Misplaced Pages

#351648

73-415: Polychlorinated dibenzodioxins ( PCDDs ), or simply dioxins , are a group of long-lived polyhalogenated organic compounds that are primarily anthropogenic, and contribute toxic, persistent organic pollution in the environment. They are commonly but inaccurately referred to as dioxins for simplicity, because every PCDD molecule contains a dibenzo-1,4-dioxin skeletal structure, with 1,4-dioxin as

146-613: A $ 5 trillion global enterprise, and the EU and U.S. chemical companies are the world's largest producers. Sales of the chemical business can be divided into a few broad categories, including basic chemicals (about 35% - 37% of dollar output), life sciences (30%), specialty chemicals (20% - 25%) and consumer products (about 10%). Basic chemicals, or "commodity chemicals" are a broad chemical category including polymers, bulk petrochemicals and intermediates, other derivatives and basic industrials, inorganic chemicals , and fertilizers . Polymers are

219-439: A TEF as high as 0.1. The total dioxin toxic equivalence (TEQ) value expresses the toxicity as if the mixture were pure TCDD. The TEQ approach and current TEFs have been adopted internationally as the most appropriate way to estimate the potential health risks of mixture of dioxins. Recent data suggest that this type of simple scaling factor may not be the most appropriate treatment for complex mixtures of dioxins; both transfer from

292-576: A contaminant. Children's daily intakes during breast feeding are often many times above the intakes of adults based on body weight. This is why the WHO consultation group assessed the tolerable intake so as to prevent a woman from accumulating harmful body burdens before her first pregnancy. Breast fed children usually still have higher dioxin body burdens than non breast fed children. The WHO still recommends breast feeding for its other benefits. In many countries dioxins in breast milk have decreased by even 90% during

365-504: A large scale. John Roebuck and Samuel Garbett were the first to establish a large-scale factory in Prestonpans, Scotland , in 1749, which used leaden condensing chambers for the manufacture of sulfuric acid. In the early 18th century, cloth was bleached by treating it with stale urine or sour milk and exposing it to sunlight for long periods of time, which created a severe bottleneck in production. Sulfuric acid began to be used as

438-402: A long time. 2,3,7,8-Tetrachlorodibenzodioxin (TCDD) is considered the most toxic of the congeners (for the mechanism of action, see 2,3,7,8-Tetrachlorodibenzodioxin and Aryl hydrocarbon receptor ). Other dioxin congeners including PCDFs and PCBs with dioxin-like toxicity, are given a toxicity rating from 0 to 1, where TCDD = 1 (see Dioxins and dioxin-like compounds ). This toxicity rating

511-661: A major chemicals firm in the early 20th century in America. Polymers and plastics such as polyethylene , polypropylene , polyvinyl chloride , polyethylene terephthalate , polystyrene and polycarbonate comprise about 80% of the industry's output worldwide. Chemicals are used in many different consumer goods, and are also used in many different sectors. This includes agriculture manufacturing, construction, and service industries. Major industrial customers include rubber and plastic products, textiles , apparel, petroleum refining, pulp and paper , and primary metals. Chemicals are nearly

584-562: A more efficient agent as well as lime by the middle of the century, but it was the discovery of bleaching powder by Charles Tennant that spurred the creation of the first great chemical industrial enterprise. His powder was made by reacting chlorine with dry slaked lime and proved to be a cheap and successful product. He opened the St Rollox Chemical Works , north of Glasgow , and production went from just 52 tons in 1799 to almost 10,000 tons just five years later. Soda ash

657-630: A site separate from the production plant(s). The scale of chemical manufacturing tends to be organized from largest in volume ( petrochemicals and commodity chemicals ), to specialty chemicals , and the smallest, fine chemicals . The petrochemical and commodity chemical manufacturing units are on the whole single product continuous processing plants. Not all petrochemical or commodity chemical materials are made in one single location, but groups of related materials often are to induce industrial symbiosis as well as material, energy and utility efficiency and other economies of scale . Those chemicals made on

