Mobility of Cd and Cu in formulated sediments coated with iron hydroxides and/or humic acids: a DGT and DGT-PROFS modeling approach

The diffusive gradients technique in thin films (DGT) was used to investigate the kinetic resupply of Cd and Cu to pore water from the solid phase. For the sake of simplification, experiments were performed using formulated sediments that differed in the presence or absence of humic acids (HA) and/or of iron hydroxides (i.e., goethite and ferrihydrite). The effects of the time after the contamination of the solid phase (aging effect) on formulated sediments that were coated with goethite and HA and spiked with Cd were also evaluated. Kinetic DGT results were interpreted using the newly developed, multi-compartmental model DGT-PROFS.Due to Cu humate formation, the addition of HA slightly increased the Cu concentration in the pore water independent of the effect of the iron hydroxide coating on the formulated sediments and slightly decreased that of Cd. The impact of 8-190 d of aging resulted in a significant decrease in the Cd concentration of the pore water over an increasing incubation time.Modeling our results with DGT-PROFS led to the following conclusions concerning the impact of HA and iron hydroxides on Cd and Cu availability. First, in the presence of HA and absence of iron hydroxides, Cd is associated mainly with weak sites, while Cu is bound to strong sites. Similarly, in the presence of both iron hydroxides and HA, Cu appeared to be more heavily associated with the strong sites than did Cd. When the incubation time increased from 8 to 190 d, a proportion of Cd initially adsorbed onto weak sites transferred to the strong sites, suggesting that the adsorption of Cd on sediments is controlled partially by slow kinetic processes.     

Technologically enhanced 210Pb and 210Po in iron and steel industry

Iron and steel manufacture has been ranked as the largest industrial source of environmental contamination in the USA; the wastes generated in their production processes contain heavy elements that can be a source of contamination, and natural radionuclides that can produce an occupational and/or public radiological impact. In this work the potential occupational effective dose rate (μSv/y) due to inhalation in four integrated steel-making factories from Egypt has been evaluated, by assuming a well defined scenario and with basis in the ²¹⁰Pb and ²¹⁰Po activity concentrations determined in ore and wastes collected in the aforementioned factories. Activity concentrations, in Bq/kg, of ²¹⁰Pb and ²¹⁰Po, and leachable Pb and Fe were measured using gamma-ray spectrometry based on HPGe detector, alpha particle spectrometry based on PIPS detector, and inductively coupled plasma-mass spectrometry (ICP-MS). Levels of ²¹⁰Pb and ²¹⁰Po in the range of <DL-4238 and 1-5660 Bq/kg, respectively, were found. According to the assumed scenarios, the occupational exposures by inhalation are much lower than the recommended annual effective dose limit, although the environmental impact due to waste storage and/or use should be considered based on case by case evaluation.     

Lipid peroxidation in the presence of iron oxides

Exposure to iron oxides dusts may lead to lung cancers among exposed population. To evaluate the involvement of iron‐containing particles in lipid peroxidation by production of reactive oxygen species, hematite, magnetite (iron oxides), and crocidolite (asbestos compound) were tested. The peroxidation was followed by the evaluation of some degradation products of lino‐lenic acid. In a buffered medium, magnetite is higher active than hematite. The addition of an iron chelator (EDTA) or of a reducing agent (ascorbate) in this medium enhances the activity of hematite and magnetite, and the combination of both EDTA and ascorbate increases their activity. Crocidolite is the most active whatever the medium. The appearance of the EDTA‐iron‐oxygen complexes related to the reactivity of these oxides is postulated. These results suggest that the oxidizing activity triggered by hematite and magnetite, in a medium containing an iron chelator and a reducing agent, may lead to damages in biological medium.     

立式加热炉节能减排可行性研究

大庆油田原稳装置采用立式加热炉,烟气中存在大量的废热。在现有装置运行中,烟气直接排放,浪费了大量的热量。通过在实验装置中可回收废热资源及废热回收技术研究,采用热管技术回收烟气废热,用于预热空气,不仅会节能降耗,给企业创造可观的经济效益,还会减少大气污染,创造良好的社会效益。     

The carajas iron ore project: The strategy of a third world state- owned enterprise in a depressed market

This paper describes how the Carajas iron ore project was set up in February 1985 at a time of deep recession in the iron ore and steel industries. Development of the project was met with much criticism, mainly from North American steel makers, who argued that the project would only be successful through the support of a Third World government, highly dependent on foreign exchange, without any consideration being given to its economic feasibility or to the fundamentals of the market. The authors explain why the World Bank took the step of setting up the project and how its development can be partly explained by the interests of the Japanese and European steel makers. The role of the Brazilian government is explained and the authors conclude that the relatively low rate of investment anticipated by the project will be overshadowed by the high gains in foreign exchange.     

DISCHARGE CHARACTERISTICS OF PERFORATED PIPE FOR USE IN INFILTRATION TRENCHES1

ABSTRACT: Infiltration trenches are an effective stormwater management alternative for the control of urban runoff from small areas. Perforated pipes buried within the gravel of an infiltration trench are used to distribute the inflowing runoff along the length of the trench. Laboratory tests are described that characterize the hydraulics of the orifices in perforated pipes. The results show that the steady-state exfiltration of water from the pipe into a surrounding gravel trench can be described by the orifice equation.     

除尘系统加接新支管的理论和实践

对于一个现有的除尘系统,若其除尘器、通风机的工作能力有足够的富余量,则可以在该系统管网上加接新的支管,来治理新的扬尘点。     

架空管道震害预测实用方法的研究

根据震害调查分析和试验研究结果,建立了由环境因素和管道结构参数组成的,对架空管道震害预测进行二级多因素模糊综合评判的方法。文中给出了计算、评价构成二级评判因素地震烈度、场地类型、工作状态和结构种类各档次正态模糊数范数ａｋ的参数和对实际情况如何确定的方法。本文为面广量大的已建架空管道的震害预测工作提供了一套科学性强,方便实用的计算方法。     

对铁碳处理硝基酚废水的研究

铁碳降解水中难降解有机污染物的影响因素、最佳工艺参数及处理效果;初步探讨了氧化降解污染物的作用机理;通过分析污染物降解的中间产物,提出了污染物降解的可能途径.探讨了pH、铁碳用量、温度以及锰矿物的粒径等对处理效果的影响,在最佳的工艺条件下,CODCr的去除率达到95%以上,TOC测定表明：大部分硝基酚被氧化降解为H2O和CO2.对硝基酚的降解途径主要是微电解将对硝基酚还原为对氨基酚,对氨基酚在酸性条件下被软锰矿氧化为H2O和CO2做探索性研究.     

Environmental impacts of iron ore tailings—The case of Tolo Harbour,Hong Kong

Disposal of iron ore tailings along the shore of Tolo Harbour, Hong Kong has altered the adjacent environment. Due to the ever-expanding population, the vast development of various industries, and the lack of sanitary control, the existing pollution problem of Tolo Harbour is serious. The iron ore tailings consist of a moderate amount of various heavy metals, e.g., copper, iron, manganese, lead, zinc, and a lower level of macronutrients. A few living organisms have been found colonizing this manmade habitat. Higher metal contents were also found in the tissue ofPaphia sp. (clam);Scopimera intermedia (crab);Chaetomorpha brychagona (green alga);Enteromorpha crinita (green alga); andNeyraudia reynaudiana (grass). The area can be reclaimed by surface amelioration using inert materials, soils, or organic substrates, and by direct seeding, using nontolerant and tolerant plant materials. Reclamation of the tailings would improve the amenity of the adjacent environment and also mitigate pollution escaping to the sea.