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

From environment to free-range chickens: Broad exposure to short- and medium-chain chlorinated paraffins in rural Tibetan Plateau, China

Chlorinated paraffins (CPs) are widely employed in various consumer products. Rapid socioeconomic development drives the elevation of CPs contamination by increasing the usage of modern lifestyle products, but limited information exists about their occurrence in remote rural areas. In this study, the occurrence, and profiles of short- and medium-chain CPs (SCCPs and MCCPs) in soils, plants, chicken feeds, eggs, and free-range chicken tissues in the rural Tibetan Plateau were investigated. The median concentrations of SCCPs and MCCPs were 108 and 141 ng/g dry weight (dw) in soils, 1.76 × 103 and 1.16 × 103 ng/g dw in plants, 43.6 and 24.3 ng/g dw in chicken feeds, 299 and 251 ng/g lipid weight in free-range chicken eggs, and 182 -3.45 × 103 and 396 -7.75 × 103 ng/g lipid weight in chicken tissues, respectively. Correlation analysis demonstrated that soil was the primary source of CPs, and free-range chicken eggs were effective bioindicators for SCCPs and MCCPs contamination. Tissue distribution showed that SCCPs and MCCPs were highly accumulated in chicken tissues that local resident preferred to consume (such as muscle and stomach). Our findings lay the foundations for further evaluation of the potential risks of CPs on the ecosystem and human health in remote rural areas.

Tibetan lake sediment records reveal historical emission and long-range atmospheric transport of chlorinated paraffins

The Tibetan Plateau, a recognized global sink for Persistent Organic Pollutants (POPs), lies adjacent to two major emitting regions, inland China and India. This unique geographical setting makes it a pivotal site for examining the presence and compositional evolution of POPs following their long-range atmospheric transport (LRAT). This study focuses on the current predominant POPs, chlorinated paraffins (CPs). We comprehensively screened 675 homologues of the very short- (vSCCPs), short- (SCCPs), medium- (MCCPs), and long-chain CPs (LCCPs) in six dated sediment cores across the extensive Tibetan area. The findings unveiled pronounced temporal disparities in CP concentrations and compositions between Tibet's southern and eastern sectors, reflecting divergent usage and emission chronicles of inland China and India. Notably, a market shift in China from regulated SCCPs to the in-use MCCPs and LCCPs was observed in the 21st century, contrasting with India's unregulated production of SCCPs. The Organization for Economic Cooperation and Development (OECD) Screening Tool, developed to assess the overall persistence (POV) and long-range transport potential (LRTP) of organic chemicals, elucidated the erosion of CP source signatures induced by fractionation, a process that intensifies with transport distance from the source regions. This study enhances our understanding of the emission inventories and LRAT behavior of these transitional regulatory contaminants, highlighting the Tibetan Plateau's crucial role as an environmental sentinel in global pollution dynamics.

Application of pattern deconvolution strategies for the estimation of bromochloro alkane concentrations in indoor dust samples

Bromochloro alkanes (BCAs) are a class of flame retardants similar in structure to polychlorinated alkanes (PCAs), which are the major component of short-chain chlorinated paraffins (SCCPs) listed as Persistent Organic Pollutants under the Stockholm Convention. BCAs have recently been detected for the first time in environmental samples. Due to the complete lack of commercially available analytical standards, no method for quantifying BCAs has been reported to date. In this study, 16 custom-synthesised standards with mixed bromine and chlorine halogenation and carbon chain lengths ranging from C10 to C17 were characterized by liquid chromatography and Orbitrap high-resolution mass spectrometry and used to assess the applicability of pattern deconvolution quantification strategies for BCAs in indoor dust. Br1-9 and Cl1-8 BCAs were detected as [M + Cl]- adduct ions among the C10 to C17 standards, as well as numerous PCA homologues. After applying correction factors to account for the presence of PCAs in the standards, triplicate fortification experiments using varied halogenation composition and concentration determined an average measurement accuracy of 81% over the carbon chain lengths studied and coefficient of variance ≤20% between replicates. Overall, approximately 89% of the ΣBCA concentrations quantified in the fortification trials met the European Union Reference Laboratory's accuracy acceptability criteria recommended for PCAs, between 50 and 150%. Application of the BCA pattern deconvolution quantification procedure to seven representative indoor dust samples from the United States of America revealed a low correlation between the homologue distribution in the samples and the prototype standards (R2 ≤ 0.40), which precluded reliable quantification. This study indicates that pattern deconvolution is an appropriate strategy for quantifying BCAs in environmental samples, but that a large set of appropriate mixture standards will be required before more reliable estimates of BCA concentrations can be achieved in indoor dust.

