Henderson Andrew D, Niblick Briana, Golden Heather E, Bare Jane C
School of Public Health, University of Texas, Austin, TX 78701, USA.
Center for Environmental Solutions and Emergency Response, US Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
Int J Life Cycle Assess. 2021;26:1832-1846. doi: 10.1007/s11367-021-01956-4.
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 USA and provides global values at the country level.
In previous research (Morelli et al. 2018), 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 decision outcome of Morelli et al. (2018) to separate freshwater and marine eutrophication to allow for the most tailored characterization of each category individually. The current research 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, we calculate midpoint characterization factors for freshwater and marine eutrophication categories and evaluate the results through a US-based case application.
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-based activity 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, was shown to affect the comparative values of characterization factors across the USA.
In this paper, we have calculated and applied finely resolved freshwater and marine eutrophication characterization factors for the USA and country-level factors for the rest of the globe. Additional research is needed to provide similarly resolved characterization factors for the entire globe, which would require expansion of publicly available data and further development of applicable fate and transport models. Further scientific advances may also be considered as computing capabilities become more sophisticated and widely accessible.
《化学及其他环境影响的减少与评估工具》（TRACI）的先前版本已认识到在描述富营养化时考虑空间变异性的必要性。然而，该方法的基础环境模型尚未更新以反映最新科学。这项新研究能够在美国境内以高度详细的程度区分不同地点，并提供国家层面的全球数值。
在先前的研究中（莫雷利等人，2018年），作者回顾了一系列用于描述富营养化的特定领域模型和生命周期评估方法，并根据其对该领域的重要程度和进一步发展的准备程度进行了排名。当前的研究基于莫雷利等人（2018年）的决策结果，将淡水和海洋富营养化分开，以便对每个类别进行最具针对性的描述。当前研究还假定淡水系统受磷限制，海洋系统受氮限制。通过结合土壤、空气和水的空间建模方法，我们计算了淡水和海洋富营养化类别的中点特征因子，并通过一个基于美国的案例应用来评估结果。
案例应用的养分清单、特征因子和总体影响地图展示了结果中的空间变异和模式。利用基于养分的农业（农村肥料）、非农业（城市肥料）和一般（人类废物处理）活动可能性类别，证明了地理位置差异的重要性。靠近大型水体以及各个水力停留时间被证明会影响美国各地特征因子的比较值。
在本文中，我们计算并应用了美国精细解析的淡水和海洋富营养化特征因子以及全球其他地区的国家层面因子。需要进行更多研究以提供全球范围类似解析的特征因子，这将需要扩展公开可用数据并进一步开发适用的归宿和迁移模型。随着计算能力变得更加复杂且广泛可用，也可考虑进一步的科学进展。
