WHAT IS PHOSPHORUS,

A COMPREHENSIVE GUIDE FOR PHOSPHORUSAND HOW IT AFFECTS OUR WORLD

Written by Tyler Huelsman

AND HOW IS IT MEASURED?

Measurement Parameter Series

Fondriest Environmental, Inc.

1415 Research Park Drive

Beavercreek, OH 45432

when your

demandsresearchquality data

Located in the Lower Great Lakes and Ohio River Valley region, Fondriest Environmental sells and services environmental monitoring products from industry leading suppliers such as YSI, Hach, Thermo Scientific, In-Situ, Turner Designs, SonTek, Vaisala, RM Young, NexSens, and many more...

The applications engineers and scientists at Fondriest Environmental specialize in designing and implementing real-time monitoring systems with data transmission via cellular, radio, landline phone, and satellite telemetry, as well as sharing data via the internet.

It is the company’s goal to supply equipment that provides high-quality data and years of service. Unlike many suppliers who carry every brand with every option, Fondriest seeks out vendors and products that meet stringent performance and quality standards. The company searches for advanced technologies that extend deployments and provide new methods of detection. The application engineers and scientists deploy many of the same products that they offer their customers.

Over the years, Fondriest Environmental has greatly expanded its product offering to provide environmental professionals with not only the finest measurement instrumentation, but also with a wide variety of equipment and accessories used extensively in day-to-day field work.

Fondriest’s commitment to customers and their projects ensure continued product support, resulting in long-lasting, value-added business relationships.

Phosphorus is an important component for all living organisms; it is responsible for many biological properties and functions, including the double helix shape of DNA as well as cellular respiration and metabolism. It is present in DNA, RNA, phosphoproteins, adenosine triphosphate (ATP), adenosine diphosphate (ADP), the esters of enzymes and vitamins, and bones. Phosphorus is the second most abundant nutrient in the human body, behind only calcium. It constitutes about one percent of a human’s body mass.

Fondriest Environmental application engineers are available to assist in configuring an ideal solution for your project needs. They can also help with training and technical support.

To reach them, please call (888) 426.2151 or email customercare@fondriest.com

CONTENTS

The Importance of Monitoring Phosphorus

What is Phosphorus?

The Phosphorus Cycle

How Phosphorus Enters the Envrionment

Effect of Phosphorus on the Environment and Human Health

How Phosphorus Concentration is Measured

Applications for Monitoring Phosphorus

Bibliography

Glossary

3

4

6

8

10

12

14

15

16

WHY PHOSPHORUS MATTERS

Phosphorus | 2

Due to the use of phosphorus in agriculture and its effects on life in ecosystems, it is also the subject of important regulations, management practices, and research programs. In fact, it is the most extensively studied element in freshwater.

Phosphorus is an important nutrient for the growth and metabolism of photosynthetic organisms. It is often a limiting factor in biological productivity, especially in aquatic ecosystems. Where there is little or no phosphorus in a lake or pond, there is also little or no life.

However, some freshwater systems have too much phosphorus. Excessive amounts lead to a phenomenon called eutrophication, a condition in which algae overrun the system and outcompete, poison, or asphyxiate other aquatic species.

Phosphorus is naturally occurring in land and is found in water in much smaller concentrations. Human influences over the years, however, have caused phosphorus concentrations to rise in many of the world’s bodies of water. These contributions have increased to such a point it is now necessary to monitor the phosphorus concentration in many water systems in order to prevent or minimize environmental consequences and keep the world’s limited freshwater resources usable..

THE IMPORTANCE of Monitoring Phosphorus

Phosphorus is an important catalyst for lighting matches.

Phosphorus | 3

Phosphorus is an important nutrient for the growth and metabolism of photosynthetic organisms.

Phosphorus is a chemical element with symbol, P, and atomic number 15. It is a nonmetal and is a solid in its elemental form at typical ranges of temperature and pressure. As an element, it generally exists as one of two main allotropes — white phosphorus or red phosphorus, but it can also exist as violet and black phosphorus.

