Medium-chain Chlorinated Paraffins Research Articles

Highly effective ashless and non-corrosive dimercaptobenzothiadiazole as multifunctional lubricant additives in naphthenic base oil.

The conventional medium chain chlorinated paraffin (MCCP) and zinc dialkyl dithiophosphate (ZDDP) additives have greatly enhanced the extreme pressure (EP) and anti-wear (AW) performance of the metalworking fluids. However, chlorine- and zinc-containing additives are restricted in use due to eco-toxicity issue. Herein, ashless and non-corrosive dimercaptobenzothiadiazole derivatives, namely bis-2,5-benzylsulfanyl-[1,3,4]thiadiazole (BBST) and bis-2,5-octylsulfanyl-[1,3,4]thiadiazole (BOST) consist of three sulfur atoms have been synthesized and evaluated. The performance of BBST shows a weld load (PD) of 3089 N and AW value of 5 mm2, which represents an improvement of 3.1 and 7.4 folds over naphthenic base oil (NBO). In addition, BBST also outperformed BOST, MCCP, and ZDDP in terms of its weld load and AW properties. Based on XPS analysis and molecular electrostatic potential maps (MEPS), BBST exhibits superior tribology performance due to the interaction between the sulfur (S), nitrogen (N), and π-electrons of the benzene ring with the metal surface. The formation of FeS, Fe2O3 and Fe⋯N coordinate bonds contributes to the creation of an excellent tribofilm.

Homologue-based Estimations of Short-Chain Chlorinated Paraffin Emissions and Concentrations in Japan

Short-chain chlorinated paraffins (SCCPs) are persistent organic pollutants. In Japan, SCCPs are widely detected in the environment although the production and use of SCCPs have been banned. It is essential to estimate the amount and sources of SCCPs to implement countermeasures for SCCP emission. In this study, we estimated the emission and environmental concentrations of SCCP homologues in Japan from 1950 to 2050. Initially, the material flow of total SCCPs was estimated considering the material recycling process. The emission from each process during the entire life cycle of products containing SCCPs was estimated for each homologue. Volatilization factors of long-term-use products were specifically estimated from release factors and surface area, weight, and SCCP concentration of products containing SCCPs. The environmental concentrations were then estimated using the environmental fate model. In the material flow and emission estimation, parameter uncertainties, such as emission factors and SCCP application distribution, were considered, assuming each parameter follows a uniform distribution. The results of emission estimation suggested a decreasing trend of SCCP emission in recent years and continuation of this trend in the future. However, some emissions from long-term-use products may persist. In the future, products that have a long lifetime with closed-loop recycling, such as polyvinyl chloride wire-coating materials, are expected to significantly contribute to atmospheric emission. Moreover, recycled products may contain SCCPs. Based on the estimated concentration, the estimated water and sediment concentrations were within the range of the observed concentrations. Conversely, we could reduce the gap between the estimated and observed atmospheric SCCP concentrations compared with those in previous studies that did not consider the volatilization factor for each SCCP-containing product and material recycling process. However, a difference between the estimated and observed concentrations suggests that some unconsidered emission sources may exist that emit SCCPs into the atmosphere, such as SCCPs as impurities in medium-chain chlorinated paraffins, imported products containing SCCPs, and atmospheric advection from other countries. Hence, it is essential to calculate emissions from sources other than products that intentionally contain SCCPs produced in the past.

Short- and medium-chain chlorinated paraffins in urban road dust of Shanghai, China: concentrations, source apportionment and human exposure assessment.

