Characterization and health risks of short- and medium-chain chlorinated paraffins in the gas and size-fractionated particulate phases in ambient air.

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) have garnered significant attention because they have persistence and potential toxicity, and can undergo long-distance transport. Chlorinated paraffins (CPs) inhaled in the size-fractionated particulate phase and gas phase can carry different risks to human health due to their ability to accumulate in different regions of the respiratory tract and exhibit varying deposition efficiencies. In our study, large-volume ambient air samples in both the size-fractionated particulate phase (Dp < 1.0 µm, 1.0-2.5 µm, 2.5-10 µm, and Dp ≥ 10 µm) and gas phase were collected simultaneously in Beijing using an active sampler. The overall levels of SCCPs and MCCPs were relatively high, the ranges being 57-881 and 30-385 ng/m3, respectively. SCCPs tended to be partitioned in the gas phase (on average 75% of the ΣSCCP concentration), while MCCPs tended to be partitioned in the particulate phase (on average 62% of the ΣMCCP concentration). Significant correlations were discovered between the logarithm-transformed gas-particle partition coefficients (KP) and predicted subcooled vapor pressures (PL0) (p < 0.01 for SCCPs and MCCPs) and between the logarithm-transformed KP values and octanol-air partition coefficients (KOA) (p < 0.01 for SCCPs and MCCPs). Thus, the slopes indicated that organic matter absorption was the dominant process involved in gas-particle partitioning. We used the ICRP model to calculate deposition concentrations for particulate-associated CPs in head airways region (15.6-71.4 ng/m³), tracheobronchial region (0.8-4.8 ng/m³), and alveolar region (5.1-21.9 ng/m³), then combined these concentrations with the CP concentrations in the gas phase to calculate estimated daily intakes (EDIs) for inhalation. The EDIs for SCCPs and MCCPs through inhalation of ambient air for the all-ages group were 67.5-184.2 ng/kg/day and 19.7-53.7 ng/kg/day, respectively. The results indicated that SCCPs and MCCPs in ambient air do not currently pose strong risks to human health in the study area.

[Determination of short- and medium-chain chlorinated paraffins in different components of human blood using gas chromatography-electron capture negative ion-low resolution mass spectrometry].

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) have attracted significant attention because of their persistence, biotoxicity, bioaccumulation, and long-range migration. Given their worldwide detection in a variety of environmental matrices, concerns related to the high exposure risks of SCCPs and MCCPs to humans have grown. Thus, knowledge of the contamination patterns of SCCPs and MCCPs and their distribution characteristics in the vivo exposure of humans is of great importance. However, little information is available on the contamination of SCCPs and MCCPs in human blood/plasma/serum, mainly because of the difficulty of sample preparation and quantitative analysis. In this study, a new blood sample pretreatment method based on Percoll discontinuous density gradient centrifugation was developed to separate plasma, red blood cells, white blood cells, and platelets from human whole blood. A series of Percoll sodium chloride buffer solutions with mass concentrations of 1.095, 1.077, and 1.060 g/mL were placed in a centrifuge tube from top to bottom to establish discontinuous density gradients. The dosage for each density gradient was 1.5 mL. Human whole blood samples mixed with 0.85% sodium chloride aqueous solution were then added to the top layer of the Percoll sodium chloride solution. After centrifugation, the whole blood was separated into four components. The plasma was located at the top layer of the centrifuge tube, whereas the platelets, white blood cells, and red blood cells were retained at the junction of the various Percoll sodium chloride solutions. The sampling volume of human whole blood and incubation time were optimized, and results indicated that an excessively long incubation time could lead to hemolysis, resulting in a decrease in the recoveries of SCCPs and MCCPs. Therefore, a sampling volume of 1.5 mL and incubation time of 10 min at 4 ℃ were adopted. The cells of the blood components were further broken and extracted by ultrasonic pretreatment, followed by multilayer silica gel column chromatography for lipid removal. The use of 80 mL of n-hexane-dichloromethane (1∶1, v/v) and 50 mL of dichloromethane as the elution solvents (collected together) for the gel column separated the SCCPs and MCCPs from the lipid molecules in the blood samples. Gas chromatography-electron capture negative ion-low resolution mass spectrometry (GC-ECNI-LRMS) was used to determine the SCCPs and MCCPs. Quantification using the corrected total response factor with degrees of chlorination was achieved with linear corrections (R2=0.912 and 0.929 for the SCCPs and MCCPs, respectively). The method detection limits (MDLs) for the SCCPs and MCCPs were 1.57 and 8.29 ng/g wet weight (ww, n=7), respectively. The extraction internal standard recoveries were 67.0%-126.6% for the SCCPs and 69.5%-120.5% for the MCCPs. The developed method was applied to determine SCCPs and MCCPs in actual human whole blood samples. The contents of SCCPs and MCCPs were 10.81-65.23 and 31.82-105.65 ng/g (ww), respectively. Red blood cells exhibited the highest contents of CPs, followed by plasma, white blood cells, and platelets. The proportions of SCCPs and MCCPs in red blood cells and plasma were 70% and 66%, respectively. In all four components, the MCCP contents were higher than the SCCP contents, and the ratios of MCCPs to SCCPs ranged from 1.04 to 3.78. Similar congener patterns of SCCPs and MCCPs were found in the four components of human whole blood. C10-CPs and C14-CPs were predominantly observed in the SCCPs and MCCPs, respectively. In summary, a simple and efficient method was proposed to determine low concentrations of SCCPs and MCCPs in human blood with high sensitivity and selectivity. This method can meet requirements for the quantitative analysis of SCCPs and MCCPs in human blood components, thereby providing technical support for human health risk assessment.

