Environmental and economic analysis of aluminium recycling through life cycle assessment

Aluminium is the most-used metal in the world after steel, with a wide range of applications in the industrial field owing to its physical and mechanical properties. The aim of this study was environmental and economic analysis of secondary aluminium. In particular, this study demonstrated that aluminium recycling offers many advantages to both consumers and industry:

• Increased energy savings compared to primary aluminium production;

• Recovery and reuse of raw materials for future production avoids consumption of non-renewable resources;

• Reduction in landfill waste and consequent environmental damage;

• Reduction in bauxite mining which, in turn, will reduce the socio-economic impact on populations of those countries, mainly underdeveloped, that contain mines;

• Economic advantages for Italy, the first European producer of secondary aluminium, which lacks bauxite mines and has high energy costs.

This study used the Life Cycle Assessment (LCA) method, the modified Eco-indicator 99 method for damage calculation, and the SimaPro calculation code. The study examined secondary aluminium production by ICMET, based in Reggio Emilia, Italy. The economic and environmental evaluation utilised environmental information supplied by the company.     

氟与健康的环境流行病学研究

氟是与机体健康密切相关的微量生命元素,原生环境中氟过量或缺乏均会导致机体产生疾病。氟对人类健康的影响已成为全球性的环境健康问题。综合国内外近年来的相关资料,作者概述了环境生态系物质中氟的含量、分布及化学行为,阐述了氟对机体的健康效应,分析了我国地氟病的现状,并指出了今后在氟与健康研究领域中应关注的问题。     

生物炭的土壤环境效应及其机制研究

近年来,随着土壤污染的逐渐加重以及食品安全问题的频出,生物炭作为重要的土壤改良剂以及对污染土壤修复表现出的巨大潜力引起人们的广泛关注.本文首先对国内外生物炭的土壤环境效应方面的研究以及成果进行分析总结.生物炭具有疏松多孔的性质以及巨大的表面积和阳离子交换量(CEC),可以改善土壤理化性质,能强烈吸附土壤中的污染物,降低其生物有效性和迁移转化能力;生物炭的碱性对于改良酸性土壤降低土壤中污染物的生物毒性具有很大的潜力;生物炭还可以为微生物提供生长繁殖的场所,有利于微生物对污染物的降解,但同时又可以保护被吸附的有机物免受微生物的降解,对不同的微生物影响不同;生物炭可以对蚯蚓等土壤动物的生存产生影响.在此基础上,依据生物炭的基本理化性质,对其土壤环境效应机制进行了分析.最后,从当前工作中存在的不足对今后的研究重点和方向进行了展望.     

无公害果品生产基地环境质量评价综述

文章综述了无公害果品生产现状,基地环境质量评价的指标体系和评估方法;并对基地环境质量评价发展趋势进行了预测．参26．     

Environmental variation mediates the deleterious effects of Coleosporium ipomoeae on Ipomoea purpurea

Variation in the environment is common within and between natural populations and may influence selection on plant resistance by altering the level of damage or the fitness consequences of damage from plant enemies. While much is known about how environmental variation influences the amount of damage a plant experiences, few studies have attempted to determine how variation in the environment may alter the fitness consequences of damage, particularly in plant-pathogen interactions. In this work we manipulated a rust pathogen, Coleosporium ipomoeae, in field experiments and showed that this pathogen reduced several components of fitness in its natural host plant, Ipomoea purpurea. Furthermore, we showed that the deleterious effects of C. ipomoeae were variable. We identified variation in the quality of a plant's microenvironment, the abundance of secondary enemy damage, and the length of a growing season as variable components of the environment that may influence the magnitude of damage and tolerance, causing the interaction between C. ipomoeae and I. purpurea to vary from parasitism to commensalism. Considering how environmental variation impacts the magnitude and negative fitness effects of pathogen damage is important to understanding spatially variable selection and coevolution in this and other plant-pathogen interactions.     

