ABSTRACT

Cleanup of contaminated waste sites is a National priority to protect human health and the environment, while restoring land to productive uses. While there are uncertainties with understanding risk to individuals from exposure, the aim of this study was to focus on uncertainties and complexities for ecological systems, complicated by hundreds of species occupying any remediation site which participate in multiple-interacting food webs. The ability to better predict the effectiveness of remediation in fostering future ecosystems might facilitate remedy selection and improve strategic environmental management. This investigation examined (1) uncertainties in ecosystem processes, (2) uncertainties in exposure from contamination before remediation, and (3) uncertainties during remediation. Two Department of Energy sites Hanford Site and Savannah River Site were used as case studies to illustrate how the uncertainties affect eco-receptors. Several types of ecological, physical, and human dimension uncertainties are defined. Ecological uncertainties include temporal, spatial, individual, developmental, and exogenous types. Physical uncertainties are weather-related, watershed variations, slope/aspect, soil/sediment structure and form, unforeseen events, and temporal patterns. Human dimension uncertainties include current land use, future land use, extractive and non-extractive recreation. The effects of remedial strategies varied between the two sites because Hanford is a primarily arid shrub-steppe ecotype, while Savannah River is a wet forest ecotype. Defining the associated ecological sensitivities and uncertainties and providing examples might help policy-makers, managers, planners, and contractors to be aware of issues to consider throughout planning, remediation, and restoration. Adding ecological uncertainty analysis to risk evaluations and remediation planning is analogous to using safety factors in human health risk assessment.

摘要

清理受污染的废物场地是国家优先事项，以保护人类健康和环境，同时恢复土地的生产用途。虽然理解暴露对个人的风险存在不确定性，但本研究的目的是关注生态系统的不确定性和复杂性，数百种物种占据任何修复地点，参与多重相互作用的食物网。更好地预测补救措施在培育未来生态系统方面的有效性的能力可能会促进补救措施的选择并改善战略环境管理。该调查检查了 (1) 生态系统过程的不确定性，(2) 修复前污染暴露的不确定性，以及 (3) 修复过程中的不确定性。能源部的两个站点汉福德站点和萨凡纳河站点被用作案例研究，以说明不确定性如何影响生态受体。定义了几种类型的生态、物理和人类维度的不确定性。生态不确定性包括时间、空间、个体、发展和外源类型。物理不确定性是与天气相关的、流域变化、坡度/坡度、土壤/沉积物结构和形式、不可预见的事件和时间模式。人类维度的不确定性包括当前土地利用、未来土地利用、采掘和非采掘娱乐。由于汉福德主要是干旱的灌木草原生态型，而萨凡纳河是潮湿的森林生态型，因此两个地点的补救策略的效果各不相同。定义相关的生态敏感性和不确定性并提供示例可能有助于政策制定者、管理者、规划者和承包商了解在整个规划、修复和恢复过程中要考虑的问题。将生态不确定性分析添加到风险评估和修复计划中类似于在人类健康风险评估中使用安全因素。