城市生活垃圾焚烧处理过程中重金属迁移规律研究

通过采集厦门2个垃圾焚烧发电厂进厂垃圾、渗滤液、飞灰、炉渣和烟气样品，分析垃圾组成成分及各组分的重金属含量，结果表明，垃圾中以厨余、橡塑类和纸类为主，共占到垃圾干基的78．08％，重金属含量大小次序为Zn〉Cu〉Pb〉Cr〉Ni〉Cd〉Hg；垃圾渗滤液中除Zn外，其他金属的含量都较低，一厂渗滤液中重金属Ni、Zn迁移量较大，分别达到24．46％和8．52％。二厂渗滤液中重金属的迁移有相同的趋势，但含量相对较高。垃圾焚烧后其重金属主要分布在飞灰和废渣中，烟气中的含量非常少，不同金属的含量均有差别，这与金属的性质有很大关系；通过浸出毒性分析，飞灰中重金属酸溶态含量多，容易浸出，属于危险废物。同时，不同烟气处理工艺产生的飞灰的重金属浸出量有很大差别。     

城市生活垃圾焚烧飞灰的熔融分离处理

焚烧法处理城市生活垃圾已在世界先进发达国家广泛采用。垃圾焚烧飞灰含有大量的重金属，必须进行合理安全处置。在分析城市生活垃圾焚烧飞灰的物理化学性质基础上，研究了垃圾焚烧飞灰固化成型、熔融分离的无害化处理新工艺。实验结果表明：飞灰固化成球的适宜粘结剂为5%～7%消石灰，养护时间为10～12 d，固化球强度达0.24 kg/cm²以上，可以满足运输和熔化分离要求；固化后的飞灰在1 300℃左右熔融分离后，重金属的分离效果好，达到97%以上，可达到无害化处理标准；对1 300℃和1 400℃熔融分离后熔渣的重金属浸出毒性测试显示，重金属浸出毒性问题可以完全解除。研究结果表明，采用飞灰固化-熔融分离工艺处理城市生活垃圾焚烧飞灰是可行的。     

重庆市垃圾焚烧飞灰特性及重金属浸出行为的研究

通过激光粒度仪分析了重庆市垃圾焚烧飞灰颗粒粒径的分布特征,并研究了在GB5085.3-2007和USEPA-TCLP浸出条件下及不同pH、浸出液固比和浸出时间等因素下重庆市垃圾焚烧飞灰中重金属的浸出行为.结果表明,重庆市垃圾焚烧飞灰颗粒平均粒径为36.4μm,飞灰中主要重金属总量约1.04%,Zn、Pb含量较高,具有较...     

矿渣高温固化垃圾焚烧飞灰中的重金属

垃圾焚烧飞灰由于含有大量重金属属于危险固体废物,重金属的浸出含量影响其资源化利用。模拟高炉矿渣在熔融状态下固熔部分飞灰,研究固熔体急冷后其重金属的浸出规律,采用SEM-EDS、XRD、FTIR研究固熔体固化重金属的机理。结果表明:重金属浸出量随着熔融温度的升高而减少,随着飞灰掺量的增加而增加,但浸出浓度远低于国家标准;SEM-EDS表明,主要重金属均出现在固熔体中;XRD证实有部分Zn以生成Ca_2ZnSi_2O_7的形式被固化;FTIR的结果也表明固化的重金属影响了Si—O—Si键的周围环境。     

油页岩循环流化床锅炉底渣和飞灰中重金属元素浸出毒性研究

为了研究我国桦甸油页岩65 t/h循环流化床锅炉的底渣和飞灰中重金属元素Cr、Cu、Pb和Zn的赋存状态及不同酸度条件下的浸出特性,分别进行了逐级提取实验和分批浸出的淋滤实验。逐级提取实验结果表明,这4种元素在底渣和飞灰中具有基本相当的赋存状态。硫化物结合态和稳定的残渣态是各元素的主要赋存状态,元素的潜在浸出能力大小表现为:PbCrCuZn,飞灰中各元素的潜在浸出能力大于底渣中的。浸出实验结果表明,元素的赋存状态决定了其浸提能力,浸提液的pH值对各元素浸出能力的影响不尽相同,各元素的浸出能力随浸提时间的延长都会趋于平衡,Cr和Pb的浸出浓度都高于地表水和饮用水的国家标准。     

