Environmental and social LCA of growing media for urban rooftop farming
New environmental strategies are emerging for cities to become more self-sufficient, such as hydroponic crop production. The implementation of such systems requires materials that usually originate in countries with low labour costs and other legal regulations. To what extent could these strategies be shifting problems across the globe?
To answer this question, researchers performed a comprehensive environmental and social assessment of the various extended soilless systems used to grow vegetables on urban roofs. Three different growing media constituents were chosen for this study: perlite, peat, and coir, which are produced in three countries, Turkey, Germany, and the Philippines respectively, and are imported to Spain. By using a life cycle assessment, the researchers evaluated the environmental performances of the production and transport of these growing media.
Additionally, they performed a social life cycle assessment at different levels. First, they used the Social Hotspots Database to analyze the constituents in aggregated sectors. Second, they performed a social assessment at the country and sector levels, and finally, they evaluated primary company data for the social assessment of the constituents through questionnaires given to businesses.
The coir-based growing medium exerted the lowest environmental burden in 5 out of 8 impact categories because it is a by-product of coconut trees. In contrast, perlite obtained the highest environmental impacts. Regarding the social assessment, peat demonstrated the best performance on all the social assessment levels.
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