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Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) are hazardous industrial chemicals that tend to bioaccumulate in animal-derived foodstuffs through the food supply chain. However, the lack of reliable noninvasive bioindicators hinders the monitoring of farm animal exposure to CPs. In this study, 169 cattle hair samples were collected from beef cattle farms in six Chinese provinces, with further beef, feed, and soil samples being collected in Hebei province. Geographical differences in CP concentrations were observed in the hair samples, and CP concentrations in samples collected from Hebei province decreased in the following order: hair > feed > beef > soil. C 10–11 Cl 6–7 and C 14 Cl 7–8 were the predominant SCCPs and MCCPs, respectively, in all the hair, beef, feed, and soil samples. CP concentrations in hair samples significantly correlated with those in beef, feed, and soil samples, indicating that hair can be used as a bioindicator of cattle exposure to CPs. The possible health risks associated with exposure to CPs through beef consumption, especially for children and high-volume beef consumers, should be further investigated. [Display omitted] • The chlorinated paraffin (CP) contents of cattle hair samples varied geographically. • Higher CP levels were found in hair than in beef, feed, or soil from the same region. • The CP contents of beef, feed, hair, and soil samples correlated significantly. • Hair serves as a noninvasive bioindicator of beef cattle exposure to CPs. • Certain population groups are at risk of CP exposure through beef consumption. [ABSTRACT FROM AUTHOR]

Animal derived foods are the primary pathway for human exposure to polychlorinated naphthalenes (PCNs), and various foodstuffs have been reported to contain PCNs. However, information on how PCN emission sources affect surrounding animal farms is scarce. The present study determined PCN levels in cow's milk, excrement, feed, plant and soil samples collected from four dairy farms situated within 10 km of an iron smelting plant in China. PCN concentrations in the milk samples from all four farms were in the range from 470 to 797 pg/g lipid weight while the PCN concentrations in the other specimens decreased in the order: plant > soil > excrement > feed. Higher PCN concentrations appeared in silage than in other feedstuffs, and the relationships between PCNs in milk, excrement and feed were closer than those in plant and soil. Human exposure risk to PCNs by consuming milk from this region was relatively higher than in less polluted areas. • PCN concentrations in plants and soil were higher than in excrement and feed. • Similar PCN patterns were found in milk, excrement and feed. • PCNs in silage showed higher concentrations than in other feedstuffs. • Tri- and di-CNs were the predominant homologues in all samples. • Relatively high risk posed to humans by PCNs in milk from this region. [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]

Aquatic foods are important sources of chlorinated paraffins (CPs) to humans. Farmed crabs are bottom-dwelling aquatic animals, and can accumulate CPs through food and aquatic environment. However, limited information is available on CPs concentrations in and sources to farmed crabs. In this study, short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) concentrations in 59 samples from the farmed crab food web (crab, crab feed, and aquaculture environment) were determined. The samples were from 17 crab farms in Anhui Province, Jiangxi Province, and Shanghai, in China. The SCCPs and MCCPs concentrations in the crab samples were 82–1760 and not detected–680 ng/g lipid weight, respectively. The dominant SCCPs and MCCPs in the crab samples were C 10 Cl 6−7 and C 14 Cl 7−8 , respectively. The SCCPs concentrations in the crab food web samples were higher than the MCCPs concentrations. SCCPs contamination of the crab food web samples was not directly related to CPs product use. The main factors affecting SCCPs concentrations in the crab samples were different for different crab farms. Crab feed and the aquaculture environment could be sources of SCCPs to farmed crabs. No marked health risks are posed to humans through consuming CPs in Chinese mitten crabs farmed in China. [Display omitted] • SCCP concentrations in farmed crabs were much higher than MCCP concentrations. • Shorter carbon chain and less-chlorinated congeners dominated CPs in farmed crabs. • CP concentrations were highest in samples from the lower Yangtze River reaches. • Crab feed and aquaculture environment could be sources of SCCPs to farmed crabs. • Risks posed to humans through consuming CPs in farmed crabs were low. [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]