Identification of the Released and Transformed Products during the Thermal Decomposition of a Highly Chlorinated Paraffin

Characterizing organophosphate esters and chlorinated paraffins in surface soils affected by diverse e-waste disassembling process in South China: Occurrence, distinct emission, and risk assessment

E-waste recycling activities are a crucial emission source of organic pollutants, posing potential risks to the surrounding environment and human health. To understand the potential impact related to diverse e-waste dismantling activities, we investigated two categories of popular flame retardants (i.e., organophosphate esters (OPEs) and chlorinated paraffins (CPs) and their resultant possible ecological risk in 53 surface soil samples from Qingyuan, a well-known e-waste recycling region in South China. Varied concentrations of ΣOPEs (20.5-8720 ng/g) and ΣCPs (920-16800 ng/g) were observed at diverse dismantling sites, while relatively low levels of ΣOPEs (6.13-1240 ng/g) and ΣCPs (14.8-2870 ng/g) were found in surrounding soils. These results indicated that primitive e-waste dismantling processes were the primary emission source of OPEs and CPs in the studied area, with e-waste dumping and manual dismantling being the most important emission sources for OPEs and CPs. More importantly, CPs could be degraded/transformed into more toxic intermediates via dechlorination and decarbonization during the burning of e-waste. Furthermore, our results indicated the potential ecological risks posed by OPEs and CPs related to e-waste recycling.

Intercorrelations of Chlorinated Paraffins, Dechloranes, and Legacy Persistent Organic Pollutants in 10 Species of Marine Mammals from Norway, in Light of Dietary Niche

Short-, medium-, and long-chain chlorinated paraffins (CPs) (SCCPs, MCCPs, and LCCPs) and dechloranes are chemicals of emerging concern; however, little is known of their bioaccumulative potential compared to legacy contaminants in marine mammals. Here, we analyzed SCCPs, MCCPs, LCCPs, 7 dechloranes, 4 emerging brominated flame retardants, and 64 legacy contaminants, including polychlorinated biphenyls (PCBs), in the blubber of 46 individual marine mammals, representing 10 species, from Norway. Dietary niche was modeled based on stable isotopes of nitrogen and carbon in the skin/muscle to assess the contaminant accumulation in relation to diet. SCCPs and dechlorane-602 were strongly positively correlated with legacy contaminants and highest in killer (Orcinus orca) and sperm (Physeter macrocephalus) whales (median SCCPs: 160 ng/g lw; 230 ng/g lw and median dechlorane-602: 3.8 ng/g lw; 2.0 ng/g lw, respectively). In contrast, MCCPs and LCCPs were only weakly correlated to recalcitrant legacy contaminants and were highest in common minke whales (Balaenoptera acutorostrata; median MCCPs: 480 ng/g lw and LCCPs: 240 ng/g lw). The total contaminant load in all species was dominated by PCBs and legacy chlorinated pesticides (63-98%), and MCCPs dominated the total CP load (42-68%, except 11% in the long-finned pilot whale Globicephala melas). Surprisingly, we found no relation between contaminant concentrations and dietary niche, suggesting that other large species differences may be masking effects of diet such as lifespan or biotransformation and elimination capacities. CP and dechlorane concentrations were higher than in other marine mammals from the (sub)Arctic, and they were present in a killer whale neonate, indicating bioaccumulative properties and a potential for maternal transfer in these predominantly unregulated chemicals.