Chlorinated paraffins (CPs) are ubiquitous anthropogenic contaminants that have been found in various environmental media. The objective of this study was to determine concentrations, spatial distribution, possible sources and potential health risk of SCCPs and MCCPs in urban road dust collected from Shanghai, China. The concentrations ranged from 9.74 to 11,400ngg-1 for ΣSCCPs, 44.1 to 49,900ngg-1 for ΣMCCPs and 53.9 to 61,400ngg-1 for total CPs, respectively. MCCPs were the dominant component in all road dust, averagely accounting for 82.8% of total CPs. The concentrations of CPs in dust collected from traffic and commercial areas were significantly higher than those from campus, industrial, park and residential areas (p < 0.01), which could be attributed to tire wear in heavy traffic. All dust samples were divided into two groups by hierarchical cluster analysis for both SCCPs and MCCPs, and the most abundant homologue groups in most samples were C10Cl7-10 and C13Cl7-9 for SCCPs, and C14Cl7-9 and C15Cl8-9 for MCCPs. Correlation analysis showed that all carbon homologues in road dusts were highly correlated each other, suggesting SCCPs and MCCPs in dust maybe came from similar sources. Three sources for CPs in dust samples were apportioned by the PMF model; their relative contributions to the total CPs burden in dust were 25.6% for factor 1 (commercial CP mixture), 13.7% for factor 2 (long-distance transport) and 60.7% for factor 3 (commercial CP mixture). The median estimated daily intakes of total CPs via road dust were 1.78 × 10-5 for children and 3.0 × 10-6mgkg-1day-1 for adults, respectively. Quantitative risk assessment using non-cancer hazard index and total margin of exposure of total CPs indicated that total CPs at the present level in road dust pose no significant risk for both children and adults in Shanghai.

Congener profiles, air-soil exchange, and potential risks of short- and medium-chain chlorinated paraffins in demonstration zone of Yangtze River Delta

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) have been widely detected in soil environment. However, as a good matrix for trapping chlorinated paraffins (CPs) in the air, tree bark has been less studied for CP pollution, and limited information exists on the air-soil exchange of CPs. In this study, 48 CP congener groups were measured in the surface soils and tree barks from 36 points in the demonstration zone of the Yangtze River Delta (YRD). The concentrations of SCCPs and MCCPs in the soils were 3.97 × 10−2-1.13 and 0.237–13.8 μg/g dw, and their concentrations in the barks were 0.127–5.38 and 0.944–80.8 μg/g dw, respectively. Generally, the highest levels of CPs in both soils and barks were found in the Taipu River watershed, which were concentrated areas for the textile manufacturing activities. Congeners profile indicated that C10Cl5-8 and C14–15Cl5-7 were the major SCCPs and MCCPs. With respect to the air-soil exchange behaviors, 70.0% fugacity fractions (ffs) values were below 0.3, indicating the dominant deposition of CPs congeners, and log KOA values were inversely associated with the ffs. Significantly higher net depositions (3.06 ± 5.08 ng/(m2⋅h)) than emission fluxes (0.37 ± 1.18 ng/(m2⋅h)) were observed for MCCPs, while the trend was reversed for SCCPs. A preliminary risk assessment suggested that CPs pose a low ecological risk for the demonstration zone of the YRD and exerted low risks through dust ingestion and dermal contact.

Short and medium-chain chlorinated paraffins in indoor dust from a multistory residential building in Beijing, China: Vertical distribution and potential health risks

In this study, we conducted a preliminary investigation of the vertical distribution and potential health risks of short and medium-chain chlorinated paraffins (SCCPs and MCCPs) in indoor dust from a multistory residential building in Beijing, China. Forty-eight SCCP and MCCP congener groups in dust from different floors of the multistory residential building were determined by two-dimensional gas chromatography coupled with electron capture negative ionization mass spectrometry. The concentration ranges for SCCPs and MCCPs in the dust samples were 0.0239–207 μg/g and 0.135–2903 μg/g, respectively. MCCPs were the dominant group, on average accounting for 76.8 % of ∑CPs. Generally, the concentrations of both SCCPs and MCCPs greatly decreased as the floor level increased, which indicated that the CP contamination was attributed to exogenous atmospheric transport and deposition. C13Cl7–8 and C14Cl7–8 were the dominant SCCP and MCCP congener groups, possibly indicating the use of industrial CP-52 products was the main source of CPs. In the worst-case scenario using the maximum concentrations of CPs, the daily intake of SCCPs for toddlers was of the same order of magnitude as the reference dose. It should be noted that CPs exposure may be more serious when indoor decorations, furniture, and various plastic products are taken into consideration. Overall, more attention should be paid to CPs exposure and control measures in high-rise buildings.