Are We Justified in Modeling Human Exposure to Chlorinated Paraffin Mixtures Using the Average Properties of Congeners and Homologues?

Concern over human exposure to chlorinated paraffin (CP) mixtures keeps increasing. The absence of a comprehensive understanding of how human exposure varies with the physicochemical properties of CP constituents has hindered the ability to determine at what level of aggregation exposure to CPs should be assessed. We answer this question by comparing exposure predicted with either a "complex" method that utilizes isomer-specific properties or "simplified" methods that rely on median properties of congener, homologue, or short-/medium-/long-chain CP groups. Our results demonstrate the wide range of physicochemical properties across CP mixtures and their dependence on molecular structures. Assuming unit emissions in the environment, these variances translate into an extensive disparity in whole-body concentrations predicted for different isomers, spanning ∼11 orders of magnitude. CPs with 13-19 carbons and 6-10 chlorines exhibit the highest human exposure potential, primarily owing to moderate to high hydrophobicity and slow environmental degradation and biotransformation. Far-field exposure is dominant for most CP constituents. Our study underscores that using average properties of congener, homologue, or S/M/LCCP groups yields results that are consistent with those derived from isomer-based modeling, thus offering an efficient and practical framework for future risk assessments and human exposure studies of CPs and other complex chemical mixtures.

In vitro assessment of potential endocrine disrupting activities of chlorinated paraffins of various chain lengths

The production of chlorinated paraffins (CPs) has risen in the past two decades due to their versatile industrial applications. Consequently, CPs are now widely detected in human food sources, the environment, and in human matrices such as serum, the placenta and breast milk. This raises concern about prenatal and postnatal exposure. While some studies suggest that certain short-chained CPs (SCCPs) may have endocrine disrupting properties, knowledge about potential endocrine disrupting potential of medium- (MCCP) and long-chained CPs (LCCPs) remains relativity sparse. Here, we used a panel of in vitro assays to investigate seven pure CPs and two technical mixtures of CPs. These varied in chain length and, chlorination degree. The in vitro panel covered androgen, estrogen, and retinoic acid receptor activities, transthyretin displacement, and steroidogenesis. One of the SCCPs inhibited androgen receptor (AR) activity. All SCCPs induced estrogen receptor (ER) activity. Some SCCPs and MCCPs increased 17β-estradiol levels in the steroidogenesis assay, though not consistently across all substances in these groups. SCCPs exhibited the most pronounced effects in multiple in vitro assays, while the tested LCCPs showed no effects. Based on our results, some CPs can have endocrine disrupting potential in vitro. These findings warrant further examinations to ensure that CPs do not cause issues in intact organisms, including humans.

Polychlorinated alkanes in paired blood serum and breast milk in a Swedish cohort study: Matrix dependent partitioning differences compared to legacy POPs

BACKGROUND

Polychlorinated alkanes (PCAs) constitute a large group of individual congeners originating from commercial chlorinated paraffin (CP) products with carbon chain lengths of PCAs-C10-13, PCAs-C14-17, and PCAs-C18-32, occasionally containing PCAs-C6-9 impurities. The extensive use of CPs has led to global environmental pollution of PCAs. This study aimed to quantify PCAs in paired serum and breast milk of lactating Swedish mothers, exploring their concentration relationship.

METHODS

Twenty-five paired samples of mothers' blood serum and breast milk were analysed and concentrations were determined for PCAs C6-32 and compared to 4,4'-DDE, the PCB congener 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), and hexachlorobenzene (HCB).

RESULTS

The median concentrations of PCAs-C6-9, PCAs-C10-13, PCAs-C14-17, PCAs-C18-32 and ΣPCAs in serum were 14, 790, 520, 16 and 1350 ng/g lipid weight (lw), respectively, and in breast milk 0.84, 36, 63, 6.0 and 107 ng/g lw. Levels of 4,4'-DDE, CB-153 and HCB were comparable in the two matrices, serum and breast milk at 17, 12 and 4.9 ng/g lw. The results show significant differences of PCAs-C10-13 and PCAs-C14-17 in breast milk with 22- and 6.2-times lower lw-based concentrations than those measured in serum. On wet weight the differences serum/breast milk ratios of PCAs-C6-9, PCAs-C10-13, PCAs-C14-17, PCAs-C18-32 and ΣPCAs were 1.7, 3.2, 1.0, 0.4 and 1.6, respectively, while the ratio for 4,4'-DDE, CB-153 and HCB were each close to 0.1.

