Health & Environmental Research Online (HERO)


Print Feedback Export to File
4243240 
Journal Article 
Phosphate rock: origin, importance, environmental impacts, and future roles 
Fayiga, AO; Nwoke, OC 
2016 
Yes 
Environmental Reviews
ISSN: 1181-8700
EISSN: 1208-6053 
24 
4 
403-415 
WOS:000388735900004 
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. Chemical analysis of PR obtained from top PR-producing countries, however, shows that hazardous elements contained therein are below tolerable limits for PO43- fertilizers. Studies have also reported that the radionuclides in PR do not pose any radiological risk. The presence of these elements in PR can be put to positive use if they are extracted before they are applied to farmlands. This makes PR a source of rare earth metals and radionuclides that could be used in technological development and as a future energy source. The affinity of PR for metals makes it a useful adsorbent for the removal of metals from aqueous solutions and an excellent material for metal immobilization in contaminated soils. PR is a very important finite resource but its applications have adverse environmental implications. 
phosphate rock; apatite; phosphate fertilizer; radionuclides; environmental pollution