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Behaviour of arsenic in forested catchments following a high-pollution period
2011
Novák, Martin | Erbanova, Lucie | Fottova, Daniela | Cudlin, P. (Pavel) | Kubena, Ales
Due to high availability of adsorption sites, forested catchments could be net sinks for pollutant arsenic both during the period of increasing and decreasing pollution. We tested this hypothesis along a north–south pollution gradient in spruce die-back affected areas of Central Europe. For two water years (2007–2008), we monitored As fluxes via spruce-canopy throughfall, open-area precipitation, and runoff in four headwater catchments (Czech Republic). Since 1980, atmospheric As inputs decreased 26 times in the north, and 13 times in the south. Arsenic export by runoff was similar to atmospheric inputs at three sites, resulting in a near-zero As mass balance. One site exhibited a net export of As (2.2 g ha⁻¹ yr⁻¹). In contrast, the preceding period (1995–2006) showed much higher As fluxes, and higher As export. Czech catchments do not serve as net sinks of atmospheric As. A considerable proportion of old industrial arsenic is flushed out of the soil.
Show more [+] Less [-]Transport of polycyclic aromatic hydrocarbons in highly vulnerable karst systems
2011
Schwarz, Kerstin | Gocht, Tilman | Grathwohl, Peter
Fluxes of polycyclic aromatic hydrocarbons (PAHs) were investigated along the route of transport in a south German karst system. Atmospheric deposition, seepage water in caves and spring water at the outlet of the catchment were monitored continuously over 1.5 years allowing the establishment of an input/output mass balance at the catchment scale. The results reveal that, even in the highly vulnerable karst catchment, PAHs are effectively retained in the soils. Only during high discharge events, such as snowmelt in spring, increasing PAH concentrations at the outlet of the catchment indicates a mobilization of the pollutants. These events are typically correlated with increasing particle concentrations. Based on our results, we conclude that particle-facilitated transport is the dominating cause of PAH mobilization. In summary, PAHs accumulate over time in soils and only occasionally high discharge events cause a short concentration pulse to be flushed through the karst system.
Show more [+] Less [-]Determination of PM₁₀ deposition based on antimony flux to selected urban surfaces
2011
Langner, Marcel | Kull, Martin | Endlicher, Wilfried R.
Deposition of PM₁₀ particles to several types of urban surfaces was investigated within this study. Antimony was chosen as a tracer element to calculate dry deposition velocities for PM₁₀, since antimony proved to be present almost exclusively in PM₁₀ particles in ambient urban air. During 18 months, eight sampling sites in Berlin and Karlsruhe, two cities in Germany, were operated. PM₁₀ concentrations and dry deposition were routinely sampled as two week averages. Additionally, leaf-samples were collected at three sites with tall vegetation. The obtained deposition velocities ranged from 0.8 to 1.3cms⁻¹ at roadside sites and from 0.4 to 0.5cms⁻¹ at the other sites. With reference to the whole canopy, additional deposition velocities of about 0.5cms⁻¹ were obtained for leaf surfaces. As a consequence, it can be concluded that vegetation-covered areas beside streets show the highest potential to capture particles in urban areas.
Show more [+] Less [-]Polycyclic aromatic hydrocarbons in urban soils of Beijing: Status, sources, distribution and potential risk
2011
Peng, Chi | Chen, Weiping | Liao, Xiaolan | Wang, Meie | Ouyang, Z. (Zhiyun) | Jiao, Wentao | Bai, Yang
We studied the source, concentration, spatial distribution and health risk of 16 polycyclic aromatic hydrocarbons (PAHs) in urban soils of Beijing. The total mass concentration of 16 PAHs ranged from 93 to 13 141 μg kg⁻¹ with a mean of 1228 μg kg⁻¹. The contour map of soil PAH concentrations showed that the industrial zone, the historical Hutong district and the university district of Beijing have significantly higher concentrations than those in remainder of the city. The results of sources identification suggested that the primary sources of PAHs were vehicle exhaust and coal combustion and the secondary source was the atmospheric deposition of long-range transported PAHs. The incremental lifetime cancer risks (ILCRs) of exposing to PAHs in the urban soils of Beijing for adult were 1.77 × 10⁻⁶ and 2.48 × 10⁻⁵, respectively under normal and extreme conditions. For child, they were 8.87 × 10⁻⁷ and 6.72 × 10⁻⁶, respectively under normal and extreme conditions.
Show more [+] Less [-]Sequestration of organochlorine pesticides in soils of distinct organic carbon content
2011
Zhang, Na | Yang, Yu | Tao, Shu | Liu, Yan | Shi, Ke-Lu
In the present study, five soil samples with organic carbon contents ranging from 0.23% to 7.1% and aged with technical dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) for 15 months were incubated in a sealed chamber to investigate the dynamic changes of the OCP residues. The residues in the soils decreased over the incubation period and finally reached a plateau. Regression analysis showed that degradable fractions of OCPs were negatively correlated with soil organic carbon (SOC) except for α-HCH, while no correlation was found between degradation rate and SOC, which demonstrated that SOC content determines the OCP sequestration fraction in soil. Analysis of the ratio of DDT and its primary metabolites showed that, since it depends on differential sequestration among them, magnitude of (p,p′-DDE + p,p′-DDD)/p,p′-DDT is not a reliable criterion for the identification of new DDT sources.