CONCLUSION

Swedish lactating mothers had high serum concentrations of PCAs-C10-13 and PCAs-C14-17, with the ΣPCAs median serum concentration of 1350 ng/g lw. The breast milk concentration, although considerably lower at 107 ng/g lw, still surpassed those of 4,4'-DDE, CB-153 and HCB, suggesting an exposure risk of infants to PCAs. The variation in blood and breast milk accumulation between PCAs and studied legacy POPs, is rarely discussed but warrants further studies on partitioning properties as well as associated toxicological implications.

Exposure and human health risk assessment of chlorinated paraffins in indoor and outdoor dust from a metropolitan city, Lahore, Pakistan

Chlorinated paraffins (CPs) are widely used in commercial products due to their stability and durability and are subsequently released in the environment posing serious health risks in human population. In this study, dust samples from indoor and outdoor settings of residential, commercial and industrial zones as well as from vehicles were collected from a metropolitan city, Lahore, Pakistan. A total of 83 dust samples were analyzed for short (SCCPs) and medium (MCCPs) chained CPs through quadrupole time of flight mass spectrometer in atmospheric pressure chemical ionization (APCI QToF-MS) mode. The median concentrations of ƩCPs (C10-17) in outdoor dust were higher than indoor dust in industries (0.97 vs 0.48 μg/g), and residential areas (0.70 vs 0.13 μg/g) while lower in commercial areas (0.28 vs 0.44 μg/g) reflecting their higher prevalence in industrial and residential zones. The vehicular dust had median ƩCPs of 0.16 μg/g which was similar to residential indoor dust. Overall, ƩSCCPs were dominant among all zones with C10,12 and Cl7-8 as abundant carbon and chlorine congeners in both indoor and outdoor dusts. No significant correlations were observed between indoor and outdoor dust for ƩSCCPs and ƩMCCPs indicating their varying exposure. Health hazard index and margin of exposure revealed that toddlers were at higher risk compared to adults as a results of CPs exposure from both indoor and outdoor environments. This is the first ever assessment of CPs in Pakistan reflecting higher prevalence of SCCPs than MCCPs in dust of local environment posing some serious health consequences hence needed intensive investigation and effective management.

An international investigation of chlorinated paraffin concentrations and homologue distributions in indoor dust

In this study, very short-, short-, medium-, and long-chain chlorinated paraffins (vSCCPs, SCCPs, MCCPs and LCCPs, respectively) were measured in 40 indoor dust samples from four countries including Japan (n = 10), Australia (n = 10), Colombia (n = 10) and Thailand (n = 10). Homologues of the chemical formula CxH(2x+2-y)Cly ranging C6-36 and Cl3-30 were analysed using liquid chromatography coupled to Orbitrap high resolution mass spectrometry (LC-Orbitrap-HRMS) and integrated using novel custom-built CP-Seeker software. CPs were detected in all dust samples with MCCPs the dominant homologue group in all countries. Overall median ∑SCCP, ∑MCCP and ∑LCCP (C18-20) concentrations determined in dust samples were 30 μg/g (range; 4.0-290 μg/g), 65 μg/g (range; 6.9-540 μg/g) and 8.6 μg/g (range; <1.0-230 μg/g), respectively. Of the quantified CP classes, overall concentrations were generally highest in the samples from Thailand and Colombia, followed by Australia and Japan. vSCCPs with C≤9 were detected in dust from each country with an overall frequency of 48%, while LCCPs (C21-36) were present in 100% of samples. Estimated daily intakes (EDIs) calculated for SCCPs and MCCPs relating to ingestion of contaminated indoor dust were considered not to represent health risks based on currently available toxicological data using the margin of exposure (MOE) approach. To the authors' knowledge, this study provides the first data on CPs in indoor dust from Japan, Colombia and Thailand, and is among the first reports of vSCCPs in indoor dust, globally. These findings indicate that further toxicological data and the availability of appropriate analytical standards are needed to evaluate the potential for negative health outcomes deriving from exposure to vSCCPs and LCCPs.

