有机污染胁迫对人工湿地中浮萍抗氧化系统的影响

湿地植物在处理高负荷有机废水时会受到不同程度的氧化胁迫。本研究基于对浮萍的有机污染胁迫模拟系统,通过对浮萍脂质过氧化和抗氧化防御系统的监测与分析,研究了浮萍对有机污染胁迫的耐受能力及胁迫去除后浮萍的恢复规律。结果表明,浮萍对有机污染胁迫具有较高的耐受性,在胁迫去除后,具有一定的恢复能力。在COD小于400mg/L时,浮萍并未受到氧化胁迫;当COD达到800 mg/L时,浮萍体内ROS含量上升,细胞膜脂过氧化加剧,但抗氧化酶活性升高,抗氧化物质含量增加,浮萍可保持生长,胁迫去除后,抗氧化防御系统可恢复到对照水平;当COD过高（≥1 000mg/L）,ROS急剧上升,抗氧化防御系统遭受破坏,造成不可逆伤害,胁迫去除后不能恢复正常生长。     

畜禽沼液中抗生素和激素的微波处理

通过间歇处理和连续处理实验,探讨微波技术对沼液中四环素类抗生素和激素喹乙醇去除的效果。结果表明,沼液在微波间歇处理中,最优反应时间为40min。此条件下沼液中喹乙醇、土霉素、四环素和金霉素的去除率分别达到26％、49％、48％和70％;微波可显著提高可生化性,BOD5／COD值达到0．37。微波一好氧处理系统中COD与氨氮的去除率分别达到91％和93％,明显优于单独好氧处理。沼液微波连续处理中,最优HRT为90min,此时喹乙醇、土霉素、四环素和金霉素的去除率分别达到24％、45％、50％和74％;BOD5／COD值达到0．34。微波．好氧处理系统中COD与氨氮的去除率均为90％,优于单独好氧处理效果。     

膜电解法在线再生酸性蚀刻液及回收铜新技术

采用极化曲线法研究了酸性蚀刻液阴、阳极电化学行为,并构建了离子膜电解反应体系,考察了在线再生酸性蚀刻液及回收铜的效果。结果表明,阳极氧化过程发生浓差极化,存在极限电流密度,Cu＋含量越高,极限电流密度越大;阴极还原分4步反应进行,存在极限电流密度;强化溶液传质可有效提高阴、阳极极限电流密度,有利于避免电解过程中析出氯气和氢气;在线实验表明,通过监控阳极液ORP,可避免析出氯气;分步降低电流电解有利于避免析出氢气,形成致密的金属铜块;在电流为9～24A范围内分4步电解23．5h可再生酸性蚀刻液23．5L,同时电沉积回收510g铜,纯度高达99．98％。阴极电流效率达到95．2％,吨铜电耗3251kWh。电解过程中无氯气和氢气析出,无废液排放,表明膜电解法在线再生酸性蚀刻液具有良好的应用前景。     

An integrated approach to model the biomagnification of organic pollutants in aquatic food webs of the Yangtze Three Gorges Reservoir ecosystem using adapted pollution scenarios

