Refine search
Results 1-10 of 99
The carbon budget of Canadian forests: A sensitivity analysis of changes in disturbance regimes, growth rates, and decomposition rates.
1994
Kurz W.A. | Apps M.J.
Changes in chemistry and mineralogy of forest soils by acid rain.
1992
Rampazzo N. | Blum W.E.H.
Simulation of the long-term soil response to acid deposition in various buffer ranges.
1989
Vries W. de | Posch M. | Kaemaeri J.
Use of a chemical equilibrium model to understand soil chemical processes that influence soil solution and surface water alkalinity.
1988
David M.B. | Reuss J.O. | Walthall P.M.
Assessment of the interactions of metals and nitrilotriacetic acid in soil/sludge mixtures.
1987
Garnett K. | Kirk P.W.W. | Lester J.N. | Perry R.
Comparative kinetic desorption of 60Co, 85Sr and 134Cs from a contaminated natural silica sand column: Influence of varying physicochemical conditions and dissolved organic matter
2006
Solovitch-Vella, N. | Garnier, J.-M. | Laboratoire d'Etudes Radioécologiques des milieux Continental et marin (IRSN/PRP-ENV/SESURE/LERCM) ; Service d'étude et de surveillance de la radioactivité dans l'environnement (PRP-ENV/SESURE) ; Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN) | Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE) ; Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
In order to determine the mechanisms of the retention of 60Co, 85Sr and 134Cs in natural silica sand columns, desorption experiments were performed by changes of pH and ionic strength and by injection of natural organic matter (NOM). Injection of KCl (0.1 M) resulted in a high release of 60Co (60-100%) and 85Sr (72-100%) but a smaller release of 134Cs (31-66%). Only limited release of 60Co (66%) and 85Sr (71%) and no release of 134Cs were observed by injection of NOM. The different percentages of desorption were related to the chemical characteristics of the organic colloids previously retained in columns before the desorption step. The results evidenced different sorption processes on energetically heterogeneous surface sites. According to the initial conditions, the binding of the radionuclides to the solid phase resulted from weak and easily reversible sorption processes to strong association probably by inner sphere complexes. The rather weak release of 134Cs by KCl was attributed to the strong retention of 134Cs by clay coatings on the natural silica sand surfaces. © 2005 Elsevier Ltd. All rights reserved.
Show more [+] Less [-]Soil acidification in Swiss forest ecosystems
2002
Braun, S. (Institute for Applied Plant Biology, Schonenbuch, (Switzerland)) | Kurz, D. | Fluckiger, W.
Soil water measurements in Swiss forest plots show a decrease of the ratio between base cations and aluminium within last 4 years. The decrease is significant in at least one soil layer in 12 of 14 plots and is strongest in areas with high acid deposition. In some of the soils the critical ratio of 1 is being reached today. The development is compared with model estimates. In Switzerland, 80% of acid deposition is made up by nitrogen compounds
Show more [+] Less [-]National baseline survey of soil quality in the Netherlands
2009
Brus, D.J. | Lamé, F.P.J. | Nieuwenhuis, R.H.
To determine background values of the 252 chemical compounds listed in Dutch legislation, a survey was designed with the aim of estimating percentiles of the cumulative frequency distributions and areal fractions exceeding the former, legislative reference values. Sampling locations were selected by probability sampling, so that in estimating the target quantities no model assumptions on the spatial variation were required, and valid estimates could be obtained by design-based inference. Strata in random sampling were formed by overlaying an aggregated soil map and land use map. For most of the heavy metals the areal fraction with concentrations in the topsoil (0-10 cm) exceeding the reference value was smaller than the allowable maximum of 5%. For these compounds a background value was determined smaller than the reference value. Exceptions were V, Co, Ba and Cu, for which a background value was defined (slightly) larger than the reference value. Legislative background values can be best derived by probability sampling and design-based estimation.
Show more [+] Less [-]Vertical distribution of organochlorine pesticides in humus along Alpine altitudinal profiles in relation to ambiental parameters
2009
Kirchner, M. | Faus-Kessler, T. | Jakobi, G. | Levy, W. | Henkelmann, B. | Bernhöft, S. | Kotalik, J. | Zsolnay, A. | Bassan, R. | Belis, C. | Kräuchi, N. | Moche, W. | Simončič, P. | Uhl, M. | Weiss, P. | Schramm, K.W.
In forest soils along vertical profiles located in different parts of the Alps, concentrations of persistent organic pollutants (POPs), namely organochlorine pesticides (OCPs) like dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCH), heptachlor, aldrin, dieldrin and mirex, were measured. Though local characteristics of the sites are influenced by numerous factors like orographic and meteorological parameters, forest stand characteristics and humus parameters, we ascertained a marked vertical increase of concentrations of some organochlorine compounds in the soil. On the basis of climatological values of each site, we found that the contamination increase with altitude can be ascribed to a certain ‘cold condensation effect’. In addition, the perennial atmospheric deposition of POPs is controlled by precipitation. Other key parameters explaining the accumulation of POPs are the soil organic carbon stocks, the turnover times, the re-volatilisation and degradation processes, which vary with altitude. Caused by temperature-dependent processes regarding deposition, re-volatilization and decomposition of POPs, the concentration of organochlorine pesticides varies in the Alpine region with altitude.
Show more [+] Less [-]Simultaneous removal of arsenic and toxic metals from contaminated soil: Laboratory development and pilot scale demonstration
2022
Morales Arteaga, Juan Francisco | Gluhar, Simon | Kaurin, Anela | Lestan, Domen
Soil chemistry of toxic metalloids and metals differs, making their simultaneous removal difficult. Soil contaminated with As, Pb, Zn and Cd was washed with oxalic acid, Na-dithionite and EDTA solution. Toxic elements were removed from the washing solution by alkalinisation with CaO to a pH 12.5: As was co-precipitated with Fe from Fe-EDTA chelate formed after the soil washing. The toxic metals precipitated after substitution of their EDTA chelates with Ca. The novel method was scaled up on the ReSoil® platform. On average, 60, 76, 29, and 53% of As, Pb, Zn, and Cd were removed, no wastewater was generated and EDTA was recycled. Addition of zero-valent iron reduced the toxic elements’ leachability. Remediation was most effective for As: phytoaccessibility (CaCl₂ extraction), mobility (NH₄NO₃), and accessibility from human gastric and gastrointestinal phases were reduced 22, 104, 6, and 51 times, respectively. Remediation increased pH but had no effect on soil functioning assessed by fluorescein diacetate hydrolysis, dehydrogenase, β-glucosidase, urease, acid and alkaline phosphatase activities. Brassica napus produced 1.9 times more biomass on remediated soil, accumulated no As and 5.0, 2.6, and 9.0 times less Pb, Zn and Cd, respectively. We demonstrated the novel remediation technology as cost-efficient (material cost = 41.86 € t⁻¹) and sustainable.
Show more [+] Less [-]