Analysis and modelling of profiles to understand fractionation processes for contaminations with polychlorinated biphenyls observed in fish

Polychlorinated biphenyls (PCB) both continue to spread into the environment and to bioaccumulate from primary urban and industrial sources as well as from secondary sources such as soils and the oceans. Fractions of congeners in PCB mixtures, i.e. PCB profiles, can be used as fingerprints to trace contamination pathways from sources to sinks because PCB mixtures fractionate during transport due to congener specific phase changes and degradation. Using a statistical analysis of a total of 8584 PCB profiles with seven congeners (CB28, CB52, CB101, CB118, CB138, CB153, CB180) for contaminated fish from two international datasets as well as a modelling of profiles, two major fractionation processes related to distinct contamination pathways were identified: (1) A relative enrichment of lighter congeners (CB28, CB52, CB101) in seawater fish due to a predominantly atmospheric transport, whereas freshwater and some coastal fish had higher fractions of heavier congeners (CB138, CB153) because those were mainly contaminated by particle-sorbed PCB from surface runoff. (2) A temperature driven fractionation tended to affect congeners with a medium molecular weight (CB118) as well as the heaviest congeners (CB180), a fractionation process which was conceptually associated with transport of PCB from secondary sources. Specifically, medium chlorinated PCB is sufficiently volatile and persistent for a preferred transport into cooler waters. In warmer climates, only the highest chlorinated congeners are persistent enough to ultimately accumulate in fish. Our analysis and modelling provide a starting point for the development of systems to trace - better than before - sources of PCB contaminations observed in fish.

Polyhalogenated carbazoles in indoor dust from Hangzhou, China

Carbazoles (CZ) and polyhalogenated carbazoles (PHCZs), showing dioxin-like toxicity, have gained increasing attention in recent years as novel persistent organic pollutants. However, the occurrence of these chemicals in indoor dust from China remains not well known. In this study, CZ and 11 chloro/bromo CZs were analyzed in indoor dust samples collected from residential houses in rural (n = 51) and urban (n = 55) regions of Hangzhou, China. CZ was detected in all indoor dust samples, with the concentrations of 0.81-18 ng/g (mean 5.4 ng/g). All 11 measured PHCZs were detected in indoor dust samples, showing the detection frequency of 7.3-96 %. This means that general populations had wide exposure to CZ and PHCZs through indoor dust ingestion. 3,6-dichlorocarbzole (36-CCZ) and 3,6-dibromocarbazole (36-BCZ) were the predominant PHCZs in indoor dust, having comparable mean concentrations of 1.2 ng/g, followed by 3-monobromocarbazole (3-BCZ; mean 0.66 ng/g, range < LOD-2.1 ng/g) and 1,3,6-tribromocarbazole (136-BCZ; 0.36 ng/g, < LOD-1.0 ng/g). Indoor dust concentrations of 3-BCZ, 36-BCZ, and 1,3,6,8-tetrabromocarbazole in urban regions were significantly (p ≤ 0.01-0.035) higher than that in rural regions. Daily intakes (DIs) of CZ and PHCZs through indoor dust ingestion were estimated for general Chinese population. Among PHCZs, 36-CCZ and 36-BCZ (mean 1.4-3.4 pg/kg bw/day) had the highest mean DIs, followed by 3-BCZ (0.77-1.9 pg/kg bw/day) and 136-BCZ (0.42-1.0 pg/kg/day). To our knowledge, this is the first study reporting the concentrations of CZ and PHCZs in indoor dust from China, which contributes to the better understanding of the sources of human exposure to CZ and PHCZs.

Juvenile harbor porpoises in the UK are exposed to a more neurotoxic mixture of polychlorinated biphenyls than adults

Polychlorinated biphenyls (PCBs) are a group of 209 persistent and bio-accumulative toxic pollutants present as complex mixtures in human and animal tissues. Harbor porpoises accumulate some of the highest levels of PCBs because they are long-lived mammals that feed at a high trophic level. Studies typically use the sum of a suite of individual chlorobiphenyl congeners (CBs) to investigate PCBs in wildlife. However, toxic effects and thresholds of CB congeners differ, therefore population health risks of exposure may be under or over-estimated dependent on the congener profiles present. In this study, we found congener profiles varied with age, sex and location, particularly between adult females and juveniles. We found that adult females had the highest proportions of octa-chlorinated congeners whilst juveniles had the highest proportions of tri- and tetra-chlorinated congeners. This is likely to be a consequence of pollutant offloading between mothers and calves during lactation. Analysis of the individual congener toxicities found that juveniles were exposed to a more neurotoxic CB mixture at a time when they were most vulnerable to its effects. These findings are an important contribution towards our understanding of variation in congener profiles and the potential effects and threats of PCB exposure in cetaceans.

