仿生矿化法制备壳聚糖/纳米CdS复合粒子对猩红B光催化降解研究

用仿生矿化法制备了壳聚糖/纳米CdS复合粒子，并用于可见光光催化降解猩红B染料模拟废水，系统地研究了染料初始浓度、pH值、催化剂投加量、光照情况和催化剂重复使用等因素对猩红B的光解脱色效率的影响。结果表明，当pH=3.0，催化剂投加量为0.7 g/L的条件下，对初始溶液为20 mg/L的猩红B模拟废水，60 min之内脱色率超过96%。酸性媒介比碱性媒介更有利于猩红B染料光解脱色。实验范围内Br^-、NO^-₃和Cl^-等无机阴离子，均对降解脱色有促进作用，其中NO₃^-对脱色作用促进最显著。处理前后的UV-Vis谱图分析表明猩红B在壳聚糖/纳米CdS复合粒子可见光光解处理过程中脱色是因为染料发生氧化光降作用。催化剂重复利用5次后，处理60 min对猩红B的脱色率仍可达到80.7%。     

Trametes sp. LS-10C漆酶对直接类偶氮染料的脱色作用

利用栓菌(Trametes sp.LS-10C)漆酶在单酶和漆酶-介体体系2种情况下对3种直接类偶氮染料进行脱色。结果表明,在给酶量为10 U·m L~(-1)、染料浓度为100 mg·m L~(-1)条件下反应24 h后,直接蓝86在非介体体系中脱色率达到71.2%,其最适脱色温度和pH范围分别为45~60℃和3.5~5.0;直接橙26在介体体系(10μmol·L~(-1)ABTS)中脱色率达到78.7%,其最适脱色温度和pH范围分别为35~45℃和4.5~6.5;直接红31在介体体系(10μmol·L~(-1)ABTS)中脱色率达到90.7%,其最适脱色温度和pH范围分别为35~45℃和3.5~5.0。     

Fe/活性炭多相类Fenton法湿式氧化罗丹明B废水的研究

采用自制的Fe/活性炭（Fe/AC）为催化剂，H₂O₂为氧化剂,组成多相类Fenton试剂催化降解罗丹明B染料废水。实验结果表明,在催化剂加入量为0.8 g/L，H₂O₂体积分数为0.3%,废水pH值为13,反应时间为30 min的条件下,质量浓度为200 mg/L的罗丹明B染料废水的脱色率达100%。反应动力学研究表明,罗丹明B脱色反应近似为一级反应,30℃时反应速率常数为0.02675 min^-1,表观活化能为69.47 kJ/mol。     

直接红染料的臭氧脱色与中间产物研究

以直接红B模拟染料废水为研究对象，考察了臭氧化过程中染料溶液的吸光度和TOC的变化，同时利用离子色谱仪和GC/MS对染料的降解过程进行了分析，最后用发光细菌法检测了染料溶液急性毒性的变化。结果表明，臭氧对染料的降解符合一级反应动力学，20 min时对染料的脱色率达到99.2%；反应40 min后TOC减少32.55%，染料分子有97.8%的S被氧化为SO^2-₄，偶氮键被臭氧化为N₂，分子中的仲胺基小部分转化成游离NH⁺₄和NO^-₃；在臭氧化过程前期新生成的醛类和酰胺类物质使溶液急性毒性迅速上升，25 min后溶液毒性开始逐渐下降。     

