滆湖水华初期浮游植物群落特征及与水环境因子相关性分析

为探究滆湖水华初期浮游植物群落特征及与水环境因子的相关性,于2018年5—7月在全湖布设22个点,调查研究滆湖水华初期浮游植物群落时空分布特征,并对引起水华主导环境因子进行分析.结果表明：①共获得7门119属,优势属为绿藻门的小球藻与球团藻、蓝藻门的鞘丝藻与微囊藻,其中湖心区域浮游植物丰度与多样性小,均匀性低,属于中偏重污染区域;湖北区以北属于中污染区域,蓝藻堆积严重;西部沿岸及南端区域属于中偏轻污染区域.②冗余分析得出,湖心藻类与水温（T）有强相关性,与叶绿素a（Chl-a）、溶解性总磷（DTP）、pH、溶解氧（DO）呈一定正相关性;湖北区以北藻类与底泥有机质（OM）、水体悬浮物（SS）、Chl-a及DTP呈强相关性,与T呈一定相关性.T与多项环境因子相关,均值从26.1℃上升到32.4℃;OM与有机磷（OP）呈高度相关性（p<0.05,r=0.892）.水华发生的主导环境因子为T、DTP与pH,底泥OM及OP有一定影响.     

南京市饮用水源地抗生素污染特征及风险评估

采用固相萃取-液相色谱-串联质谱技术（SPE-HPLC-MS/MS）,对南京市饮用水源地抗生素含量及分布特征进行了分析.结果表明,17个采样点总浓度为0.56~1994.96 ng·L^-1,共检出5种大环内酯类、13种磺胺类、3种四环素类、8种喹诺酮类抗生素,平均浓度为0.30~37.07 ng·L^-1,其中检出浓度最高的抗生素为环丙沙星（CIP）,浓度为317.60 ng·L^-1,检出率最高的抗生素为克林霉素（CLI）,检出率为88.24%.与国内部分河流相比,南京市饮用水源地水体中大环内酯类、四环素类、喹诺酮类抗生素残留浓度处于较高水平.生态风险评估结果表明,点位S7具有最高的联合风险熵值（24.58）,氧氟沙星（OFX）的风险熵值最高,达到13.06;健康风险评估结果表明,9种抗生素对人体健康的风险熵Q_H为1.70×10^-3~9.47,强力霉素（DOX）、诺氟沙星（NOR）、恩诺沙星（ERX）、CIP和OFX对大部分年龄段的人体健康具有高水平风险.     

我国硒淡水水生生物水质基准值推导

水体中硒含量过高会导致水生生态系统退化,而中国现有的地表水环境质量标准对硒的标准值设定并不是基于我国水生生物相关毒理学研究得出的,难以因地制宜地保护我国水生生物.为保护我国水生生物,本研究利用物种敏感度分布法,推导出基于最大无效应浓度（NOEC）、最低有效应浓度（LOEC）的慢性硒（无机）淡水水质一级基准值和基于半数致死效应浓度（LC₅₀）、半数最大效应浓度（EC₅₀）、半数抑制浓度（IC₅₀）的急性硒（无机）淡水水质二级基准值分别为0.58 μg·L^-1、0.52 mg·L^-1,发现我国现有的水质标准可能会对我国水生生物造成欠保护.进一步推导出为保护我国鱼类的硒（无机）淡水水质一级、二级基准值分别为0.21 μg·L^-1、1.60 mg·L^-1,以及硒淡水鱼类饲料有机硒和无机硒含量一级基准值分别为97 μg·kg^-1和98 μg·kg^-1.本研究基于硒对水生生物的急性和慢性毒性效应,推导出硒的系列基准值,为保护我国淡水水生生物安全的标准制定提供数据支撑和科学依据.     

裂解温度和离子强度对不同来源生物炭胶体释放行为的影响

近年来环境中生物炭胶体形成受到广泛关注,它是生物炭在环境中物理分解作用的重要过程,对污染物迁移有着重要影响.然而,目前对生物炭胶体释放过程和影响因素的研究甚少,人们对生物炭胶体释放机理的认识还很有限.本研究以小麦秸秆和花生壳为生物质来源,系统地探讨了生物炭的裂解温度（300~700 ℃）和溶液离子强度（0.1~10 mmol·L^-1）对生物炭胶体产率的影响.结果表明,随着裂解温度的升高,生物炭的耐磨性增强,且在较高的裂解温度下（≥500 ℃）花生壳生物炭的耐磨性显著强于小麦秸秆生物炭.生物炭的胶体产率受到生物质来源和裂解温度的显著影响,花生壳生物炭的胶体产率低于小麦秸秆生物炭,高温裂解（≥600 ℃）生物炭的胶体产率显著低于中低温裂解生物炭.在相同溶液离子强度下,生物炭胶体产率与其亚微米级碎片率呈显著正相关（p<0.05）,即生物炭中亚微米级碎片率越高,生物炭胶体产率越高.当溶液离子强度从1 mmol·L^-1增加到10 mmol·L^-1时,两种来源生物炭的胶体产率均显著降低,其降低的程度因生物炭裂解温度而异,其中低温裂解（300 ℃）生物炭的胶体产率降低了11.1%~11.2%,中高温裂解（≥ 500 ℃）生物炭的胶体产率降低了60.0%~97.2%.     