Environmental effects on mineral accumulation in rice grains and identification of ecological specific QTLs

Optimizing the beneficial mineral elements in rice grains is of interest for rice breeders. To study the environmental effects on mineral accumulation in rice grains, we grew a double-haploid (DH) population derived from the cross between cultivars Chunjiang 06 (CJ06, a japonica rice) and TN1 (an indica rice) under two different ecological environments (Lingshui and Hangzhou, China) and determined the content of Ca, Fe, K, Mg, Mn, P, and Zn in brown rice. These contents show transgressive variation among the DH lines. Subsequently, the quantitative trait loci (QTLs) for mineral accumulation in rice grain were mapped on the chromosomes using CJ06/TN1 population. For the 7 mineral elements investigated, 23 and 9 QTLs were identified for Lingshui and Hangzhou, respectively. Of these, 24 QTLs were reported for the first time in this study and 8 QTLs are consistent with previous reports. Only 2 QTLs for Mg accumulation have been detected in both environments, indicating that mineral accumulation QTLs in rice grains are largely environment dependent. Additionally, co-localizations of QTLs for Mn and Zn, Mg and P, and Mg and Mn accumulation have been observed, implying that these loci might be involved in the accumulation of different elements. Furthermore, the QTLs for the accumulation of Fe, K, Mg, Mn, P, and Zn were mapped to a region close to each other on chromosomes 8 and 9, suggesting that clusters of genes exist on chromosomes 8 and 9. Further characterization of these QTLs will provide a better understanding of the molecular mechanism responsible for mineral accumulation in rice grains.     

Leaching of aluminium from cookwares -- a review

Concern over the possible relation between environmental aluminium exposure and Alzheimer's disease has prompted studies of all forms of human intake of this element including that from foods. Aluminium cookware, apart from other sources of dietary aluminium, is considered to be a potential source of this metal to human beings. Various research groups have carried out aluminium leaching experiments with food, beverages and water under different experimental conditions modified by varying the level of pH, chloride, fluoride, citrate, acetate etc. The results reported by different workers show marked discrepancies in levels of leached aluminum. The apparent reason for such discrepancy in levels of aluminum leached can be attributed to factors such as non-systematic and non-uniform experimental designs, non-standard conditions maintained during the experiments and choice of method for aluminium analysis. In order to assess accurately the contribution of aluminium ingestion by human beings through aluminium cookware, the present review emphasises the need of i) standard size aluminium plates obtained from the same lot for one set of experimentations; ii) real life cooking conditions to highlight the role of various complexing species present in food e.g. citrate, oxalate, acetate, tartrate etc.; iii) role of chemistry of aluminium in presence of acidic, basic and neutral cooking medium and iv) strict analytical control in the estimation of aluminium. Results of a systematic study by the authors conducted on the abovementioned lines are also described.     

Simple assessment of the reactive aluminium in sediments

The mobility of aluminium in sediments was evaluated through a one-step extraction with a strong chelating agent. Single and sequential extraction procedures for the extraction of Al were applied to four sediments from a polluted region. A single-step extraction with 0.05 mol L⁻¹ ethylenediaminetetraacetic acid (EDTA) was used, and compared with a standardized SEP as reference. The Al contents extracted into Na₂EDTA were in good agreement with the sequential extraction that yeilds mobile and potentially mobile portion of Al. Extracted EDTA contents make up more than 70% of the first-three-step sum of the five-step extraction procedure. Thus, Na₂EDTA extraction of Al could be applied to assess aluminium mobility changes in sediments and soils.     

Influence of soil-extractable aluminium and pH on the uptake of aluminium from soil into the soybean plant (Glycine max)