White Phosphorus

White phosphorus molecules consist of four-atom tetrahedrons, in which each phosphorus atom is bonded with the three other atoms (Figure 1).

White phosphorus is the least stable of the phosphorus allotropes. When it is exposed to light or heat, it gradually changes into red phosphorus. White phosphorus is flammable and pyrophoric when it is exposed to the oxygen in air. When in contact with oxygen, it burns and glows green. This reaction forms crystalline phosphorus pentoxide, as shown:

P4 + 5O2 → P4O10

White phosphorus is only slightly soluble in water. It is often stored underwater in order to avoid contact with oxygen.

White phosphorus is commonly used in military munitions due to its volatility. It is most frequently employed in bombs, missiles, and mortars. Upon impact, phosphorus-based weapons explode into small pieces of burning phosphorus that are capable of producing lethal third degree burns. White phosphorus is also utilized to create smokescreens.

Phosphorus | 4

Figure 1.P4 Molecule

WHAT IS PHOSPHORUS?

Red Phosphorus

The red phosphorus allotrope is formed when white phosphorus is exposed to high temperatures or sunlight over time. The rate of change depends on the quantity of heat or sunlight applied. The physical properties of the phosphorus change as it shifts from white to red phosphorus. The P4 molecules break down and form amorphous chains of red phosphorus (Figure 2).

Red phosphorus is actually an intermediate phase between white and violet phosphorus and is not its own distinct allotrope. Therefore it has a wide range of properties. The structure of red phosphorus is more stable than that of white phosphorus. Red phosphorus does not self-ignite in air below 260 ºC, but it is still flammable.

Red phosphorus is used commercially in matches, strike plates for matches, fertilizers, pesticides, rat poison, and semiconductors.

Violet and Black Phosphorus

Violet and black phosphorus are thermodynamically stable allotropes. They are rare forms of phosphorus due to the specific conditions required for their creation.

Violet phosphorus is a crystalline solid that results from exposing red phosphorus to temperatures above 500 ºC for several days.

Black phosphorus is obtained by subjecting white phosphorus to temperatures of around 500 ºC and extremely high pressures (1200 atmospheres). It is flaky, resembling graphite in texture, and is the least reactive form of phosphorus.

Phosphorus | 5

Figure 2. Red Phosphorus Structure

Phosphorus | 6

Phosphorus is the least abundant of the major nutrients in water, behind carbon, nitrogen, hydrogen, oxygen, and potassium. A low concentration of phosphorus in water can limit biological productivity. The unique relationship between phosphorus and aquatic ecosystems has made it the subject of many ecological studies.

Inorganic Phosphorus

Phosphorus rarely exists in nature in its elemental form. It is usually found in either inorganic or organic phosphorus compounds in water, rock, soil, or living organisms.

The phosphorus cycle begins with inorganic phosphorus, which on average makes up less than 10% of the total phosphorus found in freshwater systems. It is cycled quickly in places where it is consumed by organisms. Orthophosphate (PO4

3-) is the most significant form of inorganic phosphorus found in water. Polyphosphates, more complex inorganic compounds, are also present in water at lower concentrations.

Unlike other natural cycles, such as those of nitrogen and carbon, the phosphorus cycle has no gaseous phase.

Phosphorus does not exist as a gas in the atmosphere. Instead, phosphorus in the form of orthophosphate is weathered from rocks and sediment, particularly apatite, by rain and surface runoff. Over long periods of time, phosphate rock is deposited at the bottom of water bodies through sedimentation. It is also deposited into the soil where it is used by crops and other terrestrial plants.

Organic Phosphorus

Photosynthetic organisms synthesize ionized forms of phosphates and other nutrients in the water or soil to create various forms of organic phosphorus, which is an essential component of life. Nucleotides, such as ADP and ATP, drive the cellular transfer of chemical energy used for metabolism. Nucleotides also make up part of the structure of DNA and RNA.

Animals obtain organic phosphorus by eating plants and other animals. Decomposing plants and animals release organic phosphorus back into the soil or water. Organic phosphorus is also released into the environment through animal waste.

