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981.
Keenan PO Knight AW Billinton N Cahill PA Dalrymple IM Hawkyard CJ Stratton-Campbell D Walmsley RM 《Journal of environmental monitoring : JEM》2007,9(12):1394-1401
Discharges of coloured effluents into surface waters provide conspicuous evidence of the impact of industry on the environment. The textile industry is an obvious candidate for sources of such discharges. Conventional treatment methods appear to alleviate this situation by removing colour, however the affect on toxicity is less obvious. The objective of this study was to examine the changes in effluent toxicity during the course of two alternative wastewater treatment methods, ozonation and electrochemical oxidation, using a novel toxicity biosensor, GreenScreen EM. The biosensor is capable of measuring both general acute toxicity (cytotoxicity), and more specifically genotoxicity, that is damage to a cell's DNA structure, replication or distribution, caused by substances that may be mutagenic and/or carcinogenic. The biosensor utilises a modified strain of the brewers yeast Saccharomyces cerevisiae, incorporating a gene encoding green fluorescent protein (GFP) linked to the inducible promoter of the DNA damage responsive RAD54 gene. Upon exposure to a genotoxin, the production of GFP is up-regulated in parallel with RAD54, and the resulting cellular fluorescence provides a measure of genotoxicity. Acute toxicity is simultaneously determined by monitoring relative total growth of the cell culture during incubation. The results presented in this paper show that a reduction in colouration does not necessarily correspond to a reduction in effluent toxicity. 相似文献
982.
Impediments to recovery in New Orleans' Upper and Lower Ninth Ward: one year after Hurricane Katrina 总被引:1,自引:0,他引:1
In the aftermath of Hurricane Katrina, a rapid succession of plans put forward a host of recovery options for the Upper and Lower Ninth Ward in New Orleans. Much of the debate focused on catastrophic damage to residential structures and discussions of the capacity of low-income residents to repair their neighbourhoods. This article examines impediments to the current recovery process of the Upper and Lower Ninth Ward, reporting results of an October 2006 survey of 3,211 plots for structural damage, flood damage and post-storm recovery. By examining recovery one year after Hurricane Katrina, and by doing so in the light of flood and structural damage, it is possible to identify impediments to recovery that may disproportionately affect these neighbourhoods. This paper concludes with a discussion of how pre- and post-disaster inequalities have slowed recovery in the Lower Ninth Ward and of the implications this has for post-disaster recovery planning there and elsewhere. 相似文献
983.
Valve and cardiac activity were simultaneously measured in the blue mussel (Mytilus edulis) in response to 10?d copper exposure. Valve movements, heart rates and heart-rate variability were obtained non-invasively using a Musselmonitor® (valve activity) and a modified version of the Computer-Aided Physiological Monitoring system (CAPMON; cardiac activity). After 2?d exposure of mussels (4 individuals per treatment group) to a range of dissolved copper concentrations (0 to 12.5?M as CuCl2) median valve positions (% open) and median heart rates (beats per minute) declined as a function of copper concentration. Heart-rate variability (coefficient of variation for interpulse durations) rose in a concentration-dependent manner. The 48?h EC50 values (concentrations of copper causing 50% change) for valve positions, heart rates and heart-rate variability were 2.1, 0.8, and 0.06?M, respectively. Valve activity was weakly correlated with both heart rate (r?=?0.48?±?0.02) and heart-rate variability (r?=?0.32?±?0.06) for control individuals (0?M Cu2+). This resulted from a number of short enclosure events that did not coincide with a change in cardiac activity. Exposure of mussels to increasing copper concentrations (≥0.8?M) progressively reduced the correlation between valve activity and heart rates (r?=?0 for individuals dosed with ≥6.3?M Cu2+), while correlations between valve activity and heart-rate variability were unaffected. The poor correlations resulted from periods of valve flapping that were not mimicked by similar fluctuations in heart rate or heart-rate variability. The data suggest that the copper-induced bradycardia observed in mussels is not a consequence of prolonged valve closure. 相似文献
984.
Conflicts over how to “scale” policy-making tasks have characterized environmental governance since time immemorial. They
are particularly evident in the area of water policy and raise important questions over the democratic legitimacy, economic
efficiency and effectiveness of allocating (or “scaling”) tasks to some administrative levels as opposed to others. This article
adopts a comparative federalism perspective to assess the “optimality” of scaling—either upward or downward—in one issue area,
namely coastal recreational water quality. It does so by comparing the scaling of recreational water quality tasks in the
European Union (EU) and Australia. It reveals that the two systems have adopted rather different approaches to scaling and
that this difference can partly be accounted for in federal theoretical terms. However, a much greater awareness of the inescapably
political nature of scaling processes is nonetheless required. Finally, some words of caution are offered with regard to transferring
policy lessons between these two jurisdictions. 相似文献
985.
Andrew J. McElrone Jason G. Hamilton Mihai Aldea Evan H. DeLucia 《Environmental pollution (Barking, Essex : 1987)》2010,158(1):108-114
Atmospheric CO2 concentrations are predicted to double within the next century and alter climate regimes, yet the extent that these changes will affect plant diseases remains unclear. In this study conducted over five years, we assessed how elevated CO2 and interannual climatic variability affect Cercospora leaf spot diseases of two deciduous trees. Climatic data varied considerably between the five years and altered disease expression. Disease incidence and severity for both species were greater in years with above average rainfall. In years with above average temperatures, disease incidence for Liquidambar styraciflua was decreased significantly. When significant changes did occur, disease incidence and severity always increased under elevated CO2. Chlorophyll fluorescence imaging of leaves revealed that any visible increase in disease severity induced by elevated CO2 was mitigated by higher photosynthetic efficiency in the remaining undamaged leaf tissue and in a halo surrounding lesions. 相似文献
986.