Short- and medium-chain chlorinated paraffins in breast milk in Shanghai, China: Occurrence, characteristics, and risk assessment

As novel contaminants, short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) have been of great concern in the past several years. Shanghai was one of the provinces with the largest chlorinated paraffins (CPs) emission in China; nevertheless, there is currently little information on the human exposure to SCCPs and MCCPs, particularly MCCPs. In this study, 25 breast milk samples were collected in Shanghai from 2016 to 2017. The concentrations of SCCPs and MCCPs were determined using two-dimensional gas chromatography coupled with orbitrap high-resolution mass spectrometry (GC × GC-orbitrap-HRMS) to investigate their characteristics and assess the associated health risks for breast-fed infants. Compared with the previous studies in other areas, the current study presented the higher CPs concentrations, with median concentrations of SCCPs and MCCPs up to 771 and 125 ng/g lipid weight (lw), respectively. The exposure profiles of the CPs were characterized by C10 and Cl6-7 as the predominant congeners of SCCPs, while C14 and Cl7-9 were identified as the dominant groups of MCCPs. CP-42 and CP-52 were identified as potential sources of CPs found in breast milk samples collected in Shanghai. The concentrations of MCCPs exhibited a positive correlation (p value < 0.05) with the dietary consumption of meat and poultry. No significant positive correlations were observed for SCCPs and MCCPs with polychlorinated dibenzodioxins/furans (PCDD/Fs) congeners. A preliminary exposure assessment showed that SCCPs in breast milk potentially posed high risks to the breast-fed infants in Shanghai.

Polychlorinated Naphthalenes in Foods from the French Market: Occurrence, Dietary Exposure, and Evaluation of Relative Contributions to Dioxin-like Contaminants

Despite the growing interest in PCNs and the dioxin-like toxicity exhibited by a number of congeners, a comprehensive assessment of their contribution to the cocktail of dioxin-like contaminants is still lacking. To address such a shortcoming, this study investigated the PCN contamination in foodstuffs recently acquired in France, together with that of the regulatory polychlorinated dibenzodioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs). PCNs were ubiquitous at levels (∑70 PCNs = 2.5-150 pg g-1 wet weight) similar to those reported in other countries, with maximum concentrations observed in fish and fishery products from the North-East Atlantic Ocean. Their congener patterns further suggested unintentional releases of PCNs, while those of the other foodstuffs were correlated to the historical PCN profiles. Low risk from dietary exposure was estimated (∑70 PCNs-EDIs of 60-360 pg kg-1 bw d-1, ∑24 PCNs-TEQ-EDIs of 8 × 10-3-2.2 × 10-2 pg TEQ kg-1 bw d-1), with milk and dairy products being the highest contributors, followed by meat and meat products. Finally, the rather high contributions of PCNs to the total PCNs+PCDD/Fs+PCBs concentrations (0.9-50%, average of 9%) and the toxic equivalents (0.2-24%, average of 5%) show that these substances are not minor components of the PCNs+PCDD/Fs+PCBs cocktail.

Occurrence and Formation Mechanism of PCDD/Fs and SCCPs in Chlorinated Paraffin Products

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and short-chain chlorinated paraffins (SCCPs) can be formed during the production of chlorinated paraffins (CPs). Detection and accurate quantification of PCDD/Fs in CPs are challenging because of their matrix complexity. Therefore, the occurrence and formation mechanisms of PCDD/Fs from CPs have not been studied extensively in the past. In this study, 15 commercial samples including solid and liquid CPs were collected in 2022 from China. The average ΣSCCP concentrations detected in the solid and liquid CPs were 158 and 137 mg/g, respectively. The average International Toxic Equivalent (I-TEQ) values of 2,3,7,8-PCDD/F in solid and liquid CPs were 15.8 pg I-TEQ/g and 15.0 pg I-TEQ/g, respectively. The solid and liquid CPs had different predominant congener groups for SCCPs and PCDD/Fs. Possible formation routes for the generation of PCDD/Fs were analyzed by screening precursors in paraffin and laboratory-scale thermochemical experiments of CPs. The transformation between 2,3,7,8-PCDD/Fs and non-2,3,7,8-PCDD/Fs was recognized by calculating the successive chlorination preference. The first reported occurrence of PCDD/Fs in CP commercial products indicated that exposure to CPs and downstream products might be an assignable source of PCDD/F emission, which is of great significance to further explore the control factors of PCDD/Fs in the whole life cycle of CPs.

