Search

The presence of polychlorinated biphenyls (PCBs) in feed materials has caused great public concern because PCBs can accumulate in farmed animals, be transferred farm-to-fork and, ultimately, have a detrimental impact on human health. Recently, the occurrence of PCBs in marine environments has garnered scientific attention due to their high levels and potential reproductive threats to marine apex predators. Fishmeal is marine-origin feed material and is susceptible to PCB contamination from the aquatic trophic chain. The present study collected 102 fishmeal samples during 2012–2017 from major global fishmeal production areas (United States, Europe, China, South America and Southeast Asia). The levels of PCBs (26 congeners) were between 0.4 and 19.9 ng g−1 dw (mean: 1.94 ng g−1 dw), with a 75.3% contribution from indicator PCBs on a weight basis. Together with PCDD/Fs, 4.9% of fishmeal exceeded the maximum levels set by the European Commission for dioxin-like compounds (4.0 pg WHO-TEQ/g). The highest PCB levels were found in fishmeal from the U.S. (6.85 ng g−1 dw), which was nearly five times higher than the other four sampling areas. No clear time trends were found for PCBs in fishmeal during the sampling period. Predicted PCB concentrations in farmed fish via fishmeal consumption were between 1.24 and 2.76 ng g−1 dw, which was comparable to PCBs in market fish. When compared to other emerging POPs in the same batches of fishmeal, PCBs were still found to be an alarming class of POPs. Some PCB and PBDE congeners might have similar sources and environmental behaviors. Image 1 • The occurrence and profile of PCBs were identified in global fishmeal. • Fishmeal from the U.S. presented the highest PCB levels of five studied regions. • PCBs are still significant POPs despite having leveled off in marine environments. [ABSTRACT FROM AUTHOR]

Highlights • The formation of PCNs during the heating of sucralose was investigated. • Factors affecting PCN formation and distribution were determined. • Naphthalene chlorination might be an important pathway for PCN formation. [ABSTRACT FROM AUTHOR]

Abstract Concentrations and patterns of 75 PCN congeners in feed raw materials of animal and plant origin were investigated. Six types of feed raw materials of animal origin and three types of feed raw materials of plant origin from China were collected in 2016. The total concentrations of PCNs in the collected materials ranged from 147 to 1009 ng kg-1, with the highest occurring in fish meal. The mean PCNs concentration in feed raw materials of animal origin (551 ng kg-1) was higher than in those of plant origin (294 ng kg-1). Additionally, lower chlorinated PCNs were the main homologues in raw feed materials, while Di-CNs were the predominant homologues in all samples (mean: 53%), followed by tri-CNs (mean: 28%). The most abundant congeners were CN5/7 and 24/14. Additionally, the toxicity equivalencies (TEQs) of PCNs in the feed raw materials ranged from 0.010 to 0.046 ng TEQ kg-1, with the highest TEQ concentrations of PCNs detected in gluten meal. Together, CN5/7, 66/67, 65/70, and 73 contributed approximately 64% of the total PCN TEQs in raw feed materials. Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in the feed raw materials were detected to compare the TEQ distribution of those dioxin-like compounds. The mass concentrations of PCNs were 1–3 orders of magnitude higher than those of PCDD, PCDFs and PCBs, while the TEQ concentrations of PCNs contributed 2.0%–6.5% of the total TEQs of PCNs, PCDDs, PCDFs and PCBs in the feed raw materials. Highlights • Concentrations of 75 PCN congeners were determined in feed raw materials. • Relatively high PCN concentrations were found in fish meal. • PCN TEQs were lower than those of PCDDs, PCDFs or PCBs in the same samples. • Potential sources for PCNs in feed raw materials were discussed. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH) and methoxylated (MeO) structural analogues have been found widely distributed in aquatic ecosystems, and may exhibit potential adverse effects to humans due to their bioaccumulative behavior through food chain. Fishmeal is an important animal feed applied around the world and is generally of marine origin. However, the levels and sources of PBDEs in fishmeal have not been thoroughly evaluated and their structural analogues have not been reported to date. The present study collected ninety-two fishmeal samples from world main fishmeal producing area to determine 27 PBDEs, 10 MeO-PBDEs and 11 OH-PBDEs. The concentrations of Σ 27 PBDEs, Σ 10 MeO-PBDEs and Σ 11 OH-PBDEs were in the ranges of 0.1–1498 (mean: 75.8), 1.14–881 (37.4) and 1.00–47.5 (8.17) ng/g lipid, respectively. PBDEs were found primarily correlated with the historically commercial production, meaning higher production of certain commercial product in a country, higher corresponding PBDE congeners in local fishmeal. A market shift from penta- and octa-formulations toward deca-formulation was observed. BDE209 was identified as a major congener in fishmeal. Both the MeO-PBDEs and the OH-PBDEs were influenced by fishmeal producing areas (p < 0.001). High MeO-PBDEs were identified in the Southeast Asian fishmeal, which might be due to the suitable environmental conditions for the generation of bromoperoxidase-contained algae in local area. The ratio of two major MeO-PBDE congeners, 6-MeO-BDE47/2′-MeO-BDE68, were generally >1 in the northern hemisphere and <1 in the southern hemisphere in the present study, which was consistent with the results obtained from previous published papers. Both MeO-PBDEs and OH-PBDEs were in accordance with the specialties of naturally produced halogenated compounds. [ABSTRACT FROM AUTHOR]

