Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands

The residues and health risk assessment of polychlorinated biphenyls (PCBs) in Pheretima (an earthworm-derived traditional medicine) from southeastern China

Minimal research exists on polychlorinated biphenyl (PCB) exposure from traditional Chinese medicines (TCMs), despite their significant contributions to domestic and international health protection. This study is the first to investigate the levels, profiles, and health risks of PCB residue in Pheretima, a typical TCM produced from earthworm. Seventy-seven Pheretima samples from different regions of China were analyzed for 45 PCB congeners. PCBs were found in all samples exhibiting species-dependent discrepancies. ∑45PCBs was ranging from 0.532 to 25.2 µg/kg (mean 4.46 µg/kg), with CB-11 being the most abundant congener contributing 71.8% ± 10.8% to ∑45PCBs, followed by CB-47, which were all non-Aroclor congeners called unintentionally produced PCBs (UP-PCBs). The average estimated daily intake of ∑45PCBs, ∑7ID-PCBs (indicative polychlorinated biphenyls), and CB-11 were 0.71, 0.04, and 0.51 ng/kg bw/d, respectively. The ∑HQ of PCBs in Pheretima samples was 2.97 × 10-4-2.46 × 10-2 (mean 2.77 × 10-3, 95th 4.21 × 10-3), while the ∑RQ ranged from 1.19 × 10-8 to 2.88 × 10-6 (mean 4.87 × 10-7, 95th 2.31 × 10-6). These findings indicate that Pheretima ingestion does not pose significant non-carcinogenic risks. However, certain individual samples exhibit an acceptable level of potential risks, particularly when considering that PCBs are recognized as endocrine disruptors and classified as probable carcinogens. These results contribute to the safety evaluation of traditional medicines and suggest the potential use of Pheretima as a bioindicator for PCB pollution. It is advisable to monitor UP-PCBs as indicator congeners and gather additional toxicological data.

Phytoremediation of dinitrophenol from wastewater by atriplex lentiformis: effect of salicylic acid

Quail bush [Atriplex lentiformis (Torr.) S. Wats] plants were used in removing 2, 4-dinitrophenol (DNP) from wastewater in a hydroponic experiment. The hydroponic system contained three doses of DNP, i.e., 0, 10, and 20 mg L-1. Quail bush plants were sprayed with 0.1 mM salicylic acid (SA) to study its role in resisting DNP toxicity. DNP significantly (p < 0.05) reduced plant growth. Exposure of A. lentiformis plants to 20 mg L-1 of DNP reduced the total chlorophyl and relative water content by 39 and 24%, respectively. SA improved the antioxidant defense in terms of ascorbate peroxidase (APX) and polyphenol oxidase (PPO) activities. SA alleviated DNP toxicity by enhancing the production of osmoprotectants, e.g.,proline, phenols, and carbohydrates. SA enhanced the removal efficiency of DNP and the highest removal efficiency (96%) was recorded in the plants sprayed with SA and grown on 10 mg L-1 of DNP. A. lentiformis is a halophytic plant that has good physiological characteristics to resist 2, 4-dinitrophenol toxicity in wastewaters and is qualified to purify water from these harmful compounds. Exogenous application of 0.1 mM SA increased the defense system in A. lentiformis against 2, 4-dinitrophenol toxicity and enhanced the removal efficiency.

Occurrence and Source Identification of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans and Polychlorinated Biphenyls in Surface Sediments from Liangshui River in Beijing, China

Polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls were measured in the surface sediments of Liangshui River, the second largest drainage river in Beijing, China. The sum concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls ranged from 3.5 to 3019 (mean value: 184) pg g^-1 dry weight and from 319 to 5949 (mean value: 1958) pg g^-1 dry weight, and the corresponding World Health Organization toxic equivalent quantity values were 0.0011-5.1 pg TEQ g^-1 dry weight and 0.0074-1.4 pg TEQ g^-1 dry weight, respectively. The spatial distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls showed increasing trends from urban area and development area to suburb. Principal component analysis revealed that polychlorinated dibenzo-p-dioxins and dibenzofurans contamination in the sediments may originate from pentachlorophenol and sodium pentachlorophenate and municipal solid waste incineration. Regarding polychlorinated biphenyls, the steel industry, combustion processes and usage of some commercial polychlorinated biphenyl products were identified as the major sources. The emission from a former steel plant could be the main contributor to polychlorinated biphenyls in urban areas. The mean value of the total toxic equivalent quantities in the sediment samples exceeded the Canadian interim sediment quality guidelines. Long-term wastewater irrigation increases the load of sediment-bound pollutants in agricultural soil and may pose potential ecological risks to crops and human health.

Tolerance of phyllospheric Wickerhamomyces anomalus to BDE-3 and heavy metals

Few research have focused on the potential microorganism and gene resources for plant resistance to polybrominated diphenyl ether (PBDE) and heavy metal (HM) co-contamination. The purpose of this study was to investigate the impact of phyllospheric Wickerhamomyces anomalus bioremediation ability on PBDE and HM co-contamination. The results showed that the toleration capability of W. anomalus to cadmium (Cd2+) was higher than that to chromium (Cr) or 4-bromodiphenyl ether (BDE-3) contamination. The threshold levels of W. anomalus tolerance to BDE-3, Cd2+, and Cr were 30 mg/L, 500 mg/L, 30 mg/L, respectively. The use of the higher concentration of BDE-3 (30 mg/L) as a carbon source may improve tolerance to Cd2+ and Cr (10 mg/L Cd2+ and 10 mg/L Cr). Overexpression of Wapdr15 gene of ABCG subfamily from W. anomalus improved the tolerance to BDE-3 (10 mg/mL) and Cd2+ (0.5 mg/mL) significantly in transgenic tobacco lines. The synergism effect of BDE-3 and Cd2+ stress existed similarly in W. anomalus and transgenic lines. The findings suggest that W. anomalus should be taken into account for providing an efficient method in improving crops' tolerance during PBDE and HM co-contamination in soil.

Melatonin relieves 2,2,4,4-tetrabromodiphenyl ether (BDE-47)-induced apoptosis and mitochondrial dysfunction through the AMPK-Sirt1-PGC-1α axis in fish kidney cells (CIK)

Polybrominated diphenyl ethers (PBDEs) exist in aquatic environments with nephrotoxicity to non-target aquatic species. Melatonin (MT) exhibits an inhibitory effect of oxidative stress and apoptosis in various diseases. 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) is the main homolog of PBDE samples. Therefore, we investigated the toxic mechanism of BDE-47 and the alleviation effect of MT, the ctenopharyngodon idellus kidney (CIK) cells were treated with BDE-47 (100 μM) and/or MT (60 μM) for 24 h. Firstly, BDE-47 exposure could inhibit oxidative stress-related antioxidant enzymes (T-AOC, SOD, CAT and GPx) and increase the content of malondialdehyde (MDA) to cause oxidative stress. Secondly, BDE-47 enhanced mitochondrial division and inhibited fusion to induce mitochondrial membrane potential in CIK cells. BDE-47 enhanced the mRNA and protein levels of mitochondrial-pathway apoptosis related genes (Cas 3, Cyt-c, and BAX). Thirdly, BDE-47 treatment decreased the expression levels of mitochondrial-related regulatory factors AMPK-Sirt1-PGC-1α signal pathway. Intriguingly, BDE-47-induced oxidative stress, mitochondrial pathway apoptosis and mitochondrial dynamics disorder could be alleviated by MT treatment. Overall, we concluded that MT could relieve BDE-47-induced oxidative stress, mitochondrial dysfunction and apoptosis through the AMPK-Sirt1-PGC-1α axis. These results enrich the mechanisms of BDE-47 poisoning and reveal that MT treatment may be a potential strategy for solving BDE-47 poisoning.