Occurrence, spatial distribution, and risk assessment of short- and medium-chain chlorinated paraffins in sediment from black-odorous rivers across China

Chlorinated paraffins (CPs) were massively produced for varied industrial purposes, of which improper handling and consequent environmental release resulted in worldwide contamination. The present study investigated the occurrence and spatial distribution of short- and medium-chain chlorinated paraffins (SCCP/MCCPs) in 171 sediment samples from black-odorous urban rivers across China. Total SCCP and MCCP concentrations ranged from 8.3 to 9.4 × 104 (median: 1.1 × 103) ng/g dw, and from not-detected-value to 1.0 × 106 (median: 1.3 × 104) ng/g dw, respectively. No clear spatial distribution of SCCPs and MCCPs was observed since black-odorous urban rivers were polluted by point-sources of the SCCP/MCCPs. Significant positive correlations were identified between SCCP/MCCPs and total organic carbon, and between SCCP/MCCPs and other persistent organic matter, including polybrominated diethyl ethers, polychlorinated biphenyls, antibiotics, and plasticizers. The average ratios of MCCPs to SCCPs in most samples were divided into 11 and 16, implying the manufacturing and use of at least two types of CP technical mixtures in China. The composition of SCCP/MCCPs were similar to that in their commercial products. Ecological risk assessments by two approaches, including the Federal Environmental Quality Guidelines and Risk Quotient, both revealed that SCCP/MCCP in surface sediments confer an ecological risk. Environmental implicationSCCPs and MCCPs can be considered “hazardous materials” because of their massive production and their potential persistence, long-distance transfer, bioaccumulation potential, and toxicity. This research conducted a comprehensive study on SCCP/MCCP in black-odorous urban river sediments across China and revealed their environmental risk, which may improve understanding of SCCP/MCCP contamination characteristics.

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.

The impact of three related emission industries on regional atmospheric chlorinated paraffins pollution

Identifying the contributions of various chlorinated paraffins (CPs) sources in the environment plays an important practical role in the prevention and control of the CPs contamination. However, little is known about how main CP-related emission industries affect the regional atmospheric characteristics of CPs, including CP products industry, metal working industry, and polyvinyl chloride (PVC) industry. In this study, 60 passive air samples were collected from five typical cities in Henan Province, China, which had serious CP pollution and different structures of CP-related emission industry. Short chain CPs (SCCPs) and medium chain CPs (MCCPs) were detected in all samples in concentrations ranging of 2.6–7.7 × 102 and 2.1–4.3 × 102 ng m−3, respectively, which were higher than those in most reports. Moreover, Luoyang (LY) is different from other cities, showing a relatively severe MCCP contaminations. The CP pollution characteristics between different cities are obviously affected by the proportion of local CP-related industries. According to the results of cluster heatmaps, the local CP-related emission industrial structure had a greater impact on MCCPs pollution than SCCPs. Additionally, the contribution of metal working industry was beyond that of PVC production industry and CP products industry.

Influence of Sediment Dredging on the Distribution of Chlorinated Paraffin

To study the influence of dredged sediment transportation on the distribution of short-chain chlorinated paraffins (SCCPs, C10-13), medium-chain chlorinated paraffins (MCCPs, C13-17), and long-chain chlorinated paraffins (LCCPs, C18-28), 62 surficial sediment samples were collected from the Huangpu River and the Shanghai offshore areas, East China. A high-performance liquid chromatograph coupled with a quadrupole time-of-flight mass spectrometry system (HPLC-QTOF MS) was employed to measure CPs. The concentrations of CPs in sediment samples ranged from 8.76 to 1270.7 ng g−1 for SCCPs, from 22.03 to 1730.78 ng g−1 for MCCPs, and from undetected (ND) to 236.86 ng g−1 for LCCPs. The concentrations were lower than those that can be toxic to organisms. Furthermore, the influence of sediment dredging activity on the distribution of CPs was also investigated. The concentrations of CPs in sediment discarding areas were significantly higher than those in the surrounding areas, but this result is consistent with the concentrations in the Huangpu River sediments where CPs originated. Also, the SCCP congener group in the discarding area was similar to that in the Huangpu River. These findings indicated that CPs exhibited lower migration in the discarding area and had limited environmental impacts.

