Polybrominated Diphenyl Ethers In Soils Research Articles

Completely recyclable and reusable automatic phase-separable catalytic system for the reductive debromination of polybrominated diphenyl ethers

An automatic phase-separable catalytic system was developed for the reductive debromination of polybrominated diphenyl ethers (PBDEs) using thiol-modified Pd nanoparticles (thiol-Pd NPs) as the catalyst, H2 as the reducing agent, and n-butanol (oil phase) and water (water phase) as solvents. This system achieved efficient and complete debromination of various PBDEs with 1–10 bromine atoms and other bromo-organic pollutants at concentrations ranging from 15 to 1500 mg L−1. Typically, this system achieved a debromination efficiency of 100 % within 15 min for all the tested bromo-organic pollutants. Importantly, the debromination reaction was conducted in a microemulsion state under stirring; upon stopping the stirring, the microemulsion automatically separated into an upper oil phase, a down water phase, and a thiol-Pd NP self-assembled membrane phase at the oil/water interface. These three phases could be easily separated from each other, allowing for their reuse across multiple debromination cycles with good reusability. The thiol modifier enhanced the stability and reusability of Pd NPs and improved the adsorption of PBDEs, facilitating their reaction with atomic hydrogen (the dominant reactive species). This method successfully eliminated PBDEs in soils by integrating with a pre-extraction process.

The Spatial Distribution and Potential Risk Assessment of POPs in Farmland around a Typical E-Waste Dismantling Site.

Pollution from electronic-waste (E-waste) dismantling is of great concern. This study investigated the concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) in 253 cropland soil samples around an abandoned E-waste dismantling site in Taizhou city, Zhejiang province in China, using an analytical method which simultaneously extracted, purified and determined the identity and quantity of the three types of persistent organic pollutants. Meanwhile, their spatial distributions, pollution characteristics, and risk assessments were further analyzed. Total PCBs in the test soils ranged from below method detection limits (ND) to 2985.25μgkg-1 on a dry weight basis (d.w.), and the spatial distribution indicated a "hot spot" of PCBs pollution in the study area. The PAHs were detected in all samples with total concentrations ranging from 4.99 to 2723.06μgkg-1d.w. The distribution of PBDEs showed the pollution characteristics of "family-run workshops", with a total content range of ND ~ 899.34μgkg-1d.w., of which BDE209 was typically the dominant congener, accounting for 74.05% of the total PBDEs content in the test soils, with the highest content reaching 857.72μgkg-1d.w. Results showed that the ecological and lifetime carcinogenic risks of PCBs and PAHs were low in the study area, but the health risk caused by oral ingestion and dermal contact accounted for the highest proportion of the total exposure risks, while inhalation could be ignored. PBDEs in soils of the study area were a potential chronic non-carcinogenic risk, particularly for children. Therefore, in order to protect human health and environment, it is necessary to regulate the management of E-waste dismantling sites and pollution control.

Prediction of adsorption capacity and biodegradability of polybrominated diphenyl ethers in soil.

Polybrominated diphenyl ethers (PBDEs) are widely used brominated flame retardants with strong toxicity concerns. Understanding the behaviors of PBDEs in soil is essential to evaluate their environmental impact. However, the limited, incoherent, and inaccurate data has challenged predicting the adsorption capacity and biodegradability of all 209 PBDE congeners in the soil. Moreover, there are minimal studies regarding the interactions between adsorption and biodegradation behaviors of PBDEs in the soil. Herein, in this study, we adopted quantitative structure-property relationship (QSAR) modeling to predict the adsorption behavior of 209 PBDE congeners by estimating their organic carbon-water partition coefficient (KOC) values. In addition, the biodegradability of commonly occurring PBDE congeners was evaluated by analyzing their affinity to extracellular enzymes responsible for biodegradation using molecular docking. The results highlight that the degree of bromination plays a significant role in both the absorption and biodegradation of PBDEs in the soil due to compound stability and molecular geometry. Our findings help to advance the knowledge on PBDE behaviors in the soil and facilitate PBDE remediation associated with a soil environment.

