Freshwater consumption and domestic water deprivation in LCIA: revisiting the characterization of human health impacts

PURPOSE: An insufficient amount of available domestic water can lead to an increase in the occurrence of water-related diseases. No LCIA consensus has been reached on how to model the potential impacts on human health resulting from water use implying domestic water deprivation. Building on Boulay et al. (2011), this research work provides an updated and revisited characterization model and factors assessing the potential impact on human health induced along this impact pathway. METHOD: This work consolidates the cause-effect chain linking water use to domestic impacts on human health. The revised fate factor aligns current water use assessment methods and includes information not only on the physical water scarcity but also on the level of population access to water in a region. Building on Boulay et al. (2011), the global effect factor is revised. The data source is updated, and a novel approach is developed estimating the domestic water deficit. Country-scale exposure factors are updated, building on Boulay et al. (2011)’s proposal to rely on the gross national income per capita as a proxy for a country’s capacity to adapt to water shortages. RESULTS AND DISCUSSION: Compared to Boulay et al. (2011), the revised fate and exposure factors show lower values as a result of different methodological choices and of the overall increase of GNI per capita, respectively. The revised value of the effect factor is equal to 3.13E-3DALY/m3 which compares to the value of 3.11E-3 in Boulay et al. (2011). Revised characterization factors (CF) range from 0 DALY/m3 (the potential impact on human health due to water use is null with respect to domestic water deprivation) to 3.13E-3 DALY/m3. The distribution of the new CFs shows an order of magnitude decrease compared to the previous model. These CFs assess the consequences on human health induced by water use leading to short-term water deprivation. CONCLUSION AND RECOMMENDATIONS: This research work helps to better account for the impacts of water use at the endpoint level. However, it underlines significant limitations in the current calculation of the effect factor, in particular regarding current quantification of domestic water deprivation. These shortcomings prevent the model from considering a difference in vulnerability to health damages from the deprivation of 1 m³ of domestic water. This research work argues for additional research efforts aimed at developing an alternative calculation method for this factor.