The management lessons learned from sediment remediation in the Detroit River – western Lake Erie watershed

Abstract

AbstractDuring the 1970s−1990s, considerable emphasis was placed on minimizing the inputs of polychlorinated biphenyls (PCBs) from active sources. In addition, between 1993 and 2001, ≈ $US130 × 106 was spent for sediment remediation within the western Lake Erie – Detroit River basin. In general, although PCB contamination of the Detroit River and Lake Erie declined significantly between the 1970s and mid‐1990s, it has remained fairly stable over the past 10 years. Control of PCBs and other contaminants at their source remains a primary imperative for action. Remediation of contaminated sediments is growing in importance, however, as greater levels of source control are achieved. From a sediment management perspective, it is estimated that between 1993 and 2001 a substantially higher mass of PCBs (over two orders of magnitude higher) was removed as a result of contaminated sediment remediation, as compared to navigational dredging of shipping channels. In addition, there is a strong and compelling rationale for moving expeditiously to remediate severely contaminated sediment while it is still relatively contained in a small geographical area. The cost of not acting in a timely manner might be to exacerbate environmental problems including increased deformities and reproductive problems in wildlife, delayed ecosystem recovery and increased costs, or even preclusion of future sediment remediation. Based on discussions at a United States of America–Canada workshop held in 2002, key management advice includes continued emphasis to be placed on remediating contaminated sediment hot spots (including evaluating the effectiveness of projects), integrated monitoring efforts to be focused on beneficial use restoration and a high priority to be placed on sustaining and building upon modelling efforts, in order to be able to accurately predict and evaluate ecosystem responses to remedial and preventive actions.