Assessing phosphorus fluxes in Portugal

Phosphorus (P) has been shown essential in the food sector. Due to the global shortage of P nutrients and the dependence on imports of phosphorus products and by-products, many countries have developed strategies to track the flows of this nutrient in their national territory. This comprises assessing which sectors and subsectors are the most relevant and identifying potential interventions for its recovery with consequent reduction of imports. Previous studies estimated that the circularity of the supply chain offers the possibility of satisfying the demand for phosphorus and reduce significantly the European Union's dependence on imports. The present research focuses on estimating the value of P fluxes in the Portuguese territory through Substance Flow Analysis (SFA) methodology to evaluate phosphorus's circularity within its production/consumption chain, collecting demographic, spatial, and economic data. Due to the great diversity of information and sources, the accuracy and reliability of the calculated fluxes were evaluated. P flows were compared through indicators that measure the effectiveness of use, accumulation, and losses of P nutrients among other countries (the UK, USA, Australia, New Zealand, France, Finland, and Japan) that have assessed the chain of this nutrient. The results show that soil nutrient management in Portugal in 2013 was considerably efficient (Soil out/ Soil in = 79 %). However, the urban system appears with a high amount of P in landfills (35.38 kt) and in treated wastewater (0.87 kt). The solid waste sector has ongoing P recovery measures, as it already has organic material recovery activities and indirect P recovery (1.39kt). In the influent wastewater, there is a possibility of recovering 8.2 kt of P, however there are no efforts or policies aimed at valuing this nutrient, as the same time that infrastructure improvements are needed to reduce P discharges into water body.