Polychlorinated naphthalenes (PCNs) are toxic and can accumulate through the food chain. PCNs have been detected in different categories of foods. Intake of animal-derived foods is an important pathway for human exposure to PCNs. However, information on PCNs in meat from farmed animals is scarce. In this study, PCNs were assessed in beef sourced from local markets in Beijing and six provinces in China. The mean PCN concentrations in beef samples from the seven regions varied from 41.2 to 88.7 pg/g wet weight (ww). The homologue profiles of PCNs in the specimens were similar, with tri- and di-CNs being dominant. The mean concentration of PCNs in the flank (74.7 pg/g ww) was higher than that in the round (58.2 pg/g ww) or shank (53.6 pg/g ww), likely because the former contained a higher proportion of lipids than the latter. Significantly different PCN distributions in beef and dairy cow milk were identified using machine learning. The toxic equivalencies (TEQs) of PCNs in all beef samples ranged from 0.0003 to 0.022 pg TEQ/g ww. PCNs contributed to approximately 4.6% of the total TEQ values of polychlorinated dibenzo- p -dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, and PCNs in the beef. Health risks related to the intake of PCNs through beef consumption by the average person living in China were minimal. [Display omitted] • PCN homologue profiles in beef from different regions of China were similar. • PCN concentrations in flank were higher than in round and shank. • Variations in lower chlorinated PCN congeners between beef and milk were identified. • PCN contributions to total TEQs were lower than those of other dioxin-like compounds. • The risks of exposure to PCNs through beef consumption in China are low. [ABSTRACT FROM AUTHOR]