Interaction between polychlorinated biphenyls and dissolved organic matter of different molecular weights from natural and anthropic sources

Polychlorinated biphenyls (PCBs) are compounds of significant interest due to high toxicity, persistence, long-range atmospheric transport, and bioaccumulation. These compounds can interact with components present in the environment, including dissolved organic matter (DOM) in soils and waters, thereby modifying its availability and movement. In this study, DOM was fractionated by ultrafiltration and characterized according to its hydrophobicity and hydrophilicity, then the interaction of a series of PCBs and different DOM fractions was evaluated. The DOM was collected from the surface waters of three sectors located along a river in the southern part of America. These sectors are subject to different anthropic activities, thus the DOM of sector 1, with the least anthropic influence, was mainly hydrophobic and with a high content of aromatic structures. In contrast, the DOM collected from sectors 2 and 3, where anthropic activity is highest, was slightly hydrophobic and hydrophilic, respectively. The DOM of these two sectors was mainly composed of low molecular weight macromolecules. These results revealed that more hydrophobic PCBs (i.e., 101, 118, 138, and 180) have a greater affinity to DOM with a higher molecular weight (i.e., >1 kDa). In turn, PCBs with lesser chlorination and hydrophobicity presented a greater affinity to DOM with a lower molecular weight. In conclusion, our study shows that the high molecular weight DOM is responsible for mobilizing PCBs with a high degree of chlorination.

The photosynthetic physiological response and purification effect of Salix babylonica to 2, 4-dinitrophenol wastewater

Phytoremediation technology based on living green plants would clean up water pollution. Through hydroponic experiment, the effects of different concentration of 2, 4-dinitrophenol (2, 4-DNP) on the photosynthetic and chlorophyll fluorescence parameters of Salix babylonica, and the absorption and purification effect of S. babylonica on 2, 4-DNP were measured to explore the tolerance of S. babylonica to 2, 4-DNP and the feasibility to purify dinitrophenol waste water by it. The biomass, actual photochemical efficiency (PSII), net photosynthetic rate (Pn), photochemical quenching coefficient (qP), stomatal conductance (Gs), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm) and chlorophyll content of the S. babylonica showed downward trend with the increasing exposure concentrations of 2,4-DNP, but the intercellular CO₂ concentration (Ci) appeared upward trend. Non-photochemical quenching coefficient (NPQ) increased at 5 mg L^-1, then declined with the increase concentrations of 2, 4-DNP. In addition, the percent removal of 2, 4-DNP in 20 mg L^-1 waste water was 91.4%. In conclusion, 2, 4-DNP significantly inhibits Pn of S. babylonica and the reduction of Pn was caused by decreasing Gs, carboxylation efficiency and chlorophyll content. When the concentration of 2, 4-DNP is not more than 20 mg L^-1, S. babylonica can remove 2, 4-DNP efficiently.

Short-chain chlorinated paraffins in soils indicate landfills as local sources in the Tibetan Plateau

Background contamination levels of contemporary persistent organic pollutants (POPs) may be elevated due to local discharges, and hence it is of high importance to assess and monitor them in alpine and Polar Regions. This study investigated the role of waste disposal in the Tibetan plateau as the local source of short-chain chlorinated paraffins (SCCPs). SCCPs were determined in soils from the urban landfill and rural dumpsites, with a concentration range of 56.8-1348 ng/g dw. The gradient descent of SCCP levels from Lhasa landfill to the surrounding soils with increasing distances suggested a significant SCCP release from waste disposal. The transport pattern was well fitted by the Boltzmann equation after normalization in terms of soil organic carbon contents. Compared to the landfill cells closed in early years, the recently closed cells contained higher concentrations but lower proportions of the short-chain congener groups, likely reflecting the SCCP use history in Tibet. In open-burning dumpsites, higher SCCP levels and dominance of lighter congener groups indicates that such crude waste treatment process might cause an extra release of volatile SCCPs. This study elucidates local SCCP inputs to the background environment, and demonstrates that both urbanization and badly-managed landfill have been contributing to the presence of contemporary POPs in the Tibetan Plateau.