Effects of temperature and relative humidity on soil−air partition coefficients of organophosphate flame retardants and polybrominated diphenyl ethers

The soil−air partition coefficients (KSA) of polybrominated diphenyl ethers (PBDEs) and organophosphate flame retardants (OPFRs) is important for determining their fate in soil and air media. However, KSA values of OPFRs and PBDEs are not available from the current literature, and the effects of environmental factors such as temperature and relative humidity (RH) on KSA values are not clear. In this study, a solid-phase fugacity meter was used to measure the KSA values of PBDEs and OPFRs at different temperatures (25, 30, 35, 40, and 45 °C) and relative humidity (RH) conditions (<3 and 100% RH), the relationships between KSA and octanol−air partition coefficients (KOA) for OPFRs and PBDEs were analyzed. The results showed that an increase in temperature and RH resulted in a decrease of all KSA values for PBDEs and OPFRs. Furthermore, the effects of RH on the soil−air partitioning behavior of PBDEs were larger than that of OPFRs. In addition, a significant correlation (p < 0.0001) was observed between log KSA and log KOA. The experimental KSA values of OPFRs and PBDEs were quite different from the predicted KSA, when calculated with their KOA values. Overall, this study provides a better understanding for predicting the behavior and fate of OPFRs and PBDEs in soil−air systems.

Thermal treatment of decabrominated diphenyl ether in its highly contaminated soil in Taiwan

Polybrominated diphenyl ethers (PBDEs) were commonly used flame retardants in the world, while some of PBDEs have been listed as persistent organic pollutants (POPs). Decabrominated diphenyl ether (BDE-209) was the most commercially used PBDEs. A farm near the factory located in Northern Taiwan was highly contaminated with BDE-209. Since PBDEs in the contaminated soils can be uptake by crops shown in our previous studies and could be potentially consumed by humans, it is very important to establish a feasible treatment method for PBDE remediation in this contaminated farm. Thermal treatment of PBDEs in soil was studied. The initial concentration of BDE-209 in contaminated soil was 1.472 mg/kg. A series of thermal experiments under different operating conditions including various temperature (105, 150, 200, 250, 300, 350, 400 and 450 °C), holding time (10, 20 and 30 min), heating rate (5, 10, 20 and 40 °C/min), and soil amount (10, 100, 1000 and 2000 g) were investigated. The optimal heating conditions for thermal treatment of contaminated soil were heating at 450 °C for 30 min with a heating rate of 10 °C/min. Under this condition, the removal of BDE-209 in the different weights of contaminated soil was tested. The soils in the contaminated farm were tested to further evaluate the feasibility of remediating the on-site PBDE contaminated soil through thermal treatment, suggesting that the holding time was extended to 2 h for the field-scale contaminated soil. The results showed that BDE-209 had been removed to below the detection limit in on-site soil. This investigation is the first study using thermal treatment to remediate soils really contaminated with PBDEs.

Soil-air partitioning of semivolatile organic compounds in the Lesser Himalaya region: Influence of soil organic matter, atmospheric transport processes and secondary emissions

