长三角典型村域次降雨条件下氮素非点源输出特征

研究长三角典型都市农业村镇不同土地利用下的氮素非点源输出特征,以期为治理该区域的面源污染提供科学依据.通过典型次降雨径流事件中氮形态和输出负荷变化的研究发现:监测点总氮(TN)的事件平均浓度(EMC)为20.01～22.83mg/L,其中溶解态氮(DN)占TN的比例最大;研究区非点源氮流失以溶解态为主,DN又以溶解态有机氮(DON)为主.耦合各形态氮浓度与径流量特征,发现非点源氮素输出呈现2个峰值,且出现在径流峰值之前4～55min;TN、DN和硝态氮(NO3--N)浓度随降雨时间增加呈现减少趋势;氮素负荷受其浓度和径流量的共同作用,基本上呈现与氮素浓度相同的变化特征,但起伏变化较为平缓.氮素污染负荷积累曲线分析表明,村域地表径流各形态氮素均存在初期冲刷效应.     

Impact of dredging in a shallow coastal lagoon: Microtox Basic Solid-Phase Test, trace metals and Corophium bioassay

The aim of this work was to measure survival of the amphipod Corophium insidiosum and luminescence inhibition in the marine bacterium Vibrio fisheri on surface sediment samples collected from a shallow coastal lagoon (Pialassa Baiona, northern Adriatic Italian coast) before execution of dredging operations to deepen the main inner channel of the lagoon and restore the water circulation. Trace metal (Cd, Cu, Cr, Hg, Ni, Pb) concentrations, grain size and organic carbon matter content as loss of ignition were also measured. Toxicity testing with V. fisheri was carried out according to the Microtox Basic Solid-Phase Test (BSPT) protocol. The preliminary outcomes of this work show that: (a) the investigated area can be categorised as moderately degraded; (b) there is no evident spatial pattern in sediment toxicity and trace metal concentrations; (c) Microtox responses are not biased by sediment characteristics such as silt, clay and organic matter content.     

Cladocerans under conditions of small river damming by man and beavers

In beaver ponds, the species diversity, abundance, biomass, and production of cladocerans and the amount of food consumed by them have increased and the composition of dominant species has changed as compared to those in the stretches of small rivers with running water or dammed by man. The stimulating effect of water from a beaver pond has been confirmed in laboratory experiments. The average number of juvenile Ceriodaphnia affinis produced by one female was considerably greater in this water than in the water from flowing and dammed (by man) river stretches.     

钢铁行业大气环境影响评价方法与建议

按钢铁行业大气环评报告书的结构和顺序,结合HJ 2.2-2008《环境影响评价技术导则大气环境》中的相关技术要求,从评价因子、源强、评价等级、大气监测、大气预测、防护距离等方面出发,分析了钢铁行业大气环评中的评价等级确定、大气监测、大气预测等工作中存在的问题,并提出解决方案和建议对策。     

一体化接触氧化反应器处理景区生活污水

常州某旅游景区采用一体化生活污水处理装置处理该区生活污水,通过试验确定反应器的最佳工艺参数,研究表明采用接触氧化反应器处理农村污水,在反应器内溶解氧维持在2.0~4.0 mg/L,水力负荷为3.53 m3/(m3.d)的运行条件下,对COD、NH3-N及TN去除率分别达80.82%、69.12%、63.16%,出水可稳定达GB18918-2002《城镇污水处理厂污染物排放标准》一级标准。     

无机-有机复合絮凝剂PST处理印染废水效果研究

以模拟印染废水和实际印染废水为实验对象,检验了一种新合成有机-无机复合絮凝剂(PST)的絮凝效果。结果表明,PST具有良好的絮凝性能。在受试条件下,絮凝效果与絮凝剂投加量、染料浓度有较大相关性。废水的pH值应用范围较宽;搅拌时间对COD去除率和脱色率没有显著影响。采用PST处理广东省高明市某印染厂的印染废水后,COD去除率为75.16%,脱色率为76.18%,处理效果良好,处理成本明显低于目前市场上普遍使用的聚铝等絮凝剂。     

四川某中小城镇污水处理厂进水水质统计分析

生活污水水质对处理工艺的选择、设计参数的选取以及稳定运行十分重要。运用SPSS软件,对四川某中小城镇污水处理厂为期一年的进水指标(水量、COD、氨氮、总磷、pH、SS)进行方差和相关性分析。方差分析结果显示进水量、氨氮和SS在月份和季节之间存在显著性差异,而总磷和pH仅在月份之间存在显著差异,COD在季度和月份之间无显著性差异;指标相关性分析表明,进水量和氨氮之间呈负相关,氨氮和总磷、COD和总磷之间呈正相关,且相关性显著。在此分析的基础上对污水处理厂设计、工艺选择及运行管理提出了一些建议。     

Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

Toxicities were assessed for a pyrethroid (cypermethrin) and an organophosphate insecticide (chlorpyrifos) individually and in combination. A series of tests were conducted on di erent responses (acute, chronic, behavioral) of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant e ect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.     

Mobilities and leachabilities of heavy metals in sludge with humus soil

Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and residual forms (F5). For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28 days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8).     

Potential particulate pollution derived from UV-induced degradation of odorous dimethyl sulfide

UV-induced degradation of odorous dimethyl sulfide (DMS) was carried out in a static White cell chamber with UV irradiation. The combination of in situ Fourier transform infrared (FT-IR) spectrometer, gas chromatograph-mass spectrometer (GC-MS), wide-range particle spectrometer (WPS) technique, filter sampling and ion chromatographic (IC) analysis was used to monitor the gaseous and potential particulate products. During 240 min of UV irradiation, the degradation e ciency of DMS attained 20.9%, and partially oxidized sulfur-containing gaseous products, such as sulfur dioxide (SO2), carbonyl sulfide (OCS), dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2) and dimethyl disulfide (DMDS) were identified by in situ FT-IR and GC-MS analysis, respectively. Accompanying with the oxidation of DMS, suspended particles were directly detected to be formed by WPS techniques. These particles were measured mainly in the size range of accumulation mode, and increased their count median diameter throughout the whole removal process. IC analysis of the filter samples revealed that methanesulfonic acid (MSA), sulfuric acid (H2SO4) and other unidentified chemicals accounted for the major non-refractory compositions of these particles. Based on products analysis and possible intermediates formed, the degradation pathways of DMS were proposed as the combination of the O(1D)- and the OH- initiated oxidation mechanisms. A plausible formation mechanism of the suspended particles was also analyzed. It is concluded that UV-induced degradation of odorous DMS is potentially a source of particulate pollutants in the atmosphere.