The Experts below are selected from a list of 2889 Experts worldwide ranked by ideXlab platform
Axel Göttlein - One of the best experts on this subject based on the ideXlab platform.
-
Regeneration of Mature Norway Spruce Stands: Early Effects of Selective Cutting and Clear Cutting on Seepage Water Quality and Soil Fertility
2020Co-Authors: Wendelin Weis, Christian Huber, Axel Göttlein, J. Galloway, E. Cowling, J. W. Erisman, J. Wisniewski, C. JordanAbstract:* Corresponding author. E-mails: Wendelin Weis: weisw@forst.tu-muenchen.de; Christian Huber: huber@forst.tu-muenchen.de; Axel Gottlein: goettlein@forst.tu-muenchen.de © 2001 with author. The cutting of trees influences element turnover in the forest ecosystem. The reduction of plant uptake, as well as an increased mineralization and nitrification due to higher soil temperature and soil moisture, can lead to considerable losses of nutrients from the main rooting zone. This may result in a reduced soil fertility and a decrease in drinking Water quality due to high nitrate concentrations in the Seepage Water. In Bavaria (Germany) selective cutting is preferred to clear cutting when initiating the regeneration of Norway spruce stands with European beech. This paper summarizes the early effects of both forest management practices on soil fertility and Seepage Water quality for three different sites. Shown are the concentrations of nitrogen and base cations in the Seepage Water as well as the Water and ion fluxes during the first year after tree cut. Nutrient inputs decreased on thinned plots and even more at clear-cuts. Nitrate concentrations in the Seepage Water are hardly affected by moderate thinning; however, on clear-cuts, the nitrate concentration increases significantly, and base cations are lost from the upper mineral soil. This effect is less obvious at sites where a dense ground vegetation, which is able to take up excess nitrogen, exists.
-
Causes for the small scale variability of nitrate concentration in Seepage Water of an N saturated mature spruce stand
Annals of Forest Science, 2012Co-Authors: Michael Kohlpaintner, Christian Huber, Boris Matejek, Axel GöttleinAbstract:Context In N-saturated forests nitrate concentrations in Seepage Water (\( {\text{N}}{{\text{O}}_3}{^{ - }_{\text{Seepage}}} \)) regularly show high spatial variability even within homogeneous stands. Up to now the reasons of this variability are not fully understood.
-
Improving the precision of estimating nitrate (NO3−) concentration in Seepage Water of forests by prestratification with soil samples
European Journal of Forest Research, 2012Co-Authors: Michael Kohlpaintner, Christian Huber, Axel GöttleinAbstract:Nitrate (NO3−) concentrations in Seepage Water (\( {\text{SW}}_{{{\text{NO}}_{ 3} }} \)) of N saturated forests regularly show a high spatial variability. As Seepage Water sampling is expensive, most studies use small numbers of soil solution samplers. This implies high uncertainties of calculated concentration and flux data. At the N saturated Hoglwald site we investigated, whether a preselection of Seepage Water sampling places by a prior intensive soil sampling can improve the precision of the estimation of \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \). We implemented 121 suction cups and analyzed the soil, removed with the soil auger during installation at the sampling depth of 40 cm, for Water extractable NO3−. The NO3− content in soil (\( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \)) was calculated and \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) was measured. With this data set we tested the correlation between \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) and \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) and simulated a random selection of sampling places (RS) as well as a prestratified sampling based on \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) (PS). With bootstrap statistics different numbers of replications (n) were tested and the 95% confidence interval (95% CI) was used to compare RS with PS. Highly significant correlations between \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) and \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) were found (r = 0.99***). It was even possible to calculate \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) from \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \). Here best results where achieved when \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) was determined from field moist soil samples. With PS the accuracy of the mean value of \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) improved considerably. To achieve a 95% CI lower than ±10%, 250 suction cups would be needed for RS compared to n = 20 for PS. Even 6 months after implementation, precision of mean \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) was higher for suction cup places selected with the PS method. A detailed description is given, how these findings may be applied in studies and monitoring programs focusing on NO3− leaching in forest ecosystems.