730-485: A variety of uses) coincided with the beginnings of the Industrial Revolution . One of the first chemicals to be produced in large amounts through industrial processes was sulfuric acid . In 1736 pharmacist Joshua Ward developed a process for its production that involved heating sulfur with saltpeter, allowing the sulfur to oxidize and combine with water. It was the first practical production of sulphuric acid on

803-626: A vast array of manufactured products, from wood treatments to cookware coatings, to non-stick, waterproof, and fire-resistant coatings, cosmetics, medicine, electronic fluids, food containers, and wrappings, in everything from furniture and furnishings, automobiles , airplanes , plastics , clothing and cloth, surgery, insulation, adhesives, paints, sealants, lubricating oils, polyurethane foams, cancer therapy, and medical imaging. They are also heavily used in pest control . PHCs include notoriously dangerous substances, including Agent Orange , DDT , and other pesticides . Many non-pesticide PHCs have

SECTION 10

#1733105635352

876-579: A wide variety of solid, liquid, and gaseous materials. Most of these products serve to manufacture other items, although a smaller number go directly to consumers. Solvents , pesticides , lye , washing soda , and portland cement provide a few examples of products used by consumers. The industry includes manufacturers of inorganic - and organic -industrial chemicals, ceramic products, petrochemicals, agrochemicals, polymers and rubber (elastomers), oleochemicals (oils, fats, and waxes), explosives, fragrances and flavors. Examples of these products are shown in

949-423: Is a list of the top 25 chemical companies by chemical sales in 2015. (Note: Chemical sales represent only a portion of total sales for some companies.) Top chemical companies by chemical sales in 2015. [REDACTED] London , United Kingdom From the perspective of chemical engineers, the chemical industry involves the use of chemical processes such as chemical reactions and refining methods to produce

1022-414: Is an issue for some in the chemical industries , historically for those making chlorophenols or chlorophenoxy acid herbicides or in the application of chemicals, notably herbicides. In many developed nations there are now emissions regulations which have dramatically decreased the emissions and thus alleviated some concerns, although the lack of continuous sampling of dioxin emissions causes concern about

1095-476: Is any compound with multiple substitutions of halogens . They are of particular interest and importance because they bioaccumulate in humans, and comprise a superset of which has many toxic and carcinogenic industrial chemicals as members. PBDEs , PCBs , dioxins (PCDDs) and PFCs are all polyhalogenated compounds. They are generally non- miscible in organic solvents or water, but miscible in some hydrocarbons from which they often derive. PHCs are used in

1168-418: Is as low as 0.5 to 2 μg/kg body weight, whereas the oral LD50 for hamsters can be as high as 1 to 5 mg/kg body weight, a difference of as much as thousandfold or more, and even among rat strains there may be thousandfold differences. Agent Orange was the code name for one of the herbicides and defoliants the U.S. military used as part of its herbicidal warfare program, Operation Ranch Hand , during

1241-581: Is called the Toxic Equivalence Factor concept, or TEF . TEFs are consensus values and, because of the strong species dependence for toxicity, are listed separately for mammals, fish, and birds. TEFs for mammalian species are generally applicable to human risk calculations. The TEFs have been developed from detailed assessment of literature data to facilitate both risk assessment and regulatory control. Many other compounds may also have dioxin-like properties, particularly non-ortho PCBs , one of which has

1314-492: Is not well controlled. Compounds involved include the wood preservative pentachlorophenol , and also herbicides such as 2,4-dichlorophenoxyacetic acid (or 2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Higher levels of chlorination require higher reaction temperatures and greater dioxin production. Dioxins may also be formed during the photochemical breakdown of the common antimicrobial compound triclosan . Tolerable daily, monthly or annual intakes have been set by

1387-407: Is now the largest source of dioxin emissions, producing about one third of the total output. In incineration, dioxins can also reform or form de novo in the atmosphere above the stack as the exhaust gases cool through a temperature window of 600 to 200 °C. The most common method of reducing the quantity of dioxins reforming or forming de novo is through rapid (30 millisecond) quenching of

1460-488: Is stabilized by the two flanking benzene rings . In PCDDs, chlorine atoms are attached to this structure at any of 8 different places on the molecule, at positions 1–4 and 6–9. There are 75 different PCDD congeners (that is, related dioxin compounds). The toxicity of PCDDs depends on the number and positions of the chlorine atoms. Congeners that have chlorine in the 2, 3, 7, and 8 positions have been found to be significantly toxic. In fact, 7 congeners have chlorine atoms in

1533-404: The Industrial Revolution matured. Originally, large quantities of alkaline waste were vented into the environment from the production of soda, provoking one of the first pieces of environmental legislation to be passed in 1863. This provided for close inspection of the factories and imposed heavy fines on those exceeding the limits on pollution. Methods were devised to make useful byproducts from

SECTION 20

#1733105635352

1606-623: The Vietnam War from 1961 to 1971. It was a mixture of 2,4,5-T and 2,4-D . The 2,4,5-T used was contaminated with 2,3,7,8-tetrachlorodibenzodioxin (TCDD), an extremely toxic dioxin compound . During the Vietnam war, between 1962 and 1971, the United States military sprayed 20,000,000 U.S. gallons (76,000,000 L) of chemical herbicides and defoliants in Vietnam, eastern Laos and parts of Cambodia, as part of Operation Ranch Hand. By 1971, 12% of

1679-601: The World Health Organization and a number of governments. Dioxins enter the general population almost exclusively from ingestion of food, specifically through the consumption of fish, meat, and dairy products since dioxins are fat-soluble and readily climb the food chain . Children are passed substantial body burdens by their mothers, and breastfeeding increases the child's body burden. Dioxin exposure can also occur from contact with Pentachlorophenol (Penta) treated lumber as Pentachlorophenol often contains dioxins as

1752-791: The $ 546 billion global specialty chemical market was 33% Paints, Coating and Surface Treatments, 27% Advanced Polymer, 14% Adhesives and Sealants, 13% additives, and 13% pigments and inks. Speciality chemicals are sold as effect or performance chemicals. Sometimes they are mixtures of formulations, unlike " fine chemicals ," which are almost always single-molecule products. Consumer products include direct product sales of chemicals such as soaps , detergents , and cosmetics . Typical growth rates are 0.8 to 1.0 times GDP. Consumers rarely come into contact with basic chemicals. Polymers and specialty chemicals are materials that they encounter everywhere daily. Examples are plastics, cleaning materials, cosmetics, paints & coatings, electronics, automobiles and

1825-745: The 1862 London International Exhibition, anticipated many of the modern aesthetic and utility uses of plastics. The industrial production of soap from vegetable oils was started by William Lever and his brother James in 1885 in Lancashire based on a modern chemical process invented by William Hough Watson that used glycerin and vegetable oils . By the 1920s, chemical firms consolidated into large conglomerates ; IG Farben in Germany, Rhône-Poulenc in France and Imperial Chemical Industries in Britain. Dupont became

1898-502: The British soda industry was able to rapidly expand. James Muspratt 's chemical works in Liverpool and Charles Tennant's complex near Glasgow became the largest chemical production centres anywhere. By the 1870s, the British soda output of 200,000 tons annually exceeded that of all other nations in the world combined. These huge factories began to produce a greater diversity of chemicals as

1971-518: The European Chemical industry saw its sales increase from 295 billion Euros to 539 billion Euros, a picture of constant growth. Despite this, the European industry's share of the world chemical market has fallen from 36% to 20%. This has resulted from the huge increase in production and sales in emerging markets like India and China. The data suggest that 95% of this impact is from China alone. In 2012

