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Pedogenesis, geochemical forms of heavy metals, and artifact weathering in an urban soil chronosequence, Detroit, Michigan النص الكامل
2011
Howard, Jeffrey L. | Olszewska, Dorota
An urban soil chronosequence in downtown Detroit, MI was studied to determine the effects of time on pedogenesis and heavy metal sequestration. The soils developed in fill derived from mixed sandy and clayey diamicton parent materials on a level late Pleistocene lakebed plain under grass vegetation in a humid-temperate (mesic) climate. The chronosequence is comprised of soils in vacant lots (12 and 44 years old) and parks (96 and 120 years old), all located within 100m of a roadway. An A-horizon 16cm thick with 2% organic matter has developed after only 12 years of pedogenesis. The 12 year-old soil shows accelerated weathering of iron (e.g. nails) and cement artifacts attributed to corrosion by excess soluble salts of uncertain origin. Carbonate and Fe-oxide are immobilizing agents for heavy metals, hence it is recommended that drywall, plaster, cement and iron artifacts be left in soils at brownfield sites for their ameliorating effects.
اظهر المزيد [+] اقل [-]Effects of compositional heterogeneity and nanoporosity of raw and treated biomass-generated soot on adsorption and absorption of organic contaminants النص الكامل
2011
Chen, Baoliang | Huang, Wenhai
A biomass-generated soot was sequentially treated by HCl-HF solution, organic solvent, and oxidative acid to remove ash, extractable native organic matter (EOM), and amorphous carbon. The compositional heterogeneity and nano-structure of the untreated and treated soot samples were characterized by elemental analysis, thermal gravimetric analysis, BET-N₂ surface area, and electron microscopic analysis. Sorption properties of polar and nonpolar organic pollutants onto the soot samples were compared, and individual contributions of adsorption and absorption were quantified. The sorption isotherms for raw sample were practically linear, while were nonlinear for the pretreated-soot. The removal of EOM enhanced adsorption and reduced absorption, indicating that EOM served as a partitioning phase and simultaneously masked the adsorptive sites. By drastic-oxidation, the outer amorphous carbon and the inner disordered core of the soot particles were completely removed, and a fullerene-like nanoporous structure (aromatic shell) was created, which promoted additional π–π interaction between phenanthrene and the soot.
اظهر المزيد [+] اقل [-]Direct and indirect effects of metal contamination on soil biota in a Zn–Pb post-mining and smelting area (S Poland) النص الكامل
2011
Kapusta, Paweł | Szarek-Łukaszewska, Grażyna | Stefanowicz, Anna M.
Effects of metal contamination on soil biota activity were investigated at 43 sites in 5 different habitats (defined by substratum and vegetation type) in a post-mining area. Sites were characterised in terms of soil pH and texture, nutrient status, total and exchangeable metal concentrations, as well as plant species richness and cover, abundances of enchytraeids, nematodes and tardigrades, and microbial respiration and biomass. The concentrations of total trace metals were highest in soils developed on mining waste (metal-rich dolomite), but these habitats were more attractive than sandy sites for plants and soil biota because of their higher content of organic matter, clay and nutrients. Soil mesofauna and microbes were strongly dependent on natural habitat properties. Pollution (exchangeable Zn and Cd) negatively affected only enchytraeid density; due to a positive relationship between enchytraeids and microbes it indirectly reduced microbial activity.
اظهر المزيد [+] اقل [-]Biofilm responses to marine fish farm wastes النص الكامل
2011
Sanz-Lázaro, Carlos | Navarrete-Mier, Francisco | Marín, Arnaldo
Biofilm responses to marine fish farm wastes النص الكامل
2011
Sanz-Lázaro, Carlos | Navarrete-Mier, Francisco | Marín, Arnaldo
The changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation were quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems.
اظهر المزيد [+] اقل [-]Biofilm responses to marine fish farm wastes النص الكامل
2011
Sanz-Lázaro, Carlos | Navarrete Mier, Francisco | Marín, Arnaldo | Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada | Biología Marina
The changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation were quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems. | This work was funded by the project AGL2004-08350-C02-01/ACU from the Ministerio de Ciencia y Tecnología, a predoctoral grant to C. S. from the Ministerio de Educación y Ciencia (Spain) and another predoctoral grant to F. N. from the ALBAN programme (EU).
