Organic contaminants

Xem 1-20 trên 108 kết quả Organic contaminants
  • Hydrogen peroxide is a strong oxidant that can be injected into a contaminated zone to destroy petroleum contaminants. When injected to groundwater, hydrogen peroxide is unstable, and reacts with organic contaminants and subsurface materials. It decomposes to oxygen and water within hours of its introduction into groundwater generating heat in the process. Peroxide is typically shipped to a remediation site in liquid form at dose concentrations ranging from five percent to 50 percent by weight.

    pdf240p cao_can 29-12-2012 28 8   Download

  • Surface water treatment is a controversial issue. A healthy balance between possible risks, such as immediate microbiological contamination and long-term carcinogenic effects due to dsinfection byproducts, and the treatment costs is required. Another issue of concern relates to drinking water standards, whch seem unreasonably strict in some countries and practically absent in others. The price people are required to pap for their water varies with the standards.

    pdf213p 951628473 07-05-2012 38 19   Download

  • Significant advances in subsurface containment technology occurred in the 1990s, both with the improvement of the technology and the broader acceptance and applications as a measure for environmental remediation. Since 1995, the U.S. Department of Energy (USDOE), U.S. Environmental Protection Agency (USEPA), and DuPont have collaborated on a series of organized efforts to advance this technology. In that year, these collaborators sponsored an international expert workshop that led to the publication of the first major book on containment technology.

    pdf374p crazy_sms 10-05-2012 34 13   Download

  • Controlled oxidation is increasingly being practiced using solid peroxides, pH modifiers, and catalysts that promote the generation of free radicals. This new approach moderates the rate of dissolution and peroxide generation, which in turn controls that rate of reaction between peroxide and the petroleum contaminants. The use of slurried peroxides creates the opportunity to release oxidants and oxygen over a longer period, which can promote subsequent aerobic remediation.

    pdf182p cao_can 29-12-2012 37 6   Download

  • There is currently no independent authoritative statement on the nature and importance of differences in content of nutrients and other nutritionally relevant substances (nutrients and other substances) in organically and conventionally produced foodstuffs. This systematic review of the available published literature was designed to seek to determine the size and relevance to health of any differences in content of nutrients and other substances in organically and conventionally produced crops and livestock products.

    pdf209p ut_hai_can 29-12-2012 26 5   Download

  • Estuaries are areas of high productivity, crucial in the life histories of many fish, invertebrates, and birds, for example, and the sustainability of estuarine biodiversity is vital to the ecological and economic health of coastal regions. On the other hand, estuarine ecosystems are exposed to toxic anthropogenic effluents transported by rivers from remote and nearby conurbations and industrial and agricultural concerns.

    pdf370p phoebe75 01-02-2013 16 5   Download

  • There are, actually, no formal Swedish regulations for organic contaminants in sludge. There is an informal agreement between the Swedish EPA, the Farmers Union and the Water and Wastewater Association which includes the recommendations in table 3.1-1. These agreements are based more on practical experience than on scientific data. Sweden also used to have a recommended limit value for toluene, but this has been omitted (WALLGREN 2001).

    pdf53p ut_hai_can 29-12-2012 32 4   Download

  • Petroleum contaminant decomposition and in-situ destruction may be accomplished using chemical oxidation technologies. In contrast to other remedial technologies, contaminant reduction can be seen in short time frames (e.g., weeks or months). As discussed in this chapter, a variety of chemical oxidants and application techniques can be used to bring oxidizing materials into contact with subsurface contaminants to remediate the contamination.

    pdf112p cao_can 29-12-2012 25 4   Download

  • Land contamination has been recognised as a challenge to present and future generations resulting from previous industrial and waste disposal practices. This book is a result of the authors’ desire to make sure that the risks from land contamination are effectively understood and adequately managed in a context of wise stewardship of resources. It is written for those embarking on their journey in contaminated land management – those final year undergraduate and postgraduate students pursuing an option in contaminated land.

    pdf251p phongmt1993 08-08-2013 17 3   Download

  • Difficulty in accessing ground water without disturbing ground-water flow patterns, chemistry, microbiology, and the physical and chemical makeup of formation materials has made accurate characterization of in situ ground-water conditions a very challenging task.

