tailieunhanh - Ecological Risk Assessment for Contaminated Sites - Chapter 10

Đánh giá bài viết, khắc phục hậu quả Michael Faraday, trích dẫn trong Johnson (1991) Người đàn ông chắc chắn ông là gần như chắc chắn là sai, và ông có thêm bất hạnh không tránh khỏi còn lại như vậy. Quá trình thẩm định không nhất thiết phải kết thúc với việc hoàn thành của một hành động khắc phục hậu quả. Nếu các chất gây ô nhiễm không phải tất cả loại bỏ hoặc bị phá hủy hoặc nếu môi trường không được khôi phục vào một trạng thái có thể chấp nhận được bởi các hành động khắc phục hậu. | 10 Post-Remedial Assessments The man who is certain he is right is almost sure to be wrong and he has the additional misfortune of inevitably remaining so. Michael Faraday quoted in Johnson 1991 The assessment process does not necessarily end with the completion of a remedial action. If the contaminants are not all removed or destroyed or if the environment is not restored to an acceptable state by the remedial action it may be necessary to perform additional sampling analysis and assessment. These monitoring and assessment activities have two purposes 1 to ascertain whether additional remedial actions are needed and 2 to estimate the residual contaminant-induced injuries to the environment to determine what restoration activities are needed. Although these purposes are closely related they are procedurally distinct under . regulations and therefore are discussed separately below. A potential collateral purpose of these post-remedial assessments is to provide a basis for testing the predictions made in the prior assessments. Like any other activity based on scientific principles the predictions of risk assessments must be tested to prevent the complacency of which Faraday warned. REMEDIAL EFFICACY Remedial actions seldom remove or destroy all contaminants and some simply control uses of the site. It is advisable to monitor incompletely cleaned environments to establish that the remedial actions were adequate and that unacceptable risks do not persist. The EPA notes that the efficacy of ecological risk reduction is sometimes easier to observe than that of human health risk reduction. The agency recommends that the effectiveness of remedial actions be assessed following their implementation Sprenger and Charters 1997 . In many cases biological monitoring will provide a better indication of risk reduction than simple contaminant monitoring Fox 1993 . In addition the extent and rate of ecological recovery following the selection of the no-action alternative .