اظهر المزيد [+] اقل [-]The influence of pH and organic matter content in paddy soil on heavy metal availability and their uptake by rice plants النص الكامل
2011
Zeng, Fanrong | Ali, Shafaqat | Zhang, Haitao | Ouyang, Younan | Qiu, Boyin | Wu, Feibo | Zhang, Guoping
The experiments were done to investigate the effect of soil pH and organic matter content on EDTA-extractable heavy metal contents in soils and heavy metal concentrations in rice straw and grains. EDTA-extractable Cr contents in soils and concentrations in rice tissues were negatively correlated with soil pH, but positively correlated with organic matter content. The combination of soil pH and organic matter content would produce the more precise regression models for estimation of EDTA-Cu, Pb and Zn contents in soils, demonstrating the distinct effect of the two factors on the availability of these heavy metals in soils. Soil pH greatly affected heavy metal concentrations in rice plants. Furthermore, inclusion of other soil properties in the stepwise regression analysis improved the regression models for predicting straw Fe and grain Zn concentrations, indicating that other soil properties should be taken into consideration for precise predicting of heavy metal concentrations in rice plants.
اظهر المزيد [+] اقل [-]Inside-sediment partitioning of PAH, PCB and organochlorine compounds and inferences on sampling and normalization methods النص الكامل
2011
Opel, Oliver | Palm, Wolf-Ulrich | Steffen, Dieter | Ruck, Wolfgang K.L.
Comparability of sediment analyses for semivolatile organic substances is still low. Neither screening of the sediments nor organic-carbon based normalization is sufficient to obtain comparable results. We are showing the interdependency of grain-size effects with inside-sediment organic-matter distribution for PAH, PCB and organochlorine compounds. Surface sediment samples collected by Van-Veen grab were sieved and analyzed for 16 PAH, 6 PCB and 18 organochlorine pesticides (OCP) as well as organic-matter content. Since bulk concentrations are influenced by grain-size effects themselves, we used a novel normalization method based on the sum of concentrations in the separate grain-size fractions of the sediments. By calculating relative normalized concentrations, it was possible to clearly show underlying mechanisms throughout a heterogeneous set of samples. Furthermore, we were able to show that, for comparability, screening at <125 μm is best suited and can be further improved by additional organic-carbon normalization.
اظهر المزيد [+] اقل [-]Is black carbon a better predictor of polycyclic aromatic hydrocarbon distribution in soils than total organic carbon? النص الكامل
2011
Agarwal, Tripti | Bucheli, Thomas D.
Black carbon (BC) and total organic carbon (TOC) were quantified in the surface soils of Switzerland (N=105) and Delhi (N=36), India, to examine their relationships with contents of polycyclic aromatic hydrocarbons (PAH). BC content in Swiss (background) soils (N=104) varied from 0.41 to 4.75mg/g (median: 1.13mg/g) and constituted 1–9% (median: 3%) of TOC. Indian (urban) soils had similar BC concentrations (0.37–2.05mg/g, median: 1.19mg/g), with relatively higher BC/TOC (6–23%, median: 13%). Similar to TOC, BC showed significant positive correlation with lighter PAH, but no correlation with heavier PAH in Swiss soils. In contrast, heavier PAH were significantly correlated only with BC in Delhi soils. It seems that TOC governs the distribution of PAH in organic matter rich background soils, while the proximity to emission sources is reflected by BC–PAH association in urban soils.
اظهر المزيد [+] اقل [-]Bioaccessibility and health risk of arsenic, mercury and other metals in urban street dusts from a mega-city, Nanjing, China النص الكامل
2011
Hu, Xin | Zhang, Yun | Luo, Jun | Wang, Tijian | Lian, Hongzhen | Ding, Zhuhong
The oral bioaccessibility and the human health risks of As, Hg and other metals (Cu, Pb, Zn, Ni, Co, Cd, Cr, Mn, V and Fe) in urban street dusts from different land use districts in Nanjing (a mega-city), China were investigated. Both the total contents and the oral bioaccessibility estimated by the Simple Bioaccessibility Extraction Test (SBET) of the studied elements varied with street dusts from different land use districts. Cd, Zn, Mn, Pb, Hg and As showed high bioaccessibility. SBET-extractable contents of elements were significantly correlated with their total contents and the dust properties (pH, organic matter contents). The carcinogenic risk probability for As and Cr to children and adults were under the acceptable level (<1 × 10⁻⁴). Hazard Quotient values for single elements and Hazard Index values for all studied elements suggested potential non-carcinogenic health risk to children, but not to adults.
