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Assessment of atmospheric sulfur with the epilithic moss Haplocladium microphyllum: Evidences from tissue sulfur and δ34S analysis Full text
2009
Liu, Xue-Yan | Xiao, Hua-Yuan | Liu, Cong-Qiang | Xiao, Hong-Wei | Wang, Yan-Li
The application of geochemical signals in mosses is more and more popular to investigate the deposition of atmospheric pollutants, but it is unclear whether records of atmospheric sulfur in mosses differ between their diverse habitats. This study aimed to investigate the influence of growing condition on tissue sulfur and δ³⁴S of Haplocladium microphyllum. Epilithic and terricolous mosses in open fields, mosses under different canopy conditions were considered. We found that tissue sulfur and δ³⁴S of mosses under different habitats were not consistent and could not be compared for atmospheric sulfur research with each other even collected at the same site, moss sulfur and δ³⁴S records would be distorted by subsoil and upper canopies in different degrees, which possibly mislead the interpretation of atmospheric sulfur level and sources. Consequently, mosses on open rocks can be used reliably to assess atmospheric-derived sulfur in view of their identical sulfur and δ³⁴S evidences. Mosses on open rocky surfaces are reliable bioindicators of atmospheric sulfur deposition.
Show more [+] Less [-]Ozone and urban forests in Italy Full text
2009
Paoletti, Elena
Ozone levels along urban-to-rural gradients in three Italian cities (Milan, Florence, Bari) showed that average AOT40 values at rural and suburban sites were 2.6 times higher than those determined at urban sites. However, O3 also exceeded the European criteria to protect forest health at urban sites, even when the standards for human health protection were met. For protecting street trees in Mediterranean cities, the objectives of measurement at urban sites should extend from the protection of human health to the protection of vegetation as well. A review of forest effects on O3 pollution and of O3 pollution on forest conditions in Italian cities showed that it was not possible to distinguish the effect of O3 in the complex mixture of urban pollutants and stressors. A preliminary list of tree species for urban planning in the Mediterranean area shows the average tree capacity of O3 removal and VOC emission. European criteria to protect human health from ozone may not protect urban forests in the Mediterranean area.
Show more [+] Less [-]Pulsed gas injection: A minimum effort approach for enhanced natural attenuation of chlorobenzene in contaminated groundwater Full text
2009
Balcke, Gerd Ulrich | Paschke, Heidrun | Vogt, Carsten | Schirmer, Mario
Chlorobenzene-contaminated groundwater was used to assess pulsed gas sparging as a minimum effort aeration strategy to enhance intrinsic natural attenuation. In contrast to existing biosparging operations, oxygen was supplied at minimum rate by reducing the gas injection frequency to 0.33 day⁻¹. Field tests in a model aquifer were conducted in a 12 m long reactor, filled with indigenous aquifer material and continuously recharged with polluted groundwater over 3 years. The closed arrangement allowed yield balances, cost accounting as well as the investigation of spatial distributions of parameters which are sensitive to the biodegradation process. Depending on the injection frequency and on the gas chosen for injection (pure oxygen or air) oxygen-deficient conditions prevailed in the aquifer. Despite the limiting availability of dissolved oxygen in the groundwater, chlorobenzene degradation under oxygen-deficient conditions proved to be more effective than under conditions with dissolved oxygen being available in high concentrations. Minimum rate gas sparging resulted in sustained biodegradation of chlorobenzene in a polluted groundwater aquifer.
Show more [+] Less [-]Ultraviolet absorbance as a proxy for total dissolved mercury in streams Full text
2009
Dittman, Jason A. | Shanley, James B. | Driscoll, Charles T. | Aiken, George R. | Chalmers, Ann T. | Towse, Janet E.
Stream water samples were collected over a range of hydrologic and seasonal conditions at three forested watersheds in the northeastern USA. Samples were analyzed for dissolved total mercury (THgd), DOC concentration and DOC composition, and UV₂₅₄ absorbance across the three sites over different seasons and flow conditions. Pooling data from all sites, we found a strong positive correlation of THgd to DOC (r² = 0.87), but progressively stronger correlations of THgd with the hydrophobic acid fraction (HPOA) of DOC (r² = 0.91) and with UV254 absorbance (r² = 0.92). The strength of the UV₂₅₄ absorbance-THgd relationship suggests that optical properties associated with dissolved organic matter may be excellent proxies for THgd concentration in these streams. Ease of sample collection and analysis, the potential application of in-situ optical sensors, and the possibility for intensive monitoring over the hydrograph make this an effective, inexpensive approach to estimate THgd flux in drainage waters. Ultraviolet absorbance measurements are a cost-effective proxy to estimate dissolved mercury concentration in stream water.
Show more [+] Less [-]Leaching of hydrophobic Cu and Zn from discarded marine antifouling paint residues: Evidence for transchelation of metal pyrithiones Full text
2009
Holmes, Luke | Turner, Andrew
Leaching of Cu and Zn from a composite of discarded antifouling paint residues ([Cu] = 288 mg g−1; [Zn] = 96 mg g−1) into natural sea water has been studied over a period of 75 h. Total Cu and Zn were released according to a pseudo first-order reaction, with rate constants on the order of 0.3 and 2.5 (mg L−1)−1 h−1, respectively, and final concentrations equivalent to the dissolution of about 8 and 2% of respective concentrations in the composite. Time-distributions of hydrophobic metals, determined by solid phase extraction-methanol elution, were more complex. Net release of hydrophobic Cu was greater in the absence of light than under a sequence of light–dark cycles; however, hydrophobic Zn release was not detected under the former conditions but contributed up to 50% of total aqueous Zn when light was present. These observations are interpreted in terms of the relative thermodynamic and photolytic stabilities of biocidal pyrithione complexes. Hydrophobic Cu and Zn leached from antifouling paint particles into sea water appear to be pyrithione complexes.