Release Mechanism of Short- and Medium-Chain Chlorinated Paraffins from PVC Materials under Thermal Treatment

Chlorinated paraffins (CPs) as plasticizers are massively added to polyvinyl chloride (PVC) products, during whose life cycle CPs can be continuously released especially under thermal stress. In this study, a PVC cable sheath was adopted as a representative kind of PVC material to investigate the release behaviors of short- and medium-chain CPs (SCCPs and MCCPs) under thermal treatment. Release percentages of CPs with increasing temperature followed a Gaussian-like curve. At the unmolten stage of 80 °C, heating for 10 min caused 0.051% of added SCCPs and 0.029% of added MCCPs to be released. At the molten stage of 270 °C, accumulative release rates of SCCPs and MCCPs within 10 min were up to 30 and 14%, respectively. The developed emission model indicated that material-gas partitioning and internal diffusion simultaneously governed the release of CPs. During thermal treatment, the release of CPs could be remarkably affected by the thermal expansion of the PVC material and the formation of breakage and micropores. Congener group profiles of released CPs indicated a slight fractionation effect for SCCPs during the release process. Furthermore, the release risk of CPs from the whole life cycle of PVC products was preliminarily evaluated.

A review of the mechanisms of by-product PCB formation in pigments, dyes and paints

There has been an increased awareness of paints and pigments as a source of by-product PCBs in the environment. The majority of existing work has focused only on reporting the presence of the main PCBs in different products with a specific focus on the most PCB congeners, PCB11 and PCB209. This gives the impression that only a handful of PCBs are found in paints. However, this is not the case. PCB profiles in paints and pigments can be just as complex as commercial technical mixtures. This review identified the presence of 149 different PCBs in paint samples. For reference, only 141 different PCBs have been reported in all of the 5 main commercial Aroclor formulations (A1016, A1242, A1248, A1254 (early & late) and A1260). The total PCB concentrations in some paint samples can be substantial, with concentrations as high as 919 mg kg^-1 reported in azo pigments. When trying to identify sources of PCBs in the environment, pigments, dyes and paints are often overlooked. In this manuscript, we have compiled congener profiles from 140 different samples from the available scientific literature and presented this in the supplementary information as valuable resource for others to use in source identification applications. We have also proposed detailed mechanisms for the formation of PCBs in pigments, dyes and paints. In many cases, the PCB congeners predicted by these mechanisms provide an excellent match for what has been observed in the scientific literature. We have also identified several additional classes of pigments that are expected to contain PCBs but have yet to be verified by experimental data.

Medium- and long-chain chlorinated paraffins in air: A review of levels, physicochemical properties, and analytical considerations

Chlorinated paraffins (CPs) are synthetic chemicals that are produced at high volumes and have a global presence. CPs are generally divided into three groups based on their carbon chain lengths: short-chain CPs (SCCPs, C_10-13), medium-chain CPs (MCCPs, C_14-17), and long-chain CPs (LCCPs, C_≥18). SCCPs have been formally recognized as persistent organic pollutants (POPs) and have been listed under the Stockholm Convention on POPs. Concerns about increases in MCCP and LCCP production as replacements for SCCP products are rising, given their similar properties to SCCPs and the fact that they remain relatively understudied with only a few reported measurements in air. Passive air samplers with polyurethane foam disks (PUF-PAS), which have been successfully applied to SCCPs, provide an opportunity to expand the existing body of data on MCCP and LCCP air concentrations, as they are inexpensive and require little maintenance. The uptake of MCCPs and LCCPs by PUF disk samplers is characterized in this paper based on newly derived PUF-air partitioning coefficients using COSMOtherm. The ability of PUF disk samplers to capture both gas-phase and particle fractions is important because MCCPs and LCCPs have reduced volatility compared to SCCPs and therefore are mainly associated with particulate matter in air. In addition, due to their use as additives in plastics and rubber products, they are associated with micro- and nanoplastics, which are considered to be potential vectors for the long-range atmospheric transport (LRAT) of these chemicals. The review has highlighted other limitations to reporting of MCCPs and LCCPs in air, including the lack of suitable analytical standards and the requirement for advanced analytical methods to detect and resolve these complex mixtures. Overall, this review indicates that further research is needed in many areas for medium- and long-chain chlorinated paraffins in order to better understand their occurrence, transport and fate in air.

