Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature , but synthetic latices are common as well.
112-478: Sodium chloride / ˌ s oʊ d i ə m ˈ k l ɔːr aɪ d / , commonly known as edible salt , is an ionic compound with the chemical formula NaCl , representing a 1:1 ratio of sodium and chlorine ions. It is transparent or translucent, brittle, hygroscopic , and occurs as the mineral halite . In its edible form, it is commonly used as a condiment and food preservative . Large quantities of sodium chloride are used in many industrial processes, and it
224-625: A Bresle test . Salinization (increasing salinity, aka freshwater salinization syndrome ) and subsequent increased metal leaching is an ongoing problem throughout North America and European fresh waterways. In highway de-icing, salt has been associated with corrosion of bridge decks, motor vehicles, reinforcement bar and wire, and unprotected steel structures used in road construction. Surface runoff , vehicle spraying, and windblown salt also affect soil, roadside vegetation, and local surface water and groundwater supplies. Although evidence of environmental loading of salt has been found during peak usage,
336-432: A face-centered cubic (fcc) lattice with a two-atom basis or as two interpenetrating face centered cubic lattices. The first atom is located at each lattice point, and the second atom is located halfway between lattice points along the fcc unit cell edge. Solid sodium chloride has a melting point of 801 °C and liquid sodium chloride boils at 1465 °C. Atomic-resolution real-time video imaging allows visualization of
448-424: A "second skin" effect. Synthetic latices are used in coatings (e.g., latex paint) and glues because they solidify by coalescence of the polymer particles as the water evaporates. These synthetic latices therefore can form films without releasing potentially toxic organic solvents in the environment. Other uses include cement additives and to conceal information on scratchcards . Latex, usually styrene -based,
560-439: A better protection to the plant from enemies than all the thorns, prickles, or hairs that could be provided. In this plant, so copious and so distasteful has the sap become that it serves a most important purpose in its economy. Evidence showing this defense function include the finding that slugs will eat leaves drained of their latex but not intact ones, that many insects sever the veins carrying latex before they feed, and that
672-406: A branching system extending throughout the plant. In many euphorbs , the entire structure is made from a single cell – this type of system is known as a non-articulated laticifer , to distinguish it from the multi-cellular structures discussed above. In the mature plant, the entire laticiferous system is descended from a single cell or group of cells present in the embryo . The laticiferous system
784-438: A fertilizer, applying a moderate concentration helps avoid potential toxicity; typically, 1–3 grams (0.035–0.106 oz) per liter is considered safe and effective for most plants. Sodium chloride is one of the largest volume inorganic raw materials. It is a feedstock in the production of caustic soda and chlorine . These are used in the manufacture of PVC , paper pulp and many other inorganic and organic compounds. Salt
896-443: A healthy level of sodium intake of between 4 and 5 grams (equivalent to 10-13 g salt) a day. One of the two most prominent dietary risks for disability in the world are diets high in sodium. Only a small percentage of the salt manufactured in the world is used in food. The remainder is used in agriculture, water treatment, chemical production, de-icing, and other industrial use cases. In the practice of watering plants with salt as
1008-422: A high sodium content and fill a similar role to table salt in western cultures. They are most often used for cooking rather than as table condiments. Human salt taste is detected by sodium taste receptors present in taste bud cells on the tongue. Human sensory taste testing studies have shown that proteolyzed forms of epithelial sodium channel (ENaC) function as the human salt taste receptor. Table salt
1120-405: A latex allergy. Latex-fruit syndrome Many people with latex allergy also experience allergic reactions to certain fruits. This association has led to research regarding latex-fruit syndrome (LFS). This is a phenomenon characterized by cross-reactivity between natural latex rubber allergens and certain fruit allergens, leading to allergic reactions in sensitized individuals. It was described for
1232-527: A lower-allergen substitute. Additionally, chemical processes may be employed to reduce the amount of antigenic protein in Hevea latex, yielding alternative materials such as Vytex Natural Rubber Latex which provide significantly reduced exposure to latex allergens. About half of people with spina bifida are also allergic to natural latex rubber. People who have had multiple surgeries and who have had prolonged exposure to natural latex are also more susceptible to
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#17328445971971344-632: A major source of food spoilage. Even though more effective desiccants are available, few are safe for humans to ingest. Many microorganisms cannot live in a salty environment: water is drawn out of their cells by osmosis . For this reason salt is used to preserve some foods, such as bacon, fish, or cabbage. In many dairy industries, salt is added to cheese as a color-, fermentation-, and texture-control agent. The dairy subsector includes companies that manufacture creamery butter, condensed and evaporated milk, frozen desserts, ice cream, natural and processed cheese, and specialty dairy products. In canning, salt
1456-510: A metaphor. Uses include the tale of how Lot's wife is turned into a pillar of salt when looking back at the cities of Sodom and Gomorrah as they are destroyed. In the New Testament , Jesus refers to his followers as the " salt of the earth ". In Aztec mythology, Huixtocihuatl was a fertility goddess who presided over salt and salt water. Salt is an auspicious substance in Hinduism and
1568-461: A mildly "fishy" or "sea-air" odour, the latter from organobromine compounds . Sediments, the proportion of which varies with the source, give the salt a dull grey appearance. Since taste and aroma compounds are often detectable by humans in minute concentrations, sea salt may have a more complex flavour than pure sodium chloride when sprinkled on top of food. When salt is added during cooking however, these flavours would likely be overwhelmed by those of
