99-419: (Redirected from Heavy Oil ) Heavy oil may refer to: Coal tar creosote , a wood preservative and waterproofing agent Diesel fuel Fuel oil that contains residual oil left over from petroleum distillation Heavy crude oil , viscous crude oil Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
198-636: A sedative and anaesthetic . It was used to treat ulcers, and as a way to sterilize the tooth and deaden the pain in case of a tooth-ache. Creosote was suggested as a treatment for tuberculosis by Reichenbach as early as 1833. Following Reichenbach, it was argued for by John Elliotson and Sir John Rose Cormack . Elliotson, inspired by the use of creosote to arrest vomiting during an outbreak of cholera , suggested its use for tuberculosis through inhalation. He also suggested it for epilepsy, neuralgia, diabetes, and chronic glanders . The idea of using it for tuberculosis failed to be accepted. Use for this purpose
297-435: A biochemical target, compounds described in patents or literature, or biocontrol organisms. Compounds that are active in the screening process, known as hits or leads, cannot be used as pesticides, except for biocontrol organisms and some potent natural products. These lead compounds need to be optimised by a series of cycles of synthesis and testing of analogs. For approval by regulatory authorities for use as pesticides,
396-421: A characteristic of ortho-oxy derivatives of benzene. It dissolves in sulfuric acid to a red liquid, which slowly changes to purple-violet. Shaken with hydrochloric acid in the absence of air, it becomes red, the color changing in the presence of air to dark brown or black. In preparation of food by smoking , guaiacol contributes mainly to the smoky taste , while the dimethyl ether of pyrogallol , syringol ,
495-462: A conclusion that it more resembled chlorinated quinones and must have been a different, entirely unrelated substance. Independently, there were investigations into the chemical nature of creosote. A study by F.K. Völkel revealed that the smell of purified creosote resembled that of guaiacol , and later studies by Heinrich Hlasiwetz identified a substance common to guaiacum and creosote that he called creosol, and he determined that creosote contained
594-590: A full creosote solution, was suggested by Hermann Sahli in 1887. He argued it had the active chemical of creosote and had the advantage of being of definite composition and having a less unpleasant taste and odor. A number of solutions of both creosote and guaiacol appeared on the market, such as phosphotal and guaicophosphal , phosphites of creosote and guaiacol; eosot and geosot , valerinates of creosote and guaicol; phosot and taphosot , phosphate and tannophospate of creosote; and creosotal and tanosal , tannates of creosote. Creosote and eucalyptus oil were also
693-889: A high-boiling petroleum oil meeting the AWPA Standard P4. The information that follows describing the other various types of creosote materials and its uses should be considered as primarily being of only historical value. This history is important, because it traces the origin of these different materials used during the 19th and early 20th centuries. Furthermore, it must be considered that these other types of creosotes – lignite-tar, wood-tar, water-gas-tar, etc. – are not currently being manufactured and have either been replaced with more-economical materials, or replaced by products that are more efficacious or safer. For some part of their history, coal-tar creosote and wood-tar creosote were thought to have been equivalent substances—albeit of distinct origins—accounting for their common name;
792-418: A medical ointment. [REDACTED] Because wood-tar creosote is used for its guaiacol and creosol content, it is generally derived from beechwood rather than other woods, since it distills with a higher proportion of those chemicals to other phenolics. The creosote can be obtained by distilling the wood tar and treating the fraction heavier than water with a sodium hydroxide solution. The alkaline solution
891-501: A mixture of creosol and guaiacol. Later investigations by Gorup-Besanez, A.E. Hoffmann , and Siegfried Marasse showed that wood-tar creosote also contained phenols, giving it a feature in common with coal-tar creosote. Historically, coal-tar creosote has been distinguished from what was thought of as creosote proper—the original substance of Reichenbach's discovery—and it has been referred to specifically as "creosote oil". But, because creosote from coal-tar and wood-tar are obtained from
990-538: A pesticide is a chemical or biological agent (such as a virus , bacterium , or fungus ) that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens , weeds, molluscs , birds , mammals , fish , nematodes (roundworms), and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors . Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species. The word pesticide derives from
1089-401: A pesticide was first seen in the 1920s with inorganic pesticides, and later it was found that development of resistance is to be expected, and measures to delay it are important. Integrated pest management (IPM) was introduced in the 1950s. By careful analysis and spraying only when an economical or biological threshold of crop damage is reached, pesticide application is reduced. This became in
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#17327903850821188-506: A poem where he praised its virtues. Pyroligneous acid was also used at the time in a medicinal water called Aqua Binelli (Binelli's water), a compound which its inventor, the Italian Fedele Binelli, claimed to have hemostatic properties in his research published in 1797. These claims have since been disproven. Given this history, and the antiseptic properties known to creosote, it became popular among physicians in
