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541.
Elodea canadensis has been proposed as a potential biomonitor due to its wide distribution and apparent ability to accumulate pollutants in aquatic ecosystems. We investigated the effects of copper sulfate on growth in E. canadensis to determine its effectiveness as a biomonitor of copper pollution in aquatic systems and whether growth is a suitable index of sub-lethal stress. Copper sulfate significantly slowed or stopped growth at all concentrations (low: 1 ppm, medium: 5 ppm, high: 10 ppm of copper sulfate) used. Final plant drymass was significantly lower in medium and high copper treatments compared with controls. E. canadensis appears to be very sensitive to copper levels, and may be useful as a biomonitor of copper levels in aquatic systems. However, its utility as a bioaccumulator may be limited, because we observed senescence of most leaves in all copper-treated plants following 4 weeks of treatment. 相似文献
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A three-dimensional model for the migration of colloids in a saturated fracture is presented, which considers the motion of colloids as a result of advection and diffusion, as well as colloid-surface interactions at the fracture walls. This model is successfully incorporated into a three-dimensional particle tracking algorithm that tracks particles within a continuum and allows consideration of the migration of colloids in symmetrical, three-dimensional, non-uniform fractures. The framework is general enough to incorporate non-local interactions that provide colloid motion relative to the fluid. The algorithm is verified against classical Taylor dispersion, and its generalization to a sorbing phase, in a uniform fracture and shows excellent agreement with theory. A simple, non-uniform fracture that has an analytically tractable velocity field is also considered, and both quantitative and qualitative comparisons are made with the uniform fracture case. The modelling of more complex fracture geometries is also discussed and a particular case is implemented within the particle tracking framework. 相似文献
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Books
The age of the molecule 相似文献545.
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Peter Orris M.D. John R. Kominsky M.S. Daniel Hryhorczuk M.D. James Melius M.D. 《Chemosphere》1986,15(9-12):1305-1311
A Polychlorinated Biphenyl (PCB) containing transformer released approximately 50 gallons of askarel oil. No polychlorinated dibenzofurans (PCDF) or polychlorinated dibenzodioxins (PCDD) were detected in a sample of the askarel (analytical limit of detection of 40 parts per billion per isomer group). Skin irritation, unusual tiredness, and headaches occurred in approximately 20% of the individuals at the scene of the incident. Serum PCB levels, and mean values for blood and urine tests were within normal ranges. 相似文献
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