固相萃取-超高效液相色谱-串联质谱测定水中痕量苯甲地那铵

苯甲地那铵是一种广泛使用的苦味剂,近年来被发现在欧洲水体中普遍存在。建立灵敏可靠的环境样品前处理分析方法对评价其环境行为具有重要意义。通过优化关键前处理过程参数,建立了水中苯甲地那铵的固相萃取-超高效液相色谱串联质谱分析方法,系统考察了该方法的准确度、精密度、基质效应、检出限以及线性范围。研究表明：当调节水样pH至8以上,采用混合型阳离子交换小柱(200 mg, 3 mL)富集水样,采用含体积分数2%甲酸的甲醇溶液洗脱时,该方法可获得最佳回收率;纯水和环境水样中加标回收率分别为97%～105%和89%～119%,相对标准偏差小于7%;基质效应均在24%以内;方法检出限为0.07 ng/L,线性范围为0.01～50μg/L。该方法可用于环境水体中苯甲地那铵的痕量检测。     

Fraction characteristics of rare earth elements in the surface sediment of Bohai Bay, North China

Surface sediment samples were collected at 27 stations of Bohai Bay, North China. Sequential extractions were carried out in this study. REE were leached out from four labile fractions: Exchangeable (L1), bound to carbonates (L2), bound to Fe–Mn oxides (L3), bound to organic matter (L4), and the remainder was residual (R5). The total contents of REE fluctuate slightly in Bohai Bay, and are mainly concentrated in the middle region, showing relatively higher levels in the north than that in the south of Bohai Bay. Percentages of L1, L2, L3, L4, and R5 for REE suggest that the residual fraction accounts for the major component of REE, whereas Fe–Mn oxides also play important roles in combining labile REE. As the REE complex is not stabilized, the competition of complex could induce dissociation of the complex and redistribution of the REE in various environments. According to REE patterns and Y/Ho ratios of samples, REE are not anthropogenic or oceanic sources but riverine input, whereas suitable environment varieties can slightly affect the patterns and fractionations of REE. As powerful tracers for the variable of environment, higher anomaly of Eu and Ce in southern regions indicates a greater reduction in the condition of surface sediment in the south than that in the north of Bohai Bay.     

基于激光雷达和超级站监测的一次沙尘过程分析

利用南京市气溶胶激光雷达网和草场门超级站监测数据,对2022年3月2—3日南京地区一次沙尘污染过程的垂直特征和地面PM_2.5组分变化进行了分析。结果表明,草场门、八卦洲和土桥3处点位的气溶胶激光雷达均观测到消光系数和退偏振比在凌晨至清晨时段有垂直分层现象,说明高空输入的沙尘气团位于城市污染气团上空,而此时地面PM_2.5组分以二次无机盐(硝酸盐、硫酸盐和铵盐)为主。中午前后,各高度的退偏振比及消光系数发生突变,主要是由高空输入沙尘和城市污染气团的垂直混合引起的。随着日间大气垂直交换的加大,PM_2.5中地壳物质的浓度均值和占比显著上升,其中浓度从3 μg/m³升高至5 μg/m³,占比从3%上升至10%。     

pH-dependent release characteristics of antimony and arsenic from typical antimony-bearing ores

The pH-dependent leaching of antimony (Sb) and arsenic (As) from three typical Sb-bearing ores (Banxi, Muli and Tongkeng Antimony Mine) in China was assessed using a pH-static leaching experiment. The pH changes of the leached solutions and pH-dependent leaching of Sb and As occurred in different ways. For the Banxi and Muli Sb ores, alkaline conditions were more favorable for the release of Sb compared to neutral and acidic conditions, but the reverse was true for the pH-dependent release of As. For the Tongkeng Sb ore, unlike the previous two Sb-bearing ores, acidic conditions were more favorable for Sb release than neutral and alkaline conditions. The ores with lower Sb and As contents released higher percentages of their Sb and As after 16 day leaching, suggesting that they are the largest potential sources of pollution. This work may provide key information on the geochemistry of Sb and As in the weathering zone.     

长江流域重点断面水质时空变异特征及污染源解析

为明晰长江流域水质时空分布特征并解析污染源,基于长江流域21个水质监测断面2008—2018年的pH、溶解氧(DO)、高锰酸盐指数(COD_Mn)及氨氮质量浓度([NH₃-N])数据,采用M-K趋势检验、相关性分析和层次聚类分析,对流域内水质时空动态变化趋势及特征进行综合识别,并结合绝对主成分回归分析法(APCS-MLR)解析污染物来源。结果表明,研究区内重点断面水质类别以II类为主,占71.39%。在时间上,水质污染程度表现为汛期(5—10月)劣于非汛期(1—4月和11、12月),汛期主要污染指标为DO和COD_Mn,非汛期主要污染指标为[NH₃-N];在空间上,21个监测断面聚类为3组,其水质优劣排序为GⅢ(四川乐山岷江大桥、湖南长沙新港、江西南昌滁搓站点)>GⅡ(中下游及下游)>GⅠ(上游及中上游)。结合主成分分析和多元回归分析得出,在所基于的指标中COD_Mn和NH₃-N是研究区内典型污染物,GⅠ组水体主要受营养盐面源污染和耗氧有机物蓄积污染;GⅡ组水质受工业生产和人类活动影响其营养盐和有机物污染严重,而自然因素影响较弱;GⅢ组站点属局部污染严重,污染源主要是有机物,其次是营养盐。上述研究结果可为长江流域针对性水环境治理、污染控制和改善提供参考。     

Antimony leaching release from brake pads: Effect of pH,temperature and organic acids