2044-784: The Food and Drug Administration. Pesticides, also called "crop protection chemicals", are about 10% of this category and include herbicides , insecticides , and fungicides . Specialty chemicals are a category of relatively high-valued, rapidly growing chemicals with diverse end product markets. Typical growth rates are one to three times GDP with prices over a dollar per pound. They are generally characterized by their innovative aspects. Products are sold for what they can do rather than for what chemicals they contain. Products include electronic chemicals, industrial gases , adhesives and sealants as well as coatings, industrial and institutional cleaning chemicals, and catalysts. In 2012, excluding fine chemicals,

2117-458: The Table below. Related industries include petroleum , glass , paint , ink , sealant , adhesive , pharmaceuticals and food processing . Chemical processes such as chemical reactions operate in chemical plants to form new substances in various types of reaction vessels. In many cases, the reactions take place in special corrosion-resistant equipment at elevated temperatures and pressures with

2190-505: The U.S. there are 170 major chemical companies. They operate internationally with more than 2,800 facilities outside the U.S. and 1,700 foreign subsidiaries or affiliates operating. The U.S. chemical output is $ 750 billion a year. The U.S. industry records large trade surpluses and employs more than a million people in the United States alone. The chemical industry is also the second largest consumer of energy in manufacturing and spends over $ 5 billion annually on pollution abatement. In Europe,

2263-537: The US EPA reported that dioxins are a probable carcinogen , but noted that non-cancer effects (reproduction and sexual development, immune system) may pose a greater threat to human health. TCDD , the most toxic of the dibenzodioxins, is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). TCDD has a half-life of approximately 8 years in humans, although at high concentrations,

Polychlorinated dibenzodioxins - Misplaced Pages Continue

2336-621: The alkali. The Solvay process was developed by the Belgian industrial chemist Ernest Solvay in 1861. In 1864, Solvay and his brother Alfred constructed a plant in Charleroi Belgium. In 1874, they expanded into a larger plant in Nancy , France. The new process proved more economical and less polluting than the Leblanc method, and its use spread. In the same year, Ludwig Mond visited Solvay to acquire

2409-490: The beginning of the 20th century, including organochloride -related manufacturing, incineration of chlorine-containing substances such as polyvinyl chloride (PVC), and chlorine bleaching of paper. Forest fires and volcanic eruptions have also been cited as an airborne source, although their contribution to the current levels of PCDD accumulation are minor in comparison. Incidents of dioxin poisoning resulting from industrial emissions and accidents were first recorded as early as

2482-447: The central ring . Members of the PCDD family bioaccumulate in humans and wildlife because of their lipophilic properties, and may cause developmental disturbances and cancer . Because dioxins can persist in the environment for more than 100 years, the majority of PCDD pollution today is not the result of recent emissions, but the cumulative result of synthetic processes undertaken since

2555-440: The chemical, plastics, and rubber sectors are among the largest industrial sectors. Together they generate about 3.2 million jobs in more than 60,000 companies. Since 2000 the chemical sector alone has represented 2/3 of the entire manufacturing trade surplus of the EU. In 2012, the chemical sector accounted for 12% of the EU manufacturing industry's added value. Europe remains the world's biggest chemical trading region with 43% of

2628-541: The clustering and integration mentioned above, some 50% of the United Kingdom's petrochemical and commodity chemicals are produced by the Northeast of England Process Industry Cluster on Teesside . Specialty chemical and fine chemical manufacturing are mostly made in discrete batch processes. These manufacturers are often found in similar locations but in many cases, they are to be found in multi-sector business parks. In

2701-870: The consumer. Annually the American Chemistry Council tabulates the US production volume of the top 100 chemicals. In 2000, the aggregate production volume of the top 100 chemicals totaled 502 million tons, up from 397 million tons in 1990. Inorganic chemicals tend to be the largest volume but much smaller in dollar revenue due to their low prices. The top 11 of the 100 chemicals in 2000 were sulfuric acid (44 million tons), nitrogen (34), ethylene (28), oxygen (27), lime (22), ammonia (17), propylene (16), polyethylene (15), chlorine (13), phosphoric acid (13) and diammonium phosphates (12). The largest chemical producers today are global companies with international operations and plants in numerous countries. Below

