臭氧耦合陶瓷膜过滤对膜性能及出水消毒副产物的影响

利用臭氧（O₃）-陶瓷膜过滤（CMF）处理常规工艺出水,研究了不同O₃-CMF耦合方式对膜性能和消毒副产物（DBPs）的影响.结果表明,与单独CMF相比,异位O₃-CMF和原位O₃-CMF均可以有效缓解膜污染,原位O₃-CMF控制效果最佳.异位O₃-CMF对进水（常规工艺出水） DOC去除率（26.25%）略高于原位O₃-CMF（22.31%）,但是其SUVA去除率（83.91%）明显低于原位O₃-CMF（93.10%）.羟基自由基（·OH）生成特征表明原位O₃-CMF可促进O₃产生更多的·OH.在O₃、·OH氧化和陶瓷膜截留协同作用下,异位O₃-CMF和原位O₃-CMF出水中总荧光响应强度和相对分子质量大于0.3×10³,有机物含量降低,进而使得出水中含碳消毒副产物（C-DBPs）生成量分别降低了21.86%和32.35%,含氮消毒副产物（N-DBPs）生成量分别降低了16.16%和19.13%.但O₃和·OH氧化后生成的小分子有机物因难以被CM截留导致其在出水中含量增加,进而增加了卤代酮（HKs）、水合氯醛（CH）和三卤硝基甲烷（THNMs）的产生.本研究对于不同O₃-CMF方式下O₃与CM的协同机制的探讨,改善膜性能和提升DBPs前体物的去除具有一定指导意义.     

EFFECTS OF STATSGO AND SSURGO AS INPUTS ON SWAT MODEL'S SNOWMELT SIMULATION1

ABSTRACT: Soil data comprise a basic input of SWAT (Soil and Water Assessment Tool) for a watershed application. For watersheds where site specific soil data are unavailable, the two U.S. Department of Agriculture (USDA) soil databases, the State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) databases, may be the best alternatives. Although it has been noted that SWAT models using the STATSGO and SSURGO data may give different simulation results for water, sediment, and agricultural chemical yields, information is scarce on the effects of using these two databases in predicting streamflows that are predominantly generated from melting snow in spring. The objective of this study was to assess the effects of using STATSGO versus SSURGO as an input for the SWAT model's simulation of the streamflows in the upper 45 percent of the Elm River watershed in eastern North Dakota. Designating the model as SWAT‐STATSGO when the STATSGO data were used and SWAT‐SSURGO when the SSURGO data were used, SWAT‐STATSGO and SWAT‐SSURGO were separately calibrated and validated using the observed daily streamflows. The results indicated that SWAT‐SSURGO provided an overall better prediction of the discharges than SWAT‐STATSGO, although both did a good and comparable job of predicting the high streamflows. However, SWAT‐STATSGO predicted the low streamflows more accurately and had a slightly better performance during the validation period. In addition, the discrepancies between the discharges predicted by these two SWAT models tended to be larger at upstream locations than at those farther downstream within the study area.     

江苏泰州城市霾天和沙尘天气溶胶中细菌群落结构特征研究

近年来,空气污染已成为长三角地区最关键的环境问题之一,气溶胶颗粒物(PM)是最主要的污染物之一.生物气溶胶作为颗粒物的重要组成部分,可能对空气质量和人体健康产生不利影响.利用高通量测序方法研究了江苏省泰州2019年11月至2020年1月期间发生沙尘和霾污染时生物气溶胶中细菌群落结构组成特征.结果表明:冬季沙尘天和霾天气...     

甘肃某冶炼厂区土壤重金属铅、镉污染特征及其对微生物群落结构的影响

长期受到重金属铅(Pb)和镉(Cd)污染的土壤生态危害指数较高,土壤微生物群落结构容易受到重金属的影响,重金属对土壤微生物的毒性与重金属的生物利用度直接相关。以白银市重金属污染土壤为样本,分析了土壤的理化性质、重金属Pb和Cd的污染状况及土壤微生物群落结构,探究它们之间的关联性。样本采自距离污染中心由近及远的4个位置(分别命名为S1、S2、S3和S4)。采用Hakanson指数法来评估该地重金属生态风险;选用改进的BCR顺序提取法分析Pb与Cd的组分分布情况;利用SPSS和Canoco 4.5对土壤性质、重金属和细菌群落进行相关性分析和冗余分析,探究微生物群落结构与土壤性质和重金属污染之间的相关性。结果表明:白银市该处重金属污染场地3 km以内的土壤均受到严重的Pb、Cd污染。Pb主要以弱酸可提取态和可还原态的形式存在于土壤中,Cd则以弱酸可提取态为主;土壤重金属的危害生态指数均已经达到极高污染风险程度,且危害程度S1>S3>S2>S4;微生物丰度和多样性可能受到土壤性质及重金属的共同影响,与Pb、Cd的污染程度大致呈负相关(S2相似文献   

