Citation:

Henderson, A., B. Niblick, Heather E Golden, AND Jane C Bare. Modeling spatially resolved characterization factors for eutrophication potential in life cycle assessment. INTERNATIONAL JOURNAL OF LIFE CYCLE ASSESSMENT. Ecomed Verlagsgesellschaft AG, Landsberg, Germany, 26:1832-1846, (2021). https://doi.org/10.1007/s11367-021-01956-4

Impact/Purpose:

Excess nutrients from soil runoff and the atmosphere can lead to water quality challenges, such as harmful algal blooms (HABs) and depletion of oxygen, known as hypoxia. Life cycle assessment (LCA) measures some of these environmental impacts through the impact category "eutrophication potential". This work builds on a previous review by the authors of eutrophication models in LCA and calculates regionalized characterization factors to advance the scientific accuracy and effectiveness of this impact category. Once validated, these new characterization factors will be integrated into the next version of EPA's life cycle impact assessment model, TRACI (the Tool for Reduction and Assessment of Chemicals and other environmental Impacts).

Description:

Purpose: Prior versions of the Tool for Reduction and Assessment of Chemical and other environmental Impacts (TRACI) have recognized the need for spatial variability when characterizing eutrophication. However, the method’s underlying environmental models had not been updated to reflect the latest science. This new research provides the ability to differentiate locations with a high level of detail within the United States and provides global values at the country level. Methods: In previous research, the authors reviewed a broad range of domain-specific models and life cycle assessment methods for characterization of eutrophication and ranked these by levels of importance to the field and readiness for further development. The current research is rooted in the fundamental decision to separate freshwater and marine eutrophication to allow for the most tailored characterization of each category individually. It also assumes that freshwater systems are limited by phosphorus and marine systems are limited by nitrogen. Using a combination of spatial modeling methods for soil, air, and water, the current research calculates midpoint characterization factors for freshwater and marine eutrophication categories and evaluates the results through a US-based case application. Results and discussion: Maps of the nutrient inventories, characterization factors, and overall impacts of the case application illustrate the spatial variation and patterns in the results. The importance of variation in geographic location is demonstrated using nutrient data likelihood categories of agricultural (rural fertilizer), non-agricultural (urban fertilizer), and general (human waste processing). Proximity to large bodies of water, as well as individual hydraulic residence times, were shown to affect the comparative values of characterization factors across the US. Conclusions: In this paper, we have calculated and applied finely resolved freshwater and marine eutrophication characterization factors for the US and country-level factors for the rest of the globe for use within TRACI. Additional research is needed to provide similarly resolved characterization factors for the entire globe, which would require significant expansion of publicly available data as well as further development of applicable fate and transport models. Further developments may also be considered as computing capabilities become more sophisticated and widely available for scientific use.

URLs/Downloads:

Record Details: