PCDD/F and DL-PCB exposure among residents upwind and downwind of municipal solid waste incinerators and source identification.

Understanding the environmental and human impacts associated with polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) exposure from municipal solid waste incinerators (MSWIs) is challenging because information on ambient and dietary exposure levels, spatial characteristics, and potential exposure routes is limited. In this study, 20 households from two villages located on the upwind and downwind sides of a MSWI were selected to characterize the concentration and spatial distribution of PCDD/F and DL-PCB compounds in ambient and food samples, such as dust, air, soil, chicken, egg, and rice samples. The source of exposure was identified using congener profiles and principal component analysis. Overall, the dust and rice samples had the highest and lowest mean dioxin concentrations, respectively. Significant differences were observed (p < 0.01) in PCDD/F concentrations in chicken samples and DL-PCB concentrations in rice and air samples between the upwind and downwind villages. The exposure assessment indicated that the primary risk source was dietary exposure, especially from eggs, which had a PCDD/F toxic equivalency (TEQ) range of 0.31-14.38 pg TEQ/kg body weight (bw)/day, leading to adults in one household and children in two households exceeding the World Health Organization-defined threshold of 4 pg TEQ/kg bw/day. Chicken was the main contributor to the differences between upwind and downwind exposure. Based on the established congener profiles, the exposure routes of PCDD/Fs and DL-PCBs from the environment to food to humans were clarified.

Simple and rapid determination of dioxin in fish and sea food using a highly sensitive reporter cell line, CBG 2.8D.

Food, especially animal origin food is the main source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) for human exposure. So, a simple, rapid and cheap bioassay method is needed for determination of dioxins in food samples. In this study, we used a new highly sensitive reporter cell line to determine the concentration of dioxins in 33 fish and seafood samples. The samples were extracted by shaking with water/isopropanol (1:1 v/v) and hexane and cleaned-up by a multi layered silica gel column and an alumina column, then analyzed using CBG 2.8D cell line. We compared the results obtained from the CBG 2.8D cell assay to those obtained from conventional High-Resolution Gas Chromatography-High Resolution Mass Spectrometry (HRGC-HRMS) analysis. Good correlations were observed between these two methods (r2=0.93). While the slope of regression line was 1.76, the bioanalytical equivalent (BEQ) values were 1.76 folds higher than WHO-TEQ values and the conversion coefficient was 0.568 (the reciprocal of 1.76). In conclusion, CBG 2.8D cell assay was an applicable method to determine dioxins levels in fish and sea food samples.

Patterns and dietary intake of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in food products in China.

The health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like PCBs (dl-PCBs) to human being should be assessed regularly. To evaluate the contamination levels in various food products in the Chinese market and to assess the dietary exposure of the Chinese population, 11 varieties of food groups totaling 634 samples including beef and mutton, chicken and duck, pork, fish and seafood, milk and dairy products were evaluated. The average concentrations of PCDD/Fs in all groups ranged from 0.291 to 8.468pg/g whole weight (w.w.). The average toxic equivalency concentrations were from 0.012pg TEQ/g w.w. for cereal to 0.367pg TEQ/g fat for marine oil. OCDD and 2,3,7,8-TCDF were the dominant congeners in foodstuffs. The dietary estimated mean intake for the Chinese rural and urban populations were 0.656 and 0.514pg TEQ/kg body weight/day, respectively, however, the cereal group exposure were higher to the estimate daily intake and contributed 81% for rural and 48% for urban population, followed by fish and seafood which contributed 4% and 16% to the estimate daily intake. The estimated dietary intakes were compared with the toxicological reference values and showed that both rural and urban populations were well below those values.

Level and characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans in feed and feed additives.

Feed security is a prerequisite for safe animal food products. In this study, 13 groups of feed and feed ingredients, totaling 2067 samples, were collected in the period of 2011 to 2014 from China. The highest mean level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was found in fish meals and shell powders, with a concentration of 60.35ng/kg, followed by mineral origin materials. In terms of the toxicity equivalent concentration, the fish oil group showed the highest PCDD/F levels because of their bio-accumulation through the aquatic food chain, with an average concentration of 1.26ng WHO-TEQ/kg, while the lowest level was observed in compound feed for chickens and pigs, with an average value of 0.16ng WHO-TEQ/kg. OCDD and OCDF were the predominant congeners in all groups except fish oils, in which the primary congeners were 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF. For zinc chloride samples, different from other zinc-based compound samples, the main congeners were 1,2,3,4,6,7,8-HpCDF (17%), 1,2,3,4,7,8,9-HpCDF (15%), 1,2,3,4,7,8-HxCDF (12%) and OCDF (30%). Considering toxicity equivalency factors, the dominant congeners were 2,3,4,7,8-PeCDF, 1, 2,3,4,7,8-HxCDF, 2,3,7,8-TCDF and 1,2,3,7,8-PeCDD, and the contribution to the total TEQ was 29%, 16%, 14% and 12%, respectively. Overall, 2.1% (43 out of 2067) of all the analyzed samples exceeded the different individual 'European Union maximum limited levels for PCDD/Fs. This study is beneficial for the determination of the status of contamination levels of feed and feed ingredients.

[Determination of dioxin like polychlorinated biphenyl residues in milk using isotope dilution gas chromatography-ion trap tandem mass spectrometry].

A method for the determination of dioxin like polychlorinated biphenyl (DL-PCB) residues in milk has been developed using high resolution gas chromatography coupled with ion trap mass spectrometry (GC-MS/MS-IT). Analytical procedure consisted of accelerate solvent extraction (ASE), lipid removal with acidic silica and clean-up using anthropogenic isolation column packed with multilayer silica. The analytes were separated on a DB-5 capillary column, detected with multiple reaction monitor mode (MRM) and quantified using internal standard calibration curve of isotope dilution technique. The correlation coefficients of calibration standard solution were above 0. 999 9 for all the DL-PCBs. The recoveries and relative standard deviations of labeled compound solution were in the oranges from 39% to 129% and from 5% to 22%, respectively. The detection limits in the range from 3 to 11 pg/g (fat) were established for the 12 DL-PCBs.

[Rapid and simultaneous determination of thirteen organic phosphorous pesticide residues in spinach using gas chromatography-mass spectrometry coupled with stomach large volume injection and mini solid phase extraction].

A stomach large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) coupled with mini solid phase extraction (SPE) method for the rapid and simultaneous determination of 13 organic phosphorous pesticide residues in spinach samples is presented. The compounds were identified with their retention times and the abundance ratios of qualifier and target ions. Quantification was calculated based on the extraction of spiking standards in a blank sample. The limit of detection (LOD) was determined by the experimental value of the signal-to-noise ratio of 3:1, and the limit of quantification (LOQ) was defined at the experimental value of the signal-to-noise ratio of 10:1. The recoveries obtained ranged from 76.8% to 114.0% with the relative standard deviations between 1.5% and 17.6% except dimethoate. The LODs ranged from 0.5 to 25 microg/kg. This simple, rapid and reliable method has wide applications for the simultaneous determination of multiple pesticide residues in spinach and possibly other species.