Phosphate rock: origin, importance, environmental impacts, and future roles

Phosphate rock (PR) is an important mineral resource with numerous uses and applications in agriculture and the environment. PR is used in the manufacture of detergents, animal feed, and phosphate (PO43–) fertilizers. Leaching or runoff losses from PR products like PO43– fertilizers, animal feeds, and detergents could cause eutrophication of surface waters enriched in PO43– by these losses. Although direct application of PR reduces pollution by acting as a slow-release fertilizer, its effectiveness is limited by several factors. The major limitation of PR in direct application is its low solubility, which reduces its availability for soil reactions or plant uptake. Strategies used to increase the effectiveness of directly applied PR are based on increasing acidity, as this increases PR solubility. The application of PR in agriculture may have adverse effects because it contains hazardous elements that could be transferred to the soil through the application of fertilizers, especially after long term use. ...