Per- and polyfluorinated compounds (PFCs) in house dust and indoor air in Catalonia, Spain: implications for human exposure

A total of 27 per- and polyfluorinated compounds (PFCs) were determined in both house dust (n = 10) and indoor air (n = 10) from selected homes in Catalonia, Spain. Concentrations were found to be similar or lower than those previously reported for household microenvironments in other countries. Ten PFCs were detected in all house dust samples. The highest mean concentrations corresponded to perfluorodecanoic acid (PFDA) and perfluorononanoic acid (PFNA), 10.7 ng/g (median: 1.5 ng/g) and 10.4 ng/g (median: 5.4 ng/g), respectively, while the 8:2 fluorotelomer alcohol (FTOH) was the dominating neutral PFC at a concentration of 0.41 ng/g (median: 0.35 ng/g). The indoor air was dominated by the FTOHs, especially the 8:2 FTOH at a mean (median) concentration of 51 pg/m³ (median: 42 pg/m³). A limited number of ionic PFCs were also detected in the indoor air samples. Daily intakes of PFCs were estimated for average and worst case scenarios of human exposure from indoor sources. For toddlers, this resulted in average intakes of ∑ ionic PFCs of 4.9 ng/day (0.33 ng/kg_bw/day for a 15 kg toddlers) and ∑ neutral PFCs of 0.072 ng/day (0.005 ng/kg_bw/day) from house dust. For adults, the average daily intakes of dust were 3.6 and 0.053 ng/day (0.05 and 0.001 ng/kg_bw/day for a 70 kg adult) for ∑ ionic and ∑ neutral PFCs, respectively. The average daily inhalation of ∑ neutral PFCs was estimated to be 0.9 and 1.3 ng/day (0.06 and 0.02 ng/kg_bw/day) for toddlers and adults, respectively. For PFOS, the main ionic PFC detected in indoor air samples, the median intakes (based on those samples where PFOS was detected), resulted in indoor exposures of 0.06 and 0.11 ng/day (0.004 and 0.002 ng/kg_bw/day) for toddlers and adults, respectively. Based on previous studies on dietary intake and drinking water consumption, both house dust and indoor air contribute significantly less to PFC exposure within this population.     

Importance of greater interdisciplinarity and geographic scope when tackling the driving forces behind biological invasions

Invasive non-native species are important drivers of ecosystem change, yet the driving forces of biological invasions themselves are poorly understood. Such information is essential to ensure policies focus on the most relevant drivers, and that future scenarios capture the full range of potential outcomes for invasive non-native species. I carried out a bibliometric analysis of articles published from 2000 to 2020 that address either invasive non-native species or biodiversity and ecosystem services and that also mention 1 or more drivers of ecosystem change. I examined 5 indirect drivers (demographic, economic, governance, sociocultural, and technological) and 6 direct drivers (climate change, invasive non-native species, land-use or sea-use change, natural hazards, pollution, and resource extraction). Using the Web of Science core collection of citation indexes, I undertook searches of article titles and keywords and retrieved 27,462 articles addressing invasive non-native species and 110,087 articles dealing with biodiversity or ecosystem services. Most research to date on biological invasions as well as on biodiversity and ecosystem services has focused on anthropogenic direct drivers of ecosystem change rather than indirect drivers. Yet currently, less than 18% of articles addressing biological invasions examined drivers of ecosystem change, a similar level to that found over 20 years ago for biodiversity or ecosystem services. Knowledge of the drivers of biological invasions is limited, emphasizes tractable drivers over those that require an interdisciplinary approach, and is biased toward developed economies. Drivers generally deemed important for biological invasions, such as governance and resource extraction, accounted for less than 2% of research effort. The absence of a systematic understanding of the forces that drive invasive non-native species and how they interact means that attempts to mitigate or forecast biological invasions are likely to fail. To address biological invasions requires a much better orientation of national and international research on drivers in relation to both their actual importance as well as their policy relevance.     

VOCs污染场地挖掘过程的环境健康风险评价

开展了在典型污染场地修复过程中VOCs散逸浓度检测实验,并且建立了3条暴露途径对修复过程进行健康风险评价.结果表明,单污染物多途径累计非致癌指数最高的是四氯化碳,高达8.86E+01,其对综合非致癌影响贡献率为74.45%.多污染物质同一暴露途径危害指数最高的是呼吸暴露途径:1.01E+02,占综合危害指数的84.87%,非致癌综合危害指数为1.19E+02.单污染物多途径累计致癌指数最高的是1,2-二氯乙烷:3.08E-02,其对综合致癌影响贡献率为69.53%.多污染物质同一暴露途径危害指数最高的是呼吸暴露途径:3.96E-02,占综合致癌指数的89.39%,总致癌危害指数达到4.43E-02.     