Levels and diverse composition profiles of chlorinated paraffins in indoor dust: possible sources and potential human health related concerns.

Chlorinated paraffins (CPs), a group of mixtures with different carbon chain lengths and chlorine contents, are widely used as plasticizers and flame retardants in various indoor materials. CPs could be released from CP-containing materials into the ambient environment and then enter the human body via inhalation, dust ingestion and dermal absorption, resulting in potential effects on human health. In this study, we collected residential indoor dust in Wuhan, the largest city in central China, and focused on the co-occurrence and composition profiles of CPs as well as the resultant human risk via dust ingestion and dermal absorption. The results indicated that CPs with C9-40 were ubiquity in indoor dust with medium-chain CPs (MCCPs, C14-17) as the main components (6.70-495 µg g-1), followed by short-chain CPs (SCCPs, C10-13) (4.23-304 µg g-1) and long-chain (LCCPs, C≥18) CPs (3.68-331 µg g-1). Low levels (not detected-0.469 µg g-1) of very short-chain CPs (vSCCPs, C9) were also found in partial indoor dust. The dominant homolog groups were C9 and Cl6-7 groups for vSCCPs, C13 and Cl6-8 groups for SCCPs, C14 and Cl6-8 groups for MCCPs, and C18 and Cl8-9 groups for LCCPs. Based on the measured concentrations, vSCCPs, SCCPs, MCCPs, and LCCPs posed limited human health risks to local residents via dust ingestion and dermal absorption.

Gas/particle partitioning of short and medium chain chlorinated paraffins from a CP production plant using passive air sampler and occupational exposure assessment.

Short and medium chain chlorinated paraffins (SCCPs and MCCPs) attract increasing attentions due to their persistence, long-range transport capacity. Their gas/particle partitioning from the production emission source, the effects to the ambient environment and exposure for employees are worth revealing. Polyurethane foam based passive air samplers (PUF-PAS) was deployed to determine the environmental levels of SCCPs (63.4-719.7 ng/m3) and MCCPs (151.6-1009.2 ng/m3) in the gas-phase and particle-phase both in the outdoor air in a CP production plant and the indoor air in the workshops. Extremely high SCCPs were found in the chlorination workshop and outdoor samples nearby, attributing to the release during the production. In the workshops, dramatically higher SCCP concentrations were determined than outdoors. SCCPs and MCCPs predominated in the gas-phase with a proportion >80 %. C10-CPs and C14-CPs were dominated with a proportion higher than 20 % and 50 %, respectively. Significant correlations between log Kp' and log PL0 and log KOA were observed in the outdoor air in a CP production plant and the indoor air in the workshops, respectively. A multivariate mechanism based on adsorption by organic matters and influenced by absorption processes might determine the gas/particle partitioning of CPs in the production source area. Two scenarios of occupational exposure i.e. working in the workshops and working outdoors were considered. Higher occupational exposure via inhalation to MCCPs was found for employees than SCCPs in the workshops, which was estimated to be 137.1 ng/kg/day at a worst case. No obvious adverse effects were observed for occupational employees in this CP production plant.

