Chlorinated Paraffin Research Articles

Short- and medium-chain chlorinated paraffin exposure in South Germany: A total diet, meal and market basket study.

Short- and medium-chain chlorinated paraffins (SCCPs, MCCPs) are high-production volume industrial chemicals that have been previously reported to occur in food, packaging material and the environment. This study presents an assessment of dietary exposure for consumers in Southern Germany based on three different sampling approaches: (i) a classical market basket study (n=154), (ii) the analysis of ready-made meals from restaurants (n=10), and (iii) a total diet approach (n=21). In 35% of the samples, CPs were below the method limit of quantification. Highest amounts of SCCPs and MCCPs were found especially in extra virgin olive oils (EVOOs) and fish. Homologue patterns indicated the partial removal of CPs during the refining of (other) edible oils. Ready-made meals contained only low amounts of CPs equal to estimations based on market basket samples. Total diet samples from the same hospital were generally comparable with each other regardless of diet, although vegetarian meal plans with high amounts of cheese and other dairy products contained up to an order of magnitude more CPs than other diets. Taking all approaches into account, calculated daily exposures for adults ranged 35-420ng/kgbw/day for ΣSCCPs and 22-840ng/kgbw/day for ΣMCCPs, which is between one and two orders of magnitude higher than the current dietary intake of polychlorinated biphenyls (indicator PCBs) in Europe.

Protein-affinity guided identification of chlorinated paraffin components as ubiquitous chemicals

Chlorinated paraffins (CPs) have been extensively examined to identify their components. Short-chain CPs with a carbon number of 10–13 have been strictly restricted or banned due to their addition to the list of Persistent Organic Pollutants in the world. However, more constituents with potential toxicities in these complicated mixtures are still unclear. In the present study, a purification method based on the protein affinity of thyroid hormone-related proteins (transthyretin and thyroid receptor) was established. The protein-based affinity extraction coupled with high-throughput scanning successfully discover a new group of chlorinated compounds (CP(O2)) in commercial CP mixtures. The CP(O2)s were purified from the commercial mixtures and identified to be chlorinated fatty acid methyl esters (CFAMEs) with a carbon chain length of 17–19 and 3–11 chlorines by a combination of liquid-liquid extraction, hydrolysis, Fourier transform infrared spectrometry and Orbitrap mass spectrometry. The newly identified CFAMEs were found to be ubiquitous in the environmental matrices, and concentration ratios of ∑CFAMEs/∑CPs ranged from 0.01 to 35 in air, soil and food samples. CFAMEs were also detected in blood samples of general populations, and accumulated in humans through dietary uptake. CFAMEs can compete with T4 for binding TTR with higher potencies than CPs, possibly leading to disruptions of thyroid hormone homeostasis.

Disentangling the contributions of urban and production sources in short- and medium-chain chlorinated paraffin concentrations in a complex source region

Short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were measured in tree bark samples. These samples were collected around a chemical industrial park containing several chlorinated paraffin (CP) production plants, in a nearby city (Zhengzhou), and along a transect between the industrial park and city. Theoretical air concentrations were back-calculated from concentrations in bark using a predictive equation for estimating equilibrium bark-air partition coefficients. We developed this equation from a series of previously published Kbark-air measurements. Comparison of the normalized concentration profiles along south to north transects showed that wind played only a minor role in CP concentrations and profiles in the region. Three distinct source profiles were found in the complex source region. A fingerprint analysis technique was used to quantify the contribution of each source to the CP burden at various locations along the transect. We found that CP profiles at sites up to 6 km from the industrial park were strongly influenced by CP plant emissions, whereas the sites located in the rural zone and rural-urban interface were influenced by a mixture of CP plant emissions and the neighboring city.