Polychlorinated naphthalenes (PCNs) were listed as persistent organic pollutants in the Stockholm Convention in 2015. Despite numerous studies on PCNs, little is known about their occurrence in atmospheric particulate matter of different sizes. In this study, 49 PCN congeners were investigated for their concentrations and size-specific distributions in an urban atmosphere, and preliminary exposure assessments were conducted. Ambient air samples were collected using a high-volume cascade impactor for division into a gas fraction and four particle size fractions. Samples were collected from October 2013 to June 2014 at an urban site in Beijing, China. The concentration range for PCNs in the atmosphere (gas + particle fractions) was 6.77–25.90 pg/m 3 (average 16.28 pg/m 3 ). The particle-bound concentration range was 0.17–2.78 pg/m 3 (average 1.73 pg/m 3 ). Therefore, PCNs were mainly found in the gas phase. The concentrations of PCNs in a fraction increased as the particle size decreased (d ae > 10 μm, 10 μm ≥ d ae > 2.5 μm, 2.5 μm ≥ d ae > 1.0 μm and d ae ≤ 1.0 μm). Consequently, PCNs were ubiquitous in inhalable fine particles, and the ΣPCNs associated with PM 1.0 and PM 2.5 reached 68.4% and 84.3%, respectively. Tetra-CNs and penta-CNs (the lower chlorinated homologues) predominated in the atmosphere. The homologue profiles in different size particles were almost similar, but the particulate profiles were different from those in the gas phase. Among the individual PCNs identified, CN38/40, CN52/60 and CN75 were the dominant compounds in the atmosphere. CN66/67 and CN73 collectively accounted for most of the total dioxin-like TEQ concentrations of the PCNs. Exposure to toxic compounds, such as PCNs present in PM 1.0 or PM 2.5 , may affect human health. This work presents the first data on size-specific distributions of PCNs in the atmosphere. [ABSTRACT FROM AUTHOR]

Polychlorinated naphthalenes (PCNs) are highly toxic and persistent organic pollutants that can cause adverse effects in the environment and on human health. PCNs have been detected in remote areas because of their long-range transportation. Bees and bee products are commonly used as biomonitors for various pollutants in the environment. However, information on PCNs in apiaries is scarce. The aim of this study was to evaluate the occurrences of PCNs in bees and bee products from apiaries located in different geographical regions of China, and to identify potential pollution sources and assess exposure risks to humans. Our results showed that the average Σ 75 PCNs concentrations in bees, pollen, and wax were 74.1, 96.3, and 141 pg/g dry weight, respectively. The homologue and congener profiles of PCNs in bees, pollen, and wax were similar, and di- and tri-chlorinated naphthalenes (>60%) were the predominant homologues. The concentrations and distributions of PCNs in bees, pollen, and wax varied among different geographical regions, but their occurrences were correlated with PCN metallurgical sources in China. The health risks of PCNs in pollen were evaluated, and both carcinogenic and non-carcinogenic risks of PCNs exposure to humans through the diet were low. [Display omitted] • Polychlorinated naphthalene contents in bees, pollen and wax were region-dependent. • Less-chlorinated homologues were predominant in bees, pollen, and wax. • PCNs in bees, pollen, and wax were correlated with metallurgical sources in China. • The exposure risk of PCNs in bee pollen to humans was low. [ABSTRACT FROM AUTHOR]

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 C 10 – 11 Cl 6–7 and C 14 Cl 6–7 , 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. [Display omitted] • Higher MCCP/SCCP concentration ratio was found in honey from 2021 than from 2015. • CP concentrations were higher in wax, bees, and pollen than in bee bread and honey. • MCCPs in bees, bee bread, honey, pollen and wax were positively related with each other. • CP migration from plastic packaging to honey during storage was not observed. • Chlorinated paraffins in honey pose low risk to humans. [ABSTRACT FROM AUTHOR]

• A total of 75 PCN congeners in raw cow milk from China were determined. • PCN concentrations in cow milk could be influenced by PCN emission sources. • PCNs in cow milk were dominated by lower chlorinated congeners. • Silage acted as an important carrier for the migration of PCNs into cow milk. • Chinese exposure risk to PCNs through the intake of cow milk is not significant. The potential contamination of food items with polychlorinated naphthalenes (PCNs) has attracted increasing attention because of their toxicity, persistence and bioaccumulative characteristics. Humans are exposed to PCNs primarily through consuming animal-derived foodstuffs. However, the pathways by which PCNs can enter the food supplying chain are poorly understood. In this study, Σ 75 PCNs were determined in raw cow milk (n = 82) collected from three different regions that varied in the intensity of PCNs emission sources in North China, using high-resolution gas chromatography/high-resolution mass spectrometry method. Higher PCN concentrations (214–2050 pg/g lw) were found in raw cow milk from dairy cow farms located in the region with relatively higher intensity of emission sources. Less chlorinated congeners were dominant in all raw cow milk samples. PCNs in cow milk might result from industrial fly ash emissions that contaminate animal feed through atmospheric deposition. Risks posed to humans through consuming PCNs in cow milk were low. [ABSTRACT FROM AUTHOR]

