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Spatio-temporal trends of nitrogen deposition and climate effects on Sphagnum productivity in European peatlands
2014
Granath, Gustaf | Limpens, Juul | Posch, Maximilian | Mücher, Sander | de Vries, Wim
To quantify potential nitrogen (N) deposition impacts on peatland carbon (C) uptake, we explored temporal and spatial trends in N deposition and climate impacts on the production of the key peat forming functional group (Sphagnum mosses) across European peatlands for the period 1900–2050. Using a modelling approach we estimated that between 1900 and 1950 N deposition impacts remained limited irrespective of geographical position. Between 1950 and 2000 N deposition depressed production between 0 and 25% relative to 1900, particularly in temperate regions. Future scenarios indicate this trend will continue and become more pronounced with climate warming. At the European scale, the consequences for Sphagnum net C-uptake remained small relative to 1900 due to the low peatland cover in high-N areas. The predicted impacts of likely changes in N deposition on Sphagnum productivity appeared to be less than those of climate. Nevertheless, current critical loads for peatlands are likely to hold under a future climate.
Показать больше [+] Меньше [-]Soil physical characteristics after EDTA washing and amendment with inorganic and organic additives
2014
Zupanc, Vesna | Kastelec, Damijana | Lestan, Domen | Grcman, Helena
Soil washing has been established as suitable remediation technology, with most research focused on metal removing efficiency and toxic effect on plants, less on the influence on soil physical characteristics, which was the focus of this study. In soil column experiment highly contaminated soil and soil washed with EDTA, mixed with additives (gypsum, hydrogel, manure, peat) were tested. White clover was used as a soil cover. Yield, metal concentration in soil and plant, aggregate fractionation and stability, saturated hydraulic conductivity and soil water retention of the soil were measured. Soil washing decreased metal concentration in soil and plants, but yield of white clover on remediated soil was significantly lower compared to the original soil. Significant differences in water retention characteristics, aggregate fractionation and stability between original and remediated soil have been determined. Gypsum, hydrogel and peat increased plant available water, manure and peat increased yield on remediated soil.
Показать больше [+] Меньше [-]Peat-fire-related air pollution in Central Kalimantan, Indonesia
2014
Hayasaka, Hiroshi | Noguchi, Izumi | Putra, Erianto Indra | Yulianti, Nina | Vadrevu, Krishna
The past decade marked record high air pollution episodes in Indonesia. In this study, we specifically focus on vegetation fires in Palangkaraya located near a Mega Rice Project area in Indonesia. We analyzed various gaseous air pollution data such as particulate matter (PM10), SO2, CO, O3, and NO2 study region. We also conducted elemental analysis at two different sites. Results from 2001 to 2010 suggested the longest hazardous air pollution episode during 2002 lasting about 80 days from mid-August to late-October. Maximum peak concentrations of PM10, SO2, CO, and O3 were also observed during 2002 and their values reached 1905, 85.8, 38.3, and 1003 × 10−6 gm−3 respectively. Elemental analysis showed significant increase in concentrations during 2011 and 2010. Satellite retrieved fires and weather data could explain most of the temporal variations. Our results highlight peat fires as a major contributor of photochemical smog and air pollution in the region.
Показать больше [+] Меньше [-]The Use of Natural Sorbents for Spilled Crude Oil and Diesel Cleanup from the Water Surface
2014
Paulauskienė, T. | Jucikė, I. | Juščenko, N. | Baziukė, D.
Oil spills impose serious damage to the environment. A spilled crude oil or its products affect aquatic flora and fauna and influence the atmosphere as well. Such pollutants are especially dangerous for the water ecosystems, where biological self-purification processes are slower (for example the Baltic Sea), than in warmer regions. In this paper, we evaluate a sorption capacity of ecologically friendly natural sorbents, when the crude oil and diesel are spilled on the surface of water. The experiments are carried out in the laboratory, and the water from the Lithuanian Baltic Sea coastline and Curonian Lagoon is used. Moss, straw, wool, sawdust, and peat are the natural sorbents evaluated during the experiments. Chromatographic analysis of crude oil and diesel during the process of sorption was conducted as well. An experiment with some synthetic sorbents was carried out to compare the results with natural ones. The experiments showed that the most suitable material for crude oil or diesel fuel spilled on the water surface is peat. As well, Lagergren’s model was adopted to the case of the sorption processes we have investigated. It can be exploited as a decision support tool while deciding the required time interval to achieve maximum sorption capacity of the sorbent in use.
Показать больше [+] Меньше [-]Assessment of Lead Contamination in Peatlands Using Field Portable XRF
2014
Shuttleworth, E. L. | Evans, M. G. | Hutchinson, S. M. | Rothwell, J. J.