Occurrence and congener profiles of polybrominated diphenyl ethers in green mussels (Perna viridis) collected from northern South China Sea and the associated potential health risk

Polybrominated diphenyl ether (PBDE) contamination has become a major concern over the effects on human health. In the present study, we collected widely consumed green mussels (Perna viridis) samples from the northern South China Sea (NSCS) to investigate the occurrence, spatial distribution, congener profiles as well as potential risk of 18 PBDEs. All the target PBDEs were detected in green mussel samples, indicating their ubiquitous distribution. The concentrations of the total 18 PBDE_S (ΣPBDEs) in all samples varied from 6.96 to 55.6 ng/g lipid weight (lw), with BDE-47 and BDE-209 being the predominant PBDE congeners. Overall, the ΣPBDEs pollution in green mussels from NSCS was at a moderate to high level in comparison with the PBDEs pollution worldwide. The dietary exposure of the local population in South China to PBDEs via consuming green mussels was estimated to be 0.30-0.80 ng/kg body weight (bw)/day. Evaluation of the exposure risk for BDE-47, 99, 153 and 209 indicated that health risks due to green mussel consumption are substantially lower than the U.S. EPA minimum concern level.

Spatial Distribution and Congener Profiles of Polybrominated Diphenyl Ethers in Surface Sediment from Sanmen Bay and Xiamen Bay, Southeast China

Coastal areas are influenced by anthropogenic input of a variety of organic pollutants, among which polybrominated diphenyl ethers (PBDEs) represent an important group. In the present study, we investigated the contamination status of PBDEs in surface sediment from two economically important Bays in Southeast China, Sanmen Bay (SMB; n = 29) and Xiamen Bay (XMB; n = 10). Concentrations of ∑PBDEs ranged from 2.2 to 78.5 ng/g dw (median 5.7 ng/g dw) in SMB and 7.9-276.0 ng/g dw (median 43.5 ng/g dw) in XMB, respectively. A nearshore-offshore decreasing trend was observed for both ∑PBDEs and BDE-209 concentrations, indicating strong urban influences. Although the current levels would not produce any significant impact on benthos and aquatic ecosystems of the studied regions, continuous monitoring is needed to understand the temporal trends of contamination in the important coastal waters and whether sediment-associated PBDEs constitute a potential source to aquatic ecosystems.

Polyhalogenated Carbazoles in Surface Sediment from Sanmen Bay, East China Sea: Spatial Distribution and Congener Profile

Polyhalogenated carbazoles (PHCZs) have recently emerged as a group of halogenated pollutants with broad occurrences and bioaccumulation potential in aquatic systems. However, investigations on their occurrences in coastal waters remain very limited. In the present study we investigated PHCZs in surface sediment collected from 29 sites in Sanmen Bay, East China Sea. The results demonstrated a universal presence of PHCZs in sediment, with concentrations of ∑PHCZs (including all congeners) ranging from 7.7 to 17.5 ng/g dry weight (median: 11.3 ng/g dw). The PHCZ congener composition profile revealed a dominance of 3,6-dichlorocarbazole (36-CCZ) with comparable concentration with that of carbazole. Given that PHCZs are widely distributed in Sanmen Bay sediment and their concentrations rivaled other well-known persistent organic pollutants in the same area, this group of halogenated pollutants merits additional investigations of their potential risks to the studied aquatic system, as well as other important watersheds.

Persistent halogenated organic pollutants in follicular fluid of women undergoing in vitro fertilization from China: Occurrence, congener profiles, and possible sources

Analysis of persistent halogenated organic pollutants (HOPs) in human follicular fluid is important given previous reports of their adverse effects on the reproductivity of women. In the present work, HOPs, including polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), were analyzed in 127 follicular fluid samples collected from patients who were undergoing in vitro fertilization in Central China. The concentrations of ∑₇BDEs (sum of BDE-28, -47, -99, -100, -153, -154, and -183) in follicular fluid ranged from not detected (n.d.) to 110 ng/g lipid weight (lw), with an average of 50 ± 24 ng/g lw. BDE-100 was suggested to be an indicator of BDE congeners in follicular fluid, with the highest concentrations and showing a significantly high correlation (p < 0.01) with ∑₇BDEs. Penta-BDE products were the principal source of PBDEs in follicular fluid samples. The concentrations of ∑₇CBs (CB-28, -52, -101, -118, -138, -153, and -180) in follicular fluids ranged from n.d. to 250 ng/g lw, with an average of 77 ± 69 ng/g lw. CB-28 and CB-52 were considered to be indicator CB congeners, with tri-CBs and tetra-CBs dominating in follicular fluid. No significant correlation was observed between patient age and PBDE or PCB concentrations in follicular fluid, indicating that age was not the controlling factor influencing the bioaccumulation of most HOPs in this study.