اظهر المزيد [+] اقل [-]Long-term patterns in soil acidification due to pollution in forests of the Eastern Sudetes Mountains النص الكامل
2011
Hédl, Radim | Petřík, Petr | Boublík, Karel
Soil acidification was assessed in the Eastern Sudetes Mountains (Czech Republic) between 1941 and 2003, i.e. before and after the period of major industrial pollution (1950s–1990s). The twenty sites included in our study were distributed along a gradient of altitude ranging 1000m. Values of pH have decreased in 80–90% of the pairs of samples after the six decades, on average by 0.7 for pH-H₂O and 0.6 for pH-KCl. Organic matter increased in the topsoil, probably reflecting a change in decomposition conditions. The most important finding is that the acidification varies along the joint gradient of altitude/tree layer composition, and displays a changing pattern in three soil horizons (A, B and C). Contrary to expectations, most acidified were soils in beech forests at lower elevations.
اظهر المزيد [+] اقل [-]Assessment of aided phytostabilization of copper-contaminated soil by X-ray absorption spectroscopy and chemical extractions النص الكامل
2011
Kumpiene, Jurate | Mench, Michel | Bes, Clémence M. | Fitts, Jeffrey P.
Assessment of aided phytostabilization of copper-contaminated soil by X-ray absorption spectroscopy and chemical extractions النص الكامل
2011
Kumpiene, Jurate | Mench, Michel | Bes, Clémence M. | Fitts, Jeffrey P.
Field plots were established at a timber treatment site to evaluate remediation of Cu contaminated topsoils with aided phytostabilization. Soil containing 2600mgkg⁻¹ Cu was amended with a combination of 5wt% compost and 2wt% iron grit, and vegetated. Sequential extraction was combined with extended X-ray absorption fine structure (EXAFS) spectroscopy to correlate changes in Cu distribution across five fractions with changes in the predominant Cu compounds two years after treatment in parallel treated and untreated field plots. Exchangeable Cu dominated untreated soil, most likely as Cu(II) species non-specifically bound to natural organic matter. The EXAFS spectroscopic results are consistent with the sequential extraction results, which show a major shift in Cu distribution as a result of soil treatment to the fraction bound to poorly crystalline Fe oxyhydroxides forming binuclear inner-sphere complexes.
اظهر المزيد [+] اقل [-]Assessment of aided phytostabilization of copper-contaminated soil by X-ray absorption spectroscopy and chemical extractions النص الكامل
2011
Kumpiene, Jurate | Mench, Michel | Bes, Clémence | Fitts, Jeffrey P. | Luleå University of Technology = Luleå Tekniska Universitet (LUT) | Biodiversité, Gènes & Communautés (BioGeCo) ; Institut National de la Recherche Agronomique (INRA)-Université de Bordeaux (UB) | Brookhaven National Laboratory [Upton, NY] (BNL) ; UT-Battelle, LLC-Stony Brook University [SUNY] (SBU) ; State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE)
International audience | Field plots were established at a timber treatment site to evaluate remediation of Cu contaminated topsoils with aided phytostabilization. Soil containing 2600 mg kg−1 Cu was amended with a combination of 5 wt% compost and 2 wt% iron grit, and vegetated. Sequential extraction was combined with extended X-ray absorption fine structure (EXAFS) spectroscopy to correlate changes in Cu distribution across five fractions with changes in the predominant Cu compounds two years after treatment in parallel treated and untreated field plots. Exchangeable Cu dominated untreated soil, most likely as Cu(II) species non-specifically bound to natural organic matter. The EXAFS spectroscopic results are consistent with the sequential extraction results, which show a major shift in Cu distribution as a result of soil treatment to the fraction bound to poorly crystalline Fe oxyhydroxides forming binuclear inner-sphere complexes.
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