1680-460: A preservative, salt inhibits the growth of bacteria. Salt acts as a binder in sausages to form a binding gel made up of meat, fat, and moisture. Salt also acts as a flavor enhancer and as a tenderizer . It is used as a cheap and safe desiccant because of its hygroscopic properties, making salting an effective method of food preservation historically; the salt draws water out of bacteria through osmotic pressure , keeping it from reproducing,
1792-453: A problem in any coating application, because trapped salts cause great problems in adhesion. Naval authorities and ship builders monitor the salt concentrations on surfaces during construction. Maximal salt concentrations on surfaces are dependent on the authority and application. The IMO regulation is mostly used and sets salt levels to a maximum of 50 mg/m soluble salts measured as sodium chloride. These measurements are done by means of
1904-566: A product of an emulsion , mini-emulsion, micro-emulsion, or dispersion polymerization . The cells ( laticifers ) in which latex is found make up the laticiferous system, which can form in two very different ways. In many plants, the laticiferous system is formed from rows of cells laid down in the meristem of the stem or root . The cell walls between these cells are dissolved so that continuous tubes, called latex vessels, are formed. Since these vessels are made of many cells, they are known as articulated laticifers . This method of formation
2016-522: A salt spring in Lunca , Neamț County , Romania. Evidence indicates that Neolithic people of the Precucuteni Culture were boiling the salt-laden spring water through the process of briquetage to extract salt as far back as 6050 BC. The salt extracted from this operation may have directly correlated with the rapid growth of this society's population soon after production began. The harvest of salt from
2128-504: A salty bread or to add salt to the bread if this bread is unsalted when doing Kiddush for Shabbat . It is customary to spread some salt over the bread or to dip the bread in a little salt when passing the bread around the table after the Kiddush. To preserve the covenant between their people and God, Jews dip the Sabbath bread in salt. Salt plays a role within different Christian traditions. It
2240-426: A scrubbing agent when combined with oil. Salt is present in most foods , but in naturally occurring foodstuffs such as meats, vegetables and fruit, it is present in very small quantities. It is often added to processed foods (such as canned foods and especially salted foods , pickled foods , and snack foods or other convenience foods ), where it functions as both a preservative and a flavouring . Dairy salt
2352-931: A sodium chloride solution remains ≈7 due to the extremely weak basicity of the Cl ion, which is the conjugate base of the strong acid HCl. In other words, NaCl has no effect on system pH in diluted solutions where the effects of ionic strength and activity coefficients are negligible. Common salt has a 1:1 molar ratio of sodium and chlorine. In 2013, compounds of sodium and chloride of different stoichiometries have been discovered; five new compounds were predicted (e.g., Na 3 Cl, Na 2 Cl, Na 3 Cl 2 , NaCl 3 , and NaCl 7 ). The existence of some of them has been experimentally confirmed at high pressures and other conditions: cubic and orthorhombic NaCl 3 , two-dimensional metallic tetragonal Na 3 Cl and exotic hexagonal NaCl. This indicates that compounds violating chemical intuition are possible, in simple systems under non-ambient conditions. Salt
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#17328445971972464-505: A virtually inexhaustible source of salt, and this abundance of supply means that reserves have not been calculated. The evaporation of seawater is the production method of choice in marine countries with high evaporation and low precipitation rates. Salt evaporation ponds are filled from the ocean and salt crystals can be harvested as the water dries up. Sometimes these ponds have vivid colours, as some species of algae and other micro-organisms thrive in conditions of high salinity. Away from
2576-439: A yellow colour. Folic acid helps prevent neural tube defects and anaemia, which affect young mothers, especially in developing countries. A lack of fluoride in the diet is the cause of a greatly increased incidence of dental caries . Fluoride salts can be added to table salt with the goal of reducing tooth decay, especially in countries that have not benefited from fluoridated toothpastes and fluoridated water. The practice
2688-537: Is a complex emulsion that coagulates on exposure to air, consisting of proteins , alkaloids , starches , sugars , oils , tannins , resins , and gums . It is usually exuded after tissue injury. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Since the 17th century, latex has been used as a term for the fluid substance in plants, deriving from the Latin word for "liquid". It serves mainly as defense against herbivorous insects . Latex
2800-434: Is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses . Another major application of sodium chloride is deicing of roadways in sub-freezing weather. In addition to the many familiar domestic uses of salt, more dominant applications of the approximately 250 million tonnes per year production (2008 data) include chemicals and de-icing. Salt is used, directly or indirectly, in
2912-681: Is about 10 g per day, and it is higher than that in many countries in Eastern Europe and Asia. The high level of sodium in many processed foods has a major impact on the total amount consumed. In the United States, 75% of the sodium eaten comes from processed and restaurant foods, 11% from cooking and table use and the rest from what is found naturally in foodstuffs. Because consuming too much sodium increases risk of cardiovascular diseases , health organizations generally recommend that people reduce their dietary intake of salt. High sodium intake
3024-489: Is actively moved to the area of injury; in the case of Cryptostegia grandiflora , latex more than 70 cm from the site of injury is mobilized. The large hydrostatic pressure in this vine enables an extremely high flow rate of latex. In a 1935 report the botanist Catherine M. Bangham observed that "piercing the fruit stalk of Cryptostegia grandiflora produced a jet of latex over a meter long, and maintained [this jet] for several seconds." The clotting property of latex