-
Ion concentrations and fluxes of Seepage Water before and after clear cutting of Norway spruce stands at Ballyhooly, Ireland, and Hoglwald, Germany
Biogeochemistry, 2010Co-Authors: Christian Huber, Wendelin Weis, Axel Göttlein, Julian Aherne, Edward P. Farrell, Thomas CumminsAbstract:Ion concentrations and fluxes in Seepage Water (below the main rooting zone) were compared before and after clear cutting at two similar long-term experimental Norway spruce forest plots. While Ballyhooly (Ireland) was influenced by sea salt deposition, Hoglwald (Germany) received high nitrogen (N) deposition. These differences were reflected in Seepage Water concentrations with sodium (Na+) and chloride (Cl–) dominating at Ballyhooly and high nitrate (NO3 −) and aluminium concentrations at Hoglwald. Following clear cutting of the forest plots, NO3 − concentrations peaked (Ballyhooly: 2018 μmolc L−1, Hoglwald: 2595 μmolc L−1). Moreover, at Ballyhooly, NO3 − concentrations and fluxes were continuously elevated for ~1.5 years. At Hoglwald, the clear cut plot, which was replanted with spruce and beech saplings, exhibited periodically elevated NO3 − concentrations with two distinct peaks. However, low concentrations, compared to the control (uncut) plot, were also observed. Further, at Hoglwald a plot with a pre-existing dense natural regeneration of Norway spruce exhibited much lower NO3 − concentrations before and after clear cutting. Nonetheless, NO3 − concentrations following clear cut at both sites were elevated at least periodically above European drinking Water standards (50 mg L−1). An important prerequisite for NO3 − leaching is that forests are N saturated or at least not N-limited; consequently chronic elevated N deposition may lead to increased deterioration of Seepage Water quality across Europe following forest disturbances (harvesting, windthrow, insect attacks). Clear cutting at Ballyhooly was responsible for significant element loss, especially of potassium, N and calcium, while magnesium loss was compensated by high sea salt inputs. At Hoglwald the contamination of Seepage Water with NO3 − has been the main problem for more than 20 years at the mature stand. A pre-existing regeneration can help to reduce NO3 − and cation leaching after cutting.
-
Microbial nitrogen‐turnover processes within the soil profile of a nitrogen‐saturated spruce forest and their relation to the small‐scale pattern of Seepage‐Water nitrate
Journal of Plant Nutrition and Soil Science, 2010Co-Authors: Boris Matejek, Christian Huber, Michael Kohlpaintner, Rainer Gasche, Michael Dannenmann, Axel Göttlein, Hans PapenAbstract:Microbial N-turnover processes were investigated in three different forest soil layers [organic (O) layer, 0-10cm depth (M 1 ), 10-40cm depth (M 2 )] of a N-saturated spruce stand at the Hoglwald Forest (Bavaria, SW Germany). The aim of the study was to provide a detailed insight into soil-layer-specific microbial production and consumption of inorganic N within the main rooting zone. Furthermore, we intended to clarify the relevance of each investigated soil layer on the observed high spatial variation of Seepage-Water nitrate (NO 3 ) concentration at 40cm depth. The 15 N-pool dilution technique was applied for determination of gross and net N-turnover rates in the different soil layers. Moreover, soil pH, C: N ratio, pool sizes of soil ammonium (NH4 + 4 ) and NO 3 , as well as amounts of microbial biomass C (C mic ) and N (N mic ) were determined. The Olayer had the greatest microbial-biomass density along with the highest gross and net N-turnover rates. 55% of the net nitrification occurred in the O layer, 20% in M 1, and 25% in M 2 (i.e., a considerable amount of net NO - 3 production was located in the mineral soil). Spatial variability of N-turnover rates even increased with increasing soil depth due to higher spatial variation of microbial biomass and C and N contents in soil. NH + 4 and NO 3 concentrations in the organic layer as well as NO 3 concentrations in M 2 were significantly correlated with NO 3 concentrations in Seepage Water at 40 cm depth. However, no significant correlation between NO 3 concentrations in Seepage Water and any N-turnover process was found. We suggest that in contrast to in situ field measurements the dislocation of the soil samples from their natural environment may have altered the spatial variability of N-turnover rates.
Holger Weiss - One of the best experts on this subject based on the ideXlab platform.
-
Arsenic Speciation for Investigation of Its Environmental Fate — A Case Study
Environmental Science Research, 2020Co-Authors: Birgit Daus, Rainer Wennrich, Jürgen Mattusch, Holger WeissAbstract:A tailings pond for dumping the fine grained residues of the tin ore processing was object of this study. The aim was the investigation of arsenic mobilization from the tailings material into the Seepage Water and the immobilization process into a precipitate. Different speciation techniques were applied to follow the way of the arsenic in this system. The Seepage Water was sampled and the total concentrations of the main constitutions as well as the arsenic species were analyzed. The mobilization and immobilization process was described by these methods.