    pdf308p 951628473 07-05-2012 59 29   Download

  • The primary purpose of preparing this edition is to provide an update. In the 14 years since the first edition was published, ecological risk assessment has gone from being a marginal activity to being a relatively mature practice. There are now standard frameworks and guidance documents in the United States and several other countries. Ecological risk assessment is applied to the regulation of chemicals, the remediation of contaminated sites, the importation of exotic organisms, the management of watersheds, and other environmental management problems....

    pdf0p 951628473 07-05-2012 67 27   Download

  • Difficulty in addressing contamination in low permeability soils may be alleviated to some degree by controlled pneumatic or hydraulic fracturing of the soil. However, engineered hydraulic fractures generally cannot be spaced more closely than about 5 feet, which means that chemical oxidants must still penetrate a substantial thickness of low permeability soil to come into contact with the contamination. Deep soil mixing with large diameter drill augers is the most effective method currently available to increase contact between adsorbed contaminants and the oxidants.

    pdf408p cao_can 29-12-2012 28 11   Download

  • Chemical oxidation technologies are predominantly used to address contaminants in the source area saturated zone and capillary fringe. Cost concerns can preclude the use of chemical oxidation technologies to address large and dilute petroleum contaminant plumes. More frequently, chemical oxidation technologies are employed to treat smaller source areas where the petroleum mass is more concentrated.

    pdf477p cao_can 29-12-2012 25 10   Download

  • Due to their low aqueous solubilities, the PCBs and PAHs lay on the surface of soils and waters. PCBs and PAHs adsorb strongly to the organic fraction of soils (Girvin & Scott, 1997; Hiller et al., 2011). Soils contaminated with PCBs and PAHs are transported directly or indirectly by rivers to the water reservoir and are subsequently converted into the bed sediments. Therefore, soils could be considered as the primary sinks for these organic contaminants. PCBs and PAHs are persistent in the environment, resistant to degradation process, and accumulate in food chain.

    pdf20p lulanphuong 28-03-2012 56 9   Download

  • This book proposes a framework for a national-scale program to monitor changes in mercury concentrations in the environment following the reduction of atmospheric mercury emissions. The book is the product of efforts initiated at a workshop held in Pensacola, Florida, in September 2003, involving more than 30 experts in the fields of atmospheric mercury transport and deposition, mercury cycling in terrestrial and aquatic ecosystems, and mercury bioaccumulation in aquatic food webs and wildlife.

    pdf218p 951628473 07-05-2012 30 8   Download

  • Bioavailability, Biotransformation, and Fate of Organic Contaminants in Estuarine Animals - Một thành phần quan trọng của nghiên cứu đánh giá rủi ro sinh thái trong các đại dương và cửa sông bao gồm các đặc tính của sự tiếp xúc của động vật cửa sông để chất gây ô nhiễm. Dữ liệu về sinh khả dụng, sự thu hút, tích tụ, và loại bỏ

    pdf30p hoathietmoclan 03-10-2011 33 7   Download

  • Established in 1995, the Interstate Technology & Regulatory Council (ITRC) is a state-led, national coalition of personnel from the environmental regulatory agencies of some 40 states and the District of Columbia; three federal agencies; tribes; and public and industry stakeholders. The organization is devoted to reducing barriers to, and speeding interstate deployment of, better, more cost-effective, innovative environmental techniques.

    pdf172p lulanphuong 22-03-2012 43 7   Download

  • Experts working in diverse areas of coastal and estuarine risk assessment contributed to this first volume of the CRC Press Environmental Risk Series. Contributors were asked to address a comprehensive series of important topics including the regulatory context for coastal and estuarine risk assessment, emerging contaminants of concern, effects to marine mammals, bioavailability and exposure of marine organisms to inorganic and organic contaminants, and effects of contaminants on ecological entities ranging from biomolecules to landscapes....

    pdf0p 326159487 17-05-2012 24 7   Download

  • Soil reactivity with chemical oxidants is also important when considering the costs of the use of chemical oxidation. Excessive loss of a chemical oxidant that is reacting with organics in soil, instead of reacting with the contaminants, may preclude the use of the technology as an economically viable approach to site remediation. Different chemical oxidation technologies are most appropriate for particular hydrogeologic conditions. For example, Fenton’s Reagant may not be ideal for groundwater with high concentrations of carbonate.

    pdf158p cao_can 29-12-2012 27 7   Download

  • Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4°C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample.

    pdf0p cao_can 02-01-2013 27 7   Download

CHỦ ĐỀ BẠN MUỐN TÌM

Đồng bộ tài khoản