共查询到20条相似文献,搜索用时 880 毫秒
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《Waste management & research》1991,9(3):230-231
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W. Keller N. D. Yan J. M. Gunn J. Heneberry 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):317-322
Over 7,000 lakes around Sudbury, Ontario, Canada were acidified by S deposition associated with emissions from the Sudbury
metal smelters and more distant S sources. Air pollution controls have led to widespread changes in damaged Sudbury lakes,
including increased pH and decreased concentrations of SO4, metals and base cations. While chemical improvements have often been substantial, many lakes are still acidified, although
water quality recovery is continuing. Biological recovery has been observed in some lakes among various groups of organisms
including fish, zooplankton, phytoplankton and zoobenthos. Generally, however, biological recovery is still at an early stage.
Lakes around Sudbury are also showing that the recovery of acid-damaged lakes is closely linked to the effects of other major
environmental stressors such as climate change, base cation depletion and UV-B irradiance. Future studies of the recovery
of acid-damaged lakes around Sudbury, and in other regions, will need to consider the interactions of these and other stressors. 相似文献
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Major sulphur emission control programs have been implemented in North America, resulting in current emissions being ~30% less than those in 1980. However, the level of acidic deposition remaining is still unlikely to promote widespread recovery of aquatic ecosystems. The First-order Acidity Balance (FAB) model has been applied to south-central Ontario (285 lakes in the Muskoka River Catchment) to evaluate the need for further reductions in emissions. As a result of the past decline in deposition, the proportion of lakes with critical loads exceedance has dropped substantially; however, further reductions in sulphur and nitrogen emissions are required to eliminate critical loads exceedance. Based on bulk deposition of sulphate and nitrogen (41.1 mmolc m-2 yr-1 and 62.5 mmolc m-2 yr-1, respectively) for the period 1995–1999, 166 lakes (58.3%) exceedcritical loads. Even with full implementation of SO2 abatementprograms in Canada (achieved in 1994) and the United States (legislated for 2010), critical loads will be exceeded in a large proportion (46.6%) of the study lakes. 相似文献
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《Waste management & research》1991,9(1):68-70
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Poly(aspartic acid) is a biodegradable, water-soluble polymer that is valuable in numerous industrial applications. A variety
of synthetic methods can be utilized to prepare poly(aspartic acid) and related polymeric materials with a range of tailored
physical and chemical characteristics. This review of current investigative and patent literature describes methods of synthesis,
biodegradative studies, and important current and potential applications of both poly(aspartic acid) homopolymers and copolymers. 相似文献
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The thermal oxidative stability of various ABS/PC compounds was studied by means of the chemiluminescence technique. Similarly to pure ABS, Irganox 1076 and Irganox MD 1024 perform as moderate antioxidants in ABS/PC and (ABS/PC + lubricant) blends. Neither Tinuvin 144, Irgaphos 168, nor their mixture affects the durability of the ABS/PC blend. At the same time, (Irgaphos 168 + Tinuvin 144) in combination with Irganoxes was found to provide a noticeable enhancement in durability to the (ABS/PC + lubricant) system. Titanium dioxide pigments by themselves have only a slight influence on the oxidative stability of the ABS/PC blend. Durability of the (ABS/PC + pigment) and (ABS/PC + lubricant) systems was found to be the same and the overall protective effect of Irganox 1076 was similar in both the (ABS/PC + lubricant) and the (ABS/PC + lubricant + pigment) systems. Certain modifiers significantly improve the durability of the ABS/PC compounds, although their function may differ in the systems with and without pigments.Guest Editor: Dr. Graham Swift, Rohm & Haas. 相似文献
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《Waste management (New York, N.Y.)》2002,22(5):571-572
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《Waste management & research》1990,8(5):389-391
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《Waste management (New York, N.Y.)》2006,26(12):1490
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《Waste management & research》1990,8(4):312-314