Abstract: Sucralose, an artificial sweetener, is being used in increasingly large amounts in foodstuffs and beverages worldwide. Information pertaining to its ability to participate in chlorination reactions during cooking and generate toxic compounds, however, is scarce. In this study, the formation and distribution of polychlorinated naphthalenes (PCNs), which are a group of highly toxic polychlorinated aromatic compounds, in oil heated in the presence of sucralose was investigated. The concentrations of the PCNs present in the cooking oils and oil fumes generated during the heating process were determined by isotope dilution according to a HRGC/HRMS method. The results suggested that the heating of cooking oil in the presence of sucralose promoted the formation of toxic PCNs. Although PCNs were detected in the oil fumes, no PCNs were found in the heated oils. The total concentrations of the PCNs found in peanut and olive oil fumes were 490 and 240 pg g−1, respectively. The degree of chlorination for the PCNs was calculated to be 5.3 for both the peanut and olive oil fumes. To quantify the newly produced PCNs, sucralose used in the experiments were about 2 or 3 orders of magnitude higher than in reality. PCNs were not detected with real proportions under the current experimental conditions. [Copyright &y& Elsevier]

Abstract: The formation and distribution of dioxin-like polychlorinated biphenyls (dl-PCBs) during cooking was investigated. Concentrations of dl-PCBs in liquid residues, cooked beef, and oil fumes generated during heating were determined by isotope dilution HRGC/HRMS. Although the levels of dl-PCBs in well-done beef were lower compared with those of raw beef, relatively high concentrations of dl-PCBs were detected in the oil fumes produced during heating. This suggests that dl-PCBs in raw beef may have volatilized into the oil fumes during the cooking process. Sucralose and chloropropanols contained in raw materials may have resulted in increased dl-PCB concentrations and the level of toxic equivalents (TEQ) in the oil fumes produced under high temperature during cooking. Concentrations of dl-PCBs did not vary greatly in cooked beef, except when higher levels of chloropropanols were presented in the uncooked raw materials. Results indicate that sucralose and chloropropanols may promote the formation of dl-PCBs during the cooking process. The newly produced dl-PCBs from raw beef cooking were mainly present in oil fumes, which gave rise to high levels of TEQ in oil fumes. [Copyright &y& Elsevier]

Increasing concerns over bisphenol A (BPA) as an endocrine disrupting chemical (EDC) and its adverse effects on both humans and animals have led to the substitution by structural analogs, such as bisphenol F (BPF), in many application areas. Information regarding to the carry-over of this emerging chemical in farm animals is essential for legislation and risk assessment purposes. In this study, a large-scale number of animal experiments were designed to investigate the transfer of BPF from feed to eggs. One control and three experimental groups of laying hens (72 hens per group) were fed with basal diets and BPF-contaminated feed at concentration levels of 0.1, 0.5 and 2.5 mg kg−1, respectively, for two weeks. The hens were then fed with BPF-free diets for a further four weeks. Eggs were collected daily, and separated into egg yolk and white for BPF analysis. The effects of different levels of BPF exposure on laying performance followed a non-monotonic dose-response curve, since low level BPF (0.1 mg kg−1) exposure did increase the laying rate, mean egg weight and daily feed intake, while high level BPF (2.5 mg kg−1) exposure showed a decreasing trend. BPF residues were detected in both egg yolks and whole eggs after two days of administration, and plateau phase was achieved within 9–18 days. There are clear linear dose-response relationships between the plateau BPF concentrations in feed and eggs. The residue of BPF was found mainly in egg yolks with conjugated form and depleted slowly (still detected 21 days after feeding the BPF-free diet of the high level group). Mean carry-over rate of 0.59% BPF from feed to eggs was obtained. Compared with the carry-over rates of PCBs and dioxins, BPF showed a relatively minor trend of bioaccumulation in eggs. To the best of our knowledge, this is the first report on the deposition, depletion, and bioaccumulation study of bisphenols in farm animals. The quantity of data can therefore be helpful in the frame of risk assessment, especially for a comprehensive estimation of consumer exposure to the residues of bisphenols. Image 1 • Effects of bisphenol F (BPF) exposure on egg production followed non-monotonic dose-response curves. • Residues of BPF were mainly in egg yolks with conjugated form and depleted slowly. • Mean carry-over rate of 0.59% BPF from feed to eggs was calculated. • Suggestively, BPF might not bioaccumulate in eggs relative to polychlorinated biphenyls (PCBs) and dioxins. [ABSTRACT FROM AUTHOR]

