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Impacts of urbanization on carbon balance in terrestrial ecosystems of the Southern United States Полный текст
2012
Zhang, Chi | Tian, Hanqin | Chen, Guangsheng | Chappelka, Arthur | Xu, Xiaofeng | Ren, Wei | Hui, Dafeng | Liu, Mingliang | Lu, Chaoqun | Pan, Shufen | Lockaby, Graeme
Using a process-based Dynamic Land Ecosystem Model, we assessed carbon dynamics of urbanized/developed lands in the Southern United States during 1945–2007. The results indicated that approximately 1.72 (1.69–1.77) Pg (1P = 10¹⁵) carbon was stored in urban/developed lands, comparable to the storage of shrubland or cropland in the region. Urbanization resulted in a release of 0.21 Pg carbon to the atmosphere during 1945–2007. Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. After a rapid decline of carbon storage during land conversion, an urban ecosystem gradually accumulates carbon and may compensate for the initial carbon loss in 70–100 years. The carbon sequestration rate of urban ecosystem diminishes with time, nearly disappearing in two centuries after land conversion. This study implied that it is important to take urbanization effect into account for assessing regional carbon balance.
Показать больше [+] Меньше [-]Indicating atmospheric sulfur by means of S-isotope in leaves of the plane, osmanthus and camphor trees Полный текст
2012
Xiao, Hua-Yun | Wang, Yan-Li | Tang, Cong-Guo | Liu, Cong-Qiang
Foliar δ³⁴S values of three soil-growing plant species (Platanus Orientalis L., Osmanthus fragrans L. and Cinnamomum camphora) have been analyzed to indicate atmospheric sulfur. The foliar δ³⁴S values of the three plant species averaged −3.11±1.94‰, similar to those of both soil sulfur (−3.73±1.04‰) and rainwater sulfate (−3.07±2.74‰). This may indicate that little isotopic fractionation had taken place in the process of sulfur uptake by root or leaves. The δ³⁴S values changed little in the transition from mature leaves to old/senescing leaves for both the plane tree and the osmanthus tree, suggestive of little isotope effect during sulfur redistribution in plant tissues. Significantly linear correlation between δ³⁴S values of leaves and rainwater sulfate for the plane and osmanthus trees allowed the tracing of temporal variations of atmospheric sulfur by means of foliar sulfur isotope, while foliage δ³⁴S values of the camphor is not an effective indicator of atmospheric sulfur.
Показать больше [+] Меньше [-]Composting of waste paint sludge containing melamine resin as affected by nutrients and gypsum addition and microbial inoculation Полный текст
2012
Tian, Yongqiang | Chen, Liming | Gao, Lihong | Michel, Frederick C., Jr | Wan, Caixia | Li, Yebo | Dick, Warren A.
Melamine formaldehyde resins have hard and durable properties and are found in many products, including automobile paints. These resins contain high concentrations of nitrogen and, if properly composted, can yield valuable products. We evaluated the effects of starter compost, nutrients, gypsum and microbial inoculation on composting of paint sludge containing melamine resin. A bench-scale composting experiment was conducted at 55 °C for 91 days and then at 30 °C for an additional 56 days. After 91 days, the composts were inoculated with a mixed population of melamine-degrading microorganisms. Melamine resin degradation after the entire 147 days of composting varied between 73 and 95% for the treatments with inoculation of microorganisms compared to 55–74% for the treatments without inoculation. Degradation was also enhanced by nutrients and gypsum additions. Our results infer that large scale composting of melamine resins in paint sludge is possible.
Показать больше [+] Меньше [-]Cosorption of organic chemicals with different properties: Their shared and different sorption sites Полный текст
2012
Zhang, Di | Pan, Bo | Wu, Min | Zhang, Huang | Peng, Hongbo | Ning, Ping | Xing, Baoshan
Complementary sorption of different chemicals was expected and investigating the relationship between the sorption inhibition of primary sorbate (ΔQᵖʳⁱ) and sorption of secondary sorbate (Qˢᵉᶜ) could provide a new angle to understand coadsorption of different chemicals. This study used bisphenol A (BPA) as the primary adsorbate, sulfamethoxazole (SMX) as the competitor, and carbon nanotubes as model adsorbents to study their complementary and competitive adsorption. At low BPA concentrations, the sorption of SMX (Qˢᵉᶜ) exceeded BPA sorption inhibition (ΔQᵖʳⁱ), indicating that these two chemicals complementarily adsorbed on their respectively preferred sorption sites. At high BPA concentrations, higher ΔQᵖʳⁱ was observed in comparison to Qˢᵉᶜ, which may be resulted from different packing efficiencies of the adsorbed SMX and BPA. This study emphasized that both competitive and complementary sorption should be discussed in binary sorption system.
