点源污染对三峡库区陆生植物群落的影响

三峡库区一些污染严重的工业企业是当地主要的点源污染源，对周围植物群落产生了巨大危害，而植物是生态系统赖以存在的基础，它的生长发育直接影响到生态系统的结构及其正常功能的实现。本研究按照与点源污染源的距离为梯度，通过在三峡库区兴山县白沙河磷化工厂周围布设了32个植物群落固定样地，并以点源污染无法影响到的植物群落为对照，进行样地的野外群落学调查;在每个样地取不同种植物叶片100克左右和样地0~20cm土壤500克，以石灰滤纸法同步进行大气氟化物的取样。样品带回室内应用氟离子选择电极法，测定大气氟化物含量、植物叶片氟的累积量和土壤水溶性氟的含量。同时在野外调查时使用PAM2100叶绿素荧光仪测定植物最大光化学效率即Fv/Fm的值。通过野外调查试验和相关的室内分析，研究了（1）：点源污染对三峡库区陆生植物群落组成和物种多样性的影响;（2）：点源污染中的主要污染物对植物及土壤环境的影响;（3）：不同物种叶片最大光化学效率Fv/Fm对污染胁迫响应的差异。结果如下： 点源污染对植物群落物种丰富度以及Pielou均匀度指数均有不同程度的影响，对于群落结构相对简单的马尾松林和柏木林的不利影响更为显著。相对于污染区来说，对照区中物种重要值的集中程度有所下降。许多物种的重要值在污染区与对照区有明显的变化。马尾松（Pinus massoniana）、檵木（Loropetalum chinense ）、铁仔（Myrsine africana）、卷柏（Selaginella tamariscina ）等对照区重要值较污染区为高，黄檀（Dalbergia hupeana ）、菱叶海桐（Pittosporum truncatum）、君迁子（Diospyros lotus）等污染区的重要值较对照区为高。群落中有些物种比如柏木（Cupressus funebris）的天然更新也受到污染的影响。 污染区土壤pH值大多低于对照区，但是与离污染源距离的相关性不强。污染区有些物种比如马尾松、柏木等叶片中的全氟含量与大气中氟化物的含量和土壤水溶性氟含量明显正相关。但是另外有些物种氟的累积量受点源污染的影响不显著，比如菱叶海桐、翅柃（Eurya alata）等在污染严重的样地内生存状况仍然很好。 在距离点源污染近的样地内，大多数物种的最大光化学效率Fv/Fm的值显著下降。栓皮栎（Quercus variabilis）、马尾松和柏木等的Fv/Fm值与距污染源的距离呈明显的正相关，都是随着离污染源越来越近而逐渐降低。根据污染区相对对照区Fv/Fm值下降幅度的不同，把植物划分为三种类型：对污染敏感型如柏木、铁仔、檵木等，中等敏感型如油桐（Vernicia fordii）、香叶树（Lindera communis）和不敏感型如山胡椒（Lindera glauca）和 蝴蝶花（Iris japonica）等。

The influence of topography and land use on water quality of Xiangxi River in Three Gorges Reservoir region

A self-organizing map (SOM) was used to cluster the water quality data of Xiangxi River in the Three Gorges Reservoir region. The results showed that 81 sampling sites could be divided into several groups representing different land use types. The forest dominated region had low concentrations of most nutrient variables except COD, whereas the agricultural region had high concentrations of NO3N, TN, Alkalinity, and Hardness. The sites downstream of an urban area were high in NH3N, NO2N, PO4P and TP. Redundancy analysis was used to identify the individual effects of topography and land use on river water quality. The results revealed that the watershed factors accounted for 61.7% variations of water quality in the Xiangxi River. Specifically, topographical characteristics explained 26.0% variations of water quality, land use explained 10.2%, and topography and land use together explained 25.5%. More than 50% of the variation in most water quality variables was explained by watershed characteristics. However, water quality variables which are strongly influenced by urban and industrial point source pollution (NH3N, NO2N, PO4P and TP) were not as well correlated with watershed characteristics.

