The biogeochemical imprint of human metabolism in Paris Megacity: A regionalized analysis of a water-agro-food system

摘要

Megacities are facing a twofold challenge regarding resources: (i) ensure their availability for a growing urban population and (ii) limit the impact of resource losses to the environment. This paper focuses on two essential resources - nitrogen and phosphorus - and challenges their sustainable management in the water-agro-food system of Paris Megacity. An in-depth analysis of the nitrogen and phosphorus imprint of Paris Megacity was conducted, originally centered on human metabolism through consumption and excretion of these two elements. Upstream, the whole agricultural production that feeds Paris Megacity was scrutinized and nitrogen and phosphorus flows in the agro-system were fully documented. Downstream, the analysis of solid waste and wastewater management in Paris Megacity showed the fate of nitrogen and phosphorus imported into the city.