金属改性对SAPO-34低温还原NO性能的影响

采用浸渍法制备金属改性SAPO-34分子筛催化剂,分析比较了不同单金属（Cu或Co）及不同比例双金属（Cu：Co=1：1、3：1、5：1,质量比）改性催化剂对NO的催化还原性能,评价了不同催化剂的N₂选择性,并采用扫描电子显微镜（SEM）、比表面积测试、X射线衍射分析（XRD）、NH₃-程序升温脱附（NH₃-TPD）等表征手段对催化剂的物化性能进行了分析.结果表明,单金属Cu改性催化剂具有较宽的温度区间,在250~450℃范围内NO的转化率始终保持在100%;双金属改性使NO转化率保持为100%的最低温度下降了25~50℃,显著拓宽了低温段窗口,其中,Cu₃Co₁/SAPO-34催化剂的低温催化还原性能最好,200℃即可实现100%的NO转化率,175℃下的转化率也高达80%以上.Cu-Co双金属改性SAPO-34分子筛催化剂具有优异的低温催化还原NO性能,具有在机动车尾气、工业废气的低温脱硝治理领域应用的潜力.     

黑河流域底栖动物群落结构及水质评价

为了解黑河流域上中游底栖动物群落结构特征及其与环境因子之间的关系,于2018年8月对研究区域17个采样点的底栖动物和水体理化指标进行调查研究.共鉴定出底栖动物43种,其中节肢动物34种（79.1%）,软体动物7种（16.3%）,环节动物2种（4.6%）;就整个研究区域而言,优势种为大蚊（Tipulidae）、豆娘幼虫（Damselfly）、水蜘蛛（Argyroneta）、耳萝卜螺（Radix auricularia）、琥珀螺（Suecinea sp.）、白旋螺（Gyraulusalbus）,干、支流优势种分布趋势为干流（6种）优于支流（5种）;底栖动物平均密度和平均生物量分别为77ind/m²和3.7423g/m²现存量存在显著空间差异,整体上干流（1032ind/m²、60.0963g/m²）大于支流（276ind/m²、3.5233g/m²）,物种数干流（36种）大于支流（15种）;单因素方差分析显示,Shannon-Wiener多样性指数、Margalef丰富度指数及Pielou均匀度指数分布特征为干流大于支流.黑河流域上游支流和中游干流不同河段底栖动物物种组成呈空间异质性,而多样性指数对物种组成依赖性强,但因黑河流域底栖动物物种组成受自然因素和人类活动双重影响程度差异较大,使得Shannon-Wiener多样性指数、Margalef丰富度指数及Pielou均匀度指数不适合黑河水质评价.依据BI指数和综合污染指数评价表明,黑河上游支流水质优于中游干流.根据底栖动物与环境因子之间的相关矩阵分析并结合RDA分析表明：BOD₅、水温（WT）、电导率（EC）、DO、溶解性总固体（TDS）、COD_Mn及盐度是影响底栖动物群落结构的主要环境因子.     

Bioassay: A useful tool for evaluating reclaimed water safety

Wastewater reclamation and reuse has been proved to be an effective way to relieve the fresh water crisis. However, toxic contaminants remaining in reclaimed water could lead to potential risk for reuse, and the conventional water quality standards have difficulty guaranteeing the safety of reclaimed water. Bioassays can vividly reflect the integrated biological effects of multiple toxic substances in water as a whole, and could be a powerful tool for evaluating the safety of reclaimed water. Therefore, in this study, the advantages and disadvantages of using bioassays for evaluating the safety of reclaimed water were compared with those of conventional water quality standards. Although bioassays have been widely used to describe the toxic effects of reclaimed water and treatment efficiency of reclamation techniques, a single bioassay cannot reflect the complex toxicity of reclaimed water, and a battery of bioassays involving multiple biological effects or in vitro tests with specific toxicity mechanisms would be recommended. Furthermore, in order to evaluate the safety of reclaimed water based on bioassay results, various methods including potential toxicology, the toxicity unit classification system, and a potential eco-toxic effects probe are summarized as well. Especially, some integrated ranking methods based on a bioassay battery involving multiple toxicity effects are recommended as useful tools for evaluating the safety of reclaimed water, which will benefit the promotion and guarantee the rapid development of the reclamation and reuse of wastewater.     