Ajay K. Manna Andrew R. Martin 《Environmental pollution (Barking, Essex : 1987)》2010,158(3):805-1394
Experimental investigations were carried out on removal of arsenic from contaminated groundwater by employing a new flat-sheet cross flow membrane module fitted with a hydrophobic polyvinylidenefluoride (PVDF) microfiltration membrane. The new design of the solar-driven membrane module in direct contact membrane distillation (DCMD) configuration successfully produced almost 100 per cent arsenic-free water from contaminated groundwater in a largely fouling-free operation while permitting high fluxes under reduced temperature polarization. For a feed flow rate of 0.120 m3/h, the 0.13 μm PVDF membrane yielded a high flux of 74 kg/(m2 h) at a feed water temperature of 40 °C and, 95 kg/m2 h at a feed water temperature of 60 °C. The encouraging results show that the design could be effectively exploited in the vast arsenic-affected rural areas of South-East Asian countries blessed with abundant sunlight particularly during the critical dry season. 相似文献
987.
Vladimir Novotny Xiaoyan Wang Andrew J. EnglandeJr. David Bedoya Luksamee Promakasikorn Reyes Tirado 《Environment, Development and Sustainability》2010,12(4):491-509
This article describes a study of the environmental impacts of the use of industrial agricultural chemicals in four Asian
countries—China, India, the Philippines and Thailand. The objective was to contribute objectively to the discussion on the
extent of the problem, past and current damages to the environment to and outline possible paths to sustainable and environmentally
benign agriculture. The four countries are experiencing rapid economic growth under a tremendous population growth pressure
that, with the exception of China, will continue without leveling of in a foreseeable future. This requires more food production
that has been accomplished by the increased use of industrial chemical fertilizers. Although the four countries uses of industrial
chemicals vary, the mix of nutrients appears to be imbalanced, resulting in large nitrogen losses into the environment, especially
in China. A suggested solution of the problem begins with reducing (China) or maintaining (India, the Philippines, Thailand)
average nutrient application levels needed by the crops and includes optimal hybrid agriculture by using organic fertilizers,
and fertilizers in the irrigation water already overloaded with nitrogen. There is a need to balance fertilizer N and P applications
with the crop needs. 相似文献
988.
Tire wear particles filed from the treads of end-of-life vehicle tires have been added to sea water to examine the release of Zn and the toxicity of the resulting leachate and dilutions thereof to the marine macroalga, Ulva lactuca. Zinc release appeared to be diffusion-controlled, with a conditional rate constant of 5.4 μg[L(h)1/2]−1, and about 1.6% of total Zn was released after 120 h incubation. Exposure to increasing concentrations of leachate resulted in a non-linear reduction in the efficiency of photochemical energy conversion of U. lactuca and, with the exception of the undiluted leachate, increasing accumulation of Zn. Phototoxicity was significantly lower on exposure to equivalent concentrations of Zn added as Zn(NO3)2, suggesting that organic components of leachate are largely responsible for the overall toxicity to the alga. Given the ubiquity and abundance of TWP in urban coastal sediments, the generation, biogeochemistry and toxicity of tire leachate in the marine setting merit further attention. 相似文献
989.
Margaret J. Sobkowicz John R. Dorgan Keith W. Gneshin Andrew M. Herring J. Thomas McKinnon 《Journal of Polymers and the Environment》2008,16(2):131-140
Nucleation of polylactide and polypropylene using novel renewable resource biobased carbon nanospheres (CNS) is investigated
using differential scanning calorimetry and polarized optical microscopy. Isothermal studies near the optimal crystallization
temperature demonstrate at least a five-fold increase in crystallization rate in PP but only a 1.4 times faster crystallization
in PLA. Non-isothermal studies reveal an asymptotic relationship of the maximum crystallization temperature with increasing
CNS weight loading in PP and no relationship in PLA. Microscopy indicates some aggregation in the solution blended samples
and that average spherulite size is reduced 10-fold due to faster nucleation in the composites as compared to the neat polymer.
The fractional crystallinity achieved during non-isothermal crystallization increases by about 7% with addition of a small
amount of CNS and decreases with weight loading higher than 1%. The crystallization rates obtained in polypropylene are competitive
with widely used mineral talc nucleating agents. 相似文献
990.
Jim E. Szecsody James P. McKinley Andrew T. Breshears Fiona H. Crocker 《补救:环境净化治理成本、技术与工艺杂志》2008,19(1):109-123
The N‐nitrosodimethylamine (NDMA) degradation rate and mineralization rate were measured in two aquifer sediments that received treatments to create oxic, reducing, and sequential reducing/oxic environments. Chemically reduced sediments rapidly abiotically degraded NDMA to nontoxic dimethylamine to parts per trillion levels, then degraded to further products. NDMA was partially mineralized in reduced sediments (6 to 28 percent) at a slow rate (half‐life 3,460 h) by an unknown abiotic/biotic pathway. In contrast, NDMA was mineralized more rapidly (half‐life 342 h) and to a greater extent (30 to 81 percent) in oxic sediments with propane addition, likely by a propane monooxygenase pathway. NDMA mineralization in sequential reduced sediment followed by oxic sediment treatment did result in slightly more rapid mineralization and a greater mineralization extent relative to reduced systems. These increases were minor, so aerobic NDMA mineralization with oxygen and propane addition was the most viable in situ NDMA mineralization strategy. © 2008 Wiley Periodicals, Inc. 相似文献