Source identification and quantification of chlorinated and brominated polycyclic aromatic hydrocarbons from cement kilns co-processing solid wastes

Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are widespread persistent organic pollutants (POPs) in environments. Identifying the new sources of Cl/Br-PAHs is important for implementing source control and reducing environmental risk. Although co-processing of solid wastes by cement kilns increased recently, the occurrences and characteristics of Cl/Br-PAHs as emerging POPs during cement kiln co-processing solid wastes have not been investigated. This study firstly investigated the occurrences, characteristics, and variations of Cl/Br-PAHs from four cement kilns co-processing different solid wastes. The concentration ranges of Cl-PAHs and Br-PAHs in stack gas samples from the investigated cement kilns were 15.6-94.1 ng m^-3 and 1.04-4.28 ng m^-3, respectively. Emission factors of Cl-PAHs and Br-PAHs through stack gases were 29.9-275 μg t^-1 and 3.0-8.3 μg t^-1, respectively. Variations of Cl/Br-PAHs in particle samples collected from different process stages within the cement kiln system indicated that the kiln end was the major formation zone for Cl/Br-PAHs. Congener profiles of Cl/Br-PAHs varied with the co-processed solid waste types, indicating the important influence of raw material compositions. Calculations of net emissions of Cl/Br-PAHs within the cement kiln systems suggested efficient destruction (87.6%-98.8%) of Cl/Br-PAHs by the cement kilns.

Levels, congener profiles, and dietary intake assessment of polychlorinated dibenzo-p-dioxins/dibenzofurans and dioxin-like polychlorinated biphenyls in beef, freshwater fish, and pork marketed in Guangdong Province, China

Persistent organic pollutants such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) consisting of non-ortho and mono-ortho PCBs are suggested to be very hazardous and have adverse effects on human health. However, their levels and congener profiles in retail foods marketed in Guangdong Province of China have not been elucidated thus far. Thus, in this study, 226 individual samples of beef, freshwater fish, and pork marketed across four regions of Guangdong Province were randomly collected during 2013-2015 to determine their levels of PCDD/Fs and DL-PCBs. The results showed that the total toxic equivalency quantities (TEQs) of most samples were below the maximum limits except for the 26 samples collected from the vicinities of pollution areas. The median total TEQs of these three categories were 0.174, 0.488, and 0.113pgTEQ/g fw, respectively, which indicated that the contamination status of the studied foods was not serious. For congener profiles, significantly different patterns were observed in three food groups, but with the same major TEQ contributors being 2,3,4,7,8-PeCDF in beef, freshwater fish, and pork. Regional differences of congener profiles in each food group were also found in this study, which might be attributed to the regionally different distributions of PCDD/Fs and DL-PCBs in environment media. The dietary exposures of four population subgroups (girls, boys, male adults, and female adults) to PCDD/Fs and DL-PCBs via three food groups were estimated to assessed the potential risks. They were all lower than the provisional tolerable monthly intake (PTMI, 70pgTEQ/kgbw/month) established by Joint FAO/WHO Expert Committee on Food Additive. In these food categories, the exposure to PCDD/Fs and DL-PCBs via freshwater fish was the highest one, which accounted for about 20% of PTMI, indicating that it was the major route to expose dioxin compounds.

Long-term sampling of dioxin-like substances from a clinker kiln stack using alternative fuels

The aim of this work is to characterize atmospheric emissions of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) from a cement production plant where the existing clinker production line was completely replaced by a new state-of-the-art installation. The project started in April 2008 with the installation of a long-term sampling system in the stack of the clinker kiln that used petroleum coke as fuel; PCDD/PCDF and dl-PCB emissions were then evaluated for a two year period. To carry out the second part of the study, in 2010 the sampling system was moved to the new installation in which, apart from conventional fuel, recovered derived fuel (RDF) and WWTP sludge were used as alternative fuels. For both the old and new clinker kilns, PCDD/PCDF emission values were well below the limit established by the European Waste Incineration Directive 2000/76/CE (EWID) of 100 pg I-TEQ/Nm(3); values ranged from 0.43 to 2.02 and from 0.07 to 3.31 pg I-TEQ/Nm(3), respectively. dl-PCBs accounted for approximately 25% of the WHO-TEQ toxicity. These results prove that the installation is capable of reducing PCDD/PCDF and dl-PCB emissions when alternative fuels are integrated into the process. In the case of PCDDs/PCDFs, the major contributions to total TEQ were usually from 2,3,7,8-TCDD (owing to its relative abundance) and 2,3,4,7,8-PeCDF (due to its high I-TEF of 0.5); while for dl-PCBs, the major contribution was from PCB-126. The slight shift in the congener profile between the old and new installations was characterized and a regression model was proposed for dl-PCB emissions depending on the RDF flow rate in the clinker.