再生铝飞灰重金属的浸出毒性特征及其控制

采用再生铝飞灰为研究样品,研究了飞灰重金属浸出毒性水平以及飞灰浸出毒性特征,同时探讨了飞灰的处理处置工艺。结果表明:飞灰中Pb、Cd和Zn浸出浓度超标,超标率为100%,属于具有浸出毒性的危险废物,必须对其进行稳定和固化;再生铝飞灰中锌的浸出浓度所占比例最大,铅的浸出浓度次之,两者之和占总量的98%以上,再生铝飞灰中主要有害重金属为Zn和Pb;并结合当前飞灰的处理处置工艺,提出的可能的控制方法为水泥固化和药剂稳定法,为同类研究提供参考。     

医疗垃圾焚烧飞灰重金属形态分析

利用原子吸收光谱仪分别对医疗垃圾焚烧飞灰重金属含量和重金属形态及其随颗粒度分布特性进行了分析,结果表明,飞灰中Cd、Zn、Pb等的浸出浓度远超标与这些重金属的可交换态和碳酸盐态含量较高有关;飞灰颗粒度主要在96 μm以下,96～150 μm的颗粒中Cd、Pb含量最高,且Zn、Cd的形态以可交换态为主.     

垃圾焚烧飞灰中不同粒径的毒性特性

对广州市某垃圾焚烧发电厂的焚烧飞灰进行粒径分级毒性分析研究。主要研究了粒径在35～1 000μm范围内的飞灰的腐蚀性和短期浸出毒性,包括Cr、Cd、Mg、Pb、Mn、Fe、Cu、Zn、Ni、Co等重金属,SO24-,Cl-,NO3--N和NO2--N,同时也研究了飞灰的物质组成和矿物特性。研究结果表明,所有粒径飞灰的浸出液pH值在12.3～12.5之间,属于有腐蚀性的危险废物,重金属Mg、Pb、Zn的浸出浓度最高,分别为168.78、53.94和86.40 mg/L。飞灰浸出液和含量最高分别达到8.87g/L和1.38 g/L,同时浸出液中测出一定量的硝态氮和亚硝态氮,证明飞灰吸附了垃圾焚烧过程中产生的氮氧化物气体。另外,研究得出飞灰的基本组成元素为Ca、Si、Cl、K、Na、S、Al、Mg和Fe,而重金属则以Zn、Pb、Mn、Cu、Cr等为主。矿物相主要为含硅和钙的化合物及NaCl和KCl等氯化物。     

垃圾焚烧飞灰中重金属固化稳定机理及系统评价方法的研究进展

垃圾焚烧飞灰中的重金属是必须处理的环境污染物.目前,对于垃圾焚烧飞灰的固化稳定化处理已经有了大量的实验研究.但是,不同地区垃圾焚烧厂产生的飞灰中,重金属含量和形态大不相同,故相应的飞灰仍然难以实现大规模、普适性的处理.在查阅文献及实际调研的基础上,系统总结了垃圾焚烧飞灰中重金属的存在形态与浸出特性;通过对重金属固化稳定机理的分析,指出了垃圾焚烧飞灰固化材料和稳定剂选择的方向.此外,还计算了不同的固化剂与稳定剂对不同重金属的固化率,发现材料复配的方式对多种重金属的稳定效果较好.最后,比较了不同评价方法在垃圾焚烧飞灰固化系统选择中的应用效果,指出综合评价方法是目前相对较完善、系统的方法,在工程实际中具有广阔的应用前景.     

垃圾焚烧飞灰对染料（亚甲基蓝）的吸附性能

以垃圾焚烧飞灰为吸附剂对亚甲基蓝进行了吸附脱色实验。主要探讨了飞灰粒径、用量、温度、pH值和初始浓度等因素对亚甲基蓝吸附的影响，同时分析了吸附上清液中重金属Pb和Cr的浸出毒性。研究结果表明，在25—45℃、pH值2～12、飞灰用量1～5g范围内，经过180min吸附，亚甲基蓝的脱色率都达75％以上，最高可达99．46％。实验还得出，除重金属Pb外，吸附上清液中重金属的浸出量远远低于《危险废物鉴别标准浸出毒性鉴别》的限定值。因此，若能降低重金属Pb的浸出，飞灰将具有应用于处理染料废水的巨大潜力。     

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.