低温条件下BAF+SPD组合工艺对滇池入湖河水的脱氮效果

为缓解湖泊富营养化问题，需进一步降低入湖河流氮的含量。针对滇池流域新运粮河的低C/N水质特征，研究了冬季低温条件下的微曝气生物滤池（BAF）及固相反硝化（SPD）组合异位脱氮工艺。结果表明，BAF+SPD组合工艺启动挂膜阶段，约3周后，NH₄⁺-N的去除率达80%以上，而反硝化细菌增殖相对缓慢，约5周后，NO₃^--N的去除率达80%以上；稳定运行的低温阶段，除降雨时间外，NH₄⁺-N平均去除率达80%，出水NH₄⁺-N浓度<1 mg/L；NO₃^--N平均去除率达到85%以上，出水NO₃^--N浓度<1 mg/L；TN平均去除率达80%以上，出水TN浓度<2 mg/L，主要水质指标达到国家地表水Ⅴ类标准。     

UASB反应器厌氧氨氧化菌的脱氮特性研究

研究UASB厌氧氨氧化（ANAMMOX）反应器运行情况，采用普通城市污水厂活性污泥接种，人工合成废水，pH值在7.4～7.8之间，温度控制在(32±1)℃。在反应器稳定运行270～450 d之间的180 d中，对NH⁺₄-N和NO^-₂-N去除率均达到99.9％以上，总氮去除率保持在90％以上，NO^-₃-N产生量在20～30 mg/L之间波动。研究表明,UASB厌氧氨氧化反应器处理废水效果明显，对NH⁺₄-N、NO^-₂-N和TN去除率高，NO^-₂-N和NH⁺₄-N比值可以指示厌氧氨氧化反应器性能的演变。UASB反应器稳定运行阶段容积负荷的影响较小，ANAMMOX菌对合成废水适应性强，反应器抗冲击能力较强，受冲击后恢复迅速。出水pH值稳定在8.5附近，pH值变化情况可作为反应器运行状况的指示。关键词硝化厌氧氨氧化上流式厌氧污泥床生物脱氮     

悬浮填料生物塔净化低浓度氮氧化物废气研究

采用多孔球型悬浮填料挂膜的生物塔净化低浓度氮氧化物废气的研究结果表明,氮氧化物的净化效率可达60%，适宜的入口NOx浓度为130 mg/m³，O₂体积含量为18%，空床停留时间为29 s，循环液流量为116.8 L/h, 循环液pH为7.49~8.05，压降为244.9 Pa，温度为22~28 ℃。NO^-₃和NO^-₂浓度相近的现象说明反硝化细菌存在，并发挥着反硝化作用，将部分NO^-₃转化为NO^-₂。     

花叶芦竹水平潜流人工湿地脱氮性能研究

采用花叶芦竹水平潜流人工湿地处理生活污水，对其脱氮性能进行研究。结果表明：在HRT＝5 d，对TOC，NH⁺₄-N，NO^-₂-N，NO^-₃-N和TN的去除效果分别达到92％、93％、84％、51％和88％，相应空白湿地的去除率分别为91％、85％、-232％、-203％和66％。大部分TOC在湿地的前端被去除。花叶芦竹可以直接吸收氮素，向湿地输送氧气，通过根系分泌物提供碳源。因此，花叶芦竹人工湿地具有很好的硝化反硝化能力，实现了良好的脱氮性能。     

复合沸石滤床修复北方景观水体的实验研究

以天然矿物质沸石、细砂及煤渣取代传统滤料构建复合基质生态床，表面种植景观植物，采用下向流-上向流运行方式修复北方景观水体。分别进行静态实验及不同循环速率下的动态实验，考察对水体污染物去除过程。结果表明，2种运行方式下对水体NH⁺₄-N去除率都在85%以上，其中以1 h为循环周期的运行方式去除率达97%，较静态提高12.8%；TN去除率最高为84%；TP去除不稳定，过程缓慢。煤渣层对NH⁺₄-N的去除效果差，硝化作用不彻底与反硝化作用的加强使下层出水NH⁺₄-N 、NO^-₂-N及NO^-₃-N浓度均高于上层。提高循环速率有利于对氮的去除。     

