Towards a closed phosphorus cycle

Summary: This paper stresses the need to address upcoming scarcity of phosphorus, a mineral nutrient that is essential for all life on Earth. Agricultural crops obtain phosphorus from the pool in the soil that can be replenished by recycling of organic material, or by application of inorganic fertilizer, originating from mines, largely concentrated in three countries only: Morocco/Western Sahara, China and USA. A complicating factor is that the phosphorus rock contains other substances as well, including the heavy metals cadmium and uranium. These substances currently end up in fertilizer and in phosphogypsum where they may pose threats to human and animal health. Hence scarcity and environmental considerations call for action to close the phosphorus cycle. The paper compares two options for intervention: mandatory recycling versus a ban on imports of contaminated phosphorus, and argues in favor of the second. © 2010 The Author(s).