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Zinc accumulation and synthesis of ZnO nanoparticles using Physalis alkekengi L
2011
Qu, Jiao | Yuan, Xing | Wang, Xinhong | Shao, Peng
A field survey and greenhouse experiments were conducted using Physalis alkekengi L. to investigate strategies of phytoremediation. In addition, ZnO nanoparticles were synthesized using P. alkekengi. P. alkekengi plants grew healthily at Zn levels from 50 to 5000mgkg⁻¹ in soils. The plants incorporated Zn into their aerial parts (with mean dry weight values of 235–10,980mgkg⁻¹) and accumulated biomass (with a mean dry weight of 25.7gplant⁻¹) during 12 weeks. The synthesized ZnO nanoparticles showed a polydisperse behavior and had a mean size of 72.5nm. The results indicate that P. alkekengi could be used for the remediation of zinc-contaminated soils. Moreover, the synthetic method of synthesizing ZnO nanoparticles from Zn hyperaccumulator plants constitutes a new insight into the recycling of metals in plant sources.
Show more [+] Less [-]The effect of nitrogen deposition on the species richness of acid grasslands in Denmark: A comparison with a study performed on a European scale
2011
Damgaard, Christian | Jensen, Lennarth | Frohn, Lise Marie | Borchsenius, F. (Finn) | Nielsen, Knud Erik | Ejrnæs, Rasmus | Stevens, Carly J.
The effect of atmospheric nitrogen deposition on the species richness of acid grasslands was investigated by combining data from a large Danish monitoring program with a large European data set, where a significant non-linear negative effect of nitrogen deposition had been demonstrated (Stevens et al., 2010). The nitrogen deposition range in Denmark is relatively small and when only considering the Danish data a non-significant decrease in the species richness with nitrogen deposition was observed. However, when both data sets were combined, then the conclusion of the European survey was further corroborated by the results of the Danish monitoring. Furthermore, by combining the two data sets a more comprehensive picture of the threats to the biodiversity of acid grasslands emerge; i.e., species richness in remnant patches of acid grassland in intensively cultivated agricultural landscapes is under influence not only from nitrogen deposition, but also from current and historical land use.
Show more [+] Less [-]Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats
2011
Stevens, Carly J. | Manning, Pete | van den Berg, Leon J.L. | de Graaf, Maaike C.C. | Wamelink, G.W Wieger | Boxman, Andries W. | Bleeker, Albert | Vergeer, Philippine | Arroniz-Crespo, Maria | Limpens, Juul | Lamers, Leon P.M. | Bobbink, Roland | Dorland, Edu
While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NHₓ and NOy) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversight requires attention. One reason for this knowledge gap is that plants experience a different NHₓ:NOy ratio in soil to that seen in atmospheric deposits because atmospheric inputs are modified by soil transformations, mediated by soil pH. Consequently species of neutral and alkaline habitats are less likely to encounter high NH₄ ⁺ concentrations than species from acid soils. We suggest that the response of vascular plant species to changing ratios of NHₓ:NOy deposits will be driven primarily by a combination of soil pH and nitrification rates. Testing this hypothesis requires a combination of experimental and survey work in a range of systems.
Show more [+] Less [-]Outdoor and indoor cadmium distributions near an abandoned smelting works and their relations to human exposure
2011
Spurgeon, David J. | Lawlor, Alan | Hooper, Helen L. | Wadsworth, Richard | Svendsen, Claus | Thomas, Laura D.K. | Ellis, James K. | Bundy, Jacob G. | Keun, Hector C. | Jarup, Lars
The relationship of measured or modelled Cd concentrations in soil, house dust and available to plants with human urinary Cd concentrations were assessed in a population living around a Cd/Pb/Zn smelter in the UK. Modelled air concentrations explained 35% of soil Cd variation indicating the smelter contributed to soil Cd loads. Multi-variate analysis confirmed a significant role of biological and life-style factors in determining urinary Cd levels. Significant correlations of urinary Cd with soil, house dust and modelled plant available Cd concentrations were not, however, found. Potential reasons for the absence of clear relationships include limited environmental contact in urban populations; the role of undefined factors in determining exposure; and the limited spatial scope of the survey which did not sample from the full pollution gradient. Further, the absence of any significant relationship indicates that environmental measures provide limited advantage over atmospheric model outputs for first stage human exposure assessment.
Show more [+] Less [-]Assessing seasonal and spatial trends of persistent organic pollutants (POPs) in Indian agricultural regions using PUF disk passive air samplers
2011
Pozo, Karla | Harner, Tom | Lee, Sum Chi | Sinha, Ravindra K. | Sengupta, B. | Loewen, Mark | Geethalakshmi, V. | Kannan, Kurunthachalam | Volpi, Valerio
The first survey of persistent organic pollutant (POP) concentrations in air across several Indian agricultural regions was conducted in 2006–2007. Passive samplers comprising polyurethane foam (PUF) disks were deployed on a quarterly basis at seven stations in agricultural regions, one urban site and one background site. The project was conducted as a sub-project of the Global Atmospheric Passive Sampling (GAPS) Network. In addition to revealing new information on air concentrations of several organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the study has demonstrated the feasibility of conducting regional-scale monitoring for POPs in India using PUF disk samplers. The following analytes were detected with relatively high concentrations in air (mean for 2006 and 2007, pg/m³): α- and γ-hexachlorocyclohexane (HCH) (292 and 812, respectively); endosulfan I and II (2770 and 902, respectively); p,p′-DDE and p,p′-DDT (247 and 931, respectively); and for the sum of 48 PCBs, 12,100 (including a site with extremely high air concentrations in 2007) and 972 (when excluding data for this site).