• High SCCP and MCCP concentrations were found in raw cow milk from industrial areas. • SCCP concentrations in raw milk and silage were higher than MCCP concentrations. • Animal feed might be an important source of dairy cow exposure to SCCPs and MCCPs. • Bioconcentration factors for SCCPs and MCCPs in cow milk were calculated. • The exposure of Chinese residents to SCCPs and MCCPs via cow milk is minimal. Chlorinated paraffins (CPs) are industrial chemicals that are produced in large quantities and used globally. Human exposure to CPs is primarily through dietary intake, especially from animal-derived food products. Even so, there is little information regarding CP concentrations in dairy products. In this study, raw samples of cow milk were collected from various regions in China within the Neimenggu (n = 10), Hebei (n = 9), Shandong (n = 10), Henan (n = 10) and Hubei (n = 9) provinces. The mean concentrations of short chain CPs (SCCPs) and medium chain CPs (MCCPs) in the milk samples from industrial areas (1670 and 190 ng/g lipid, respectively) were higher than those from non-industrial areas (490 and 72 ng/g lipid, respectively). In most samples, C 10 H 16 Cl 6 and C 14 H 23 Cl 7 were the primary SCCP and MCCP congener groups, respectively. The mean concentrations of SCCPs and MCCPs in dairy cow feed (silage) were determined to be 750 and 36 ng/g dry weight, respectively. The SCCP and MCCP congener group patterns in the milk were similar to those in the silage, indicating that animal feed intake might be an important pathway for the exposure of dairy cows to CPs. Thus, the ingestion of CPs by humans through dairy products should not be neglected and the contamination of animal feed by CPs should be considered. [ABSTRACT FROM AUTHOR]

Full waveform inversion is a nonlinear fitting technique that requires regularization methods to alleviate ill-posedness. Based on the newly introduced Graph-Laplacian regularization, which offers outstanding manifold learning, we propose a novel regularization method for FWI that can combine the graph Laplacian matrix with a sparse representation in a learning-based dictionaries. Besides employing an adaptive sparsity prior, the graph Laplacian matrix incorporates the nonlocal self-similarity prior into the FWI process, and consequently improve the stability of the inversion process and produce more accurate inversion results. The Alternating Direction Method of Multipliers (ADMM) is applied to solve the problem numerically. A series of experiments are performed on the Marmousi model and the BG Compass model. The experimental results verify the effectiveness of the proposed FWI method in both quantitative analysis and visual perception. • The graph Laplacian regularizer combines with an adapted dictionary. • Graph Laplacian matrix incorporates the self-similarity prior into the FWI process. • The ADMM framework improves the FWI quality. [ABSTRACT FROM AUTHOR]