1287-650: A preservative for wood; coal-tar creosote was also formerly used as an escharotic , to burn malignant skin tissue, and in dentistry, to prevent necrosis , before its carcinogenic properties became known. The wood-tar variety has been used for meat preservation, ship treatment, and such medical purposes as an anaesthetic , antiseptic , astringent , expectorant , and laxative , though these have mostly been replaced by modern formulations. Varieties of creosote have also been made from both oil shale and petroleum , and are known as oil-tar creosote when derived from oil tar, and as water-gas-tar creosote when derived from
1386-732: A pressure process under the supervision of a licensed applicator certified by the State Departments of Agriculture. No brush-on, spray, or non-pressure uses of creosote are allowed, as specified by the EPA-approved label for the use of creosote. The use of creosote according to the AWPA Standards does not allow for mixing with other types of "creosote type" materials—such as lignite-tar creosote, oil-tar creosote, peat-tar creosote, water-gas-tar creosote, or wood-tar creosote. The AWPA Standard P3 does however, allow blending of
1485-479: A remedy used together, administered through a vaporizor and inhaler. Since then, more effective and safer treatments for tuberculosis have been developed. In the 1940s, Canadian-based Eldon Boyd experimented with guaiacol and a recent synthetic modification—glycerol guaiacolate ( guaifenesin )—on animals. His data showed that both drugs were effective in increasing secretions into the airways in laboratory animals, when high-enough doses were given. Wood-tar creosote
1584-940: A sewage farm. This later led to widespread use of creosote as a cattle wash and sheep dip . External parasites would be killed in a creosote diluted dip, and drenching tubes would be used to administer doses to the animals' stomachs to kill internal parasites. Creosoted wood blocks were a common road-paving material in the late 19th and early 20th centuries, but ultimately fell out of favor because they did not generally hold up well enough over time. Pesticide Pesticides are substances that are used to control pests . They include herbicides , insecticides , nematicides , fungicides , and many others (see table). The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. Most pesticides are used as plant protection products (also known as crop protection products), which in general protect plants from weeds , fungi, or insects . In general,
1683-413: A similar process and have some common uses, they have also been placed in the same class of substances, with the terms "creosote" or "creosote oil" referring to either product. Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is non-buoyant in water, with a specific gravity of 1.037 to 1.087, retains fluidity at
1782-431: A smoky flavor. This led him to reason that creosote was the antiseptic component contained in smoke, and he further argued that the creosote he had found in wood tar was also in coal tar, as well as amber tar and animal tar, in the same abundance as in wood tar. Soon afterward, in 1834, Friedrich Ferdinand Runge discovered carbolic acid ( phenol ) in coal-tar, and Auguste Laurent obtained it from "phenylhydrate", which
1881-476: A very low temperature, and boils at 205-225 °C. In its purest form, it is transparent. Dissolution in water requires up to 200 times the amount of water as the base creosote. This creosote is a combination of natural phenols : primarily guaiacol and creosol (4-methylguaiacol), which typically constitutes 50% of the oil; second in prevalence are cresol and xylenol ; the rest being a combination of monophenols and polyphenols . The simple phenols are not
1980-421: Is 70–75 °C and burning point is 90–100 °C, and when burned it releases a greenish smoke. The smell largely depends on the naphtha content in the creosote. If there is a high amount, it will have a naphtha-like smell, otherwise it will smell more of tar. In the process of coal-tar distillation, the distillate is collected into four fractions; the "light oil", which remains lighter than water,
2079-462: Is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood, or fossil fuel. They are typically used as preservatives or antiseptics . Some creosote types were used historically as a treatment for components of seagoing and outdoor wood structures to prevent rot (e.g., bridgework and railroad ties , see image). Samples may be found commonly inside chimney flues , where
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#17327903850822178-455: Is becoming widespread and has been used with success in countries such as Indonesia , China , Bangladesh , the U.S., Australia , and Mexico . IPM attempts to recognize the more widespread impacts of an action on an ecosystem , so that natural balances are not upset. Each use of a pesticide carries some associated risk. Proper pesticide use decreases these associated risks to a level deemed acceptable by pesticide regulatory agencies such as
2277-584: Is greenish-brown liquid, with different degrees of darkness, viscosity, and fluorescence depending on how it is made. When freshly made, the creosote is a yellow oil with a greenish cast and highly fluorescent, and the fluorescence is increased by exposure to air and light. After settling, the oil is dark green by reflected light and dark red by transmitted light. To the naked eye, it generally appears brown. The creosote (often called "creosote oil") consists almost wholly of aromatic hydrocarbons , with some amount of bases and acids and other neutral oils. The flash point
2376-456: Is similarly challenging, yet well documented in developing countries. Because of critical development periods of the fetus and newborn children, these non-working populations are more vulnerable to the effects of pesticides, and may be at increased risk of developing neurocognitive effects and impaired development. While measuring biomarkers or markers of biological effects may provide more accurate estimates of exposure, collecting these data in