After decades of imposed regulations about reducing the primary emissions of persistent organic pollutants (POPs), these pollutants are still present in the environment. Soils are important repositories of such persistent semivolatile organic contaminants (SVOCs), and it is assumed that SVOCs sequestered in these reservoirs are being re-mobilized due to anthropogenic influence. In this study, concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in soil and air, their fugacities, fluxes and the soil-air partition coefficient (KSA) were determined for three different land cover types (glacial, remote/mountainous and urban) of the Lesser Himalayan Region (LHR). The concentrations of OCPs, PCBs and PBDEs in soils and air ranged between 0.01 and 2.8, 0.81–4.8, 0.089–0.75 ng g−1; 0.2–106, 0.027–182, and 0.011–7.26 pg m−3, respectively. The levels of SVOCs in the soil were correlated with soil organic matter (SOM) indicating that SOM is a substrate for the organic pollutants in soils. The Clausius-Clapeyron plots between ln P and inverse of temperature (1000/T) suggested that long range atmospheric transport was the major input source of PBDEs and higher chlorinated PCBs over the LHR. The uneven and wide distribution of local sources in LHR and up-slope enrichment of SVOCs explained the spatial variability and altitudinal patterns. The soils near mountain and urban lakes act as local sinks of SVOCs such as β-HCH, pp΄-DDT, CB-28, -118, −153, BDE-47, -99, and −154, with soil-air exchange fluxes tending more toward deposition. However, the soils near glacial lakes acted as local sources of more volatile congeners of α-HCH, γ-HCH, op′-DDT, pp′-DDE and lower to medium chlorinated PCBs such as CB-18, -28, −53, −42 and BDE-47, -99, with soil-air exchange tending more toward volatilization flux.

Fate of 4-bromodiphenyl ether (BDE3) in soil and the effects of co-existed copper

The quantitative fate of polybrominated diphenyl ethers (PBDEs) in soil is unknown. Furthermore, the effects of co-contamination by toxic copper on the behavior of PBDEs have not been investigated. Using a 14C-tracer, we studied mineralization, metabolism, and formation of non-extractable residues (NERs) of one PBDE congener, i.e., the 4-bromodiphenyl ether (BDE3) in oxic soil for 50 days, without and with amendment of Cu (400 mg kg−1 soil dw). BDE3 rapidly dissipated with a half-life of 5.5 days and large amounts of CO2 (38.8 ± 0.3% of initial applied amount at the end of incubation) and NERs (42.5 ± 0.4%) were rapidly produced. One hydroxylated metabolite (4′-HO-BDE3) was formed (8.1 ± 0.6%) at the beginning of the incubation, but then decreased to 2.2 ± 0.4%. Only BDE3 occurred in physico-chemically entrapped NERs, amounting to 9.2 ± 0.7%, while only 4′-HO-BDE3 in ester-linked NERs (10.9 ± 0.7%). The addition of Cu strongly reduced the kinetics constants of the transformations (including dissipation, mineralization, and NER-formation), the predicted maximal amounts of mineralization, as well as covalent binding of 4′-HO-BDE3 to soil. The results provide first quantitative insights into the fate of low-brominated congeners of PBDEs in soil and indicate that co-contamination by Cu may increase the environmental risks of biodegradable PBDEs in soil by increasing their persistence.

Occurrence, Distribution, Source, and Health Risk Assessment of Polybrominated Diphenyl Ethers in Surface Soil from the Shen-Fu Region, Northeast China

The Shen-Fu region is an important urban area in northeast China. We report on a study of the distribution of polybrominated diphenyl ethers (PBDEs) in representative topsoil from this region. In the summer of 2016, 72 soil samples from three cities (Shenyang, Fushun, and Shen-Fu New City) were collected, which covered four land use types:urban, rural residential, cultivated, and woodland. We report on the concentrations, compositions, and distributions of 14 PBDEs in soil and explore their sources, and additionally undertake human exposure analysis and health risk assessments. The results showed that the concentration of ∑14PBDEs in the topsoil ranged from 0.279-50.719 ng·g-1(dry weight), with a mean of (10.466±9.246) ng·g-1. The concentrations of PBDEs was ranked for the cities as:Fushun > Shenyang > Shen-Fu New City > background, and for different land use types as:urban land > rural residential land > cultivated land > forest. Deca-PBDE had the highest proportion of all congeners, accounting for 81.25%-89.23% of all PBDEs. Source analysis indicated that commercial Deca-PBDE was the main source, contributing 66.06% of the total Deca-PBDE according to principal component analysis/multiple linear regression (PCA-MLR). Among five different age groups assessed for exposure, children in Fushun had the highest exposure dose:(20.98±25.01) ng·(kg·d)-1. In terms of different land types, the highest exposure dose was for children living in urban areas:(18.54±20.27) ng·(kg·d)-1. The non-oncogenic health risks in the Shen-Fu region are of a relatively low level.

