128 SEDIMENTARY ROCKS/Phosphates Environmental Significance of Phosphate Phosphorus is essential for all forms of life Considerable cycling of phosphorus takes place within the biosphere and interchange occurs between ecosystems While the overwhelming amount of phosphorus fluxing takes place between marine organisms and ocean water, human activities play a significant role at the ecosystem scale The widespread use of phosphatebased fertilisers and insecticides, the disposal of sewerage sludge and industrial waste, including some derived from nuclear reactors, are examples of larger-scale processes that can have serious environmental impacts Perhaps the best known involves the overload of phosphorus in streams and lakes, leading to an explosion of plant life, especially algae, which upon decay uses up most of the dissolved oxygen This process, known as eutrophication, results in fish kills (see Fossil Vertebrates: Fish) and degradation of water quality On a more restricted scale, there is some evidence for the formation of lead phosphates such as plumbogummite–crandallite and pyromorphite–apatite in soils verging on roads and highways used by vehicles burning leaded gasoline Increasing awareness of all these problems has meant that control programmes are in place in many regions Phasing out of lead-based fuels and phosphate-based detergents, together with possible use of crystalline phosphates and phosphate glasses for nuclear waste immobilization, are also helping to improve environmental outcomes See Also Africa: North African Phanerozoic Analytical Methods: Fission Track Analysis Fossil Vertebrates: Fish Igneous Rocks: Granite Minerals: Definition and Classification Plate Tectonics Sedimentary Environments: Depositional Systems and Facies Sedimentary Rocks: Mineralogy and Classification Further Reading Anthony JW, Bideaux RA, Bladh KW, and Nichols MC (2000) Handbook of Mineralogy Volume IV: arsenates, phosphates, vanadates USA, Tucson: Mineral Data Publishing Birch WD and Henry DA (1993) Phosphate Minerals of Victoria Australia, Melbourne: Mineralogical Society of Victoria Inc Cook PJ (1984) Spatial and temporal controls on the for mation of phosphate deposits a review In: Nriagu JO and Moore PB (eds.) Phosphate Minerals, pp 242 274 Germany, Berlin: Springer Verlag Filippelli GM (2002) The global phosphorus cycle In: Kohn KJ, Rakovan J, and Hughes JM (eds.) Phos phates: Geochemical, Geobiological and Materials Im portance, Reviews in mineralogy and geochemistry 48, pp 391 425 Washington, DC: Mineralogical Society of America Gleadow AJW, Belton DX, Kohn BP, and Brown RW (2002) Fission track dating of phosphate minerals and the ther mochronology of apatite In: Kohn KJ, Rakovan J, and Hughes JM (eds.) Phosphates: Geochemical, Geobiolo gical and Materials Importance, Reviews in mineralogy and geochemistry 48, pp 579 630 Washington, DC: Mineralogical Society of America Hill C and Forti P (1997) Cave Minerals of the World USA, Alabama: National Speleological Society Inc Huminicki DMC and Hawthorne FC (2002) The crystal chemistry of the phosphate minerals In: Kohn KJ, Rakovan J, and Hughes JM (eds.) Phosphates: Geochem ical, Geobiological and Materials Importance, Reviews in mineralogy and geochemistry 48, pp 123 253 Washington, DC: Mineralogical Society of America Kostov I and Breskovska V (1989) Phosphate, Arsenate and Vanadate Minerals Crystal Chemistry and Classifi cation Bulgaria, Sofia: Kliment Ohridski University Press Moore PB (1973) Pegmatite phosphates: descriptive miner alogy and crystal chemistry The Mineralogical Record 4: 103 130 Nash WP (1984) Phosphate minerals in terrestrial igneous and metamorphic rocks In: Nriagu JO and Moore PB (eds.) Phosphate Minerals, pp 215 241 Germany, Berlin: Springer Verlag Piccoli PM and Candela PA (2002) Apatite in igneous systems In: Kohn KJ, Rakovan J, and Hughes JM (eds.) Phosphates: Geochemical, Geobiological and Materials Importance, Reviews in mineralogy and geochemistry 48, pp 255 292 Washington, DC: Mineralogical Society of America Robinson GW, Velthuizen J van, Ansell HG, and Sturman BD (1992) Mineralogy of the Rapid Creek and Big Fish River area, Yukon Territory The Mineralogical Record 23(4): 47 Spear FS and Pyle JM (2002) Apatite, monazite and xeno time in metamorphic rocks In: Kohn KJ, Rakovan J, and Hughes JM (eds.) Phosphates: Geochemical, Geobiolo gical and Materials Importance, Reviews in mineralogy and geochemistry 48, pp 293 255 Washington, DC: Mineralogical Society of America Williams PA (1990) Oxide Zone Geochemistry England, Chichester: Ellis Horwood Limited