Tri-decabrominated diphenyl ethers and hexabromocyclododecane in indoor air and dust from Stockholm microenvironments 2: indoor sources and human exposure

Data on polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) concentrations from Stockholm, Sweden, indoor microenvironments were combined with information from detailed questionnaires regarding the sampling location characteristics, including furnishing and equipment present. These were used to elucidate relationships between possible flame-retarded sources and the contaminant concentrations found in air and dust. Median concentration ranges of ΣPenta-, ΣOcta-, ΣDecaBDE and HBCD from all microenvironments were 19-570, 1.7-280, 29-3200 and < 1.6-2 pg/m³ in air and 22-240, 6.1-80, 330-1400 and 45-340 ng/g in dust, respectively. Significant correlations were found between concentrations of some PBDEs and HBCD in air and/or dust and the presence of electronic/electrical devices, foam furniture, PUF mattresses and synthetic bed pillows in, as well as floor area and construction year of the microenvironment. Car interiors were a source to indoor air in dealership halls. Using median and maximum concentrations of ΣPenta-, ΣOcta-, ΣDecaBDE and HBCD in air and dust, adult and toddler (12-24 months) intakes from inhalation and dust ingestion were estimated. Toddlers had higher estimated intakes of ΣPenta-, ΣDecaBDE and HBCD (7.8, 43, 7.6 ng/d, respectively) from dust ingestion than adults (5.8, 38, 6.0 ng/d, respectively). Air inhalation in offices was also an important exposure pathway for ΣPenta-, ΣOcta- and ΣDecaBDE in adults. For ΣPentaBDE and HBCD, air inhalation and dust ingestion play minor roles when compared to previously published Swedish dietary intakes (median exposures). However, in worst case scenarios using maximum concentrations, dust ingestion may represent 77 and 95% of toddler intake for ΣPentaBDE and HBCD, respectively.     

光源和溶剂对十溴联苯醚光降解的影响

研究了不同光源和溶剂对十溴联苯醚(DecaBDE)光降解特性的影响,并对其降解产物进行了探讨.结果表明,在所试光源和溶剂条件下,DecaBDE均有一定程度的光降解,且都近似符合一级降解动力学.同一光源下,不同溶剂对DecaBDE降解表现出不同的影响.在太阳光照射下,DecaBDE降解速率为甲苯>甲醇>正己烷>正己烷/丙酮>甲醇/水>乙醇/水;在模拟光源照射下,DecaBDE降解速率为甲苯>甲醇>甲醇/水>乙醇/水>正己烷>正己烷/丙酮;在紫外光照射下,DecaBDE降解速率为甲苯>甲醇>正己烷/丙酮>正己烷>甲醇/水>乙醇/水.同一溶剂中,DecaBDE降解速率均为紫外光>太阳光>模拟光源.尽管光源和溶剂对DecaBDE降解速率产生了一定影响,但降解途径基本一致,均为DecaBDE经光解脱溴产生低溴联苯醚.     

Abstracts to forthcoming papers

Soil and sediments collected at a former chlor‐alkali plant in coastal Georgia (United States), revealed the presence of PCDF concentrations as great as 82.3 ng/g, dry wt. PCDF congener profile in soil was typical of “chlorine pattern”; with elevated proportions of OCDF and HpCDF. Concentrations of PCDFs declined gradually by 44‐fold at a distance of about 500 m along the contamination gradient. Of PCDDs/DFs, 2,3,7,8‐substituted PCDFs accounted for 94–98% of the TCDD‐like activity, which declined by 25‐fold, corresponding with the reduction of total PCDF concentrations. Concentrations of PCDDs in sediments were as great as 17 ng/g, with an elevated contribution from OCDD. The magnitude of decline in PCDD concentrations with distance from the source was less pronounced than that for PCDFs. PBDDs and PBDFs were not detected. Polybrominated biphenyl ether (PBBE) and monobromo‐heptachloro dibenzo‐p‐dioxins and dibenzofurans (PXDDs/DFs) were found, though, at low concentrations. Their spatial distribution was similar to those of PCDDs.     

