exposure through dust ingestion and dermal contact indicates that toddlers may experience higher exposure levels than adults. However, the hazard quotients of PFASs for both toddlers and adults were below one, indicating significant health risks are unlikely. Our study highlights the widespread occurrence of PFASs in global indoor dust and the need for continued monitoring and regulation of these chemicals.

Exposure to Short- and Medium-Chain Chlorinated Paraffins and the Risk of Gestational Diabetes Mellitus: A Nested Case-Control Study in Eastern China

Toxicological studies have indicated that exposure to chlorinated paraffins (CPs) may disrupt intracellular glucose and energy metabolism. However, limited information exists regarding the impact of human CP exposure on glucose homeostasis and its potential association with an increased risk of developing gestational diabetes mellitus (GDM). Here, we conducted a prospective study with a nested case-control design to evaluate the link between short- and medium-chain CP (SCCPs and MCCPs) exposures during pregnancy and the risk of GDM. Serum samples from 102 GDM-diagnosed pregnant women and 204 healthy controls were collected in Hangzhou, Eastern China. The median (interquartile range, IQR) concentration of SCCPs was 161 (127, 236) ng/mL in the GDM group compared to 127 (96.9, 176) ng/mL in the non-GDM group (p < 0.01). For MCCPs, the GDM group had a median concentration of 144 (117, 174) ng/mL, while the control group was 114 (78.1, 162) ng/mL (p < 0.01). Compared to the lowest quartile as the reference, the adjusted odds ratios (ORs) of GDM were 7.07 (95% CI: 2.87, 17.40) and 3.34 (95% CI: 1.48, 7.53) in the highest quartile of ∑SCCP and ∑MCCP levels, respectively, with MCCPs demonstrating an inverted U-shaped association with GDM. Weighted quantile sum regression evaluated the joint effects of all CPs on GDM and glucose homeostasis. Among all CP congeners, C13H23Cl5 and C10H16Cl6 were the crucial variables driving the positive association with the GDM risk. Our results demonstrated a significant positive association between CP concentration in maternal serum and GDM risk, and exposure to SCCPs and MCCPs may disturb maternal glucose homeostasis. These findings contribute to a better understanding of the health risks of CP exposure and the role of environmental contaminants in the pathogenesis of GDM.

Short- and medium-chain chlorinated paraffins in T-shirts and socks

The short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) are complex mixtures of persistent compounds used mainly as plastic additives. They can have a negative impact on human health as they are suspected of disrupting the endocrine system and being carcinogenic, which is why monitoring their presence in the human environment is desirable. Clothing was selected for this study because they are produced in large quantities worldwide and the final products are worn for long periods throughout the day, in direct contact with human skin. The concentrations of CPs in this type of sample have not been sufficiently reported. We determined SCCPs and MCCPs in 28 samples of T-shirts and socks by gas chromatography coupled with high-resolution mass spectrometry in negative chemical ionisation mode (GC-NCI-HRMS). CPs were found above the limits of quantification in all samples, with concentrations ranging from 33.9 to 5940 ng/g (mean 1260 ng/g, median 417 ng/g). The samples with a substantial proportion of synthetic fibres contained higher CP concentrations (22 times higher mean for SCCPs and 7 times higher mean for MCCPs) than garments composed exclusively of cotton. Finally, the effect of washing in the washing machine was investigated. The individual samples behaved differently: (i) excessively emitting CPs; (ii) being contaminated; (iii) retaining the original CP levels. The CP profiles also changed for some samples (with a substantial proportion of synthetic fibres and samples composed exclusively of cotton).