污水生物生态处理工艺中的脱氮机理研究

通过水解池-美人蕉湿地、水解/接触氧化池-菖蒲湿地现场实验装置考察了生物-生态工艺深度净化分散生活污水的效果。结果表明,水解池-美人蕉湿地尽管湿地停留时间达到7 d，出水NH⁺₄-N仍难以达到一级A（GB18918-2002）标准；而增加接触氧化池后，湿地停留时间仅2 d，组合工艺出水水质远优于一级A出水要求。美人蕉湿地脱氮的主要途径是湿地微生物的硝化/反硝化，植物吸收约占28%。对经接触氧化处理，NH⁺₄-N、NO^-₃-N浓度均较高的进水，菖蒲湿地可在C/N小于2时高效脱氮。菖蒲湿地对TN的去除占组合工艺TN去除量的79%，其中植物吸收仅占湿地除氮总量的8%。湿地介质的厌氧氨氧化活性试验表明，菖蒲湿地介质表面的微生物在无有机碳源存在的条件下，可使培养液中的NH⁺₄-N与NO^-₃-N、NO^-₂-N短期内发生同步脱氮，厌氧氨氧化可能是菖蒲湿地在进水低碳源条件下脱氮的主要原因。     

水平潜流人工湿地系统处理微污染原水的研究

采用水平潜流人工湿地系统处理微污染原水，同时考察了水力停留时间、温度、水力负荷以及植物的生长状况等对人工湿地系统处理效果的影响。结果表明，水平潜流人工湿地系统对微污染原水有较好的处理效果，COD、TP、TN、NH⁺₄-N、NO^-₃-N和NO^-₂-N的平均去除率分别为51.55%、49.90%、51.74%、 47.36%、52.67%和63.23%。按照国家地表水环境质量标准（GB3838-2002），经过湿地处理后，出水COD平均值达到Ⅰ类；出水TP平均值达到Ⅱ类；出水TN平均值基本接近Ⅳ类；出水NH⁺₄-N平均值达到Ⅱ类。另外，研究表明, 本系统在水力停留时间为3 d时,水力负荷为0.2 m/d处理效果最好，温度的变化与污染物的去除率呈正相关关系，植物生长旺盛程度直接影响着整个系统的处理效果。     

一体化A/O移动床生物膜反应器中DO、TN分布及脱氮效果研究

采用一体化A/O移动床生物膜法工艺，以模拟生活污水研究了该工艺的除碳脱氮效果，并对一体化移动床生物膜反应器的好氧区和缺氧区各纵向断面的COD、DO、NH₃-N、TN、NO^-₃-N和NO^-₂-N进行了检测，通过对缺氧区各断面的DO和TN浓度分布情况，分析了脱氮的产生过程。试验结果表明: 在水力停留时间HRT＝12 h，好氧区DO保持5 mg/L左右，COD进水浓度处于250～400 mg/L时，COD的去除率均在90%以上，且出水COD均在40 mg/L以下；TN进水浓度为20～50 mg/L时，NH₃-N去除率高于90%，其出水浓度可达到5 mg/L以下，脱氮效率也较高，TN去除率可达到65%～85%。COD和NH₃-N的浓度分布状况表明该一体化A/O移动床生物膜反应器的流态趋于全混式。     

几种阴阳离子对磷钨酸光催化降解甲基橙的影响

以磷钨酸为光催化剂，在紫外灯照射下，对甲基橙溶液进行光催化降解，考察了几种阴阳离子对磷钨酸光催化降解甲基橙溶液的影响。结果表明：Mg²⁺、Ca²⁺、NO^-₃、SO^2-₄和CO^2-₃均对催化活性有促进作用，其中Mg²⁺和Ca²⁺仅有微弱的促进作用；NO^-₃和SO^2-₄随着浓度的增加促进作用也有所增加；CO^2-₃则随着浓度的增加促进作用呈下降趋势；Mn²⁺、Al³⁺和Cl^-对光解反应存在较强的抑制作用，且Al³⁺和Cl^-随着其浓度的增加，抑制作用增强。     