冬小麦田O3气孔与非气孔沉降及风险评估

为了深入了解农田生态系统的O_3干沉降过程,并基于O_3通量(尤其是气孔O_3累积通量)指标进行风险评估,利用涡度相关系统对冬小麦田的O_3干沉降过程进行了连续动态观测,初步分析O_3浓度和总O_3通量的变化过程,着重探析气孔O_3沉降和非气孔O_3沉降的变化特征及其与主要气象因子的关系,并基于剂量指标(AOT40)和通量指标(DF_s06)分别推算出冬小麦的产量损失率.结果表明,观测期间(自2016年3月16日至5月30日)日平均O_3浓度(cO_3)为32.9 n L·L-1;白天(08:00~18:00)和夜间平均总O_3通量(F_(O3))分别为-7.6 nmol·(m~2·s)~(-1)和-3.1 nmol·(m~2·s)~(-1),日均F_(O3)为-5.1nmol·(m~2·s)~(-1).逐日平均气孔O_3通量(F_s)的变化范围为0~-5.1 nmol·(m~2·s)~(-1),日均F_s为-1.43 nmol·(m~2·s)~(-1).逐日平均非气孔O_3通量(F_(ns))的变化范围为-1.43~-10.31 nmol·(m~2·s)~(-1),日均F_(ns)为-3.66 nmol·(m~2·s)~(-1).较强的太阳辐射(SR)、较高的温度(T)和适度湿润的条件有利于冬小麦气孔沉降;较强的SR、适度的T和湿润条件是有利于冬小麦非气孔沉降.在整个观测期间,总O_3累积吸收通量(DF_(O3))、气孔O_3累积吸收通量(DF_s)和非气孔O_3累积吸收通量(DF_(ns))分别为31.58、9.99和21.59 mmol·m~(-2),总DF_s和总DF_(ns)分别占总DF_(O3)的32%和68%.通过剂量指标AOT40和通量指标DF_s06响应方程计算出的冬小麦产量损失率分别为11.58%~20.37%和20%~23.56%.     

长距离污染传输对珠江三角洲区域空气质量影响的数值模拟研究

采用CMAQ模型系统对珠江三角洲(以下简称珠三角)区域2006年主要大气污染物浓度进行模拟,获得该区域主要污染物浓度时空分布和大气传输季节变化特征,并结合其它相关研究方法分析长距离传输对珠三角区域空气质量的影响.模型模拟结果揭示了珠三角NO2、SO2、PM10、PM2.5浓度具有秋冬季高、春夏季低的季节变化特征,而珠三角O3浓度的高值出现在秋季.零排放扰动法表明长距离传输对珠三角15个区域监测子站NO2、SO2、PM10和PM2.5浓度平均贡献分别为2.6%、13.9%、24.2%和28.1%,并且秋冬季长距离传输贡献大于春夏季.反向轨迹聚类方法显示珠三角区域代表性站点万顷沙72 h反向控制气团依据其来向可分为沿岸气团、大陆气团、区域环流和海洋气团.万顷沙站点主要污染物小时观测浓度大于150μg·m-3的时段与短距离沿岸气团、短距离大陆气团以及区域环流主导下的污染物传输密切相关.四维传输通量分析结果证实,NO2污染传输通道无法由广东省外延伸至珠三角地区,因此珠三角大气NO2浓度主要来源于广东省内的排放.珠三角在受沿岸气团或大陆气团控制时存在从福建省或江西省一直延伸至珠三角的SO2和PM2.5高通量污染传输通道.因此控制珠三角区域大气污染需考虑区域背景气象条件差异,针对不同污染物采取不同的区域联防联控措施.     

Transformations in carbon and nitrogen-forms in peat subjected to progressive thermal stress as revealed by analytical pyrolysis

To study the characteristic N-forms of humic-type materials, samples of sapric peat from Galicia (northern Spain) were heated at 350 °C for 60, 90, 120, 150 and 180 s, and studied by Curie-point Py-GC/MS, solid-state CPMAS ¹³C-NMR and ¹⁵N-NMR spectroscopies. NMR analysis of the peat samples in the progressive heating stages showed the concentration of heterocyclic N-forms, the maximum structural transition amide-to-heterocyclic forms being observed in samples heated for 120 s (56% heterocyclic N and 34% aromatic C). Under more drastic conditions all N-forms were depleted. Correlation between spectroscopic and pyrolytic data betrayed specific pyrolytic markers for the different N-forms. The intensity of the ¹⁵N-NMR amide peak tended to be positively correlated to the yield of indoles, imidazoles and pyrazoles, and negatively correlated to those of benzonitriles and pyrazines. Analytical pyrolysis also showed a progressive enrichment in lipids and alkyl macromolecules with increasing heating intensity, and a decrease in lignin-derived, polysaccharide-derived and N-containing compounds. The relative abundance of non-methoxyphenolic aromatic compounds did not change. The N-compounds in peat samples unheated or heated for 60–90 s released methylpyrazole, dimethylpyrroline, methyldiphenylindole and pyrazole, whereas peat samples heated for 120 s mainly yielded methylpyrazine and methyldiphenylindole. Dimethylpyrroline and pyrazine prevailed in samples heated for 150 s, whereas samples heated for 180 s yielded mainly pyrrole. Pyrolysis data presented low possibilities for forecasting the extent of the O-alkyl domain, but reflected quantitatively the transformations in the lignin-like moiety. Both techniques coincide in pointing out the accumulation of a recalcitrant alkyl domain possibly derived from abiotic condensations or inherited lipid biomacromolecules.     

