Patty's Toxicology最新文献

{"title":"Alkaline Materials: Sodium, Potassium, Cesium, Rubidium, Francium, and Lithium","authors":"R. Jefferson","doi":"10.1002/0471435139.TOX046.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX046.PUB2","url":null,"abstract":"Alkaline materials cause irritation and corrosion of body tissues and the most commonly encountered alkaline salts are of potassium and sodium. The hydroxides of potassium and sodium being the most hazardous. The eyes are particularly susceptible to alkaline materials leading to significant tissue damage. Exposures in the workplace should be minimized using appropriate risk assessment protocols and occupational hygiene hierarchy of control measures. It is essential that employees at risk have focused safety training. Lithium compounds (carbonate and citrate) have been used widely for a number of years for the treatment of mania and bipolar disorders. The main industrial use of lithium is in lithium stearatum form, as a lubricant grease thickener in automotive applications. The toxicity of cesium is mainly due to its radioactive isotopes. Sodium metasilicate is markedly corrosive and penetrating and initial clinical manifestations of acute ingestion can include dysphagia, drooling, pain and hematemesis. Trisodium phosphate is used as a cleaning agent, food additive, stain remover and degreaser. Sodium peroxide is used as an oxidizing agent and is used as an oxygen source by reacting with carbon dioxide to produce oxygen and sodium carbonate; it is thus particularly useful in scuba gear, submarines, etc. The hazard of sodium hydroxide for the environment is caused by the hydroxyl ion. The chapter discusses properties, uses, toxic effects and standards, regulations, or guidelines of exposure of various alkaline materials. \u0000 \u0000 \u0000Keywords: \u0000 \u0000hyperkalemia; \u0000Corrosive; \u0000burns; \u0000hypokalemia; \u0000hyponatremia; \u0000cardiac arthymias","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75588656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arsenic, Antimony, and Bismuth","authors":"B. Fowler, Emily F. Madden, Selene Chou","doi":"10.1002/0471435139.TOX036.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX036.PUB2","url":null,"abstract":"The production of arsenic usually occurs as a by-product of copper smelting, and is approximately in the range of 50,000–100,000 tons per year but this is a rough estimate based on previous global estimates by WHO and the impact of increasing use of As in the global semiconductor industry. This element is used for a variety of industries including glass manufacturing, wood preservatives, metal alloys, pesticides and in the manufacture of semiconductors as a dopant for silicon-based semiconductors or the production of III-V semiconductors such a gallium arsenide and indium arsenide. \u0000 \u0000 \u0000 \u0000Fowler's solution (potassium arsenite-As3+) had been used in the past to treat a variety of clinical illnesses such as leukemia and skin disorders such as psoriasis and bronchial asthma but was supplanted by more modern chemotherapeutic agents during the last 20 years. More recently, As3+ has been effectively used to treat promyelocytic leukemia. \u0000 \u0000 \u0000 \u0000Human exposure to inorganic arsenic may occur via air, food, and water. Persons consuming seafood generally have higher total intakes of arsenic, but the chemical forms of arsenic are primarily arsenobetaine and other methylated species of relatively low toxic potential. \u0000 \u0000 \u0000 \u0000Arsenic is a general systemic poison whose toxic and medicinal properties have been known for several thousand years. The carcinogenic properties of inorganic arsenicals in humans have been known for several hundred years. \u0000 \u0000 \u0000 \u0000Sb as an element is a brittle, flaky, crystalline (hexagonal) silver-white metal. It does not react with air at room temperature but burns brightly when heated, and forms white fumes. It is a poor conductor of electricity and heat. Antimony occurs in tri- (+3) and pentavalent (+5) compounds and is found in the earth's crust mostly associated with sulfur as stibnite and in ores associated with arsenic. Antimony is a group VA element of the periodic table and it has many of the same chemical and biological properties as the element arsenic. \u0000 \u0000 \u0000 \u0000Stibine gas is odorless. Exposure to antimony at high levels