PCB vertical and horizontal movement in agricultural soils of a highly contaminated site: Role of soil properties, cultivation history and PCB physico-chemical parameters

The agricultural areas of a historically contaminated National Relevance Site (SIN Brescia Caffaro) in Italy are an ideal case for studying the long term vertical and horizontal movement of polychlorinated biphenyls (PCBs) in soil. Here, a former large producer of PCBs (Caffaro S.p.A.) discharged its wastewaters, contaminated by PCBs and other chemicals, to a ditch used for about 80 years as source of irrigation waters for the adjacent agricultural areas. This caused a spread of contamination along both a vertical and a horizontal soil gradient. PCB concentrations of about 80 congeners, including PCB 209, peculiar of Caffaro production, were measured in three areas, selected for their different soil properties and cultivation history. The contamination levels with depth ranged from about 30 mg/kg dry weight (d.w.) of soil in the top (plow) layer to less than 0.1 mg/kg d.w. at the depth of 1 m. The concentrations varied also horizontally, since each field was surface irrigated from the short edge of each field, showing that PCBs could spread with length halving the initial concentrations in the topsoil only after about 30-35 m. The concentration gradients detected were explained considering the historic soil use and its change with time, the pedological properties as well as PCB physico-chemical parameters and halflives, developing equations which could be employed as guidance tools for evaluating PCBs (and similar chemicals) movement and direct further studies.

Markers of polychlorinated biphenyl (PCB) degradation in highly contaminated soil of Central Russia

The highly polychlorinated biphenyl (PCB)-contaminated historical soil is located in the Serpukhov region (Central Russia). This study evaluates the processes of PCB degradation in the soil under natural conditions. Compositions of industrial mixtures (Sovol, Sovtol, and trichlorodiphenyl) were compared with PCB-contaminated soil from different depths. An increased number of dichlorobiphenyls (6 congeners) were determined in the deeper soil horizons (40-60 cm) in comparison with the surface layer (1 congener). Non-associated with industrial mixture congener, PCB 11 was determined in some soil layers with concentrations reaching 3.6 mg/kg. PCB 11 can be considered as a potential marker of activated degradation processes in highly contaminated soils with industrial mixtures. Aegopodium podagraria reduced total PCB concentrations in the contaminated soil to 25% during pot experiments. Prospective precursors of PCB 11 were significantly depleted (62-88%) after phytoremediation, but this did not increase PCB 11 concentration in the soil.

Concentrations and risks of polychlorinated biphenyls (PCBs) in transformer oils and the environment of a power plant in the Niger Delta, Nigeria

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Soils and water resources around the power plant are contaminated with PCBs.

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The hepta- and octa-PCB homologues were dominant in the samples.

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Exposure to PCBs in soils from the power plant could cause human health risk.

The concentrations of Ʃ14 PCBs were determined, with the aid of gas chromatography-mass spectrometry (GC–MS), in transformer/turbine oils, soils, groundwater, and drainage water collected within a power plant in the Niger Delta of Nigeria. The Ʃ14 PCB concentrations in the transformer oils, drainage water, groundwater and soils ranged from 484 to 48506 mg kg⁻¹, 0.99 to 2.95 mg L⁻¹, 0.16 to 0.56 mg L⁻¹ and from 8.4 to 510 mg kg⁻¹ respectively. The congener distribution patterns in these samples indicate the dominance of highly chlorinated homologues (hepta- and octa-PCBs). The Σ14 PCB concentrations in the transformer oils were above the provisional definition of low persistent organic pollutant (POP) content for PCBs of 50 mg kg⁻¹ as defined in the guidelines on the management of POP waste of the Basel Convention. The concentrations of Ʃ14 PCBs in the soils were above the Dutch guideline value of 1000 μg kg⁻¹ and the estimated incremental lifetime cancer risks relating to exposure of humans to PCBs in soils indicate serious health risks. There is therefore a need to implement a surveillance programme in the vicinity of power plants to determine the impacts on the adjacent ecosystem.