Organic phosphorus is found in various forms in water, including soluble and suspended (sestonic) forms. Soluble organic phosphorus also often includes phosphorus in a colloidal state. Organic phosphorus makes up about 90% of the phosphorus in freshwater systems.

THE PHOSPHORUS CYCLE

The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and phosphorus-based compounds are usually solids at the typical ranges of temperature and pressure found on Earth.

Phosphorus | 7

THE PHOSPHORUS CYCLE

Feeding byheterotrophs

Cell respiration

Phosphate excreted

Fertilizer

Agriculture

Mining of phosphate rock

Phosphate in soil

Phosphate dissolved in water

Algaephytoplankton

Sedimentation formation of phosphate rock

Leaching of fertilizer

Millions of years

Phosphate taken up by plants. Fixed into organic phosphate in plant biomass.

Phosphorus | 8

Phosphorus is naturally occurring and is conserved in the environment in a multitude of substances. Along with carbon dioxide, water, and sunlight, plants require phosphorus to grow. Humans also need different forms of phosphorus for various biological purposes, including bone structure and retaining homeostasis.

Natural sources of phosphorus include several minerals found in rocks and soil. Exposure to rain or snowmelt causes phosphate ions from these minerals to leach into nearby water sources. Considering the low solubility of phosphorus, this is generally a slow process.

Phosphorus is not always replenished in the soil by natural means. Over-farming and aggressive agricultural practices often deplete phosphorus in soil. For the past century, the primary solution to this has been to apply synthetic fertilizers liberally to agricultural land in order to maximize crop production.

The use of phosphorus in fertilizer has revolutionized the farming industry. In fact, the proliferation of modern agricultural practices including fertilization after World War II is often referred to as the “Green Revolution.” Despite the environmentally friendly connotations now associated with the descriptor “green,” the impact of over-fertilization has been devastating to the environment.

Phosphate Mining

Inorganic phosphate is mined from large phosphate rock deposits for industrial use. Of the phosphate mined, 84% to 90% is used for fertilizer production. The remainder is used in the chemical, light, and defense industries.

Phosphate mining has occurred for more than 100 years. Phosphate rock deposits are found on the surface, so phosphate is obtained primarily through surface mining. The current method of mining uses diesel or electric-powered dragline excavators to mine the phosphate

rock from the Earth in large proportions. A single dragline excavator can mine about 135,000 tons of phosphate rock per month. In 2003, the phosphate industry in Florida, the United States’ leading producer of the chemical, mined 22.8 million metric tons of phosphate rock.

HOW PHOSPHORUS Enters the Environment

Despite the environmentally friendly connotations now associated with the descriptor “green,” the impact of over-fertilization has been devastating to the environment.

Phosphate mining on the island of Nauru

Phosphorus | 9

Phosphate Processing

Phosphate rock is processed in beneficiation plants near phosphate mines. It is turned into slurry by high-pressure water guns on site then pumped into the plants where it is processed and used in fertilizer and other applications.

The phosphate rock slurry is first separated from sand and clay. The remaining substance is calcium phosphate (Ca3(PO4)2). The calcium phosphate is then mixed with sulfuric acid (H2SO4) to form phosphoric acid (H3PO4) and calcium sulfate dihydrate (CaSO4•2H2O), according to the following equation:

Ca3(PO4)2 + 3H2SO4 + 2H2O → 2H3PO4 + 3CaSO4 • 2H2O

Phosphoric acid is mixed with other substances to produce the phosphate compounds used in industry. Ammonium phosphate ((NH4)3PO4), which is used as an ingredient in fertilizer, is the most common of these compounds.

Ammonium Phosphate Fertilizer

Ammonium phosphate is a synthetic fertilizer that is used heavily in agriculture. Farmers apply it to their fields, where it provides crops with the nutrients phosphorus and nitrogen.

Ammonium phosphate and other phosphorus-based fertilizers help achieve optimal crop yield and ensure against crop failure.