2475-474: Is substantial evidence of associations between organophosphate insecticide exposures and neurobehavioral alterations. Limited evidence also exists for other negative outcomes from pesticide exposure including neurological, birth defects , and fetal death . The American Academy of Pediatrics recommends limiting exposure of children to pesticides and using safer alternatives: Pesticides are also found in majority of U.S. households with 88 million out of
2574-413: Is the main chemical responsible for the smoky aroma . Soon after it was discovered and recognized as the principle of meat smoking, wood-tar creosote became used as a replacement for the process. Several methods were used to apply the creosote. One was to dip the meat in pyroligneous acid or a water of diluted creosote, as Reichenbach did, or brush it over with them, and within one hour the meat would have
2673-423: Is then separated from the insoluble oily layer, boiled in contact with air to reduce impurities, and decomposed by diluted sulfuric acid. This produces a crude creosote, which is purified by re-solution in alkali, re-precipitation with acid, then redistilled with the fraction passing over between 200° and 225° constituting the purified creosote. When ferric chloride is added to a dilute solution, it will turn green:
2772-504: Is to find new compounds or agents with improved properties such as a new mode of action or lower application rate. Another aim is to replace older pesticides which have been banned for reasons of toxicity or environmental harm or have become less effective due to development of resistance . The process starts with testing (screening) against target organisms such as insects , fungi or plants . Inputs are typically random compounds, natural products , compounds designed to disrupt
2871-406: Is to some extent used for wood preservation , but it is generally mixed with coal-tar creosote, since the former is not as effective. Commercially available preparations of " liquid smoke ", marketed to add a smoked flavour to meat and aid as a preservative, consist primarily of creosote and other constituents of smoke. Creosote is the ingredient that gives liquid smoke its function; guaicol lends to
2970-483: Is widespread in Latin America , as around US$ 3 billion are spent each year in the region. Records indicate an increase in the frequency of pesticide poisonings over the past two decades. The most common incidents of pesticide poisoning is thought to result from exposure to organophosphate and carbamate insecticides. At-home pesticide use, use of unregulated products, and the role of undocumented workers within
3069-598: The UN Environment Programme estimate that 3 million agricultural workers in the developing world experience severe poisoning from pesticides each year, resulting in 18,000 deaths. According to one study, as many as 25 million workers in developing countries may suffer mild pesticide poisoning yearly. Other occupational exposures besides agricultural workers, including pet groomers, groundskeepers , and fumigators , may also put individuals at risk of health effects from pesticides. Pesticide use
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3168-624: The United States Environmental Protection Agency (EPA) and the Pest Management Regulatory Agency (PMRA) of Canada. DDT , sprayed on the walls of houses, is an organochlorine that has been used to fight malaria vectors (mosquitos) since the 1940s. The World Health Organization recommend this approach. It and other organochlorine pesticides have been banned in most countries worldwide because of their persistence in
3267-434: The environment or the food chain in order to be approved by the authorities. Persistent pesticides, including DDT , were banned many years ago , an exception being spraying in houses to combat malaria vectors . From biblical times until the 1950s the pesticides used were inorganic compounds and plant extracts . The inorganic compounds were derivatives of copper , arsenic , mercury, sulfur , among others, and
3366-499: The phloem or both. Non-systemic pesticides (contact pesticides) remain on the surface and act through direct contact with the target organism. Pesticides are more effective if they are systemic. Systemicity is a prerequisite for the pesticide to be used as a seed-treatment. Pesticides can be classified as persistent (non-biodegradable) or non-persistent ( biodegradable ). A pesticide must be persistent enough to kill or control its target but must degrade fast enough not to accumulate in
3465-429: The " tar bases " and generally make up about 3% of the creosote—sulfur-containing heterocycles, generally benzothiophenes —and oxygen-containing heterocycles, dibenzofurans. Lastly, creosote contains a small number of aromatic amines produced by the other substances during the distillation process and likely resulting from a combination of thermolysis and hydrogenation . The tar bases are often extracted by washing
3564-407: The "middle oil" which passes over when the light oil is removed; the "heavy oil", which sinks; and the " anthracene oil ", which when cold is mostly solid and greasy, of a buttery consistence. Creosote refers to the portion of coal tar which distills as "heavy oil", typically between 230 and 270 °C, also called "dead oil"; it sinks into water but still is fairly liquid. Carbolic acid is produced in
3663-533: The 121.1 million households indicating that they use some form of pesticide in 2012. As of 2007, there were more than 1,055 active ingredients registered as pesticides, which yield over 20,000 pesticide products that are marketed in the United States. Owing to inadequate regulation and safety precautions, 99% of pesticide-related deaths occur in developing countries that account for only 25% of pesticide usage. One study found pesticide self-poisoning
3762-487: The 19th century. A dilution of creosote in water was sold in pharmacies as Aqua creosoti , as suggested by the previous use of pyroligneous acid. It was prescribed to quell the irritability of the stomach and bowels and detoxify, treat ulcers and abscesses, neutralize bad odors, and stimulate the mucous tissues of the mouth and throat. Creosote in general was listed as an irritant , styptic , antiseptic , narcotic , and diuretic , and in small doses when taken internally as
