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  • 1
    Type of Medium: Book
    ISBN: 0869890778
    Series Statement: Special Publication / South African Association for Marine Biological Research, Oceanic Research Institute 4
    DDC: 333.95/613/0968758
    Language: English
    Note: At head of title: South African Association for Marine Biological Research. Oceanographic Research Institute , April 1997"--Cover , Includes bibliographical references
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry 50 (1958), S. 649-656 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 56 (1952), S. 671-672 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 33 (1995), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Four years of detailed ground-water monitoring at a newly installed, seasonal-use, domestic septic system located on poorly buffered (CaCO3 equivalent content ≤ 1.6 wt.%) lacustrine silt, has revealed the development of an acidic ground-water plume. Acid, generated by the partial oxidation of effluent NH4+ dissolved organic carbon (DOC), and possibly sulfide minerals present in the sediment, has resulted in a distal plume core zone with pH values in the range of 4.4 to 5.0. The acidic zone, where NH4+ does, however, persist (〉 2 mg/1, as N) and where DOC remains elevated (6–13 mg/1), is associated with high average concentrations of the trace metals Fe (4.7 mg/1), Al (1.9 mg/1), and Mn (3.6 mg/1). Attenuation of nitrogen along the plume core flowpath is indicated by a decrease in the N/ Cl− ratio from an effluent value of 1.7, to a plume value of only 0.5 after 4 m of subsurface flow. Increased SO42− levels observed in the zone of N depletion suggest that attenuation can be at least partly attributed to reduction of plume NO3− by oxidation of reduced S present in the sediment. PO43− has not migrated significantly beyond the infiltration bed gravel layer, demonstrating that PO43− mobility is limited in these sediments (retardation factor 〉 10).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 436 (1984), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 22 (1993), S. 0 
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Biopsies of non-ulcerated oral mucosa from 13 patients with oral lichen planus and 12 patients with leukoplakia were immunohistochemically stained using monoclonal antibodies to pan T, pan B, T helper and T suppressor/cytotoxic cells and the stained lymphocytes enumerated using an image analyser. The results show the preponderance of T cells infiltrating both oral lichen planus and leukoplakia. The T helper: T suppressor/cytotoxic cell ratio was the same (1:2) for both oral lichen planus and leukoplakia. A similar proportion of T suppressor/cytotoxic cells was found infiltrating the epithelium. These data indicate that T cell subset analysis is of no value in distinguishing oral lichen planus from other oral keratoses.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 33 (1995), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: A new alternative septic-system design is presented utilizing reactive porous media barriers for passive in situ attenuation of NO3−. The reactive material consists of solid organic carbon (sawdust) which promotes NO3- attenuation by heterotrophic denitrification. Four field trials are discussed demonstrating two barrier configurations: as a horizontal layer positioned in the vadose zone below a conventional septic-system infiltration bed and as a vertical wall intercepting a horizontally flowing downgradient plume. During one year of operation both barrier configurations have been successful in substantial attenuation (60 to 100%) of input NO3- levels of up to 125 mg/1 as N. The horizontal layer configuration can be readily installed during the construction of new infiltration beds, whereas the vertical wall configuration may be more appropriate for retrofitting existing septic systems where NO3- contamination has already occurred. The layer configuration allows the flexibility of constructing the barrier in the vadose zone by using coarse silt or fine sand matrix material that has the ability to remain tension-saturated, and thus anaerobic, even when positioned above the water table.Advantages of the barrier system are that it is simple to construct, no surface structures or additional plumbing are necessary, and treatment is passive requiring no energy consumption and little or no maintenance. Mass balance calculations and preliminary results suggest that conveniently sized barriers have the potential to last for decades without replenishment of the reactive material.