River and harbor remediation: 'polluter pays,' alternative finance, and the promise of a 'circular economy'

摘要

Purpose Contaminated sediments in rivers, lakes, and harbors around the world result in diminished ecological health, degradation of environmental resources, economic losses, and, in rare cases, impacts on human health. Despite the ongoing interest in the cleanup of contaminated sediments in rivers and harbors, little progress has been made in reducing the number of contaminated sites worldwide. Proponents of a "circular economy" model assert that it can facilitate the cleanup of contaminated sediments through product and process design to eliminate waste of resources, to beneficially use (and reuse) products and materials, and to restore ecologies. This paper evaluates the application of circular economy models to practice in the treatment, removal, and processing of contaminated sediments found in waterways. Materials and methods No materials were used in this work. Methods consisted of literature research and review. Results and discussion Much of the difficulty in advancing the cause of contaminated sediment cleanup can be attributed to the high cost of cleanups and the difficulty in assigning financial responsibility for the cost. Simple schemes dependent on identifying polluters are fraught with underlying complexity. More elaborate approaches tied in with waterfront redevelopment show some promise but are yet to be applied routinely. New advances in the understanding of how sediments may, or may not, factor into the utility of circularity models pose new challenges and opportunities, with the potential to complement new funding paradigms. Conclusion The most promising possibilities for achieving circularity in sediment management lie in a kind of punctuated circularity, which requires individual, project-based beneficial use opportunities. However, these ideal situations are likely to remain rare for the foreseeable future, without advancements in technology and regulatory approaches, as well as development of market demand for the products made from contaminated sediments.