3136-467: Is added to food, either by the food producer or by the consumer, as a flavor enhancer, preservative, binder, fermentation -control additive, texture-control agent, and color developer. The salt consumption in the food industry is subdivided, in descending order of consumption, into other food processing, meat packers, canning , baking, dairy, and grain mill products. Salt is added to promote color development in bacon, ham and other processed meat products. As
3248-530: Is added to secure the soil and to provide firmness to the foundation on which highways are built. The salt acts to minimize the effects of shifting caused in the subsurface by changes in humidity and traffic load. Hard water contains calcium and magnesium ions that interfere with action of soap and contribute to the buildup of a scale or film of alkaline mineral deposits in household and industrial equipment and pipes. Commercial and residential water-softening units use ion-exchange resins to remove ions that cause
3360-483: Is also a major source. China is the world's main supplier of salt. In 2017, world production was estimated at 280 million tonnes , the top five producers (in million tonnes) being China (68.0), United States (43.0), India (26.0), Germany (13.0), and Canada (13.0). Salt is also a byproduct of potassium mining. Salt#Edible salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it
3472-476: Is also used a seasoning agent, e.g. in potato chips, pretzels , and cat and dog food. Sodium chloride is used in veterinary medicine as emesis -causing agent. It is given as warm saturated solution. Emesis can also be caused by pharyngeal placement of small amount of plain salt or salt crystals. For watering plants to use sodium chloride ( NaCl ) as a fertilizer, moderate concentration is used to avoid potential toxicity: 1–3 grams (0.035–0.106 oz) per liter
Sodium chloride - Misplaced Pages Continue
3584-465: Is also used in immunoassays . Some people only experience a mild allergy when exposed to latex, with symptoms such as eczema , contact dermatitis , or developing a rash . Others have a serious latex allergy , and exposure to latex products such as latex gloves can cause anaphylactic shock . Guayule latex has only 2% of the levels of protein found in Hevea latices, and it is being researched as
3696-447: Is an important component of drilling fluids in well drilling. It is used to flocculate and increase the density of the drilling fluid to overcome high downwell gas pressures. Whenever a drill hits a salt formation, salt is added to the drilling fluid to saturate the solution in order to minimize the dissolution within the salt stratum. Salt is also used to increase the curing of concrete in cemented casings. In textiles and dyeing, salt
3808-469: Is an important micronutrient for humans, and a deficiency of the element can cause lowered production of thyroxine ( hypothyroidism ) and enlargement of the thyroid gland ( endemic goitre ) in adults or cretinism in children. Iodized salt has been used to correct these conditions since 1924 and consists of table salt mixed with a minute amount of potassium iodide , sodium iodide , or sodium iodate . A small amount of dextrose may be added to stabilize
3920-561: Is associated with a greater risk of stroke , total cardiovascular disease and kidney disease . A reduction in sodium intake by 1,000 mg per day may reduce cardiovascular disease by about 30 percent. In adults and children with no acute illness, a decrease in the intake of sodium from the typical high levels reduces blood pressure. A low sodium diet results in a greater improvement in blood pressure in people with hypertension . The World Health Organization recommends that adults should consume less than 2,000 mg of sodium (which
4032-420: Is contained in 5 g of salt) per day. Guidelines by the United States recommend that people with hypertension, African Americans, and middle-aged and older adults should limit consumption to no more than 1,500 mg of sodium per day and meet the potassium recommendation of 4,700 mg/day with a healthy diet of fruits and vegetables. While reduction of sodium intake to less than 2,300 mg per day
4144-419: Is dug out by the room and pillar method, where about half the material is left in place to support the upper levels. Extraction of Himalayan salt is expected to last 350 years at the present rate of extraction of around 385,000 tons per annum.The mine is also a major tourist attraction, receiving around a quarter of a million visitors a year. Salt has long held an important place in religion and culture. At
4256-693: Is either beneficial or harmful. Evidence shows a more complicated relationship between salt and cardiovascular disease. "The association between sodium consumption and cardiovascular disease or mortality is U-shaped, with increased risk at both high and low sodium intake." The findings showed that increased mortality from excessive salt intake was primarily associated with individuals with hypertension. The levels of increased mortality among those with restricted salt intake appeared to be similar regardless of blood pressure. This evidence shows that while those with hypertension should primarily focus on reducing sodium to recommended levels, all groups should seek to maintain
4368-480: Is found in the Earth's crust as the mineral halite (rock salt), and a tiny amount exists as suspended sea salt particles in the atmosphere. These particles are the dominant cloud condensation nuclei far out at sea, which allow the formation of clouds in otherwise non-polluted air . Salt is currently mass-produced by evaporation of seawater or brine from brine wells and salt lakes . Mining of rock salt
4480-470: Is found in the poppy family and in the rubber trees ( Para rubber tree , members of the family Euphorbiaceae , members of the mulberry and fig family , such as the Panama rubber tree Castilla elastica ), and members of the family Asteraceae . For instance, Parthenium argentatum the guayule plant, is in the tribe Heliantheae ; other latex-bearing Asteraceae with articulated laticifers include members of
4592-455: Is functional in this defense since it limits wastage and its stickiness traps insects and their mouthparts. While there exist other explanations for the existence of latex including storage and movement of plant nutrients, waste, and maintenance of water balance that "[e]ssentially none of these functions remain credible and none have any empirical support". The latex of many species can be processed to produce many materials. Natural rubber