may result in a variety of adverse health effects. For example, breathing high levels of antimony and some of its compounds can irritate the eyes and lungs and can cause problems with the heart, lungs, and stomach. \u0000 \u0000 \u0000 \u0000Historically, antimony compounds were used as emetics and expectorants. Recently, antimony compounds, such as tartar emetic and sodium stibogluconate, are used as antihelminthic and antiprotozoic drugs in treating parasitic diseases and infections. It plays no role in nutrition and is a nonessential element. \u0000 \u0000 \u0000 \u0000Bismuth is a brittle, white, crystalline metal that has a pinkish tint. It is the most diamagnetic of all metals, and its thermal conductivity is lower than any metal except mercury. In addition, bismuth has high electrical resistance and the highest Hall effect of any metal. Inorganic salts of bismuth are poorly water soluble; solubility is influenced by the acidity of the medium and","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73998130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zinc and Cadmium Compounds","authors":"M. Jakubowski","doi":"10.1002/0471435139.TOX029.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX029.PUB2","url":null,"abstract":"Zinc is widely distributed in nature. The methods for the determination of zinc in different environmental media (air, soil, water, waste, plants) have been reviewed. Zinc screenings are widely applied in the clinical practice. Zinc is essential for humans and animals. It is necessary for the function of numerous enzymes. The toxic effects of zinc have been associated with excess exposure. Zinc acetate has been found to be the most toxic of the compounds tested so far. It has been noticed that excessive zinc addition to food or water has resulted in a variety of systemic effects in the hematological and gastrointestinal systems. Genotoxicity studies conducted in a variety of test systems have failed to provide evidence for the mutagenicity. Zinc is relatively nontoxic, particularly if taken orally, except for the corrosive properties of some salts. The present chapter discusses chemical and physical properties, exposure assessment, guidelines of exposure and clinical cases for various zinc and zinc compounds. \u0000 \u0000 \u0000Keywords: \u0000 \u0000cysteine-rich intestinal protein; \u0000adult respiratory distress syndrome; \u0000tubular proteinuria; \u0000alkaline phosphatase","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74898359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphorus, Selenium, Tellurium, and Sulfur","authors":"Barbara Malczewska‐Toth","doi":"10.1002/0471435139.TOX044.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX044.PUB2","url":null,"abstract":"Phosphorus and sulfur are elements 15 and 16 in the periodic chart and selenium and tellurium are in the same group as sulfur. Sulfur was not covered in the previous edition, but sulfur and its compounds have been added in this edition because of the importance of sulfur compounds. \u0000 \u0000 \u0000 \u0000Elemental phosphorus is produced as a by-product or intermediate in the production of phosphate fertilizer. Environmental contamination with phosphorus results from its manufacture into phosphorus compounds and during the transport and use of these compounds. In the manufacturing process, phosphate rock containing the mineral apatite (tricalcium phosphate) is heated and elementary phosphorus is liberated as a vapor. Phosphorus is used to manufacture explosives, incendiaries, smoke bombs, chemicals, rodenticides, phosphor bronze, and fertilizer. The use of phosphate fertilizers results in increased nutrients in fresh water and is a major source of environmental pollution. \u0000 \u0000 \u0000 \u0000Phosphorus exists in several allotropic forms: white (or yellow), red, and black (or violet). The last is of no industrial importance. Elemental yellow phosphorus extracted from bone was used to make “strike anywhere” matches. In 1845, the occupational disease “phossy jaw,” a jaw bone necrosis, was recognized in workers who manufactured such matches. A prohibitive tax imposed in 1912 on matches made from yellow phosphorus led to the use of less toxic materials, red phosphorus and phosphorus sesquisulfide. The United States appears to have lagged behind European countries in that signatories of the Berne Convention of 1906 agreed not to manufacture or