乙草胺、丁草胺和异丙甲草胺在室外天然水中的非生物降解及其影响因素

在亚热带冬、夏两季室外自然光照和温度条件下,研究了环境浓度下乙草胺、丁草胺和异丙甲草胺在河水和海水基底中的非生物降解(水解+光解)行为,并结合室内实验研究了非生物降解的影响因素.室外实验结果表明,冬季(气温12.30—26.98℃,平均17.47℃)乙草胺、丁草胺和异丙甲草胺在河水中的非生物降解半衰期(t1/2)为64—131 d、水解t1/2为105—346 d、光解t1/2为159—410 d,海水中非生物降解t1/2为89—193 d、水解t1/2为77—277 d、光解t1/2为417—630 d;夏季(气温20.77—30.37℃,平均27.22℃)3种目标农药在河水中非生物降解t1/2为4—20 d、水解t1/2为7—54 d、光解t1/2为7—32 d,海水中非生物降解t1/2为10—50 d、水解t1/2为23—67 d、光解t1/2为17—192 d.目标农药在海水中的残留持久性远高于河水;超纯水条件下,光解在目标农药的非生物降解中占主导地位;河水中的光解速率快于海水.室内实验发现,硝酸盐促进了3种目标农药的水解,同时对乙草胺和丁草胺的光解也起到促进作用;p H升高促进了异丙甲草胺的水解和光解速率,但是抑制了丁草胺的水解和乙草胺、丁草胺的光解;腐殖质添加浓度为10 mg·L-1和20 mg·L-1时促进了3种目标农药的水解,但在浓度达30 mg·L-1时则抑制了乙草胺的水解及异丙甲草胺的光解.总体而言,3种目标农药在实际水环境中的降解半衰期均较长,其降解机理和毒性效应值得进一步研究.     

郑州与福州降水同位素特征及水汽来源对比分析

研究基于郑州与福州两地区GNIP(1985—1992年)大气降水同位素资料,对其大气降水同位素的季节变化以及环境因子进行比较分析。结果表明,郑州地区较福州地区季节变化明显,且两地区与温度和降水量均呈现负相关关系;根据两地区大气降水线方程得出,福州地区大气降水线方程斜率和截距大于郑州地区;两地区的d-excess值夏季高,冬季低;福州地区受台风影响,两地区降水量差别较大导致降水量在决定两地区月加权平均d-excess值时,福州地区整体比郑州地区偏大;采用MeteoInfo软件,并利用由美国国家大气研究中心所提供的气象资料,对两地区气团轨迹进行后向模拟,比较分析得出:郑州地区在夏季大部分水汽来自南海,春季、秋季和冬季的水汽均来自北方大陆;福州地区在夏季的水汽全部水汽来自低纬度的海洋,而春季、秋季和冬季的水汽仅有少部份来自北方大陆。     

江西省兴国县土壤侵蚀动态监测研究

介绍发应用遥感技术和调查资料编制的江西省兴国县三个时期（１９５８，１９７５，１９８８年）的土壤侵蚀动态监测图。结果表明，建国以来，该县水土流失的动态变化基本上呈抛物线的态势发展，目前水土流失面积在缩小，程度在降低，总的趋势向好的方向发展。     

龙川江楚雄站碳侵蚀通量的动态分析

选取龙川江楚雄水文站进行了为期3年的采样,分析了水体中各形式碳的含量,并估算各碳的输送通量.结果表明:楚雄站3年的碳通量(FTC)分别为27.12×106g·km-2·a-1、24.87×106g·km-2·a-1和10.34×106g·km-2·a-1,分析流域在对碳输送过程中,以输送无机碳为主,分别占输送总量的89.7%、90.3%及91.9%;而汛期碳输送量分别占全年总量的90.9%、84.9%和83.8%,表现出流域汛期对碳的搬运量远远高于非汛期;溶解性有机碳通量(FDOC)与颗粒有机碳通量(FPO C)平均比为0.82,不同季节表现情况不一,非汛期溶解性有机碳(DOC)与颗粒有机碳(POC)含量相当,汛期机械侵蚀作用增强,导致FPO C远远大于FDOC,反映汛期对流域侵蚀作用以机械剥蚀为主,化学侵蚀为辅.研究期内恰遇2008年一场洪水,11月碳的侵蚀通量为8.53×106g·km-2·a-1,其中溶解性无机碳(DIC)、溶解性有机碳(DOC)和颗粒有机碳(POC)的输送量分别为7.37×106、0.36×106、0.80×106g·km-2·a-1,分别占2008年全年相应形式碳总量的33.3%、34.4%和59.9%,为当年非汛期碳侵蚀总量的2.3倍,反映洪水期的碳输出量对流域碳输出总量及构成存在不可忽略的贡献.     

Water Quality Changes as a Result of Coalbed Methane Development in a Rocky mountain Watershed1

Abstract: Coalbed methane (CBM) development raises serious environmental concerns. In response, concerted efforts have been made to collect chemistry, salinity, and sodicity data on CBM produced water. However, little information on changes of stream water quality resulting from directly and/or indirectly received CBM produced water is available in the literature. The objective of this study was to examine changes instream water quality, particularly sodicity and salinity, due to CBM development in the Powder River watershed, which is located in the Rocky Mountain Region and traverses the states of Wyoming and Montana. To this end, a retrospective analysis of water quality trends and patterns was conducted using data collected from as early as 1946 up to and including 2002 at four U.S. Geological Survey gauging stations along the Powder River. Trend analysis was conducted using linear regression and Seasonal Kendall tests, whereas, Tukey’s test for multiple comparisons was used to detect changes in the spatial pattern. The results indicated that the CBM development adversely affected the water quality in the Powder River. First, the development elevated the stream sodicity, as indicated by a significant increase trend of the sodium adsorption ratio. Second, the development tended to shrink the water quality differences among the three downstream stations but to widen the differences between these stations and the farthest upstream station. In contrast, the development had only a minor influence on stream salinity, as indicated by that the stream electrical conductivity exhibited either no trend or a marginally significant positive trend. Hence, the CBM development is likely an important factor that can be managed to lower the stream sodicity. The management may need to take into account that the effects of the CBM development were different from one location to another along the Powder River.