3861-538: The 2000s and less than 40 in the 2010s. Biopesticides are cheaper to develop, since the authorities require less toxicological and environmental study. Since 2000 the rate of new biological product introduction has frequently exceeded that of conventional products. More than 25% of existing chemical pesticides contain one or more chiral centres (stereogenic centres). Newer pesticides with lower application rates tend to have more complex structures, and thus more often contain chiral centres. In cases when most or all of
3960-456: The 2020s the official policy of international organisations, industry, and many governments. With the introduction of high yielding varieties in the 1960s in the green revolution , more pesticides were used. Since the 1980s genetically modified crops were introduced, which resulted in lower amounts of insecticides used on them. Organic agriculture, which uses only non-synthetic pesticides, has grown and in 2020 represents about 1.5 per cent of
4059-619: The Latin pestis (plague) and caedere (kill). The Food and Agriculture Organization (FAO) has defined pesticide as: Pesticides can be classified by target organism (e.g., herbicides , insecticides , fungicides , rodenticides , and pediculicides – see table), Biopesticides according to the EPA include microbial pesticides, biochemical pesticides, and plant-incorporated protectants. Pesticides can be classified into structural classes, with many structural classes developed for each of
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4158-703: The USA (457 kt) was the second-largest user. Applications per cropland area in 2021 varied widely, from 10.9 kg/ hectare in Brazil to 0.8 kg/ha in the Russian Federation. The level in Brazil was about twice as high as in Argentina (5.6 kg/ha) and Indonesia (5.3 kg/ha). Insecticide use in the US has declined by more than half since 1980 (0.6%/yr), mostly due to the near phase-out of organophosphates . In corn fields,
4257-595: The Workplace". Better understanding of how pesticides elicit their toxic effects is needed before this method of exposure assessment can be applied to occupational exposure of agricultural workers. Alternative methods to assess exposure include questionnaires to discern from participants whether they are experiencing symptoms associated with pesticide poisoning. Self-reported symptoms may include headaches, dizziness, nausea, joint pain, or respiratory symptoms. Multiple challenges exist in assessing exposure to pesticides in
4356-572: The agricultural industry makes characterizing true pesticide exposure a challenge. It is estimated that 50–80% of pesticide poisoning cases are unreported. Underreporting of pesticide poisoning is especially common in areas where agricultural workers are less likely to seek care from a healthcare facility that may be monitoring or tracking the incidence of acute poisoning. The extent of unintentional pesticide poisoning may be much greater than available data suggest, particularly among developing countries. Globally, agriculture and food production remain one of
4455-632: The breakdown of acetylcholine at the neural synapse . Excess acetylcholine can lead to symptoms like muscle cramps or tremors, confusion, dizziness and nausea. Studies show that farm workers in Ethiopia, Kenya, and Zimbabwe have decreased concentrations of plasma acetylcholinesterase, the enzyme responsible for breaking down acetylcholine acting on synapses throughout the nervous system . Other studies in Ethiopia have observed reduced respiratory function among farm workers who spray crops with pesticides. Numerous exposure pathways for farm workers increase
4554-508: The coal or wood burns under variable conditions, producing soot and tarry smoke. Creosotes are the principal chemicals responsible for the stability, scent, and flavor characteristic of smoked meat; the name is derived from Greek κρέας (kreas) 'meat' and σωτήρ (sōtēr) 'preserver'. The two main kinds recognized in industry are coal-tar creosote and wood-tar creosote . The coal-tar variety, having stronger and more toxic properties, has chiefly been used as
4653-403: The compound is metabolized and eliminated from the body, and provide insights into the timing of exposure. Markers of biological effect provide an estimation of exposure based on cellular activities related to the mechanism of action. For example, many studies investigating exposure to pesticides often involve the quantification of the acetylcholinesterase enzyme at the neural synapse to determine
4752-746: The cost side of pesticide use there can be costs to the environment and costs to human health. Pesticides safety education and pesticide applicator regulation are designed to protect the public from pesticide misuse , but do not eliminate all misuse. Reducing the use of pesticides and choosing less toxic pesticides may reduce risks placed on society and the environment from pesticide use. Pesticides may affect health negatively. mimicking hormones causing reproductive problems, and also causing cancer. A 2007 systematic review found that "most studies on non-Hodgkin lymphoma and leukemia showed positive associations with pesticide exposure" and thus concluded that cosmetic use of pesticides should be decreased. There
4851-655: The counter, and usually taken by mouth to assist the bringing up of phlegm from the airways in acute respiratory tract infections. Guaifenesin is a component of Mucinex , Robitussin DAC , Cheratussin DAC , Robitussin AC , Cheratussin AC , Benylin , DayQuil Mucous Control, Meltus, and Bidex 400. Seirogan is a popular Kampo medicine in Japan, used as an anti-diarrheal, and has 133 mg wood creosote from beech, pine, maple or oak wood per adult dose as its primary ingredient. Seirogan