Metals from automotive brake pads pollute water, soils and the ambient air. The environmental effect on water of antimony(Sb) contained in brake pads has been largely untested. The content of Sb in one abandoned brake pad reached up to 1.62 × 104mg/kg.Effects of initial p H, temperature and four organic acids(acetic acid, oxalic acid, citric acid and humic acid) on Sb release from brake pads were studied using batch reactors.Approximately 30%(97 mg/L) of the total Sb contained in the brake pads was released in alkaline aqueous solution and at higher temperature after 30 days of leaching. The organic acids tested restrained Sb release, especially acetic acid and oxalic acid. The p H-dependent concentration change of Sb in aqueous solution was best fitted by a logarithmic function. In addition, Sb contained in topsoil from land where brake pads were discarded(average9 × 103mg/kg) was 3000 times that in uncontaminated soils(2.7 ± 1 mg/kg) in the same areas. Because potentially high amounts of Sb may be released from brake pads, it is important that producers and environmental authorities take precautions.? 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences.     

Eukaryotic community diversity and pathogenic eukaryotes in a full-scale drinking water treatment plant determined by 18S rRNA and metagenomic sequencing

Environmental Science and Pollution Research - In this study, 18S rRNA high-throughput sequencing was applied to investigate the eukaryotic community in a full-scale drinking water treatment plant....     

十溴联苯醚(BDE 209)暴露对孕期大鼠和胎鼠甲状腺激素干扰效应研究

为探讨孕期十溴联苯醚(BDE 209)暴露对孕期羊水和胎鼠循环甲状腺激素(TH)的影响及其对胎脑发育的损害作用,将24只Wistar雌性大鼠随机分为对照组、BDE 209低剂量组(100 mg·kg-1 bw)和高剂量组(300 mg·kg-1 bw),与雄鼠合笼,经阴道涂片确认受孕后,在孕1 d给予BDE 209经口持续灌胃染毒至孕15 d(GD15)和孕20 d(GD20).在GD15和GD20这2个时间点麻醉母鼠后剥离胎鼠称取体质量;应用酶联免疫吸附剂测定(ELISA)检测GD15、GD20羊水及GD20胎鼠循环TH水平,包括总三碘甲状腺原氨酸(TT3)、血清游离三碘甲腺原氨酸(FT3)、血清总甲状腺素(TT4)、游离甲状腺素(FT4)和促甲状腺激素(TSH)水平;应用实时荧光定量PCR(RT-qPCR)法检测胎脑促甲状激素释放激素(thyrotropin-releasing hormone,Trh)基因相对表达;应用苏木精-伊红染色(HE染色)观察GD20胎脑形态学改变.结果表明:(1)高剂量BDE 209可引起胎鼠体质量异常改变.(2)BDE 209可引起孕期羊水和孕后期胎鼠循环TH水平紊乱,表现为GD15时,BDE 209可引起羊水FT3下降、TT4和TSH增高,但未见统计学意义;低、高剂量BDE 209均可引起羊水FT4水平升高(P<0.05或P<0.01),且具有剂量依赖性.GD20时,与GD15相比,对照组羊水TH水平有所变化,FT3和TT4水平均明显增高,而TSH水平有所降低;低、高剂量BDE 209引起FT3显著降低(P<0.05),FT4在高剂量组升高(P<0.05);低、高剂量BDE 209引起TSH水平显著升高(P<0.05).GD20时,胎鼠血清TH变化与同时期羊水中的基本一致,BDE 209可致胎鼠血清FT3和TT4下降,虽然没有显著性差异,胎鼠血清TSH水平增高,尤其在高剂量组(P<0.05).(3)BDE 209可导致孕育中胎脑Trh基因表达下调(P<0.05),并随着孕期进程而加重.(4)病理学观察发现BDE 209可引起孕末期胎鼠脑细胞结构发生变化,使细胞数量减少,脑组织出现萎缩.综上,孕期BDE 209暴露可影响胚胎大鼠生长发育;引起羊水TH水平紊乱、胚胎大鼠循环TH水平紊乱以及胚胎脑组织Trh基因表达抑制,导致脑组织结构产生病理改变.这些可能是BDE 209致子代发育神经毒性的病理基础.     

Diffusive gradients in thin films (DGT) probe for effectively sampling of per- and polyfluoroalkyl substances in waters and sediments

The passive sampling technique, diffusive gradients in thin films (DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per- and polyfluoroalkyl substances (PFAS). However, its effectiveness has been questioned because of the small effective sampling area (3.1 cm²). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area (27 cm²) and as a result lower method quantification limits (0.15 – 0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher (by > 10 factors) sampling rate (100 mL/day) compared to the standard DGT (piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling (500 mL). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.     

Efficient microwave-assisted photocatalytic degradation of endocrine disruptor dimethyl phthalate over composite catalyst ZrOx/ZnO

A highly active ZrOx/ZnO catalyst for microwave-assisted photocatalytic (MW/PC) degradation of endocrine disruptor dimethyl phthalate (DMP) has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrOx/ZnO was characterized by XPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences (+2, +3, +4) co-existed in ZrOx/ZnO. By using the ZrOx/ZnO (0.1 g), the TOC removal efficiency of DMP (100 mL of 50 mg/L) was 88% after 30 min reaction, which was about 15% higher than P25 TiO2. It was found that the removal process of DMP by MW/PC followed pseudo first-order kinetics in all cases, and ZrOx/ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP was shortened 45% compared with P25 TiO2. A possible catalytic mechanism was proposed based on microwave response and interfacial charge transfer. ZrOx/ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insights into designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation.