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The Geochemistry of Ombrotrophic Sphagnum Species Growing in Different Microhabitats Of Eight German and Belgian Peat Bogs and the Regional Atmospheric Deposition
2007
Kempter, Heike | Frenzel, Burkhard
Comparing today's atmospheric deposition records with the elemental concentration and the net-uptake rates of ombrotrophic Sphagnum mosses from eight German and Belgian peat bogs revealed that most of all the quality and number of regularly obtained deposition monitoring data is not satisfactory. Moreover, it seems likely that the deposition rate, determined by Sphagnum mosses, does not reliably reflect the record of the total open field deposition indicated by the deposition monitoring data. The moss data, too, show a distinct spatial variability possibly because the geochemistry of peat mosses differs according to the annual growth in height, the total surface area and the surface roughness of the receptor 'peat moss' (special interception deposition). Increased Ti concentration values, for example, combined with a high annual growth rate in height at the hollow moss S. cuspidatum resulted in generally high Ti net-uptake rates and a high Ti inventory (total Ti in sample). We, therefore, suggest that productive Sphagnum species might be able to fix more Ti particles on their larger surface area than less productive species do. Moreover, the results demonstrate that for reliably calculating Sphagnum elemental net-uptake rates, as well as for all quantification of Sphagnum or peat geochemistry on a time and area basis, an accurate knowledge of the period the collected samples were exposed to atmospheric deposition is required. In particular, to do reliable reconstructions of past atmospheric deposition rates using peat deposits, further studies are needed to precisely specify the spatial variability in the geochemistry of living Sphagnum mosses.
Show more [+] Less [-]Paleolimnological Records of Nutrient and Metal Profiles in Prehistoric, Historic and Modern Sediments of Three Lakes in North-eastern Germany
2007
Selig, U. | Leipe, T (Thomas) | Dörfler, W (Walter)
Sedimentprofiles of the last 4,000-14,000 years are presented from three dimictic lakes in Mecklenburg-Vorpommern (North-eastern Germany). Sedimentological composition, major trace elements and nutrients as well as parameter for core chronology (palynology, ¹⁴C-AMS) were investigated in order to reconstruct the historical development of the lakes during the Holocene. Palynological results reflect different human settlement phases and environmental changes from the late Pleistocene to the Subatlantic. Since the Middle Ages, a permanent settlement in the catchment area resulted in higher sedimentation rates in the three lakes. Variations in sediment composition like organic matter, carbonate and mineral content were caused by different land management techniques and natural changes in the catchment area. The phosphorus accumulation increased in the upper sediment layers, but the highest phosphorus accumulations were not found in the industrial phase, but in older sediments associated with human settlement activities in the catchment area. The heavy metals lead and zinc increase in the uppermost part of all three lakes reflecting the atmospheric anthropogenic input during the last 150-200 years.
Show more [+] Less [-]Hydrochemical Effects of Surface Liming, Controlled Drainage and Lime-Filter Drainage on Boreal Acid Sulfate Soils
2007
Åström, Mats | Österholm, Peter | Bärlund, Ilona | Tattari, Sirkka
On the coastal plains of Finland there are approximately 3,000 km² of acid sulfate soils developed as a result of intensive agricultural drainage of waterlogged sulfide-bearing sediments. The runoff from these soils contains very high amounts of acidity and metals that have severely deteriorated the aquaculture in several downstream rivers and estuaries. Therefore, there is an urgent need to develop and test more environmental friendly ways of draining landscapes underlain with these nasty soils. In this study, over a 3-year monitoring period the effect of excess surface liming, controlled drainage and lime filter drainage of acid sulfate soils on runoff water quality (pH, sulfate, metals) was determined and assessed. The results showed that (1) the liming measures had not prevented severely acidic and metal-rich waters from forming and discharging from the soils, (2) the controlled drainage system might have reduced discharge peaks but its potential effects on the discharged water quality were nondetectable due to its small effect on the groundwater level and naturally inherited heterogeneities, and (3) the spatial and temporal variations identified for the various hydrochemical determinants were not caused by the kind of treatment applied. Therefore, on acid sulfate soil fields, like the one studied here, the short-term hydrochemical effects of the treatments tested are minor (or nonexistent) at least as long as the controlled drainage systems are not technically improved or better maintained.