Preparation of microencapsulated aluminum hypophosphite and its flame retardancy of the unsaturated polyester resin composites

A novel microencapsulated flame retardant (CP@AHP), aluminum hypophosphite (AHP) as the core material and chlorinated paraffin (CP) as the shell material, was successfully prepared and applied in unsaturated polyester resin (UPR) to prepare the UPR composites in this paper. The aim of microencapsulation AHP was to enhance the fire safety of the UPR composites. The structure, morphology and thermal behavior of CP@AHP were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermogravimetric analysis (TG), respectively. The thermal and flame-retardant properties of the UPR composites were evaluated by TG and cone calorimetry test (CCT), respectively. At the same time, the tensile and flexural properties of UPR composites were tested. Compared with pure UPR, the residue at 800 °C of UPR/CP@AHP-1:2 (UPR/CP@AHP with the mass ratio of CP:AHP = 1:2) under nitrogen atmosphere is from 6.9 to 31.6. The CCT results showed that the peak heat release rate (pHRR) and total heat release of UPR/CP@AHP-1:2 decreased by 58.4 and 46.1%, respectively, in comparison with pure UPR. The results of TG and CCT indicated that CP@AHP could improve the thermal stability and flame retardancy of the UPR composites. Finally, based on the above results, the flame retardancy mechanism of CP@AHP was proposed.

Addressing Main Challenges Regarding Short- and Medium-Chain Chlorinated Paraffin Analysis Using GC/ECNI-MS and LC/ESI-MS Methods.

The risk assessment of chlorinated paraffins (CPs), chemicals of widespread industrial use, is struggling without standardized analytical methods to obtain reliable occurrence data. Indeed, scientists face analytical challenges that hinder the comparability of analytical methods, among them uncontrolled ionization efficiency and lack of quantification standards. In this study, our goal was to investigate potential issues faced when comparing data from different mass spectrometry platforms and quantification methods. First, the injection of the same set of single-chain length standards in three different instrumental mass spectrometry set-ups (liquid chromatography-electrospray-Orbitrap (LC/ESI-HRMS), liquid chromatography-electrospray-time-of-flight (LC/ESI-MS), and gas chromatography-electron capture negative ion-Orbitrap (GC/ECNI-HRMS)) revealed a shift of homologue response patterns even in-between LC/ESI-based set-ups, which was more pronounced for CPs of low chlorination degree. This finding emphasizes the need for a comprehensive description of instrument parameters when publishing occurrence data. Second, the quantification of a data set of samples with four quantification methods showed that quantification at the sum SCCP and MCCP levels presented good comparability, while quantification at the homologue level remained unsatisfactory. In light of those results, we suggest that (i) response pattern comparison should only be performed between similar instrumental set-ups, (ii) experimental chlorination degrees should be used when quantifying according to the %Cl (instead of those provided by the suppliers), and (iii) concentration results should be expressed as the sum of SCCPs and MCCPs primarily, with an indication on the match between samples and quantification standards (for example their chlorine content).

Spatial distributions and homolog profiles of chlorinated nonane paraffins, and short and medium chain chlorinated paraffins in soils from Yunnan, China

To preliminarily investigate the occurrence, spatial distributions, homolog compositions, and ecological risks of chlorinated paraffins (CPs) in Yunnan, China, 110 soil samples were collected from an area part of Yunnan, representative of the whole Yunnan area, where had similar characteristics to most parts of Yunnan and 22 pooled soil samples were analyzed for 50 CP congener groups (C9–17Cl5–10). The chlorinated nonane paraffin (C9-CP), short chain (SCCP), and medium chain chlorinated paraffin (MCCP) concentrations in soil samples were 8–109 ng/g (average 39 ng/g), 79–948 ng/g (average 348 ng/g), and 20–1206 ng/g (average 229 ng/g), respectively. The C9-CP homologs contributed 5%–16% of the C9–13-CP concentrations in soils. No significant correlation was found between CP concentrations and the total organic carbon content (P > 0.05). The CP levels in soils from Yunnan were at a medium level compared with those in other areas worldwide. Human activity and atmosphere deposition would influence the levels and spatial distributions of CPs in this area. The concentrations of CPs in east area were higher than those in west area. C10Cl6–7 were the major SCCP congeners and C14Cl6–7 were the major MCCP congeners. Principal component analysis indicated that SCCPs and MCCPs came from different sources. A preliminary risk assessment indicated that these concentrations of CPs in soil from Yunnan do not pose a significant ecological risk for soil organisms.

