Synthesis of carbon-coated magnetic nanocomposite (Fe3O4@C) and its application for sulfonamide antibiotics removal from water

The occurrence of antibiotics in the environment has recently raised serious concerns regarding their potential threat to human health and aquatic ecosystem. A new magnetic nanocomposite, Fe304@C （Fe304 coated with carbon）, was synthesized, characterized, and then applied to remove five commonly-used sulfonamides （SAs） from water. Due to its combinational merits of the outer functionalized carbon shell and the inner magnetite core, Fe3O4@C exhibited a high adsorption affinity for selected SAs and a fast magnetic separability. The adsorption kinetics of SAs on Fe304 @ C could be expressed by the pseudo second-order model. The adsorption isotherms were fitted well with the Dual-mode model, revealing that the adsorption process consisted of an initial partitioning stage and a subsequent hole-filling stage. Solution pH exerted a strong impact on the adsorption process with the maximum removal efficiencies （74% to 96%） obtained at pH 4.8 for all selected SAs. Electrostatic force and hydrogen bonding were two major driving forces for adsorption, and electron-donor-acceptor interactions may also make a certain contribution. Because the synthesized Fe304@C showed comprehensive advantages of high adsorptivity, fast magnetic separability, and prominent reusability, it has potential applications in water treatment.     

Radiative dryness index and potential productivity of vegetation in China

The Chikugo Model is used to estimate radiative dryness indexes (RDI) and net primary productivity (NPP) of vegetation zones in China by calculating cli-matic parameters. That provides the water-heat equilibrium condition, potential primary production for natural vegetation in various vegetation zones, and their geographical distribution pattern. That could be used as the basis for study the effect of global climate change on ecosystems.     

黄海和东海海域溶解氧的分布特征

根据黄河和东海海区四个季度的调查资料，描述了溶解氧的时空分布和变化规律。黄、东海溶解氧分布的基本特征是北高南低，西高东低，随着水温的变化，不同季节这一差别有所不同。黄、东海溶解氧平均值分别为495．4和420．3μmol/L，测定范围分别为90．2－681．9和133－9－692．8μmol/L。以长江口以东H断面为例，描述了夏季溶解氧的断面分布特征，在20－30m水层出现一氧跃层，30m以下垂直分布比较均匀。文中还深入研究了东海陆架区黑潮水溶解氧的分布特征和变化规律。     

水生态系中有机磷农药生物净化机理的研究

本报告研究了利用氧化塘处理废水中对硫磷农药的生物净化机理。分离出Pseudomonas sp.CTP-01、CTP-02两个菌株,对对硫磷和对硝基酚具有很高的降解能力,其降解速度分别为11.0g/l/day和6.0g/I/day。观察了对硫磷及分解产物对栅藻光合作用的影响和模拟藻菌系统中对硝基酚的降解。研究了Pseudomonas sp.CTP-01的对硫磷的酶解,对硫磷水解酶降解对硫磷的最高速度可达1×10~4n mol/mg prot./min.Cu离子对酶有明显的激活作用。Pseudomonas sp.CTP-02在降解对硝基酚时首先发生硝基脱落,然后进一步被降解。     

用生态文明的观点浅析盘锦市的发展

盘锦市的发展应以生态发展为基点,正确对待已存在的环境问题,明确发展方向,加强对国家级保护区和天然湿地的保护,要以环境优化经济增长。     

广西土壤和沉积物砷含量及污染分布特征

广西素有“有色金属之乡”美誉,土壤重金属污染问题较为突出。通过总结1989年以来相关文献,探讨了广西土壤和沉积物中砷含量及污染分布特征。3 045个和477个土壤和沉积物有效样点的统计分析表明,广西砷污染土壤主要分布于桂西北地区,尤其是刁江及金城江流域;矿业活动显著影响土壤砷积累,从其均值看：工矿区非农用土壤（140.5 mg/kg）>工矿区农用土壤（80.68 mg/kg）>非工矿区农用土壤（19.11 mg/kg）>城区土壤（18.35 mg/kg）,重度砷污染农用地样本均来自南丹;工矿区河流沉积物砷含量（283.5 mg/kg）远高于非工矿区,主要受影响区分布在刁江及大环江流域。为了控制环境风险,建议开展主要水系沉积物砷污染详查,加强南丹及周边区域污染防控和污染土壤修复。     

Towards a better hydraulic cleaning strategy for ultrafiltration membrane fouling by humic acid: Effect of backwash water composition

As a routine measurement to alleviate membrane fouling, hydraulic cleaning is of great significance for the steady operation of ultrafiltration (UF) systems in water treatment processes. In this work, a comparative study was performed to investigate the effects of the composition of backwash water on the hydraulic cleaning performance of UF membranes fouled by humic acid (HA). Various types of backwash water, including UF permeate, Milli-Q water, NaCl solution, CaCl₂ solution and HA solution, were compared in terms of hydraulically irreversible fouling index, total surface tension and residual HA. The results indicated that Milli-Q water backwash was superior to UF permeate backwash in cleaning HA-fouled membranes, and the backwash water containing Na⁺ or HA outperformed Milli-Q water in alleviating HA fouling. On the contrary, the presence of Ca^2 + in backwash water significantly decreased the backwash efficiency. Moreover, Ca^2 + played an important role in foulant removal, and the residual HA content closely related to the residual Ca^2 + content. Mechanism analysis suggested that the backwash process may involve fouling layer swelling, ion exchange, electric double layer release and competitive complexation. Ion exchange and competitive complexation played significant roles in the efficient hydraulic cleaning associated with Na⁺ and HA, respectively.     