Homologue Composition of Technical Chlorinated Paraffins Used in Several Countries over the Last 50 Years─SCCPs Are Still Out There

Chlorinated paraffins (CPs) are widely produced chemicals, with certain CP subgroups facing global restrictions due to their environmental dispersion, persistence, bioaccumulation, and toxicity. To evaluate the effectiveness of these international restrictions, we assessed the homologue group contribution and the mass fraction of short-chain CPs (SCCPs: C10-C13), medium-chain CPs (MCCPs: C14-C17), and long-chain CPs (LCCPs: ≥C18) in 36 technical CP mixtures used worldwide over the last 50 years. Using low-resolution mass spectrometry (LC-ESI-MS/MS), we quantified 74 CP homologue groups (C10Cl4-C20Cl10). Additionally, high-resolution mass spectrometry (LC-ESI-QTOF-MS) screening was employed to identify unresolved CP contents, covering 375 CP homologue groups (C6Cl4-C30Cl30). Overall, 1 sample was mainly composed of Collapse

Key Words

• chemical additive
• chlorinated n-alkane
• flame retardant
• persistent organic pollutant
• plasticizer
• polychlorinated alkane
• suspect screening analysis

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MESH Headings

• Paraffin
• Tandem Mass Spectrometry
• Chromatography, Liquid

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Grants Collapse

Affiliation(s)

Yago Guida Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, 21941-902 Rio de Janeiro, Brazil
Hidenori Matsukami Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
Gabriel Oliveira de Carvalho Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, 21941-902 Rio de Janeiro, Brazil
Roland Weber POPs Environmental Consulting, 73527 Schwäbisch Gmünd, Germany
Walter Vetter Institute of Food Chemistry (170b), University of Hohenheim, DE-70593 Stuttgart, Germany
Natsuko Kajiwara Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan

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Toxic effects and toxicological mechanisms of chlorinated paraffins: A review for insight into species sensitivity and toxicity difference

Chlorinated paraffins (CPs), a group of chlorinated alkane mixtures, are frequently detected in various environmental matrices and human bodies. Recently, CPs have garnered considerable attention owing to their potential to induce health hazards in wildlife and human. Several reviews have discussed short-chain CPs (SCCPs) induced ecological risk; however, a comprehensive understanding of the underlying toxic mechanisms and a comparison among SCCPs, medium-, and long-chain CPs (MCCPs and LCCPs, respectively) are yet to be established. This review summarizes the latest research progress on the toxic effects and the underlying molecular mechanisms of CPs. The main toxicity mechanisms of CPs include activation of several receptors, oxidative stress, disturbance of energy metabolism, and inhibition of gap junction-mediated communication. The sensitivity of different species to CP-mediated toxicities varies markedly, with aquatic organisms exhibiting the highest sensitivity to CP-induced toxicity. The toxicity comparison analysis indicated that MCCPs may be unsafe as potential substitutes for SCCPs.

Chlorinated paraffins and dechloranes in free-range chicken eggs and soil around waste disposal sites in Tanzania

Electronic waste is a source of both legacy and emerging flame retardants to the environment, especially in regions where sufficient waste handling systems are lacking. In the present study, we quantified the occurrence of short- and medium chain chlorinated paraffins (SCCPs and MCCPs) and dechloranes in household chicken (Gallus domesticus) eggs and soil collected near waste disposal sites on Zanzibar and the Tanzanian mainland. Sampling locations included an e-waste facility and the active dumpsite of Dar es Salaam, a historical dumpsite in Dar es Salaam, and an informal dumpsite on Zanzibar. We compared concentrations and contaminant profiles between soil and eggs, as free-range chickens ingest a considerable amount of soil during foraging, with potential for maternal transfer to the eggs. We found no correlation between soil and egg concentrations or patterns of dechloranes or CPs. CPs with shorter chain lengths and higher chlorination degree were associated with soil, while longer chain lengths and lower chlorination degree were associated with eggs. MCCPs dominated the CP profile in eggs, with median concentrations ranging from 500 to 900 ng/g lipid weight (lw) among locations. SCCP concentrations in eggs ranged from below the detection limit (LOD) to 370 ng/g lw. Dechlorane Plus was the dominating dechlorane compound in all egg samples, with median concentrations ranging from 0.5 to 2.8 ng/g lw. SCCPs dominated in the soil samples (400-21300 ng/g soil organic matter, SOM), except at the official dumpsite where MCCPs were highest (65000 ng/g SOM). Concentrations of dechloranes in soil ranged from below LOD to 240 ng/g SOM, and the dominating compounds were Dechlorane Plus and Dechlorane 603. Risk assessment of CP levels gave margins of exposure (MOE) close to or below 1000 for SCCPs at one location.