2774-749: The data from the European Chemical Industry Council shows that five European countries account for 71% of the EU's chemicals sales. These are Germany, France, the United Kingdom, Italy and the Netherlands. The chemical industry has seen growth in China, India, Korea, the Middle East, South East Asia, Nigeria and Brazil. The growth is driven by changes in feedstock availability and price, labor and energy costs, differential rates of economic growth and environmental pressures. Just as companies emerge as

2847-469: The developing immune , nervous , and reproductive systems . The most sensitive effects are caused at body burdens relatively close to those reported in humans. Among the animals for which TCDD toxicity has been studied, there is strong evidence for the following effects: The LD50 of dioxin also varies wildly between species with the most notable disparity being between the ostensibly similar species of hamster and guinea pig. The oral LD50 for guinea pigs

2920-546: The dollar output of the chemistry business) include differentiated chemical and biological substances, pharmaceuticals , diagnostics, animal health products , vitamins , and pesticides . While much smaller in volume than other chemical sectors, their products tend to have high prices - over ten dollars per pound - growth rates of 1.5 to 6 times GDP , and research and development spending at 15 to 25% of sales. Life science products are usually produced with high specifications and are closely scrutinized by government agencies such as

2993-547: The early 19th century. The coal tar and ammoniacal liquor residues of coal gas manufacture for gas lighting began to be processed in 1822 at the Bonnington Chemical Works in Edinburgh to make naphtha , pitch oil (later called creosote ), pitch , lampblack ( carbon black ) and sal ammoniac ( ammonium chloride ). Ammonium sulphate fertiliser, asphalt road surfacing , coke oil and coke were later added to

Polychlorinated dibenzodioxins - Misplaced Pages Continue

3066-565: The elimination rate is enhanced by metabolism. The health effects of dioxins are mediated by their action on a cellular receptor, the aryl hydrocarbon receptor (AhR). Exposure to high levels of dioxins in humans causes a severe form of persistent acne , known as chloracne . High occupational or accidental levels of exposures to dioxins have been shown by epidemiological studies to lead to an increased risk of tumors at all sites. Other effects in humans (at high dose levels) may include: Recent studies have shown that high exposure to dioxins changes

3139-477: The exhaust gases through that 400 °C window. Incinerator emissions of dioxins have been reduced by over 90% as a result of new emissions control requirements. Incineration in developed countries is now a very minor contributor to dioxin emissions. Dioxins are also generated in reactions that do not involve burning — such as chlorine bleaching fibers for paper or textiles, and in the manufacture of chlorinated phenols, particularly when reaction temperature

3212-433: The first synthetic perfumes. German industry quickly began to dominate the field of synthetic dyes. The three major firms BASF , Bayer , and Hoechst produced several hundred different dyes. By 1913, German industries produced almost 90% of the world's supply of dyestuffs and sold approximately 80% of their production abroad. In the United States, Herbert Henry Dow's use of electrochemistry to produce chemicals from brine

3285-599: The highly chlorinated dioxins are stored in fatty tissues and are neither readily metabolized nor excreted. The estimated elimination half-life for highly chlorinated dioxins (4–8 chlorine atoms) in humans ranges from 4.9 to 13.1 years. The persistence of a particular dioxin congener in an animal is thought to be a consequence of its structure. Dioxins with no lateral (2, 3, 7, and 8) chlorines, which thus contain hydrogen atoms on adjacent pairs of carbons, can more readily be oxidized by cytochromes P450 . The oxidized dioxins can then be more readily excreted rather than stored for