However, farmers often overuse fertilizer and apply many times more than what is necessary, because fertilizer is cheap compared to the price of losing crops. Leftover phosphorus slowly leaches from the soil through surface runoff and rain. This water flows into and contaminates ponds, streams, rivers, lakes, and other surface waters. Phosphorus contamination alters the natural properties of each aquatic ecosystem through which it passes.

Catalyst(V2O5)

Water

Fertilizer

NH3

Sulfur SO2 SO3

H2SO4

H3PO4CaSO4 • 2H2O

Raw Ore

SlurryCa3(PO4)2

Figure 3. Phosphorus Processing

Phosphogypsum

Calcium sulfate dihydrate is called gypsum, a soft mineral that is abundant in nature. The gypsum that is the byproduct of producing phosphoric acid is known as phosphogypsum. Phosphogypsum is more radioactive than naturally occurring gypsum because radium found in mined phosphate rock associates with the calcium sulfate after the production of phosphoric acid.

For every ton of phosphoric acid produced, five tons of phosphogypsum are produced. The use of phosphogypsum in industry is prohibited by the EPA unless it has an average concentration of less than 10 picocuries per gram (pCi/g) radium. Because most of Florida’s phosphogypsum exceeds this limit, the state’s phosphate industry generally cannot use its phosphogypsum in consumer products. The phosphogypsum is instead piled in massive stacks (Figure 4). There are currently over one billion tons of phosphogypsum in twenty-five stacks in Florida, and approximately 30 million tons are added every year. The phosphogypsum stacks pose the threat of becoming permanent fixtures of the land, taking up more space every year.

Eutrophication

Excessive levels of phosphorus are detrimental to aquatic ecosystems. Surface runoff leaches phosphorus from agricultural land and into streams, rivers, and other water systems. This land tends to be over-fertilized with either synthetic fertilizers like ammonium phosphate or natural fertilizers like hog manure that are high in phosphorus. When phosphorus concentrations rise significantly above natural levels in the water, a phenomenon called eutrophication occurs. It is estimated 48% of lakes in North America are eutrophic.

Eutrophication occurs in water with abnormally large concentrations of nutrients, especially phosphorus and nitrogen. The presence of excessive nutrients causes a rapid increase in primary production, meaning phytoplankton and bacteria grow in large proportions.

Algal blooms are common in eutrophic waters. When phosphorus levels are too high, algae grow quickly. Slow moving, green-water lakes and ponds are especially susceptible to algal blooms.

Some varieties of algae can even produce toxins that are dangerous to aquatic organisms, wildlife, and humans. Blue-green algae, which are actually bacteria called cyanobacteria, are notorious for releasing harmful toxins in aquatic environments.

Symptoms of a eutrophic water system include: • Increased amount of algae/phytoplankton • Toxic varieties of algae/phytoplankton • Decrease in dissolved oxygen • Increased number of fish kills • Decrease in edibility of fish and shellfish • Decrease in aesthetic value of water • Undesirable color and smell • Difficulty in water treatment

Phosphorus | 10

EFFECT OF PHOSPHORUS on the Environment and Human Health

Figure 4. Phosphogypsum Stack in Fort Meade, Florida

Phosphorus | 11

Dead Zones

In addition to releasing toxins, algal blooms are responsible for large fluctuations in the dissolved oxygen content of water. During the day, algae photosynthesize, consuming carbon dioxide and releasing oxygen into the water. However, during the night, algae respire, consuming oxygen and releasing carbon dioxide. In this way, algal blooms can create hypoxic conditions at night. Additionally, when algae decay, bacteria uses dissolved oxygen in the water as part of the bacterial decomposition process.

Fish and other aquatic species cannot live in an aquatic environment with low concentrations of dissolved oxygen. When conditions are hypoxic — less than 30% dissolved oxygen saturation — aquatic species can suffocate and die en masse. Areas that cannot sustain life because they are hypoxic are known as “dead zones.”