颗粒活性炭吸附工艺对水体中甲基叔丁基醚的去除

通过批式平衡实验考察了各种材质活性炭对MTBE的最大吸附容量以及吸附的影响因素.结果表明各活性炭的吸附能力依次为JHBG1>JHBG2>GCN8303F300>YK>Bamboo,其中2种国产竹炭JHBG1和JHBG2对低浓度污染的地下水处理时的理论耗炭量分别为0.14和0.18g/L;水体中天然有机物对MTBE有一定的竞争吸附,丹宁酸值较大的活性炭比较有利于地下水中MTBE的去除.采用连续流的微型快速穿透实验(MCRB)考察了活性炭的吸附容量利用率,结果证明活性炭吸附可以作为一种有效的地下水中MTBE的去除工艺,这为MTBE污染场地的异位修复提供一个实际可行的参考.     

Photocatalytic debromination of preloaded decabromodiphenyl ether on the TiO(2) surface in aqueous system

There have been serious concerns about polybromodiphenyl ethers (PBDEs) in the environment because of their global distribution and bioaccumulation. Owing to strong hydrophobicity of PBDEs, the regular photocatalytic system, in which the substrate is solvated in the bulk solution, is not applicable to the removal of the PBDEs in water. In this work, the photocatalytic reduction degradation of decabromodiphenyl ether (BDE209), the most-used PBDEs, was investigated in aqueous system, by pre-adsorbing it on the surface of photocatalyst. It was found that the preloaded BDE209 underwent efficient reductive debromination in aqueous system under irradiation with wavelength larger than 360 nm in the presence of electron donors such as methanol. Our experiments further show that such a preloaded system exhibits different characteristics from that in the organic solution. The meta-debrominated intermediate is predominant in the present system, while the ortho-debrominated one is the main nona-BDE products in the organic solution. In addition, different from other photocatalytic system, the pH has little effect on the photocatalytic reaction. We propose that these differences are originated from the formation of overlayer of hydrophobic BDE209 to limit the motion of BDE209 and the access of water and H⁺/OH⁻ to the TiO₂ surface.     

Polybrominated diphenyl ethers in food and associated human daily intake assessment considering bioaccessibility measured by simulated gastrointestinal digestion

The concentrations of PBDEs in 299 vegetable and animal-based food samples of 31 species, collected in Shanghai, China, and the bioaccessibility of PBDEs in part of the samples were determined. The PBDE concentrations ranged from 0 to 1245.4 pg g⁻¹ with animal-based food containing more PBDEs than vegetables. The bioaccessibility of PBDEs, determined by a method simulating human gastrointestinal digestion process, were from 2.6% to 39.9% in vegetables, and from 5.2% to 105.3% in animal-based food. For animal-based food, good correlations were observed between the bioaccessibility of PBDEs and the fat content, thus the fat content in animal-based food was able to be used to estimate the bioaccessibility of PBDEs. The total daily intake of PBDEs via ingestion of vegetables and animal-based food for an average Shanghai resident was estimated as 13 235.7 and 13 668.0 pg d⁻¹, respectively, but the amounts available for human absorption were reduced to 2674.4 and 4316.6 pg d⁻¹ after the PBDE bioaccessibility was considered. Finally, the contributions of different food groups to the total daily intake of PBDEs were evaluated. The results revealed that, when not considering the bioaccessibility of PBDEs, vegetables were the leading contributor (49.2%), followed by fish (34.0%). However, the sequence was reversed after the PBDE bioaccessibility was taken into account. The results indicated that human exposure to PBDEs via food ingestion might have been significantly overestimated and the exposure assessment could be misleading if the bioaccessibility of PBDEs was not considered.     