Sodium chloride - Misplaced Pages Continue
4704-574: Is generally safe and effective for most plants. Sodium chloride is used together with water as one of the primary solutions for intravenous therapy . Nasal spray often contains a saline solution. Sodium chloride is also available as an oral tablet, and is taken to treat low sodium levels. Sodium chloride is the principal extinguishing agent in dry-powder fire extinguishers that are used on combustible metal fires, for metals such as magnesium, zirconium, titanium, and lithium (Class D extinguishers). The salt forms an oxygen-excluding crust that smothers
4816-534: Is made up of just under 40% sodium by weight, so a 6 g serving (1 teaspoon) contains about 2,400 mg of sodium. Sodium serves a vital purpose in the human body: via its role as an electrolyte, it helps nerves and muscles to function correctly, and it is one factor involved in the osmotic regulation of water content in body organs ( fluid balance ). Most of the sodium in the Western diet comes from salt. The habitual salt intake in many Western countries
4928-583: Is mandatory in the rite of the Tridentine Mass . Salt is used in the third item (which includes an Exorcism ) of the Celtic Consecration ( cf. Gallican Rite ) that is employed in the consecration of a church, and it is permitted to be added to the water "where it is customary" in the Roman Catholic rite of Holy water. The Bible makes multiple mentions of salt , both of the mineral itself and as
5040-547: Is more common in some European countries where water fluoridation is not carried out. In France , 35% of the table salt sold contains added sodium fluoride . Unrefined sea salt contains small amounts of magnesium and calcium halides and sulfates , traces of algal products , salt-resistant bacteria and sediment particles. The calcium and magnesium salts confer a faintly bitter overtone, and they make unrefined sea salt hygroscopic (i.e., it gradually absorbs moisture from air if stored uncovered). Algal products contribute
5152-401: Is more formally called table salt . In the form of a natural crystalline mineral, salt is also known as rock salt or halite . Salt is essential for life in general (being the source of the essential dietary minerals sodium and chlorine ), and saltiness is one of the basic human tastes . Salt is one of the oldest and most ubiquitous food seasonings , and is known to uniformly improve
5264-409: Is mostly sodium chloride (NaCl). Sea salt and mined salt may contain trace elements . Mined salt is often refined. Salt crystals are translucent and cubic in shape; they normally appear white but impurities may give them a blue or purple tinge. When dissolved in water sodium chloride separates into Na and Cl ions, and the solubility is 359 grams per litre. From cold solutions, salt crystallises as
5376-432: Is not to be confused with plant sap ; it is a distinct substance, separately produced, and with different functions. The word latex is also used to refer to natural latex rubber , particularly non- vulcanized rubber. Such is the case in products like latex gloves , latex condoms , latex clothing , and balloons . Latex : Colloidal dispersion of polymer particles in a liquid. Synthetic latex : Latex obtained as
5488-428: Is prepared by roasting salt in a bamboo container plugged with mud at both ends. This product absorbs minerals from the bamboo and the mud, and has been claimed to increase the anticlastogenic and antimutagenic properties of doenjang (a fermented bean paste). Kosher or kitchen salt has a larger grain size than table salt and is used in cooking. It can be useful for brining , in bread or pretzel making, and as
5600-589: Is present in all parts of the mature plant, including roots, stems, leaves , and sometimes the fruits . It is particularly noticeable in the cortical tissues. Latex is usually exuded as a white liquid, but is some cases it can be clear, yellow or red, as in Cannabaceae . Latex is produced by 20,000 flowering plant species from over 40 families . These include both dicots and monocots . Latex has been found in 14 percent of tropical plant species, as well as six percent of temperate plant species. Several members of
5712-586: Is primarily added as a flavor enhancer and preservative . It also is used as a carrier for other ingredients, dehydrating agent, enzyme inhibitor and tenderizer. In baking, salt is added to control the rate of fermentation in bread dough. It also is used to strengthen the gluten (the elastic protein-water complex in certain doughs) and as a flavor enhancer, such as a topping on baked goods. The food-processing category also contains grain mill products. These products consist of milling flour and rice and manufacturing cereal breakfast food and blended or prepared flour. Salt
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#17328445971975824-435: Is recommended by developed countries, one review recommended that sodium intake be reduced to at least 1,200 mg (contained in 3 g of salt) per day, as a further reduction in salt intake led to a greater fall in systolic blood pressure for all age groups and ethnicities. Another review indicated that there is inconsistent/insufficient evidence to conclude that reducing sodium intake to lower than 2,300 mg per day
5936-543: Is refined by treatment with chemicals that precipitate most impurities (largely magnesium and calcium salts). Multiple stages of evaporation are then applied. Some salt is produced using the Alberger process , which involves vacuum pan evaporation combined with the seeding of the solution with cubic crystals, and produces a grainy-type flake. The Ayoreo , an indigenous group from the Paraguayan Chaco , obtain their salt from
6048-496: Is the most important product obtained from latex; more than 12,000 plant species yield latex containing rubber, though in the vast majority of those species the rubber is not suitable for commercial use. This latex is used to make many other products including mattresses , gloves , swim caps , condoms , catheters and balloons . Dried latex from the opium poppy is called opium , the source of several useful analgesic alkaloids such as codeine , thebaine , and morphine ,
