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431.
von Bobrutzki K Ammon C Berg W Einert P Fiedler M Müller HJ Scherer D Strohbach B 《Environmental monitoring and assessment》2012,184(6):3775-3787
Agricultural NH3 emissions affect air quality and influence the nitrogen cycle. In the subject study, NH3 emissions from a broiler farm and the resulting atmospheric concentrations in the immediate vicinity during three growing
cycles have been quantified. Additionally, vegetation along a transect in an adjacent woodland was analysed. The emissions
were as high as 10 kg NH3 h−1 and the atmospheric concentrations ranged between 33 and 124 μg NH3 m−3 per week in the immediate vicinity. Measurements of the atmospheric concentrations over 7 weeks showed a substantial decline
of mean concentrations (based on a 3-week average) from ∼13 to <3 μg NH3 m−3, at 45- and 415-m distance from the farm. Vegetation surveys showed that nitrophilous species flourished when they grew closest
to the farm (their occurrence sank proportionately with distance). A clearly visible damage of pine trees was observed within
200 m of the farm; this illustrated the significant impact of NH3 emissions from agricultural sources on the sensitive ecosystem. 相似文献
432.
Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in human liver and adipose tissue samples from Belgium 总被引:3,自引:0,他引:3
Levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in paired human adipose tissue and liver samples (n=25) from Belgium. Average concentrations and standard deviation of sum PBDEs (congeners 28, 47, 99, 100, 153, 154 and 183) were 5.3+/-3.0 (range 1.4-13.2) and 3.6+/-2.1 (range 1.0-10.0)ngg(-1) lipid weight (lw) in adipose tissue and liver, respectively. These concentrations were similar to reported PBDE data from Belgium and were at the lower end of the concentration range reported elsewhere in the world. In both tissues under study, BDE 153 and BDE 47 were the most abundant PBDE congeners, contributing approximately 35% and 25% to the total PBDE content. Average concentrations and range of PCBs (sum of 23 congeners) were 490 (range 70-1130) and 380 (range 90-1140)ngg(-1)lw in adipose tissue and liver, respectively. No correlation between age and concentrations of PBDEs could be found (r=0.04), while PCB concentrations correlated significantly with age (r=0.62, p<0.01, for the sum PCBs; r=0.64, p<0.01 for PCB 153 alone). Factors, such as exposure pathways (food, dust and air), rates of bioaccumulation, metabolism and elimination, influence the concentrations of PBDEs differently than those of PCBs in humans. 相似文献
433.
David Werner Hrissi K. Karapanagioti Patrick Hhener 《Journal of contaminant hydrology》2009,108(1-2):54-63
A partitioning tracer test based on gas-phase diffusion in the vadose zone yields estimates of the residual nonaqueous phase liquid (NAPL) saturation. The present paper investigates this technique further by studying diffusive tracer breakthrough curves in the vadose zone for a heterogeneous NAPL distribution. Tracer experiments were performed in a lysimeter with a horizontal layer of artificial kerosene embedded in unsaturated sand. Tracer disappearance curves at the injection point and tracer breakthrough curves at some distance from the injection point were measured inside and outside of the NAPL layer. A numerical code was used to generate independent model predictions based on the physicochemical sand, NAPL, and tracer properties. The measured and modeled tracer breakthrough curves were in good agreement confirming the validity of important modeling assumptions such as negligible sorption of chlorofluorocarbon (CFC) tracers to the uncontaminated sand and their fast reversible partitioning between the soil air and the NAPL phase. Subsequently, the model was used to investigate different configurations of NAPL contamination. The experimental and model results show that the tracer disappearance curves of a single-well diffusive partitioning tracer test (DPTT) are dominated by the near-field presence of NAPL around the tip of the soil gas probe. In contrast, breakthrough curves of inter-well tracer tests reflect the NAPL saturation in between the probes, although there is no unique interpretation of the tracer signals if the NAPL distribution is heterogeneous. Numerical modeling is useful for the planning of a DPTT application. Simulations suggest that several cubic meters of soil can be investigated with a single inter-well partitioning tracer test of 24-hour duration by placing the injection point in the center of the investigated soil volume and probes at up to 1 m distance for the monitoring of gaseous tracers. 相似文献
434.
