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Release of native and mass labelled PCDD/PCDF from soil heated to simulate bushfires
2012
Black, Robert R. | Meyer, Carl P. | Yates, Alan | Zwieten, Lukas van | Chittim, Brock G. | Gaus, Caroline | Mueller, Jochen F.
Soil is an important reservoir of PCDD/PCDF, which can be released when environmental conditions change. Fire is an extreme event that can increase the surface temperatures of soil substantially, yet little is known of the role soil plays in the emission of PCDD/PCDF. Soil containing native PCDD/PCDF was fortified with a mixture of mass labelled PCDD/PCDF and heated between 150°C and 400°C. Both native and mass labelled PCDD/PCDF were released from the soil beyond 200°C. Release of the mass labelled compounds was linearly related to temperature with up to 9 % found in the air stream at 400°C. The release of some native PCDD/PCDF was much greater. At 400°C, emission of 1,2,3,7,8-Cl₅DD was 300% compared to pre-experimental soil. Emission of PCDD/PCDF from soil during bushfires is a relevant process and may originate from both volatilization and formation via de novo or precursor pathways, or dechlorination.
Показать больше [+] Меньше [-]Synthetic fertilizer management for China’s cereal crops has reduced N₂O emissions since the early 2000s
2012
Sun, Wenjuan | Huang, Yao
China has implemented a soil testing and fertilizer recommendation (STFR) program to reduce the over-usage of synthetic nitrogen (N) fertilizer on cereal crops since the late 1990s. Using province scale datasets, we estimated an annual reduction rate of 2.5–5.1 kg N ha⁻¹ from 1998 to 2008 and improving grain yields, which were attributed to the balanced application of phosphate and potassium fertilization. Relative to the means for 1998–2000, the synthetic N fertilizer input and the corresponding N-induced N₂O production in cereal crops were reduced by 22 ± 0.7 Tg N and 241 ± 4 Gg N₂O–N in 2001–2008. Further investigation suggested that the N₂O emission related to wheat and maize cultivation could be reduced by 32–43 Gg N₂O–N per year in China (26%–41% of the emissions in 2008) if the STFR practice is implemented universally in the future.
Показать больше [+] Меньше [-]Arsenic fractionation in mine spoils 10 years after aided phytostabilization
2012
Kumpiene, Jurate | Fitts, Jeffrey P. | Mench, Michel
Aided phytostabilization using a combination of compost, zerovalent iron grit and coal fly ash (CZA) amendments and revegetation effectively promoted the biological recovery of mining spoils generated at a gold mine in Portugal. Selective dissolution of spoil samples in combination with solid phase characterization using microbeam X-ray absorption near edge structure (μXANES) spectroscopy and microbeam X-ray fluorescence (μXRF) mapping were used to assess As associations in spoils ten years after CZA treatment. The results show that As preferentially associates with poorly crystalline Fe-oxyhydroxides as opposed to crystalline Fe-(oxyhydr)oxide phases. The crystalline Fe(III)-phases dominated in the treated spoil and exceeded those of the untreated spoil three-fold, but only 2.6–6.8% of total As was associated with this fraction. Correlation maps of As:Fe reveal that As in the CZA-treated spoils is primarily contained in surface coatings as precipitates and sorbates. Arsenic binding with poorly crystalline Fe-oxyhydroxides did not inhibit As uptake by plants.
Показать больше [+] Меньше [-]Development of aquatic life criteria for nitrobenzene in China
2012
Yan, Zhen-guang | Cheung, Chi Sing | Wang, Hong | Liang, Feng | Li, Ji | Liu, Hong-ling | Sun, Cheng | Liang, Li-jun | Liu, Zheng-tao
Nitrobenzene is a toxic pollutant and was the main compound involved in the Songhuajiang accident in 2007, one of the largest water pollution accidents in China in the last decade. No aquatic life criteria for nitrobenzene have previously been proposed. In this study, published toxicity data of nitrobenzene to Chinese aquatic species were gathered, and six resident Chinese aquatic organisms were used in toxicity tests to supplement the existing toxicity data for nitrobenzene. Seventeen genuses mean acute values, three genuses mean chronic values to freshwater aquatic animals, and six genus toxicity values to aquatic plants were collected in total. A criterion maximum concentration of 0.018mg/L and a criterion continuous concentration of 0.001mg/L were developed based on these data, according to the U.S. Environmental Protection Agency guidelines. These criteria may be useful in the determination of water quality standard of nitrobenzene.
Показать больше [+] Меньше [-]Lead phytotoxicity in soils and nutrient solutions is related to lead induced phosphorus deficiency
2012
Cheyns, Karlien | Peeters, Sofie | Delcourt, Dorien | Smolders, Erik
This study was set up to relate lead (Pb) bioavailability with its toxicity to plants in soils. Tomato and barley seedlings were grown in six different PbCl₂ spiked soils (pH: 4.7–7.4; eCEC: 4.2–41.7 cmolc/kg). Soils were leached and pH corrected after spiking to exclude confounding factors. Plant growth was halved at 1600–6500 mg Pb/kg soil for tomato and at 1900–8300 mg Pb/kg soil for barley. These soil Pb threshold were unrelated to soil pH, organic carbon, texture or eCEC and neither soil solution Pb nor Pb²⁺ ion activity adequately explained Pb toxicity among soils. Shoot phosphorus (P) concentrations significantly decreased with increasing soil Pb concentrations. Tomato grown in hydroponics at either varying P supply or at increasing Pb (equal initial P) illustrated that shoot P explained growth response in both scenarios. The results suggest that Pb toxicity is partially related to Pb induced P deficiency, likely due to lead phosphate precipitation.
