WATER USE IMPACTS

Regional characterization of freshwater use in LCA: Modeling direct impacts on human health

Anne-Marie Boulay, Cécile Bulle, Jean-Baptiste Bayart, Louise Deschênes and Manuele Margni

Article available online : http://pubs.acs.org/doi/pdf/10.1021/es1030883

E-mail: anne-marie.boulay@polymtl.ca

Abstract: Life cycle assessment (LCA) is a methodology that quantifies potential environmental impacts for comparative purposes in a decision-making context. While potential environmental impacts from pollutant emissions into water are characterized in LCA, impacts from water unavailability are not yet fully quantified. Water use can make the resource unavailable to other users by displacement or quality degradation. A reduction in water availability to human users can potentially affect human health. If financial resources are available, there can be adaptations that may, in turn, shift the environmental burdens to other life cycle stages and impact categories. This paper proposes a model to evaluate these potential impacts in an LCA context. It considers the water that is withdrawn and released, its quality and scarcity in order to evaluate the loss of functionality associated with water uses. Regionalized results are presented for impacts on human health for two modeling approaches regarding affected users, including or not domestic uses, and expressed in disability-adjusted life years (DALY). An illustrative example is presented for the production of corrugated board with different effluents, demonstrating the importance of considering quality, process effluents and the difference between the modeling approaches.

Google Earth Layer

The Google Earth layers available below present different indicators for the assessment of impacts from water use. A generic country-wide layer is provided if no specific data on the watershed is known, otherwise, the watershed layer should be used.

Simplified Indicator

This indicator is independent of quality input and output. It is available for the use of surface or ground resource. When the input resource is unknown, the “unspecified” data can be used as it is a weighted average of surface and ground water indicators based on the withdrawal fraction of each resource. The midpoint and endpoint parameters can be used to calculate the resulting impacts with the following equation1, where CF refers to alpha (midpoint) or CFHH (endpoint):

Impacts = (Volume input x CFin) - (Volume output x CFout)

Two different hypotheses are available at the endpoint: distribution or marginal. In the distribution hypothesis, the users affected are distributed according to the fraction of off-stream use that can be attributed to them. In the marginal hypothesis, only one off-stream user is set to be affected. The default marginal user affected is set to agriculture, as explained in Boulay et al(1).

Specific Indicator

These indicators are used in the same manner as the Simplified indicator, but are specific to the quality of the water entering and leaving the system. Water Qualities are described in the table below, based on Boulay et al(2) where quantitative description can be found.

Number 1 2a 2b 2c 2d 3 4 5
Name Excellent Good Average Average Tox AverageBio Poor Very Poor Unusable
Qualitative Description low bio
low toxic
low bio medium toxic Medium bio medium toxic Low bio higher toxic High bio low toxic High bio medium toxic High bio high toxic Other - Unusable

Water category calculator

The dynamic water tool is used to calculate quality parameters, water category of a country by default or a watershed. Software (Excel document)

Categorizing water for LCA inventory

Article available online : http://link.springer.com/article/10.1007%2Fs11367-011-0300-z

Abstract : Purpose As impact assessment methods for water use in LCA evolve, so must inventory methods. Water categories that consider water quality must be defined within life cycle inventory. The method presented here aims to establish water categories by source, quality parameter and user. Materials and methods Water users were first identified based on their water quality requirements. A list of parameters was then defined, and thresholds for these parameters were determined for each user. The thresholds were based on international standards, country regulations, recommendations and industry standards. Three different water sources were selected: surface water (including seawater), groundwater and rainwater. Based on the quality and water sources, categories were created by grouping user requirements according to the level of microbial or toxic contamination that the user can tolerate (high, medium or low). Results and discussion Seventeen water categories were created: eight for surface water, eight for groundwater and one for rainwater. Each category was defined according to 136 quality parameters (11 conventional parameters, 38 specific inorganic contaminants and 87 specific organic contaminants) and the users for which it can be of use. Conclusions A set of elementary flows is proposed in order to support a water inventory method oriented towards functionality. This can be used to assess potential water use impacts caused by a loss of functionality for human users.

  1. Boulay, A.-M.; Bulle, C.; Bayart, J.-B.; Deschenes, L.; Margni, M. Regional Characterization of Freshwater Use in LCA: Modeling Direct Impacts on Human Health Environmental Science & Technology 2011, 45, 8948-8957.
  2. Boulay, A.-M.; Bouchard, C.; Bulle, C.; Deschênes, L.; Margni, M. Categorizing water for LCA inventory The International Journal of Life Cycle Assessment 2011, 16, 639-651.

Find below a Google Earth Layer presenting these results at the country or watershed level.

Watershed level
 
 
Country level