水体中常见无机阴离子对TiO2薄膜光催化降解甲醛的影响

选择了5种水体中常见的阴离子(Cl^-，SO^2-₄，HPO^2-₄/HPO^2-₄，HCO^-₃/CO^2-₃和NO^-₃)，分别考查了其对TiO₂薄膜光催化降解模拟甲醛废水的反应速率的影响；从上述离子的光吸收，对·OH的捕获及其生成的相应的无机自由基的氧化作用以及与甲醛的竞争吸附3个方面讨论了上述离子影响TiO₂薄膜光催化降解模拟甲醛废水的反应速率的原因。结果表明，HCO^-₃/CO^2-₃对TiO₂薄膜光催化降解甲醛具有抑制作用，Cl^-和SO^2-₄的影响不大，H₂PO^-₄/HPO^2-₄和NO^-₃具有促进作用。造成上述结果的主要原因是HCO^-₃/CO^2-₃具有很强的·OH捕获作用；Cl^-，SO^2-₄对·OH捕获作用以及竞争吸附都较弱；H₂PO^-₄/HPO^2-₄在TiO₂表面具有较强的吸附能力，释放出的H⁺起到了酸催化剂的作用；NO^-₃在紫外光的照射下可以产生·OH，此外NO^-₃作为电子受体而降低了TiO₂表面光生电子和空穴的复合几率。     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

A History of Dry Cleaners and Sources of Solvent Releases from Dry Cleaning Equipment

Approximately 25, 000-35, 000 dry cleaning facilities currently operate in the U.S. The release of perchloroethylene and other solvents from these establishments represents a major source of soil and groundwater contamination. The manner in which dry cleaning solvents escape from dry cleaning plants is, for all practical purposes, identical for chlorinated and petroleum hydrocarbon solvents and is related to one of the following events: the catastrophic failure of a component of the dry cleaning system, the improper installation, operation or maintenance of the dry cleaning equipment or a combination of all of these causes. Acceptable customs, codes and regulations can also dictate what is authorized for operation of a dry cleaning facility in a particular community, geographic area during a particular time frame. Environmental litigation dealing with the origin of a solvent release from dry cleaners tends to focus on the design and manufacture of dry cleaning industry machines such as washers, washer extractors, tumblers, solvent filters, water separators, stills and spotting boards. A thorough analysis of the daily operations of dry cleaners often reveals that poor maintenance, failure to follow the manufacturer's instructions and the actions of the operator are the most likely causes of soil and groundwater pollution. In order to forensically evaluate the most probable origins of a solvent release and to examine issues regarding liability, a thorough understanding of the history of dry cleaning and a detailed analysis of the operation and maintenance of the dry cleaning equipment are necessary. The discovery of solvent plumes in the vicinity of dry cleaning plants may suggest that the solvent source is the dry cleaning plant; however, the presence of these plumes does not necessarily indicate that the dry cleaning equipment was defectively designed or manufactured. A thorough review of the type of equipment used over the life of the dry cleaning plant and verifiable solvent mileage records frequently indicates that operators of the plant have disposed of solvent and contaminated solids into the municipal sewer or on ground surfaces.     