Initial dietary risk assessment of chlorinated paraffins in edible fungi in Chinese markets.

Dietary intake is one of the main pathways for residents to become exposed to chlorinated paraffins (CPs). In China, due to the popularization of nutritional and medicinal edible fungi, consumption has increased on a yearly basis. Edible fungi have a variety of active substances and are consumed daily by residents. However, there is limited information on the concentration and source of chlorinated paraffins in edible fungi. In this study, the concentrations of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in 105 edible fungi samples and 36 culture material samples were detected. The concentration range of SCCPs was 79.8ng/g dw to 3879.3ng/g dw, and the MCCPs was ND to 572.3ng/g dw. Spearman correlation analysis indicated that the sources of SCCPs and MCCPs in edible fungi were similar (r =0.57, p<0.01). The preponderant SCCPs and MCCPs congener group profiles were C10 Cl7-8 and C14 Cl6-8 . CPs were detected in culture materials, the concentration range of SCCPs was 320.2ng/g dw to 4326ng/g dw, and the MCCPs was 333.4ng/g dw to 4517.4ng/g dw. And the preponderant SCCPs and MCCPs homologues in culture materials were C11-12 Cl6 and C14 Cl6 . The linear discriminant analysis results indicated different contamination models of CPs between edible fungi and culture materials. The mean estimated daily intake values of SCCPs and MCCPs were 308.1ng/kg bw/d and 94.4ng/kg bw/d, respectively, indicating no potential health risk posed by CP exposure in edible fungi.

A fast gas chromatography coupled with electron capture negative ion mass spectrometry in selected ion monitoring mode screening method for short-chain and medium-chain chlorinated paraffins.

Chlorinated paraffins (CPs) are a group of anthropogenic pollutants that consist of complex mixtures of polychlorinated n-alkanes of different chain lengths (~C10 to C30 ). Persistence, bioaccumulation, toxicity, and long-range transport of short-chain chlorinated paraffins (SCCPs, C10 - to C13 -CPs) have prompted their classification as persistent organic pollutants (POPs) by the Stockholm Convention in 2017. Due to the varying chain lengths and chlorination degrees, quantification of SCCPs and medium-chain chlorinated paraffins (MCCPs, C14 - to C17 ) using gas chromatography coupled with electron capture negative ion mass spectrometry in selected ion monitoring mode (GC/ECNI-MS-SIM) is not only challenging but also very time consuming. In particular, up to eight GC runs per sample are required for the comprehensive GC/ECNI-MS-SIM quantification of SCCPs and MCCPs. These efforts are high especially if the samples do not contain CPs above the limit of detection (LOD), subsequently. We developed a semi-quantitative and sensitive method for the examination of SCCPs and MCCPs in one GC run. This GC/ECNI-MS-SIM screening method was based on the recording of Cl- (m/z 35 and 37), Cl2 - (m/z 70 and 72), and HCl2 - (m/z 71 and 73) isotope ions and evaluation of the ratios between them. Correctness of the results of the screening method was verified by analysis of edible oils with and without CPs, CP standards, as well as a technical CP mixture. Polychlorinated biphenyls (PCBs) and other polyhalogenated aromatic compounds, as well as brominated flame retardants, do not form all of the fragment ions analyzed by the screening method. After the screening, only CP-positive samples may need to be measured in detail. Measurement time will already be gained in the case of ~10% samples without CPs.

Evaluating the dynamic distribution process and potential exposure risk of chlorinated paraffins in indoor environments of Beijing, China

Chlorinated paraffins (CPs) are typical semi-volatile chemicals (SVOCs) that have been used in copious quantities in indoor material additives. SVOCs distribute dynamically between the gas phase and various condensate phases, especially organic films. Investigating the dynamic behaviors of existing CPs in indoor environments is necessary for understanding their potential risk to humans from indoor exposure. We investigate the distribution profiles of CPs in both gas phase and organic films in indoor environments of residential buildings in Beijing, China. The concentrations of CPs were in the range of 32.21–1447 ng/m3 in indoor air and in the range of 42.30–431.1 μg/m2 and in organic films. Cooking frequency was identified as a key factor that affected the distribution profiles of CPs. Furthermore, a film/gas partitioning model was constructed to explore the transportation and fate of CPs. Interestingly, a re-emission phenomenon from organic films was observed for chemical groups with lower log Koa components, and, importantly, their residue levels in indoor air were well predicted. The estimated exposure risk of CPs in indoor environment was obtained. For the first time, these results produced convincing evidence that the co-exposure risk of short-chain CPs (SCCPs), medium-chain CPs (MCCPs), and long-chain CPs (LCCPs) in indoor air could be further increased by film/gas distribution properties, which is relevant for performing risk assessments of exposure to these SVOCs in indoor environments.