Ganoderma sp.SYBC L48漆酶酶学性质及其对酸性红1的脱色性能

对灵芝菌Ganoderma sp. SYBC L48漆酶进行了纯化和酶学性质分析,并利用该漆酶对偶氮染料酸性红1进行脱色处理;考察了脱色体系中各因素对脱色效率的影响;采用小麦种子和水稻种子对酶处理后的染料进行了毒性测试。结果表明,以ABTS为底物时,该酶的最适pH为2.5,最适温度为60℃,在pH5～9和20～60℃具有良好的稳定性,Co2+、Cr~(3+)和Fe~(3+)离子对酶活性有较强的抑制作用。在染料浓度100 mg·L-1,酶浓度0.5 U·mL-1,介体HOBT浓度0.25 mmol·L-1,pH为4,50℃的条件下反应30 min后,该漆酶对酸性红1的脱色率可达90.3%;1 mmol·L-1的Cr~(3+)、Cu~(2+)、Al~(3+)和Ni~(2+)存在下,漆酶仍能催化酸性红1脱色;脱色后染料的植物毒性下降。上述结果表明该漆酶在纺织废水处理中具有一定的应用前景。     

微波诱导鳞片石墨-H2O2催化氧化处理甲基紫废水

研究微波诱导鳞片石墨-H₂O ₂催化氧化处理甲基紫废水工艺,探讨各种因素的协同作用及对废水脱色效果的影响,并采用SEM、EDX、XRD和FTIR对新鲜及使用6次后的鳞片石墨进行表征。结果表明,微波诱导鳞片石墨-H₂O₂能高效快速降解废水中的甲基紫;在50 mL初始pH为3,质量浓度为10 mg/L的甲基紫废水中, H₂O₂用量1 mL/L,鳞片石墨 3 g/L,微波输出功率259 W,微波辐射时间9 min的最佳处理工艺条件下,甲基紫脱色率达到了98.80%;微波、鳞片石墨、H₂O₂体系对甲基紫废水降解效果明显,产生协同效应。紫外-可见光谱分析表明,废水中甲基紫结构被破坏,但仍含有少量苯环等小分子。动力学研究表明,脱色反应符合一级反应动力学规律,反应速率常数k为0.42613 min^-1,反应半衰期t_1/2为1.626 min。     

底泥修复对城市污染河道水体污染修复的影响研究

为开发城市黑臭河道的有效治理方法，利用人工模拟河道就河道底泥对上覆水体的二次污染、底泥污染生物修复对其氮磷营养盐释放及河道水体污染生物修复的影响进行了研究，并对实验结果进行了工程现场应证。研究结果表明：河道污染底泥生物修复状况对上覆水体水质产生大的影响，在底泥不加修复时，底泥污染物释放使水体COD、TP、NH₃-N浓度分别达到30～35 mg/L、0.4～0.5 mg/L和3.0 mg/L，底泥修复后分别为15～20 mg/L、0.1 mg/L和2.5 mg/L；底泥G值（y）与底泥氮、磷污染物释放量（x）呈负相关关系，关系式分别为：y=0.5124x-0.1394（R₂=0.9222），y=0.17772x-0.4781（R₂=0.8701）；结合底泥的生物修复，采用曝气增氧投加生物制剂措施对水体进行生物修复时COD、NH₃-N和PO^3-₄的去除率分别提高13.6%、25.0%和15.7%；对古廖涌的现场治理工程表明，在未对河道底泥进行生物修复的情况下，经过氧化塘预处理河道水体增氧-水体原位强化生物修复等措施的治理，河道中、下游水体又逐渐恢复黑臭，在对河道底泥进行修复后，河道污染水体水质得到显著的改善和提高。     