The potential health risks of short-chain chlorinated paraffin: A mini-review from a toxicological perspective

Short-chain chlorinated paraffins (SCCPs) are ubiquitously distributed in various environmental matrics due to their wide production and consumption globally in the past and ongoing production and use in some developing countries. SCCPs have been detected in various human samples including serum, milk, placenta, nail, and hair, and internal SCCP levels were found to be positively correlated with biomarkers of some diseases. While the environmental occurrence has been reported in a lot of studies, the toxicity and underlying molecular mechanisms of SCCPs remain largely unknown. The current tolerable daily intakes (TDIs) recommended by the world health organization/international programme on chemical safety (WHO/IPCS, 100 μg/kg bw/d) and the UK Committee on Toxicity (COT, 30 μg/kg bw/d) were obtained based on a no observed adverse effect level (NOAEL) of SCCP from the repeated-dose study (90 d exposure) in rodents performed nearly 40 years ago. Importantly, the health risks assessment of SCCPs in a variety of studies has shown that the estimated daily intakes (EDIs) may approach and even over the established TDI by UK COT. Furthermore, recent studies revealed that lower doses of SCCPs could also result in damage to multiple organs including the liver, kidney, and thyroid. Long-term effects of SCCPs at environmental-related doses are warranted.

Characterization of short-, medium- and long-chain chlorinated paraffins in ambient PM2.5 from the Pearl River Delta, China

Research on the environmental occurrence of long-chain chlorinated paraffins (LCCPs) in ambient fine particulate matter (PM_2.5) is still scarce. In the present study, short-chain chlorinated paraffins (SCCPs), medium-chain chlorinated paraffins (MCCPs) and LCCPs were simultaneously quantified and profiled in PM_2.5 samples collected from 96 primary or secondary schools in the Pearl River Delta of South China. SCCPs, MCCPs and LCCPs were detected in higher than 90% samples with concentrations in the range of 0.832-109, 1.02-110, and 0.173-17.4 ng/m³, respectively. The dominant congener groups of SCCPs, MCCPs and LCCPs were C₁₃Cl_6-8, C₁₄Cl_7-8, and C₁₈Cl_7-9, respectively. The concentrations of SCCPs and MCCPs were higher in summer than in winter, while an opposite seasonal trend was observed for LCCPs. Principal components analysis showed there were seasonal variations in the congener group patterns with C₁₃Cl_6-7 and C₁₄Cl₇ more abundant in summer than in winter_. Concentrations of CPs also exhibited slight spatial variations. Exposure risk assessment based on different age groups suggested exposure to PM_2.5-associated CPs would not pose significant health risk. The present study expands the existing knowledge of CPs contamination in atmospheric environment.

Declining concentrations of chlorinated paraffins in endangered St. Lawrence Estuary belugas (Delphinapterus leucas): Response to regulations or a change in diet?

Very high levels of industrial contaminants in St. Lawrence Estuary (SLE) beluga whales represent one of the major threats to this population classified as endangered under the Species at Risk Act in Canada. Elevated concentrations of short-chained chlorinated paraffins (SCCPs) were recently reported in blubber of adult male SLE belugas. Recent regulations for SCCPs in North America, combined with their replacement by medium- (MCCPs) and long-chained chlorinated paraffins (LCCPs), highlight the importance of tracking this toxic chemical class. The objectives of this study were to evaluate (1) levels and profiles of chlorinated paraffins (CPs) in samples obtained from carcasses of adult male, adult female, juvenile, newborn, and fetus beluga, and (2) trends in adult male belugas between 1997 and 2018. Factors potentially influencing CP temporal trends such as age, feeding ecology and sampling year were also explored. SCCPs dominated (64 to 100%) total CP concentrations across all age and sex classes, MCCPs accounted for the remaining proportion of total CPs, and LCCPs were not detected in any sample. The chlorinated paraffin homolog that dominated the most in beluga blubber was C₁₂Cl₈. Adult male SCCP concentrations from this study were considerably lower (> 2000-fold) than those recently reported in Simond et al. (2020), likely reflecting a previously erroneous overestimate due to the lack of a suitable analytical method for SCCPs at the time. Both SCCPs and total CPs declined over time in adult males in our study (rate of 1.67 and 1.33% per year, respectively), presumably due in part to the implementation of regulations in 2012. However, there is a need to better understand the possible contribution of a changing diet to contaminant exposure, as stable isotopic ratios of carbon also changed over time.

Chlorinated paraffins: A review of sample preparation, instrumental analysis, and occurrence and distribution in food samples

Chlorinated paraffins (CPs) are released into natural environment during processes of production and utilization with diet being the most important exposure route of CPs for human beings. Short-chain chlorinated paraffins (SCCPs) have lower molecular weights, higher vapor pressures, and higher water solubilities than medium-chain chlorinated paraffins (MCCPs) and long-chain chlorinated paraffins (LCCPs), making SCCPs more likely to be readily released into the environment. Thus, SCCPs were enlisted as persistent organic pollutants being included in the Stockholm Convention in 2017. This review article summarized sample preparation and instrumental analysis methods of CPs for food types such as oil, meat, and aquatic foods. In addition, reported concentrations and profiles, dietary intake and risk assessment of CPs in food samples from various regions, such as China, Japan, and Germany are discussed for studies published between 2005 and 2022. This review is timely given the lack of a recent literature summary of the concentration and distribution of CPs in food. All these studies warranted the necessity to maintain continuous monitoring of CPs concentrations and their potential health risks given the concentrations of CPs in food are increasing worldwide.