Polybrominated diphenyl ethers in the dissolved and suspended phases of seawater from Sanggou Bay, east China

The levels and profiles of polybrominated diphenyl ethers (PBDEs) in dissolved phase (DP) and suspended particulate matter (SPM) in seawater of Sanggou Bay (SGB) in four seasons were determined. The distribution and potential sources of these compounds were analyzed, and the ecological risk was assessed. The total concentrations of 14 PBDEs (∑₁₄PBDE) in DP and SPM in the surface water ranged from 0.10 ng L^-1 to 2.20 ng L^-1 and from 0.51 ng L^-1 to 6.15 ng L^-1, respectively. The highest value was obtained in August. The concentrations of ∑₁₄PBDE in the surface water were higher than those in the bottom water, and PBDEs were mainly partitioned into the SPM fraction. BDE209 was the most dominant PBDE congener, having average relative contributions of 86.5%-94.8% in DP and 40.5%-56.5% in SPM, followed by BDE47. The profiles of PBDEs in seawater of SGB were different from those of commercial PBDE products. The concentrations of ∑₁₄PBDE were higher in the inner bay than in the outer bay, suggesting that the terrestrial input and human activities affected the PBDE distribution in SGB. Results of nonparametric multidimensional scaling suggested that BDE209 and BDE47 were important congeners discriminating PBDE contamination in SGB. The potential sources of PBDEs in SGB included commercial PentaBDE and DecaBDE products from the land, the atmospheric transport of commercial OctaBDE, and the degradation of high brominated congeners. The ecological risks from PentaBDE and OctaBDE were low, and those from DecaBDE were moderate in seawater of SGB.

Levels and distribution of polybrominated diphenyl ethers in the aquatic and terrestrial environment around a wastewater treatment plant

The distribution and fate of polybrominated diphenyl ethers (PBDEs) in a riparian ecosystem nearby a wastewater treatment plant effluent were investigated. Different aqueous and terrestrial samples such as soil, sediment, plants, and invertebrates were collected and analyzed for tri- to heptabrominated PBDEs. Furthermore, the food web structure was elucidated using stable carbon and nitrogen isotopes. The highest PBDE levels were found for sediment- and soil-dwelling invertebrates, such as earthworms (Σ13 PBDEs 144 ng/g lipid weight), Tubifex tubifex (77 ng/g lw), and scarab larvae (49 ng/g lw). Differences in congener composition profiles among the different matrices show that the environmental distribution and fate of PBDEs in ecosystems can be very complex. Among the analyzed PBDEs in this ecosystem, the tetra-brominated BDE-47 was the dominant PBDE congener and followed by the penta-brominated BDE-99. A potential trend of increasing BDE-47/99 ratio with the increase of δ(15)N was observed for species with similar energy sources (δ(13)C), indicating a higher bioaccumulation potential for BDE-47 in this ecosystem. A significant correlation was also found between PBDEs and polychlorinated biphenyls (PCBs), indicating similar sources and fate between the two compound groups in this area. The biota-soil or biota-sediment accumulation factors (BSAFs) were somewhat different among the PBDE congeners and species, but were generally highest for those with log Kow values around 6.5-7.

Occurrence and distribution of PAHs, PCBs, and chlorinated pesticides in Tunisian soil irrigated with treated wastewater