4950-488: The creosote with aqueous mineral acid, although they're also suggested to have antiseptic ability similar to the tar acids. Commercially used creosote is often treated to extract the carbolic acid, naphthalene, or anthracene content. The carbolic acid or naphthalene is generally extracted to be used in other commercial products. In the early 20th century, American-produced creosote oils typically had low amounts of anthracene and high amounts of naphthalene, because when forcing
5049-505: The decline was even steeper, due to the switchover to transgenic Bt corn . Pesticides increase agricultural yields and lower costs. One study found that not using pesticides reduced crop yields by about 10%. Another study, conducted in 1999, found that a ban on pesticides in the United States may result in a rise of food prices , loss of jobs, and an increase in world hunger. There are two levels of benefits for pesticide use, primary and secondary. Primary benefits are direct gains from
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#17327903850825148-562: The discovery of creosote recommended ointments and pills made from tar or pitch to treat skin diseases. Tar water had been used as a folk remedy since the Middle Ages to treat affections like dyspepsia. Bishop Berkeley wrote several works on the medical virtues of tar water, including a philosophical work in 1744 titled Siris: a chain of philosophical reflexions and inquiries concerning the virtues of tar water, and divers other subjects connected together and arising one from another , and
5247-548: The disease, sought to rehabilitate creosote for its use as an antiseptic to treat it. He began a series of trials with Gimbert to convince the scientific community, and claimed a promising cure rate. A number of publications in Germany confirmed his results in the following years. Later, a period of experimentation with different techniques and chemicals using creosote in treating tuberculosis lasted until about 1910, when radiation therapy seemed more promising. Guaiacol, instead of
5346-429: The distillate at a temperature that produces anthracene the soft pitch will be ruined and only the hard pitch will remain; this ruined it for use in roofing purposes (which was common before widespread availability of cheap oil bitumen) and only left a product which wasn't commercially useful. The use of coal-tar creosote on a commercial scale began in 1838, when a patent covering the use of creosote oil to treat timber
5445-502: The environment and human toxicity. DDT has become less effective, as resistance was identified in Africa as early as 1955, and by 1972 nineteen species of mosquito worldwide were resistant to DDT. Total pesticides use in agriculture in 2021 was 3.54 million tonnes of active ingredients (Mt), a 4 percent increase with respect to 2020, an 11 percent increase in a decade, and a doubling since 1990. Pesticides use per area of cropland in 2021
5544-409: The exact biological mechanism which the pesticide disrupts. The modes of action are important for resistance management, and are categorized and administered by the insecticide , herbicide , and fungicide resistance action committees. Pesticides may be systemic or non-systemic. A systemic pesticide moves (translocates) inside the plant. Translocation may be upward in the xylem , or downward in
5643-589: The field is often impractical and many methods are not sensitive enough to detect low-level concentrations. Rapid cholinesterase test kits exist to collect blood samples in the field. Conducting large scale assessments of agricultural workers in remote regions of developing countries makes the implementation of these kits a challenge. The cholinesterase assay is a useful clinical tool to assess individual exposure and acute toxicity. Considerable variability in baseline enzyme activity among individuals makes it difficult to compare field measurements of cholinesterase activity to
5742-402: The first stage of distilling creosote. He recommends cedria to ease the pain in a toothache, as an injection in the ear in case of hardness of hearing, to kill parasitic worms, as a preventive for infusion, as a treatment for phthiriasis and porrigo , as an antidote for the poison of the sea hare , as a liniment for elephantiasis , and as an ointment to treat ulcers both on the skin and in
5841-608: The general population, and many others that are specific to occupational exposures of agricultural workers. Beyond farm workers, estimating exposure to family members and children presents additional challenges, and may occur through "take-home" exposure from pesticide residues collected on clothing or equipment belonging to parent farm workers and inadvertently brought into the home. Children may also be exposed to pesticides prenatally from mothers who are exposed to pesticides during pregnancy. Characterizing children's exposure resulting from drift of airborne and spray application of pesticides
5940-505: The growth of the pesticide industry. During this period, it became increasingly evident that DDT, which had been sprayed widely in the environment to combat the vector, had accumulated in the food chain . It had become a global pollutant, as summarized in the well-known book Silent Spring .Finally, DDT was banned in the 1970s in several countries, and subsequently all persistent pesticides were banned worldwide, an exception being spraying on interior walls for vector control. Resistance to
6039-539: The largest industries. In East Africa, the agricultural industry represents one of the largest sectors of the economy, with nearly 80% of its population relying on agriculture for income. Farmers in these communities rely on pesticide products to maintain high crop yields. Some East Africa governments are shifting to corporate farming , and opportunities for foreign conglomerates to operate commercial farms have led to more accessible research on pesticide use and exposure among workers. In other areas where large proportions of