A Pilot Study on Using Urinary 1-Hydroxypyrene Biomarker for Exposure to PAHs in Beijing

To study whether the urinary 1-hydroxypyrene (1-OHP) could be the biomarker of atmospheric PAHs, a small-scale pilot study was carried out on the relation of 1-OHP vs PAHs with the traffic policemen in Beijing of smokers and nonsmokers to be subgroups in both the exposure and control groups. Both the PAHs and 1-OHP were analyzed with high performance liquid chromatography (HPLC). The ambient concentrations of PAHs were different at the different sites (the average sum of PAHs (TPAH) were 12.36, 16.27, 18.37 ng/m³ at the suburban residential, police station and high traffic area, respectively.), but considerably lower than the personal-exposure concentrations (the average TPAH were 65.84 and 47.28 ng/m³ for patrol cars and inspection station, respectively). Pyrene was correlated well with BaP and the summed PAHs (TPAH), with the correlation coefficients (R) of 0.79, 0.87 for ambient level and 0.92, 0.96 for personal exposure, respectively. The average of 1-hydroxypyrene of smokers and nonsmokers were 0.39, 0.15 μmol/mol creatinine in control group and 0.57, 0.33 μmol/mol creatinine in exposure group, respectively. The better correlation of pyrene to BaP and TPAH especially for personal exposure samples indicated that the probability of urinary 1-hydroxypyrene, the metabolite of pyrene, to be the biomarker of total PAH. Nonsmokers in the exposure and control groups had indistinguishable levels of 1-OHP, presumably because the ambient levels of pyrene were so similar (the average were 3.25, 3.20 ng/m³ at the police station and high traffic area, respectively.). Smokers in the control group had significantly higher 1-OHP than that of the nonsmokers, but showed indistinguishable differences in the exposure group. These results suggested that urinary 1-OHP could be a biomarker of PAHs only when the level of PAHs was at a relatively higher level. Smoking as an important influencing factor need to be controlled carefully.     

南京市大气CO2浓度模拟及源贡献研究

定量研究城市区域人为CO_2通量对于控制温室气体排放具有重要意义,而基于大气CO_2浓度观测与大气传输模型方法反演区域尺度的CO_2通量是未来的一个重要发展方向,其中模型对大气CO_2浓度的模拟则是能否成功反演CO_2通量的重要基础,然而我国还未有针对城市区域CO_2浓度的长时间(1年)模拟.本研究基于高空间分辨率的人为源CO_2资料与拉格朗日大气传输模型(WRF-STILT),对南京市郊区34 m观测高度处2014年大气CO_2浓度进行模拟,并就模型模拟结果的主要影响因素和源贡献组成进行了分析,研究得出以下结论:(1)WRF-STILT模型能较好模拟出4个季节观测到的高CO_2浓度及有季节差异性的日变化特征.(2)观测CO_2浓度的足迹贡献源区(footprint)的季节变化在盛行风向影响下差异巨大,CO_2浓度增加值在前1 d的主要贡献占据总浓度贡献的90%,表明该34 m高度观测点可代表长三角区域的CO_2排放量的影响,而安徽东部和江苏中南部对其影响更大;(3)相对于排放源的日变化,边界层高度等气象因素的差异是引起CO_2强日变化的主要因素,这也是模拟的各季度浓度增加值差异的原因,其中秋季(34.97μmol·mol-1)冬季(30.07μmol·mol-1)夏季(27.28μmol·mol-1)春季(23.36μmol·mol-1);(4)浓度的主要贡献来源分别为石油生产(41%)和能源工业(26%),这和长三角区域的人为源CO_2排放通量差异巨大(石油生产:3%,能源工业:35%).     

Roofing as a source of nonpoint water pollution

Sixteen wooden structures with two roofs each were installed to study runoff quality for four commonly used roofing materials (wood shingle, composition shingle, painted aluminum, and galvanized iron) at Nacogdoches, Texas. Each roof, either facing NW or SE, was 1.22 m wide x 3.66 m long with a 25.8% roof slope. Thus, there were 32 alternatively arranged roofs, consisting of four roof types x two aspects x four replicates, in the study. Runoff from the roofs was collected through galvanized gutters, downspouts, and splitters. The roof runoff was compared to rainwater collected by a wet/dry acid rain collector for the concentrations of eight water quality variables, i.e. Cu(2+), Mn(2+), Pb(2+), Zn(2+), Mg(2+), Al(3+), EC and pH. Based on 31 storms collected between October 1997 and December 1998, the results showed: (1) concentrations of pH, Cu, and Zn in rainwater already exceed the EPA freshwater quality standards even without pollutant inputs from roofs, (2) Zn and Cu, the two most serious pollutants in roof runoff, exceeded the EPA national freshwater water quality standards in virtually 100% and more than 60% of the samples, respectively, (3) pH, EC, and Zn were the only three variables significantly affected by roofing materials, (4) differences in Zn concentrations were significant among all roof types and between all roof runoff and rainwater samples, (5) although there were no differences in Cu concentrations among all roof types and between roof runoff and rainwater, all means and medians of runoff and rainwater exceeded the national water quality standards, (6) water quality from wood shingles was the worst among the roof types studied, and (7) although SE is the most frequent and NW the least frequent direction for incoming storms, only EC, Mg, Mn, and Zn in wood shingle runoff from the SE were significantly higher than those from the NW; the two aspects affected no other elements in runoff from the other three roof types. Also, Zn concentrations from new wood-shingle roofs were significantly higher than those from aged roofs of a previous study. The study demonstrated that roofs could be a serious source of nonpoint water pollution. Since Zn is the most serious water pollutant and wood shingle is the worst of the four roof types, using less compounds and materials associated with Zn along with good care and maintenance of roofs are critical in reducing Zn pollution in roof runoff.