Biotic and Abiotic Transformation Pathways of a Short-Chain Chlorinated Paraffin Congener, 1,2,5,6,9,10-C10H16Cl6, in a Rice Seedling Hydroponic Exposure System

In this work, a typical congener of short-chain chlorinated paraffins (SCCPs) with six chlorine atoms (CP-4, 1,2,5,6,9,10-C₁₀H₁₆Cl₆, 250 ng/mL) was selected to elaborate the comprehensive environmental transformation of SCCPs in rice seedling exposure system. CP-4 was quickly absorbed, translocated, and phytovolatilized by seedlings with a small quality of CP-4 (5.81-36.5 ng) being detected in the gas phase. Only 21.4 ± 1.6% of an initial amount (10,000 ng) of CP-4 remained in the exposure system at the end of exposure. Among the transformed CP-4, some were attributed to the degradation of the rhizosphere microorganism (9.1 ± 5.8%), root exudates (2.2 ± 4.2%), and abiotic transformation (3.0 ± 2.8%) that were proved by several transformation products found in the root exudate exposure groups and unplanted controls, and a majority was phytotransformed by rice seedlings. Here, 61 products were determined through complex transformation pathways, including multihydroxylation, -HCl elimination, dechlorination, acetylation, sulfation, glycosylation, and amide acid conjugation. The acetylated and amide acid conjugates of CPs were first observed. Phase I and Phase II phytometabolic reactions of CPs were found intertwining. These findings demonstrate that multiactive transformation reactions contribute to the overlook of CPs accumulated in plants and are helpful for the environmental and health risk assessments of SCCPs in agricultural plants.

Environmental occurrence and remediation of emerging organohalides: A review

As replacements for "old" organohalides, such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), "new" organohalides have been developed, including decabromodiphenyl ethane (DBDPE), short-chain chlorinated paraffins (SCCPs), and perfluorobutyrate (PFBA). In the past decade, these emerging organohalides (EOHs) have been extensively produced as industrial and consumer products, resulting in their widespread environmental distribution. This review comprehensively summarizes the environmental occurrence and remediation methods for typical EOHs. Based on the data collected from 2015 to 2021, these EOHs are widespread in both abiotic (e.g., dust, air, soil, sediment, and water) and biotic (e.g., bird, fish, and human serum) matrices. A significant positive correlation was found between the estimated annual production amounts of EOHs and their environmental contamination levels, suggesting the prohibition of both production and usage of EOHs as a critical pollution-source control strategy. The strengths and weaknesses, as well as the future prospects of up-to-date remediation techniques, such as photodegradation, chemical oxidation, and biodegradation, are critically discussed. Of these remediation techniques, microbial reductive dehalogenation represents a promising in situ remediation method for removal of EOHs, such as perfluoroalkyl and polyfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs).

Short- and medium-chain chlorinated paraffins in human blood serum of Czech population