Show more [+] Less [-]The Effect of Soil Bacteria and Perlite on Plant Growth and Soil Properties in Metal Contaminated Samples
2007
Sager, M. | Park, Jin Hee | Chon, Hyo Taek
In order to achieve remediation of contaminated substrates, phyto-extraction in pot experiments utilizing lettuce seedlings as universal accumulator plants was investigated. As test substrates, mine tailings from Shiheung and Okdong mines in Korea (particularly high in Pb, Zn, Cu, and Cd), as well as samples from historic mining site at Oberzeiring in Austria (particularly high in Pb, Sb and As) were used, and compared with adjacent farmland soils. After 21 days of growth in the test substrate, the lettuce plants were harvested, and the adjacent soils parted in bulk and root soils. Special soil bacteria, adapted to high Cd levels (Exiguobacter sp.) and capable of adsorbing large amounts of cadmium from solution, as well as perlite (Samson Perlite Inc.) were added to the test substrates before plant growth. Speciation changes in the solids were investigated by sequential leaching, utilizing neutral MgCl₂ (exchangeable), 0.16 M acetic acid, hydroxylamine pH 2, oxalate pH 3, H₂O₂ oxidation, and reflux with aqua regia. Plant growth induced differentiation between root and bulk soils, the differences were more pronounced for the non-contaminated controls. The iron-hydroxide phase increased about 30%, and also the amount of iron-hydroxide bound Be, Cd, Co, Cu, Mg, Mo, Sb and V concentrations, coming mainly from less mobile fractions. The Mn hydroxide phase, however (hydroxylamine), remained rather constant. After plant growth, the root soils were significantly lower in available P, and significantly higher in available Ca, Mn, and Na than the corresponding bulk soils. Addition of Cd-adapted soil bacteria led to a severe decrease of plant yield, but metal uptake changed in both directions. Exchangeable P in both root and bulk soil decreased, and Be, Co, Cr, Fe, K, Li, Mg, Mn, Ni, and Sr in the residual organic fraction increased. This can be interpreted as competition for nutrients, dissolution of residuals by bacterial action, and adsorption to a tightly bound biomass. Addition of perlite hardly affected the plant yield, and again metal uptake changed in both directions, but led to a decrease of siderophilic elements in the Fe- and Mn hydroxides of the bulk soil. In the root soil, perlite addition above all decreased available K, P and As, with respect to the untreated samples. Bacteria addition to perlite treated soils shifted some elements from weak acid mobile towards less available fractions.
Show more [+] Less [-]Study on Metsulfuron-Methyl Degradation in Simulated Wheat (Triticum Asetivum L.) Rhizospheric Soil with Penicillium sp. Inoculation
2007
He, Yong Hua | Shen, Dong Sheng | Hu, Li Fang | Zhu, Yin Mei
The rapid biodegradation of metsulfuron-methyl in contaminated soil was studied in this paper. The wheat (Triticum aestivum L.) rhizosphere was well simulated by setting up a hydroponic system that allowed the aseptic wheat root exudates flow onto columns containing soil previously contaminated with metsulfuron-methyl. The root-colonizing strain Penicillium sp. containing highly effective degrading plasmid on metsulfuron-methyl was inoculated in the soil, with the bulk and sterile ones as control. In soil from columns that received root exudates from a planted (versus an unplanted) apparatus, there was a significant increase in the growth of the tolerant fungi and the degradation of metsulfuron-methyl. On the other hand, the inoculation of Penicillium sp. also notably enhanced the degradation of the target herbicide. The extent of stimulation was more than twice of that measured in bulk soil. The fastest rate of disappearance of the xenobiotic occurred in the amended inoculated microcosms with 8.6 days of the half-life. The main types of low molecular weight organic acids and amino acids in the root exudates was determined to be oxalic acid, succinic acid and threonine, alanine, proline, methionine, lysine, isoleucine and leucine. What's more, by means of applying metsulfuron-methyl once again, the acclimated soil microorganisms with Penicillium sp. inoculation could sustainable rapid degrade metsulfuron-methyl. The results show that inoculation of the root-colonizing Penicillium sp. in wheat rhizosphere may be an effective approach for the rapid detoxification of soil metsulfuron-methyl contamination.