Show more [+] Less [-]Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: Impacts of river discharge and aquaculture activities
2011
Zou, Shichun | Xu, Weihai | Zhang, Ruijie | Tang, Jianhui | Chen, Yingjun | Zhang, Gan
The presence of 21 antibiotics in six different groups was investigated in coastal water of the Bohai Bay. Meantime, to illuminate the potential effects caused by the river discharge and aquaculture activities, wastewater from three breeding plants and surface water from six rivers flowing into the Bohai Bay were also analyzed for the selected antibiotics. The result revealed that measured antibiotics in the North Bobai Bay were generally higher than those in the South, highlighting the remarkable effects of high density of human activities on the exposure of antibiotics in environment. The antibiotics found in the six rivers were generally higher than those in the Bohai Bay reflecting the important antibiotics source of river discharge. This study reveals that the high consumption of some antibiotics in aquaculture activities may pose high ecological risk to the bay.
Show more [+] Less [-]The efficiency of tobacco Bel-W3 and native species for ozone biomonitoring in subtropical climate, as revealed by histo-cytochemical techniques
2011
Alves, Edenise S. | Moura, Bárbara B. | Pedroso, Andrea N.V. | Tresmondi, Fernanda | Domingos, Marisa
We aimed to verify whether hydrogen peroxide (H₂O₂) accumulation and cell death are detected early in three bioindicators of ozone (O₃), Nicotiana tabacum ‘Bel-W3’, Ipomoea nil ‘Scarlet O’Hara’ and Psidium guajava ‘Paluma’, and whether environmental factors also affect those microscopic markers. The three species were exposed to chronic levels of O₃ in a subtropical area and a histo-cytochemical technique that combines 3,3′-diaminobenzidine (DAB) with Evans blue staining was used in the assessments. The three species accumulated H₂O₂, but a positive correlation with O₃ concentration was only observed in N. tabacum. A positive correlation between O₃ and cellular death was also observed in N. tabacum. In I. nil and P. guajava, environmental factors were responsible for symptoms at the microscopic level, especially in P. guajava. We conclude that the most appropriate and least appropriate bioindicator plant for O₃ monitoring in the subtropics are N. tabacum ‘Bel-W3’ and P. guajava ‘Paluma’, respectively.
Show more [+] Less [-]Ethylenediurea (EDU): A research tool for assessment and verification of the effects of ground level ozone on plants under natural conditions
2011
Manning, William J. | Paoletti, Elena | Sandermann, Heinrich, Jr | Ernst, Dieter
Ethylenediurea (EDU) has been widely used to prevent ozone (O₃) injury and crop losses in crop plants and growth reductions in forest trees. Successful use requires establishing a dose/response curve for EDU and the proposed plant in the absence of O₃ and in the presence of O₃ before initiating multiple applications to prevent O₃ injury. EDU can be used to verify foliar O₃ symptoms in the field, and to screen plants for sensitivity to O₃ under ambient conditions. Despite considerable research, the mode of action of EDU remains elusive. Additional research on the mode of action of EDU in suppressing O₃ injury in plants may also be helpful in understanding the mode of action of O₃ in causing injury in plants.
Show more [+] Less [-]Quantification of nitrate leaching from German forest ecosystems by use of a process oriented biogeochemical model
2011
Kiese, Ralf | Heinzeller, Christoph | Werner, Christian | Wochele, Sandra | Grote, Rüdiger | Butterbach-Bahl, Klaus
Simulations with the process oriented Forest-DNDC model showed reasonable to good agreement with observations of soil water contents of different soil layers, annual amounts of seepage water and approximated rates of nitrate leaching at 79 sites across Germany. Following site evaluation, Forest-DNDC was coupled to a GIS to assess nitrate leaching from German forest ecosystems for the year 2000. At national scale leaching rates varied in a range of 0–>80 kg NO₃–N ha⁻¹ yr⁻¹ (mean 5.5 kg NO₃–N ha⁻¹ yr⁻¹). A comparison of regional simulations with the results of a nitrate inventory study for Bavaria showed that measured and simulated percentages for different nitrate leaching classes (0–5 kg N ha⁻¹ yr⁻¹:66% vs. 74%, 5–15 kg N ha⁻¹ yr⁻¹:20% vs. 20%, >15 kg N ha⁻¹ yr⁻¹:14% vs. 6%) were in good agreement. Mean nitrate concentrations in seepage water ranged between 0 and 23 mg NO₃–N l⁻¹.
Show more [+] Less [-]Distribution, speciation and availability of antimony (Sb) in soils and terrestrial plants from an active Sb mining area
2011
Okkenhaug, Gudny | Zhu, Yong-Guan | Luo, Lei | Lei, Ming | Li, Xi | Mulder, Jan
Here, we present one of the first studies investigating the mobility, solubility and the speciation-dependent in-situ bioaccumulation of antimony (Sb) in an active Sb mining area (Xikuangshan, China). Total Sb concentrations in soils are high (527–11,798 mg kg⁻¹), and all soils, including those taken from a paddy field and a vegetable garden, show a high bioavailable Sb fraction (6.3–748 mg kg⁻¹), dominated by Sb(V). Elevated concentrations in native plant species (109–4029 mg kg⁻¹) underpin this. Both chemical equilibrium studies and XANES data suggest the presence of Ca[Sb(OH)₆]₂, controlling Sb solubility. A very close relationship was found between the citric acid extractable Sb in plants and water or sulfate extractable Sb in soil, indicating that citric acid extractable Sb content in plants may be a better predictor for bioavailable Sb in soil than total acid digestible Sb plant content.
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