Levels of Short- and Medium-Chain Chlorinated Paraffins in Edible Insects and Implications for Human Exposure.

This study reports on the occurrence and distribution of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively) in edible insects purchased from Asia and Europe. A total of 36 edible insect samples (n = 24 from Asia, n = 12 from Europe) authorized and prepared for human consumption were purchased and analyzed for SCCPs and MCCPs via gas chromatography and mass spectrometry. SCCPs were detected in 83% of all edible insect samples with an overall median ∑SCCP concentration of 8.7 ng/g dry weight (dw) and a range of <2.0 to 410 ng/g dw, while MCCPs were present in 92% of samples with a median ∑MCCP concentration of 51 ng/g dw and a range of <6.0 to 380 ng/g dw. Median ∑SCCP and ∑MCCP levels in edible insects purchased in Asia were approximately two- and four-times higher, respectively, than those from Europe, while the difference was statistically significant for ∑MCCPs (p < 0.001). Differences in homologue patterns were also observed between Asian and European samples to suggest diverse sources of CP contamination to insects which may include environmental accumulation, industrial processing equipment and food additives. Estimated daily intake of SCCPs and MCCPs via consumption of edible insects suggested that adverse health outcomes were very unlikely, but that continued monitoring of insect farming and processing practices are warranted.

Land-Ocean Exchange Mechanism of Chlorinated Paraffins and Polycyclic Aromatic Hydrocarbons with Diverse Sources in a Coastal Zone Boundary Area, North China: The Role of Regional Atmospheric Transmission.

The marine environment is regarded as a crucial "sink" of numerous land-origin pollutants. As typical boundary regions, the coastal and offshore areas are used to evaluate the dominating transfer process and land-ocean exchange mechanism of semivolatile organic compounds. In air samples collected from a coastal area in North China over a whole year, chlorinated paraffins (CPs), including short-chain CPs and medium-chain CPs, and prior control 16 polycyclic aromatic hydrocarbons (PAHs) were determined, with mean concentrations of 25.8 and 94.7 ng/m3, respectively. Results of different gas-particle partitioning models indicated that the steady-state hypothesis provides a better description of the possible land-ocean exchange molecular mechanism. The source-sink influences for CPs and PAHs were affected by the predominant atmospheric motion, which alternated between gaseous diffusion and particulate sedimentation in different seasons. Source apportionment results indicated that different transfer characteristics contributed to the source divergence of ambient CPs and PAHs within 12 nautical miles in the same area. Coal/biomass combustion and diesel/natural gas combustion were the main PAH sources in the coast site (43.1%) and sea site (35.3%), respectively. Similar industrial sources CP-52 and CP-42 were the main CP sources in the coast site (41.4%) and sea site (40.8%), respectively.

Short- and medium-chain chlorinated paraffins in polyvinyl chloride consumer goods available in the Japanese market