Nutrient dynamics and the eutrophication of shallow lakes Kasumigaura (Japan), Donghu (PR China), and Okeechobee (USA)

We compared the nutrient dynamics of three lakes that have been heavily influenced by point and non-point source pollution and other human activities. The lakes, located in Japan (Lake Kasumigaura), People's Republic of China (Lake Donghu), and the USA (Lake Okeechobee), all are relatively large(>30 km(2)), very shallow (<4 m mean depth), and eutrophic. In all three lakes we found strong interactions among the sediments, water column, and human activities. Important processes affecting nutrient dynamics included nitrogen fixation, light limitation due to resuspended sediments, and intense grazing on algae by cultured fish. As a result of these complex interactions, simple empirical models developed to predict in-lake responses of total phosphorus and algal biomass to external nutrient loads must be used with caution. While published models may provide 'good' results, in terms of model output matching actual data, this may not be due to accurate representation of lake processes in the models. The variable nutrient dynamics that we observed among the three study lakes appears to be typical for shallow lake systems. This indicates that a greater reliance on lake-specific research may be required for effective management, and a lesser role of inter-lake generalization than is possible for deeper, dimictic lake systems. Furthermore, accurate predictions of management impacts in shallow eutrophic lakes may require the use of relatively complex deterministic modeling tools. (C) 2000 Elsevier Science Ltd. All rights reserved.

近地表土壤水分条件对坡面农业非点源污染物运移的影响

采用人工模拟降雨实验,研究了近地表土壤水分条件,尤其是土壤水分饱和条件对土壤侵蚀过程中农业非点源污染物运移的影响.结果表明,前期近地表土壤水分条件对土壤侵蚀过程中农业非点源污染物的迁移有着很大影响.饱和含水量时径流及泥沙中非点源污染物的流失浓度和流失量大于非饱和含水量,且前期近地表土壤含水量越大,径流及泥沙中农业非点源污染物的流失浓度和流失量越大.土壤氮素的主要流失途径是降雨所产生的径流,约占总流失量的90.4%～99.8%;土壤磷素的流失途径是降雨径流和侵蚀产沙,分别占总流失量的2.67%～23.5%和76.5%～97.3%.同时,土壤质地对磷素养分的流失有很大影响,杨凌土随泥沙流失的DP浓度和流失量均大于安塞黄绵土.最后,提出了采取最佳管理措施等控制农业非点源污染的针对性建议.

分布式水文模型的误差分析

分布式水文模型以其具有明确物理意义的参数结构和对空间分异性的全面反映,能够准确详尽地描述和模拟流域内真实的降水径流过程而被广泛需求和关注。在模拟土地利用、土地覆盖、水土流失等各种变化过程的水文响应,面源污染、陆面过程、气候变化影响评价等诸多领域都有广泛的应用。模型的预报精度和误差至关重要,决定了模型的应用和推广。在分析分布式水文模型建立和验证过程的基础上,提出了模型的4类误差来源:被排除在外的因素引起的误差,实测历史记录资料的随机或系统误差,参数误差和模型结构误差,讨论了各类误差的分析与计算方法,为模型的发展和成长提供了依据。