Animal-derived food plays an important role in human exposure to bisphenol compounds (BPs), potentially as a result of the presence of BPs in animal feed. Even so, there have been few studies regarding the source of BPs in animal feed. The objective of the present study was to assess both the occurrence of BPs in animal feed packaging and the migration of BPs from feed packaging into animal feed. Thirteen BPs were monitored in 30 used animal feed plastic packaging samples previously employed for different animal feedstuffs and made of polypropylene (PP) or polyethylene (PE). Six and two BPs were found in PP-based woven bags and PE-based films, respectively. Bisphenol A (BPA) was the predominant analogue with a wide range of concentrations in both the PP- and PE-based packaging. A migration experiment was performed and provided the first-ever confirmation that BPA is able to migrate from plastic packaging into solid feed. Both contact time and the initial BP concentration affected the extent of migration. These results expand our knowledge regarding the origin of BPs in the food chain and suggest that further study of the bioaccumulation of BPs in animals is warranted. Image 1 • The potential for BPs to enter animal feed from plastic packaging was assessed. • Several BPs were found in animal feed plastic packaging and BPA was predominant. • BPA was found to migrate from plastic packaging into solid animal feed. • BPA levels in packaging and contact time were the main factors determining migration. [ABSTRACT FROM AUTHOR]

There is very little information on the levels and particle size distributions of lower chlorinated dibenzo- p -dioxins and dibenzofurans (mono- to tri-CDD/Fs, ΣCl 1–3 DD/Fs) in the atmosphere, while a number of studies have examined tetra- to octa-chlorinated homologues (ΣCl 4–8 DD/Fs). In this study, we measured the concentration and particle size distribution of ΣCl 1–3 DD/Fs in ambient air in suburban Beijing and compared them with that of ΣCl 4–8 DD/Fs for the first time. The mean concentration of ΣCl 1–3 DD/Fs was 54.63 pg m −3 , which is about 5.4 times that of ΣCl 4–8 DD/Fs. The ΣCl 1–3 DD/Fs accounted for 85% of ΣCl 1–8 DD/Fs, and MoCDFs made up the largest proportion (43%) of PCDD/F homologues. The ΣCl 1–3 DD/Fs mainly occurred in the gas phase, while the ΣCl 4–8 DD/Fs mainly occurred in the particulate phase. The majority of ΣCl 1–3 DD/Fs (70%) occurred in d ae > 1.0 μm particles, which is the reverse of the trend observed for ΣCl 4–8 DD/Fs, of which 78% occurred in d ae < 1.0 μm particles. The observed high concentrations of ΣCl 1–3 DD/Fs and different distribution patterns demonstrate that it is necessary to consider the lower chlorinated homologues to improve our understanding of the environmental behavior and health risk assessments of PCDD/Fs in the atmosphere. [ABSTRACT FROM AUTHOR]

A comprehensive comparison of the levels and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in fly ash samples from multiple industrial sources may help to prioritize sources and to understand discrepancies in profiles. In this study, PCDD/F data from 113 fly ash samples from 14 sources reported in previous studies were summarized and compared. The highest PCDD/F levels occurred in samples from secondary copper smelting (SCu). Although PCDD/F levels from secondary zinc smelting (SZn) were slightly lower than those of SCu, the PCDD/F profiles varied widely between the two sources. For SCu, more chlorinated homologs were dominant, with highest degrees of chlorination being 6.6 for PCDF and 7.2 for PCDD. For SZn, less chlorinated homologs were dominant, with lowest degrees of chlorination being 4.4 for PCDF and 4.8 for PCDD. We speculate that copper and zinc might promote PCDD/F formation by catalyzing different pathways of thermal reactions. Diagnostic ratios of specific PCDD/F congeners for different sources were suggested to identify potential sources of PCDD/Fs in the environment. Equations describing correlations between congeners and PCDD/F toxic equivalents were established, which may be useful for rapid and inexpensive screening of the toxic levels of PCDD/Fs in fly ash samples. [ABSTRACT FROM AUTHOR]