Short- and medium-chain chlorinated paraffins (SCCPs; MCCPs) are widespread environmental pollutants with bioaccumulation potential and adverse effects on human health. The analysis of blood serum is an important strategy to assess the human exposure to various contaminants, including SCCPs and MCCPs. Lately, the information about the exposure of Chinese population has been reported; nevertheless, data on human exposure to SCCPs and MCCPs outside East Asia are still very limited. In this pilot study, SCCPs and MCCPs were determined in 27 serum samples obtained from Czech adults. The samples were extracted by a three-step extraction (repeated with a clean solvent) by a mixture of n-hexane:diethyl ether (9:1, v/v) with subsequent clean-up on Florisil® solid phase extraction column. Gas chromatography coupled with high resolution mass spectrometry operated in negative chemical ionisation was employed for the instrumental analysis. The method recoveries ranged from 71 to 89% with repeatabilities of <20% (expressed as relative standard deviation). In the samples, SCCP concentrations were in the range of <150-2600 ng/g lipid weight, lw (median 370 ng/g lw) and the MCCP concentrations were in the range of <200-2110 ng/g lw (median 360 ng/g lw), respectively. To the best of our knowledge, our reported results are the first data about chlorinated paraffins in human blood serum in Europe, showing exposure to these compounds with yet to be studied effects on human health.

Transformation pathways of chlorinated paraffins relevant for remediation: a mini-review

In the past decades, the environmental presence and ecological risks of chlorinated paraffins (CPs), an emerging class of organic halogen compounds, have been receiving increasing attention worldwide. Short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) constitute the important CPs of considerable concern. In this review article, the state-of-the-art research status on the environmental transformation of CPs, including thermal decomposition, photolytic and photocatalytic degradation, biological metabolism, and atmospheric transformation, was summarized and integrated in detail. The degradation efficiency and transformation products of CPs in these environmental processes were evaluated, in which dechlorination was considered as the major reaction pathway. Notably, waste incineration of CPs has been demonstrated to generate a variety of persistent chlorinated aromatic hydrocarbons such as polychlorinated biphenyls and polychlorinated naphthalenes, which have more significant environmental impacts. Additionally, photodegradation and photocatalysis are suggested as the feasible techniques for efficient removal of SCCPs from water matrices. Overall, the current transformation studies of CPs could facilitate the comprehensive understanding of their environmental behaviors and fate as well as the development of promising remediation strategies for pollution control.

Metabolism of SCCPs and MCCPs in Suspension Rice Cells Based on Paired Mass Distance (PMD) Analysis

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) are mixtures of complex chemical compounds with intensive usage. They are frequently detected in various environmental samples. However, the interaction between CPs and plants, especially the biotransformation behaviors of CPs within plants, is poorly understood. In this study, 1,2,5,6,9,10-hexachlorodecane (CP-4, a typical standard of individual SCCP congeners) and 52%-MCCP (a commercial mixture standard of MCCPs with 52% chlorine content by mass) were selected as representative chemicals to explore the metabolic behaviors of SCCPs and MCCPs using suspension rice cell culture exposure systems. Both 79.53% and 40.70% of CP-4 and 52%-MCCP were metabolized by suspension rice cells, respectively. A complementary suspected screening strategy based on the pair mass distances (PMD) analysis algorithm was used to study the metabolism of CPs mediated by the plant cells. Forty and 25 metabolic products for CP-4 and 52%-MCCP, respectively, were identified, including (multi-) hydroxylation, dechlorination, -HCl- elimination metabolites, (hydroxylation-) sulfation, and glycosylation conjugates. Here, we propose a comprehensive metabolic molecular network and provide insight on degradation pathways of SCCPs and MCCPs in plants for the first time, aiding in further understanding of the transformation behaviors of CPs.

Chlorines Are Not Evenly Substituted in Chlorinated Paraffins: A Predicted NMR Pattern Matching Framework for Isomeric Discrimination in Complex Contaminant Mixtures

Chlorinated paraffins (CPs) can be mixtures of nearly a half-million possible isomers. Despite the extensive use of CPs, their isomer composition and effects on the environment remain poorly understood. Here, we reveal the isomeric distributions of nine CP mixtures with single-chain lengths (C14/15) and varying degrees of chlorination. The molar distribution of C n H2n+2-m Cl m in each mixture was determined using high-resolution mass spectrometry (MS). Next, the mixtures were analyzed by applying both one-dimensional 1H, 13C and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. Due to substantially overlapping signals in the experimental NMR spectra, direct assignment of individual isomers was not possible. As such, a new NMR spectral matching approach that used massive NMR databases predicted by a neural network algorithm to provide the top 100 most likely structural matches was developed. The top 100 isomers appear to be an adequate representation of the overall mixture. Their modeled physicochemical and toxicity parameters agree with previous experimental results. Chlorines are not evenly distributed in any of the CP mixtures and show a general preference at the third carbon. The approach described here can play a key role in understanding of complex isomeric mixtures such as CPs that cannot be resolved by MS alone.