Treated wastewater (TWW) is a well recognized source of organic pollutants (OPs) that may accumulate during irrigation. For the first time, data on the occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyles (PCBs) and organochlorinated pesticides (OCPs) in wastewater irrigated soil in Nabeul (Tunisia) are reported. 13 PAHs, 18 PCBs and 16 OCPs were analyzed in soil samples collected at 0-10 and 10-20 cm depth before each and every irrigation and after the irrigation period expanding from June to October. Soil was extracted with an accelerated solvent extractor and analyzed by a tandem gas chromatograph in selected reaction monitoring mode (GC/MS/MS/SRM). OPs residues were detected before irrigation and accumulated at the end of the season for some of them. The total concentration of PAHs varied between 120.01 and 365.18 μg kg(-1) dry weight (dw) at 0-10 cm depth before and at the end of irrigation, respectively. The total concentration of PCBs varied between 11.26 and 21.89 μg kg(-1) dw at 0-10 cm, being higher than those reported for 10-20 cm. The six indicator PCB congeners (28, 52, 101, 138, 153, 180) were predominant. OCPs concentrations ranged between 12.49 and 21.81 μg kg(-1) at 0-10 cm and between 74.03 and 310.54 μg kg(-1) at 10-20 cm depth. DDT was predominant accounting for more than 94% of the total OCPs. In view of the present results, OPs are relevant to the agricultural environment, calling for more research on their persistence and potential transfer to plants and/or groundwater while taking into account farmers' practices.

Field study on the uptake and translocation of PBDEs by wheat (Triticum aestivum L.) in soils amended with sewage sludge

Field experiments were conducted to explore the effects of different sewage sludge amendment strategies on the accumulation and translocation of polybrominated diphenyl ethers (PBDEs) in soil-wheat systems. Two types of application methods (single or annual application) and four annual application rates (5, 10, 20, and 40 t ha(-1) year(-1)) were investigated. BDE 209 was detected in all of the sewage sludge amended soils and different parts of wheat plants collected from the contaminated soils. However, the other seven PBDE congeners (BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 154, and BDE 183) were not detected or were only observed at very low levels. A single application of sewage sludge in large quantities would likely increase accumulation of BDE 209 in soil and its subsequent uptake and translocation by wheat. The concentrations of BDE 209 in soils, wheat roots and straws increased with the increasing sewage sludge application rate. There is a negative correlation between the root accumulation factors (the ratios of concentrations in wheat roots to those in soils) and soil total organic carbon (R(2)=0.84,P<0.05), demonstrating that the bioavailability of BDE 209 was controlled by the soil total organic carbon. BDE 209 concentrations in the grains from the sewage sludge amended soils were not significantly different from those of the control soils, suggesting that atmospheric deposition was the main source of BDE 209 detected in the grains.

Aerobic transformation of BDE-47 by a Pseudomonas putida sp. strain TZ-1 isolated from PBDEs-contaminated sediment

A bacterial isolate, TZ-1, was isolated from contaminated sediment near electronic waste dismantling workshops, Taizhou, China that degraded 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47). The isolate was identified as Pseudomonas putida sp. with respect to its morphology, biochemical characteristics and 16SrDNA sequence analysis. TZ-1 can use BDE-47 as the sole carbon and energy source for growth in mineral salt medium. The isolate degraded BDE-47 up to 49.96 % of the initially applied concentration of 50 μg L(-1) after 7 days of incubation at 150 rpm, 30°C. Static conditions with pH 6.5 and temperature 30°C were considered to be optimum for BDE-47 biodegradation. Addition of co-substrates promoted cell growth, but decreased the degradation rate for BDE-47.

The presence of polychlorinated biphenyls in yellow pigment products in China with emphasis on 3,3'-dichlorobiphenyl (PCB 11)

A non-Aroclor PCB congener, 3,3'-dichlorobiphenyl (PCB 11) has recently attracted wide concerns because of its environmental ubiquity and specific sources potentially associated with yellow pigment production. In order to investigate PCB 11 and other PCBs in the yellow pigment products, 24 yellow pigment samples were collected from three different manufacturing plants in China. ∑20PCBs and PCB 11 were in the range of 50.7-9.19×10(5) ng g(-1) and 41.7-9.18×10(5) ng g(-1), respectively, which was much higher than those reported in previous study. The corresponding TEQ values ranged between 0.16 and 4.21×10(3) ng WHO2005-TEQ kg(-1). The contribution of PCB 11 to ∑20PCBs reached up to 85.5% (median value) followed by PCB 28, PCB 77, and PCB 52 with contributions of 10.5%, 6.70%, and 5.40%, respectively. Significant differences were observed for PCB 11 concentrations among the different types of yellow pigment from the same plant and among the same sample types from different plants. The PCB 11 concentrations in diarylide yellow pigments produced from 3,3'-dichlorbenzidine were the highest in all the samples. It demonstrates that yellow pigment is a significant source not only for the widespread pollution of PCB 11 but also for other PCBs, especially for the lower chlorinated congeners.