6160-560: Is then reacted with sulfuric acid and a reducing agent such as methanol to manufacture chlorine dioxide , a bleaching chemical that is widely used to bleach wood pulp . In tanning and leather treatment, salt is added to animal hides to inhibit microbial activity on the underside of the hides and to attract moisture back into the hides. In rubber manufacture, salt is used to make buna , neoprene , and white rubber types. Salt brine and sulfuric acid are used to coagulate an emulsified latex made from chlorinated butadiene . Salt also
6272-409: Is used as a flux in the production of aluminium . For this purpose, a layer of melted salt floats on top of the molten metal and removes iron and other metal contaminants. It is used in the manufacture of soaps and glycerine , where it is used to saponify fats. As an emulsifier, salt is used in the manufacture of synthetic rubber , and another use is in the firing of pottery , when salt added to
6384-426: Is used as a brine rinse to separate organic contaminants, to promote "salting out" of dyestuff precipitates, and to blend with concentrated dyes to increase yield in dyebaths and make the colors look sharper. One of its main roles is to provide the positive ion charge to promote the absorption of negatively charged ions of dyes. For use in the pulp and paper industry , it is used to manufacture sodium chlorate , which
6496-456: Is used extensively in cooking as a flavouring, and in cooking techniques such as with salt crusts and brining . The main sources of salt in the Western diet, apart from direct use, are bread and cereals, meat, and dairy products. In many East Asian cultures, salt is not traditionally used as a condiment. In its place, condiments such as soy sauce , fish sauce and oyster sauce tend to have
6608-460: Is used in ceremonies like house-warmings and weddings. In Jainism , devotees lay an offering of raw rice with a pinch of salt before a deity to signify their devotion and salt is sprinkled on a person's cremated remains before the ashes are buried. Salt is believed to ward off evil spirits in Mahayana Buddhist tradition, and when returning home from a funeral , a pinch of salt is thrown over
6720-441: Is used in many cuisines, and it is often found in salt shakers on diners' eating tables for their personal use on food. Salt is also an ingredient in many manufactured foodstuffs. Table salt is a refined salt containing about 97 to 99 percent sodium chloride . Usually, anticaking agents such as sodium aluminosilicate or magnesium carbonate are added to make it free-flowing. Iodized salt , containing potassium iodide ,
6832-477: Is used in religious ceremonies and has other cultural and traditional significance. Salt is processed from salt mines , and by the evaporation of seawater ( sea salt ) and mineral-rich spring water in shallow pools. The greatest single use for salt (sodium chloride) is as a feedstock for the production of chemicals. It is used to produce caustic soda and chlorine , and in the manufacture of products such as polyvinyl chloride , plastics , and paper pulp . Of
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#17328445971976944-569: Is used in the Solvay process to produce sodium carbonate and calcium chloride . Sodium carbonate, in turn, is used to produce glass , sodium bicarbonate , and dyes , as well as a myriad of other chemicals. In the Mannheim process , sodium chloride is used for the production of sodium sulfate and hydrochloric acid . Sodium chloride is heavily used, so even relatively minor applications can consume massive quantities. In oil and gas exploration, salt
7056-617: Is used in the preparation of butter and cheese products. As a flavouring, salt enhances the taste of other foods by suppressing the bitterness of those foods making them more palatable and relatively sweeter. Before the advent of electrically powered refrigeration , salting was one of the main methods of food preservation . Thus, herring contains 67 mg sodium per 100 g, while kipper , its preserved form, contains 990 mg. Similarly, pork typically contains 63 mg while bacon contains 1,480 mg, and potatoes contain 7 mg but potato crisps 800 mg per 100 g. Salt
7168-434: Is widely available. Some people put a desiccant , such as a few grains of uncooked rice or a saltine cracker , in their salt shakers to absorb extra moisture and help break up salt clumps that may otherwise form. Some table salt sold for consumption contains additives that address a variety of health concerns, especially in the developing world. The identities and amounts of additives vary from country to country. Iodine
7280-477: The Cichorieae , a clade whose members produce latex, some of them in commercially interesting amounts. This includes Taraxacum kok-saghyz , a species cultivated for latex production. In the milkweed and spurge families, on the other hand, the laticiferous system is formed quite differently. Early in the development of the seedling, latex cells differentiate, and as the plant grows these latex cells grow into
7392-570: The Committee on Toxicity in 1988. Other anticaking agents sometimes used include tricalcium phosphate , calcium or magnesium carbonates, fatty acid salts ( acid salts ), magnesium oxide , silicon dioxide , calcium silicate , sodium aluminosilicate and calcium aluminosilicate . Both the European Union and the United States Food and Drug Administration permitted the use of aluminium in
7504-613: The German word Salz , salt. Hallstatt was the site of the world's first salt mine . The town gave its name to the Hallstatt culture that began mining for salt in the area in about 800 BC. Around 400 BC, the townsfolk, who had previously used pickaxes and shovels , began open pan salt making . During the first millennium BC, Celtic communities grew rich trading salt and salted meat to Ancient Greece and Ancient Rome in exchange for wine and other luxuries. The word salary comes from
7616-625: The Latin word for salt. The reason for this is unknown; a persistent modern claim that the Roman Legions were sometimes paid in salt is baseless. The word salad literally means "salted", and comes from the ancient Roman practice of salting leaf vegetables . Wars have been fought over salt. Venice won a war with Genoa over the product, and it played a role in the American Revolution . Cities on overland trade routes grew rich by levying duties , and towns like Liverpool flourished on
7728-413: The dihydrate NaCl·2H 2 O. Solutions of sodium chloride have very different properties from those of pure water; the freezing point is −21.12 °C (−6.02 °F) for 23.31 wt% of salt, and the boiling point of saturated salt solution is around 108.7 °C (227.7 °F). Salt is essential to the health of humans and other animals, and it is one of the five basic taste sensations . Salt