3358-447: The lack of controlled dose experiments, studies in animals have shown that dioxin causes a wide variety of toxic effects. In particular, TCDD has been shown to be teratogenic , mutagenic , carcinogenic , immunotoxic , and hepatotoxic . Furthermore, alterations in multiple endocrine and growth factor systems have been reported. The most sensitive effects, observed in multiple species, appear to be developmental, including effects on

3431-667: The largest of scales are made in a few manufacturing locations around the world, for example in Texas and Louisiana along the Gulf Coast of the United States , on Teesside ( United Kingdom ), and in Rotterdam in the Netherlands . The large-scale manufacturing locations often have clusters of manufacturing units that share utilities and large-scale infrastructure such as power stations , port facilities , and road and rail terminals. To demonstrate

3504-697: The largest revenue segment and includes all categories of plastics and human-made fibers. The major markets for plastics are packaging , followed by home construction, containers, appliances, pipe, transportation, toys, and games. Principal raw materials for polymers are bulk petrochemicals like ethylene, propylene and benzene. Petrochemicals and intermediate chemicals are primarily made from liquefied petroleum gas (LPG), natural gas and crude oil fractions. Large volume products include ethylene , propylene , benzene , toluene , xylenes , methanol , vinyl chloride monomer (VCM), styrene , butadiene , and ethylene oxide . These basic or commodity chemicals are

3577-450: The main producers of the chemical industry, we can also look on a more global scale at how industrialized countries rank, with regard to the billions of dollars worth of production a country or region could export. Though the business of chemistry is worldwide in scope, the bulk of the world's $ 3.7 trillion chemical output is accounted for by only a handful of industrialized nations. The United States alone produced $ 689 billion, 18.6 percent of

3650-526: The manufacture of superphosphate of lime . Processes for the vulcanization of rubber were patented by Charles Goodyear in the United States and Thomas Hancock in England in the 1840s. The first synthetic dye was discovered by William Henry Perkin in London . He partly transformed aniline into a crude mixture which, when extracted with alcohol, produced a substance with an intense purple colour. He also developed

3723-606: The materials used in home construction. These specialty products are marketed by chemical companies to the downstream manufacturing industries as pesticides , specialty polymers , electronic chemicals, surfactants , construction chemicals, Industrial Cleaners, flavours and fragrances , specialty coatings, printing inks, water-soluble polymers, food additives , paper chemicals , oil field chemicals, plastic adhesives, adhesives and sealants , cosmetic chemicals , water management chemicals , catalysts , and textile chemicals. Chemical companies rarely supply these products directly to

SECTION 50

#1733105635352

3796-406: The mid 19th century during the Industrial Revolution . The word "dioxins" may also refer to other similarly acting chlorinated compounds (see Dioxins and dioxin-like compounds ). The structure of dibenzo-1,4-dioxin consists of two benzene rings joined by two oxygen bridges. This makes the compound an aromatic di ether . The name dioxin formally refers to the central dioxygenated ring, which

3869-633: The most recent US EPA data, the major sources of dioxins are broadly in the following types: When first carried out in 1987, the original US EPA inventory of dioxin sources revealed that incineration represented more than 80% of known dioxin sources. As a result, US EPA implemented new emissions requirements. These regulations succeeded in reducing dioxin stack emissions from incinerators. Incineration of municipal solid waste , medical waste , sewage sludge , and hazardous waste together now produce less than 3% of all dioxin emissions. Since 1987, however, backyard barrel burning has showed almost no decrease, and

3942-562: The news with the poisoning of President Viktor Yushchenko of Ukraine in 2004, the Naples Mozzarella Crisis, the 2008 Irish pork crisis , and the German feed incident of 2010. The United States Environmental Protection Agency inventory of sources of dioxin-like compounds is possibly the most comprehensive review of the sources and releases of dioxins, but other countries now have substantial research as well. Occupational exposure