亚硝化—厌氧氨氧化处理猪场废水研究

猪场废水COD浓度高、氨氮浓度高、悬浮物浓度高，已成为农村面源污染的主要来源，并严重威胁到农村饮用水安全。猪场废水氨氮浓度高、处理难度大，如何采用经济高效的方法，去除氨氮使其达到排放标准，一直是猪场废水处理中面临的重要难题。 厌氧氨氧化是近年受到国内外水处理研究者广泛关注的新型生物脱氮技术，具有不需要外加有机碳源、节省供氧量、降低能耗等优点。虽然国内外研究者对厌氧氨氧化过程的脱氮机理、厌氧氨氧化菌的生理生化特性等进行了多方面的研究，但已有的报道大多以模拟废水为研究对象，以猪场废水为研究对象的报道，在国内外文献中极少有报导。 本论文以猪场废水为主要研究对象，考察了猪场废水的亚硝化过程、厌氧氨氧化的启动过程，并对亚硝化和厌氧氨氧化联合用于猪场废水脱氮进行了探索。 1．论文首先研究了猪场废水的亚硝化过程，考察了废水水质和主要运行条件对亚硝化过程的影响。实验表明：（1）亚硝化阶段反应时间为8到10h时，出水中氨氮和亚硝酸盐浓度比可达到1：1～1：1.23，满足厌氧氨氧化反应对二者比例的要求；达到前述要求时，氨氮去除率达到58.3～65.6 %，亚硝化率在整个过程均保持在97 %以上，COD去除率在59.2～68.6 %；（2）曝气量（溶解氧）对亚硝化过程影响显著，随着曝气量增大，达到厌氧氨氧化要求的氨氮与亚硝酸盐氮浓度比例所需水力停留时间τ越短，pH出现明显下降的时间越短；（3）τ对应的pH在7.8～8.1之间，无需进行pH调节即可满足厌氧氨氧化反应对pH的要求；（4）氨氮和COD降解过程遵循一级反应动力学，氨氮和COD降解的速率常数分别为0.0656～0.0724 1/h和0.0491～0.0664 1/h。 2．在进行亚硝化过程研究的同时，以模拟废水为试验对象，进行厌氧氨氧化启动研究。以反硝化污泥和养殖厂储水池厌氧底泥的混合污泥作为接种污泥，历时大约100天，培育出具有厌氧氨氧化活性的污泥，氨氮和亚硝酸盐氮最高进水浓度分别为223.8 mg/L和171.4 mg/L，去除率最高分别达48%和41.5%，此时二者消耗比例为1.33：1。 3．在猪场废水的亚硝化研究完成和厌氧氨氧化过程初步启动成功后，在模拟废水中逐步加入猪场废水的亚硝化处理出水，逐步实现亚硝化和厌氧氨氧化的组合。亚硝化出水添加到厌氧反应器后，厌氧氨氧化反应仍可继续进行，且去除效率逐步提高。研究发现添加的亚硝化出水中携带的亚硝化细菌在厌氧氨氧化菌膜外层生长并累积，增加了厌氧氨氧化反应基质的传质阻力，妨碍了厌氧氨氧化效率的提高。 4．亚硝化－厌氧氨氧化实际工程应用探索中，生物接触氧化池可在有效去除废水中的有机物的同时实现亚硝化，出水中氨氮和亚硝酸盐比例平均为1.10，可满足后续厌氧氨氧化的要求；在适宜的进水浓度和温度下，ABR池出现了厌氧氨氧化启动的迹象；研究同时发现，水质的波动和气温的变化是工程中影响厌氧氨氧化菌活性的重要因素。 论文的主要创新点在于：（1）以猪场废水为研究对象，以实现厌氧氨氧化为目标，对亚硝化过程进行了比较详细的考察，获得了亚硝化出水满足厌氧氨氧化要求的工艺条件，通过对其COD和氨氮降解过程的考察，得出亚硝化阶段COD降解和氨氮去除的动力学模型；（2）对亚硝化－厌氧氨氧化处理猪场废水进行了探索，确立了影响其污染物去除率稳定的重要因素。 论文的上述研究成果，为厌氧氨氧化技术的实用性研究提供理论依据。 Piggery wastewater, which is characterized by high concentration of COD、ammonium and suspend substance, has become a most important source of non-point source pollution and also severely threats drinking water security in rural area. How to discharge piggery wastewater with the ammonium concentration meeting standard by economical and effective method? This is the most urgent problem in piggery wastewater treatment. As a new biological nitrogen removal technology, Anammox process has been paid more and more attention by researchers all over the world. Anammox has advantages of no need of organic carbon addition, low oxygen consumption and energy consumption. Plenty of investigations have been carried out to the mechanism, physiological and biochemical characteristic of bacteria about Anammox. Most of researches focused on synthetic wastewater, there is rare report about its application in piggery wastewater. In this paper，experimental studies were performed to investigate Sharon process in treatment of piggery wastewater，the start up process of Annammox using synthetic wastewater were studied, the feasibility of applying Sharon-Anammox process in the nitrogen removal of piggery wastewater was evaluated. 