Short- and medium-chain chlorinated paraffins in plastic animal feed packaging and factors affect their migration into animal feed

Chlorinated paraffins (CPs) are used as plasticizers and flame retardants in plastics. Plastic packaging containing CPs is widely used for storage of animal feed, which can become contaminated by CPs that migrate into the feed. In the present study, 31 commercial animal feed packaging samples made of polypropylene (PP) or polyethylene (PE) were collected from animal feed manufacturers in China. The mean concentrations of short-chain chlorinated paraffins (SCCPs) in the PP and PE samples were 60.0 and 54.5 μg/g, respectively. The medium-chain chlorinated paraffin (MCCP) mean concentrations in the PP and PE samples were 62.7 and 9.23 μg/g, respectively. The carbon congener group profiles of SCCPs and MCCPs in the samples were different. The dominant SCCP and MCCP chlorine congener groups in all the samples were Cl6–7 and Cl6–8, respectively. Time and temperature influenced the migration of CPs from packaging into animal feed. As the time or temperature increased, the CP concentrations in the animal feed increased but the congener group profiles of the SCCPs and MCCPs in the animal feed did not change. To reduce contamination of animal feed by CPs, it is necessary to restrict the use of CPs in animal feed packaging.

Liquid chromatography–electrospray ionization-tandem mass spectrometry for the determination of short-chain chlorinated paraffins in mixed plastic wastes

Wastes containing short-chain chlorinated paraffins (SCCPs) at concentrations above the Basel Convention low persistent organic pollutant content (LPC) values must be destroyed or irreversibly transformed in an environmentally-sound manner. Here, we developed a novel liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MSMS) method for determining the concentrations of SCCPs in mixed plastic wastes. Major SCCP homologues were identified with good separation and peak width by using a low-hydrophobicity cyano-propyl column and a mobile phase consisting of water and methanol containing ammonium acetate. Precursor ion peaks corresponding to the formation of stable SCCP homologue-adducts were observed, followed by two intense product ion peaks corresponding to separation of the adduct into acetate and the homologue. The formulation of a novel calibration standard with known SCCP homologue percentage composition supported the development of our novel mass spectrometric technique. The results obtained with the LC-ESI-MSMS system were quantitatively and qualitatively comparable with those obtained with a high-resolution mass spectrometry (HRMS) coupled to gas chromatography (GC) system. Homologue concentrations determined by LC-ESI-MSMS were significantly correlated with those determined by GC-HRMS in samples of commercial chlorinated paraffin mixture and mixed plastic waste, respectively. As a complementary technique to the highly accurate, but less versatile GC-HRMS approaches, the SCCP analysis by LC-ESI-MSMS is a practical way to identify mixed plastic wastes containing SCCPs at concentrations higher than the Basel Convention's LPC value.

Tribological properties of DLC coating under lubricated and dry friction condition

Increasing demands on reducing abundant use of environmentally hazardous lubricants like chlorinated paraffin oil in production motivates extensive research on dry friction condition. However, the dry friction condition is not favourable, and it causes high friction and severe wear problems. This paper presents the tribological behaviour of a new hard coating, namely double-layer DLC/TiAlN, deposited onto the tool steel surface via a Physical Vapour Deposition (PVD) process. A pin-on-disk tribometer was used to study the long-term performance of DLC/TiAlN coated tool steel under lubricated and dry friction conditions. Surface damage after the experiment was observed by using a light optical microscope (LOM) and also, analysed by measuring wear scar profiles with a tactile roughness profilometer. The results were compared with uncoated tool steel. Based on the experimental result, applying the DLC/TiAlN coating to the tool steel surface has led to a significant reduction of friction and almost no wear scar was observed. The study proved that the DLC/TiAlN coating contributes to the better wear life of the tool steel, thereby improving the tool lifetime.