Chlorinated paraffins (CPs), including short-chain CPs (SCCPs) and medium-chain CPs (MCCPs), are hazardous chemical additives widely applied as plasticizers and flame retardants in polymers, mainly in polyvinyl chloride (PVC). In 2017, SCCPs were listed under the Stockholm Convention on Persistent Organic Pollutants (POPs). MCCPs were proposed for listing as POPs in 2021. SCCPs are also restricted under the Basel Convention, with two tentative low POP content (LPC) limits (100 and 10,000 mg kg−1) for SCCPs in waste. As a signatory Party of both conventions, Japan must ensure their implementation and manage SCCP wastes in environmentally sound ways. Therefore, we aimed to assess the occurrence of SCCPs and MCCPs in PVC consumer goods (n = 87) available in the Japanese market. CPs were detected in 48% of the samples. Regarding positive samples, children's products and toys (1.3–120,000 mg kg−1) were more impacted by SCCPs whereas electrical and electronic cables (1.2–59,000 mg kg−1) and house interior products (3.5–550 mg kg−1) were more impacted by MCCPs. Fourteen and four samples exceeded the LPC limit of 100 and 10,000 mg kg−1 for SCCPs, respectively. Most products were impacted by CP contents (<1 % w/w) considerably below those reported as intentional CP uses in PVC. However, 11 samples with total CP contents ranging from 1.3% to 15 % (w/w) might have been impacted by intentional CP use as secondary plasticizer in PVC. Most of the impacted consumer goods available in the Japanese market were manufactured overseas, highlighting that only restricting POPs nationally is not enough for thorough implementation of the Basel and Stockholm Conventions. Therefore, imported PVC consumer goods, PVC waste and PVC recycling streams need to be monitored as relevant potential sources of SCCPs worldwide, even where the national industry strictly follows the restriction of such chemicals.

Short- and medium-chain chlorinated paraffins in honey from China: Distribution, source analysis, and risk assessment

Chlorinated paraffins (CPs) are industrial chemicals produced in large quantities. Short-chain CPs (SCCPs) were classified as persistent organic pollutants under the Stockholm Convention in 2017. Medium-chain CPs (MCCPs) became candidate persistent organic pollutants in 2021. CPs are now ubiquitously found in the environment. Honey bees can be exposed to CPs during foraging, and this exposure subsequently results in the contamination of honey and other bee products along with colony food production and storage. Here, SCCP and MCCP concentrations in honey collected from Chinese apiaries in 2015 and 2021 were determined. Total CP concentrations in honey from 2021 to 2015 were comparable, but the ratio of MCCPs/SCCPs was higher in 2021 than in 2015. SCCP and MCCP congener group profiles in all honey samples were similar and dominated by C10–11Cl6–7 and C14Cl6–7, respectively. MCCP concentrations were also higher than SCCP concentrations in bees, pollen, and wax but not in bee bread, which were all collected in 2021. The order of average CP concentrations was determined as wax > bee > pollen > bee bread > honey. Poor relationships were found between SCCP concentrations in honey and other samples, but a relationship between MCCP concentrations in honey and other samples was observed. Migration tests of CPs in plastic bottles showed essentially no migration into honey during storage. The risks to humans from CPs in honey are low.

Dietary exposure and risk assessment of chlorinated paraffins in roots and rhizomes of traditional Chinese medicine herbs.

Traditional Chinese medicine (TCM) provides therapeutic and health care effects through dietary intake. Owing to the susceptibility of plants to contaminations, a risk assessment system is urgently needed to ensure the safe use of TCMs. In this study, the contamination levels and risks associated with the dietary intake of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were investigated in six kinds of frequently-used TCM herbs. The concentrations varied from 144.4 to 1527.8ng·g-1 dw for SCCPs and non-detect to 1214.1ng·g-1 dw for MCCPs, with mean values of 551.5 and 259.8ng·g-1 dw, respectively. A geographic distribution analysis indicated that the concentrations of CPs in TCMs were mainly associated with their levels of contamination in the ambient environment. Carbon atom-chlorine congener profiles of CPs were dominated by C10Cl7-8 and C14Cl7-8 congeners, accounting for 20.1% and 32.4% of the total SCCP and MCCP concentrations, respectively. Principal component analysis indicated that the TCM species might be the main factor influencing the accumulation of SCCPs congeners. Finally, a risk assessment reveals that the estimated daily intake and margin of exposure were far below levels that might pose a health risk, indicating an acceptable dietary intake of SCCPs and MCCPs in the studied TCMs. This is the first report of CPs in the TCM herbs and the obtained results are expected to aid in future evaluation of the quality of TCMs and ensuring diet and drug safety.