Polybrominated diphenyl ethers (PBDEs) in soil and dust from plastic production and surrounding areas in eastern of China.

Polybrominated diphenyl ethers (PBDEs) are a class of organic pollutants. They are used as flame retardants that caused worldwide environmental concern. This study investigated the occurrence of PBDEs in soils and dusts from three plastic manufacture plants and surrounding areas in Eastern China. A total of 13 PBDE congeners were detected using gas chromatography-mass spectrometer (electron impact ionization). The total concentrations of PBDEs range from 2.21 to 558, 19.7-4916, and 8.70-18,451ng/g dry weight in the soils of three sampling areas, with mean of 1004ng/gdw; in dusts, the concentrations range from 7240 to 10,469, 684-4482, and 193-3989ng/gdw, with an overall mean of 3619ng/gdw. The most abundant congener is the BDE-209, followed by BDE-153 and BDE-85. This indicates that the brominated flame retardant added in the plastic manufacture is mainly the commodity decabromodiphenyl ether. In comparison with other polluted areas around the world, the PBDE concentrations in the soils of the plastic manufacture plants are similar to those in soils of waste plastic disposal areas and PBDEs production sites, but orders of magnitude higher than those in agricultural soils, mountain soils and rural soils. Daily exposure was estimated using the average concentrations of the pollution sites. The hazard quotient shows that the PBDEs pose considerable human health risks, especially to children, to which attention should be paid.

Relationships between the bioavailability of polybrominated diphenyl ethers in soils measured with female C57BL/6 mice and the bioaccessibility determined using five in vitro methods

Several in vitro methods for simulating human gastrointestinal digestion have been validated for predicting the bioavailability of heavy metals, but the methods for successfully predicting the bioavailability of organic pollutants are still limited. In this study, we used an adapted fasting in vitro digestion method (Fa-VDM) from the Simulator of the Human Intestinal Microbial Ecosystem and four other in vitro methods comprising In Vitro Gastrointestinal, a physiologically-based extraction test, the unified BARGE method, and Deutsches Institut für Normung e.V. in order to measure the bioaccessibility of polybrominated diphenyl ethers (PBDEs) in soils from an e-waste dismantling town, China, with a Standard Reference Material (SRM2585) as the control. Furthermore, the bioaccessibility data were compared with the bioavailability measured using female C57BL/6 mice. The bioavailability of PBDEs in the soils and SRM2585 were 1.7% to 38.1% and 3.9% to 48.8%, respectively, and the bioaccessibility determined using Fa-VDM were 1.6–55.4% and 6.7–32.1%. There were negative and parabolic correlations between octanol/water partition coefficient for PBDEs and the bioavailability and bioaccessibility, respectively, whereas the H/C ratios and organic matter contents of the soils did not correlate with them. The bioaccessibility data determined by Fa-VDM were generally higher than those obtained using the other four methods, mainly due to the higher bile concentration and larger liquid to solid ratio in the digestion solution in Fa-VDM. There was a significant linear relationship between the results according to the in vivo and in vitro method of Fa-VDM where the slopes varied from 0.83 to 1.16 (R2 > 0.73) and intercepts from 0.3%–7.7% for BDE47, 99, 100, and 153 measured using Fa-VDM, thereby indicating that the bioaccessibility assessed by this method can potentially be used to predict the bioavailability of moderately brominated congeners in soils.