import matches made with yellow phosphorus. Occasional injuries continued to result from using yellow phosphorus to manufacture fireworks until 1926, when an agreement was reached to discontinue the use of yellow phosphorus for this purpose. \u0000 \u0000 \u0000 \u0000The world production of elemental phosphorus exceeds 1,000,000 metric ton. It is manufactured either in electric or blast furnaces. Both depend on silica as a flux for the calcium present in the phosphate rock. Nearly all of the phosphorus produced is converted into phosphoric acid or other phosphorus compounds. \u0000 \u0000 \u0000 \u0000Red phosphorus does not ignite spontaneously but may be ignited by friction, static electricity, heating, or oxidizing agents. Handling it in an aqueous solution helps prevent fires. \u0000 \u0000 \u0000 \u0000Phosphorus (white yellow) can be absorbed through the skin, respiratory tract, and gastrointestinal (GI) tract. Experimental investigations on rats show the highest retention 5 days after oral administration in the liver, skeletal muscle, GI tract, blood, and kidney. Phosphorus is converted to phosphates in the body. Urinary excretion, the chief mode of elimination, is largely in the form of organic and inorganic phosphates. \u0000 \u0000 \u0000 \u0000Selenium (Se), a nonmetallic element of the sulfur group, is widely distributed in nature. It is obtained along with tellurium as a by-product of metal ore refining, ch","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85170551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gallium, Indium, and Thallium","authors":"G. Repetto, A. D. Peso","doi":"10.1002/0471435139.TOX032.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX032.PUB2","url":null,"abstract":"The chemical elements gallium, indium, and thallium belong to group IIIA in the periodic table. Unlike other metals, such as lead and arsenic, which have been featured prominently in toxicologic folklore since antiquity, they are relative newcomers, discovered from 1861 to 1876. Since then, thallium has developed a well-deserved reputation for its toxic properties and is recognized as a potent accidental, occupational, and environmental poison, with incidence in cases of homicide and suicide. Although gallium and indium are not as toxic as thallium, their production and industrial use represent an important source of exposure, particularly in the increasing manufacture of semiconductor electronic devices. Gallium compounds particularly produce pulmonary toxicity. Indium compounds induce pulmonary toxicity and also nephrotoxicity, hepatotoxicity, and developmental toxicity, whereas thallium compounds act as general poisons. Some compounds are also capable of altering various cellular defense mechanisms involved in carcinogenesis. However, many aspects of the toxicity of individual compounds in human beings, including toxicokinetics, mechanisms of action, teratogenic potential, and the best treatment, remain to be elucidated. \u0000 \u0000 \u0000Keywords: \u0000 \u0000Gallium; \u0000Indium; \u0000Thallium; \u0000Gallium compounds; \u0000Indium compounds; \u0000Thallium compounds; \u0000Physical and Chemical properties; \u0000Production; \u0000Use; \u0000Exposure assessment; \u0000Toxic effects; \u0000Radiopharmaceuticals; \u0000Cancers; \u0000Cancer treatment; \u0000Toxic effects; \u0000Hodgkin's disease; \u0000Non-Hodgkin's lymphoma; \u0000Standards; \u0000Guidelines; \u0000Regulations; \u0000Environmental impact; \u0000Aquatic ecosystems; \u0000Alopecia","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79391545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chromium, Molybdenum, and Tungsten","authors":"S. Langård, D. Lison","doi":"10.1002/0471435139.TOX038.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX038.PUB2","url":null,"abstract":"The physical and chemical characteristics of chromium and some of its compounds are summarized. \u0000 \u0000 \u0000 \u0000The term chromium is derived from the Greek word for color, because most chromium compounds are brightly pigmented. The element chromium was discovered in 1798 by N. L. Vauquelin, but it had already been used in swords by the Hittits about 1300 b.c. Chromium occurs in nature in bound-form chromite ore, which is the only chromium ore of any importance, and it makes up 0.1–0.3 ppm of the earth's crust. The red color of rubies and green color of emeralds, serpentine, and chrome mica are