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#17327903850826138-415: The lungs. He further speaks of cedria being used as the embalming agent for preparing mummies. Pissinum was a tar water that was made by boiling cedria, spreading wool fleeces over the vessels to catch the steam, and then wringing them out. The Pharmacopée de Lyon , published in 1778, says that cedar tree oil is believed to cure vomiting and help medicate tumors and ulcers. Physicians contemporary to
6237-440: The magnitude of the inhibitory effect of organophosphate and carbamate pesticides. Another method of quantifying exposure involves measuring, at the molecular level, the amount of pesticide interacting with the site of action. These methods are more commonly used for occupational exposures where the mechanism of action is better understood, as described by WHO guidelines published in "Biological Monitoring of Chemical Exposure in
6336-412: The method of choice in one third of suicides worldwide, and recommended, among other things, more restrictions on the types of pesticides that are most harmful to humans. A 2014 epidemiological review found associations between autism and exposure to certain pesticides, but noted that the available evidence was insufficient to conclude that the relationship was causal. The World Health Organization and
6435-464: The methyl alcohol produced through distillation) make wood-tar creosote substantially different from coal-tar creosote. Guaiacol is a methyl ether of pyrocatechin , while creosol is a methyl ether of methyl-pyrocatechin, the next homolog of pyrocatechin. Methyl ethers differ from simple phenols in being less hydrophilic, caustic, and poisonous. This allows meat to be successfully preserved without tissue denaturation, and allows creosote to be used as
6534-439: The only active element in wood-tar creosote. In solution, they coagulate albumin , which is a water-soluble protein found in meat, so they serve as a preserving agent, but also cause denaturation. Most of the phenols in the creosote are methoxy derivatives: they contain the methoxy group (−O−CH 3 ) linked to the benzene nucleus. The high level of methyl derivates created from the action of heat on wood (also apparent in
6633-416: The optimized compounds must meet several requirements. In addition to being potent (low application rate), they must show low toxicity to non-target organisms, low environmental impact, and viable manufacturing cost. The cost of developing a pesticide in 2022 was estimated to be 350 million US dollars. It has become more difficult to find new pesticides. More than 100 new active ingredients were introduced in
6732-412: The parent compound or its metabolites in various types of media: urine, blood, serum. Biomarkers may include a direct measurement of the compound in the body before it's been biotransformed during metabolism. Other suitable biomarkers may include the metabolites of the parent compound after they've been biotransformed during metabolism. Toxicokinetic data can provide more detailed information on how quickly
6831-1144: The partial bans on neonicotinoids . Revised 2023 guidance by registration authorities describes the bee testing that is required for new insecticides to be approved for commercial use. In addition to their main use in agriculture , pesticides have a number of other applications. Pesticides are used to control organisms that are considered to be harmful, or pernicious to their surroundings. For example, they are used to kill mosquitoes that can transmit potentially deadly diseases like West Nile virus , yellow fever , and malaria . They can also kill bees , wasps or ants that can cause allergic reactions. Insecticides can protect animals from illnesses that can be caused by parasites such as fleas . Pesticides can prevent sickness in humans that could be caused by moldy food or diseased produce. Herbicides can be used to clear roadside weeds, trees, and brush. They can also kill invasive weeds that may cause environmental damage. Herbicides are commonly applied in ponds and lakes to control algae and plants such as water grasses that can interfere with activities like swimming and fishing and cause
6930-554: The pesticidal activity in a new compound is found in one enantiomer (the eutomer ), the registration and use of the compound as this single enantiomer is preferred. This reduces the total application rate and avoids the tedious environmental testing required when registering a racemate. However if a viable enantioselective manufacturing route cannot be found, then the racemate is registered and used. Insecticides with systemic activity against sucking pests, which are safe to pollinators , are sought after, particularly in view of
7029-399: The plant extracts contained pyrethrum , nicotine , and rotenone among others. The less toxic of these are still in use in organic farming . In the 1940s the insecticide DDT , and the herbicide 2,4-D , were introduced. These synthetic organic compounds were widely used and were very profitable. They were followed in the 1950s and 1960s by numerous other synthetic pesticides, which led to
7128-531: The population rely on subsistence, small-scale farming, estimating pesticide use and exposure is more difficult. Pesticides may exhibit toxic effects on humans and other non-target species, the severity of which depends on the frequency and magnitude of exposure. Toxicity also depends on the rate of absorption, distribution within the body, metabolism, and elimination of compounds from the body. Commonly used pesticides like organophosphates and carbamates act by inhibiting acetylcholinesterase activity, which prevents
7227-497: The quality of tar and temperatures used, but generally, the tar acids won't exceed 5%, the naphthalenes make up 15 to 50%, and the anthracenes make up 45% to 70%. The hydrocarbons are mainly aromatic; derivatives of benzene and related cyclic compounds such as naphthalene , anthracene , phenanthrene , acenaphthene , and fluorene . Creosotes from vertical-retort and low temperature tars contain, in addition, some paraffinic and olefinic hydrocarbons. The tar-acid content also depends on