Occurrence and distribution of polybrominated diphenyl ethers in soils from an e-waste recycling area in northern China

Polybrominated diphenyl ethers (PBDEs) are widespread persistent organic pollutants (POPs) because of their extensive use in diverse electronic products, which have posed great threats to human health and ecosystem. In this study, a total of 54 soil samples were collected from an e-waste recycling area in Tianjin, northern China for analyzing the occurrence and distribution of 14 PBDE congeners. The concentrations of BDE 209, ∑13PBDEs and ∑14PBDEs in the soils from Ziya e-waste recycling area were 2.9–2666 ng/g dw (dry weight) (average 90 ng/g dw), 3.0–41 ng/g dw (average 13 ng/g dw) and 5.9–2699 ng/g dw (average 103 ng/g dw), respectively. The ∑14PBDEs concentration showed a dramatic decrease from the central area to the surrounding area. Generally, PBDEs in the northern part showed higher levels than the southern part of the e-waste recycling area due to the wind direction in Tianjin. Deep soil was less polluted by PBDEs, which largely comes from the deposition, migration and infiltration of PBDEs in the surface soils. Overall, PBDEs level in the studied area was much lower than some typical e-waste recycling areas in south China, such as Guiyu and Qingyuan, but significantly higher than the non-e-waste recycling areas. BDE 209, BDE 138 and BDE 28 were the three dominant PBDE congeners in the soil. Principal component analysis (PCA) indicated that the commercial penta-BDEs and deca-BDE could be considered as the main sources of PBDEs pollution in this region. Redundancy analysis (RDA) suggested that the local PBDEs sources rather than soil properties influenced the PBDEs distribution in Ziya e-waste recycling area. This study systematically revealed the occurrence and distribution of PBDEs in soils from the biggest established circular economy park in northern China.

Application potential of dummy molecularly imprinted polymers as solid-phase extraction sorbents for determination of low-mass polybrominated diphenyl ethers in soil and sediment samples

Despite the introduction of restrictive regulations in the USA and the European Union, polybrominated diphenyl ethers (PBDEs) are still found in various types of environmental and biological samples at significant concentration levels. The presence of these persistent organic pollutants in the environment raises important issues because of their negative impact on immunological and neurological systems, and on the hormonal balances in living organisms. From the analytical point of view, the final determination of PBDEs would entail substantial challenges, because it would necessitate conducting the pre-concentration of analytes, or sample clean up. The aim of the present study is to demonstrate the analytical application potential of developed dummy molecularly imprinted polymers as solid-phase extraction sorbents for the selective recognition of low-mass PBDEs. The 4,4′-dihydroxydiphenyl ether was employed as a dummy template of low-mass PBDEs. The developed types of the sorption materials were used in the sample preparation stage of the analytical procedure to determine the PBDE-47 and PBDE-99 levels in selected representatives of environmental samples—reference materials of soil and bottom sediments. The recovery values of PBDE-47 and PBDE-99 from the studied solid samples ranged from 60% to 87%, depending on the applied DMIPs type.

Spatio-temporal variations of atmospheric and soil polybrominated diphenyl ethers (PBDEs) in highly industrialized region of Dilovasi