The impounding of the Three Gorges Reservoir (TGR) at the Yangtze River caused large flooding of urban, industrial, and agricultural areas, and profound land use changes took place. Consequently, substantial amounts of organic and inorganic pollutants were released into the reservoir. Additionally, contaminants and nutrients are entering the reservoir by drift, drainage, and runoff from adjacent agricultural areas as well as from sewage of industry, aquacultures, and households. The main aim of the presented research project is a deeper understanding of the processes that determines the bioaccumulation and biomagnification of organic pollutants, i.e., mainly pesticides, in aquatic food webs under the newly developing conditions of the TGR. The project is part of the Yangtze-Hydro environmental program, financed by the German Ministry of Education and Science. In order to test combinations of environmental factors like nutrients and pollution, we use an integrated modeling approach to study the potential accumulation and biomagnification. We describe the integrative modeling approach and the consecutive adaption of the AQUATOX model, used as modeling framework for ecological risk assessment. As a starting point, pre-calibrated simulations were adapted to Yangtze-specific conditions (regionalization). Two exemplary food webs were developed by a thorough review of the pertinent literature. The first typical for the flowing conditions of the original Yangtze River and the Daning River near the city of Wushan, and the second for the stagnant reservoir characteristics of the aforementioned region that is marked by an intermediate between lake and large river communities of aquatic organisms. In close cooperation with German and Chinese partners of the Yangtze-Hydro Research Association, other site-specific parameters were estimated. The MINIBAT project contributed to the calibration of physicochemical and bathymetric parameters, and the TRANSMIC project delivered hydrodynamic models for water volume and flow velocity conditions. The research questions were firstly focused on the definition of scenarios that could depict representative situations regarding food webs, pollution, and flow conditions in the TGR. The food webs and the abiotic site conditions in the main study area near the city of Wushan that determine the environmental preconditions for the organisms were defined. In our conceptual approach, we used the pesticide propanil as a model substance.     

Occurrence and distribution of heavy metals and tetracyclines in agricultural soils after typical land use change in east China

Land use in east China tends to change from paddy rice to vegetables or other high-value cash crops, resulting in high input rates of organic manures and increased risk of contamination with both heavy metals (HMs) and antibiotics. This investigation was conducted to determine the accumulation, distribution and risks of HMs and tetracyclines (TCs) in surface soils and profiles receiving different amounts of farmyard manure. Soil samples collected from suburbs of Hangzhou city, Zhejiang province were introduced to represent three types of land use change from paddy rice to asparagus production, vineyards and field mustard cultivation, and divided into two portions, one of which was air-dried and sieved through 2-, 0.3- and 0.149-mm nylon mesh for determination of pH and heavy metals. The other portion was frozen at ?20 °C, freeze-dried and sieved through a 0.3-mm nylon mesh for tetracyline determination. HM and TC concentrations in surface soils of 14-year-old mustard fields were the highest with total Cu, Zn, Cd and ∑TCs of 50.5, 196, 1.03 mg?kg^?1 and 22.9 μg?kg^?1, respectively, on average. The total Cu sequence was field mustard?>?vineyards?>?asparagus when duration of land use change was considered; oxytetracycline (OTC) and doxycycline were dominant in soils used for asparagus production; OTC was dominant in vineyards and chlortetracycline (CTC) was dominant in mustard soils. There were positive pollution relationships among Cu, Zn and ∑TCs, especially between Cu and Zn or Cu and ∑TCs. Repeated and excessive application of manures from intensive farming systems may produce combined contamination with HMs and TCs which were found in the top 20 cm of the arable soil profiles and also extended to 20–40 cm depth. Increasing manure application rate and cultivation time led to continuing increases in residue concentrations and movement down the soil profile.     

利用污泥熟肥作为高含水率污泥堆肥调理剂

采用静态强制通风好氧堆肥的方法,以木屑作为对比,考察了利用污泥熟肥作为调理剂对污泥堆肥过程的影响。结果表明,与以木屑作为调理剂的污泥堆体(对照组)相比,以污泥熟肥作为调理剂的污泥堆体(实验组)升温快,高温阶段(>50℃)持续时间长达10 d,满足粪便无害化卫生标准的要求,而对照组仅持续了2 d;实验组腐熟的堆肥含水率从60%降到39%,下降了21%,pH维持在7.5～8.5范围内,微生物活性较强,而对照组含水率仅下降15%,pH始终低于7.5;实验组种子发芽指数(GI)在第14天就回升到80%以上,基本上去除了植物毒性,而对照组GI在第22天才回升到50%。总体而言,污泥熟肥能显著改善堆肥中微生物的微环境,促进有机物的降解,缩短堆肥腐熟时间,是一种优质的调理剂。     