Ombrotrophic peatlands are highly sensitive to atmospheric heavy metal deposition. Previous attempts to quantify peatland lead pollution have been undertaken using the inventory approach. However, there can be significant within-site spatial heterogeneity in lead concentrations, highlighting the need for multiple samples to properly quantify lead storage. Field portable x-ray fluorescence (FPXRF) continues to gain acceptance in the study of contaminated soil, but has not thus far been used to assess peatland lead contamination. This study compares lead concentrations in surface peat samples from the South Pennines (UK) derived using (a) FPXRF in the field, (b) FPXRF in the lab on dried samples and (c) ICP-OES analysis. FPXRF field and lab data are directly comparable when field measurements are corrected for water content, both can be easily used to estimate acid extractable lead using regression equations. This study is a successful demonstration of FPXRF as a tool for a time- and cost-effective means of determining the lead content of contaminated peatlands, which will allow rapid landscape scale reconnaissance, core logging, surface surveys and sediment tracing.
Показать больше [+] Меньше [-]Distribution and Pools of Mercury in Czech Forest Soils
2014
Navratil, Tomas | Shanley, Jamie | Rohovec, Jan | Hojdová, Maria | Penížek, Vít | Buchtová, Jana
Parts of the Czech Republic received extreme loading of acid deposition from coal combustion in the second half of the twentieth century. Although associated Hg deposition was not directly measured, Hg deposition rates calculated from peat cores approach 100 μg m⁻² year⁻¹. We quantified the soil concentrations and pools of Hg with carbon (C), sulfur (S), and nitrogen (N)—elements closely associated with soil organic matter at five sites across the Czech Republic—four sites known for extreme deposition levels of S and N compounds in the twentieth century, and one site relatively less impacted. The site-specific means of O-horizon Hg concentrations ranged from 277 to 393 μg kg⁻¹, while means of Hg concentrations in mineral soil ranged from 22 to 95 μg kg⁻¹. The mean Hg/C ratio across sites increased from ∼0.5 μg Hg g⁻¹C in the Oi-horizon to ∼5 μg Hg g⁻¹C in the C-horizon due to the progressive mineralization of soil organic matter. The soil Hg/C increase was accompanied by a soil C/N decrease, another indicator of soil organic matter mineralization. Soil Hg/C also increased as soil C/S decreased, suggesting that Hg was stabilized by S functional groups within the soil organic matter. Mineral soil Hg pools (8.9–130.0 mg m⁻²) dominated over organic soil Hg pools (5.3–10.1 mg m⁻²) at all sites. Mineral soil Hg pools correlated more strongly with total soil S and oxalate-extractable Fe than with total soil C. Total soil Hg pools could be accounted for by a time period of atmospheric inputs that was short relative to the age of the soils. The cross site variability of Hg soil pools was not sensitive to the local Hg deposition history but rather related to the capacity of soil to store and stabilize organic matter.
Показать больше [+] Меньше [-]Influence of sediment composition on PAH toxicity using zebrafish (Danio rerio) and Japanese medaka (Oryzias latipes) embryo-larval assays
2014
Perrichon, Prescilla | Le Bihanic, Florane | Bustamante, Paco | Le Menach, Karyn | Budzinski, Hélène | Cachot, Jérôme | Cousin, Xavier
Due to hydrophobic and persistent properties, polycyclic aromatic hydrocarbons (PAHs) have a high capacity to accumulate in sediment. Sediment quality criteria, for the assessment of habitat quality and risk for aquatic life, include understanding the fate and effects of PAHs. In the context of European regulation (REACH and Water Framework Directive), the first objective was to assess the influence of sediment composition on the toxicity of two model PAHs, benzo[a]pyrene and fluoranthene using 10-day zebrafish embryo-larval assay. This procedure was undertaken with an artificial sediment in order to limit natural sediment variability. A suitable sediment composition might be then validated for zebrafish and proposed in a new OECD guideline for chemicals testing. Second, a comparative study of toxicity responses from this exposure protocol was then performed using another OECD species, the Japanese medaka. The potential toxicity of both PAHs was assessed through lethal (e.g., survival, hatching success) and sublethal endpoints (e.g., abnormalities, PMR, and EROD) measured at different developmental stages, adapted to the embryonic development time of both species. Regarding effects observed for both species, a suitable artificial sediment composition for PAH toxicity testing was set at 92.5 % dry weight (dw) silica of 0.2–0.5-mm grain size, 5 % dw kaolin clay without organic matter for zebrafish, and 2.5 % dw blond peat in more only for Japanese medaka. PAH bioavailability and toxicity were highly dependent on the fraction of organic matter in sediment and of the Kₒwcoefficients of the tested compounds. The biological responses observed were also dependent of the species under consideration. Japanese medaka embryos appeared more robust than zebrafish embryos for understanding the toxicity of PAHs following a sediment contact test, due to the longer exposure duration and lower sensitivity of sediment physical properties.