Effects of DLC/TiAlN-coated die on friction and wear in sheet-metal forming under dry and oil-lubricated conditions: Experimental and numerical studies

Experimental and numerical analyses were conducted to explore the influence of DLC/TiAlN-coated die surfaces in sheet-metal forming under dry and oil-lubricated conditions. In this study, ironing and deep-drawing experiments were performed to determine the potential of the DLC/TiAlN coating in the sheet forming of stainless steels under different tribological conditions. The performance and physical properties of the DLC/TiAlN-coated die surface were obtained through load, surface roughness, and wear measurements as well as hardness and microstructure examination. The experimental results indicated that the DLC/TiAlN coating strongly resists galling under dry friction and thin film lubrication conditions that reduces the friction and forming load. The presence of a thin oil film reduces the sliding-originated surface tensile stresses of the DLC/TiAlN coating, improving the wear resistance of the die surface even at high temperatures and high contact pressures. Thermomechanical numerical analysis supported the experimental results, which confirmed that the lubricant discharged the heat generated in the die–workpiece contact region to reduce the friction and forming load. With the DLC/TiAlN coating, the plain mineral oil with no extreme pressure additives can function as effective as chlorinated paraffin oil for protecting the die surface, thus extending the die service life.

Characterization of single chain length chlorinated paraffin mixtures with nuclear magnetic resonance spectroscopy (NMR)

Chlorinated paraffins (CPs) are complex mixtures of polychlorinated n-alkanes of different chain length. Despite their environmental relevance, quantification is still a challenge. Moreover, the individual structures of the molecules in technical CP mixtures are largely unknown. Here, we synthesized 21 and studied 29 single chain length CP mixtures ranging from C10- to C17-CPs with different chlorine contents between 41.8% and 62.6% Cl and analyzed them by means of nuclear magnetic resonance spectroscopy (NMR). Discrete ranges of chemical shifts were observed in one-dimensional 1H and 13C NMR spectra. Two dimensional heteronuclear single quantum coherence spectroscopy (HSQC) enabled to assign nine substructures. These measurements also verified the presence of [-CCl2-] groups and chlorine atoms on terminal carbons in highly chlorinated (>59% Cl) mixtures. 1H NMR spectra of different chain length and the same degree of chlorination looked virtually the same. However, with increasing degree of chlorination the observed patterns in the spectra were slightly shifted downfield. Based on these findings, a calculation mode was developed to estimate the chlorine content (%) of the single chain length CP mixtures. The results agreed well (<0.9% mean deviation) with parallel measurements by elemental analysis.

Leather tanning: Life cycle assessment of retanning, fatliquoring and dyeing

Tanneries boost the local economic development, but lead to severe environmental pollution; hence, improving the environmental assessment of this sector is essential. In this paper, the Life Cycle Assessment method was applied to estimate impacts on the environment and human health of retanning, fatliquoring and dyeing. The analysis was performed from a “gate to gate” perspective. Moreover, sulpho chlorinated paraffin and epoxidized vegetable oil have been evaluated as alternative fatliquoring agents.The production of electricity required for the rotation of drums gives the main contribute to most of the impact categories, followed by the azo-dye production. Emissions of sulfur dioxide, nitrogen oxides, manganese, vanadium and nickel associated to power plants are the main sources of terrestrial acidification and particulate matter formation, as well as of human and marine toxicity (4.48·10−1 and 1.09·10−2 kg of 1,4-DBeq kg−1 crust leather, respectively). Nitrate loads from wastewater treatment and oxidative treatments affect heavily marine eutrophication (6.9·10−1 g N eq kg−1 crust leather). The use of epoxidized vegetable oil would affect human toxicity, ecosystem, metal and water resources depletion more than the use of sulpho chlorinated paraffin, mainly due to pesticides distribution and other cultivation practices. Phosphate and nitrate releases due to fertilization determine the high impact on the categories freshwater and marine eutrophication.Progress in increasing the conversion efficiency is demanded, but overall focus must be made on the substitution of fossil fuels with cleaner alternatives. The transition towards a circular economy is encouraged; increasing rates of reduction, reuse, recycle and recover of solid waste and tannery effluents are recommended. Agricultural practices with a reduced consumption of phytosanitary products and mineral fertilizers, alternative to conventional farming, would strongly contribute to increase the sustainability of epoxidized vegetable oil as alternative fatliquoring agent.