Dietary Intake Contributed the Most to Chlorinated Paraffin Body Burden in a Norwegian Cohort

Determining the major human exposure pathways is a prerequisite for the development of effective management strategies for environmental pollutants such as chlorinated paraffins (CPs). As a first step, the internal and external exposure to CPs were quantified for a well-defined human cohort. CPs in participants' plasma and diet samples were analyzed in the present study, and previous results on paired air, dust, and hand wipe samples were used for the total exposure assessment. Both one compartment pharmacokinetic modeling and forensic fingerprinting indicate that dietary intake contributed the most to body burden of CPs in this cohort, contributing a median of 60-88% of the total daily intakes. The contribution from dust ingestion and dermal exposure was greater for the intake of long-chain CPs (LCCPs) than short-chain CPs (SCCPs), while the contribution from inhalation was greater for the intake of SCCPs than medium-chain CPs (MCCPs) and LCCPs. Significantly higher concentrations of SCCPs and MCCPs were observed in diets containing butter and eggs, respectively (p < 0.05). Additionally, other exposure sources were correlated to plasma levels of CPs, including residence construction parameters such as the construction year (p < 0.05). This human exposure to CPs is not a local case. From a global perspective, there are major knowledge gaps in biomonitoring and exposure data for CPs from regions other than China and European countries.

Seasonal variation of short-, medium- and long-chain chlorinated paraffin distribution in Belgian indoor dust

Chlorinated paraffins (CPs) are high production volume plasticizers and flame retardants, which have exhibited bioaccumulative and toxic properties. CPs may be released from treated consumer goods and bind with indoor dust, leading to human exposure via unintentional dust ingestion. In this study, the concentrations and homologue distribution of CPs were measured in 50 indoor dust samples collected in paired winter and summer sampling campaigns from 25 homes in Flanders, Belgium. Short-, medium- and long-chain CPs (SCCPs (C_10-13), MCCPs (C_14-17) and LCCPs (C_18-20), respectively) were each detected in all Belgian indoor dust samples with overall median concentrations of 6.1 µg/g (range 0.61 to 120 µg/g), 45 µg/g (range 4.5 to 520 µg/g) and 4.5 µg/g (range 0.3 to 50 µg/g), respectively. Concentrations were significantly higher in the winter samples than summer for each of the three groups (p < 0.05). LCCPs homologues ranging from C_21-32 were also detected in dust samples and accounted for approximately half of the LCCP relative abundance based on instrumental peak area, although a lack of appropriate analytical standards prevented quantification of these homologues. While clear sources of CP contamination in dust could not be identified, significant associations between concentrations of ∑SCCPs, ∑MCCPs and ∑LCCPs (C_18-20) (p < 0.05) suggested the combined application within materials or products in homes. Based on typical exposure scenarios, estimated daily intake of ∑CPs (C_10-20) for adults and toddlers were 14 and 270 ng/kg bw/day, respectively, though margin of exposure assessments for SCCPs and MCCPs indicated that adverse health effects were unlikely for all exposure scenarios. This study presents the first evidence of seasonal variation in the levels and distribution for each of the SCCP, MCCP and LCCP classes in indoor dust and highlights the urgent need for appropriate analytical standards for LCCP quantification.

Tetraphenylphosphonium Chloride-Enhanced Ionization Coupled to Orbitrap Mass Spectrometry for Sensitive and Non-targeted Screening of Polyhalogenated Alkyl Compounds from Limited Serum