1. Sharon process of piggery wastewater was firstly investigated to analyze the effects of water quality and main running parameters, which meet the NH4+-N to NO2--N ratio requirement of successive Anammox. Results showed: (1)During Sharon Process，after 8～10 hours’ reaction the NH4+-N to NO2--N ratio in effluent reached 1:1.0～1:1.23, when the removal percentage of NH4+-N was 58.3～65.6 %, a semi-nitration rate of above 97 % was achieved during the process; meanwhile 59.2～68.6 % of the COD was also removed. (2)The aeration rate（oxygen） had obvious effect on the hydraulic retention time(τ) which met the NH4+-N to NO2--N ratio requirement of Anammox. As aeration rate increased, the hydraulic retention time(τ) was shortened. (3) The pH corresponding to τ was between 7.8 and 8.1, thus it needed no artificial adjustment. (4) The reduction of ammonia and COD followed the first-order reaction kinetics. The velocity constants of ammonia and COD were 0.0656～0.0724 1/h and 0.0491～0.0664 1/h, respectively. 2. The startup of Anammox process using the artificial wastewater was performed simultaneously with Sharon. The aim was to investigate the running parameters of Anammox and make foundation for the combination stage. By using the mixture of denitrifying sludge and anaerobic sludge in tank of the breeding factory, sludge of Anammox activity was cultivated in UASB after 100 days. The removal percentage of NH4+-N and NO2-N were up to 48% and 41.5%, respectively, when the NH4+-N and NO2-N influent concentration were 223.8 mg/L and 171.4 mg/L, respectively, the NH4+-N and NO2-N removal rate was 1.33:1. 3. After investigation of Sharon and startup of Anammox, effluent of Sharon process was added into the synthetic wastewater to combine Sharon and Anammox step by step. It took some time after the addition of Sharon effluent that Anammox reaction continued and the removal rate kept increasing. It indicated that nitrifying bacteria were carried by the Sharon effluent cumulated in the outer layer of Anammox. This enhanced transfer resistance of Anammox reaction and the increasing removal rate was restrained. 4. In the bio-contact oxidation pond of practical project, Sharon process were carried out successfully and organic compounds were removed effectively. An average NO2-N/ NH4+-N rate of 1:1.0 was achieved in the effluent, which met the requirement of successive Anammox. Under condition of suitable influent concentration and temperature, there was evidence that Anammox could start up in ABR. The variety of wastewater and temperature had great affects on Anammox activity in practical engineering. Innovation of this paper: (1) The Sharon process for treating piggery wastewater was discussed in details. Technological parameters that met requirement of Anammox were obtained. The dynamic models of COD and ammonium removal in the process were educed. (2) Sharon-Ananmmox for treatment of piggery wastewater was investigated, and the primary influencing factors was studied. This paper could be a theoretical consult for research of Anammox utility.