Phosphorus was a significant contributor to dead zones in Lake Erie and the Gulf of Mexico. In the 1970s, Lake Erie was completely anoxic (without oxygen) and was declared a “dead lake.” Because of this, controls were enacted on the nutrient loading that was contributing to algal blooms in the lake. The EPA also monitored the dissolved oxygen content of the lake to measure any changes. In the 1980s, the lake’s dissolved oxygen concentration was on the rise, and the dead zones were disappearing. In recent years, however, the status of the lake’s dead zones worsen, and dissolved oxygen levels are down.

A similar situation is occurring in the Gulf of Mexico, where nutrient loading from the Mississippi River has caused eutrophic conditions and the creation of dead zones. First noticed in the 1970s, the dead zones in the Gulf of Mexico now make up about 10,000 square miles, and they continue to increase in size.

Phosphorus and Human Health

Organophosphates are frequently used in pesticides. Organophosphates such as these are powerful nerve agents that disrupt the action of the acetylcholinesterase enzymes that allow neurotransmitters to function. Exposure to organophosphate nerve agents causes pupil contraction, salivation, lacrimation, involuntary urination and defecation, vomiting, convulsions, and eventually death by asphyxiation as control is lost over respiratory muscles.

Despite the alarming and potentially deadly effects of organophosphate, these pesticides have little effect on humans when used properly. However, prolonged exposure can cause organophosphate poisoning. Organophosphate pesticides are widely used as poisons and as a method for suicide. Production of chemical weapons that include organophosphates was outlawed in the Chemical Weapons Convention of 1993.

Phosphorus necrosis of the jaw, also known as “phossy jaw,” is a disease caused by exposure to white phosphorus and its vapors. It most commonly occurs in people who regularly work around white phosphorus. Sufferers of this condition have phosphorus deposited in their jaws that can cause painful toothaches and swelling of the gums.

Inorganic phosphate, on the other hand, is not considered harmful for human consumption. In fact, it is added to drinking water in some places to lower its pH and prevent corrosion in pipelines.

Phosphorus necrosis of the jaw, also known as “phossy jaw,” is a disease caused by exposure to white phosphorus and its vapors.

Phosphorus | 12

There are several processes for testing phosphorus concentration in water. The type of phosphorus compound being measured dictates what method is appropriate. Phosphorus in a water sample is broken into three components for analytical purposes: soluble reactive phosphorus (SRP), soluble unreactive (or soluble organic) phosphorus (SUP), and particulate phosphorus (PP). Together, these three make up total phosphorus (TP) concentration.

The analysis of a phosphorus sample involves two steps: the conversion of the phosphorus compound into dissolved orthophosphate (sample preparation), and the colorimetric determination of the dissolved orthophosphate in the sample (measurement). The concentrations of the different types of phosphorus compounds mentioned above can be found using the procedure shown:

Filtration

Soluble forms of phosphorus are separated from suspended forms through filtration in the first step of sample preparation. A 0.45μm pore diameter membrane is the established standard for making a thorough separation. However, it is recognized that this method of filtration does not necessarily produce complete separation. Some colloidal forms of phosphorus can pass through this filter size.

Glass fiber filters can replace or supplement membrane filters. Glass filters transmit more suspended phosphorus than membrane filters, which can cause the soluble phosphorus measurement to be inflated. The benefit of glass filters is their low cost compared to membrane filters. Glass fiber filters are also convenient due to their frequent use in other water quality tests for suspended solids.

The concentration of soluble reactive phosphorus can be determined using filtration alone. Soluble reactive phosphorus is measured as the orthophosphate concentration in the filtered sample. In order to find the concentration of all soluble phosphorus, and subsequently soluble unreactive phosphorus, the filtered sample must be digested.

Digestion

Digestion is the second step in sample preparation. It is a technique used to oxidize all present forms of phosphorus to release measureable orthophosphate. Various acids have been used as oxidizers for digestion, but none of them are completely effective.

Popular methods for digestion include perchloric acid, sulfuric acid-nitric acid, and persulfate digestion. The perchloric acid method is the most difficult and time consuming and is therefore only recommended for difficult samples. The nitric acid-sulfuric acid method is viable for most samples. The persulfate oxidation method is the simplest, but it is also the most suspect to error.