Although many types of halogenated compounds are known to bioaccumulate in humans, few are routinely biomonitored and many have remained uncharacterized in human exposome studies due to a lack of high-sensitivity and high-resolution analytical methods. In this study, we discovered tetraphenylphosphonium chloride (Ph₄PCl, 10 μM) as a simple additive to the mobile phase, which enhanced the ionizations of polyhalogenated alkyl compounds (such as organochlorinated pesticides [OCPs], chlorinated paraffins [CPs], dechlorane plus [DPs], and some brominated flame retardants [BFRs]) in the form [M + Cl]^- and boosted mass spectrometry responses by an average of 1-3 orders of magnitude at a resolution of 140,000. Ph₄PCl-enhanced ionization coupled with a halogenation-guided screening process was used to establish a sensitive and non-targeted method that required only single-step sample preparation and identified Cl- and/or bromine-containing alkyl compounds. The method enabled the identification of ∼700 polyhalogenated compounds from 200 μL of human serum, 240 of which were known compounds: 33 short-chain CPs, 52 median-chain CPs, 97 long-chain CPs, 22 very short-chain CPs (vSCCPs), 19 OCPs, 13 DPs, and 4 BFRs. We also identified 325 emerging contaminants (34 unsaturated CPs, 285 chlorinated fatty acid methyl esters [CFAMEs], and 6 chloro-bromo alkenes) and 130 new contaminants (114 oxygen-containing CPs, 2 hexachlorocyclohexane structural analogs, and 11 amino-containing and 3 nitrate-containing chlorinated compounds). The full scan results highlighted the dominance of CPs, CFAMEs, vSCCPs, and dichlorodiphenyltrichloroethanes in the serum samples. Ph₄PCl-enhanced ionization enabled the sensitive and non-targeted identifications of polyhalogenated compounds in small volumes of biological fluid.

Global Historical Production, Use, In-Use Stocks, and Emissions of Short-, Medium-, and Long-Chain Chlorinated Paraffins

The last few decades have seen ubiquitous and increasing contamination of chlorinated paraffins (CPs) worldwide. Here, we develop the first global inventories of production, use, in-use stocks, and emissions of total CPs, including the short-, medium- and long-chain components (SCCPs, MCCPs, and LCCPs) during 1930-2020 using a dynamic substance flow analysis model named Chemical in Products Comprehensive Anthroposhpheric Fate Estimation. The model estimates that a total of ∼33 million metric tons of CPs have been produced and used globally, ∼40% of which still resided in in-use products by 2020 and is available for long-term emissions in the next decades. Global cumulative emissions of CPs have increased to ∼5.2 million metric tons by 2020, with SCCPs, MCCPs, and LCCPs accounting for ∼30, 40, and 30%, respectively. While the production, use, and emissions of CPs started declining in regions such as Western Europe, they remain high in China. The model also suggests that homologues with 10, 14, and 22-23 carbons were predominant in the cumulatively produced and emitted SCCPs, MCCPs, and LCCPs, respectively. The emission estimates were evaluated by generating environmental concentrations that are comparable to literature-reported environmental monitoring data. Our estimates provide opportunities to link the environmental fate and occurrence of CPs to emission sources and lay the basis for future risk-reduction strategies of CPs around the world.

Critical review on disposition of chlorinated paraffins in animals and humans

Even though the chlorinated paraffins (CPs) have been on the environmental pollution agenda throughout the last 50 years it is a class of chemicals that only now is discussed in terms of an emerging issue with extensive annual publication rates. Major reviews on CPs have been produced, but a deeper understanding of the chemical fate of CPs, including formation of metabolites in animals and humans, is still missing. Thus, the present review aims to critically compile our present knowledge on the disposition, i.e. Adsorption, Disposition, Metabolism, and Excretion (ADME) of CPs in biota and to identify research needs. We conclude that CPs could be effectively absorbed from the gastro-intestinal tract (GI) tract, and probably also from the lungs, and transported to various organs. A biphasic elimination is suggested, with a rapid initial phase followed by a terminal phase, the latter (e.g., fat tissues) covering half-lives of weeks and months. CPs are metabolized in the liver and excreted mainly via the bile and faeces, and the metabolic rate and type of metabolites are dependent on chlorine content and chain length. Results that strengthen CP metabolism are in vivo findings of phase II metabolites in bile, and CP degradation to carbon fragments in experimental animals. Still the metabolic transformations of CPs are poorly studied, and no metabolic scheme has yet been presented. Further, toxicokinetic mass balance calculations suggest that a large part of a given dose (not found as parent compound) is transformation products of CPs, and in vitro metabolism studies present numerous CP metabolites (e.g., chloroalkenes, chlorinated ketones, aldehydes, and carboxylic acids).