produced by chromium. \u0000 \u0000 \u0000 \u0000Chromium metal is prepared by reducing the ore in a blast furnace with carbon (coke) or silicon to form an alloy of chromium and iron called ferrochrome, which is used as the starting material for the many iron-containing alloys that employ chromium. Chromium to be used in iron-free allloys is obtained by reduction or electrolysis of chromium compounds. Chromium is difficult to work in the pure metal form; it is brittle at low temperatures, and its high melting point makes it difficult to cast. \u0000 \u0000 \u0000 \u0000The use of chromium in stainless steel (18%+) is a major use of the element. \u0000 \u0000 \u0000 \u0000The U.S. National Occupational Exposure Survey estimated that a total of about 200,000 workers, including about 30,000 women, were potentially exposed to hexavalent chromium compounds. The typical airborne concentrations in various industrial operations are given; however, the combustion of coal and oil is the largest single source of air pollution. \u0000 \u0000 \u0000 \u0000Chromium in the trivalent form is an essential trace element to humans. It is involved in the metabolism of glucose. Chromium deficiency may result in impaired glucose tolerance, peripheral neuropathy, and elevated serum insulin, cholesterol, and triglycerides, similar to those symptoms observed in diabetic patients. \u0000 \u0000 \u0000 \u0000Molybdenum is a dark-gray, or a black powder with a metallic luster and a chemical element of the second transition series. The name is derived from the Greek molybdos, meaning “lead.” In 1778 Carl Scheele of Sweden recognized molybdenite as a distinct ore of a new element. Hjelm in 1782 prepared an impure form of the metal. \u0000 \u0000 \u0000 \u0000Free molybdenum does not occur in nature, but it is extracted from molybdenite, wulfenite, and powellite and is recovered as a by-product of copper and tungsten mining operations. Molybdenum is found in many parts of the world, but relatively few deposits are rich enough to warrant recovery costs. By far the largest and richest deposits occur in the western hemisphere, with the United States contributing the major share. \u0000 \u0000 \u0000 \u0000Molybdenite concentrates are roasted to produce technical-grade oxide, considerable amounts of which are used directly in steel; the rest is converted to other molybdenum products. MoO3 of higher purity is made by sublimation of the technical-grade oxide or from (NH4)2MoO4. FerroMo is made from the oxide by ignition with aluminum, iron","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81724403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Lanthanides, Rare Earth Elements","authors":"W. Wells, Vickie L. Wells","doi":"10.1002/0471435139.TOX043.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX043.PUB2","url":null,"abstract":"The lanthanides (or lanthanons) are a group of 15 elements of atomic numbers from 57 through 71 in which scandium (atomic number 21) and yttrium (atomic number 39) are sometimes included. The lanthanide series proper is that group of chemical elements that follow lanthanum in its group IIIB column position of the periodic table. Their distinguishing atomic feature is that they fill the 4f electronic subshell. Actually, only those elements with atomic numbers 58–71 are lanthanides. Most chemists also include lanthanum in the series because, although it does not fill the 4f subshell, its properties are very much like those of the lanthanides. The elements scandium and yttrium are also known as the “rare earths” because they were originally discovered together with the lanthanides in rare minerals and isolated as oxides, or “earths.” Collectively, these metals are also called rare earth elements (REEs). In comparison with many other elements, however, the rare earths are not really rare, except for promethium, which has only radioactive isotopes. Yttrium, lanthanum, cerium, and neodymium are all more abundant than lead in the earth's crust. All except promethium, which probably does not occur in nature, are more abundant than cadmium. The relative abundance and atomic numbers are provided. The more common lanthanide compounds are listed in Section 1. \u0000 \u0000 \u0000 \u0000Scandium is a silvery white metallic chemical element, the first member of the first transition-metal series in the periodic table. The name is derived from Scandinavia, where the element was