Polybrominated diphenyl ethers (PBDEs) were investigated in ambient air of a highly industrialized region at 23 different sampling sites for 12 months. Total concentrations of 8 PBDE congeners (Σ8PBDE) were found to be between 5.73 and 520 pg m−3 (94.7 ± 78.9; average ± SD) and BDE-209 was the predominant congener, followed by BDE-47 and/or BDE-99. Their contributions to Σ8PBDE were 71 ± 13, 9 ± 4% and 8 ± 4%; respectively. Compared to previous studies around the world, high concentrations detected in Dilovasi demonstrated the severity of atmospheric PBDE pollution in the area. For all sampling sites, average PBDE concentration obtained in summer (118.5 ± 98.7 pg m−3) was higher than one found in winter period (79.7 ± 59.1 pg m−3) and this seasonal difference was more obvious in industrial/urban sites (p < 0.05), probably due to enhanced volatilization from ongoing PBDE sources such as waste incineration and iron-steel plants. The soil-air exchange tendencies of PBDEs did not show substantial differences between the sampling periods with small variations for each congener. All congeners either tend to deposit to soil or to be within the equilibrium range for all seasons. This reflects the impact of local ongoing sources rather than temperature on the direction of soil-air exchange of PBDEs in this region. Specific congener ratios such as BDE-47/-99 and -99/-100 confirmed the impact of local sources rather than long-range transport on PBDE congeners in the study area. According to the Positive Matrix Factorization (PMF) results, the BDE-209 content of the first factor was found to be 91.7% and this factor was attributed to the deca-BDE technical formulations. The second factor was highly rich with both BDE-183 (%61) and BDE-28 (%52) and identified as octa-BDE technical products. The last factor was highly loaded with BDE-99, BDE-47, BDE-100, BDE-154 and BDE-153 and has been determined as the penta-BDE commercial formulations.

A Comparison of Concentrations and Congener Patterns of Polybrominated Diphenyl Ethers in Seasonally Sampled Outdoor Air from a Farmland Area in Guangzhou, South China.

To investigate the concentration and congener patterns of polybrominated diphenyl ethers (PBDE) in outdoor air from farmland area, air samples were collected using passive and active sample methods from April to November 2012, in an e-waste dismantling town in the Guangzhou region of South China. The sum of gaseous and particulate PBDE concentrations averaged 74.26pg/m3 and ranged between 3.24 and 247.30pg/m3, while the mean gaseous and particulate PBDEs were 19.20 and 55.07pg/m3, respectively. The PBDE level was comparable to those in urban air of non-electric waste areas, but much lower than those in both indoor and outdoor air of e-waste dismantling workshop area. Dominant congeners were BDE-47 and BDE-28 for the gaseous phase and BDE-209 and BDE-99 for the particulate phase. Relationship analysis showed that soil PBDEs were more significantly correlated with passive samples than with active samples, indicating that passive sample pattern could capture the accumulative effect of the sampling period and better represent the extent of soil contamination.

Occurrence and distribution characteristics of polybrominated diphenyl ethers (PBDEs) from a closed deca-BDE manufacturing factory in Jiangsu province, China

Concentrations and distributions of polybrominated diphenyl ethers (PBDEs) were investigated in soils and plants from a closed deca-BDE manufacturing factory to evaluate and discuss their pollution level and distribution characteristics. Eight PBDEs were analyzed in this study. The eight native PBDEs and 13C12-PCB209 (internal standard) were bought from Accustandard Inc. The eight 13C12-labeled PBDEs (isotope internal standard) were obtained from the Cambridge Isotope Laboratories, Inc. Soxhlet was chosen as the sample extraction method. The majority of lipid and pigment were removed by adding concentrated H2SO4 to each extract. Then, the concentrated extracts were further cleaned by multilayer silica gel columns. Finally, the eluants were concentrated to 1 mL. An internal standard was added to the final extract prior to the instrumental analysis. Extracts were determined by gas chromatography coupled to mass spectrometry in electron impact mode with DB-1 column. Concentrations of PBDEs ranged from N.D. to 3.7 × 104 ng g−1 dry weight (dw) with the median concentrations from 0.60 to 1.17 × 104 ng g−1 dw. BDE-209 was the dominant congener in soils. The concentrations of PBDEs in different functional areas followed the order: manufacturing workshop (MW) → warehouse (WH) → administration area (AD). The levels of PBDEs were shown a decreasing tendency with the increase of the soil depth. However, different trends were observed between low-brominated BDE and high-brominated BDE. In plant samples, concentrations of ∑7 PBDEs (BDE-28, -47, -100, -99, -154, -153, -183) ranged from 7.89 to 1087.19 ng g−1 dw, and the concentrations of BDE-209 ranged from 2805.6 to 19,382.9 ng g−1 dw. The pollution level of PBDEs in the closed deca-BDE factory was lower than PBDEs of manufacturing factory, but higher than PBDEs of e-waste site and much higher than PBDEs of urban sites. The environmental risk caused by the residual of PBDE is of concern. This is the first research to study the pollution of PBDEs in soils and plants from a closed deca-BDE factory.

