Environmental full cost accounting of alternative materials used for railroad ties: Treated-wood and concrete case study

Abstract

Environmental full-cost accounting (FCA) is a novel analytical framework that describes ecological and human health impacts of products and processes using financial measures. These impacts are generally considered to be external to the cost of the product, and are not traditionally reflected in the sales price of the product or service. FCA methodology provides a novel framework to analyze product alternatives from an inclusive perspective considering economic, societal, and environmental impacts. In this work, researchers use the FCA methodology to compare a series of chemically treated wooden and concrete railroad crossties. For all products analyzed in the study, production of the treatment chemicals and the crosstie, use, and disposal stages were included along with mass of emissions, and associated health and environment costs. This FCA allows for a comparison of alternatives products and insight into the implications of final disposal. Two alternative end of life (EOL) scenarios were explored, e.g., energy recovery where the chemically treated wood is burned for energy production, and disposal in a landfill. This work shows that the EOL scenario for treated crossties play a dominate role when defining environmental and social costs. This contrasts with concrete crossties, where the production stage is the main contributor. Wood treatment utilizing copper-chrome-arsenic (CCA) represents a worst case EOL scenario due to high costs associated with atmospheric emissions of arsenic and CO2. Finally, depending on how biogenic CO2 is treated, concrete or furfuryl alcohol treated wood had the lowest environmental price.