Show more [+] Less [-]Plant Colonization and Arsenic Uptake on High Arsenic Mine Wastes, New Zealand
2007
Craw, Dave | Rufaut, Cathy | Haffert, Laura | Paterson, Lorraine
Substrates associated with two historic gold mining sites in north Westland, New Zealand, have locally very high arsenic concentrations (commonly 10-40 wt% As). The substrates consist of iron oxyhydroxide precipitates, and processing mill residues. Waters associated with some of these substrates have high dissolved arsenic (commonly 10-50 mg/L As). Natural revegetation of these very high arsenic sites has occurred over the past 50 years, although some areas of substrate remain bare. Revegetating species include native and adventive shrubs, adventive grasses, rushes, and mosses, and native ferns. Revegetation by higher plants follows initial colonization by mosses, and some shrubs are growing directly in high-arsenic substrate. Shrubs, especially manuka (Leptospermum scoparium), gorse (Ulex europaeus), tree fuchsia (Fuchsia excorticata) and broadleaf (Griselinia littoralis) largely exclude arsenic from their shoots (< 10 mg/kg dry weight) irrespective of the As content of the substrate. Likewise, most grasses, and reeds (Juncus spp.), have only modest As contents (typically < 100 mg/kg dry weight). However, mosses growing on high-arsenic substrates have strongly elevated arsenic contents (> 0.2% dry weight). In particular, the moss Pohlia wahlenbergii acts as a hyperaccumulator, with up to 3% (dry weight) As. Antimony (Sb) contents of all plants are about one thousandth of that of arsenic, reflecting the As/Sb ratio of the substrates. Plant establishment in the high-As substrates may be locally limited by low nutrient status, rather than arsenic toxicity. The shrubs, grasses, and reeds identified in this study are arsenic tolerant and largely exclude arsenic from their shoots so that revegetation with these species, can help to isolate the high-arsenic substrates from the surface environment. These species could be used as phytostabilisation agents on high-arsenic sites that are remote from human habitation. In contrast, the mosses, despite their high arsenic tolerance, are a less desirable component of revegetation of high-arsenic substrates because they actively transfer arsenic from the substrate to the biosphere.
Show more [+] Less [-]Speciation and Seasonal Variations of Dissolved Inorganic Arsenic in Jiaozhou Bay, North China
2007
Ren, J. L | Zhang, J | Li, D. D | Cheng, Y | Liu, S. M
The distributions and biogeochemical cycles of arsenic in the aquatic environment have captured the interest of geochemists due to arsenic's multiple chemical forms, the toxicity of certain arsenic species and large anthropogenic input. Seasonal variations in the dissolved inorganic arsenic concentration and speciation in Jiaozhou Bay, which is located on the west coast of the Yellow Sea in northern China, are presented here. Three cruises were carried out in Jiaozhou Bay under varying tidal regimes, one at neap tide and one at spring tide in August and one at spring tide in October of 2001. In addition to the transect surveys, the main sources of dissolved inorganic arsenate and arsenite in Jiaozhou Bay, including riverine input from five major tributary rivers, atmospheric dry and wet depositions, and groundwater and wastewater input, were collected in different seasons to estimate arsenic transport through different sources. The mean concentrations of total dissolved inorganic arsenic (TDIAs, As (V+III)) in Jiaozhou Bay were statistically comparable between summer and autumn, with higher concentrations at the northwest and northeast parts of the bay, reflecting human activities. The As (III)/TDIAs ratio ranged between 0.045 and 0.68, with an average of 0.16, implying that arsenate was the dominating species in Jiaozhou Bay. A preliminary box model was established to estimate the water-mass balance and arsenic budgets for Jiaozhou Bay, which demonstrated that river inputs and atmospheric depositions were the main sources of arsenic into Jiaozhou Bay. The concentrations of dissolved inorganic arsenic in Jiaozhou Bay have decreased in the last two decades. Compared with other areas in the world, the concentration of arsenic in Jiaozhou Bay remains at the natural level and this region can be characterized as a less disturbed area.