By digesting a filtered sample, one can determine total soluble phosphorus concentration, while digesting an unfiltered sample reveals total phosphorus concentration. The difference between total soluble phosphorus concentration and soluble reactive phosphorus concentration is soluble organic phosphorus concentration, and the difference between total phosphorus concentration and total soluble phosphorus concentration is particulate phosphorus concentration.

HOW PHOSPHORUS CONCENTRATION is Measured

Whole Water Sample

SolubleReactive P Soluble

Unreactive P

TotalP

Filter

DigestDigest

Figure 5. Phosphorus Sample Preparation

Phosphorus | 13

Orthophosphate concentration in a sample is determined by colorimetry. There are a few colorimetric methods, depending on the range in concentration being measured. The vanadomolybdophosphoric acid method is suitable for the range of 1 to 20 mg P/L. The stannous chloride and ascorbic acid methods are more appropriate for the range of 0.01 to 6 mg P/L, at which greater sensitivity is needed for precision.

The vanadomolybdophosphoric acid method is based on the reaction of ammonium molybdate and orthophosphate in an acid medium to form molybdophosphoric acid. When vanadium is introduced to the sample, vanadomolybdophosphoric acid forms. Vanadomolybdophosphoric acid is yellow in color. The intensity of the yellow is proportional to the concentration of orthophosphate in the sample.

The stannous chloride method is also based on the formation of molybdophosphoric acid. Once formed, the molybdophosphoric acid is reduced by stannous chloride to form molybdenum blue. The intensity of the blue is proportional to the concentration of orthophosphate in the sample.

The ascorbic acid method is based on the reaction of ammonium molybdate and potassium antimonyl tartrate with orthophosphate in an acid medium to form phosphomolybdic acid. Once formed, the phosphomolybdic acid is reduced by ascorbic acid to form molybdenum blue. The intensity of the blue is proportional to the concentration of orthophosphate in the sample.

By testing the colored samples in a spectrophotometer at a specific wavelength, a quantitative value for the absorbance of the sample is measured. The absorbance is then compared to a standard calibration to determine the concentration of orthophosphate in the sample.

Colorimetry

Orthophosphate concentration can be measured by colorimetry, such as with a Hach Pocket Colorimeter.

Agricultural Runoff

Fields utilized for agricultural purposes are typical sources of phosphorus contamination. These are identified as nonpoint sources because phosphorus is not added directly to the water; rather, it leaches through the soil.

Nonpoint sources can be difficult to monitor directly. Alternatively, freshwater systems in the vicinity of farmland are often monitored in order to test the impact agriculture has on local surface water. Phosphorus monitoring is important in order to gauge the success of efforts to control nonpoint pollution levels in the surrounding watershed.

Ecosystem Preservation and Reclamation

Various projects for the preservation and reclamation of freshwater systems use phosphorus monitoring extensively. A prime example of an ecosystem reclamation project that requires phosphorus monitoring is the Comprehensive Everglades Restoration Plan. The CERP involves monitoring several Florida water bodies including Lake Okeechobee, the Caloosahatchee River,

and St. Lucie Estuary, and other sources of phosphorus contamination to the Everglades. The CERP also involves the construction of more than 36,000 acres of stormwater treatment areas that filter thousands of tons of phosphorus out of Everglades waters. Phosphorus monitoring is important in order to measure the progress being made in reclamation efforts.

Load Monitoring and Wastewater Effluent Standards

The EPA enforces water quality standards regarding phosphorus contamination in a number of ways. The agency commonly implements Total Maximum Daily Loads on affected freshwater systems. In order for these systems to meet the TMDL, the water is monitored at a number of sites within the system to help identify the source or sources of the contaminant. When the source is discovered and work begins to alleviate the contaminant load, monitoring efforts continue in order to measure progress.