Characterization of short- and medium-chain chlorinated paraffins in cereals and legumes from 19 Chinese provinces

Short-chain chlorinated paraffins (SCCPs) were added to the Stockholm Convention Annex A in May 2017. China is the largest producer of chlorinated paraffins (CPs). CPs in the environment can be transferred to foodstuffs directly and through bioaccumulation and then ingested by humans. Cereals and legumes are important components of Chinese diets, so the risks posed by CPs in cereals and legumes should be of concern. 1710 cereal samples and 1710 legume samples from 19 Chinese provinces were pooled by type and province (giving 19 pooled cereal and 19 pooled legume samples). The SCCP and medium-chain chlorinated paraffin (MCCP) concentrations in the samples were determined by comprehensive two-dimensional gas chromatography tandem time-of-flight mass spectrometry (GC × GC-TOFMS). The mean SCCP concentrations in the cereal and legume samples were 343 and 328 ng g−1 wet weight (ww), respectively, and the mean MCCP concentrations were 213 and 184 ng g−1 ww, respectively. The dominant SCCP congener groups were C10Cl6–7 in cereals and C10Cl5–6 in legumes. The MCCP congener groups C14Cl6–7 were dominant in both cereals and legumes. The CP concentrations were higher in samples from eastern China than in samples from other regions. Risk assessments indicated that SCCPs and MCCPs in cereals and legumes do not pose strong risks to Chinese residents.

Bioaccumulation and biomagnification of short-chain chlorinated paraffins in marine organisms from the Pearl River Estuary, South China

Short-chain chlorinated paraffins (SCCPs) are a series of new persistent organic pollutants, posing a risk of significant adverse effects to biota. Increasing attention has been paid to SCCP pollution in China as large amounts of chlorinated paraffin (CP) products containing SCCPs have been produced and used there. However, knowledge of the bioaccumulation of SCCPs in marine organisms from the Pearl River Estuary (PRE), Southern China, is still scarce. In this study, SCCP concentrations were measured in seawater, sediments, and marine organisms from the PRE. SCCP concentrations ranged from 180 to 460 ng/L in seawater, from 180 to 620 ng/g dry weight (dw) in sediments, and from 870 to 36,000 ng/g lipid weight (lw) in marine biota samples. C10–11 SCCPs were the predominant homologues in all the samples, with an average abundance of 68% in seawater, 57% in sediments, and 56–77% in marine organisms. However, chlorine patterns of SCCPs in seawater, sediments, and marine organisms were different. Cl8–10 SCCPs dominated in sediments, whereas Cl5–7 SCCPs were the predominant SCCP homologues in water and most organism species. The logarithm bioaccumulation factors (BAFs) of SCCPs ranged from 1.6 to 3.0, and increased significantly with the increase of Kow values for most marine biota species, indicating that Kow was the major factor controlling the bioaccumulation of SCCPs and that SCCPs with higher lipophilicity were more prone to being bioaccumulated from water. Opposite to that observed for log BAFs, biota-sediment accumulation factors of specific SCCPs (range: 0.01–30) decreased significantly with the increase of Kow values. The biomagnification factor of total SCCPs for oyster–mangrove crab was 2.40, implying the potential biomagnification of SCCPs for benthos in the PRE.

A review of chlorinated paraffin contamination in Arctic ecosystems

Chlorinated paraffins (CPs) present a complex mixture of congeners which are often analysed and assessed as short-, medium- and long-chain CPs, i.e. ΣSCCP (C10–C13), ΣMCCP (C14–C17) and ΣLCCP (≥C18). Their complexity makes the chemical analysis challenging, in particular in terms of accurate quantification, but promising developments involving ultra-high resolution mass spectrometry have been presented lately. Most Arctic data exist for SCCPs, while LCCPs have not yet been studied in the Arctic. ΣSCCP concentrations in Arctic air often exceeded those of ΣMCCP, usually with a predominance of the most volatile C10 congeners, and of banned persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs). The presence of SCCPs and MCCPs in Arctic air, as well as in the Antarctic and in the remote regions of the Tibetan plateau, provides evidence of their long-range transport including sufficient environmental persistence to reach the Arctic. Arctic vegetation accumulated SCCPs partly from air and partly through root uptake from soil, with consequences for the SCCP profile found in Arctic plants. No results have yet been reported for CPs in terrestrial Arctic animals. Results for freshwater sediment and fish confirmed the long-range transport of SCCPs and MCCPs and documented their bioaccumulation. Where additional PCB data were available, ΣPCB was usually higher than ΣSCCP in freshwater fish. Both SCCPs and MCCPs were widely present in marine Arctic biota (e.g. mussels, fish, seabirds, seals, whales, polar bears). In mussels and Atlantic cod, ΣMCCP concentrations exceeded those of ΣSCCP, while this was less clear for other marine species. Marine mammals and the long-lived Greenland shark roughly had ΣSCCP concentrations of 100–500 ng/g lipid weight, often dominated by C11 congeners. Biomagnification appeared to be more pronounced for ΣSCCP than for ΣMCCP, but more studies will be needed. Increasing ΣSCCP concentrations were observed in Arctic air and sediment over time, but not in beluga monitored since the 1980s. For both SCCPs and MCCPs, increasing concentrations over time have been shown in blue mussels and Atlantic cod at some, but not all stations. Indications exist of local sources of SCCPs in the Arctic, including Arctic settlements and research stations. In studies involving multiple locations, a general decrease of SCCP concentrations with increasing latitude or distance from point sources was observed as well as relatively more MCCPs at locations closer to potential CP sources. Monitoring of SCCPs and MCCPs has been initiated in some Arctic regions and will be important to assess the effect of recent regulations of SCCPs and the use of potential replacement chemicals.