7326-421: The risk of pesticide poisoning, including dermal absorption walking through fields and applying products, as well as inhalation exposure. There are multiple approaches to measuring a person's exposure to pesticides, each of which provides an estimate of an individual's internal dose. Two broad approaches include measuring biomarkers and markers of biological effect. The former involves taking direct measurement of
7425-460: The same quality of that of traditionally smoked preparations. Sometimes the creosote was diluted in vinegar rather than water, as vinegar was also used as a preservative. Another was to place the meat in a closed box, and place with it a few drops of creosote in a small bottle. Because of the volatility of the creosote, the atmosphere was filled with a vapour containing it, and it would cover the flesh. The application of wood tar to seagoing vessels
7524-645: The second fraction of distillation and is often distilled into what is referred to as " carbolic oil ". [REDACTED] Commercial creosote contains substances from six groups. The two groups occur in the greatest amounts and are the products of the distillation process—the " tar acids ", which distill below 205 °C and consist mainly of phenols, cresols, and xylenols, including carbolic acid—and aromatic hydrocarbons , which divide into naphthalenes , which distill approximately between 205 and 255 °C, and constituents of an anthracene nature, which distill above 255 °C. The quantity of each varies based on
7623-446: The smoke that was produced from burning it was of little inconvenience. By 1879, lamps had been created that ensured a more complete combustion by using compressed air, removing the drawback of the smoke. Creosote was also processed into gas and used for lighting that way. As a fuel, it was used to power ships at sea and blast furnaces for different industrial needs, once it was discovered to be more efficient than unrefined coal or wood. It
7722-607: The source of the tar—it may be less than 3% in creosote from coke-oven tar and as high as 32% in creosote from vertical retort tar. All of these have antiseptic properties. The tar acids are the strongest antiseptics but have the highest degree of solubility in water and are the most volatile; so, like with wood-tar creosote, phenols are not the most valued component, as by themselves they would lend to being poor preservatives. In addition, creosote contains several products naturally occurring in coal—nitrogen-containing heterocycles, such as acridines, carbazoles, and quinolines, referred to as
7821-509: The tar of water gas . Creosote also has been made from pre-coal formations such as lignite , yielding lignite-tar creosote , and peat , yielding peat-tar creosote . The term creosote has a broad range of definitions depending on the origin of the coal tar oil and end-use of the material. With respect to wood preservatives , the United States Environmental Protection Agency (EPA) considers
7920-475: The target organisms listed in the table. A structural class is usually associated with a single mode of action , whereas a mode of action may encompass more than one structural class. The pesticidal chemical ( active ingredient ) is mixed ( formulated ) with other components to form the product that is sold, and which is applied in various ways. Pesticides in gas form are fumigants . Pesticides can be classified based upon their mode of action , which indicates
8019-403: The taste and the creosote oils help act as the preservative. Creosote can be destroyed by treatment with chlorine, either sodium hypochlorite , or calcium hypochlorite solutions. The phenol ring is essentially opened, and the molecule is then subject to normal digestion and normal respiration. The guaifenesin developed by Eldon Boyd is still commonly used today as an expectorant , sold over
8118-636: The term creosote to mean a pesticide for use as a wood preservative meeting the American Wood Protection Association (AWPA) Standards P1/P13 and P2. The AWPA Standards require that creosote "shall be a pure coal tar product derived entirely from tar produced by the carbonization of bituminous coal." Currently, all creosote-treated wood products—foundation and marine pilings , lumber, posts, railroad ties , timbers, and utility poles—are manufactured using this type of wood preservative. The manufacturing process can only be
8217-504: The timber. Alongside the zinc chloride-based "Burnett process" , use of creosoted wood prepared by the Bethell process became a principal way of preserving railway timbers (most notably railway sleepers) to increase the lifespan of the timbers, and avoiding having to regularly replace them. Besides treating wood, it was also used for lighting and fuel. In the beginning, it was only used for lighting needed in harbour and outdoor work, where
8316-454: The title Heavy oil . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Heavy_oil&oldid=945495415 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Creosote Creosote
8415-474: The two were determined only later to be chemically different. All types of creosote are composed of phenol derivatives and share some quantity of monosubstituted phenols, but these are not the only active element of creosote. For their useful effects, coal-tar creosote relies on the presence of naphthalenes and anthracenes , while wood-tar creosote relies on the presence of methyl ethers of phenol. Otherwise, either type of tar would dissolve in water. Creosote
8514-442: The use of pesticides and secondary benefits are effects that are more long-term. Controlling pests and plant disease vectors Controlling human/livestock disease vectors and nuisance organisms Controlling organisms that harm other human activities and structures In 2018 world pesticide sales were estimated to be $ 65 billion, of which 88% was used for agriculture. Generic accounted for 85% of sales in 2018. In one study, it