K. Butterbach-Bahl M. Kahl L. Mykhayliv C. Werner R. Kiese C. Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(7):1392-1402
Soils are a significant source for atmospheric NO. However, due to the limited number of measurements and in view of the high temporal and spatial variability of NO emissions, as originating from dependencies from a series of environmental constraints such as soil properties, meteorology or N fertilization, inventories of soil NO emissions are still highly uncertain. In this work, the agricultural DNDC model was modified and applied on site scale in order to evaluate its capability to simulate soil NO emissions. DNDC captured differences in the magnitude of NO emissions between sites, but was less successful when simulating observed day-by-day variations. However, major peak emission events, e.g. due to fertilizer application or following rainfall events, were mostly simulated. DNDC as well as its forest version Forest-DNDC were finally linked to a GIS to calculate NO emissions from agricultural and forest soils across Europe. Using the same databases for agricultural soils, we also compared our estimate with other commonly used methodologies (Skiba-EMEP/CORINAIR, Yienger and Levy, Stehfest and Bouwman). A canopy reduction factor was not applied in this study. Estimates for NO emissions for agricultural soils for EU15 states varied in a range of 48.9–189.8 kt NO-N for the year 2000 depending on the approach used (Yienger and Levy > DNDC > Stehfest and Bouwman > Skiba-EMEP/CORINAIR). For forests, using the model Forest-DNDC as the only approach, we calculated soil NO emissions to be 75.1 kt NO-N yr?1. The results show that soils in EU15 states are significant sources of atmospheric NO, though the share of soil NO emissions on total NOx emissions (incl. NOx emissions by combustion processes) in EU15 was only 4–6%. Given that soil NO emissions are largely driven by the availability of inorganic nitrogen (fertilization) and temperature, emissions are larger during the vegetation period. Especially during early summer when fertilizer-induced NO emissions from agricultural soils are peaking, the contribution of soil emissions to total NOx emissions may most likely be well above 10%. 相似文献
435.
Kevin E. Percy Sirkku Manninen Karl-Heinz Häberle H. Werner Rainer Matyssek 《Environmental pollution (Barking, Essex : 1987)》2009,157(5):1657-1665
We examined the effect of ozone (O3) on Norway spruce (Picea abies) needle epicuticular wax over three seasons at the Kranzberg Ozone Fumigation Experiment. Exposure to 2× ambient O3 ranged from 64.5 to 74.2 μl O3 l−1 h AOT40, and 117.1 to 123.2 nl O3 l−1 4th highest daily maximum 8-h average O3 concentration. The proportion of current-year needle surface covered by wax tubes, tube aggregates, and plates decreased (P = 0.011) under 2× O3. Epistomatal chambers had increased deposits of amorphous wax. Proportion of secondary alcohols varied due to year (P = 0.004) and O3 treatment (P = 0.029). Secondary alcohols were reduced by 9.1% under 2× O3. Exposure to 2× O3 increased (P = 0.037) proportions of fatty acids by 29%. Opposing trends in secondary alcohols and fatty acids indicate a direct action of O3 on wax biosynthesis. These results demonstrate O3-induced changes in biologically important needle surface characteristics of 50-year-old field-grown trees. 相似文献
436.
Effect of biochar on the fate of volatile petroleum hydrocarbons in an aerobic sandy soil 总被引:2,自引:0,他引:2
Biochar addition to soil is currently being investigated as a novel technology to remediate polluted sites. A critical consideration is the impact of biochar on the intrinsic microbial pollutant degradation, in particular at sites polluted with a mixture of readily biodegradable and more persistent organic pollutants. We therefore studied the impact of biochar (2% on dry weight basis) on the fate of volatile petroleum hydrocarbons in an aerobic sandy soil with batch and column studies. The soil-water partitioning coefficient, K(d), was enhanced in the biochar-amended soil up to a factor 36, and petroleum hydrocarbon vapor migration was retarded accordingly. Despite increased sorption, in particular of monoaromatic hydrocarbons, the overall microbial respiration was comparable in the biochar-amended and unamended soil. This was due to more rapid biodegradation of linear, cyclic and branched alkanes in the biochar amended soil. We concluded that the total petroleum hydrocarbon degradation rate was controlled by a factor other than substrate availability and the reduced availability of monoaromatic hydrocarbons in the biochar amended soil led to greater biodegradation of the other petroleum compounds. 相似文献
437.
