Environmental Impact and Health Effects of Potassium

With symbol K (from Latin kalium, “alkali”) and atomic number 19, Potassium is a chemically reactive and extremely soft metallic elements placed in group 1 of the periodic table. The element’s name comes from the English word potash, a potassium compound originally obtained by soaking wood ash in a pot of water and allowing the water to evaporate. Most potassium occurs in the Earth’s crust as minerals, such as feldspars and clays. Potassium is leached from these by weathering, which explains why there is quite a lot of this element in the sea (0.75 g/liter). Minerals mined for their potassium are pinkish and sylvite, carnallite and alunite. The main mining area used to be Germany, which had a monopoly of potassium before the First World War. Today most potassium minerals come from Canada, USA and Chile. The world production of potassium ores is about 50 million tonnes, and reserves are vast.

 

The metal is silvery white and can be cut with a knife but oxidizes rapidly in air and tarnishes within minutes, so it is generally stored under oil or grease. It is light enough to float onto water with which it reacts instantly to release hydrogen that burns with a lilac flame. Potassium exists in three natural isotopic forms, with mass numbers 39, 40, and 41. Potassium-40 is radioactive and has a half-life of 1.26 billion years. The most abundant isotope is potassium-39. Several radioactive isotopes have been artificially prepared. Potassium melts at about 63°C (about 145°F), boils at about 760°C (about 1400°F), and has a specific gravity of 0.86; the atomic weight of potassium is 39.098.The chemistry of potassium is almost entirely that of its ion, K+.

 

Potassium metal is prepared by the electrolysis of fused potassium hydroxide or of a mixture of potassium chloride and potassium fluoride. The metal oxidizes as soon as it is exposed to air and reacts violently with water, yielding potassium hydroxide and hydrogen gas. Potassium is found in nature in large quantities, ranking eighth in order of abundance of the elements in Earth’s crust, in various minerals. Potassium is a constituent of all plant and animal tissue as well as a vital constituent of fertile soil.

Potassium forms many compounds resembling corresponding sodium compounds, based on a valence of 1. A few of the element’s most important compounds are: Potassium bromide (KBr), a white solid formed by the reaction of potassium hydroxide and bromine; Potassium chromate (K2CrO4), a yellow crystalline solid, and potassium bichromate, or potassium dichromate (K2Cr2O7), a red crystalline solid, are powerful oxidizing agents used for many industrial purposes; Potassium iodide (KI), a white crystalline compound that is very soluble in water, is used in photography for preparing gelatin emulsions and in medicine for the treatment of rheumatism and over activity of the thyroid gland; Potassium nitrate (KNO3), a white solid prepared by fractional crystallization of sodium nitrate and potassium chloride solutions, is used in matches,  destructive materials, and fireworks, and in pickling meat(It occurs naturally as saltpeter); Potassium permanganate (KMnO4), a purple crystalline solid, is used as a disinfectant and germicide and as an oxidizing agent in many important chemical reactions; Potassium sulfate (K2SO4), a white crystalline solid, is an important potassium fertilizer and is also used in the preparation of potassium alum; and Potassium hydrogen tartrate (KHC4H4O6), commonly known as cream of tartar is a white solid used in baking powder and in medicine.

 

Most potassium goes into fertilizers (about 95 %) and the rest goes mainly into making potassium hydroxide (KOH), by the electrolysis of potassium chloride solution, and then converting this to potassium carbonate (K2CO3) which goes into glass manufacture, especially the glass used to make televisions. Potassium hydroxide is used to make liquid soaps and detergents. A little potassium chloride goes into pharmaceuticals, medical drips and saline injections. Other potassium salts are used in baking, photography and tanning leather, and to make iodize salts. In all cases it is the negative anion, not the potassium, which is the key to their use.

The term potash originally designated potassium carbonate, obtained by leaching wood ashes, but is now applied in general to a number of potassium compounds. Potassium carbonate (K2CO3), a white solid, also called potash or pearl ash, is obtained from the ash of wood or other burned plant materials, and by reacting potassium hydroxide with carbon dioxide. It is used in making glass and soft soap. Potassium chlorate (KClO3), called chlorate of potash, a white crystalline compound, is formed by the electrolysis of potassium chloride solution. It is a powerful oxidizing agent and is used in matches, fireworks, and explosives, as a disinfectant, and as a source of oxygen. Potassium chloride (KCl), a white crystalline compound commonly called chloride of potash or muriate of potash, is a common constituent of potassium salt minerals, from which it is obtained by volatilization. It is an important potassium fertilizer and is also used in making other potassium compounds. Potassium hydroxide (KOH), called caustic potash, a white solid that is dissolved by the moisture in the air, is prepared by the electrolysis of potassium chloride or by the reaction of potassium carbonate and calcium hydroxide; it is used in the manufacture of soap and is an important chemical reagent. It dissolves in less than its own weight of water, liberating heat and forming a strongly alkaline solution.

 

Potassium is a key plant element. Although it is soluble in water, little is lost from undisturbed soils because as it is released from dead plants and animal excrements, it quickly become strongly bound to clay particles, and it is retained ready to be readsorbed by the roots of other plants. Together with nitrogen and phosphorous, potassium is one of the essential macro minerals for plant survival.  Its presence is of great importance for soil health, plant growth and animal nutrition. Its primary function in the plant is its role in the maintenance of osmotic pressure and cell size, thereby influencing photosynthesis and energy production as well as stomatal opening and carbon dioxide supply, plant and translocation of nutrients. As such, the element is required in relatively large proportions by the growing plant. The consequences of low potassium levels are apparent in a variety of symptoms: restricted growth, reduced flowering, lower yields and lower quality produce. High water soluble levels of potassium cause damage to germinating seedlings inhibits the uptake of other minerals and reduces the quality of the crop.

 

Potassium can be found in vegetables, fruit, potatoes, meat, bread, milk and nuts. It plays an important role in the physical fluid system of humans and assists nerve functions. Potassium, as the ion K+, concentrate inside cells, and 95% of the body’s potassium is so located. When our kidneys are somehow malfunctioning an accumulation of potassium will consist. This can lead to disturbing heartbeats. Potassium can affect us when breathed in. Inhalation of dust or mists can irritate the eyes, nose, and throat, lungs with sneezing, coughing and sore throat. Higher exposures may cause a build up of fluid in the lungs, this can cause death. Skin and eye contact can cause severe burns leading to permanent damage.