-
kinetics of the arsenite oxidation in Seepage Water from a tin mill tailings pond
Talanta, 2000Co-Authors: Birgit Daus, Jiirgen Mattusch, Albrecht Paschke, Rainer Wennrich, Holger WeissAbstract:Abstract The kinetic of the oxidation of trivalent arsenic was investigated in synthetic as well as in natural samples of a tin mill Seepage Water. The influence of ferric ions and solid MnO2 on the process was studied. To determine the time dependence of the concentrations of the arsenic species, a series of samples were taken sequentially and analysed by coupling of ionchromatographic separation and ICP-MS detection. To investigate the naturally occurring oxidation reaction, original Seepage Water samples were filtered and spiked with As(III) (1 mg l−1) and Fe(II) (10 mg l−1) and shaken providing intensive contact with the air. Additional synthetic samples buffered with carbonate were used in similar experiments to simplify the system. The reaction was incomplete in the presence of excess of iron for both types of samples. The oxidation of As(III) was complete within 8 h in the presence of MnO2 (10 mg), but there was a difference in oxidation rates between the natural and the synthetic samples. The results are discussed with respect to the redox potentials and equilibrium constants.
Reinhard Niessner - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of heavy-metal-containing Seepage Water colloids by flow FFF, ultrafiltration, ELISA and AAS
Mikrochimica Acta, 1998Co-Authors: Thorsten Klein, Reinhard NiessnerAbstract:Heavy-metal-containing humic colloids from Seepage Water samples of three different municipal waste disposal plants were characterized in terms of molecular weight, hydrodynamic radius and heavy metal content. The size distribution of the colloids was determined with ultrafiltration (UF) and flow field-flow fractionation (flow FFF). The humic colloids in the Seepage Water samples were characterized using an off-line coupling of flow FFF with an enzyme-linked immunosorbent assay (ELISA) for humic substances. The heavy metals in the different size fractions obtained by UF and flow FFF were determined using atomic absorption spectroscopy (AAS). The colloid size distributions obtained with UF showed a maximum of the distribution in the range 1–10 nm. Seepage Water samples with high colloid concentrations had a second maximum in the range 0.1–1 μm. The determination of colloid size with flow FFF gave different colloid size distributions for the three waste disposal Seepage Waters, whereas Water from the oldest disposal plant showed the smallest colloid size with a maximum at 0.9 nm and Water from the most recent plant showed the largest colloid size with a maximum at 1.3 nm. The determination of particle classes with regard to the chemical composition using a scanning electron microscope with energy dispersive X-ray fluorescence detector (SEM/EDX) showed that the particles can be divided into five classes: silicates, insoluble salts, iron(hydr)oxides, carbonates and organic colloids (humic colloids). Flow FFF/ELISA off-line coupling showed that the most frequently occurring colloids of the Seepage Waters were humic colloids and investigation of the UF-size-fractions with AAS showed that up to 77% of the total mass of a heavy metal element can be bound to particles, especially to humic colloids. Additionally, the distributions of the heavy metals Fe, Cu and Zn were investigated with flow FFF/AAS off-line coupling. These results also showed that a substantial amount of these heavy metals (up to 46%) was bound to humic colloids.