The effects of soil pH and other soil properties on the uptake of AI by soybean plants have been investigated in a greenhouse experiment. Six soils were compared that were developed over six contrasting bedrock types ranging widely in their AI content and other chemical and physical characteristics, namely Oxford Clay, Chalk, Lower Lias Clay, Devonian Shale, Granite and Lower Greensand. Soil pH varied naturally between soil types and each soil was also amended to give two other pH levels using elemental sulphur and/or calcium carbonate. AI concentrations in various parts of the soybean plants were determined by ICP-AES after acid digestion. The AI solubility in the soils and hence its availability to the plants was estimated using a number of different reagents designed to extract different forms of AI. The AI concentration measured in the soybean leaves was found to be predicted most accurately by the ‘available’ AI extracted from soils by 0.02 M CaCl₂. The relationship appears to the linear, with a correlation coefficient of 0.97 (p <0.01). The AI content of the leaves increases with decreasing soil pH. The relationship is non-linear with a marked increase in leaf AI for soils with pH <4.4. The amounts of ‘plant-available’ AI in the soils extracted with 0.02 M CaCl₂ was much less than that extracted with 0.05 M EDTA, although both increased markedly with decreasing soil pH. The amount of AI measured in the soybean plants was directly related to both the ‘available’ forms of AI in the soils, and also to the pH of the soils. Soil pH was identified as a major factor that controls the uptake of Al from soil into the soybean plant.     

Review of epidemiologic studies of aluminium and neurological disorders

The epidemiological study of neurological disorders is just beginning and should he continued because of the potential public health impact of these diseases on society. The most important contribution of epidemiological research is the identification of risk factors, and specific disease entities, such as Alzheimer's disease, should be studied.Ecological analysis of geographical data have associated a small increase in mortality from Alzheimer's disease and dementia with the aluminium content of drinking water. These results must necessarily be interpreted with caution because serious errors may result from inferences based on ecological analysis,e.g. the ecologic fallacy.Potential risk factors for Alzheimer's disease have been studied in case-comparison epidemiology studies conducted in Italy, Massachusetts, Colorado, Minnesota and North Carolina, but only two studies have considered aluminium exposure, through the use of antacids. Although no increased risk was found to be associated with aluminium exposure, only a small number of individuals in the studies reported antacid use, and the studies had an extremely limited statistical power to detect an association.Additional analytical epidemiology studies, either cohort or case-comparison, are required to better describe the possible relationship between aluminium and Alzheimer's disease. These studies should be designed according to well-established epidemiological principles, be conducted with no selection bias and minimum observation bias, consider potential confounding and modifying factors, and have sufficient statistical power to enable detection of low relative risks.     

Nitrogen-fixation by cyanobacteria associated withCodium fragile (Chlorophyta): Environmental effects and transfer of fixed nitrogen

N₂-fixation associated with the green macroalgaCodium fragile subsp.tomentosoides (van Goor) Silva from Long Island, New York, USA, was attributable to several species of endophytic cyanobacteria. Rates of N₂-fixation ranged from 0.03 to 3.2µg N g^–1 dry wt h^–1 in freshly collected plants from several sites. Growth of the cyanobacteria appeared to be light-limited, due to the transmission of only 5 to 10% of incident light through the pigmented surface-layer of the macroalga. Daily irradiance was the most important factor determining both abundance of cyanobacterial cells and rate of N₂-fixation. The rate was also affected by instantaneous irradiance, and increased twofold from dark to ambient surface irradiance. Rates were reduced at low temperature (8°C) but showed no temperature effect between 12° and 26°C. External concentrations of dissolved inorganic nitrogen (DIN) up to 20µM did not influence N₂-fixation rate, but long-term exposure to 60µmol l^–1 d^–1 of NH ₄ ⁺ caused a reduction in the rate. InC. fragile grown under high daily irradiance and low external DIN concentration, ~50% of the assimilated-N was attributable to N₂-fixation. However, chlorophyllb extracted from plants grown with¹⁵N₂ showed an atom % excess¹⁵N of less than 0.1, suggesting that only a small proportion of the bacterially fixed-N was transferred to the seaweed. The association betweenC. fragile and its endophytic cyanobacteria appears to be based primarily on microhabitat suitability, rather than mutual metabolic dependence. It is doubtful that N₂-fixation by cyanobacteria is important to the ecological success of this seaweed species.     