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 29 (1991), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Distinct plumes of septic system-impacted ground water at two single-family homes located on shallow unconfined sand aquifers in Ontario showed elevated levels of Cl−, NO3−, Na+, Ca2+, K+, alkalinity, and dissolved organic carbon and depressed levels of pH and dissolved oxygen. At the Cambridge site, in use 12 years, the plume had sharp lateral and vertical boundaries and was more than 130 m in length with a uniform width of about 10 m. As a result of low transverse dispersion in the aquifer, mobile plume solutes such as NO3− and Na+ occurred at more than 50 percent of the source concentrations 130 m downgradient from the septic system. At the Muskoka site, in use three years, the plume also had discrete boundaries reflecting low transverse dispersion. After 1.5 years of system operation, the Muskoka plume began discharging to a river located 20 m from the tile field. Almost complete NOs attenuation was observed within the last 2 m of the plume flowpath before discharge to the river. This was attributed to denitrification occurring within organic matter-enriched riverbed sediments.The very weakly dispersive nature of the two aquifers was consistent with the results of recently reported natural-gradient tracer tests in sands. Therefore, for many unconfined sand aquifers, the minimum distance-to-well regulations for permitting septic systems in most parts of North America should not be expected to be adequately protective of well-water quality in situations where mobile contaminants such as NOs are not attenuated by chemical or microbiological processes.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 22 (1984), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: A zone of contaminated ground water has been identified in an unconfined sand aquifer adjacent to a pit into which spent pulp liquor was intermittently discharged from 1970 to 1979. A network of multilevel sampling, bundle-type piezometers was installed. Up to seven depthspecific sampling points were incorporated into each piezometer providing a cost-effective means for three-dimensional mapping of hydraulic head and water quality in the unconfined sand aquifer. Ground-water samples retrieved from this network showed an area of contamination 900 m long, 400 m wide, and more than 25 m deep. This plume is dispersed about the ground-water flow lines passing beneath the waste disposal pit, and it terminates at a vigorous ground-water discharge area located 800 m from the pit.The contaminated ground water is characterized by elevated concentrations of sodium (3,000 mg/1), chloride (590 mg/1), alkalinity (2,700 mg/1), total organic carbon (2,000 mg/1), chemical oxygen demand (10,800 mg/1), biological oxygen demand (2,000 mg/1), tannin and lignin (780 mg/1), and lower sulphate (1 mg/1) compared to background ground waters in the area. The apparent rate of sodium migration is more than 50 m/yr and is close to the average linear ground-water velocity. Removal of some organic matter by biological transformation has produced the increased alkalinity in the contaminated ground water and somewhat reduced pH. Tannin and lignin are relatively inert compared to other organic compounds found in the waste liquor. Extremely low sulphate levels occurring in the highly contaminated ground waters indicate the existence of conditions favorable for microbially-mediated sulphate reduction.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 34 (1996), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Four hundred ground-water sampling points were used to delineate a plume in an unconfined sand aquifer at a 44 year old septic system servicing a school in Ontario, Canada. A bromide tracer test indicated a residence time of one to two weeks for sewage effluent in the 1.6 meter unsaturated zone beneath the tile bed. This is sufficient time for the oxidation of all nitrogen to nitrate to be complete and for the content of dissolved organic carbon to decrease from about 19 mg/l in the septic tank to about 1 mg/l at the water table. The 15m wide plume core emanates more than 110 meters downgradient of the tile bed, has detectable dissolved oxygen, high nitrate (20–120 mg/l as N), chloride (42–209 mg/l), sodium (34–101 mg/l), calcium (120–249 mg/l), and above background sulphate, and potassium. Ground-water flow velocity at this site is rapid (100 m/yr); thus the mapped extent of the plume (110 m) represents about one year effluent loading. Phosphate (PO43-) concentrations at the water table (∼ 1–2 mg/l as P) appear to have reached steady state at values significantly lower than that of the effluent (9 mg/l as P). Steady-state concentrations suggest that mineral precipitation reactions control attenuation in the unsaturated zone. A comparison of phosphate sorbed (74 mg/kg) and total P in the soil (1000 mg/kg) suggests that precipitation is a more important process in the unsaturated zone than is sorption. PO43- levels in the plume, however, remain elevated (0.3–1.8 mg/l as P) relative to background levels in ground water (〈0.01 mg/l as P) up to 75 meters away from the tile bed. This migration distance of PO43- in ground water is greater than that observed at other younger septic system sites. The extent of the plume at this site suggests that long-term PO43- migration in the ground-water zone may be controlled by adsorption processes that allow slow but progressive advancement of PO43-.
    Type of Medium: Electronic Resource
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