-
Purification of organic contaminants in Seepage Water of a landfill by UV/ozone technique
Environmental Monitoring and Hazardous Waste Site Remediation, 1995Co-Authors: Stefan Vollmuth, A. Wenzel, Reinhard NiessnerAbstract:Seepage Water of landfills, where toxic waste is deposited, has high concentrations of chlorinated phenols (CP), polychlorinated biphenyls (PCB), and polycyclic aromatic hydrocarbons (PAH). The concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are usually found at ppq-level. Typical purification methods based on physical techniques produce highly contaminated residues, which have to be removed by combustion or deposition in a landfill. An alternative way is to destruct these contaminants by biological and chemical treatment. The behavior of the trace contaminants during UV/ozone treatment is described. Results show no significant effect for PCB and PCDD/PCDF. The CP and PAH were mostly reduced by UV/ozone treatment to a degradation ratio greater than 90%. An influence of the pH value on the UV/ozone treatment of Seepage Water could not be detected. A further experiment showed the degradability of PCDD/PCDF in pure Water solution. To reach better results for the degradation of organic trace contaminants the Seepage Water first can be treated with biological methods. Thus the high TOC-concentration of 3 g/l is reduced to 50 - 70%. A combination of biological and oxidative techniques diminishes the treatment costs and better exploitation of the oxidants is reached. Because of high light absorbance of the Seepage Water between 200 nm and 300 nm we developed a falling-film- photo-reactor to ensure, that every volume of the solution is exposed to UV-radiation.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
-
Degradation of PCDD, PCDF, PAH, PCB and chlorinated phenols during the destruction-treatment of landfill Seepage Water in laboratory model reactor (UV, ozone, and UV/ozone)
Chemosphere, 1995Co-Authors: Stefan Vollmuth, Reinhard NiessnerAbstract:Abstract Seepage Water of toxic waste landfills is polluted with high concentrations of toxic organic compounds. The concentrations in the Seepage Water we applied for chlorinated phenols are between 2 μg/1 and 1 mg/l, for PCB between 800 pg/l and 250 ng/l, for PAH between 200 ng/l and 12 μg/l and for PCDD and PCDF between 20 pg/l and 1 ng/l. Usual purification methods produce highly contaminated residues, which have to be treated by pyrolysis or are deposited again at a landfill. A better way is to destruct these contaminants by UV/ozone treatment. The treatment of Seepage Water by UV-irradiation, ozone and UV/ozone is compared. Results show no significant effect during all treatments for PCB and PCDD/PCDF. The chlorinated phenols and PAH were mostly destroyed by UV/ozone treatment more than 90 %. The pH value has no influence on the UV/ozone treatment of Seepage Water.
-
Formation of Polychlorinated Dibenzo-p-dioxins and Polychlorinated Dibenzofurans during the Photolysis of Pentachlorophenol-Containing Water.
Environmental Science & Technology, 1994Co-Authors: Stefan Vollmuth, Achim. Zajc, Reinhard NiessnerAbstract:Purification of Seepage Water or wasteWater by UV irradiation for the destruction of organic impurities is an upcoming method for Water treatment. Seepage Water of refuse dumps contains, besides other organic compounds, high concentrations of pentachlorophenol (PCP) and tetrachlorophenols (TCP). During the UV irradiation of PCP-containing Water samples, the formation of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) is possible. The toxicity equivalence value (TEQ) of the PCDDs/PCDFs increased in an irradiated solution containing purified PCP about by a factor of 150. In samples of technical PCP and Seepage Water with high TEQ, we found a decrease of the TEQ value, for example, the TEQ of 1931.0 pg/L of PCDD in technical PCP is reduced to 99,0 pg/L
Christian Huber - One of the best experts on this subject based on the ideXlab platform.
-
Regeneration of Mature Norway Spruce Stands: Early Effects of Selective Cutting and Clear Cutting on Seepage Water Quality and Soil Fertility
2020Co-Authors: Wendelin Weis, Christian Huber, Axel Göttlein, J. Galloway, E. Cowling, J. W. Erisman, J. Wisniewski, C. JordanAbstract:* Corresponding author. E-mails: Wendelin Weis: weisw@forst.tu-muenchen.de; Christian Huber: huber@forst.tu-muenchen.de; Axel Gottlein: goettlein@forst.tu-muenchen.de © 2001 with author. The cutting of trees influences element turnover in the forest ecosystem. The reduction of plant uptake, as well as an increased mineralization and nitrification due to higher soil temperature and soil moisture, can lead to considerable losses of nutrients from the main rooting zone. This may result in a reduced soil fertility and a decrease in drinking Water quality due to high nitrate concentrations in the Seepage Water. In Bavaria (Germany) selective cutting is preferred to clear cutting when initiating the regeneration of Norway spruce stands with European beech. This paper summarizes the early effects of both forest management practices on soil fertility and Seepage Water quality for three different sites. Shown are the concentrations of nitrogen and base cations in the Seepage Water as well as the Water and ion fluxes during the first year after tree cut. Nutrient inputs decreased on thinned plots and even more at clear-cuts. Nitrate concentrations in the Seepage Water are hardly affected by moderate thinning; however, on clear-cuts, the nitrate concentration increases significantly, and base cations are lost from the upper mineral soil. This effect is less obvious at sites where a dense ground vegetation, which is able to take up excess nitrogen, exists.