Exposure to short-, medium-, and long-chain chlorinated paraffins for infant via cow infant formula, goat infant formula and baby food

Dietary exposure is an important pathway for many pollutants from external exposure to human beings. In this study, we investigated the exposure to short-chain chlorinated paraffins (SCCPs), medium-chain chlorinated paraffins (MCCPs) and long-chain chlorinated paraffins (LCCPs), which are a class of industrial compounds that are of significant concern, in different infant foods (cow infant formula, goat infant formula and baby food are collectively called infant food in this study) in Chinese market. The concentrations of ∑SCCPs, ∑MCCPs and ∑LCCPs in infant foods were in the ranges of 6.22–273 ng/g, 13.1–2020 ng/g and 0.80–1280 ng/g, respectively. Especially, for the first time, we found that the proportion of ∑LCCPs (22.0%) in goat infant formula is almost equivalent to that of ∑SCCPs (25.0%), implying that LCCPs should also be further concerned since the related information is very scarce. There were differences between CP profiles among imported cow infant formula and Chinese cow infant formula due to the different sources of CPs to the infant formula. Imported infant foods were characterized by higher proportion of SCCPs, while Chinese infant foods were characterized by higher proportion on LCCPs. Margin of exposure results demonstrated that there was no significant health concern for the infant, but that large variation of CP concentrations and excessive feeding in practice may cause potential health threats to the infant. LCCPs were detected in all infant food samples, and to our knowledge, this is the first report of LCCPs in cow infant formula, goat infant formula and baby food. This study could provide important data of infant exposure to CPs, especially, LCCPs.

Occurrence, congener patterns, and potential ecological risk of chlorinated paraffins in sediments of Yangtze River Estuary and adjacent East China Sea.

Chlorinated paraffins (CPs) are high production volume chemicals with immense scientific research interest due to their wide distribution, persistence, toxicity, and bioaccumulation potential. In this study, 87 surface sediments were collected from the Yangtze River Estuary (YRE) and the adjacent East China Sea (ECS). We investigated the concentrations, spatial distribution, and composition profiles of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) using ultra-high-performance liquid chromatography coupled with Orbitrap Fusion Tribrid mass spectrometry. The sedimentary concentrations of SCCPs and MCCPs ranged from 2.85 to 94.7 ng·g-1 (median 13.7 ng·g-1) and 3.33 to 77.8 ng·g-1 (median 13.3 ng·g-1), respectively. Higher CP concentrations were found in YRE sediments. The values decreased away from the location, implying a direct influence of the Yangtze River. The SCCP concentrations were higher than those of MCCPs in most sediment samples. Overall, the predominant homologs were C13Cl5-7 and C14Cl6-8 for MCCPs and SCCPs, respectively. Overall, the sediment-dwelling organisms in the region are susceptible to low ecological risks.

Air–soil exchange of and risks posed by short- and medium-chain chlorinated paraffins: Case study in a contaminated area in China

Short-chain (SC) and medium-chain (MC) chlorinated paraffins (CPs) are found widely in the environment. Little research into air–soil exchange of SCCPs and MCCPs has been performed. In this study, CP concentrations, congener group profiles, and air–soil exchange in a typical contaminated area were investigated. A total of 10 soil samples and 10 air samples were collected from Zhoushan, an island in China. The samples were analyzed by two-dimensional gas chromatography electron capture negative ionization mass spectrometry. The SCCP and MCCP concentrations in the soil samples were 72–3842 and 117–8819 ng/g, respectively, and the SCCP and MCCP concentrations in the air samples were 57–208 and 1.8–25 ng/m3, respectively. The highest CP concentrations in both soil and air were found in samples from near shipyards, possibly because of CPs being emitted from metal cutting fluids and marine paints used at the shipyards. C14–15Cl7-9 were the dominant CP congener groups in the soil samples. C10Cl6–7 were the dominant CP congener groups in the air samples. Chlorinated decane and undecane and penta-, hexa-, and hepta-chlorinated CPs were enriched in the air relative to the soil. These congeners may have been released from the commercial CP-42 and CP-52. The fugacity fractions (ffs) of 48 homologs decreased as Koa increased. The ffs indicated that SCCPs and MCCPs dominated deposition. The net air–soil exchange fluxes of CPs were 201–769 ng/(m2·h). A preliminary risk assessment indicated that CPs pose low ecological risk except at sampling site S7 and do not pose significant health risks.