Chlorinated Paraffins in Human Milk from Urban Sites in China, Sweden, and Norway

Short-, medium-, and long-chain chlorinated paraffins (SCCPs, MCCPs, and LCCPs) were analyzed in human milk from the Yangtze River Delta (YRD) and Scandinavia. Individual samples were collected from Shanghai, Jiaxing, and Shaoxing (China), Stockholm (Sweden), and Bodø (Norway) between 2010 and 2016. Mean concentrations (range) of SCCPs, MCCPs, and LCCPs in samples from the YRD were 124 [ Collapse

Key Words Collapse

MESH Headings

• China
• Environmental Monitoring
• Humans
• Hydrocarbons, Chlorinated
• Infant
• Milk, Human
• Norway
• Paraffin
• Sweden

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Affiliation(s)

Yihui Zhou State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
Bo Yuan Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
Elisabeth Nyberg Department of Contaminants, Swedish Environmental Protection Agency, Virkesvägen 2, SE-106 48 Stockholm, Sweden
Ge Yin Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden Shimadzu Scientific Instrument Company, Shanghai 200233, China
Anders Bignert Department of Environmental Monitoring and Research, Swedish Museum of Natural History, Box 50007, SE-104 15 Stockholm, Sweden
Anders Glynn Department of Biomedical Science and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), Box 7028, SE-75007 Uppsala, Sweden
Jon Øyvind Odland Faculty of Health Sciences, Norwegian University of Science and Technology, Postboks 8905, N-7491 Trondheim, Norway
Yanling Qiu Key Laboratory of Yangtze River Water Environment (Ministry of Education), College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Yajie Sun State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Yongning Wu NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, China
Qianfen Xiao State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Daqiang Yin Key Laboratory of Yangtze River Water Environment (Ministry of Education), College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Zhiliang Zhu Key Laboratory of Yangtze River Water Environment (Ministry of Education), College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Jianfu Zhao State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Åke Bergman State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden Department of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden

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Transformation of 1,1,1,3,8,10,10,10-octachlorodecane in air phase increased by phytogenic volatile organic compounds of pumpkin seedlings

Short chain chlorinated paraffins (SCCPs) are widely distributed persistent organic pollutants (POPs). Airborne chlorodecanes were hypothesized to be transformed by reactive phytogenic volatile organic compounds (PVOCs) in our previous work. To test this hypothesis, PVOCs of pumpkin (Cucurbita maxima x C. moschata) were collected and reacted with 1,1,1,3,8,10,10,10-octachlorodecane in the air phase of a sealed glass bottle under illumination for 10 days (reaction system I, simulating atmospheric reaction conditions with PVOCs). The reaction control group (reaction system II) was set at the same conditions but only had chlorodecane (without PVOCs) inside the bottle. Transformation of SCCPs in the air phase of reaction control group was unexpectedly found. Results showed that 1,1,1,3,8,10,10,10-octachlorodecane was transformed to a great extent to C₁₀Cl_5-8, C₉Cl_6-8, and C₈Cl_7-8 in the air phase after 10-d illumination in both with and without the presence of PVOCs, which is explained by carbon chain decomposition, dechlorination and chlorine rearrangement products of the parent SCCP. Those transformation processes were increased to some extent by the PVOCs from pumpkin seedlings. This study provides the first experimental data on atmospheric transformation of SCCPs and also the first evidence that plant emissions (PVOCs) can increase the transformation of SCCPs in air under light and experimental conditions. It provides new insight into the potential transformation and fate of CPs in the environment.

