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91.
Effects of Regional Reductions in Sulphur Deposition on the Chemical and Biological Recovery of Lakes within Killarney Park, Ontario, Canada 总被引:3,自引:0,他引:3
Snucins E Gunn J Keller B Dixit S Hindar A Henriksen A 《Environmental monitoring and assessment》2001,67(1-2):179-194
The lakes in KillarneyProvincial Park, located 40–60 km southwest ofSudbury, Ontario, were some of the first lakesin North America to be acidified by atmosphericpollutants. Acidification affected thousandsof fish and invertebrate populations in dozensof lakes. Since the 1970's, water quality hasimproved in response to atmospheric pollutionreductions and some lakes have alreadyrecovered to approximately their pre-industrialpH levels, as inferred from diatom microfossilsin lake sediments. Since the 1970's, fishspecies richness has not changed substantially,but zooplankton species richness has increasedin acidified lakes. The critical sulphur load,the amount of SO2-derived acid depositionthat can occur while still maintaining suitable water quality, was estimated to beexceeded in 38% of the park area in 1997. Depending on which of four possible NorthAmerican emission control scenarios (CLR =currently legislated reduction; CLR + 25%; CLR+ 50%; CLR + 75%) is achieved by 2010, theprojected critical loads will be exceeded inabout 0-30% of the park area in the future. There are many factors that can affectbiological recovery rates of damaged lakes, butit is expected that biological recovery willlag considerably behind observed chemicalrecovery rates. 相似文献
92.
Hoenicke R Davis JA Gunther A Mumley TE Abu-Saba K Taberski K 《Environmental monitoring and assessment》2003,81(1-3):15-25
The San Francisco Estuary Regional Monitoring Program (RMP) for Trace Substances is an innovative partnership among a regulatory agency, more than 70 regulated entities, and an independent scientific organization. The institutional arrangement behind the RMP has made the regulatory system increasingly responsive to emerging management needs, particularly with regard to the development of total maximum daily loads and ecosystem impairment assessment. Through multi-agency partnerships within and outside the RMP institutional structure, major information gaps for several pollutants of concern have been narrowed, resulting in a successful consensus-based regulatory approach to managing copper and nickel mass inputs into the Estuary. Short-term research efforts, based upon monitoring results, helped identify the most cost-effective control and remediation options for various bioaccumulative substances. Additionally, adaptive changes to the monitoring program documented the existence of widespread aquatic toxicity in the Estuary that is apparently due to pesticide runoff from agricultural and urban areas. One of the most important contributions of this collaborative monitoring program is the deliberate and systematic adjustment of management and research questions that serve to influence and add relevance to the overall research agenda related to San Francisco Estuary ecosystem assessment. 相似文献
93.
在简要介绍了TiO2光催化降解机理的基础上,综述了影响纳米TiO2光催化性能的因素及提高其光催化能力的途径。 相似文献
94.
95.
东莞运河水环境容量优化研究 总被引:3,自引:0,他引:3
本文根据东莞运河的特点,建立了适用运河特点的水环境容量优化模型,求解运河在不同的运行规律下最大的水环境容量值。建立的模型简单,易于求解,求解方程可以直接引用线性规划软件,计算得到的结果正确。 相似文献
96.
97.
为了老城区河道的合理整治,采用总有机碳(TOC)分析仪对常州市老城区3条河流及区域内浅层地下水的14个采样点水样进行3个月的总有机碳含量检测。老城区水环境受到不同程度的有机污染,某些地下水的TOC含量高于地表水,原因为地表水补给地下水,且老城区水体污染源主要来源于周边地区的生活污水,并受到关河、雨水等的影响,这为常州市老城区水污染治理提供了依据。 相似文献
98.
For characterisation of landscapes in north-eastern Estoniaaffected by alkaline oil shale fly ash and cement dust the zonation-method based on average annual (C
y) and short-termconcentrations of pollutants in the air was used, as well as on deposition loads of dust and Ca2+. In the overground layer of atmosphere the zones with different air pollution loads were distinguished. A comparative analysis of pollution zones characteristics and biomonitoring data revealed that for sensitive lichen the dangerous level of alkaline dust in the air, introducingthe degradation of Sphagnum sp. at the level of C
y of dust 10–20 g m-3 and at 0.5–1 hr maximums 100–150 g m-3. For Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) this limited concentration (decline of growth parameters) of cement dust is correspondingly following: 30–50 g m-3 and 150–500 g m-3, in case of fly ash the limit level of C
y amounting 100 g m-3. Daily deposition load of Ca2+ should not exceed approximately 4.5–15 mg m-2 for lichen; for conifers the harmful pollution load is higher – >22 mg m-2. 相似文献
99.
以马尾松为指示植物,对韶关的土壤进行了长期淋溶模拟并记录其化学状态。结果发现,土壤溶液的pH值下降到4.0,Bs值下降到几乎为零,有较大量的A1离子溶出。最后选取土壤溶液pn〉4.0、KS〉10%和[Al^3+]〈0.1mmol/L为临界化学指标,参考国内外应用广泛的MAGIC模型和SMART模型,确定韶关酸沉降临界负荷(S的临界负荷)为14.1keq/hm^2.a。 相似文献
100.
动荷载作用下边坡锚固系统合理设计探讨 总被引:1,自引:0,他引:1
爆破、地震或列车振动等动荷载作用下,边坡锚固系统易产生锚筋松弛、夹具损伤、注浆体拉裂及界面粘结失效等情况,影响其预应力赋存状态、加固效果和耐久性。基于动荷载作用类型和锚固系统动力响应特征分析,提出了动载下不同地层内的锚固段合理结构设计方案和锚筋抗拉安全系数及锁定荷载的建议。动载下自由段(外锚固段)宜设计为全粘结型或增设多级反锚装置,形成岩土自锁锚固,以控制预应力损失和防止锚头或自由段破断造成突发性灾害;在水泥基灌浆体中掺入钢纤维或树脂纤维,可改善锚固体抗裂性能,提高其抗疲劳和抗冲击能力;建议优先采用防腐性能卓越的填充型环氧涂层钢绞线,以提高锚固体在动载破裂时的耐久性。 相似文献