活性污泥法处理焦化污水监测值的统计特性

用活性污泥法处理焦化污水,将一年内监测的曝气池山水和入水中酚、氰、氨氮、COD等指标建立数据库,并进行时间序列、正态分布性、自相关和线性回归分析.统计分析结果表明,多数指标呈正态分布而周期性特征不明显;经多元线性回归分析,出水COD与入水COD、出水酚之间的关系较为密切.     

热污染对陡河水库鱼类及其水环境的影响

研究表明,热污染对水环境影响主要表现在水温的频繁变化、水平和纵向上温差明显以及改变水生物的群落结构.寄生虫感染率增加,冷热冲击对胚胎发育的危害和浮游生物群落变化形成的饵料基础是影响鱼类数量和生长的重要因素,鱼类在群落中的生态位特点则决定着对各种变化的反应结果.     

浙江拔茅银矿地质特征及成因

拔茅银矿是浙东中生代火山岩带中近几年新发出的金银矿田,矿床发育于破火山口机构内,矿体主要受NW及近SN向张性硅化破碎带控制。矿床的各种特征表明,其成因属浅成低温热液型。     

Screening and degrading characteristics and community structure of a high molecular weight polycyclic aromatic hydrocarbon-degrading bacterial consortium from contaminated soil

Inoculation with effcient microbes had been proved to be the most important way for the bioremediation of polluted environments. For the treatment of abandoned site of Beijing Coking Chemical Plant contaminated with high level of high-molecular-weight polycyclic aromatic hydrocarbons(HMW-PAHs) ,a bacterial consortium capable of degrading HMW-PAHs,designated 1-18-1,was enriched and screened from HMW-PAHs contaminated soil.Its degrading ability was analyzed by high performance liquid chromatography(HPLC) ,and the community structure was investigated by construction and analyses of the 16S rRNA gene clone libraries(A,B and F) at different transfers.The results indicated that 1-18-1 was able to utilize pyrene,fluoranthene and benzoapyrene as sole carbon and energy source for growth.The degradation rate of pyrene and fluoranthene reached 82.8%and 96.2%after incubation for 8 days at 30°C,respectively;while the degradation rate of benzoapyrene was only 65.1%after incubation for 28 days at 30°C. Totally,108,100 and 100 valid clones were randomly selected and sequenced from the libraries A,B,and F.Phylogenetic analyses showed that all the clones could be divided into 5 groups,Bacteroidetes,α-Proteobacteria,Actinobacteria,β-Proteobacteria andγ-Proteobacteria.Sequence similarity analyses showed total 39 operational taxonomic units(OTUs) in the libraries.The predominant bacterial groups wereα-Proteobacteria(19 OTUs,48.7%) ,γ-Proteobacteria(9 OTUs,23.1%) andβ-Proteobacteria(8 OTUs,20.5%) . During the transfer process,the proportions ofα-Proteobacteria andβ-Proteobacteria increased greatly(from 47%to 93%) ,while γ-Proteobacteria decreased from 32%(library A) to 6%(library F) ;and Bacteroidetes group disappeared in libraries B and F.     

Oxidative removal of acetaminophen using zero valent aluminum-acid system: Efficacy, influencing factors, and reaction mechanism

Commercial available zero valent aluminum under air-equilibrated acidic conditions (ZVAl/H⁺/air system) demonstrated an excellent capacity to remove aqueous organic compounds. Acetaminophen (ACTM), the active ingredient of the over-the-counter drug Tylenol^®, is widely present in the aquatic environment and therefore the treatment of ACTM-contaminated water calls for further research. Herein we investigated the oxidative removal of ACTM by ZVAl/H⁺/air system and the reaction mechanism. In acidic solutions (pH < 3.5), ZVAl displayed an excellent capacity to remove ACTM. More than 99% of ACTM was eliminated within 16 hr in pH 1.5 reaction solutions initially containing 2.0 g/L aluminum and 2.0 mg/L ACTM at 25 ± 1\textcelsius. Higher temperature and lower pH facilitated ACTM removal. The addition of different iron species Fe⁰, Fe²⁺ and Fe³⁺ into ZVAl/H⁺/air system dramatically accelerated the reaction likely due to the enhancing transformation of H₂O₂ to HO. via Fenton's reaction. Furthermore, the primary intermediate hydroquinone and the anions formate, acetate and nitrate, were identified and a possible reaction scheme was proposed. This work suggested that ZVAl/H⁺/air system may be potentially employed to treat ACTM-contaminated water.     

Variations in the Emissions of Volatile Organic Compounds from the Toner for a Specific Photocopier

ABSTRACT

A laboratory thermal desorption apparatus was used to measure emissions from a number of nominally identical photocopier toners—manufactured to meet the specifications of one specific model copier—when these toners were heated to fuser temperature (180-200 °C). The objective was to assess how potential volatile organic compound (VOC) emissions from the toner for a given copier can vary, depending upon the production run and the supplier. Tests were performed on a series of toner (and associated raw polymer feedstock) samples obtained directly from a toner manufacturer, representing two production runs using a nonvented extrusion process, and on toner cartridges purchased from two local retailers, representing three different production lots (histories unknown). The results showed that the retailer toners consistently had up to 350% higher emissions of some major compounds (expressed as |ig of compound emit-ted/g of toner), and up to 100% lower emissions of others, relative to the manufacturer toners (p ≤ 0.01). The manufacturer toners from one production run had emissions of certain compounds, and of total VOCs, that were modestly higher (13-18%) than those from the other run (p ≤ 0.01). The emission differences between the retailer and manufacturer toners are probably due to differences     