利用废弃物衍生燃料的热化学处理法制富含氢气合成气

为了探讨利用热化学方式从城市垃圾中制取富含氢气合成气过程的要素影响,解析氢气发生特性及其与主要影响要素之间的关系。在分析了城市生活垃圾组分特性的基础上,将其加工成组分均一的废弃物衍生燃料(refuse derived fuel,RDF),并在700、800和900℃等3个温度条件下,分别开展了RDF的热解、气化及水蒸汽气化等实验。研究表明,RDF的加工不但可有效降低垃圾含水率,还可将垃圾热值提高近1倍。温度和添加水蒸汽是从RDF中制取富含氢气合成气过程中的关键影响要素。其中,温度对氢气生成起到至关重要的决定作用,温度的提高对促进H2浓度的提高有利,同时,在气化过程中添加水蒸汽,可有效促进CO和H2等有价气体组分生成。在900℃的高温水蒸汽气化处理过程中,可获得H2浓度最高为34.13%的合成气。另外,800℃热解过程所产生的合成气热值最高,达到14 509 kJ/Nm3。     

Adsorption behavior of light green anionic dye using cationic surfactant-modified wheat straw in batch and column mode

An agricultural by-product, natural wheat straw (NWS), was soaked in 1 % cationic surfactant (hexadecylpyridinium bromide, CPB) solution for 24 h (at 293 K), and modified wheat straw (MWS) was obtained. Analysis of FTIR, XFR, and nitrogen element showed that CPB was adsorbed onto surface of NWS. Then, MWS was used as adsorbent for the removal of light green dye (LG, anionic dye) from aqueous solution. The experiment was performed in batch and column mode at room temperature (293 K). Sodium chloride (up to 0.1 mol/L) existed in solution was not favor of LG dye adsorption. The equilibrium data were better described by Langmuir isotherm, and adsorption capacity of q _m from Langmuir model was 70.01?±?3.39 mg/g. In fixed-bed column adsorption mode, the effects of initial LG concentration (30, 50, 70 mg/L) and flow rate (6.5, 9.0, 14.5 mL/min) on adsorption were presented. Thomas and modified dose–response models were used to predict the breakthrough curves using nonlinear analysis method, and both models can fit the breakthrough curves. Theoretical and experimental breakthrough curves were drawn and compared. The results implied that MWS can be used as adsorbent material to remove LG from aqueous solution.     

基于环境与经济发展协调度评价的生态镇建设探讨——以徐州市大沙河镇为例

随着人地关系的矛盾越来越突出,处理好经济发展与环境保护的关系,将两者高度融合,做到环境与经济的持续协调发展逐渐受到各方重视.以徐州市大沙河镇为例,在区域环境与经济发展协调度评价的基础上探索生态镇的建设模式.结果表明,2010年大沙河镇的环境综合发展指数为1.584,经济综合发展指数为1.182,环境与经济发展的协调度为0.88,处于良好协调状态.最后在评价结果的基础上分析了大沙河生态镇建设的模式.     

Bioaccessibility of polychlorinated biphenyls in workplace dust and its implication for risk assessment

Human exposure to bioaccessible PCBs via indoor dust is limited around the world. In the present study, the workplace dust sample from commercial office, hospital, secondary school, shopping mall, electronic factory and manufacturing plant were collected from Hong Kong for PCBs analyses. Total PCBs concentrations ranged from 46.8 to 249 ng g⁻¹, with a median of 107 ng g⁻¹. Manufacturing plant showed the highest concentration among all of sampling sites. PCB 77 was found as the dominant congeners. The bioaccessibility of PCBs in small intestinal juice ranging from 8.3% to 26.0% was significantly higher than that in gastric condition, ranging from 4.8% to 12.4%. In addition, significant negative correlations (p < 0.05) were observed between K_OW and bioaccessibility for all workplace dust samples. Risk assessment indicated that the averaged daily dose of dioxin-like PCBs via non-dietary intake of workplace dust, considering the bioaccessibility of PCBs, were much lower than the TDI of dioxins (2.3 pg WHO-TEQ kg bw⁻¹ d⁻¹) established by Joint FAO/WHO Expert Committee on Food Additives.