碳酸根对磷酸钙沉淀反应回收磷的影响简

以模拟的厌氧消化液为处理对象，通过小试实验，考察不同初始磷浓度C_P、Ca/P物质的量比、pH和温度下，碳酸根（CO₃^2-）对磷酸钙沉淀反应回收磷的影响；利用扫描电镜（SEM）、X射线衍射仪（XRD）和傅里叶变换红外光谱（FTIR）对沉淀产物进行表征。结果表明，高浓度的CO₃^2-对以磷酸钙沉淀反应去除和回收磷的效率影响较大；C_P相同时，CO₃^2-浓度（C_CO3^2-）越大，P的去除率越低，低C_P（20 mg/L）时尤为显著；当C_CO3^2-相同时，随着C_P的增大，反应速率加快，P的去除率逐渐升高，但升高幅度越来越小；增大Ca/P比和pH能提高P的去除率，降低CO₃^2-对磷酸钙沉淀反应的抑制作用，综合考虑实际效果，应选择Ca/P比为3.33，pH为9.0作为适宜的反应条件；升高温度对降低CO₃^2-对磷酸钙沉淀反应的抑制作用贡献不大。在C_P为60 mg/L，Ca/P比为1.67，pH为9.0，温度为20℃的条件下，当C _CO3^2-为0时，得到的沉淀产物主要为羟基磷灰石HAP；当C _CO3^2-为30 mmol/L时，得到的沉淀产物为磷酸钙和碳酸合磷灰石的混合物。     

灵芝漆酶对直接蓝86的催化脱色性能

利用灵芝菌Ganoderma lucidum U-281漆酶对直接蓝86进行酶促氧化脱色,并对其降解机理进行了探讨。结果表明,染料-漆酶共反应体系在20～50℃及pH小于5.0范围内,直接蓝86均可脱色50%以上;漆酶对直接蓝86具有宽泛的浓度适应性,对300 mg/L的该染料仍具有耐受性。最优脱色工艺参数为温度40℃、pH 5.0、染料初始浓度200 mg/L、漆酶用量1 U/mL。在优化条件下,直接蓝863 h的脱色率达到54.54%,48 h脱色率达到91.54%。紫外-可见吸收光谱分析表明,漆酶的酶促氧化导致染料的分子结构产生了变化,是造成直接蓝86脱色的主要发生机制。     

Keggin型Fe-Mo-Zr杂多酸盐光催化剂的制备及性能研究

利用水热合成法制备了Keggin结构的Fe-Mo-Zr杂多酸盐光催化剂，并利用红外光谱（IR）对催化剂进行了表征。实验以酸性大红（GR）为模拟污染物，考察了在紫外灯照射下，Fe-Mo-Zr杂多酸盐的投加量、污染物的浓度和pH值以及外加H₂O₂对光催化降解效果的影响。实验结果表明，当催化剂的投加量为0.6 g/L，pH为5～7，初始浓度为10 mg/L的GR染料溶液，光照160 min，脱色率可达87.98%。外加H₂O₂可以提高光催化反应效率。     

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.     

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 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.     

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

The effect of malathion [diethyl(dimethoxythiophosphorylthio)succinate] at sublethal concentration (0.006 ppm) on intestinal parameters of cricket frog (Fejervarya limnocharis) was studied for 24 hrs to 240 hrs of exposure and remarkable histopathological alterations were observed. The study on intestinal parameters revealed acute pathological conditions in the intestinal wall. The toxic effect became evident as the cytoplasm of the cells disintegrated and the cells became empty and vacuolated. The cell membranes were also ruptured. Degenerative changes of the absorptive surface (villi) of the intestine in the different periods of exposure were pronounced. Severe atrophic nature (necrotic mucosa) of the intestine began from 48 hrs onwards to 96 hrs of exposure.     

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.     

Nitrogen leaching and acidification during 19 years of NH₄NO₃ additions to a coniferous-forested catchment at Gårdsjön, Sweden (NITREX)

The role of nitrogen (N) in acidification of soil and water has become relatively more important as the deposition of sulphur has decreased. Starting in 1991, we have conducted a whole-catchment experiment with N addition at Gårdsjön, Sweden, to investigate the risk of N saturation. We have added 41 kg N ha⁻¹ yr⁻¹ as NH₄NO₃ to the ambient 9 kg N ha⁻¹ yr⁻¹ in fortnightly doses by means of sprinkling system. The fraction of input N lost to runoff has increased from 0% to 10%. Increased concentrations of NO₃ in runoff partially offset the decreasing concentrations of SO₄ and slowed ecosystem recovery from acid deposition. From 1990-2002, about 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. The soil N pool increased by 5%. N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g⁻¹.     

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.