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 79.8 ng/g dw to 3879.3 ng/g dw, and the MCCPs was ND to 572.3 ng/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 320.2 ng/g dw to 4326 ng/g dw, and the MCCPs was 333.4 ng/g dw to 4517.4 ng/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 308.1 ng/kg bw/d and 94.4 ng/kg bw/d, respectively, indicating no potential health risk posed by CP exposure in edible fungi.

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 1527.8 ng·g-1 dw for SCCPs and non-detect to 1214.1 ng·g-1 dw for MCCPs, with mean values of 551.5 and 259.8 ng·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.

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.

Structural Identification and Quantification of Chlorinated Paraffins in Fish Samples Using Comprehensive Two-Dimensional Gas Chromatography with Negative Chemical Ionization Quadrupole Time-of-Flight Mass Spectrometry and Comparison to a Direct Injection-Atmospheric Pressure Chemical Ionization-Orbitrap/Mass Spectrometry Method.

This study presents a comprehensive two-dimensional gas chromatography with negative chemical ionization quadrupole time-of-flight mass spectrometry (GC × GC-NCI-QTOF/MS) method, which allows for a precise chromatographic separation of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs). A new reversed-phase column setup was used, which allows for more accurate separation of MCCPs compared to known GC × GC methods. In a pilot study, 25 freshwater fish samples were analyzed with this method to characterize chlorinated paraffin (CP) compositions. The CP composition was similar in the samples, an observation that is important for the development of a suitable routine method. MCCP contamination was considerably higher than SCCP contamination, with concentrations of 1.3-410 ng/g of wet weight and 0.67-6.5 ng/g of wet weight, respectively. These results were compared to those obtained using a second method, direct injection-atmospheric pressure chemical ionization (APCI)-Orbitrap/mass spectrometry (MS). GC × GC separation was considered to be advantageous for accurate quantification of CP contamination.

[Levels and Risk Assessment of Short and Medium-Chain Chlorinated Paraffins in Soil from Paper Mill Area].

Short-chain chlorinated paraffins are persistent organic pollutants, and chlorinated paraffins were widely used as sizing agent in the paper industry. In order to investigate the levels and risk assessment of short-chain and medium-chain chlorinated paraffins in the paper mill plant, the surface soil and soil of different depths were collected.The concentrations, congener group profiles of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in soil were determined by two-dimensional gas chromatography coupled with electron capture-negative ion mass spectrometry. The SCCPs and MCCPs concentrations were 42-3853 ng·g-1 and 34-2091 ng·g-1. The chlorine contents were 59.9%-61.9% and 48.7%-52.8%. The concentrations of SCCPs and MCCPs were different in the soil collected in different sampling site. The concentration of SCCPs and MCCPs were relatively higher in soil of sewage treatment area and coating area. The CP levels in soil from the paper mill plant were at a high level compared with those in other regions. C10Cl6-7 and C14-15Cl5 were the main congener groups in most soil samples. The results of principal component analysis showed that the CP52 commercial products may be sources of SCCPs and MCCPs in the soil. The risk quotient (RQ) for SCCPs and MCCPs were assessed in soil of paper mill plant. The results showed that the RQ values for SCCPs in soil ranged from 0.01 to 0.73 which are the medium risk, and the RQ values for MCCPs in soil ranged from 0 to 0.07, which are the low risk. The human exposure values of children and adults are lower than TDI[10 µg·(kg·d)-1] in both cases. The health risks caused by non-dietary exposure under paper mill area are low.

Short and medium-chain chlorinated paraffins in serum from residents aged from 50 to 84 in Jinan, China: Occurrence, composition and association with hematologic parameters.