4015-437: The product line. The late 19th century saw an explosion in both the quantity of production and the variety of chemicals that were manufactured. Large chemical industries arose in Germany and later in the United States. Production of artificial manufactured fertilizer for agriculture was pioneered by Sir John Lawes at his purpose-built Rothamsted Research facility. In the 1840s he established large works near London for

4088-578: The product will meet required specifications . More organizations within the industry are implementing chemical compliance software to maintain quality products and manufacturing standards. The products are packaged and delivered by many methods, including pipelines, tank-cars, and tank-trucks (for both solids and liquids), cylinders, drums, bottles, and boxes. Chemical companies often have a research-and-development laboratory for developing and testing products and processes. These facilities may include pilot plants and such research facilities may be located at

4161-488: The ratio of male to female births among a population such that more females are born than males. Dioxins accumulate in food chains in a fashion similar to other chlorinated compounds ( bioaccumulation ). This means that even small concentrations in contaminated water can be concentrated up a food chain to dangerous levels because of the long biological half life and low water solubility of dioxins. While it has been difficult to establish specific health effects in humans due to

4234-541: The ratio of the analyte to the appropriate isotopically labeled internal standard. Also novel bio-assays like DR CALUX are nowadays used in identification of dioxins and dioxin-like compounds. The advantage in respect to HRGC/HRMS is that it is able to scan many samples at lower costs. Also it is able to detect all compounds that interact with the Ah-receptor which is responsible for carcinogenic effects. Polyhalogenated compound A polyhalogenated compound ( PHC )

4307-521: The relevant positions which were considered toxic by the World Health Organization toxic equivalent (WHO-TEQ) scheme. Low concentrations of dioxins existed in nature prior to industrialization as a result of natural combustion and geological processes. Dioxins were first unintentionally produced as by-products from 1848 onwards as Leblanc process plants started operating in Germany. The first intentional synthesis of chlorinated dibenzodioxin

4380-400: The revenue output) make up the oldest of the chemical categories. Products include salt , chlorine , caustic soda , soda ash , acids (such as nitric acid , phosphoric acid , and sulfuric acid ), titanium dioxide , and hydrogen peroxide . Fertilizers are the smallest category (about 6 percent) and include phosphates , ammonia , and potash chemicals. Life sciences (about 30% of

4453-484: The rights to use his process, and he and John Brunner formed Brunner, Mond & Co. , and built a Solvay plant at Winnington , England. Mond was instrumental in making the Solvay process a commercial success. He made several refinements between 1873 and 1880 that removed byproducts that could inhibit the production of sodium carbonate in the process. The manufacture of chemical products from fossil fuels began at scale in

SECTION 60

#1733105635352

4526-472: The same safety issues as pesticides. Despite bioaccumulating in humans, it has been claimed that a method during manufacture using anaerobic bacteria may be efficacious Chemical industry Various professionals are involved in the chemical industry including chemical engineers, chemists and lab technicians. Although chemicals were made and used throughout history, the birth of the heavy chemical industry (production of chemicals in large quantities for

4599-638: The source and absorption and elimination vary among different congeners, and the TEF value is not able to accurately reflect this. Dioxins and other persistent organic pollutants (POPs) are subject to the Stockholm Convention . The treaty obliges signatories to take measures to eliminate where possible, and minimize where not possible to eliminate, all sources of dioxin. Dioxins build up primarily in fatty tissues over time ( bioaccumulation ), so even small exposures may eventually reach dangerous levels. In 1994,

4672-475: The starting materials used to manufacture many polymers and other more complex organic chemicals particularly those that are made for use in the specialty chemicals category. Other derivatives and basic industrials include synthetic rubber , surfactants , dyes and pigments , turpentine , resins , carbon black , explosives , and rubber products and contribute about 20 percent of the basic chemicals' external sales. Inorganic chemicals (about 12% of

