Copper and Zinc in a paddy field and their potential ecological impacts affected by wastewater from a lead/zinc mine, P. R. China

As well known, at normal levels, copper and zinc are essential micronutrients for plants, animals, and humans. However, excessive Cu and Zn are toxic and disturb a wide range of biochemical and physiological processes. Using Atomic Absorption Spectrophotometer (AAS; Perkin-Elmer 3030, USA), soil and rice plant (Oryza sativa L.) samples collected from a paddy field in Lechang lead-zinc mine area, Guangdong Province, China were analyzed and their potential ecological impacts to local human and livestock were evaluated. The results showed that the paddy soils were contaminated with Cu and Zn. Both metals in soils had low bio-available fractions for paddy plants, animal and human by three chemically analytical techniques. Generally, were concentrations of copper and zinc root > straw > stalk > grain with hull > grain without hull (i.e. unpolished rice) and in the normal ranges indicating no ecological risk for local livestock and residents. All positive correlation coefficients, however, between heavy metals in rice plant and total, exchangeable (step 1 in Tessier's method established in 1979) and DTPA-extractable fractions in soils were found in this study indicating that elevated heavy metal in soils would increase long-term exposition and possible consequence of ecological hazard through food chains.     

Relationships among multiple trace elements in coastal Casuarina equisetifolia ecosystems on Hainan Island, South China

Forty-six trace elements in coastal Casuarina equisetifolia plant–soil systems at nine sampling sites on Hainan Island were analyzed using ICP-MS. The relationships among the trace elements of the same group or the same periodicity of the Periodic Table in the plants and soils were complex and no consistent patterns were found. More combinations of elements occurred with high positive correlation coefficients within the same periodicity than within the same group of the Periodic Table, and there were more high positive correlations in soils than in plants. However, there were many element combinations in Block d (transition elements) with high positive correlation coefficients in plants. Markedly high positive correlation coefficients between individual rare earth elements and Y and among Zr, Nb, Cd existed in both plants and soils. The dendrograms obtained by cluster analysis show that rare earth elements had very similar occurrence and distribution in both soils and plants. Thus, they behaved as a coherent group of elements both geochemically and biogeochemically. The transition elements were more coherent in plants than in soils.     

Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments

The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography–mass spectrometry (GC–MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC–MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment.     

Cadmium contamination in orchard soils and fruit trees and its potential health risk in Guangzhou, China

This study examines cadmium (Cd) contamination in orchard soils and fruit trees in Guangzhou, China, and assesses its potential health risk. Soils and tissues samples of three species of fruit trees were collected from three orchards. The average soil Cd concentration was 1.27, 1.84 and 0.68 mg/kg in orchards I, II, and III, respectively. The carambola (Averrhoa carambola) accumulated exceptionally high concentrations of Cd (7.57, 10.84, 9.01 and 2.15 mg/kg dw in root, twig, leaf and fruit, respectively), being 6.0-24 times and 4.0-10 times the corresponding tissue Cd in the longan (Dimocarpus longan) and wampee (Clausena lansium), respectively. Furthermore, all Cd concentrations (0.04-0.25 mg Cd/kg fw) of the fruits exceeded the tolerance limit of cadmium in foods of PR China (0.03 mg/kg fw). Our results indicate that the carambola tree has high Cd accumulation capacity and might be a Cd accumulator; and its fruit, among the three species of fruits studied, also poses the highest potential health risk to local residents.     

袋式除尘技术在我国燃煤电厂的推广应用

回顾了袋式除尘技术在我国燃煤电厂的推广应用历程,论述了我国燃煤锅炉烟气的特殊工况条件和袋式除尘器对治理电厂锅炉烟气的综合优势,总结了我国燃煤电厂对推广应用袋式除尘作出的贡献。展望在下一阶段实施新修订的《火电厂大气污染物排放标准》的过程中,袋式除尘器必将对电厂节能排减发挥更大作用。     

Fe和Fe2+对混合细菌产氢发酵的影响

在研究Fe粉剂量和Fe²⁺浓度对混合细菌产氢发酵的影响基础上,确定Fe和Fe²⁺促进混合细菌产氢能力的最佳阈值,并对乙醇型发酵菌群在不同Fe粉和Fe²⁺浓度下的产氢量和最大比产氢速率进行考察和对比.结果表明,Fe粉和Fe²⁺对乙醇型发酵菌群的产氢能力均有明显的促进作用.以葡萄糖为底物,投加Fe²⁺试验中,Fe²⁺浓度200mg/L获得最大产氢量143.7mL/g,较对照组提高32%;Fe²⁺浓度50mg/L获得单位VSS最大比产氢速率21.2 mL/(h·g),较对照组提高33%.投加单质Fe试验中,Fe粉剂量1000mg/L获得最大产氢量156.1mL/g,较对照组提高44%;Fe粉剂量500mg/L获得单位VSS最大比产氢速率23.5mL/(h·g),较对照组分别提高47%.单质Fe浓度高于50mg/L时,对发酵菌群产氢的促进作用要优于同浓度下的Fe²⁺.同时对混合细菌中铁的全量和形态分布进行了考察.     

露天矿溜槽粉尘逸散规律试验研究

为探索露天矿用溜槽系统粉尘逸散的影响因素,阐明溜槽系统运输过程中粉尘的产生机理和运移规律,从而解决溜槽系统产生的粉尘污染问题,以抚顺西露天矿为研究背景,运用相似理论,建立溜槽模型,通过单因素试验和正交试验,分别研究物料粉岩质量分数、物料含水率、溜槽倾角对溜槽运行过程中粉尘质量浓度的影响。单因素试验结果表明,粉尘质量浓度随物料粉岩质量分数、溜槽倾角增大而逐渐增大,随含水率增大而逐渐降低,溜槽底部粉尘质量浓度受影响变化幅度较大,溜槽中部和上部变化较小。溜槽粉尘质量浓度分布规律为溜槽底部粉尘产生量最大,中部次之,上方最小。溜槽底部为粉尘污染防治重点区域。正交试验结果表明,物料含水率对粉尘逸散影响最大,其次是粉岩质量分数,溜槽倾角影响最小。     

高含盐废水脱盐处理技术研究进展

综述了几种常见的高含盐废水脱盐处理技术的发展历程、工艺原理、优缺点及目前的研究进展，分析了热分离、膜分离、电渗析、离子交换、电吸附、微生物脱盐等方法的优缺点，展望了未来废水脱盐工艺的发展方向。指出：脱盐方法将根据各类水体的水质特点更加精细化；多种脱盐技术联合应用也是今后废水脱盐的发展方向。     

Horizontal lifelines – review of regulations and simple design method considering anchorage rigidity

Among the many occupational risks construction workers encounter every day falling from a height is the most dangerous. The objective of this article is to propose a simple analytical design method for horizontal lifelines (HLLs) that considers anchorage flexibility. The article presents a short review of the standards and regulations/acts/codes concerning HLLs in Canada the USA and Europe. A static analytical approach is proposed considering anchorage flexibility. The analytical results are compared with a series of 42 dynamic fall tests and a SAP2000 numerical model. The experimental results show that the analytical method is a little conservative and overestimates the line tension in most cases with a maximum of 17%. The static SAP2000 results show a maximum 2.1% difference with the analytical method. The analytical method is accurate enough to safely design HLLs and quick design abaci are provided to allow the engineer to make quick on-site verification if needed.     

High crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin for heavy metal adsorption: its characteristics and mechanisms

Environmental Science and Pollution Research - A lower expansive heavy metal adsorbent, high crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin (HCAA), has been...