Effects of SO2 and H2O on low-temperature NO conversion over F-V2O5-WO3/TiO2 catalysts

F-V_2 O_5-WO3/Ti02 catalysts were prepared by the impregnation method.As the content of F ions increased from 0.00 to 0.35 wt.%,the NO conversion of F-V_2 O_5-WO_3/TiO_2 catalysts initially increased and then decreased.The 0.2 F-V_2 O_5-WO_3/TiO_2 catalyst(0.2 wt.% F ion)exhibited the best denitration(De-NOx) performance,with more than 95% NO conversion in the temperature range 160-360℃,and 99.0% N2 selectivity between 110 and 280℃.The addition of an appropriate amount of F ions eroded the surface morphology of the catalyst and reduced its grain size,thus enhancing the NO conversion at low temperature as well as the sulfur and water resistance of the V_2 O_5-WO3/Ti02 catalyst.After selective catalytic reduction(SCR) reaction in a gas flow containing SO_2 and H_2 O,the number of NH3 adsorption sites,active component content,specific surface area and pore volume decreased to different degrees.Ammonium sulfate species deposited on the catalyst surface,which blocked part of the active sites and reduced the NO conversion performance of the catalyst.On-line thermal regeneration could not completely recover the catalyst activity,although it prolonged the cumulative life of the catalyst.In addition,a mechanism for the effects of S02 and H_2 O on catalyst NO conversion was proposed.     

Revealing the changes of bacterial community from water source to consumers tap: A full-scale investigation in eastern city of China

This study profiled the bacterial community variations of water from four water treatment systems, including coagulation, sedimentation, sand filtration, ozonation-biological activated carbon filtration (O₃-BAC), disinfection, and the tap water after the distribution process in eastern China. The results showed that different water treatment processes affected the bacterial community structure in different ways. The traditional treatment processes, including coagulation, sedimentation and sand filtration, reduced the total bacterial count, while they had little effect on the bacterial community structure in the treated water (before disinfection). Compared to the traditional treatment process, O₃-BAC reduced the relative abundance of Sphingomonas in the finished water. In addition, ozonation may play a role in reducing the relative abundance of Mycobacterium. NaClO and ClO₂ had different effects on the bacterial community in the finished water. The relative abundance of some bacteria (e.g. Flavobacterium, Phreatobacter and Porphyrobacter) increased in the finished water after ClO₂ disinfection. The relative abundance of Mycobacterium and Legionella, which have been widely reported as waterborne opportunistic pathogens, increased after NaClO disinfection. In addition, some microorganisms proliferated and grew in the distribution system, which could lead to turbidity increases in the tap water. Compared to those in the finished water, the relative abundance of Sphingomonas, Hyphomicrobium, Phreatobacter, Rheinheimera, Pseudomonas and Acinetobacter increased in the tap water disinfected with NaClO, while the relative abundance of Mycobacterium increased in the tap water disinfected with ClO₂. Overall, this study provided the detailed variation in the bacterial community in the drinking water system.     

Effects of calcination temperature on physicochemical property and activity of CuSO4/TiO2 ammonia-selective catalytic reduction catalysts

CuSO_4/TiO_2 catalysts with high catalytic activity and excellent resistant to SO_2 and H_2 O,were thought to be promising catalysts used in Selective catalytic reduction of nitrogen oxides by NH_3.The performance of catalysts is largely affected by calcination temperature.Here,effects of calcination temperature on physicochemical property and catalytic activity of CuSO_4/TiO_2 catalysts were investigated in depth.Catalyst samples calcined at different temperatures were prepared first and then physicochemical properties of the catalyst were characterized by N2 adsorption-desorption,X-ray diffraction,thermogravimetric analysis,Raman spectra,Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,temperature-pro grammed desorption of NH_3,temperature-programmed reduction of H_2 and in situ diffuse reflectance infrared Fourier transform spectroscopy.Results revealed that high calcination temperature had three main effects on the catalyst.First,sintering and anatase transform into rutile with increase of calcination temperature,causing a decrement of specific surface area.Second,decomposition of CuSO_4 under higher calcination temperature,resulting in disappears of Br(?)nsted acid sites(S-OH),which had an adverse effect on surface acidity.Third,CuO from the decomposition of CuSO_4 changed surface reducibility of the catalyst and favored the process of NH_3 oxidation to nitrogen oxides(NO_x).Thus,catalytic activity of the catalyst calcined under high temperatures(≥600℃) decreased largely.