Bioavailability and metabolism of hexavalent chromium compounds †

Intratracheal instillation of ⁵¹CrCl₃ in anaesthetized rabbits resulted in partial absorption. In blood, the absorbed material was entirely confined to the plasma compartment. Only trace amounts were deposited in liver and kidney. By contrast, after similar application of Na, ⁵¹CrO₄ the bulk of blood radioactivity was present in red blood cells (RBC). Substantial deposition occurred in liver and kidneys. It is concluded that Cr(VI) may enter the body unreduced via the lung and is partially deposited in cells over a prolonged period of time.

Since chromium was accumulated in liver after administration of Cr(VI) we investigated the intracellular disposition of Cr(VI) in the isolated perfused liver. No significant sex differences in chromium distribution were observed. At the end of the experiments (1 h), 60% of the applied dose (312μg Cr/liver) was located in the cytosol, whilst 14% was in the mitochondria, 9% in the microsomal pellet and 2% was associated with the nuclei. Gel chromatography of the cytosolic compartment showed that the overwhelming part of chromium was eluted in fractions with an apparent molecular weight of 6,000 dalton. These fractions exhibited absorption maxima at 410nm and 548nm. It is concluded, that cytosolic reduction might be the main intracellular redox pathway for chromates. This view was confirmed by monitoring the reaction of Cr(VI) with GSH in vitro. GSH reduced Cr(VI) without further cofactors under formation of GSH‐chromium complexes, which possibly represent major intermediates in the metabolism of Cr(VI).     

负载多壁碳纳米管的多孔Ti/SnO2-Sb-Ni电极电催化氧化双酚A

为发展废水中双酚A（BPA）的处理技术和保护水环境安全,采用“电沉积-热分解”法制备负载多壁碳纳米管（MWCNTs）的多孔Ti/SnO₂-Sb-Ni电极,研究了电极对BPA的去除能力、动力学特征和矿化效率,初步分析了BPA的降解途径.结果表明,当浸渍液中n（Sn）∶n（Sb）∶n（Ni）为100∶10∶1、ρ（MWCNTs）为0.8g·L^-1时,制备的电极对BPA的去除效果最好;负载MWCNTs使得电极表面的晶体尺寸更小,可增大电极的比表面积,为电催化反应提供更多的活性位点,进而提高电极的电催化效率.当c（Na₂SO₄）为10mmol·L^-1、反应液初始pH为5和电流密度为50 mA·cm^-2时,对50 mg·L^-1的BPA降解60 min时去除效率达到99.76%;去除过程符合一级反应动力学方程,速率常数为0.096 min^-1;电解120 min时,TOC去除率达到67.01%.采用液相色谱-串联质谱分析法（...     

全氟和多氟烷基化合物微生物降解与转化研究进展

全氟和多氟烷基化合物(PFASs)因其持久性、长距离迁移性、生物积累性和生物毒性而受到广泛关注.目前世界上对环境中PFASs的监测和管控主要针对全氟烷基酸(PFAAs).而大部分多氟烷基化合物在环境中能够被微生物降解为PFAAs,也被称为前体物.因此,探究前体物在环境中的微生物转化行为有助于综合评价PFASs的环境风险,以及制定相关的管控和修复措施.虽然PFAAs一直被认为是环境中的“永久化合物”,但近年来,PFAAs的厌氧微生物还原脱氟作为一项极具潜力且充满挑战的修复技术,成为研究的一个前沿热点.系统总结了前体物(氟调化合物和全氟辛烷磺胺衍生物)、 PFAAs和新型PFASs在微生物作用下的降解规律和转化路径,并讨论了PFASs微生物降解的影响因素,最后提出未来的研究方向.     

电子束辐照降解水中氧氟沙星的研究

应用电子直线加速器初步探索了水体中氧氟沙星的辐照降解影响条件及降解机理.对初始浓度为20mg/L的氧氟沙星水溶液进行了辐照降解研究,分别选取了0.5kGy,1.0kGy,2.0kGy,3.0kGy,5.0kGy共5个剂量组,以研究辐照吸收剂量对降解效率的影响,同时分别对氧氟沙星水溶液进行空气饱和（水合电子清除剂）、氮气饱和、添加0.005mol/L及0.05mol/L氯化钠、添加0.05mol/L叔丁醇（羟基自由基清除剂）、添加0.005mol/L碳酸钠、添加0.005mol/L硫酸钠等方法进行处理,以探究降解过程中辐照水体产生自由基对氧氟沙星降解的贡献率.结果表明,以空气饱和进行处理,可提高氧氟沙星的降解率,辐照吸收剂量为2.0kGy时降解率可达99%.反之,加入氯化钠、叔丁醇和碳酸钠抑制了氧氟沙星的降解,加入硫酸钠则影响不大,表明羟基自由基在氧氟沙星降解中起关键作用.通过应用超高效液相色谱-质谱（UPLC-MS）对降解产物的分析鉴定,推测出了氧氟沙星的降解转化途径.