Показать больше [+] Меньше [-]Quality of roof-harvested rainwater – Comparison of different roofing materials Полный текст
2012
Lee, Ju Young | Bak, Gippeum | Han, Mooyoung
The objective of the study reported in this paper was to assess the quality of harvested rainwater on the basis of the roofing materials used and the presence of lichens/mosses on the roofing surface. Four pilot structures with different roofing materials (i.e., wooden shingle tiles, concrete tiles, clay tiles [Gi-Wa] and galvanized steel) were installed in a field. The galvanized steel was found to be the most suitable for rainwater harvesting applications, with their resulting physical and chemical water quality parameters meeting the Korean guidelines for drinking water quality (e.g., pH (5.8–8.5), TSS <500 mg/L, NO₃ ⁻ < 10 mg/L, SO₄ ²⁻ < 200 mg/L, Al < 0.2 mg/L, Cu < 1 mg/L, Fe < 0.3 mg/L, Pb < 0.05 mg/L, Zn < 1 mg/L, and E. coli (No detection)). In the galvanized steel case, the relatively high water quality was probably due to ultraviolet light and the high temperature effectively disinfecting the harvested rainwater. It was also found that the presence of lichens and mosses may adversely affect the physical, chemical and microbiological quality of rainwater.
Показать больше [+] Меньше [-]Environmental policy, legislation and management of persistent organic pollutants (POPs) in China Полный текст
2012
Lau, Melody Hoi Yin | Leung, Kenneth Mei Yee | Wong, Stella Wing Yu | Wang, Hong | Yan, Zhen-Guang
Since early 1980s, chemical pollution has become a serious environmental problem in rapidly developing China. This study reviewed the policy and legal framework for monitoring and management of chemical pollutants in China, with reference to the relevant experience in other jurisdictions. Although efforts in environmental monitoring of chemical contamination have been substantially increased over the last decade, China is lagging behind in terms of nationwide monitoring of chemical contamination in human population, and standardization of sampling and analytical protocols. While actively participating in various international treaties and conventions related to pollution control, China also has a very comprehensive set of environmental laws and policies. These include the newly enacted legislation on the control of new chemicals (i.e., China REACH) and the development of a set of National Environmental Standards. In addition to environmental education, these new measures will further enhance the control of chemical pollutants and facilitate effective law enforcement.
Показать больше [+] Меньше [-]Mutagenicity assessment of aerosols in emissions from wood combustion in Portugal Полный текст
2012
Vu, B. | Alves, C.A. | Gonçalves, C. | Pio, C. | Gonçalves, F. | Pereira, R.
Mutagenicity assessment of aerosols in emissions from wood combustion in Portugal Полный текст
2012
Vu, B. | Alves, C.A. | Gonçalves, C. | Pio, C. | Gonçalves, F. | Pereira, R.
Polycyclic aromatic hydrocarbon (PAH) extracts of fine particles (PM₂.₅) collected from combustion of seven wood species and briquettes were tested for mutagenic activities using Ames test with Salmonella typhimurium TA98 and TA100. The woods were Pinus pinaster (maritime pine), Eucalyptus globulus (eucalypt), Quercus suber (cork oak), Acacia longifolia (golden wattle), Quercus faginea (Portuguese oak), Olea europea (olive), and Quercus ilex rotundifolia (Holm oak). Burning experiments were done using woodstove and fireplace, hot start and cold start conditions. A mutagenic response was recorded for all species except golden wattle, maritime pine, and briquettes. The mutagenic extracts were not correlated with high emission factors of carcinogenic PAHs. These extracts were obtained both from two burning appliances and start-up conditions. However, fireplace seemed to favour the occurrence of mutagenic emissions. The negative result recorded for golden wattle was interesting, in an ecological point of view, since after confirmation, this invasive species, can be recommended for domestic use.
Показать больше [+] Меньше [-]Mutagenicity assessment of aerosols in emissions from wood combustion in Portugal Полный текст
2012
Vu, B. | Alves, C. A. | Gonçalves, C. | Pio, C. | Gonçalves, F. | Pereira, R.