7840-797: The obsidian trade in Anatolia in the Neolithic Era . Salt was included among funeral offerings found in ancient Egyptian tombs from the third millennium BC, as were salted birds, and salt fish. From about 2800 BC, the Egyptians began exporting salt fish to the Phoenicians in return for Lebanon cedar , glass, and the dye Tyrian purple ; the Phoenicians traded Egyptian salted fish and salt from North Africa throughout their Mediterranean trade empire. Herodotus described salt trading routes across Libya back in
7952-450: The tanning of hides, the preservation of meat and fish and the canning of meat and vegetables. Food-grade salt accounts for only a small part of salt production in industrialized countries (7% in Europe), although worldwide, food uses account for 17.5% of total production. In 2018, total world production of salt was 300 million tonnes , the top six producers being China (68 million),
8064-646: The 5th century BC. In the early years of the Roman Empire, roads were built for the transportation of salt from the salt imported at Ostia to the capital. In Africa, salt was used as currency south of the Sahara, and slabs of rock salt were used as coins in Abyssinia . The Tuareg have traditionally maintained routes across the Sahara especially for the transportation of salt by Azalai (salt caravans). The caravans still cross
8176-457: The UK the recommended iodine content of iodized salt is 10–22 ppm. Sodium ferrocyanide , yellow prussiate of soda, is sometimes added to salt as an anticaking agent . Such anticaking agents have been added since at least 1911 when magnesium carbonate was first added to salt to make it flow more freely. The safety of sodium ferrocyanide as a food additive was found to be provisionally acceptable by
8288-490: The United States (42 million), India (29 million), Germany (13 million), Canada (13 million) and Australia (12 million). The manufacture of salt is one of the oldest chemical industries. A major source of salt is seawater, which has a salinity of approximately 3.5%. This means that there are about 35 g (1.2 oz) of dissolved salts , predominantly sodium ( Na ) and chloride ( Cl ) ions , per kilogram (2.2 lbs) of water. The world's oceans are
8400-429: The annual global production of around three hundred million tonnes , only a small percentage is used for human consumption. Other uses include water conditioning processes, de-icing highways, and agricultural use. Edible salt is sold in forms such as sea salt and table salt, the latter of which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency . As well as its use in cooking and at
8512-674: The ash produced by burning the timber of the Indian salt tree ( Maytenus vitis-idaea ) and other trees. The largest mine operated by underground workings in the world is the Sifto mine, located mostly 550 meters below Lake Huron, in Goderich, Ontario (Canada). About seven million tons of salt are extracted from it annually. The Khewra Salt Mine in Pakistan has nineteen storeys, eleven of which are underground, and 400 km (250 mi) of passages. The salt
8624-650: The availability of salt has been pivotal to civilization. What is now thought to have been the first city in Europe is Solnitsata , in Bulgaria , which was a salt mine, providing the area now known as the Balkans with salt since 5400 BC. Salt was the best-known food preservative, especially for meat, for many thousands of years. A very ancient salt-works operation has been discovered at the Poiana Slatinei archaeological site next to
8736-400: The coast natives lost their previous profits; as of the late 1950s, sea salt was still the currency best appreciated in the interior. Salzburg , Hallstatt , and Hallein lie within 17 km (11 mi) of each other on the river Salzach in central Austria in an area with extensive salt deposits. Salzach means "salt river" while Salzburg means "salt castle", both taking their names from
8848-444: The desert from southern Niger to Bilma , although much of the trade now takes place by truck. Each camel takes two bales of fodder and two of trade goods northwards and returns laden with salt pillars and dates. In Gabon, before the arrival of Europeans, the coast people carried on a remunerative trade with those of the interior by the medium of sea salt. This was gradually displaced by the salt that Europeans brought in sacks, so that
8960-569: The export of salt extracted from the salt mines of Cheshire . Various governments have at different times imposed salt taxes on their peoples. The voyages of Christopher Columbus are said to have been financed from salt production in southern Spain, and the oppressive salt tax in France was one of the causes of the French Revolution . After being repealed, this tax was reimposed by Napoleon when he became emperor to pay for his foreign wars , and
9072-598: The fire. Since at least medieval times, people have used salt as a cleansing agent rubbed on household surfaces. It is also used in many brands of shampoo , toothpaste, and popularly to de-ice driveways and patches of ice. Sodium chloride crystals have a transmittance of at least 90% (through 1 mm) for infrared light having wavelengths in the range 0.2– 18 μm . They were used in optical components such as windows and lenses, where few non-absorbing alternatives existed in that spectral range. While inexpensive, NaCl crystals are soft and hygroscopic – when exposed to
9184-707: The first time by Blanco et al. in 1994. In a 2024 comprehensive review by Gromek et al., the last 30 years of research on LFS were summarized, focusing on its prevalence, common cross-reactions, and clinical manifestations. The review found that the prevalence of LFS in latex-allergic patients varies widely, ranging from 4% to 88%, depending on diagnostic methods, geographical regions, and study populations. The most commonly implicated fruits in LFS include banana, avocado, kiwifruit, and papaya. Clinical manifestations are predominantly systemic, with 73% of hypersensitivity symptoms being systemic and 27% localized. Gromek et al. also highlighted
9296-478: The food ingredients. The refined salt industry cites scientific studies saying that raw sea and rock salts do not contain enough iodine salts to prevent iodine deficiency diseases . Salts have diverse mineralities depending on their source, giving each a unique flavour. Fleur de sel , a natural sea salt from the surface of evaporating brine in salt pans, has a distinctive flavour varying with its source. In traditional Korean cuisine , so-called " bamboo salt "