Polybrominated diphenyl ethers in farmland soils: source characterization, deposition contribution and apportionment

Polybrominated diphenyl ethers (PBDEs), a group of persistent organic pollutants (POPs), are caused for concern recently due to their adverse health effects and environmental ubiquity. In this study, atmospheric and soil PBDE levels in Taizhou, one of the largest WEEE dismantling areas in the world, were measured, ranging from 884 to 2791 pg m(-3) with an average of 1968 pg m(-3) for atmosphere and 2.96 to 200 ng g(-1)dry weight (dw) with the mean of 65.2 ng g(-1)dw for farmland soils, respectively. The close connection between soil PBDE accumulation and atmospheric deposition was also revealed by the estimation of the annual PBDE deposition flux (3.1 ± 0.9 mg m(-2)a(-1)) and the similarity between deposited congener pattern and soil congener profile. Positive matrix factorization (PMF) was conducted to extract possible sources of farmland soil PBDEs and to calculate their contributions. Based on the measured source profiles of PBDE-related activities, five sources were identified representing WEEE dumping, WEEE dismantling, WEEE open burning, residential waste dismantling, and residential waste open burning. WEEE-related recycling activities contributed primary percentage (52%) to farmland soil PBDE concentration, and open burning was an important pathway for PBDEs entering the environment.

Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ(13)C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m(-2)⋅y(-1). Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners.

Spatial distribution and inter-year variation of hexabromocyclododecane (HBCD) and tris-(2,3-dibromopropyl) isocyanurate (TBC) in farm soils at a peri-urban region

Hexabromocyclododecane (HBCD) is a high production volume brominated flame retardant (BFR) which has been of increasing environmental and public health concern due to its potential environmental persistency, bioaccumulation and toxicity. Tris-(2,3-dibromopropyl) isocyanurate (TBC) is another BFR which has recently been found in environmental matrices near a manufacturing plant, but its production volume and environmental distribution is currently not well known. This study was conducted to investigate the presence and distribution of these two BFRs in farm soils at a region in southeast Beijing. Total HBCD levels ranged from 0.17 to 34.5 ng g(-1) on a dry weight basis (dw) with a median level of 2.97 ng g(-1)dw. The composition profile of HBCD diastereoisomers was, on average, 28%, 13% and 59% for α-, β- and γ-HBCD, respectively. Detection frequency of TBC was only 25% in 2010 but was detected in all soil samples in 2011, and the median level was 0.19 ng g(-1)dw with the range between below detection limit to 1.62 ng g(-1) dw. There were no significant differences of HBCD and TBC levels among different irrigation sources in the region. The soil HBCD and TBC levels in samples collected in 2011 were significantly higher than in 2010. The increasing short-term temporal levels in farm soil might be due to the rapid urbanization in this region or could also reflect the increasing usage of HBCD and TBC after the phase out of other BFRs.

Polybrominated diphenyl ethers fate in China: a review with an emphasis on environmental contamination levels, human exposure and regulation

Because of their highly effective flame-retardant capability, polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer goods. However, compelling evidence shows that many congeners of PBDEs have been accumulating in the environment, in biota and in human populations worldwide. In China, although octabrominated diphenyl ether (octaBDE) has never been produced or used, pentabrominated diphenyl ether (pentaBDE) and decabrominated diphenyl ether (decaBDE) have been produced and used in large quantities. In the face of increasing evidence about PBDE pollution and the adoption of international conventions, there is a growing push for China to develop more stringent methods of managing PBDE waste. This paper summarizes the information about PBDE production and application, describes the flame-retarding mechanism, and then reviews the toxicity and levels of PBDEs in China's environmental media and human tissues. Based on international regulations on PBDEs, the paper finally puts forward some suggestions for Chinese policy making and for self-regulation within the flame retardant industry.