The per- and polyfluoroalkyl substances (PFASs) are substantially produced and applied in industrial and domestic products, which have recently aroused great public concern for their potential toxicity to humans. In the present study, raw milk (n = 107) and cow feed samples (n = 70) were collected across nine Chinese provinces, in order to investigate the occurrence of PFASs in milk and feed, and the human exposure risk to milk. The concentrations of PFASs are in the range of < method detection limit −9.82 ng/g dw (average: 1.03 ng/g dw) for milk and 0.99–144 ng/g dw (7.68 ng/g dw) for feed. Perfluorobutanoic acid (34.0%) dominates in feed, while perfluorooctanesulfonic acid (67.5%) dominates in milk. No significant positive correlations of PFASs are observed between paired feed and milk (p > 0.05). However, feeds collected around fluorination production area show relatively higher PFAS levels than those from other areas, which also increase PFAS levels in milk. Risk assessment of PFASs through milk consumption is carried out according to evolving reference doses (RfDs). The hazard quotient is more than one for both adults and children when the strictest RfDs are applied. The Monte Carlo Simulation shows that children face higher PFAS exposure risk than adults. [Display omitted] • PFASs are ubiquitous in feed and milk, with 7.5-fold higher in feed than in milk. • Fluorination production elevate PFAS levels in feed and milk. • PFBA dominates in feed, while PFOS dominates in milk. • Hazard quotients of PFASs are higher for children than adults. [ABSTRACT FROM AUTHOR]

Abstract: In this study, field measurements were conducted to estimate and characterize the atmospheric emission levels and profiles of polychlorinated biphenyls (PCBs) from multiple industrial thermal processes. The emission levels and profiles of PCBs from five types of thermal processes at twenty-three plants were studied and compared with eight processes reported in our previous studies. Correlation analysis was preformed to identify a marker congener for emission of ΣPCB. A significant correlation was observed between congener CB-118 and ΣPCB (R 2 =0.65 and p <0.01), which suggests that CB-118 is a good marker congener for emission of ΣPCB. The profiles of PCBs emitted from the thirteen thermal processes were compared, and this information could be used for studying source–receptor relationships and identifying the specific sources of PCBs. To prioritize the sources for control, the concentrations of PCBs from thirteen industrial thermal sources were compared. The PCB concentrations from secondary zinc smelting and thermal wire reclamation were about one to three order magnitude higher than those of other sources, which suggests that these two sources be given priority in PCB source control. Finally, the atmospheric emission factors of PCBs from the thirteen industrial sources were summarized, and these data will be useful for developing an integrated emission inventory of PCBs. [Copyright &y& Elsevier]

Polychlorinated biphenyls (PCBs) and dibenzo- p -dioxins and furans (PCDD/Fs) are notorious persistent organic pollutants (POPs), which may bioaccumulate through food chain and play detrimental effects to organisms even at trace levels. Quantification of PCBs and PCDD/Fs in biotic samples is a great challenge. In the present study, gas chromatography coupled to triple quadrupole mass spectrometry with an atmospheric pressure chemical ionization source (GC-(APCI)MS/MS) was studied for the isotope-dilution analysis of PCBs (mono-to deca-) and PCDD/Fs in Chinese mitten crab food webs. High-resolution mass spectrometry (HRMS) was applied for comparison. Light PCBs are compared between the two instruments for the first time. After optimization of instrument parameters, the RSDs of relative response factors of calibration curves were between 3.4% and 15.5% for PCBs and 1.7%–7.9% for PCDD/Fs. The limits of detection were between 0.021 and 0.150 pg/mL for PCBs and 0.051–0.237 pg/mL for PCDD/Fs. PCB concentrations in crab food web samples detected by GC-(APCI)MS/MS were well correlated with those detected by HRGC/HRMS. A DiCB, 3,3′-dichlorobiphenyl (PCB11), was the dominant PCB congener in aquatic food webs. Other MoCB and DiCB congeners were also widely identified; hence, low-weight PCB congeners should arouse more concern in the future. GC-(APCI)MS/MS may become an alternative instrument satisfying the PCB and PCDD/F detection. Image 1 • GC-(APCI)MS/MS is compared to HRGC/HRMS for PCB and PCDD/F analyses. • PCBs (mono-to deca-) and PCDD/Fs were investigated. • PCB 11 dominated in Chinese mitten crab food webs. • Light PCBs were frequently detected in Chinese mitten crab food webs. [ABSTRACT FROM AUTHOR]