4745-1224: The total area of South Vietnam had been sprayed with defoliating chemicals, which were often applied at rates that were 13 times as high as the legal USDA limit. In South Vietnam alone, an estimated 10 million hectares of agricultural land were ultimately destroyed. In some areas, TCDD concentrations in soil and water were hundreds of times greater than the levels considered safe by the U.S. Environmental Protection Agency . According to Vietnamese Ministry of Foreign Affairs, 4.8 million Vietnamese people were exposed to Agent Orange, resulting in 400,000 people being killed or maimed, and 500,000 children born with birth defects . The Red Cross of Vietnam estimates that up to 1 million people are disabled or have health problems due to Agent Orange contamination. The United States government has challenged these figures as being unreliable and unrealistically high. The analyses used to determine these compounds' relative toxicity share common elements that differ from methods used for more traditional analytical determinations. The preferred methods for dioxins and related analyses use high resolution gas chromatography/mass spectrometry (HRGC/HRMS). Concentrations are determined by measuring

4818-430: The two last decades. Dioxins are present in cigarette smoke . Dioxin in cigarette smoke was noted as "understudied" by the US EPA in its "Re-Evaluating Dioxin" (1995). In that same document, the US EPA acknowledged that dioxin in cigarettes is "anthropogenic" (man-made, "not likely in nature"). Dioxins are absorbed primarily through dietary intake of fat, as this is where they accumulate in animals and humans. In humans,

4891-502: The understatement of emissions. In Belgium , through the introduction of a process called AMESA , continuous sampling showed that periodic sampling understated emissions by a factor of 30 to 50 times. Few facilities have continuous sampling. Dioxins are produced in small concentrations when organic material is burned in the presence of chlorine , whether the chlorine is present as chloride ions or as organochlorine compounds , so they are widely produced in many contexts. According to

4964-458: The use of catalysts . The products of these reactions are separated using a variety of techniques including distillation especially fractional distillation , precipitation , crystallization , adsorption , filtration , sublimation , and drying . The processes and products or products are usually tested during and after manufacture by dedicated instruments and on-site quality control laboratories to ensure safe operation and to assure that

5037-430: The world's exports and 37% of the world's imports, although the latest data shows that Asia is catching up with 34% of the exports and 37% of imports. Even so, Europe still has a trading surplus with all regions of the world except Japan and China where in 2011 there was a chemical trade balance. Europe's trade surplus with the rest of the world today amounts to 41.7 billion Euros. Over the 20 years between 1991 and 2011,

5110-440: Was a commercial success that helped to promote the country's chemical industry. The petrochemical industry can be traced back to the oil works of Scottish chemist James Young , and Canadian Abraham Pineo Gesner . The first plastic was invented by Alexander Parkes , an English metallurgist . In 1856, he patented Parkesine , a celluloid based on nitrocellulose treated with a variety of solvents. This material, exhibited at

5183-598: Was in 1872. Today, concentrations of dioxins are found in all humans, with higher levels commonly found in persons living in more industrialized countries. The most toxic dioxin, 2,3,7,8-tetrachlorodibenzodioxin (TCDD), became well known as a contaminant of Agent Orange , a herbicide used in the Malayan Emergency and the Vietnam War . Later, dioxins were found in Times Beach , Missouri and Love Canal , New York and Seveso , Italy . More recently, dioxins have been in

5256-606: Was patented in 1791 by Nicolas Leblanc who then built a Leblanc plant at Saint-Denis . He was denied his prize money because of the French Revolution . In Britain, the Leblanc process became popular. William Losh built the first soda works in Britain at the Losh, Wilson and Bell works on the River Tyne in 1816, but it remained on a small scale due to large tariffs on salt production until 1824. When these tariffs were repealed,

5329-528: Was used since ancient times in the production of glass , textile , soap , and paper , and the source of the potash had traditionally been wood ashes in Western Europe . By the 18th century, this source was becoming uneconomical due to deforestation, and the French Academy of Sciences offered a prize of 2400 livres for a method to produce alkali from sea salt ( sodium chloride ). The Leblanc process

#351648