Human maternal and umbilical cord blood concentrations of polybrominated diphenyl ethers

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants in commercial products, have become ubiquitous environmental contaminants. Although adult human exposure to PBDEs is well documented, developmental exposure is less well characterized. The objectives of this study were to measure maternal and fetal exposure to nine PBDE congeners and to investigate potential associations with birth weight. PBDE congeners were quantified in maternal serum at 24-28 weeks of pregnancy, delivery, and umbilical cord serum (UCS) by gas chromatography-mass spectrometry (GC/MS/MS). Complete blood sample sets were obtained from 97 pregnant women (mean age 33.1 ± 0.5 years). PBDE-28, -47 and -99 were quantified in all samples tested and PBDE-47 was the most abundant congener measured in both maternal (mid-pregnancy and delivery samples geometric mean = 26.9 and 26.9, respectively) and UCS (GM = 56.0 ng g⁻¹ lipid). The UCS concentration for all congeners with the exception of PBDE-153 was higher vs. maternal delivery samples (p < 0.001). Only the UCS concentration of PBDE-17 and -99 were significantly associated (β = −49.860, p = 0.032, and β = −3.645, p = 0.05) with birth weight. However, after adjustment for potential confounders only the association between PBDE-99 and birth weight remained significant (β = −3.951 and p = 0.016). We conclude that: the fetus is exposed to PBDEs from at least the second trimester of pregnancy onward; PBDE congeners are higher in UCS compared to maternal serum samples collected at delivery; and that developmental PBDE exposure is potentially associated with lower birth weight.     

Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants in air and seawater of the European Arctic

The spatial distribution of polybrominated diphenyl ethers (PBDEs) and several alternative non-PBDE, non-regulated brominated flame retardants (BFRs) in air and seawater and the air-seawater exchange was investigated in East Greenland Sea using high-volume air and water samples. Total PBDE concentrations (Ó₁₀PBDEs) ranged from 0.09 to 1.8 pg m⁻³ in the atmosphere and from 0.03 to 0.64 pg L⁻¹ in seawater. Two alternative BFRs, Hexabromobenzene (HBB) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), showed similar concentrations and spatial trends as PBDEs. The air-seawater gas exchange was dominated by deposition with fluxes up to −492 and −1044 pg m⁻² day⁻¹ for BDE-47 and DPTE, respectively. This study shows the first occurrence of HBB, DPTE and other alternative flame retardants (e.g., pentabromotoluene (PBT)) in the Arctic atmosphere and seawater indicating that they have a similar long-range atmospheric transport potential (LRAT) as the banned PBDEs.     

全氟异丁烯的综合利用

全氟异丁烯是热解法生产四氟乙烯与六氟丙烯的剧毒副产物,通常焚烧销毁。其综合利用途径是用甲醇处理得到八氟异丁基甲基醚,八氟异丁基甲基醚可以转化为六氟丙酮、1,1,1,3,3,3－六氟丙烷、1,1,1,3,3－五氟丙烯、九氟异丁基醚、α-（三氟甲基）芳基乙酸等有用含氟产品。     

TiO2催化超声降解月桂醇聚氧乙烯(9)醚溶液

表面活性剂随废水、废物的排放进入水体或土壤等环境,会对环境造成严重的污染.因此,有必要在其排放之前采用既安全可靠又有效的方法对其进行处理.本文采用经过600℃高温处理的锐钛矿型TiO2作为催化剂,以超声催化降解月桂醇聚氧乙烯(9)醚(AEO9)反应为模型,研究各种因素对TiO2催化超声降解的影响.结果表明,在TiO2催化剂作用下超声降解AEO9是可行的,且效果明显.在超声波功率为600 W,经600℃活化的TiO2催化剂用量为0.5～0.7g/L,AEO9水溶液初始质量浓度为60 mg/L,初始pH值为4.0的条件下,降解2 h后,AEO9降解率可达99%以上.