Show more [+] Less [-]Field Intercomparison of Main Components in Air in EMEP
2007
Aas, Wenche | Schaug, Jan | Hanssen, Jan Erik
Within the European monitoring network (EMEP, http://www.emep.int) several different sampling procedures for measuring the main air components have been applied. This has contributed to systematic concentration differences and a comparability problem. Since 1997 co-located experiments in 15 countries have been carried out to quantify these differences. In addition, three major measurement campaigns were organized by EMEP between 1985 and 1991. Differences among results depend on the concentration level and methods used. The decrease in SO₂ concentrations over the last twenty years has placed greater demands on the methodology. Absorbing solutions methods for SO₂, (H₂O₂ and tetrachloromercurate (TCM)) typically have higher detection limits than the reference method, which uses KOH impregnated filters. The TCM method also has problems with negative interference, especially in summertime. UV fluorescence monitors have in a few cases proven to give good results, but interferences, detection limit and poor maintenance can be problems. For NO₂, many countries are using the TGS absorption solution method, which has a higher detection limit than the reference method using NaI impregnated glass sinters. The Salzmann method gives unreliable results at concentrations below 1 μgN/m³, and even at higher concentrations the uncertainty is rather unsatisfactory. The chemiluminescence monitor with molybdenum converters tends to systematically overestimate NO₂ concentrations, possibly because zero-drift problems and the non-specific response to NO₂. Particulate sulphate measurements in general have lower bias and uncertainties than gas and other aerosol measurements.
Show more [+] Less [-]Study of the Levels of Concentration of As, Cd and Ni in a Ceramic Cluster
2007
Pallarés, S. | Vicente, A. B. | Jordan, M. M. | Sanfeliu, T.
The main objective of this paper is to check the fulfilment of the European Directive 2004/107/CE, which refers to the limit values of arsenic, cadmium and nickel that will have to be carried out the first of January 2010. Three sampling points have been chosen (Alcora, Vila-real and Castellón), forming a triangle that comprise most of the ceramic cluster of the province of Castellón (Spain). This is a problematic area in relation to the fulfilment of the directive, due to its high industrial development. Apart from this main objective, the following are raised: a) The analysis of the temporal evolution of the levels of As, Cd, Ni and PM10 in the atmosphere during the year 2002; b) The identification of similar behaviour patterns and of the possible common origins in the studied pollutants; c) To show the existence of differences in the behaviour and evolution of As, Cd, Ni and PM10 in the atmospheric medium depending on the location of the sampling point; d) To check whether the levels of As, Cd, Ni and PM10 are influenced by the environmental temperature. The concentration levels of arsenic, cadmium and nickel in Alcora, Vila-real and Castellón have been determined during the year 2002, in order to check whether they are below the limits established in the future directive on these elements. The following conclusions are reached from the results obtained after the chemical analysis (using ICP–MS) of the samples collected in the three locations.
Show more [+] Less [-]Complexation of Copper by Sewage Sludge-derived Dissolved Organic Matter: Effects on Soil Sorption Behaviour and Plant Uptake
2007
Ashworth, D. J. | Alloway, B. J.
The complexation of Cu by sewage sludge-derived dissolved organic matter (SSDOM) is a process by which the environmental significance of the element may become enhanced due to reduced soil sorption and, hence, increased mobility. The work described in this paper used an ion selective electrode procedure to show that SSDOM complexation of Cu was greatest at intermediate pH values because competition between hydrogen ions and Cu for SSDOM binding sites, and between hydroxyl ions and SSDOM as Cu ligands, was lowest at such values. Batch sorption experiments further showed that the process of Cu complexation by SSDOM provided an explanation for enhanced desorption of Cu from the solid phase of a contaminated, organic matter-rich, clay loam soil, and reduced adsorption of Cu onto the solid phase of a sandy loam soil. Complexation of Cu by SSDOM did not affect uptake of Cu by spring barley plants, when compared to free ionic Cu, in a sand-culture pot experiment. However, it did appear to lead to greater biomass yields of the plant; perhaps indicating that the Cu-SSDOM complex had a lower toxicity towards the plant than the free Cu ion.
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