-
Causes for the small scale variability of nitrate concentration in Seepage Water of an N saturated mature spruce stand
Annals of Forest Science, 2012Co-Authors: Michael Kohlpaintner, Christian Huber, Boris Matejek, Axel GöttleinAbstract:Context In N-saturated forests nitrate concentrations in Seepage Water (\( {\text{N}}{{\text{O}}_3}{^{ - }_{\text{Seepage}}} \)) regularly show high spatial variability even within homogeneous stands. Up to now the reasons of this variability are not fully understood.
-
Improving the precision of estimating nitrate (NO3−) concentration in Seepage Water of forests by prestratification with soil samples
European Journal of Forest Research, 2012Co-Authors: Michael Kohlpaintner, Christian Huber, Axel GöttleinAbstract:Nitrate (NO3−) concentrations in Seepage Water (\( {\text{SW}}_{{{\text{NO}}_{ 3} }} \)) of N saturated forests regularly show a high spatial variability. As Seepage Water sampling is expensive, most studies use small numbers of soil solution samplers. This implies high uncertainties of calculated concentration and flux data. At the N saturated Hoglwald site we investigated, whether a preselection of Seepage Water sampling places by a prior intensive soil sampling can improve the precision of the estimation of \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \). We implemented 121 suction cups and analyzed the soil, removed with the soil auger during installation at the sampling depth of 40 cm, for Water extractable NO3−. The NO3− content in soil (\( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \)) was calculated and \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) was measured. With this data set we tested the correlation between \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) and \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) and simulated a random selection of sampling places (RS) as well as a prestratified sampling based on \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) (PS). With bootstrap statistics different numbers of replications (n) were tested and the 95% confidence interval (95% CI) was used to compare RS with PS. Highly significant correlations between \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) and \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) were found (r = 0.99***). It was even possible to calculate \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) from \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \). Here best results where achieved when \( {\text{Soil}}_{{{\text{NO}}_{ 3} }} \) was determined from field moist soil samples. With PS the accuracy of the mean value of \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) improved considerably. To achieve a 95% CI lower than ±10%, 250 suction cups would be needed for RS compared to n = 20 for PS. Even 6 months after implementation, precision of mean \( {\text{SW}}_{{{\text{NO}}_{ 3} }} \) was higher for suction cup places selected with the PS method. A detailed description is given, how these findings may be applied in studies and monitoring programs focusing on NO3− leaching in forest ecosystems.
-
Ion concentrations and fluxes of Seepage Water before and after clear cutting of Norway spruce stands at Ballyhooly, Ireland, and Hoglwald, Germany
Biogeochemistry, 2010Co-Authors: Christian Huber, Wendelin Weis, Axel Göttlein, Julian Aherne, Edward P. Farrell, Thomas CumminsAbstract:Ion concentrations and fluxes in Seepage Water (below the main rooting zone) were compared before and after clear cutting at two similar long-term experimental Norway spruce forest plots. While Ballyhooly (Ireland) was influenced by sea salt deposition, Hoglwald (Germany) received high nitrogen (N) deposition. These differences were reflected in Seepage Water concentrations with sodium (Na+) and chloride (Cl–) dominating at Ballyhooly and high nitrate (NO3 −) and aluminium concentrations at Hoglwald. Following clear cutting of the forest plots, NO3 − concentrations peaked (Ballyhooly: 2018 μmolc L−1, Hoglwald: 2595 μmolc L−1). Moreover, at Ballyhooly, NO3 − concentrations and fluxes were continuously elevated for ~1.5 years. At Hoglwald, the clear cut plot, which was replanted with spruce and beech saplings, exhibited periodically elevated NO3 − concentrations with two distinct peaks. However, low concentrations, compared to the control (uncut) plot, were also observed. Further, at Hoglwald a plot with a pre-existing dense natural regeneration of Norway spruce exhibited much lower NO3 − concentrations before and after clear cutting. Nonetheless, NO3 − concentrations following clear cut at both sites were elevated at least periodically above European drinking Water standards (50 mg L−1). An important prerequisite for NO3 − leaching is that forests are N saturated or at least not N-limited; consequently chronic elevated N deposition may lead to increased deterioration of Seepage Water quality across Europe following forest disturbances (harvesting, windthrow, insect attacks). Clear cutting at Ballyhooly was responsible for significant element loss, especially of potassium, N and calcium, while magnesium loss was compensated by high sea salt inputs. At Hoglwald the contamination of Seepage Water with NO3 − has been the main problem for more than 20 years at the mature stand. A pre-existing regeneration can help to reduce NO3 − and cation leaching after cutting.