9408-496: The formula [Na(H 2 O) 8 ], with the Na–O distance of 250 pm . The chloride ions are also strongly solvated, each being surrounded by an average of six molecules of water. Solutions of sodium chloride have very different properties from pure water. The eutectic point is −21.12 °C (−6.02 °F) for 23.31% mass fraction of salt, and the boiling point of saturated salt solution is near 108.7 °C (227.7 °F). The pH of
9520-447: The fungal kingdom also produce latex upon injury, such as Lactarius deliciosus and other milk-caps . This suggests it is the product of convergent evolution and has been selected for on many separate occasions. Latex functions to protect the plant from herbivores. The idea was first proposed in 1887 by Joseph F. James, who noted that latex of milkweed carries with it at the same time such disagreeable properties that it becomes
9632-435: The furnace vaporises before condensing onto the surface of the ceramic material, forming a strong glaze . When drilling through loose materials such as sand or gravel, salt may be added to the drilling fluid to provide a stable "wall" to prevent the hole collapsing. There are many other processes in which salt is involved. These include its use as a mordant in textile dying, to regenerate resins in water softening, for
9744-444: The gritting vehicles despite being stockpiled prior to use. In recent years this additive has also been used in table salt. Other additives had been used in road salt to reduce the total costs. For example, in the US, a byproduct carbohydrate solution from sugar-beet processing was mixed with rock salt and adhered to road surfaces about 40% better than loose rock salt alone. Because it stayed on
9856-427: The hardness. These resins are generated and regenerated using sodium chloride. The second major application of salt is for deicing and anti-icing of roads, both in grit bins and spread by winter service vehicles . In anticipation of snowfall, roads are optimally "anti-iced" with brine (concentrated solution of salt in water), which prevents bonding between the snow-ice and the road surface. This procedure obviates
9968-673: The heavy use of salt after the snowfall. For de-icing, mixtures of brine and salt are used, sometimes with additional agents such as calcium chloride and/or magnesium chloride . The use of salt or brine becomes ineffective below −10 °C (14 °F). Salt for de-icing in the United Kingdom predominantly comes from a single mine in Winsford in Cheshire . Prior to distribution it is mixed with <100 ppm of sodium ferrocyanide as an anticaking agent , which enables rock salt to flow freely out of
10080-468: The initial stage of crystal nucleation of sodium chloride. The Thermal conductivity of sodium chloride as a function of temperature has a maximum of 2.03 W/(cm K) at 8 K (−265.15 °C; −445.27 °F) and decreases to 0.069 at 314 K (41 °C; 106 °F). It also decreases with doping . From cold (sub-freezing) solutions, salt crystallises with water of hydration as hydrohalite (the dihydrate NaCl·2 H 2 O ). In 2023, it
10192-640: The iodine. Iodine deficiency affects about two billion people around the world and is the leading preventable cause of intellectual disabilities . Iodized table salt has significantly reduced disorders of iodine deficiency in countries where it is used. The amount of iodine and the specific iodine compound added to salt varies. In the United States , the Food and Drug Administration (FDA) recommends 150 micrograms of iodine per day for both men and women. US iodized salt contains 46–77 ppm (parts per million), whereas in
10304-411: The latex of Asclepias humistrata (sandhill milkweed ) kills by trapping 30% of newly hatched monarch butterfly caterpillars. Other evidence is that latex contains 50–1000× higher concentrations of defense substances than other plant tissues. These toxins include ones that are also toxic to the plant and consist of a diverse range of chemicals that are either poisonous or " antinutritive. " Latex
10416-412: The latter two compounds. In "doubly fortified salt", both iodide and iron salts are added. The latter alleviates iron deficiency anaemia , which interferes with the mental development of an estimated 40% of infants in the developing world. A typical iron source is ferrous fumarate . Another additive, especially important for pregnant women, is folic acid (vitamin B 9 ), which gives the table salt
10528-441: The latter two of which can then further be used in the synthesis and manufacture of other (typically stronger) opioids for medicinal use, and of heroin for the illegal drug trade . The opium poppy is also the source of medically useful non-analgesic alkaloids, such as papaverine and noscapine . Latex is used in many types of clothing . Worn on the body (or applied directly by painting), it tends to be skin-tight , producing
10640-447: The left shoulder as this prevents evil spirits from entering the house. In Shinto , Shio ( 塩 , lit. "salt" ) is used for ritual purification of locations and people ( harae , specifically shubatsu ), and small piles of salt are placed in dishes by entrances to wardi off evil and to attract patrons. Latex In nature, latex is found as a milky fluid , which is present in 10% of all flowering plants (angiosperms). It
10752-418: The need for standardized diagnostic criteria and severity grading systems to improve the accuracy of LFS diagnosis and treatment. Several species of the microbe genera Actinomycetes , Streptomyces , Nocardia , Micromonospora , and Actinoplanes are capable of consuming rubber latex. However, the rate of biodegradation is slow, and the growth of bacteria utilizing rubber as a sole carbon source
10864-408: The production of many chemicals, which consume most of the world's production. It is the starting point for the chloralkali process , the industrial process to produce chlorine and sodium hydroxide , according to the chemical equation This electrolysis is conducted in either a mercury cell, a diaphragm cell, or a membrane cell. Each of those uses a different method to separate the chlorine from
10976-582: The road longer, the treatment did not have to be repeated several times, saving time and money. In the technical terms of physical chemistry, the minimum freezing point of a water-salt mixture is −21.12 °C (−6.02 °F) for 23.31 wt% of salt. Freezing near this concentration is however so slow that the eutectic point of −22.4 °C (−8.3 °F) can be reached with about 25 wt% of salt. Road salt ends up in fresh-water bodies and could harm aquatic plants and animals by disrupting their osmoregulation ability. The omnipresence of salt in coastal areas poses