Показать больше [+] Меньше [-]Ozone pollution affects flower numbers and timing in a simulated BAP priority calcareous grassland community
2012
Hayes, Felicity | Williamson, Jennifer | Mills, Gina
Mesocosms representing the BAP Priority habitat ‘Calcareous Grassland’ were exposed to eight ozone profiles for twelve-weeks in two consecutive years. Half of the mesocosms received a reduced watering regime during the exposure periods. Numbers and timing of flowering in the second exposure period were related to ozone concentration and phytotoxic ozone dose (accumulated stomatal flux). For Lotus corniculatus, ozone accelerated the timing of the maximum number of flowers. An increase in mean ozone concentration from 30ppb to 70ppb corresponded with an advance in the timing of maximum flowering by six days. A significant reduction in flower numbers with increasing ozone was found for Campanula rotundifolia and Scabiosa columbaria and the relationship with ozone was stronger for those that were well-watered than for those with reduced watering. These changes in flowering timing and numbers could have large ecological impacts, affecting plant pollination and the food supply of nectar feeding insects.
Показать больше [+] Меньше [-]Enhancement of life cycle assessment (LCA) methodology to include the effect of surface albedo on climate change: Comparing black and white roofs
2012
Susca, Tiziana
Traditionally, life cycle assessment (LCA) does not estimate a key property: surface albedo. Here an enhancement of the LCA methodology has been proposed through the development and employment of a time-dependent climatological model for including the effect of surface albedo on climate. The theoretical findings derived by the time-dependent model have been applied to the case study of a black and a white roof evaluated in the time-frames of 50 and 100 years focusing on the impact on global warming potential. The comparative life cycle impact assessment of the two roofs shows that the high surface albedo plays a crucial role in offsetting radiative forcings. In the 50-year time horizon, surface albedo is responsible for a decrease in CO₂eq of 110–184 kg and 131–217 kg in 100 years. Furthermore, the white roof compared to the black roof, due to the high albedo, decreases the annual energy use of about 3.6–4.5 kWh/m².
Показать больше [+] Меньше [-]Mercury contamination in the Laurentian Great Lakes region: Introduction and overview
2012
Wiener, James G. | Evers, David C. | Gay, David A. | Morrison, Heather A. | Williams, Kathryn A.
The Laurentian Great Lakes region of North America contains substantial aquatic resources and mercury-contaminated landscapes, fish, and wildlife. This special issue emanated from a bi-national synthesis of data from monitoring programs and case studies of mercury in the region, here defined as including the Great Lakes, the eight U.S. states bordering the Great Lakes, the province of Ontario, and Lake Champlain. We provide a retrospective overview of the regional mercury problem and summarize new findings from the synthesis papers and case studies that follow. Papers in this issue examine the chronology of mercury accumulation in lakes, the importance of wet and dry atmospheric deposition and evasion to regional mercury budgets, the influence of land–water linkages on mercury contamination of surface waters, the bioaccumulation of methylmercury in aquatic foods webs; and ecological and health risks associated with methylmercury in a regionally important prey fish.
Показать больше [+] Меньше [-]Estimating mercury concentrations and fluxes in the water column and sediment of Lake Ontario with HERMES model
2012
Ethier, Adrienne L.M. | Atkinson, Joseph F. | DePinto, Joseph V. | Lean, David R.S.
The HERMES model-predicted Hg concentrations and fluxes in Lake Ontario were based on twelve lake and drainage basin variables (i.e., water temperature, precipitation rate, air Hg, surface area, mean depth, water volume, water inflow rate, inflow water Hg, inflow and lake suspended particulate matter, air–water and water–air mass transfer coefficients, and sedimentation rate). The HERMES model-predicted Hg water and surface sediment concentrations were found to be significantly correlated (±20%) with measured values (r² = 0.94, p < 0.0001, n = 13) and mechanistic model predictions (LOTOX2-Hg, r² = 0.95, p < 0.0001, n = 10). The predictive capacity of HERMES was previously tested on smaller (≤1 km²) lakes in Nova Scotia and Ontario, Canada (i.e., water and sediment Hg concentrations were ±15% of measured data). Results suggest that HERMES could be applicable to a broad range of lake sizes. Uncertainty analyses on HERMES model input variables indicated a larger atmospheric Hg contribution for Lake Ontario when compared to previous predictions for smaller lakes.
Показать больше [+] Меньше [-]Abundance of birds in Fukushima as judged from Chernobyl
2012
Møller, A. P. (Anders Pape) | Hagiwara, A. (Atsushi) | Matsui, Shin | Kasahara, Satoe | Kawatsu, Kencho | Nishiumi, Isao | Suzuki, Hiroyuki | Ueda, Keisuke | Mousseau, Timothy A.
The effects of radiation on abundance of common birds in Fukushima can be assessed from the effects of radiation in Chernobyl. Abundance of birds was negatively related to radiation, with a significant difference between Fukushima and Chernobyl. Analysis of 14 species common to the two areas revealed a negative effect of radiation on abundance, differing between areas and species. The relationship between abundance and radiation was more strongly negative in Fukushima than in Chernobyl for the same 14 species, demonstrating a negative consequence of radiation for birds immediately after the accident on 11 March 2011 during the main breeding season in March–July, when individuals work close to their maximum sustainable level.
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