Human exposure to chlorinated paraffins (CPs) has been expected and assessed by external pathways considering their pervasive environmental occurrence. However, the deficiency of external exposure assessment in characterizing human burden is unavoidable. In addition, the associations between health outcomes and CP contents in human biospecimen are rarely assessed. In this study, we reported the occurrence and homologue profiles of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in serum samples from 145 residents aged from 50 to 84 in Jinan, Shandong Province of China using quadrupole time-of-flight high-resolution mass spectrometry coupled with atmospheric pressure chemical ionization source operated in negative ion mode (APCI-qTOF-HRMS). The associations between serum CP concentrations and hematologic parameters were further analyzed by linear regression. We identified high level of ∑SCCPs (median = 107 ng/g wet weight, ww; 13,800 ng/g lipid, lw), ∑MCCPs (median = 134 ng/g ww; 15,200 ng/g lw) and elevated ∑MCCPs/∑SCCPs (median = 1.12) in serum of the studied population. C13-CPs and C14-CPs were the most abundant SCCP and MCCP groups, respectively. While the predominant chlorine homologues among SCCPs and MCCPs were Cl7-8-CPs. ∑SCCPs, ∑MCCPs, ∑MCCPs/∑SCCPs and the homologue patterns presented no significant variance among age, sex and BMI groups. Further explorations suggested that perturbation of hematologic homeostasis could be induced by CP exposure in a sex-specific way, reflected by significant negative associations of serum SCCP and MCCP concentrations in lipid weight basis with sex-specific hematologic parameters. This study suffered from some limitations and should be interpreted with caution. However, the CP burdens of residents in China and the subsequent health risks must be underscored.

Short-, medium-, and long-chain chlorinated paraffins in South African indoor dust and cat hair.

Polychlorinated n-alkanes or chlorinated paraffins (CPs) contain a magnitude of structural isomers and are categorized as short-chain (SCCPs), medium-chain (MCCPs), and long-chain (LCCPs) CPs, according to the carbon chain lengths. In this study the Æ©SCCPs, Æ©MCCPs, and Æ©LCCP concentrations are reported for South African indoor dust and pet cat hair. The median concentrations of the Æ©CPs (C9-C37) ranged from 33 to 663 µg/g for freshly collected dust (FD), 36-488 µg/g for dust collected from household vacuum cleaner bags (VD), and 1.2-15 µg/g for cat hair (CH) samples. MCCPs were the dominant CP group, followed by SCCPs and LCCPs. The Æ©MCCP concentration ranged from 13 to 498 µg/g in dust and 0.6-6.5 µg/g in cat hair. SCCPs with shorter carbon chains and lower chlorine substitution were observed in cat hair. LCCPs with carbon chains > C20 were detected in dust and hair samples, possibly indicating the use of wax grade LCCP formulations. Non-traditional Kendrick mass defect plots were used to obtain information on the magnitude of CPs and provide evidence of possible interfering compounds. This is the first report on the occurrence of SCCPs, MCCPs, and LCCPs in the South African indoor environment.

Development a simple and rapid HPLC-ESI-Q-TOF/MS method for determination of short- and medium- chain chlorinated paraffins in human serum.

This study established a simple and rapid method for simultaneous determination of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in human serum by high performance liquid chromatography coupled with electron spray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF/MS). A simple pretreatment procedure of protein precipitation by acetonitrile coupled with liquid-liquid extraction by n-hexane was employed for extraction and purification. The purified samples were separated by a PFP chromatographic column. This method could effectively eliminate the matrix effect by lipids and other matrix substances in serum samples with less time and solvent consuming. 76 congener groups of SCCPs and MCCPs with C10-C17 and Cl5-Cl13 were quantified by their [M-H]- ions. Method detection limit (MDL) were 1.0-8.0 ng mL-1 for ∑SCCPs and ∑MCCPs. Recoveries were 98.4 ±â€¯4.42%, 98.8 ±â€¯3.96% and 90.7 ±â€¯2.79% for SCCPs and 93.1 ±â€¯6.67%, 108 ±â€¯1.21% and 90.8 ±â€¯3.78% for MCCPs at spiking concentrations of 20, 50 and 200 ng·mL-1, respectively. The relative standard deviations (RSDs) of intra- and inter-day variations were 1.41% and 9.84% for SCCPs, and 4.23% and 6.26% for MCCPs. The suitability of the developed method was demonstrated through the application to analysis of SCCPs and MCCPs in human serum samples.