Occurrence and Source Effect of Novel Brominated Flame Retardants (NBFRs) in Soils from Five Asian Countries and Their Relationship with PBDEs.

This paper presents the first comprehensive survey of 19 novel brominated flame retardants (NBFRs) in soil samples collected among five Asian countries. High variability in concentrations of all NBFRs was found in soils with the geometric mean (GM) values ranging from 0.50 ng/g dry weight (dw) in Vietnam to 540 ng/g dw in the vicinity of a BFR manufacturer in China. In urban, rural, and background locations, the GM concentrations of ∑19NBFRs decreased in the order of Japan > South Korea > China > India > Vietnam. Correlations among different NBFR compounds were positive and statistically significant (p < 0.05), suggesting that they originate from similar sources. Evidence for simultaneous application between polybrominated diphenyl ethers (PBDEs) and NBFRs were also noted. Principal component analysis of NBFR concentrations revealed specific pollution sources for different NBFRs coming from urban, BFR-related industrial, and e-waste sites. For the first time, this study demonstrates a "point source fractionation effect" for NBFRs and PBDEs. The concentrations of all NBFRs and PBDEs were negatively and significantly correlated with the distance from BFR-related industrial and e-waste regions. Positive and significant correlation between population density and NBFR concentrations in soils was identified. Our study revealed that the primary sources effects were stronger than the secondary sources effects in controlling the levels and distribution of NBFRs and PBDEs in soils in these five Asian countries.

Bioaccumulation of PBDEs and PCBs in a small food chain at electronic waste recycling sites

ABSTRACTSoil, rice plant, and animal samples were collected from an e-waste recycling area to investigate the levels and bioaccumulation extent of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) released from e-waste that was processed using crude recycling methods in Changzhou, China. ∑PBDE and ∑PCBs levels of soils were significantly higher at the e-waste dismantling areas than those from residential areas. PBDEs in soils resulted in their increasing accumulation in rice plants. Median values of ∑PCBs in the sampling species were 120–12120 ng/g wet weigh (ww), and the Cplant/Csoil values for BDE-28 and PCB-28 were one order of magnitude greater than those for BDE-209 and PCB-180, respectively. Moreover, distributions of PBDE and PCB congeners in rice plants were very similar, even among different sampling sites. ∑PBDEs and ∑PCBs had the highest BMF values at the investigated sites. Therefore, in addition to commercial PBDEs and PCBs, their debromination products should be another concern in assessing the adverse influences of PBDEs and PCBs on the environment and human health.

Polybrominated Diphenyl Ethers (PBDEs) in Surface Soils across Five Asian Countries: Levels, Spatial Distribution, and Source Contribution.

A total of 23 polybrominated diphenyl ether (PBDE) congeners were measured in soil samples collected in areas with no known point source [urban/rural/background (U/R/B) sites] and in areas with known point source [brominated flame retardant (BFR)-related industrial sites (F sites) and e-waste recycling sites (E sites)] across five Asian countries. The highest PBDE concentrations were found in BFR-related industrial and e-waste recycling sites. The concentrations of PBDEs in U/R/B sites decreased in the following order: urban > rural > background sites. Total PBDE concentrations were dominated by BDE-209, while BDE-17, -85, -138, -191, -204, and -205 were the least abundant compounds. In both urban sites and rural sites, the mean concentrations of total PBDEs (∑23BDEs) in soils decreased in the following order: Japan > China > South Korea > India > Vietnam. The concentrations of PBDEs in soils were comparable with those reported in other studies. Among the three commercial PBDE mixtures, relatively large contributions of commercial penta-BDE were observed in Vietnam, whereas deca-BDE was the dominant form in mixtures contributing from 55.8 ± 2.5 to 100.0 ± 1.2% of the total PBDEs in soils collected from other four countries. Regression analysis suggested that local population density (PD) is a good indicator of PBDEs in soils of each country. Significant and positive correlation between soil organic content and PBDE level was observed in Chinese soil for most nondeca-BDE homologues with their usage stopped 10 years ago, indicating its important role in controlling the revolatilization of PBDEs from soil and changing the spatial trend of PBDE in soil from the primary distribution pattern to the secondary distribution pattern, especially when primary emission is ceased.