The EPA also limits phosphorus contamination by enforcing federal regulations on wastewater from industrial facilities. This is similar to a TMDL, except it regulates point source rather than nonpoint source pollution. For example, the EPA Code of Federal Regulations sets the maximum output of phosphorus in phosphate manufacturing effluent at 105 mg/L on any day and an average of 35 mg/L for a thirty day period. Manufacturers are obligated to monitor their effluent to determine whether they are within these regulations.

Research

Research on the effects of phosphorus in lakes and other freshwater systems is an ongoing process that requires constant monitoring of phosphorus levels. Studies on the relationship of phosphorus and the ecology of freshwater systems is of practical importance. Data and models produced from this research can help predict the changes in water quality of a system based on the concentration of phosphorus. It also provides useful information for current and future water reclamation and preservation projects.

APPLICATIONS for Monitoring Phosphorus

Phosphorus | 14

Averbuch-Pouchot, M.T., A. Durif. 1996. Topics in Phosphate Chemistry. World Scientific.

Carlson, R.E., and J. Simpson. 1996. A Coordinator’s Guide to Volunteer Lake Monitoring Methods. North American Lake Management Society.

Gain, W. Scott. 1997. An Optimized Network for Phosphorus Load Monitoring for Lake Okeechobee, Florida. U.S. Geological Survey.

Greenberg, Arnold, Lenore Clesceri, and Andrew Eaton. 1992. Standard Methods for the Examination of Water and Wastewater, 18th Edition. American Public Health Association.

Wetzel, Robert. 2001. Limnology: Lake and River Ecosystems, 3rd Edition. Academic Press, San Diego, CA.

Zhang, Patrick. Mining and Beneficiation. Florida Institute of Phosphate Research. n.d. Web. <http://www.fipr.state.fl.us/>

IMAGE CREDITS

Phosphate mining in Nauru photo (page 8) by Jacky Ghossein.

Phosphogypsum stack photo (page 10) by Harvey Henkelmann.

BIBLIOGRAPHY

Phosphorus | 15

Absorbance: The measureable quantity of light absorbed by a substance.

Allotrope: One of multiple existing structural forms of an element. Different allotropes of an element have distinct properties.

Apatite: A type of mineral that contains phosphate and is often referred to as phosphate rock or phosphate ore. It is mined in large quantities for phosphate that is used in industry and agriculture.

Beneficiation: The process by which mined ore is separated into a desired product and waste material.

Cyanobacteria: Photosynthetic bacteria commonly known as blue-green algae. It is found in both aquatic environments and in soil.

Digestion: The process by which organic material is broken down into inorganic compounds.

Dissolved Oxygen: The concentration of oxygen gas dissolved in water. Commonly abbreviated as DO.

Eutrophication: The rapid growth of algae and other ecologically damaging effects that result from large concentrations of dissolved nutrients entering an aquatic ecosystem.

Green Revolution: The development and spread of agricultural technology throughout the globe beginning in the 1940s. These technologies include mechanization, irrigation, crop rotation, and the application of synthetic fertilizers and pesticides.

Homeostasis: The property of a living organism maintaining constant stable internal conditions, such as body temperature and blood constitution.

Hypoxia: The quality of an aquatic system with a depleted concentration of dissolved oxygen, causing the asphyxiation of many aquatic organisms.

Nucleotide: A molecule that includes a nitrogenous base and one or more phosphate groups. Nucleotides make up DNA and RNA, as well as the ATP and ADP that are responsible metabolism

Organophosphate: An ester of phosphate that is often used in herbicides and insecticides. It is also a powerful nerve agent.

Orthophosphate: The most basic form of inorganic phosphate, PO4

3-.

Polyphosphate: Phosphate polymer. It is used in laundry detergents and water softeners, among other applications.

Phosphogypsum: A substantial byproduct of phosphoric acid production in phosphate manufacturing. It tends to be more radioactive than naturally occurring gypsum.

Pyrophoric: The quality of a substance that spontaneously ignites when exposed to air.

GLOSSARY

Phosphorus | 16

Fondriest Environmental, Inc.1415 Research Park DriveBeavercreek, OH 45432

when your

demandsresearchquality data