Show more [+] Less [-]Quantification of activated carbon contents in soils and sediments using chemothermal and wet oxidation methods Full text
2009
Brändli, Rahel C. | Bergsli, Anders | Ghosh, Upal | Hartnik, Thomas | Breedveld, Gijs D. | Cornelissen, Gerard
Activated carbon (AC) strongly sorbs organic pollutants and can be used for remediation of soils and sediments. A method for AC quantification is essential to monitor AC (re)distribution. Since AC is black carbon (BC), two methods for BC quantification were tested for AC mixed in different soils and sediments: i) chemothermal oxidation (CTO) at a range of temperatures and ii) wet-chemical oxidation with a potassium dichromate/sulfuric acid solution. For three soils, the amount of AC was accurately determined by CTO at 375 °C. For two sediments, however, much of the AC disappeared during combustion at 375 °C, which could probably be explained by catalytic effects by sediment constituents. CTO at lower temperatures (325–350 °C) was a feasible alternative for one of the sediments. Wet oxidation effectively functioned for AC quantification in sediments, with almost complete AC recovery (81–92%) and low remaining amounts of native organic carbon (5–16%). Activated carbon quantification is best performed for soils with chemothermal oxidation at 375 °C, and for sediments with wet oxidation with potassium dichromate/sulfuric acid.
Show more [+] Less [-]Novel sampling methods for atmospheric semi-volatile organic compounds (SOCs) in a high altitude alpine environment Full text
2009
Offenthaler, I. | Jakobi, G. | Kaiser, A. | Kirchner, M. | Kräuchi, N. | Niedermoser, B. | Schramm, K.W. | Sedivy, I. | Staudinger, M. | Thanner, G. | Weiss, P. | Moche, W.
High- and low-volume active air samplers as well as bulk deposition samplers were developed to sample atmospheric SOCs under the adverse conditions of a mountain environment. Active sampling employed separate filters for different European source regions. Filters were switched depending on daily trajectory forecasts, whose accuracy was evaluated post hoc. The sampling continued on three alpine summits over five periods of four months. The prevailing trajectories varied stronger between sampling periods than between stations. The sampling equipment (active and bulk deposition) proved dependable for operation in a mountain environment, with idle times being mainly due to non-routine manipulations and connectivity. Equipment for direction-specific air sampling and bulk deposition sampling in mountains was developed and tested.
Show more [+] Less [-]A simple chemical free arsenic removal method for community water supply – A case study from West Bengal, India Full text
2009
Sen Gupta, B. | Chatterjee, S. | Rott, U. | Kauffman, H. | Bandyopadhyay, A. | DeGroot, W. | Nag, N.K. | Carbonell-Barrachina, A.A. | Mukherjee, S.
This report describes a simple chemical free method that was successfully used by a team of European and Indian scientists (www.qub.ac.uk/tipot) to remove arsenic (As) from groundwater in a village in West Bengal, India. Six such plants are now in operation and are being used to supply water to the local population (www.insituarsenic.org). The study was conducted in Kasimpore, a village in North 24 Parganas District, approximately 25 km from Kolkata. In all cases, total As in treated water was less than the WHO guideline value of 10 μg L−1. The plant produces no sludge and the operation cost is 1.0 US$ per day for producing 2000 L of potable water. This work presents the chemical free arsenic removal method from groundwater and its successful implementation in West Bengal for community water supply.
Show more [+] Less [-]How do long-term development and periodical changes of river–floodplain systems affect the fate of contaminants? Results from European rivers Full text
2009
Lair, G.J. | Zehetner, F. | Fiebig, M. | Gerzabek, M.H. | Gestel, C.A.M van | Hein, T. | Hohensinner, S. | Hsu, P. | Jones, K.C. | Jordan, G. | Koelmans, A.A. | Poot, A. | Slijkerman, D.M.E. | Totsche, K.U. | Bondar-Kunze, E. | Barth, J.A.C.
In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded “AquaTerra” project (2004–2009), we analyze changes in the dynamics of European river–floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management. Human activities have changed the hydraulics and contaminant fate in river–floodplain ecosystems.
Show more [+] Less [-]Development of a comprehensive analytical method for the determination of chlorinated paraffins in spruce needles applied in passive air sampling Full text
2009
Iozza, Saverio | Schmid, Peter | Oehme, Michael
Conifer needles are used for the monitoring of atmospheric persistent organic pollutants. The objective of the present study was to develop a method for the detection of airborne chlorinated paraffins (CPs) using spruce needles as a passive sampler. The method is based on liquid extraction of the cuticular wax layer followed by chromatographic fractionation and detection of CPs using two different GCMS techniques. Total CP concentrations (sum of short (SCCP), medium (MCCP) and long chain CPs (LCCP)) were determined by EI-MS/MS. SCCP and MCCP levels as well as congener group patterns (n-alkane chain length, chlorine content) could be evaluated using ECNI-LRMS. For the first time, data on environmental airborne CPs on spruce needles taken within the Monitoring Network in the Alpine Region for Persistent and other Organic Pollutants (MONARPOP) are presented providing evidence that spruce needles are a suitable passive sampling system for the monitoring of atmospheric CPs. A developed method for chlorinated paraffins (CPs) provided evidence that spruce needles are a suitable passive sampling system for the monitoring of atmospheric CPs.
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