Show more [+] Less [-]2,4,6-Trinitrotoluene mineralization and bacterial production rates of natural microbial assemblages from coastal sediments
2011
Montgomery, Michael T. | Coffin, Richard B. | Boyd, Thomas J. | Smith, Joseph P. | Walker, Shelby E. | Osburn, Christopher L.
The nitrogenous energetic constituent, 2,4,6-Trinitrotoluene (TNT), is widely reported to be resistant to bacterial mineralization (conversion to CO₂); however, these studies primarily involve bacterial isolates from freshwater where bacterial production is typically limited by phosphorus. This study involved six surveys of coastal waters adjacent to three biome types: temperate broadleaf, northern coniferous, and tropical. Capacity to catabolize and mineralize TNT ring carbon to CO₂ was a common feature of natural sediment assemblages from these coastal environments (ranging to 270+/−38 μg C kg⁻¹ d⁻¹). More importantly, these mineralization rates comprised a significant proportion of total heterotrophic production. The finding that most natural assemblages surveyed from these ecosystems can mineralize TNT ring carbon to CO₂ is consistent with recent reports that assemblage components can incorporate TNT ring carbon into bacterial biomass. These data counter the widely held contention that TNT is recalcitrant to bacterial catabolism of the ring carbon in natural environments.
Show more [+] Less [-]Agricultural and green infrastructures: The role of non-urbanised areas for eco-sustainable planning in a metropolitan region
2011
La Greca, Paolo | La Rosa, Daniele | Martinico, Francesco | Privitera, Riccardo
Non-Urbanised Areas (NUAs) are part of agricultural and green infrastructures that provide ecosystem services. Their role is fundamental for the minimization of urban pollution and adaptation to climate change. Like all natural ecosystems, NUAs are endangered by urban sprawl. The regulation of sprawl is a key issue for land-use planning. We propose a land use suitability strategy model to orient Land Uses of NUAs, based on integration of Land Cover Analysis (LCA) and Fragmentation Analysis (FA). With LCA the percentage of evapotranspiring surface is defined for each land use. Dimensions and densities of NUAs patches are assessed in FA. The model has been developed with Geographical Information Systems, using an extensive set of geodatabases, including orthophotos, vectorial cartographies and field surveys. The case of the municipality of Mascalucia in Catania metropolitan area (Italy), characterized by a considerable urban sprawl, is presented.
Show more [+] Less [-]The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe
2011
Stevens, Carly J. | Duprè, Cecilia | Dorland, Edu | Gaudnik, Cassandre | Gowing, David J.G. | Bleeker, Albert | Diekmann, Martin | Alard, Didier | Bobbink, Roland | Fowler, David | Corcket, Emmanuel | Mountford, J Owen | Vandvik, Vigdis | Aarrestad, Per Arild | Muller, Serge | Dise, Nancy B.
A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2–44 kg N ha⁻¹ yr⁻¹) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate.
Show more [+] Less [-]Long-term environmental monitoring of persistent organic pollutants and metals in a chemical/petrochemical area: Human health risks
2011
Nadal, Martí | Schuhmacher, Marta | Domingo, José L.
Organic pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polycyclic aromatic hydrocarbons (PAHs), as well as some metals are periodically monitored in soil and vegetation samples collected in Tarragona County (Spain). We here report the temporal trends of the concentrations of the above pollutants between the initial survey (2002) and that recently (2009) performed. The area under evaluation was divided into 4 sections (chemical, petrochemical, urban/residential and unpolluted). In general terms, urban soils presented the highest concentrations of PCDD/Fs, PCNs and PAHs, confirming that traffic is a very important emission source of these pollutants. In addition, substantially higher levels of PAHs and some metals were found in vegetation samples from the petrochemical complex. The assessment of health risks of these contaminants indicated that the current concentrations of micropollutants did not mean additional non-carcinogenic or cancer risks for the population living in the zone.
Show more [+] Less [-]Open Air Laboratories (OPAL): A community-driven research programme
2011
Davies, L. | Bell, J.N.B. | Bone, J. | Creagh-Henry, M. (May) | Hill, L. | Howard, C. | Hobbs, S.J. | Jones, D.T. | Power, S.A. | Rose, N. | Ryder, C. | Seed, L. | Stevens, G. | Toumi, R. | Voulvoulis, N. | White, P.C.L.
OPAL is an English national programme that takes scientists into the community to investigate environmental issues. Biological monitoring plays a pivotal role covering topics of: i) soil and earthworms; ii) air, lichens and tar spot on sycamore; iii) water and aquatic invertebrates; iv) biodiversity and hedgerows; v) climate, clouds and thermal comfort. Each survey has been developed by an inter-disciplinary team and tested by voluntary, statutory and community sectors. Data are submitted via the web and instantly mapped. Preliminary results are presented, together with a discussion on data quality and uncertainty. Communities also investigate local pollution issues, ranging from nitrogen deposition on heathlands to traffic emissions on roadside vegetation. Over 200,000 people have participated so far, including over 1000 schools and 1000 voluntary groups. Benefits include a substantial, growing database on biodiversity and habitat condition, much from previously unsampled sites particularly in urban areas, and a more engaged public.
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