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 (CnClm). 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 CnClm congener groups.

Destruction behavior of short- and medium-chain chlorinated paraffins in solid waste at a pilot-scale incinerator.

Incineration experiments with solid wastes containing approximately 3% (w/w) short-chain chlorinated paraffins (SCCPs) that have recently been listed as persistent organic pollutants (POPs) and medium-chain chlorinated paraffins (MCCPs) were conducted using a pilot-scale incinerator to investigate the efficiency of their destruction as well as the unintentional formation of POPs and their destruction behaviors during controlled incineration. A series of experiments demonstrated that SCCPs and MCCPs in solid wastes were progressively destroyed and removed during rotary kiln combustion and downstream flue gas treatments. Destruction efficiencies of SCCPs and MCCPs exceeding 99.9999% were confirmed. SCCPs in bottom and fly ash samples were present at levels below their quantification limits (0.021 and 0.31 mg/kg), and MCCPs in the bottom and fly ash samples were likewise present at concentrations below their quantification limits (0.034 and 0.50 mg/kg). Total concentrations of toxicity equivalency quantities (TEQs) for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in emission gas samples collected at the bag filter exit and final exit were 0.083-0.30 and 8.7 × 10-7 to 1.3 × 10-4 ng-TEQ/m3N, respectively, and those in bottom and fly ash samples were 0.12-0.47 and 9.0 × 10-3 to 0.14 ng-TEQ/g, respectively. The results obtained in this study suggest that controlled incineration of solid wastes under the current regulations for incinerators in Japan and the countries with regulations and monitoring to minimize emissions of PCDDs/DFs and dl-PCBs is one of the best available technologies for the environmentally sound management of wastes containing SCCPs and MCCPs.

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.

Short- and medium-chain chlorinated paraffins in the Henan section of the Yellow River: Occurrences, fates, and fluxes.

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in sediment and suspended particulate matter (SPM) from the middle and lower reaches of the Yellow River in the three seasons to elucidate their environmental behavior. The mean concentrations of ∑SCCPs and ∑MCCPs were 262 and 97.1 ng g-1 dw (dry weight) in sediment and 17,055 and 2573 ng g-1 dw in SPM, respectively, and higher SCCP levels did not clearly reflect a shift to more MCCPs in this section of the Yellow River. The predominant homologue groups were C10-CP and C11-CP for SCCPs and C14-CP for MCCPs. The CPs possibly mainly derived from the use of CP commercial mixtures, mainly included CP-42 and CP-52. The spatial distributions and principal component analysis indicated that industrial inputs, dams, and topography played important roles in influencing the environmental behavior of CPs in both sediment and SPM. In addition, decreasing fluxes of CPs were observed in SPM from Tongguan to Aishan stations, particularly in reservoirs, which implies that CPs may have accumulated in the Henan section of the Yellow River.

Ecotoxicity assessment of short- and medium-chain chlorinated paraffins used in polyvinyl-chloride products for construction industry.

Short chain chlorinated paraffins (SCCPs) have been commonly used as plasticizers and flame retardants in polyvinyl-chloride (PVC) products for the construction industry. During the last few years the production of SCCPs has been banned or reduced in Europe, Japan, USA, and Canada due to their toxic and bioaccumulative effects but they have been still produced and used under less controlled conditions worldwide. Middle chain chlorinated paraffins (MCCPs) were suggested as a suitable alternative to SCCPs for PVC production instead. In this paper, the ecotoxicity of SCCPs and MCCPs is studied using the methods of potentially affected fraction of species (PAF) and the most sensitive species (MSS). Characterization factors (CFs) are estimated for SCCPs by the PAF method (for MCCPs suitable ecotoxicological indexes are not available) and for MCCPs by the MSS method (for SCCPs PEC values are negligible). Results of the present study indicate that from an ecotoxicological point of view, MCCPs may present similar ecological risks as SCCPs. Therefore, it is recommended both SCCPs and MCCPs not to be used worldwide in PVC products for the construction industry. The most suitable alternative for SCCPs seems to be inorganic compounds but their environmental impacts have not been sufficiently excluded yet.