11088-503: The sea, salt is extracted from the vast sedimentary deposits which have been laid down over the millennia from the evaporation of seas and lakes. These sources are either mined directly, producing rock salt, or are extracted by pumping water into the deposit. In either case, the salt may be purified by mechanical evaporation of brine. Traditionally, purification was achieved in shallow open pans that were heated to accelerate evaporation. Vacuum -based methods are also employed. The raw salt
11200-440: The sodium hydroxide. Other technologies are under development due to the high energy consumption of the electrolysis, whereby small improvements in the efficiency can have large economic paybacks. Some applications of chlorine include PVC thermoplastics production, disinfectants, and solvents. Sodium hydroxide is extensively used in many different industries enabling production of paper, soap, and aluminium etc. Sodium chloride
11312-702: The spread of civilization, salt became one of the world's main trading commodities. It was of high value to the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites and other peoples of antiquity. In the Middle East, salt was used to seal an agreement ceremonially, and the ancient Hebrews made a " covenant of salt " with God and sprinkled salt on their offerings to show their trust in him. An ancient practice in time of war
11424-506: The spring rains and thaws usually dilute the concentrations of sodium in the area where salt was applied. A 2009 study found that approximately 70% of the road salt being applied in the Minneapolis-St Paul metro area is retained in the local watershed. Some agencies are substituting beer , molasses , and beet juice instead of road salt. Airlines utilize more glycol and sugar rather than salt-based solutions for deicing . Salt
11536-487: The surface of Xiechi Lake near Yuncheng in Shanxi , China, dates back to at least 6000 BC, making it one of the oldest verifiable saltworks. There is more salt in animal tissues, such as meat, blood, and milk, than in plant tissues. Nomads who subsist on their flocks and herds do not eat salt with their food, but agriculturalists, feeding mainly on cereals and vegetable matter, need to supplement their diet with salt. With
11648-623: The table, salt is present in many processed foods. Sodium is an essential element for human health via its role as an electrolyte and osmotic solute . However, excessive salt consumption increases the risk of cardiovascular diseases such as hypertension . Such health effects of salt have long been studied. Accordingly, numerous world health associations and experts in developed countries recommend reducing consumption of popular salty foods. The World Health Organization recommends that adults consume less than 2,000 mg of sodium, equivalent to 5 grams of salt, per day. All through history,
11760-451: The taste perception of food, including otherwise unpalatable food. Salting , brining , and pickling are ancient and important methods of food preservation . Some of the earliest evidence of salt processing dates to around 6000 BC, when people living in the area of present-day Romania boiled spring water to extract salts; a salt works in China dates to approximately the same period. Salt
11872-528: The time of Brahmanic sacrifices, in Hittite rituals and during festivals held by Semites and Greeks at the time of the new moon , salt was thrown into a fire where it produced crackling noises. The ancient Egyptians, Greeks and Romans invoked their gods with offerings of salt and water and some people think this to be the origin of Holy Water in the Christian faith. In Judaism , it is recommended to have either
11984-461: The vertices of a regular octahedron . In the language of close-packing , the larger chloride ions (167 pm in size) are arranged in a cubic array whereas the smaller sodium ions (116 pm) fill all the cubic gaps (octahedral voids) between them. This same basic structure is found in many other compounds and is commonly known as the NaCl structure or rock salt crystal structure. It can be represented as
12096-487: The water in ambient air, they gradually cover with "frost". This limits application of NaCl to dry environments, vacuum-sealed areas, or short-term uses such as prototyping. Materials that are mechanically stronger and less sensitive to moisture, such as zinc selenide and chalcogenide glasses , more widely used than NaCl. In solid sodium chloride, each ion is surrounded by six ions of the opposite charge as expected on electrostatic grounds. The surrounding ions are located at
12208-544: Was salting the earth : scattering salt around in a defeated city to prevent plant growth. The Bible tells the story of King Abimelech who was ordered by God to do this at Shechem , and various texts claim that the Roman general Scipio Aemilianus Africanus ploughed over and sowed the city of Carthage with salt after it was defeated in the Third Punic War (146 BC). Salt may have been used for barter in connection with
12320-479: Was discovered that under pressure, sodium chloride can form the hydrates NaCl·8.5H 2 O and NaCl·13H 2 O. The attraction between the Na and Cl ions in the solid is so strong that only highly polar solvents like water dissolve NaCl well. When dissolved in water, the sodium chloride framework disintegrates as the Na and Cl ions become surrounded by polar water molecules. These solutions consist of metal aquo complex with
12432-456: Was not finally abolished until 1946. In 1930, Mahatma Gandhi led a crowd of 100,000 protestors on the "Dandi March" or " Salt Satyagraha ", during which they made their own salt from the sea as a demonstration of their opposition to the colonial salt tax . This act of civil disobedience inspired numerous Indians and transformed the Indian independence movement into a national struggle. Salt
12544-474: Was prized by the ancient Hebrews , Greeks , Romans , Byzantines , Hittites , Egyptians , and Indians . Salt became an important article of trade and was transported by boat across the Mediterranean Sea , along specially built salt roads , and across the Sahara on camel caravans . The scarcity and universal need for salt have led nations to go to war over it and use it to raise tax revenues. Salt
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