The Application of A Tiered Testing Approach to the Management of Dredged Sediments for Disposal at Sea in Canada

Canada, and other signatories to the London Convention 1972 on the prevention of marine pollution by dumping, are preparing to ratify a 1996 Protocol to this convention. Among the improvements to this international agreement, is a new process for the Assessment of Waste and Other Matter, which is to be adopted by signatory parties. the process includes a step in which material considered potentially acceptable for sea disposal must be characterized by chemical, physical and biological properties. Canada's interpretation and intended implementation of this characterization step is presented for the assessment of dredged sediments. This tiered testing approach involves using chemical screening limits for contaminants, and biological testing when screening levels are exceeded. Dredged material containing specified substances (e.g., cadmium, mercury, PAHs, PCBs, etc.) below or at screening levels would generally be considered of little environmental concern for disposal at sea. Wastes above the screening levels would require more detailed assessment before their suitability for disposal at sea could be determined.     

1996年7月湖南益阳特大水灾分析

全面科学地分析了1996年7月湖南益阳夏季特大水灾的历史背景、特点及防御对策，对综合治理洞庭湖提供了科学依据。     

The Application of A Tiered Testing Approach to the Management of Dredged Sediments for Disposal at Sea in Canada

Canada, and other signatories to the London Convention 1972 on the prevention of marine pollution by dumping, are preparing to ratify a 1996 Protocol to this convention. Among the improvements to this international agreement, is a new process for the Assessment of Waste and Other Matter, which is to be adopted by signatory parties. the process includes a step in which material considered potentially acceptable for sea disposal must be characterized by chemical, physical and biological properties. Canada's interpretation and intended implementation of this characterization step is presented for the assessment of dredged sediments. This tiered testing approach involves using chemical screening limits for contaminants, and biological testing when screening levels are exceeded. Dredged material containing specified substances (e.g., cadmium, mercury, PAHs, PCBs, etc.) below or at screening levels would generally be considered of little environmental concern for disposal at sea. Wastes above the screening levels would require more detailed assessment before their suitability for disposal at sea could be determined.     

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以二维非恒定流和不平衡输沙理论为基础,建立了黄河下游高村至孙口河二维水沙运动数值模型,对１９９６年异常洪水的滩槽水流运动、泥沙冲淤进行了分析计算．计算结果充分反映了模型对黄河来水来沙变幅大的适应能力,以及对滩槽水沙交换、滩区生产堤对洪水演进影响的合理模拟．     

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简要论述了1996年江西省境内发生的4次严重的洪涝灾害,总结防汛减灾中的成功经验;针对洪涝灾害抗灾救灾中存在的几个主要问题,探讨今后防讯减灾对策。