Life Cycle Assessment of CCA-Treated Wood Marine Piles in the U.S. with Comparisons to Concrete, Galvanized Steel, and Plastic Marine Piles

摘要

A cradle-to-grave life cycle assessment is done to identify the environmental impacts related to chromated copper arsenate (CCA)-treated softwood used for marine piles in order to understand the processes that contribute to the total impacts and to determine how the impacts compare to those of the alternative products: concrete, galvanized steel, and plastic. Harbor and port authorities, as well as the public and regulatory interests, have increasing need to understand the environmental implications of marine piling material selection, in addition to factors such as cost and service performance. This study uses a life cycle inventory (LCI) to catalog the input and output data from marine pile manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to evaluate environmental impact indicators including: greenhouse gas (GHG) emissions, fossil fuel and water use, and emissions with the potential to cause acidification, smog, ecotoxicity, and eutrophication. Comparisons of pile products are made at a functional unit of one pile per year of service using primary manufacturing data for treated wood piles and representative data for the alternative products. This life cycle assessment (LCA) finds that the manufacture, use, and disposition of CCA-treated wood marine piles offers lower fossil fuel use and lesser LCIA indicators than competing products manufactured of concrete, galvanized steel, and plastic, while water use is lower for two of the three alternative products. Marine ecotoxicity evaluation was beyond the scope of this project and is best investigated using site specific modeling.