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PLATIN (plant-atmosphere interaction) I: a model of plant-atmosphere interaction for estimating absorbed doses of gaseous air pollutants
1997
Grunhage, L. | Haenel, H.D. (Institute for Plant Ecology, University of Giessen, Heinrich-Buff-Ring 38, D-35392 Giessen, Germany)
Critical levels for ozone effects on vegetation in Europe
1997
Fuhrer, J. | Skarby, L. | Ashmore, M.R. (Swiss Federal Research Station for Agroecology and Agriculture (FAL), Institute of Environmental Protection and Agriculture (IUL) Liebefeld, CH-3003 Bern (Switzerland))
Response of six European forest sites to decided and proposed air pollutant emission reductions
1997
Walse, C. | Schopp, W. | Warfvinge, P. (Deptartment of Chemical Engineering II, Lund University, PO Box 124, 221 00 Lund (Sweden))
Measured and predicted volatilisation fluxes of PCBS from contaminated sludge-amended soils
1997
Cousins, I.T. | Hartlieb, N. | Teichmann, C. | Jones, K.C. (Environmental Science Division, Institute of Environmental and Biological Sciences, Lancaster University, Lancaster LA1 4YQ (United Kingdom))
Congener specific transfer of PCDD/Fs from air to cows' milk: an evaluation of current modelling approaches
1997
Douben, P.E.T. | Alcock, R.E. | Jones, K.C. (Her Majesty's Inspectorate of Pollution, 2 Marsham Street, London SW1P 3EB (United Kingdom))
Uptake from water, release and tissue distribution of sup(54)Mn in the rainbow trout (Oncorhynchus mykiss Walbaum)
1997
Adam, C. | Garnier-Laplace, J. | Baudin, J.P. (Institut de Protection et de Surete Nucleaire, Departement de Protection de l'Environnement, Laboratoire de Radioecologie Experimentale, 13108 Saint-Paul-Lez-Durance Cedex (France))
Effects of ozone on vegetation
1997
Bastrup-Birk, A. | Mortensen, L.
Modelling leaching of inorganic Hg(II) in a Scandinavian iron-humus podzol — validation and long-term leaching under various deposition rates
1997
Schlüter, K. | Gäth, S.
Increasing mercury contents are reported from freshwater systems and fish in northern Europe and North America. Mercury input from soils is a major source with the leaching being affected by increased atmospheric mercury deposition compared to pre-industrial times and by other environmental conditions such as acid rain. The results of a mathematical model-calculation of vertical inorganic Hg(II) leaching in a Scandinavian iron-humus podzol under different atmospheric input rates of mercury are presented. Leaching under background rain conditions was calculated to be considerably stronger than under acid rain conditions. Increasing fractions of deposited soluble or solute atmospheric mercury were leached from the Of₍ₕ₎-horizon with decreasing soil content of soluble mercury under acid rain conditions; this effect was less pronounced under background rain conditions. The steady state concentrations of soluble mercury of the upper soil horizons were calculated and compared with the actual concentrations of total (= soluble + insoluble mercury) and extractable (= estimate of soluble) mercury measured in these horizons. The results indicate that even if the deposition of airborne mercury to soil is strongly reduced, the total mercury content of the soil decreases only slowly. It may take decades or even centuries before a new steady state concentration of total mercury is established in the soil. The decrease of the mercury concentration in the Of₍ₕ₎-horizon is probably largely dependent on the turnover of organic matter, binding most of the deposited airborne mercury in an insoluble form. Hence, present day mercury leaching is likely to be dominated by mercury deposited during former times and temporarily retained in an insoluble form in the organic matter.
Show more [+] Less [-]Possibilities for increased carbon sequestration through the implementation of rational forest management in Russia
1997
Shvidenko, Anatoly | Nilsson, Sten | Roshkov, Vjacheslav
Huge areas of the Russian forests suffer from insufficient forest management. A scenario has been developed for an improved management program that would be implemented over the next 40 years. Possible options have been aggregated into three interlinked groups: increase in forest productivity through improvement of the forest conditions and the structure of the Forest Fund, decrease of carbon release by mitigation of disturbance regimes, and improvement of landscape management. One prerequisite in developing this scenario was that the cost of sequestering one ton of carbon should not exceed US$3 (1992 dollar value). In this article a simple model is described to illustrate the following possibilities for increased carbon fixation by improved forest management: large-scale reforestation and afforestation, replacement of stands with low productivity and replacement of so called soft deciduous species and “climax” stands, and implementation of rational silviculture (thinning). The results indicate a potential for an increase in carbon fixation in Russian forest ecosystems of 24.4 Pg over 100 years, after the first year that the actions discussed are implemented. The net sink of carbon was determined to be 16.5 Pg in the “low” estimate and 42.5 Pg in the “high” estimate. There are, however, many uncertainties in the data and there are difficulties in adequately modeling the possibilities for implementation under current conditions in Russia. In spite of these uncertainties, we conclude that there is great potential for economically justified increased carbon fixation through improved forest management in Russia.
Show more [+] Less [-]The internal barriers of rotation for the 209 polychlorinated biphenyls
1997
Andersson, Patrik L. | Haglund, Peter | Tysklind, Mats
The internal barrier of rotation (Erot) was calculated for all 209 polychlorinated biphenyls (PCBs) by using a semi-empirical method, viz. the Austin Model 1 (AMI) Hamiltonian. The difference in total energy between a forced planar state and an optimised twisted structure was defined as Erot. The Erot values were in the range of 8.33 to 483 kj/mol, and were significantly influenced by the number of chlorine atoms inortho position. An additional structural characteristic of the PCBs influencing Erot ofortho substituted congeners was substitution by chlorine atoms in vicinalmeta positions, which is assumed to prevent outward bending ofortho substituents. This so-called buttressing effect contributed with 4 to 31 kj/mol per added chlorine atom. In conclusion, the internal barrier of rotation, calculated for all 209 PCBs, provides an important structure dependent physico-chemical parameter for multivariate modelling of future quantitative structure-activity and structure-property relationships (QSARs/QSPRs).
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