黄土高原淤地坝土壤性质剖面变化规律及其功能探讨

为分析淤地坝土壤性质的剖面变化规律及其在非点源污染工程治理方面的可能性,采用经典统计学方法研究了黄土高原典型淤地坝土壤性质在5.20 m剖面上的变化规律,并探讨了淤地坝作为碳储存库以及养分富集库的独特功能.结果表明,①坝前土壤剖面容重、砂粒含量低于坝尾,而土壤含水率、有机碳、粘粒、粉粒、速效磷、硝态氮以及铵态氮均大于坝尾;容重随剖面的变异情况为弱变异性,其余指标为中等变异性;除坝前砂粒含量和坝尾土壤含水率外,其余指标均呈正态分布;②坝前和坝尾剖面土壤含水率随土层深度的增加均呈锯齿型变化趋势,在剖面上的分布表现为波动型;土壤有机碳、速效磷、铵态氮随剖面的变化规律与土壤水分的趋势相同;③除坝尾容重与硝态氮、铵态氮及速效磷与铵态氮的相关性未达到显著水平外,土壤含水率、有机碳、容重、粘粒、粉粒、砂粒、速效磷、硝态氮以及铵态氮之间的相关性均达到了显著水平(p<0.05),并且坝前与坝尾剖面土壤各个性质之间所表现的正相关性或负相关性是一致的;④淤地坝作为黄土高原的一个重要碳储存库,坝前有机碳储量高于坝尾,且坝前在400~520 cm储量最高,坝尾在0~100 cm储量最高;⑤淤地坝对速效养分具有富集效应,坝前储量大于坝尾...

Land use and water quality response in the northern region of Changxing County

In this paper, taking the northern region of Changxing County for example, with ammonia nitrogen as a pollution assessment index, we used an improved export coefficient method for estimate polluting load of non-point source pollution (NSP) and the social pollution survey data in the study area to estimate point source pollution. By comparing the total pollution output and the national surface water environmental quality standards find that the whole study area achieves the second water quality standard. However, Jiapu Township exceeds the water quality standards seriously because of the superfluous point source pollution. The water quality of other Townships is good. Further analysis showed that different types of land use and proportions in the northern region of Changxing County have a significant impact on the non-point source pollution, the general law is farmland contributes the largest share of the non-point source pollution output, followed by residential area and bare land, besides, with the increase in the proportion of forest and the decrease of farmland and residential area, the non-point source pollution reduces gradually. © 2010 IEEE.

A QUANTITATIVE ASSESSMENT OF SOURCE CONTRIBUTIONS TO INHALABLE PARTICULATE MATTER POLLUTION IN METROPOLITAN BOSTON

In this paper, source apportionment techniques are employed to identify and quantify the major particle pollution source classes affecting a monitoring site in metropolitan Boston, MA. A Principal Component Analysis (PCA) of paniculate elemental data allows the estimation of mass contributions for five fine mass panicle source classes (soil, motor vehicle, coal related, oil and salt aerosols), and six coarse panicle source classes (soil, motor vehicle, refuse incineration, residual oil, salt and sulfate aerosols). Also derived are the elemental characteristics of those source aerosols and their contributions to the total recorded elemental concentrations (i.e. an elemental mass balance). These are estimated by applying a new approach to apportioning mass among various PCA source components: the calculation of Absolute Principal Component Scores, and the subsequent regression of daily mass and elemental concentrations on these scores.

Carbon source/sink function of a subtropical, eutrophic lake determined from an overall mass balance and a gas exchange and carbon burial balance

Although studies on carbon burial in lake sediments have shown that lakes are disproportionately important carbon sinks, many studies on gaseous carbon exchange across the water-air interface have demonstrated that lakes are supersaturated with CO2 and CH4 causing a net release of CO2 and CH4 to the atmosphere. In order to more accurately estimate the net carbon source/sink function of lake ecosystems, a more comprehensive carbon budget is needed, especially for gaseous carbon exchange across the water-air interface. Using two methods, overall mass balance and gas exchange and carbon burial balance, we assessed the carbon source/sink function of Lake Donghu, a subtropical, eutrophic take, from April 2003 to March 2004. With the overall mass balance calculations, total carbon input was 14 905 t, total carbon output was 4950 1, and net carbon budget was +9955 t, suggesting that Lake Donghu was a great carbon sink. For the gas exchange and carbon burial balance, gaseous carbon (CO2 and CH4) emission across the water-air interface totaled 752 t while carbon burial in the lake sediment was 9477 t. The ratio of carbon emission into the atmosphere to carbon burial into the sediment was only 0.08. This low ratio indicates that Lake Donghu is a great carbon sink. Results showed good agreement between the two methods with both showing Lake Donghu to be a great carbon sink. This results from the high primary production of Lake Donghu, substantive allochthonous carbon inputs and intensive anthropogenic activity. Gaseous carbon emission accounted for about 15% of the total carbon output, indicating that the total output would be underestimated without including gaseous carbon exchange. (C) 2007 Elsevier Ltd. All rights reserved.