discovered in the minerals euxenite and gadolinite. In 1876, L. F. Nilson prepared about 2 g of high purity scandium oxide. It was subsequently established that scandium corresponds to the element “ekaboron,” predicted by Mendeleyev on the basis of a gap in the periodic table. Scandium occurs in small quantities in more than 800 minerals and causes the blue color of aquamarine beryl. \u0000 \u0000 \u0000 \u0000Yttrium is one of the four chemical elements (the others are erbium, terbium, and ytterbium) named after Ytterby, a village in Sweden that is rich in unusual minerals and rare earths. Yttrium is a metal with a silvery luster and properties closely resembling those of rare earth metals. It is the first member of the second series of transition metals. Yttrium is found in several minerals and is produced primarily from the ore material xenotime. \u0000 \u0000 \u0000 \u0000Lanthanum is a white, malleable metal; it is the first member of the third series of transition metals, and the first of the rare earths. Lanthanum is found with other lanthanides in the ore minerals monazite, bastnaesite, and xenotime, and in other minerals. It was discovered in 1839 by the Swedish chemist Carl G. Mosander. Scientists have created many radioactive isotopes of lanthanum. \u0000 \u0000 \u0000Keywords: \u0000 \u0000cerium; \u0000chlorides; \u0000dysprosium; \u0000erbium; \u0000europium; \u0000gadolinium; \u0000kidneys; \u0000lanthanides; \u0000lanthanum; \u0000liver; \u0000lungs; \u0000monazite; \u0000neodymium; \u0000nitrates; \u0000oxides; \u0000scandium; \u0000","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74826052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Silver and Gold","authors":"A. Lansdown","doi":"10.1002/0471435139.TOX026.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX026.PUB2","url":null,"abstract":"Silver and gold are transitional metals and exhibit different chemical properties. They have distinctive uses in industry, commercial applications and in medical science. The World Health Organization and various national regulatory authorities recognize that occupational exposure to silver and many other metals in the workplace pose significant health risks. In the case of silver, argyria and argyrosis with profound discolorations of the skin and eyes present a major risk associated with chronic exposure to silver. Selected clinical cases are documented to illustrate complications that arise in the use of silver. Gold dust is expected as a contaminant in the atmosphere close to mining areas, but in view of their high density, particles, can be expected to settle rapidly and present minimal risk of inhalation by workers, but appreciably greater risks have been associated with silica, mercury and cyanide in gold workers. Neutron activation analysis has been described for determination of gold in blood following clinical or occupational exposure to the metal. The present chapter discusses properties, production, uses, exposure assessment, toxic effects, and several clinical cases of these transitional metals. \u0000 \u0000 \u0000Keywords: \u0000 \u0000argyrosis; \u0000metallic silver; \u0000hypogeusia; \u0000chrysiasis","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83639990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vanadium, Niobium, and Tantalum","authors":"K. Rydzyński, D. Pakulska","doi":"10.1002/0471435139.TOX037.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX037.PUB2","url":null,"abstract":"Vanadium (V), niobium (Nb), and tantalum (Ta) are transition metals from group V. They have partly filled d shells, so they are defined as transition elements. Vanadium and niobium are widely distributed in Earth's crust, but there are few concentrated deposits of these elements. Tantalum is less abundant in the Earth's crust; it occurs in the same minerals as niobium, and their separation is complex. The main commercial sources of both the metals are the columbite–tantalite series of minerals [(Fe/Mn)(Nb/Ta)2O6], with various Fe/Mn and Nb/Ta ratios. \u0000 \u0000 \u0000 \u0000Pure or almost pure elements in massive form are gray-colored, ductile metals with high (V, Ta) or moderate (Nb) hardness and very high melting points. Vanadium group elements are resistant to chemicals and this resistance increases with the atomic number. At room temperature, they are not affected by air, water, or alkalies. Vanadium dissolves in oxidizing acids (e.g., nitric acid, concentrated sulfuric acid, aqua regia) and in hydrofluoric acid. Niobium and tantalum can be dissolved by HNO3/HF mixture and are slowly attacked by hydrofluoric acid. All these elements dissolve very slowly in fused alkalies, producing salts, vanadates, niobates, or tantalates, as well as hydrogen. Vanadium, niobium, and tantalum pentaoxides are the main products of air oxidation at high temperatures; vanadium can also form trioxide and tetraoxide under these conditions. At elevated temperatures, metals combine with some nonmetals, for example, with hydrogen, nitrogen, carbon, and silica, giving compounds, many of which are interstitial and nonstoichiometric. All these elements have five valence electrons; however, electronic configuration of valence orbitals is different. \u0000 \u0000 \u0000 \u0000Vanadium compounds are the most toxic among all the three elements; tantalum compounds are practically nontoxic. Reported LC50 values for vanadium pentoxide (V2O5) are between 70 and 200 mg/m3. There are no data on niobium. Vanadium compounds are moderately toxic when given orally, and their toxicity increases with the oxidation states. Reported LD50 values are in the tens to hundreds of mg/kg body weight. Niobium and tantalum compounds given orally are practically nontoxic; reported LD50 values are in several thousand mg/kg body weight. All elements and their compounds are absorbed from the respiratory tract and eliminated through the kidney. Their absorption from the gastrointestinal (GI) tract is poor. They are distributed to internal organs, and there are data indicating that vanadium and tantalum might accumulate in bone. Vanadium and niobium have an irritant effect on mucous membranes and skin. Therefore, irritant effects on the upper respiratory tract and lungs are observed when animals are exposed by inhalation to vanadium and niobium compounds; however, vanadium compounds have stronger effects. \u0000 \u0000 \u0000 \u0000Many studies have documented the mitogenic potential of vanadium compounds. Results of mutagenicity studies of vanadium are confl","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83179018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ketones of Four Or Five Carbons","authors":"J. O’Donoghue","doi":"10.1002/0471435139.TOX075.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX075.PUB2","url":null,"abstract":"A ketone is an organic compound containing a carbonyl group (CO) attached to two carbon atoms and can be represented by the general formula \u0000 \u0000 \u0000 \u0000Several billion pounds of ketones are produced annually for industrial use in the United States. Those with the highest production volumes include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, isophorone, mesityl oxide, and acetophenone. Common methods used to manufacture ketones include aliphatic hydrocarbon oxidation, alcohol dehydration with subsequent oxidation, dehydrogenation of phenol, alkyl aromatic hydrocarbon oxidation, and condensation reactions. \u0000 \u0000 \u0000 \u0000Ketones are used because of their ease of production, low manufacturing cost, excellent solvent properties, and desirable physical properties such as low viscosity, moderate vapor pressure, low to moderate boiling points, high evaporation rates, and a wide range of miscibility with other liquids. The low-molecular-weight aliphatic ketones are miscible with water and organic solvents, whereas the high-molecular-weight aliphatic and aromatic ketones are generally immiscible with water. Most ketones are chemically stable. The exceptions are mesityl oxide, which can form peroxides, and methyl isopropenyl ketone, which polymerizes. Most ketones are generally of low flammability. \u0000 \u0000 \u0000 \u0000Ketones are commonly used in industry as solvents, extractants, chemical intermediates, and, to a lesser extent, flavor and fragrance ingredients. Ketones have also been reported in the ambient air, in wastewater treatment plants, and in oil field brine discharges. \u0000 \u0000 \u0000Keywords: \u0000 \u00003-Butyne-2-one; \u0000diacetyl; \u0000environmental samples; \u0000ketone; \u0000methyl ethyl ketone; \u0000methyl isopropenyl ketone; \u0000methyl isopropyl ketone; \u0000methyl-n-propyl ketone; \u00003-pentyne-2-one; \u00002,4-pentanedione","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73106919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}