Eutrophication footprints of foods and comparison to carbon footprints

Xiaobo Xue*, University of Pittsburgh
Amy Landis, University of Pittsburgh

Vast quantities of food is demanded to satisfy basic human needs every day. Food supply has become an important contributor to the depletion of natural resources and water quality degradation. Excessive nutrients exported from farming and food processing activities already has resulted in serious hypoxia and eutrophication issues in surrounding ecosystems 1. Changing food consumption patterns offers a unique opportunity for consumers to lower their personal eutrophication footprints. Concerned consumers are calling for mitigating environmental burden of food supply. Policymakers and producers therefore require scientifically defensible information about food products and production systems. Despite significant recent public concern and scientific attention to environmental impacts of foods mainly focused on their Carbon footprints, few studies have systematically compared the life cycle nutrients flows among different food types2. A few studies exist which look at overall diet but these have been focused on the relevance of carbon footprint and food consumption pattern. The study of nitrogen and phosphorus inventories for food categories and the potential of reducing nitrification through shifting food consumption patterns have not yet been addressed. This study utilizes a life cycle assessment (LCA) approach to quantify the nitrogen flows during food production, processing, packaging and distribution stages over main food types. This study compares solutions to reduce excessive nitrogen outputs, evaluates effectiveness and efficiency of possible solutions. Results show that different food groups exhibit a largely variable nitrogen-intensity. While red meats exhibit the highest nutrient intensity among all food categories, cereals/carbohydrates has the lowest eutrophication potential. Dietary shifting from red meat to cereals/carbohydrates may be an effective way to mitigate eutrophication impacts resulting from food consumption.

References

1. Miller, S.E.; Landis, A.E.; Theis, T.L. Feature: Environmental tradeoffs of biobased production. Enviro. Sci.Technol. 2007,41(15), 5176-5182
2. Weber, C.L.; Matthews, H.S., Food-miles and the relative climate impacts of food choices in the United States, Enviro. Sci.Technol. 2008,42(10), 3508-3513

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