Heavy metal pollution in China: Origin, pattern and control

Goal, Scope and Background. Heavy metal is among one of the pollutants, which cause severe threats to humans and the environment in China. The aim of the present review is to make information on the source of heavy metal pollution, distribution of heavy metals in the environment, and measures of pollution control accessible internationally, which are mostly published in Chinese. Methods. Information from scientific journals, university journals and governmental releases are compiled focusing mainly on Cd, Cu, Pb and Zn. Partly Al, As, Cr, Fe, Hg, Mn and Ni are included also in part as well. Results and Discussion. In soil, the average contents of Cd, Cu, Pb and Zn are 0.097, 22.6, 26.0 and 74.2 mg/kg, respectively. In the water of. the Yangtze River Basin, the concentrations of Cd, Cu, Pb and Zn are 0.080, 7.91, 15.7 and 18.7 pg/L, respectively. In reference to human activities, the heavy metal pollution comes from three sources: industrial emission, wastewater and solid waste. The environment such as soil, water and air were polluted by heavy metals in some cases. The contents of Cd, Cu, Pb and Zn even reach 3.16, 99.3, 84.1 and 147 mg/kg, respectively, in the soils of a wastewater irrigation zone. These contaminants pollute drinking water and food, and threaten human health. Some diseases resulting from pollution of geological and environmental origin, were observed with long-term and non-reversible effects. Conclusions. In China, the geological background level of heavy metal is low, but with the activity of humans, soil, water, air, and plants are polluted by heavy metals in some cases and even affect human health through the food chain. Recommendations and Outlook. To remediate and improve environmental quality is a long strategy for the polluted area to keep humans and animals healthy. Phytoremediation would be an effective technique to remediate the heavy metal pollutions.

The distribution, enrichment and source of potential harmful elements in surface sediments of Bohai Bay, North China

A geochemical study of Bohai Bay surface sediments was carried out to analyze the potential harmful element (PHE: Ge, Mo, In, Sn, Sb,Te, Tl, Bi and V) concentrations, transportation and deposition, enrichment factors and sources. Germanium, Mo, In, Sn, Sb, Te, Tl, Bi and V concentrations in the surface sediments were: 1.43-1.71, 0.52-1.43, 0.04-0.12, 2.77-4.14, 1.14-2.29, 0.027-0.085, 0.506-0.770, 0.27-0.63 and 70.35-115.90 mu g/g, respectively. The distributions of total PHE concentrations, together with sequential extraction analyses, showed that the PHEs were mainly due to natural inputs from the continental weathering delivered to the bay by rivers and atmospheric transportation and deposition. However, high Mo, Sb, Te, Bi and V occurred in non-residual fractions, suggesting some anthropogenic inputs in addition to the natural inputs. Besides sources, the distributions of PHEs were influenced by the coupling of physical, chemical and biological processes. Enrichment factor (EF) was computed for each site for each element in order to assess the polluting elements and the degree of pollution at each site. Results revealed that the EFs were generally lower than 1.0, particularly for Ge, Mo, In, Sn, Tl and V; however, the EFs were higher (>1.5), particularly for Sb, Te and Bi, revealing moderate contamination. (C) 2010 Elsevier B.V. All rights reserved.

Two-dimensional simulation of an electron cyclotron resonance plasma source with self-consistent power deposition

Using a refined two-dimensional hybrid-model with self-consistent microwave absorption, we have investigated the change of plasma parameters such as plasma density and ionization rate with the operating conditions. The dependence of the ion current density and ion energy and angle distribution function at the substrate surface vs. the radial position, pressure and microwave power were discussed. Results of our simulation can be compared qualitatively with many experimental measurements.