Biomineralization dependent on bacterial activity has been described for struvite which is formed in soils, guano, putrescent matter and sediments. A new biomineral containing nickel instead of magnesium, Ni(NH4)(PO4) . 6H2O, has been identified. It was formed by nickel resistant Streptomyces acidiscabies E13, and putatively named nickel struvite. The mineral formation is dependent on biological activity since non-viable bacterial cells are not capable to induce formation of Ni-struvite under identical conditions. Formation of Ni-struvite was observed on colony surfaces upon prolonged incubation of solid minimal or complex media containing elevated concentrations of 8-15mM NiCl2. The formation of magnesium containing crystals was not observed although Mg2+ is present in the medium. However, the process was not depending on desiccation since small crystals attached to the mycelial biomass of the bacteria were observed microscopically also in liquid cultures of nickel supplemented minimal and complex media after two weeks of incubation. The capacity to induce biomineralization of a nickel containing mineral is postulated to constitute a resistance factor, allowing the soil bacterium to withstand high nickel concentrations. The strain shows nickel resistance as an adaption to its habitat, since this bacterium was isolated from a former uranium mining site in Eastern Thuringia, Germany, where nickel concentrations of up to 2000ppm (translating to appr. 30mM) occur as a result of former mining activities. 相似文献
438.
Maren Kruse-Plass Frieder Hofmann Ulrike Kuhn Mathias Otto Ulrich Schlechtriemen Boris Schröder Rudolf Vögel Werner Wosniok 《Environmental Sciences Europe》2017,29(1):12
In this commentary, we respond to a report of the EFSA GMO Panel (EFSA EFSA Supp Publ, 1) that criticises the outcomes of two studies published in this journal (Hofmann et al. Environ Sci Eur 26: 24, 2; Environ Sci Eur 28: 14, 3). Both publications relate to the environmental risk assessment and management of Bt-maize, including maize events MON810, Bt11 and maize 1507. The results of Hofmann et al. (Environ Sci Eur 26: 24, 2), using standardised pollen mass filter deposition measurements, indicated that the EFSA Panel model had underestimated pollen deposition and, hence, exposure of non-target organisms to Bt-maize pollen. The results implied a need for safety buffer distances in the kilometre range for protected nature reserve areas instead of the 20–30 m range recommended by the EFSA Panel. As a result, the EFSA Panel revised their model (EFSA EFSA J 13: 4127, 4), adopting the slope of the empirical data from Hofmann et al. The intercept, however, was substantially reduced to less than 1% at one point by introducing further assumptions based on the estimates of mainly panel members, citing possible ‘uncertainty’. Hofmann et al. (Environ Sci Eur 28: 14, 3) published extensive empirical data regarding pollen deposition on leaves. These results were part of a larger 3-year study involving detailed measurements of pollen release, dispersal and deposition over the maize flowering period. The data collected in situ confirmed the previous predictions of Hofmann et al. (Environ Sci Eur 26: 24, 2). Mean levels and observed variability of pollen deposition on maize and four lepidopteran host plants exceeded the assumptions and disagreed with the conclusions of the EFSA Panel. The EFSA Panel reacted in a report (EFSA EFSA Supp Publ, 1) criticising the methods and outcomes of the two published studies of Hofmann et al. while reaffirming their original recommendations. We respond here point-by-point, showing that the critique is not justified. Based on our results on Urtica leaf pollen density, we confirm the need for specific environmental impact assessments for Bt-maize cultivation with respect to protected habitats within isolation buffer distances in the kilometre range. 相似文献
439.
440.
Modeling the Effects of Tile Drain Placement on the Hydrologic Function of Farmed Prairie Wetlands
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Brett Werner John Tracy W. Carter Johnson Richard A. Voldseth Glenn R. Guntenspergen Bruce Millett 《Journal of the American Water Resources Association》2016,52(6):1482-1492
The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well‐published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in agricultural areas of South Dakota in North America, wetland hydroperiod was found to be more sensitive to the depth that drain tile is installed relative to the bottom of the wetland basin than to distance‐based setbacks. Because tile drainage can change the hydrologic conditions of wetlands, even when deployed in upland catchments, tile drainage plans should be evaluated more closely for the potential impacts they might have on the ecological services that these wetlands currently provide. Future research should investigate further how drainage impacts are affected by climate variability and change. 相似文献