Short- and medium-chain chlorinated paraffins in commercial complementary baby food produced in different European countries: Occurrence, congener group profiles, portion-based dietary intake, and risk assessment

This study was performed to evaluate the presence of chlorinated paraffins (CPs) in complementary baby food from different European countries, to assess portion-based dietary intake of CPs, and to characterize possible risks to children arising from CPs uptake. In total, 86 baby food samples from 22 countries were grouped into eight food-type categories considering the WHO classification. In six out of eight sample categories, predominance of medium-chain CPs (MCCPs) concentrations over short-chain CPs (SCCPs) was observed and, contrary to expectations, samples that contained ingredients of animal origin (e.g., meat or fish) did not display elevated CPs levels. The median ∑_CPs concentrations for selected sample categories ranged from 0.8 ng g^-1 for desert to 2.8 ng g^-1 found in dry cereal and porridge subgroups, while the highest CPs concentration of 387 ng g^-1 was observed in dry porridge. Among the selected groups of baby foods, portion-based intake of ∑_CPs varied from 1.0 to 43.6 ng kg^-1 body weight (b.w.) while exposure estimations indicated that portion-based dietary exposure through consumption of complementary baby food was the highest for infants aged 3-12 months due to the lower body weight. The risk characterization according to the European Food Safety Authority (EFSA) approach showed that the margin of exposure (MOE) figures higher than the critical value for ∑_CPs, indicating that the dietary exposures through consumption of complementary baby food are unlikely to be of significant health concern for children. However, it should be pointed out that the performed risk assessment covered only SCCPs and MCCPs, while the occurrence of other groups from CPs and CPs related compounds (e.g., very short-chain CPs, chlorinated alkenes, or long-chain CPs (LCCPs)) was not addressed.

Identifying emerging environmental concerns from long-chain chlorinated paraffins towards German ecosystems

Germany is one of several major European producers of chlorinated paraffins (CPs). This study showed that not only the legacy short-chain products (SCCPs, C_10-13), but also the current-use medium- and long-chain products (MCCPs, C_14-17; LCCPs, C_>17) as well as the very-short-chain impurities (vSCCPs, C_<10) are ubiquitous in the 72 samples collected from the coastal, terrestrial, and freshwater ecosystems across the country. The concentrations of LCCPs surpassed those of the other CPs in 40% of the biota samples. Archived bream samples collected downstream of a CP-manufacturing factory showed decreasing temporal trends of (v)SCCPs and relatively constant levels of MCCPs from 1995 to 2019; however, the overall levels of LCCPs have increased by 290%, reflecting the impact of chemical regulation policies on changes in CP production. A visualization algorithm was developed for integrating CP results from various matrices to illustrate spatial tendencies of CP pollution. Higher levels of (v)SCCPs were indicated in the former West Germany region, while MCCP and LCCP concentrations did not seem to differ between former East and West Germany, suggesting relatively equal production and use of these chemicals after the German Reunification. The results provide an early warning signal of environmental concerns from LCCPs on the eve of their booming global production and use.

Chlorinated paraffins - A historical consideration including remarks on their complexity

Chlorinated paraffins (CPs) are high production volume chemicals currently produced and used in higher quantities than any other medium-size polyhalogenated compound (class). In addition, the composition of industrial CP mixtures is highly complex and poorly understood. In this article, we searched in the literature for the beginning of the chlorination of alkanes and how this substance class developed from niche applications to unmatched quantities in various industrial applications. Also, an estimation was made on the theoretical variety of chloroparaffins and the possible complexity of industrial CP mixtures. These data may explain why little is known about CPs although the production volume throughout the industrial generation was virtually always higher than the one of PCBs and has continued to increase after the ban of the latter.

Inventory approach for short-chain chlorinated paraffins for the Stockholm Convention implementation in Brazil

Chlorinated paraffins (CPs) are chemicals with multipurpose applications. Their global production has increased despite their adverse impacts on the environment and human health. In 2017, short-chain chlorinated paraffins (SCCPs) were listed as persistent organic pollutants (POPs) in the Stockholm Convention. Yet, specific exemptions were granted for their applications despite the recycling prohibition for products containing SCCPs. Therefore, we aimed to produce the first Brazilian inventory of SCCPs following its respective guidance to evaluate the applicability of the SCCP inventory guidance and to provide technical insights regarding SCCPs in the update of the Brazilian National Implementation Plan (NIP). Moreover, we performed a review of SCCP occurrence in Brazil to fulfil data gaps in the inventory development. We identified and consulted nationwide stakeholders and assessed foreign trade data of CPs and products that might contain CPs in relevant amounts. The Brazilian production of CPs was discontinued in 1994. However, CPs are still imported and used in the country. CPs have been mostly applied as plasticizers, flame retardants and lubricants in Brazil. The import of products containing CPs also pose a significant route of CP entrance into Brazil. Thus, the current end-of-life management of CP-containing products is a bottleneck towards the Convention implementation. The guidance application was feasible and useful despite the low engagement of stakeholders. To assess foreign trade of CPs and CP-containing products, we recommend the use of more specific tracking codes. Besides, the review of SCCP occurrence is not a demanded part for an inventory but was a useful complementation.