A Cost-Effective Weighing Chamber for Particulate Matter Filters

ABSTRACT

Particulate matter (PM) is a ubiquitous air pollutant that has been receiving increasing attention in recent years due in part to the association between PM and a number of adverse health outcomes, including mortality and increases in emergency room visits and respiratory symptoms, as well as exacerbation of asthma and decrements in lung function.^1-5 As a result, the ability to accurately sample ambient PM has become important, both to researchers and to regulatory agencies. The federal reference method for the determination of fine PM as PM_2.5 in the atmosphere recommends that particle-sampling filters be conditioned and weighed in an environment with constant temperature and relative humidity (RH).⁶ It is also recommended that vibration, electrostatic charges, and contamination of the filters from laboratory air be minimized to reduce variability in filter weight measurements. These controls have typically been maintained in small, environmentally controlled “cleanrooms.” As an alternative to constructing an elaborate cleanroom, we have designed, and presented in this paper, an inexpensive weighing chamber to maintain the necessary level of humidity control.     

Acute and chronic toxicity of organophosphate monocrotophos to Daphnia magna

The acute and chronic toxicity of monocrotophos (MCP), the binary joint toxicity of MCP and bifenthrin (BF), and sodium dodecyl benzene sulfonate (SDBS) to Daphnia magna (D. magna) was evaluated. The 24 h-median effective concentration (24 h-EC₅₀) and 48 h-median lethal concentration (48 h-LC₅₀) of MCP towards D. magna were 161 and 388 μ g/L, respectively. In addition, the lowest-observed effective concentration (LOEC) and non-observed effective concentration (NOEC) of MCP to D. magna were 10 and 5 μ g/L, respectively. Furthermore, the chronic value (ChV) of MCP against D. magna was 7 μ g/L and the acute chronic ratio (ACR) was 55. The number of offspring per female and the intrinsic rate of natural increase (r) were identified as the parameters that were most sensitive to MCP. In addition, toxic unit (TU) analysis was employed to evaluate the joint toxicities. The calculated TU_mix values of binary equitoxic mixtures of MCP + BF and MCP + SDBS were 1.47 and 1.63, respectively, which suggests that both equitoxic mixtures exert a limited antagonistic effect. The results of this study revealed that the toxic threshold of MCP towards D. magna is higher than its reported highest residue (4 μ g/L) in the ordinary aquatic environment, and that concurrent exposure to BF or SDBS may exert a slight antagonistic effect.     

Monoclonal antibody produced by heterologous indirect enzyme-linked immunosorbent assay and its application for parathion residue determination in agricultural and environmental samples

A heterologous indirect enzyme-linked immunosorbent assay (ELISA) was developed, which was based on monoclonal antibody (Mab) to determine parathion residue in agricultural and environmental samples. Eight Mabs were produced by introducing the heterologous indirect ELISA into the screening procedure. It was shown that these Mabs had more broad-reactivity with twenty competitors than that of 5H7 (Mab produced by homologous screening). So it became much easier using these new Mabs to develop heterologous immunoassays. In addition, all the developed heterologous ELISAs could be used to determine parathion residue in semiquantitative or quantitative level, and their detection limitation (LOD) was around 2 ng/mL. Compared with the previous heterologous ELISA (hapten 11/5H7) with IC₅₀ of 13.3 ng/mL, a better heterologous ELISA (hapten 11/1E1) was obtained with IC₅₀ of 3.8 ng/mL, which improved the sensitivity 3.5 times. Finally, the latter was applied to parathion residue determination in spiked agricultural and environmental samples without extraction or cleanup. The average recoveries of parathion added to water, soil, cucumber, Chinese cabbage and carrot were between 80.4 % and 111.8 %. The LOD for water and soil samples was 5 ng/mL, and the LOD for cucumber, rice and corn samples was 10 ng/mL.     

Enantioselectivity of racemic metolachlor and S-metolachlor in maize seedlings

Chiral herbicides may have enantioselective effects on plants. In this study, we assessed and compared the enantioselectivity of the chiral herbicides rac-metolachlor and S-metolachlor to maize seedlings. The superoxide dismutase activity (SOD) activity of roots and stem leaves treated by rac-metolachlor was 1.38 and 1.99 times that of roots and stem leaves treated by S-metolachlor. The peroxidase activity (POD) activity of roots and stem leaves was 1.48 and 2.79 times that of roots and stem leaves treated by S-metolachlor, respectively, while the catalase activity (CAT) activity was 4.77 and 8.37 times greater, respectively. The Hill reaction activity of leaves treated by rac-metolachlor were 1.45, 1.33, and 1.14 times those treated by S-metolachlor with treatments of 18.6, 37.2, and 74.4 μM. The differences observed between treatments of rac- and S-metolachlor were significant. Significant differences in maize seedling morphology were also observed between rac- and S-metolachlor treatments. The degradation rate of S-metolachlor in roots was greater than that of rac-metolachlor. The half-lives of rac- and S-metolachlor were 80.6 and 60.3 h at 18.6 μM; 119.5 and 90 h at 37.2 μM; and 169 and 164.8 h at 74.4 μM, respectively. Using the liquid chromatography-mass spectrometry method, hydroxymetolachlor, deschlorometolachlor and deschlorometolachlor propanol were considered to be possible metabolites. We determined the enantioselective toxicity of rac- and S-metolachlor to maize and speculated on the proposed metabolic pathway of metolachlor in maize roots. These results will help to develop an understanding of the proper application of rac- and S-metolachlor in crops, and give some information for environmental safety evaluation of rac- and S-metolachlor.