Synthesis and characterization of eight single chain length chlorinated paraffin standards and their use for quantification.

Quantification of chlorinated paraffins (CPs) via gas chromatography coupled with electron capture negative ionization low-resolution mass spectrometry (GC/ECNI-MS) is a very common practice, although the quality of the results has been disputed due to insufficient mass resolution and the strong impact of the degree of chlorination on the GC/ECNI-MS response. For further tests we synthesized eight single chain length CP standards (C10 -C17 ) with chlorine contents between 51.1% and 61.3%. The individual single chain length standards, 1 + 1 mixtures of two chain length standards and self-prepared mixtures of short-chain and medium-chain CPs were quantified by linear regression according to a previously reported method (method 1) as well as by exponential regression (method 2). Concentrations obtained from single chain length CP standards deviated between -74% and 152% from the target value. However, the error became smaller when self-prepared CP mixes with two and four chain lengths were analysed. For short-chain CP (SCCP) mixture analysis, both methods produced good results (<25% deviation from the target value). In the case of medium-chain CP (MCCP) mixtures, however, method 2 (17-34% deviation) was more accurate than method 1 (43-52% deviation). Both methods 1 and 2 are fit for GC/ECNI-MS analysis of SCCP mixtures, while the improved method 2 is recommended for quantification of MCCP mixtures.

Determination of short-chain chlorinated paraffins using comprehensive two-dimensional gas chromatography coupled with low resolution mass spectrometry

Short-chain chlorinated paraffins (SCCPs), recently listed as Persistent Organic Pollutants (POPs) under the Stockholm Convention, are contained in commercial chlorinated paraffin (CP) products, which are used in industries such as metalworking fluids, sealants, and textiles. A novel method to determine SCCPs by comprehensive two-dimensional gas chromatography coupled with low resolution mass spectrometry was developed. Calibration curves of response factor versus chlorine content in two chlorine content ranges (R2 were 0.9544 and 0.9736, respectively) were used for quantification of SCCP total concentration. Moreover, relative concentrations of 24 congener groups were also theoretically calculated. Results showed that this method was able to detect SCCP concentration in commercial CP products and urban air samples. SCCP contribution varied largely among different CP products, which is highly determined by carbon chain distribution in paraffins. SCCP concentration in urban air ranged between 12.8–49.1 ng m−3 during nine-month sampling period. The highest SCCP concentration appeared in summer, and the lowest concentration occurred in winter. Gas phase was dominantly occupied by lighter congeners such as C10 group and Cl6 group, while heavier congeners such as C13 group and Cl7 and Cl8 groups contributed more in particle phase.