Polycyclic aromatic hydrocarbon (PAH) extracts of fine particles (PM(2.5)) collected from combustion of seven wood species and briquettes were tested for mutagenic activities using Ames test with Salmonella typhimurium TA98 and TA100. The woods were Pinus pinaster (maritime pine), Eucalyptus globulus (eucalypt), Quercus suber (cork oak), Acacia longifolia (golden wattle), Quercus faginea (Portuguese oak), Olea europea (olive), and Quercus ilex rotundifolia (Holm oak). Burning experiments were done using woodstove and fireplace, hot start and cold start conditions. A mutagenic response was recorded for all species except golden wattle, maritime pine, and briquettes. The mutagenic extracts were not correlated with high emission factors of carcinogenic PAHs. These extracts were obtained both from two burning appliances and start-up conditions. However, fireplace seemed to favour the occurrence of mutagenic emissions. The negative result recorded for golden wattle was interesting, in an ecological point of view, since after confirmation, this invasive species, can be recommended for domestic use. | published
Показать больше [+] Меньше [-]Effects of aging on the digestive solubilization of Cu from sediments Полный текст
2012
Zhong, Huan | Kraemer, Lisa | Evans, Douglas
Solubilization of particulate Cu by different solutions, mimicking digestive fluids of deposit-feeders, was quantified in stable isotope ⁶⁵Cu-spiked sediments (with 3 days-2 months Cu-sediment contact time or aging). Copper solubilization generally decreased with prolonged aging. However, such decrease became less evident after 1 month and equilibrium of Cu in sediments could be reached after 2 months. Aging effects on Cu solubilization can be explained by the changes in Cu geochemical fractionation with aging: Cu generally transferred from more mobile phases (carbonate and Fe–Mn associated) to more refractory phases (organic associated and residual phase). Besides Cu geochemical fractionation, digestive fluid composition and different Cu solubilization pathways involved, as well as sedimentary organic content, could all affect the digestive solubilization of Cu and its change with aging. Our results emphasize the necessity of considering Cu aging in laboratory sediment toxicity experiments, and in risk assessment of Cu contaminated sediments.
Показать больше [+] Меньше [-]Impact of atmospheric deposition of As, Cd and Pb on their concentration in carrot and celeriac Полный текст
2012
De Temmerman, Ludwig | Ruttens, Ann | Waegeneers, Nadia
Root crops, carrot and celeriac, were exposed to atmospheric deposition in a polluted versus reference area. An effect was observed on the As, Cd and Pb concentrations of the leaves and the storage organs. The concentrations in the whole storage organs correlated well with atmospheric deposition, which shows that they even could be used for biomonitoring. Nevertheless, leaves remain much more appropriate. The results revealed also a significant increase of the As and Cd concentration in the consumable part of the storage organs as a function of their atmospheric deposition. As such the experiments allowed deriving regression equations, useful for modeling the atmospheric impact of trace elements on the edible parts of root crops. For Pb, however, there was hardly any significant impact on the inner parts of the storage organs and as such the transfer of Pb in the food chain through root crops can be considered to be negligible.
Показать больше [+] Меньше [-]Effects of high CO₂ concentrations on ecophysiologically different microorganisms Полный текст
2012
Schulz, Alexandra | Vogt, Carsten | Richnow, Hans-Hermann
We investigated the effect of increasing CO₂ concentrations on the growth and viability of ecophysiologically different microorganisms to obtain information for a leakage scenario of CO₂ into shallow aquifers related to the capture and storage of CO₂ in deep geological sections. CO₂ concentrations in the gas phase varied between atmospheric conditions and 80% CO₂ for the aerobic strains Pseudomonas putida F1 and Bacillus subtilis 168 and up to 100% CO₂ for the anaerobic strains Thauera aromatica K172 and Desulfovibrio vulgaris Hildenborough. Increased CO₂ concentrations caused prolonged lag-phases, and reduced growth rates and cell yields; the extent of this effect was proportional to the CO₂ concentration. Additional experiments with increasing CO₂ concentrations and increasing pressure (1–5000 kPa) simulated situations occurring in deep CO₂ storage sites. Living cell numbers decreased significantly within 24 h at pressures ≥1000 kPa, demonstrating a severe lethal effect for the combination of high pressure and CO₂.
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