天津污灌区土壤重金属污染环境质量与环境效应

污水作为天津解决农业用水不足的手段已经有几十年的历史。文章分析了污灌区土壤一作物系统中Cd、Hg、As、Cu、Pb、Zn和Cr等有毒重金属的质量分数，利用单因子污染指数法和加权综合污染指数法进行污染评价。评价结果表明污灌区土壤受到了严重污染，主要重金属污染元素为Cd、Hg；农作物中的主要超标元素为Cd、As。因此，污灌区重金属污染土壤的修复工作迫在眉睫。     

Unusual sources of aluminium and heavy metals in potable waters

Aluminium in water supplies derives from natural sources and from the use of Al₂(SO₄)₃ in water treatment. Heavy metals such as Pb, Cu, Zn and Cd can be added to water from pipework and solder. However, it is apparent that AI and other metals in potable waters can derive from deposits on pipe walls which can be subsequently mobilised when the supply and/or treatment process is changed. Concentrations of Al in domestic supply water of the Llanbrynmair area have been shown to increase from 1 g to 50 g L^–1 during its 18 km journey along the water main. Similarly, Pb concentrations in a public building in the Aberystwyth area are found to be extremely elevated due to the metal's mobilisation from encrustations occurring on the copper pipework.     

Environmental geochemistry of technetium

Technetium-99 (⁹⁹Tc) is a radioactive isotope with a half-life of 2.13 × 10⁵ year. ⁹⁹Tc is a major radionuclide contaminant of concern for the world. Therefore, detailed understanding of ⁹⁹Tc environmental chemistry is important for protecting human and ecological health. Here, we review the aqueous geochemistry of ⁹⁹Tc, focusing on chemical properties and behavior of ⁹⁹Tc in the hydrosphere and pedosphere. We describe the general chemistry of Tc including coordination chemistry, isotope chemistry and solid-state chemistry. Then we present anthropogenic and indigenous sources of ⁹⁹Tc and their environmental distribution. We also discuss the radiotoxicity of ⁹⁹Tc and the use of ⁹⁹Tc for medical purpose. Tc biogeochemistry is described through sorption and desorption reactions at the mineral–water interface, thermodynamic of surface complexation, abiotic and biotic redox reaction of Tc(VII). Finally, we summarize the ⁹⁹Tc remediation technologies including cement waste forms, natural remediation, vitrification, nuclear waste transmutation.     

Environmental effects and risk control of antibiotic resistance genes in the organic solid waste aerobic composting system: A review

• ARGs were detected in livestock manure, sludge, food waste and fermentation dregs. • The succession of microbial community is an important factor affecting ARGs. • Horizontal transfer mechanism of ARGs during composting should be further studied. Antibiotic resistance genes (ARGs) have been diffusely detected in several kinds of organic solid waste, such as livestock manure, sludge, antibiotic fermentation residues, and food waste, thus attracting great attention. Aerobic composting, which is an effective, harmless treatment method for organic solid waste to promote recycling, has been identified to also aid in ARG reduction. However, the effect of composting in removing ARGs from organic solid waste has recently become controversial. Thus, this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years. ARGs in organic solid waste could spread in different environmental media, including soil and the atmosphere, which could widen environmental risks. However, the conventional composting technology had limited effect on ARGs removal from organic solid waste. Improved composting processes, such as hyperthermophilic temperature composting, could effectively remove ARGs, and the HGT of ARGs and the microbial communities are identified as vital influencing factors. Currently, during the composting process, ARGs were mainly affected by three response pathways, (I) “Microenvironment-ARGs”; (II) “Microenvironment-microorganisms-ARGs”; (III) “Microorganisms-horizontal gene transfer-ARGs”, respectively. Response pathway II had been studied the most which was believed that microbial community was an important factor affecting ARGs. In response pathway III, mainly believed that MGEs played an important role and paid less attention to eARGs. Further research on the role and impact of eARGs in ARGs may be considered in the future. It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.     

环境技术评价

第7期 1998年 因特网咖啡屋决策信息途径 人们一再强调对便利技术合作、评价和转让的良好信息机制的需要.针对这种需求,联合国环境署工业与环境中心(UNEP IE),与联合国环境署国际环境技术中心(UNEP IETC)、联合国贸易与发展会议(UNCTAD)和联合国工业与发展组织(UNIDO)合作,已经开发了几种以电子为基础的模块,以提供关于与许多工业生产过程相联系的特定的和更广义的环境问题的信息.