Cucurbita spp. and Cucumis sativus enhance the dissipation of polychlorinated biphenyl congeners by stimulating soil microbial community development

A number of Cucurbita species have the potential to extract polychlorinated biphenyls (PCBs) from soil, but their impact on the soil microbial communities responsible for PCB degradation remains unclear. A greenhouse experiment was conducted to investigate the effect of three Cucurbita and one Cucumis species on PCB dissipation and soil microbial community structure. Compared to the unplanted control, enhanced losses of PCBs (19.5%-42.7%) were observed in all planted soils. Cucurbita pepo and Cucurbita moschata treatments were more efficient in PCB dissipation, and have similar patterns of soil phospholipid fatty acids (PLFAs) and PCB congener profiles. Cucurbita treatments tend to have higher soil microbial biomass than Cucumis. Gram-negative (G(-)) bacteria were significantly correlated with PCB degradation rates (R(2) = 0.719, p < 0.001), while fungi and G(-) bacteria were correlated with dissipation of the penta homologue group (R(2) = 0.590, p < 0.01). Therefore, Cucurbita related soil microorganisms could play an important role in remediation of PCB contaminated soils.

Serum concentrations of polybrominated diphenyl ethers (PBDEs) and a polybrominated biphenyl (PBB) in men from Greenland, Poland and Ukraine

Many brominated flame retardants (BFRs)-including polybrominated diphenyl ethers (PBDEs)-have been shown to persist in the environment, and some have been associated with adverse health effects. The aim of the present study was to quantify serum concentrations of common brominated flame retardants in Inuit men from across Greenland, and in men from Warsaw, Poland and Kharkiv, Ukraine. Serum was sampled between 2002 and 2004 from men 19 to 50years of age. 299 samples were analyzed for BDE-28, 47, 99, 100, 153, 154 and 183 and the brominated biphenyl BB-153 using gas chromatography-high resolution mass spectrometry. BDE-47 and BDE-153 were detected in more than 95% of samples from all three populations. All other congeners, except BDE-154, were detected in more than 70% of samples from Greenland; lower detection frequencies were observed in Polish and Ukrainian samples. Concentrations of individual congeners were 2.7 to 15 fold higher in Greenlandic relative to Polish and Ukrainian men. Geometric mean concentrations of the sum of the most abundant PBDEs of the Penta-BDE commercial mixture (BDE-47, 99, 100, 153 and 154) were 6.1, 1.7 and 0.87ng/g lipids in the Greenlandic, Polish and Ukrainian men, respectively. Furthermore, significant geographical differences in BFR concentrations were observed within Greenland. Principal component analysis revealed distinct clustering of samples by country of origin. The associations between ΣPBDEs and age were inconsistent, varying from no association in Greenlandic and Polish study populations to a U-shaped relationship in Ukrainians. We report BFR levels for three populations for which sparse biomonitoring data exists.

Polybrominated diphenyl ethers (PBDEs) in the surface sediments and suspended particulate matter (SPM) from Lake Chaohu, a large shallow Chinese lake

Suspended particulate matter (SPM) and surface sediment samples were collected from Lake Chaohu to investigate the residues, congener profile, and spatial distribution of polybrominated diphenyl ethers (PBDEs) in a large shadow lake in the middle of the Yangtze River Basin. The concentration of Σ13BDEs (defined as the sum of 13 target congeners excluding BDE 209) and the concentration of BDE 209 ranged from 236.7 to 1373.4 pg/g dry weight (dw) and from 4.2 to 691.2 pg/g dw in the surface sediments, respectively, which were 2-3 orders of magnitude smaller than those found in the SPM. The congener composition was dominated by BDE 47 (50.8%) and BDE 209 (21.3%) in the sediment, while the proportion of BDE 47 to Σ14BDEs in the SPM was slightly higher than that in the sediment. The concentration of Σ14BDEs in the sediment from the drinking water source (WR) area in the eastern part of the lake was very low, with a mean value of 514.8 pg/g, whereas the mean concentration was 102.4 ng/g in the SPM. A cluster analysis (CA) was conducted to further illustrate the dominance of each congener and the similarity of each sampling site. Many factors, including resuspension, photodecomposition, microbial oxidation, local discharge, and dredging, influenced the distribution in the sediment and SPM for the PBDE congeners as well as the spatial distribution of PBDEs. A formula for the PBDE concentrations in the surface sediment and SPM was constructed to understand the potential relationship between sediment and SPM concentrations. Although the formula did not accurately predict specific PBDE congener concentrations in the sediment, it remains a practical and useful way to assess the overall pollution of PBDE in sediment in Lake Chaohu, as it depends only on the concentrations of PBDEs in the SPM.