Показать больше [+] Меньше [-]Pseudomorphs of barite and biogenic ZnS after phyto-crystals of calcium oxalate (whewellite) in the peat layer of a poor fen
2014
Smieja-Król, Beata | Janeczek, Janusz | Wiedermann, Jerzy
Pseudomorphs of barite (BaSO₄) and Cd-rich ZnS after whewellite (CaC₂O₄·H₂O) occur within remnants of Scots pine bark tissues in the peat layer of a poor fen located near a zinc smelter in south Poland. A two-step formation of the pseudomorphs is postulated based on SEM observations: (1) complete dissolution of whewellite, possibly caused by oxalotrophic bacteria, and (2) subsequent bacterially induced precipitation of barite and spheroidal aggregates of ZnS together with galena (PbS) in voids left by the dissolved whewellite crystals. Local increase in pH due to microbial degradation of whewellite, elevated concentrations of Zn(II) and Ba(II) in pore water due to the decomposition of atmospheric particles of sphalerite and barite in the acidic (pH 3.5–3.8) environment, oxidation of S species during drying and rewetting of the peat layer, and subsequent partial reduction of sulfate anions by sulfur-reducing bacteria were all factors likely involved in the crystallization of ZnS and barite in the microenvironment of the post-whewellite voids.
Показать больше [+] Меньше [-]Filter materials for metal removal from mine drainage—a review
2014
Westholm, Lena Johansson | Repo, Eveliina | Sillanpää, Mika
A large number of filter materials, organic and inorganic, for removal of heavy metals in mine drainage have been reviewed. Bark, chitin, chitosan, commercial ion exchangers, dairy manure compost, lignite, peat, rice husks, vegetal compost, and yeast are examples of organic materials, while bio-carbons, calcareous shale, dolomite, fly ash, limestone, olivine, steel slag materials and zeolites are examples of inorganic materials. The majority of these filter materials have been investigated in laboratory studies, based on various experimental set-ups (batch and/or column tests) and different conditions. A few materials, for instance steel slag materials, have also been subjects to field investigations under real-life conditions. The results from these investigations show that steel slag materials have the potential to remove heavy metals under different conditions. Ion exchange has been suggested as the major metal removal mechanisms not only for steel slag but also for lignite. Other suggested removal mechanisms have also been identified. Adsorption has been suggested important for activated carbon, precipitation for chitosan and sulphate reduction for olivine. General findings indicate that the results with regard to metal removal vary due to experimental set ups, composition of mine drainage and properties of filter materials and the discrepancies between studies renders normalisation of data difficult. However, the literature reveals that Fe, Zn, Pb, Hg and Al are removed to a large extent. Further investigations, especially under real-life conditions, are however necessary in order to find suitable filter materials for treatment of mine drainage.
Показать больше [+] Меньше [-]Preparation of petroleum-degrading bacterial agent and its application in remediation of contaminated soil in Shengli Oil Field, China
2014
Yu, Yang | Zhang, Wen | Chen, Guanhong | Gao, Yongchao | Wang, Jianing
Two petroleum-degrading strains were screened from oil fields and denoted as SWH-1 (Bacillus subtilis) and SWH-2 (Sphingobacterium multivorum), which were used to ferment and prepare bacterial agent to remediate petroleum-contaminated sites in Shengli Oil Field in China. The optimal liquid fermentation medium and conditions were MgSO₄·7H₂O (0.5 %), NaCl (0.5 %), soybean dregs (3 %), pH 7.0, culturing at 30 °C, and 220 r/min for 16 h. Peat was chosen as the bacterial carrier due to its ability of keeping microbial activity. Mixed fermented liquid was added into peat (1:2) and air-dried, and the bacterial agent was obtained. It was applied to the petroleum-contaminated soil, which was irrigated, tilled, and fertilized. The removal rate reached 67.7 % after 2 months of remediation. During remediation, the quantity of indigenous bacteria varied a lot, while the inoculated bacteria remained stable; the dehydrogenase activity was at high levels and then decreased. Indigenous microorganisms, inoculated bacterial agent, nutrients, water, and soil permeability all played important roles. The study prepared an environment-friendly bacterial agent and established a set of bioremediation technique, which provided further insights into integration of fermentation engineering and soil remediation engineering.
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