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

As plasticizers and flame retardants, highly chlorinated paraffin (CP70) and related products will experience thermal processes during their lifecycle stages. However, the thermal transformation data for CP70 is limited. In this study, we investigated the release and transformation of chlorinated and unchlorinated products during the thermal decomposition of CP70. Large quantities of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) and unsaturated analogues (Cl-polyenes or chlorinated olefins) as well as toxic chlorinated aromatic hydrocarbons were formed synergistically under different thermal conditions. The yield of SCCPs increased gradually in the gas phase, while it decreased in the residue at 200-400 °C. SCCPs can be transformed further and generated mostly polychlorinated biphenyls (PCBs). Oxygen promoted the thermal transformation of SCCPs and MCCPs and decreased the yield in the gas phase at >400-500 °C. In contrast, the yield of both SCCPs and MCCPs increased notably under N2 at 800 °C. Chlorobenzene (CBz), PCBs, and polychlorinated naphthalenes (PCNs) were the main chlorinated aromatic hydrocarbons and obtained a maximum yield at 500-600 °C. The present findings indicate that CP70-containing materials may synergistically generate SCCPs, MCCPs, and other toxic chlorinated compounds during their life cycles.

Short-chain chlorinated paraffin (SCCP) pollution from a CP production plant in China: Dispersion, congener patterns and health risk assessment

China is the largest chlorinated paraffin (CP) producer in the world. Given that CP production is a major source of short-chain CP (SCCP) pollution in China, the effects of CP production on the environment inside and outside of CP production plants are worth revealing. The concentrations and specific congener group patterns of SCCPs in various environmental matrices, such as air, soil and dust, inside and outside of a chosen CP production plant surrounded by farmlands and villages were analyzed to explore SCCP pollution and transportation behaviors. SCCP concentrations in air (129–1442 ng/m3) and soil (28–554 μg/g) samples inside the CP production plant were dramatically higher than those in air (91–333 ng/m3) and soil (102–441 ng/g) samples outside the CP production plant. Based on the congener abundance patterns among these samples, lighter groups (C10-11 and Cl5-6) were dominant in atmospheric environment, with greater long-range transport potential, whereas heavier groups (C12-13 and Cl7-10) were inclined toward deposition. It was clear that substantial amounts of SCCPs were released from the CP production plant, which contaminated the environment inside and outside of the plant. The daily occupational SCCP exposure of employees in the production hall (21.8 μg/day-kg) exceeded the tolerable daily intake (TDI, 10 μg/day-kg) given by Canadian Environmental Protection Act, suggesting that production employees were confronted with high health risk from SCCP exposure; while daily SCCP exposure of employees in office areas (0.57 μg/day-kg) and residents near the CP plant (1.22–25.5 × 10−2 μg/day-kg) were significantly lower, representing low health risk.

Development of a method for the determination of SCCPs (short-chain chlorinated paraffins) in bivalve mollusk using Soxtec device followed by gas chromatography-triple quadrupole tandem mass spectrometry

BackgroundOrganochlorinated compounds are major environmental concern due to their persistence, long-range transportability and bio-accumulation. Chlorinated paraffin (CP) mixtures, especially short-chain CPs (SCCPs), are found in environmental samples at very high levels. However, information about their levels is still insufficient, mainly in marine biota.MethodsThis study aimed to optimize and validate a method for the determination of SCCPs (short-chain chlorinated paraffins) in bivalve mollusk using a Soxtec extractor and Gas Chromatography coupled with Mass Spectrometry in tandem GC-QqQ-MS/MS (EI). A Plackett-Burman (2^7*3/16) type III resolution factorial design was used to optimize the extraction and purification procedures, sample amount, extractant volume, boiling and rinsing times as extraction variables and alumina, acid silica gel amounts and elution volume as purification variables.ResultsThe most influent factors were sample amount, rinsing time, extractant volume and acid silica gel amount. Further experiments were performed in order to attain the optimal values of these factors (4 g sample amount, 50 mL n-hexane-dichloromethane as extractant volume, 2 and 1.5 h boiling and rinsing times, 8 g alumina, 4 g acid silica gel (15%) and 50 mL n-hexane-dichloromethane as elution solvent). Validation of the optimized method presented recoveries higher than 90% with RSD below 10%, showing good accuracy and precision. The whole method limits of detection and quantification were 46.13 mg Kg- 1 and 153.75 mg Kg- 1, respectively. This method was successfully applied to the analysis of wild mussel samples coming from two Galician Rías. The found levels were very low compared to other marine systems, below parts per million.ConclusionsThe main advantages of the optimized method lie in the rapidity and the low amount of sorbents and volume of solvent used, as well as the selectivity and sensitivity of triple quadrupole MS/MS.