Shorter than short-chain: Very short-chain chlorinated paraffins (vSCCPs) found in wildlife from the Yangtze River Delta

Very short-chain chlorinated paraffins (vSCCPs, C_6-9) occurred in 94% of wildlife samples from the Yangtze River Delta (YRD), China, with C_nCl_m comparable to that of a local CP product, CP-52. Therefore, we determined the content of vSCCPs in CP-52 using a mathematical deconvolution technique. Then with CP-52 and several other reference standards, vSCCPs together with short-, medium-, and long-chain CPs were quantified in 21 wildlife species from an artificial wetland ecosystem and a freshwater ecosystem in the YRD. Concentrations of vSCCPs ranged from 2.6 to 8400 ng/g lipid. These concentrations were 1.2-380 fold lower than SCCPs, but were significantly correlated with those of SCCPs. vSCCP concentrations were comparable to or higher than reported for brominated flame retardants in the same samples. Bioaccumulation tendency of vSCCPs was identified in two benthic species, indicating congener-specific accumulation of vSCCPs in the environment.

Carbon Chain Decomposition of Short Chain Chlorinated Paraffins Mediated by Pumpkin and Soybean Seedlings

Short chain chlorinated paraffins (SCCPs) are a group of complex emerging persistent organic pollutants. In this study, the uptake, translocation, and transformation of four constitutionally defined SCCP isomers were studied using whole pumpkin ( Cucurbita maxima × C. moschata) and soybean ( Glycine max L. Merrill) seedlings via hydroponic exposure. Results showed that the daughter SCCPs were C10Cl5-8 and C11-13Cl5-6. The metabolic transformation of all tested isomers included dechlorination and chlorine rearrangement. In addition, carbon chain decomposition products were found for isomers with trichlorinated carbon atoms (CCl3-groups) in both pumpkin and soybean seedlings. This study provides the first evidence of carbon chain decomposition of SCCPs in whole plants, and it suggests new metabolism pathways of SCCPs in the environment. The influence of carbon chain length and degree of chlorination of SCCPs on their fate and behavior within different plant species were also investigated. Bioaccumulation of SCCPs in pumpkin and soybean increased with increasing carbon chain length and degree of chlorination. In comparison, soybean translocated and degraded parent SCCPs faster and to a greater extent than pumpkin, but pumpkin accumulated parent SCCPs to a greater extent than soybean. After 10 days exposure, less than 4% of the initial mass of exposed chemicals remained in solution of exposure groups. The parent chemicals accumulated in roots ranging from 23.6% to 59.9% for pumpkin and 1.98% to 54.5% for soybean and in stems ranging from 0.7% to 3.81% for pumpkin and 0.50% to 2.54% for soybean. These results give new perspectives on the transport, transformation, and fate of SCCPs in the environment.

Methods for trace analysis of short-, medium-, and long-chain chlorinated paraffins: Critical review and recommendations

Many methods for quantifying chlorinated paraffins (CPs) yield only a total concentration of the mixture as a single value. With appropriate analytical instrumentation and quantification methods, more reliable and detailed analysis can be performed by quantifying total concentrations of short-, medium-, and long-chain CPs (SCCPs, MCCPs, and LCCPs), and in the current optimal situation by quantifying individual carbon-chlorine congener groups (C_nCl_m). Sample extraction and clean-up methods for other persistent organochlorines that have been adapted for recovery of CPs must be applied prior to quantification with appropriate quality assurance and quality control to ensure applicability of the methods for SCCPs, MCCPs, and LCCPs. Part critical review, part tutorial, and part perspective, this paper provides practical guidance to analytical chemists who are interested in establishing a method for analysis of CPs in their lab facilities using commercial reference standards, or for expanding existing analysis of total CPs or SCCPs to analysis of SCCPs, MCCPs, and LCCPs, or to analysis of C_nCl_m congener groups.