The air-water exchange of polychlorinated biphenyls and polybrominated diphenyl ethers at an urban lake, a receipt water body for the effluent from a municipal sewage treatment plant

The effluents and sludge from municipal sewage treatment plants (MSTPs) are considered as potential sources of many contaminants to the ambient environments. In the present work, the air-water exchange of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) was studied using passive air samplers at an urban lake, which receives the effluents from a MSTP in Beijing, China. The concentrations of PCBs and PBDEs in atmosphere were in the range 15.5-108 ng sample(-1) and 2.37-27.8 ng sample(-1), respectively, during the sampling period (August, 2007-July, 2008). The predominant PCBs and PBDEs were lowly halogenated congeners. The calculation for the exchange fluxes of PCBs and PBDEs using fugacity model showed that, the net exchange fluxes in different seasons were closely related to the halogen number of different congeners. Except for CBs-28 and 52, the net exchange fluxes was mainly directed from air to water for most of predominant congeners, which implied that the lower chlorinated CBs were dominated by volatilization process rather than the dry/wet depositions and diffusion between air-water interface, additionally, for heavy congeners, the dry/wet deposition process was an important source of PCBs and PBDEs in this lake.

Endocrine disruptors, polychlorinated biphenyls-induced gC1qR-dependent apoptosis in human trophoblast cell line HTR-8/SVneo

Although an association exists between exposure to polychlorinated biphenyls (PCBs) and spontaneous miscarriage, the mechanisms underlying this phenomenon remain unclear. In this study, PCBs content in plasma was detected by gas chromatography-mass spectrometry (GC-MS) and decidua tissues were examined for the expression of globular heads of C1q receptor (gC1qR) using Western blot in patients who underwent induced abortion and spontaneous abortion. Results showed increased PCBs content and gC1qR expression in patients who experienced spontaneous abortion. In vitro, Western blot analysis demonstrated significantly higher caspase 3 expression and apoptotic cell counts in green fluorescent protein (GFP)-gC1qR vector group. Additionally, gC1qR and caspase 3 showed decreased expression following PCBs plus gC1qR small interfering RNA (siRNA) treatment. The percentage of apoptotic cells increased in cells treated with PCBs alone or PCB plus negative siRNA. These data suggest that maternal exposure to PCBs is associated with adverse pregnancy outcomes and that upregulation of gC1qR is important for PCBs-mediated trophoblast cell apoptosis.

Spatial and vertical distribution of short chain chlorinated paraffins in soils from wastewater irrigated farmlands

Chlorinated paraffins (CPs) are one of the most complex groups of halogenated contaminants in the environment. However, studies of short chain CPs (SCCPs) in China are very scarce. In this study, the concentrations and distribution of SCCPs in farm soils from a wastewater irrigated area in China were investigated. SCCPs were detected in all topsoil samples, with the sum of the concentrations (ΣSCCPs) in the range of 159.9-1450 ng/g (dry weight, dw). A noticeable spatial trend and specific congener distribution were observed in the wastewater irrigated farmland. Soil vertical profiles showed that ΣSCCP concentrations below the plowed layer decreased exponentially and had a significant positive relationship (R(2) > 0.83) with total organic carbon in soil cores. Furthermore, soil vertical distributions indicated that lower chlorinated (Cl(5-6)) and shorter chain (C(10-12)) congeners are more prone to migrate to deeper soil layers compared to highly chlorinated and longer chain congeners. This work demonstrated that effluents from sewage treatment plants (STPs) could be a significant source of SCCPs to the ambient environment and wastewater irrigation can lead to higher accumulation of SCCPs in farm soils.