A Purification Method for 10 Polybrominated Diphenyl Ethers in Soil Using Accelerated Solvent Extraction-Solid Phase Extraction

Abstract An optimized method was established for the determination of 10 polybrominated diphenyl ethers (PBDEs) in soil using gas chromatography coupled with electron capture detector (GC-ECD). Accelerated solvent extraction (ASE) was used to extract 10 PBDEs from soil and a comparative study on 4 kinds of extraction systems ( i -hexane, i -hexane-acetone (4:1, V/V ) n -hexane-acetone (1:1, V/V ), n -hexane-dichloromethane (1:1, V/V )) was conducted to obtain an optimal extraction effect of PBDEs. The purification of 10 PBDEs in soil solution was completed by solid phase extraction (SPE). Ten kinds of SPE columns with different filters were applied to the purification process. The optimized conditions were acquired using the extraction system of n -hexane-acetone (4:1, V/V ) and purification with acid silica gel column. Under the optimized conditions, the average recoveries of 10 PBDEs in soil ranged from 85.4% to 103.1% with the RSDs of 1.7%–4.6%. Method detection limits (MDLs) were 0.04–0.22 ng mL −1 . The method was simple, rapid and efficient, and quite feasible for the determination of the 10 PBDEs in contaminated soil.

A novel technology for remediation of PBDEs contaminated soils using tourmaline-catalyzed Fenton-like oxidation combined with P. chrysosporium

We carried out the 70-day remediation process for soil contaminated polybrominated diphenyl ethers (PBDEs) using a novel technology, a tourmaline catalyzed Fenton-like reaction (TCFR) combined with Phanerochaete chrysosporium (TCFR+P) in field soil microcosms. The results showed that the TCFR is more efficient in removing PBDE compounds with lower numbers of bromine (Br) atoms such as BDE-28, BDE-47, BDE-99, BDE-100, while the TCFR+P is a good method to remove the PBDEs with greater number of Br atoms. For the total PBDE removal from soil, the TCFR was more efficient than that in the soil added TCFR+P. SEM analysis showed that lower PBDE removal using TCFR+P may be due to the mycelium produced by P. chrysosporium covering the humin (HM) surface, thereby decreasing the effective contact between hydroxyl radicals (OH) and PBDEs. Moreover, a systemic series of experiments on the effects of the TCFR and TCFR+P on soil pH, soil organic matter (SOM) content, humic acid (HA) and HM compositions and structure, soil fungi, and degradation pathways were designed to discuss the removal mechanisms of the TCFR and the TCFR+P. Both of the TCFR and the TCFR+P caused a decrease in the SOM contents, a decline in aromaticity, an increase in surface hydrophilicity, an improvement in the polarity index of HA and HM, and an unexpected increased ergosterol content, compared to that of the soil added H2O2, tourmaline or P. chrysosporium alone, which in turn, enhanced the removal of PBDEs. Additionally, the five and nine oxidation degradation products of BDE-47, -153, respectively, were analyzed by LC–MS/MS. To the best of our knowledge, this study is the first report demonstrating that PBDEs in soil can be removed through TCFR oxidization.