Geological occurrence , US, 2008 , Tunisia, 2012 Phosphates are the naturally occurring form of the element
phosphorus, found in many
phosphate minerals. In mineralogy and geology, phosphate refers to a rock or ore containing phosphate ions. Inorganic phosphates are
mined to obtain phosphorus for use in agriculture and industry.. Within North America, the largest deposits lie in the
Bone Valley region of central
Florida, the
Soda Springs region of southeastern
Idaho, and the coast of
North Carolina. Smaller deposits are located in
Montana,
Tennessee,
Georgia, and
South Carolina. The small island nation of
Nauru and its neighbor
Banaba Island, which used to have massive phosphate deposits of the best quality, have been mined excessively. Rock phosphate can also be found in Egypt, Israel, Palestine, Western Sahara,
Navassa Island, Tunisia, Togo, and Jordan, countries that have large phosphate-mining industries.
Phosphorite mines are primarily found in: •
North America: United States, especially Florida, with lesser deposits in
North Carolina,
Idaho, and
Tennessee •
Africa:
Morocco,
Algeria,
Egypt,
Niger,
Senegal,
Togo,
Tunisia,
Mauritania •
Middle East:
Saudi Arabia,
Jordan,
Israel,
Syria,
Iran and
Iraq, at the town of
Akashat, near the Jordanian border. •
Central Asia:
Kazakhstan •
Oceania:
Australia,
Makatea,
Nauru, and
Banaba Island In 2007, at the current rate of consumption, the supply of phosphorus was estimated to run out in 345 years. However, some scientists thought that a "
peak phosphorus" would occur in 30 years and
Dana Cordell from Institute for Sustainable Futures said that at "current rates, reserves will be depleted in the next 50 to 100 years". Reserves refer to the amount assumed recoverable at current market prices. In 2012 the
USGS estimated world reserves at 71 billion tons, while 0.19 billion tons were mined globally in 2011. Phosphorus comprises 0.1% by mass of the average rock (while, for perspective, its typical concentration in vegetation is 0.03% to 0.2%), and consequently there are quadrillions of tons of phosphorus in Earth's 3×1019-ton crust, albeit at predominantly lower concentration than the deposits counted as reserves, which are inventoried and cheaper to extract. If it is assumed that the phosphate minerals in
phosphate rock are mainly
hydroxyapatite and
fluoroapatite, phosphate minerals contain roughly 18.5% phosphorus by weight. If phosphate rock contains around 20% of these minerals, the average phosphate rock has roughly 3.7% phosphorus by weight. Some phosphate rock deposits, such as
Mulberry in Florida, from application of the resulting
phosphate fertilizer. In December 2012,
Cominco Resources announced an updated
JORC compliant resource of their Hinda project in
Congo-Brazzaville of 531 million tons, making it the largest measured and indicated phosphate deposit in the world. Around 2018, Norway discovered phosphate deposits almost equal to those in the rest of Earth combined. In July 2022 China announced quotas on phosphate exportation. The largest importers in millions of metric tons of phosphate are Brazil 3.2, India 2.9 and the USA 1.6.
Mining The three principal phosphate producer countries (China, Morocco and the United States) account for about 70% of world production.
Environmental Impacts of Mining Phosphate deposits can contain significant amounts of naturally occurring heavy metals. Mining operations processing
phosphate rock can leave
tailings piles containing elevated levels of
cadmium,
lead,
nickel,
copper,
chromium, and
uranium. Unless carefully managed, these waste products can leach heavy metals into groundwater or nearby estuaries. Uptake of these substances by plants and marine life can lead to concentration of toxic heavy metals in food products. == Ecology == in various regions of the ocean. Note that nitrate is more often limiting than phosphate. See the
Redfield ratio.Phosphorus is a
limiting nutrient in many freshwater bodies. Oceans tend to have lower concentrations of phosphorus than freshwaters, but have more factors governing the limiting nutrient. Often, in marine ecosystems, the limiting nutrient is nitrogen rather than phosphorus. Phosphate is the most common form of phosphorus in the environment and is the only form of phosphorus that plants can use.
Plant metabolism Phosphorus abundance plays a role in regulating plant growth because phosphorus is part of important molecules including
nucleic acids,
phospholipids, and
ATP. Orthophosphate is the type of phosphorus that is easiest for plants to use, but orthophosphate concentrations in soils are usually low. In the direct uptake pathway, plants take up phosphate through root hairs, which can decrease phosphate concentrations in the
rhizosphere because phosphate does not renew as quickly as plants take it up. Up to 80% of the cellular phosphate is stored in
vacuoles, where plants can access it to maintain phosphorus supply for important functions. As clay minerals promote
biomineralization, the presence of bacteria and clay minerals resulted in calcium hydroxyapatite and calcite precipitates.
Goethite is one particularly common and important form of iron for these bonds. Phosphate may also adsorb to the edges of clay minerals including
koalinite,
montmorillonite, and
illite. Demand for phosphate fertilizers is increasing, likely increasing the impact on water bodies. Other sources of phosphate to the environment include detergent, sewage, and residential fertilizer use. Some countries have created laws regulating phosphate in detergents to reduce the phosphate pollution from detergents (see
Phosphates in detergent). Addition of high levels of phosphate to environments can have significant ecological consequences such as excessive plant growth. In the context of pollution, phosphates are one component of
total dissolved solids, a major indicator of water quality, but not all phosphorus is in a molecular form that algae can break down and consume. ==See also==