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  • 1990-1994  (3)
  • 1,3-propanediol  (1)
  • 45Ca  (1)
  • Fly ash  (1)
  • business ethics
Materialart
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Environmental management 15 (1991), S. 797-808 
    ISSN: 1432-1009
    Schlagwort(e): Created cattail wetlands ; Wetland mitigation ; Typha ; Fly ash ; Pollution abatement ; Landfills ; eastern Massachusetts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract In order to balance pressures for land-use development with protection of wetland resources, artificial wetlands have been constructed in an effort to replace lost ecosystems. Despite its regulatory appeal and prominent role in current mitigation strategies, it is unclear whether or not created systems actually compensate for lost wetland resources. Mitigation predictions that rely on artificial wetlands must be analyzed critically in terms of their efficacy. Destruction of wetlands due to burial by coal fly ash at a municipal landfill in Danvers, Massachusetts, USA, provided an opportunity to compare resulting growth of created cattail (Typha) marshes with natural wetland areas. Once the appropriate cattail species was identified for growth under disturbed landfill conditions, two types of artificial wetlands were constructed. The two systems differed in their hydrologic attributes: while one had a surface water flow characteristic of most cattail wetlands, the second system mimicked soil and water conditions found in naturally occurring floating cattail marshes. Comparison of plant growth measurements for two years from the artificial systems with published values for natural cattail marshes revealed similar structure and growth patterns. Experiments are now in progress to investigate the ability of created cattail marshes to remove and accumulate heavy metals from polluted landfill leachate. Research of the type reported here must be pursued aggressively in order to document the performance of artificial wetlands in terms of plant structure and wetland functions. Such research should allow us to start to evaluate whether artificial systems actually compensate for lost wetlands by performing similar functions and providing the concomitant public benefits.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-5117
    Schlagwort(e): 226Ra ; 45Ca ; calcium ; magnesium ; accumulation ; turtle ; uranium mining
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Snapping turtles Elseya dentata (Gray) from Magela Creek, Northern Territory, were exposed under laboratory conditions for up to 30 days to waters resembling the inorganic composition of Magela Creek water during the Wet season, with background and elevated Ca and Mg concentrations, that were labelled with 226Ra and 45Ca. The resulting concentrations of 45Ca in muscle, skin, gut, liver, shell bone and leg bone of E. dentata equilibrated or approached equilibrium by 12–18 days. Among the experiments, the concentrations of 45Ca in all six tissues were inversely related to turtle mass. An increase in the Ca water concentration by a factor of 15 increased the 45Ca concentration in all six tissues. The arithmetic factors of increase in the concentration in each tissue were proportional or more than proportional to the factor of increase in Ca water concentration; this factor was highest for muscle tissue (26.6). An increase in the Mg water concentration by a factor of 48 reduced the 45Ca concentration in all tissues except skin where it increased. The concentration of 226Ra in each tissue (except the gut) was positively related to its 45Ca concentration and inversely related to turtle mass in muscle, skin and liver. With the exception of the skin, the increased Ca water concentration did not reduce the 226Ra in the tissues but increased the 226Ra concentration in bone and muscle. The increased Mg water concentration had an inverse effect on the 226Ra concentrations in all tissues except shell. With the exception of the skin the effects of increased Ca and Mg water concentrations and turtle size on 226Ra concentrations in the tissues of E. dentata were similar to their effects on 45Ca tissue concentrations, indicating the similar metabolic behaviour of 226Ra and 45Ca in E. dentata. Exposures of the species Elseya latisternum (Gray), Emydura signata (Ahl) and Chelodina longicollis (Shaw), which are the same or closely related to species reported to occur in Magela Creek, to 45Ca-labelled Sydney tap water for 7 days demonstrated their ability to also accumulate 45Ca from their aquatic medium. The patterns of 45Ca concentrations in the tissues of these species indicated that they were inversely related to turtle mass, as demonstrated in E. dentata. The concentrations of 45Ca accumulated in the tissues were also comparable to those found in single specimens of E. dentata and E. victoriae (Gray) that were exposed for 7 days to simulated Magela Creek water. The data also indicated the larger long-necked C. longicollis accumulated less 45Ca per gram of tissue than similar-sized, short-necked species E. signata and E. latisternum, suggesting that long-necked turtles from Magela Creek would accumulate less 226Ra from their aquatic medium than similar-sized short-necked species. The capacity of E. dentata to accumulate 226Ra from the aquatic medium is about two orders of magnitude less than that of the tissue of the freshwater mussel Velesunio angasi (Sowerby) exposed under similar experimental conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 902-911 
    ISSN: 0006-3592
    Schlagwort(e): product inhibition ; growth modeling ; glycerol fermentation ; 1,3-propanediol ; C. butyricum ; K. pneumoniae ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The inhibition potentials of products and substrate on the growth ofClostridium butyricum and Klebsiella pneumoniae in the glycerol fermentation are examined from experimental data and with a mathematicalmodel. Whereas the inhibition potential of externally added and self-produced 1,3-propanediol is essentially the same, butyric acid produced by the culture is more toxic than that externally added. The same seems to apply for acetic acid. The inhibitory effect of butyric acid is due tothe total concentration instead of its undissociated form. For acetic acid, it cannot be distinguished between the total concentration and the undissociated formThe inhibition effects of products and substrate in the glycerol fermentation are irrespective of the strains, and, therefore, the same growth model can be used. The maximum product concentrations tolerated (critical concentrations C*pi) are 0.35 g/Lfor undissociated acetic acid, 10.1 g/L for total butyric acid, 16.6 g/L for ethanol, 71.4 g/L for 1,3-propanediol, and 187.6 g/L for glycerol, which are applicable to C. butyricum and K. pneumoniae grown under a variety of conditions. For 55 steady-states, which were obtained from different types of continuous cultures over a pHrange of 5.3-8.5 and under both substrate limitation and substrate excess, the proposed growth model fits the experimental data with an average deviation of 17.0%. The deviation of model description from experimental values reduces of 11.4% if only the steady-states with excessive substrate are considered. © 1994 John Wiley & Sons, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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