-
Microbial nitrogen‐turnover processes within the soil profile of a nitrogen‐saturated spruce forest and their relation to the small‐scale pattern of Seepage‐Water nitrate
Journal of Plant Nutrition and Soil Science, 2010Co-Authors: Boris Matejek, Christian Huber, Michael Kohlpaintner, Rainer Gasche, Michael Dannenmann, Axel Göttlein, Hans PapenAbstract:Microbial N-turnover processes were investigated in three different forest soil layers [organic (O) layer, 0-10cm depth (M 1 ), 10-40cm depth (M 2 )] of a N-saturated spruce stand at the Hoglwald Forest (Bavaria, SW Germany). The aim of the study was to provide a detailed insight into soil-layer-specific microbial production and consumption of inorganic N within the main rooting zone. Furthermore, we intended to clarify the relevance of each investigated soil layer on the observed high spatial variation of Seepage-Water nitrate (NO 3 ) concentration at 40cm depth. The 15 N-pool dilution technique was applied for determination of gross and net N-turnover rates in the different soil layers. Moreover, soil pH, C: N ratio, pool sizes of soil ammonium (NH4 + 4 ) and NO 3 , as well as amounts of microbial biomass C (C mic ) and N (N mic ) were determined. The Olayer had the greatest microbial-biomass density along with the highest gross and net N-turnover rates. 55% of the net nitrification occurred in the O layer, 20% in M 1, and 25% in M 2 (i.e., a considerable amount of net NO - 3 production was located in the mineral soil). Spatial variability of N-turnover rates even increased with increasing soil depth due to higher spatial variation of microbial biomass and C and N contents in soil. NH + 4 and NO 3 concentrations in the organic layer as well as NO 3 concentrations in M 2 were significantly correlated with NO 3 concentrations in Seepage Water at 40 cm depth. However, no significant correlation between NO 3 concentrations in Seepage Water and any N-turnover process was found. We suggest that in contrast to in situ field measurements the dislocation of the soil samples from their natural environment may have altered the spatial variability of N-turnover rates.
Birgit Daus - One of the best experts on this subject based on the ideXlab platform.
-
Arsenic Speciation for Investigation of Its Environmental Fate — A Case Study
Environmental Science Research, 2020Co-Authors: Birgit Daus, Rainer Wennrich, Jürgen Mattusch, Holger WeissAbstract:A tailings pond for dumping the fine grained residues of the tin ore processing was object of this study. The aim was the investigation of arsenic mobilization from the tailings material into the Seepage Water and the immobilization process into a precipitate. Different speciation techniques were applied to follow the way of the arsenic in this system. The Seepage Water was sampled and the total concentrations of the main constitutions as well as the arsenic species were analyzed. The mobilization and immobilization process was described by these methods.
-
kinetics of the arsenite oxidation in Seepage Water from a tin mill tailings pond
Talanta, 2000Co-Authors: Birgit Daus, Jiirgen Mattusch, Albrecht Paschke, Rainer Wennrich, Holger WeissAbstract:Abstract The kinetic of the oxidation of trivalent arsenic was investigated in synthetic as well as in natural samples of a tin mill Seepage Water. The influence of ferric ions and solid MnO2 on the process was studied. To determine the time dependence of the concentrations of the arsenic species, a series of samples were taken sequentially and analysed by coupling of ionchromatographic separation and ICP-MS detection. To investigate the naturally occurring oxidation reaction, original Seepage Water samples were filtered and spiked with As(III) (1 mg l−1) and Fe(II) (10 mg l−1) and shaken providing intensive contact with the air. Additional synthetic samples buffered with carbonate were used in similar experiments to simplify the system. The reaction was incomplete in the presence of excess of iron for both types of samples. The oxidation of As(III) was complete within 8 h in the presence of MnO2 (10 mg), but there was a difference in oxidation rates between the natural and the synthetic samples. The results are discussed with respect to the redox potentials and equilibrium constants.