Contaminated Sediments in Norway: From Single to Multi Criteria Decision Methods

摘要

Background/Objectives. Managing contaminated urban coastal areas is an important issue in today’s society. Harbor areas are transformed from industrial sites and shipyards, to housing areas with high environmental requirements. The use of coastal areas for aquaculture and fishing activities increases the need for cleanup of previous contamination sources. High environmental standards when handling dredged material from harbors and industrial activities are also required in our society today. Many countries including Norway have based the management for the coastal zone environment on use of health and ecological risk assessments (HERA). This means that there should be no adverse risk to human or ecological life due to exposure of contaminants from sediments or water. This single criteria framework based on the precautionary principle is inherently conservative and may introduce costly and resource consuming remediation methods with isolated focus on sediment disposal instead of beneficial use. Approach/Activities. This work describes two decision models to be used in contaminated sediment management in Norway. A participatory “bottom-up” multicriteria involvement process (MIP) for involvement of stakeholders in contaminated sediment management which has been evaluated for future sediment remediation in Bergen harbor. In addition an integrative “top-down” decision model incorporating social, environmental and economical values by use of stochastic multicriteria analysis has been evaluated for the Grenland fjord remediation project Moving from single criteria to multi criteria decisions in contaminated sediment management through implementing risk perceptive and sustainable values Results/Lessons Learned. Implementing the proposed decision models will be a step towards sustainable decisions in contaminated sediment management. Although there are substantial advantages to use a multicriteria approach in complex decisions, there are also difficulties in relation to use. It will, for example, require more openness in the decision making process and complementary competence among experts and consultants. For a successful implementation these challenges have to be overcome.