Short- and medium-chain chlorinated paraffins in aquatic foods from 18 Chinese provinces: Occurrence, spatial distributions, and risk assessment.

Short-chain chlorinated paraffins (SCCPs) are classed as persistent organic pollutants and were included in the Stockholm Convention in May 2017. Large amounts of chlorinated paraffins (CPs) are produced in China than in any other countries. CPs can be released into the environment while being produced and used, and can bioaccumulate in aquatic biota and be ingested by humans. Dietary intake is the main route through which humans are exposed to CPs. It has previously been found that persistent organic pollutant concentrations are usually higher in aquatic foods than in other foods. The risk of human exposure to SCCPs in aquatic foods should therefore be of concerns. However, SCCP concentrations in aquatic foods have not been systematically studied. A total of 1620 aquatic food samples were collected, and 18 pooled samples were analyzed by two-dimensional gas chromatography coupled with electron-capture negative-ionization time-of-flight mass spectrometry. The mean SCCP and MCCP concentrations were 1472 and 80.5ng/gwet weight, respectively. The dominant SCCP and MCCP congener groups were C10Cl6-7 and C14Cl7-8, respectively. The concentrations were much higher than those have been found in aquatic foods in other countries. The CP concentrations in the samples consumed by local people from eastern and southern China were higher than the concentrations in samples from central and western China. Risk assessment results indicated that SCCPs and MCCPs in aquatic foods do not pose significant risks to residents of China.

Concentrations and congener profiles of chlorinated paraffins in domestic polymeric products in China.

Chlorinated paraffins (CPs) are widely used in domestic polymeric products as plasticizers and fire retardants. In this study, concentrations and congener profiles of short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) were investigated in domestic polymeric products, including plastics, rubber and food packaging in China. The average concentrations of SCCPs in polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE) and food packaging were 234, 3968, 150 and 188 ng/g, respectively and the corresponding average concentrations of MCCPs in these samples were 37.4, 2537, 208 and 644 ng/g, respectively. The concentrations of CPs in rubber and polyvinylchloride (PVC) were significantly higher than in other matrices. The highest concentrations of SCCPs and MCCPs were found in a PVC cable sheath with 191 mg/g and 145 mg/g, respectively. Congener group profiles analysis indicated C11- and C13-congener groups were predominant in carbon homologues of SCCPs, and C14-congener groups were predominant in MCCPs. High levels of SCCPs and MCCPs in domestic polymeric products implied that they might be a significant source to the environment and human exposure.

Spatial and temporal trends of short- and medium-chain chlorinated paraffins in sediments off the urbanized coastal zones in China and Japan: A comparison study.

To examine the impacts of urbanization and industrialization on the coastal environment, and assess the effectiveness of control measures on the contamination by chlorinated paraffins (CPs) in East Asia, surface and core sediments were sampled from the urbanized coastal zones in China and Japan (i.e., Pearl River Delta (PRD), Hong Kong waters and Tokyo Bay) and analyzed for short-chain (SCCPs) and medium-chain CPs (MCCPs). Much higher concentrations of CPs were found in the industrialized PRD than in adjacent Hong Kong waters. Significant correlation between CP concentration and population density in the coastal district of Hong Kong was observed (r2 = 0.72 for SCCPs and 0.55 for MCCPs, p < 0.05), highlighting the effect of urbanization. By contrast, a relatively lower pollution level of CPs was detected in Tokyo Bay. More long-chain groups within SCCPs in the PRD than in Hong Kong waters and Tokyo Bay implied the effect of industrialization. Comparison of temporal trends between Hong Kong outer harbor with Tokyo Bay shows the striking difference in historical deposition of CPs under different regulatory situations in China and Japan. For the first time, the declining CP concentrations in Tokyo Bay, Japan, attest to the effectiveness of emissions controls.