Radionuclides in deer and elk from Los Alamos national laboratory and the doses to humans from the ingestion of muscle and bone

Abstract

This paper summarizes radionuclide concentrations (³H, ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu, ²⁴¹Am, and ^totU) in muscle and bone tissue of mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) collected from Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer (n = 11) and elk (n = 22) collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer (n = 3) and elk (n = 7) collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDEs (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (50 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.22 mrem y^‐1 (2.2 μSv y^‐1), deer bone = 3.8 mrem y^‐1 (38 μSv y^‐1), elk muscle = 0.12 mrem y^‐1 (1.2 μSv y^‐1), and elk bone = 1.7 mrem y^‐1 (17 μSv y^‐1). All CEDEs were far below the International Commission on Radiological Protection guideline of 100 mrem y^‐1 (1000 μSv y^‐1), and the highest muscle plus bone net CEDE corresponded to a RECF of 2E‐06, which is far below the Environmental Protection Agency upper level guideline of 1E‐04.     

Leaching of seven pesticides currently used in cotton crop in Mato Grosso State—Brazil

This study aimed to evaluate the leaching of pesticides and the applicability of the Attenuation Factor (AF) Model to predict their leaching. The leaching of carbofuran, carbendazim, diuron, metolachlor, α and β endosulfan and chlorpyrifos was studied in an Oxisol using a field experiment lysimeter located in Dom Aquino – Mato Grosso. The samples of percolated water were collected by rain event and analyzed. Chemical and physical soil attributes were determined before pesticide application to the plots. The results showed that carbofuran was the pesticide that presented a higher leaching rate in the studied soil, so was the one representing the highest contamination potential. From the total carbofuran applied in the soil surface, around 6 % leached below 50 cm. The other pesticides showed lower mobility in the studied soil. The calculated values to AF were 7.06E-12 (carbendazim), 5.08E-03 (carbofuran), 3.12E-17 (diuron), 6.66E-345 (α-endosulfan), 1.47E-162 (β-endosulfan), 1.50E-06 (metolachlor), 3.51E-155 (chlorpyrifos). AF Model was useful to classify the pesticides' potential for contamination; however, that model underestimated pesticide leaching.     

Endosulfan in China 2—emissions and residues

Background, aim, and scope  Endosulfan is one of the organochlorine pesticides (OCPs) and also a candidate to be included in a group of new persistent organic pollutants (UNEP 2007). The first national endosulfan usage inventories in China with 1/4° longitude by 1/6° latitude resolution has been reported in an accompanying paper. In the second part of the paper, we compiled the gridded historical emissions and soil residues of endosulfan in China from the usage inventories. Based on the residue/emission data, gridded concentrations of endosulfan in Chinese soil and air have been calculated. These inventories will provide valuable data for the further study of endosulfan. Methods  Emission and residue of endosulfan were calculated from endosulfan usage by using a simplified gridded pesticide emission and residue model—SGPERM, which is an integrated modeling system combining mathematical model, database management system, and geographic information system. By using the emission and residue inventories, annual air and soil concentrations of endosulfan in each cell were determined. Results and discussion  Historical gridded emission and residue inventories of α- and β-endosulfan in agricultural soil in China with 1/4° longitude by 1/6° latitude resolution have been created. Total emissions were around 10,800 t, with α-endosulfan at 7,400 t and β-endosulfan at 3,400 t from 1994 to 2004. The highest residues were 140 t for α-endosulfan and 390 t for β-endosulfan, and the lowest residues were 0.7 t for α-endosulfan and 170 t for β-endosulfan in 2004 in Chinese agricultural soil where endosulfan was applied. Based on the emission and residue inventories, concentrations of α- and β-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell. We have estimated annual averaged air concentrations and the annual minimum and maximum soil concentrations across China. The real concentrations will be different from season to season. Although our model does not consider the transport of the insecticide in the atmosphere, which could be very important in some areas during some special time, the estimated concentrations of endosulfan in Chinese air and soil derived from the endosulfan emission and residue inventories are in general consistent with the published monitoring data. Conclusions  To our knowledge, this work is the first inventory of this kind for endosulfan published on a national scale. Concentrations of the chemical in Chinese air and agricultural surface soil were calculated for each grid cell. Results show that the estimated concentrations of endosulfan in Chinese air and soil agree reasonably well with the monitoring data in general. Recommendations and perspectives  The gridded endosulfan emission/residue inventories and also the air and soil concentration inventories created in this study will be updated upon availability of new information, including usage and monitoring data. The establishment of these inventories for the OCP is important for both scientific communities and policy makers.     