8613-415: The water to look or smell unpleasant. Uncontrolled pests such as termites and mold can damage structures such as houses. Pesticides are used in grocery stores and food storage facilities to manage rodents and insects that infest food such as grain. Pesticides are used on lawns and golf courses , partly for cosmetic reasons. Integrated pest management , the use of multiple approaches to control pests,
8712-415: The world’s total agricultural land. Pesticides have become more effective. Application rates fell from 1,000–2,500 grams of active ingredient per hectare (g/ha) in the 1950s to 40–100 g/ha in the 2000s. Despite this, amounts used have increased. In high income countries over 20 years between the 1990s and 2010s amounts used increased 20%, while in the low income countries amounts increased 1623%. The aim
8811-478: Was 2.26 kg per hectare (kg/ha), an increase of 4 percent with respect to 2020; use per value of agricultural production was 0.86 kg per thousand international dollar (kg/1000 I$ ) (+2%); and use per person was 0.45 kg per capita (kg/cap) (+3%). Between 1990 and 2021, these indicators increased by 85 percent, 3 percent, and 33 percent, respectively. Brazil was the world's largest user of pesticides in 2021, with 720 kt of pesticides applications for agricultural use, while
8910-579: Was also used industrially for the softening of hard pitch, and burned to produce lamp black . By 1890, the production of creosote in the United Kingdom totaled approximately 29,900,000 gallons per year. In 1854, Alexander McDougall and Robert Angus Smith developed and patented a product called McDougall's Powder as a sewer deodorant; it mainly consisted of carbolic acid derived from creosote. McDougall, in 1864, experimented with his solution to remove entozoa parasites from cattle pasturing on
9009-416: Was discovered, it was the chief active component of medicinal remedies in different cultures around the world. In antiquity, pitches and resins were used commonly as medicines. Pliny mentions a variety of tar-like substances being used as medicine, including cedria and pissinum . Cedria was the pitch and resin of the cedar tree, being equivalent to the oil of tar and pyroligneous acid which are used in
9108-399: Was dropped, until the idea was revived in 1876 by British doctor G. Anderson Imlay , who suggested it be applied locally by spray to the bronchial mucous membrane. This was followed up in 1877 when it was argued for in a clinical paper by Charles Bouchard and Henri Gimbert . Germ theory had been established by Pasteur in 1860, and Bouchard, arguing that a bacillus was responsible for
9207-450: Was estimated that for every dollar ($ 1) that is spent on pesticides for crops results in up to four dollars ($ 4) in crops which would otherwise be lost to insects, fungi and weeds. In general, farmers benefit from having an increase in crop yield and from being able to grow a variety of crops throughout the year. Consumers of agricultural products also benefit from being able to afford the vast quantities of produce available year-round. On
9306-439: Was first discovered in its wood-tar form in 1832, by Carl Reichenbach , when he found it both in the tar and in pyroligneous acids obtained by a dry distillation of beechwood. Because pyroligneous acid was known as an antiseptic and meat preservative , Reichenbach conducted experiments by dipping meat in a dilute solution of distilled creosote. He found that the meat was dried without undergoing putrefaction and had attained
9405-969: Was first used as a gastrointestinal medication by the Imperial Japanese Army in Russia during the Russo-Japanese War of 1904 to 1905. Creomulsion is a cough medicine in the United States, introduced in 1925, that is still sold and contains beechwood creosote. Beechwood creosote is also found under the name kreosotum or kreosote . Polycyclic aromatic hydrocarbons ( PAHs ), alkylated PAHs, benzenes , toluenes , ethylbenzenes , and xylenes ( BTEX ) Phenols, cresols, xylenols, and naphthols Pyridines, quinolines, benzoquinolines, acridines, indolines, and carbazoles Benzothiophenes Dibenzofurans Aniline, aminonaphthalenes, diphenylamines , aminofluorenes, and aminophenanthrenes, cyano-PAHs, benz acridines Coal-tar creosote
9504-413: Was practiced through the 18th century and early 19th century, before the creosote was isolated as a compound. Wood-tar creosote was found not to be as effective in wood treatments, because it was harder to infuse the creosote into the wood cells, but still experiments were done, including by many governments, because it proved to be less expensive on the market. Even before creosote as a chemical compound
9603-422: Was soon commonly sold under the name "creosote", and the scarcity of wood-tar creosote in some places led chemists to believe that it was the same substance as that described by Reichenbach. In the 1840s, Eugen Freiherr von Gorup-Besanez , after realizing that two samples of substances labelled as creosote were different, started a series of investigations to determine the chemical nature of carbolic acid, leading to
9702-615: Was soon determined to be the same compound. There was no clear view on the relationship between carbolic acid and creosote; Runge described it as having similar caustic and antiseptic properties, but noted that it was different, in that it was an acid and formed salts. Nonetheless, Reichenbach argued that creosote was also the active element, as it was in pyroligneous acid. Despite evidence to the contrary, his view held sway with most chemists, and it became commonly accepted wisdom that creosote, carbolic acid, and phenylhydrate were identical substances, with different degrees of purity. Carbolic acid
9801-413: Was taken out by inventor John Bethell . The "Bethell process"—or as it later became known, the full-cell process —involves placing wood to be treated in a sealed chamber and applying a vacuum to remove air and moisture from wood "cells". The wood is then pressure-treated to imbue it with creosote or other preservative chemicals, after which vacuum is reapplied to separate the excess treatment chemicals from
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