Impact of spiked concentrations of Cd,Pb, As and Zn in growth medium on elemental uptake of Nasturtium officinale (Watercress)

This study is aimed at investigating the impact of water quality on the uptake and distribution of three non-essential and toxic elements, namely, As, Cd and Pb in the watercress plant to assess for metal toxicity. The plant was hydroponically cultivated under greenhouse conditions, with the growth medium being spiked with varying concentrations of As, Cd and Pb. Plants that were harvested weekly for elemental analysis showed physiological and morphological symptoms of toxicity on exposure to high concentrations of Cd and Pb. Plants exposed to high concentrations of As did not survive and the threshold for As uptake in watercress was established at 5 ppm. Translocation factors were low in all cases as the toxic elements accumulated more in the roots of the plant than the edible leaves. The impact of Zn on the uptake of toxic elements was also evaluated and Zn was found to have an antagonistic effect on uptake of both Cd and Pb with no notable effect on uptake of As. The findings indicate that phytotoxicity or death of the watercress plant would prevent it from being a route of human exposure to high concentrations of As, Cd and Pb in the environment.     

Butyltin compounds in sediment and fish from the Polish Coast of the Baltic Sea

Concentrations of mono- (MBT), di- (DBT), and tri-(TBT) butyltin compounds were measured in eggs, liver, and muscle of nine species of fish from four regions of the Baltic Sea - the Firth of Vistula, the Gulf of Gdańsk, Puck Bay, and the mouth of the Vistula River. The overall concentration ranges among all the fish sampled from the four sites were: < 7 to 79 ng/g for MBT, 6 to 1100 ng/g for DBT, 7 to 3600 ng/g for TBT, and 16 to 4800 ng/g for total BTs, on a wet wt basis. The highest concentration of total BTs was found in herring liver from the Firth of Vistula (4800 ng/g, wet wt) and in roach muscle from Puck Bay (3300 ng/g, wet wt), while the least concentration was found in burbot eggs and liver from the Vistula River (39 and 32 ng/g, wet wt, respectively). TBT was the major form of BTs present in most samples analyzed. Sediment samples collected from shipyards in the Gulf of Gdańsk contained butyltin concentrations ranging from 1.2 to 46 μg/g (dry wt) for MBT, 2.0 to 42 μg/g for DBT, and 2.6 to 40 μg/g for TBT. As with the fish, the majority of the BTs in sediment were present as TBT, which suggested recent exposure of the aquatic environment of the region to TBT.     

Malathion-induced sublethal toxicity on the hematology of cricket frog (Fejervarya limnocharis)

The effect of malathion [diethyl(dimethoxythiophosphorylthio)succinate] at sublethal concentration (0.006 ppm) on hematological parameters of the cricket frog (Fejervarya limnocharis) was studied for 24 hrs to 240 hrs of exposure and remarkable hematological alterations were observed. The study on hematological parameters revealed a highly significant decrease (P < 0.01) in the total erythrocytes count in malathion-exposed animals from 24 hours to 96 hrs of exposure as compared to control. Significant decreases (P < 0.01) of hemoglobin and packed cell volume were also observed from 48 hrs to 240 hrs. A significant increase (P < 0.01) in leucocytes count was noted throughout the exposure period. Elevated numbers of lymphocytes and eosinophils as found in the present study revealed lymphocytosis as well as eosinophilia, suggesting that this was a result of direct stimulation of the immunological defense due to the presence of a toxic substance or may be associated with tissue damage. The cytomorphological and cytopathological study of erythrocytes and leucocytes in malathion-exposed frogs at 0.006 ppm concentration revealed various cytotoxic effects at different exposure times. It was noted that the size and the shape of the erythrocytes were subjected to variation in different blood disorders.