Patty's Toxicology最新文献

{"title":"Esters of Carbonic and Orthocarbonic Acid, Organic Phosphorous, Monocarboxylic Halogenated Acids, Haloalcohols, and Organic Silicon","authors":"W. A. Toscano, K. Coleman","doi":"10.1002/0471435139.TOX081.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX081.PUB2","url":null,"abstract":"This chapter covers (1) esters of carbonic and orthocarbonic acid, (2) esters of organic phosphorous compounds, (3) esters of monocarboxylic halogenated acids, alkanols, or haloalcohols, and (4) organic silicon esters. Other classes of esters are summarized in Chapters 57 and 58. Refer to the Introduction in Chapter 57 for a more detailed overview of general properties of esters. \u0000 \u0000 \u0000 \u0000Unfortunately, as shown in the two prior chapters, mainly fragmented toxicological evaluations are available for esters. Most of these esters are characterized by low toxicity. Indeed, as expressed in Chapter 57, lethal dose (e.g., LD50) values are frequently difficult or impractical to measure. Localized dermal irritation is one common effect characteristic of exposures to most organic solvents. Few esters are readily absorbed, but there are exceptions, such as tri-o-cresyl phosphate (TOCP). Several of the halogenated derivatives, such as ethylchloro- and ethylbromo-, are potent lacrimators. Ethyl fluoroacetate and fluoroacetic acid exhibit about the same mode of action, which may indicate that the acetate is rapidly hydrolyzed and metabolized in the mammalian system. The unsaturated carbonates are also associated with high lacrimatory activity. \u0000 \u0000 \u0000 \u0000TOCP is an example of an ester that can cause neuropathy in a variety of animal species. The initial weakness and paralysis are normally reversible in early stages, but repeated or massive assaults result in demyelination of the nerve fibers. The mechanism of action is not yet certain, but it appears to involve phosphorylation of proteins. Only selected phosphates exhibit neuropathic effects, including diisopropyl fluorophosphorate and N,N′-diisopropyl phosphorodiamidic fluoride. \u0000 \u0000 \u0000 \u0000As was expressed in Chapter 57, industrial hygiene evaluation of esters involves collecting and analyzing air samples to determine their airborne concentrations. Published industrial hygiene air sampling and analytical methods, however, are unavailable for most esters. In relation, there are few occupational exposure and biological limits. A list of ester compounds covered in this chapter that have industrial hygiene sampling and analytical methods are presented here along with their respective occupational exposure limits, established by the American Conference of Governmental Industrial Hygienists (ACGIH), the Occupational Safety and Health Administration (OSHA), and the National Institute for Occupational Safety and Health (NIOSH). As stated in Chapter 57, since sampling and analytical methods and occupational exposure limits are subject to periodic revision, the reader is encouraged to refer to current publications of ACGIH, OSHA, and NIOSH. \u0000 \u0000 \u0000Keywords: \u0000 \u0000alkyl phosphates; \u0000alkyl phosphines; \u0000aryl phosphates; \u0000aryl phosphines; \u0000bromoesters; \u0000carbonates; \u0000chloroesters; \u0000cyclic carbonates; \u0000esters of organic phosphorus compounds; \u0000fluroesters; \u0000haloalcohols; \u0000halogenated phosphate esters; \u0000organic silicon esters; \u0000ortho acid e","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81577084","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":"Aldehydes and Acetals","authors":"M. Borchers","doi":"10.1002/0471435139.TOX073.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX073.PUB2","url":null,"abstract":"More than 300 aldehydes occur in foods, water, and air. Due to the electrophilicity of the carbonyl carbon, particularly when proximal to a carbon–carbon double bond, aldehydes react with thiols and amines to form protein–protein, DNA–protein, and DNA–DNA cross-links. Despite their potential for causing cell damage, toxicological and exposure data for a large number of aldehydes are lacking. Inhalation and ingestion studies have demonstrated that a number of aldehydes are irritants and can induce tumors in animal models. Formaldehyde, which is a suspected carcinogen, is the most widely studied of these compounds. The physicochemical properties of saturated aldehydes are summarized. Toxicological and health effects are given. \u0000 \u0000 \u0000Keywords: \u0000 \u0000acetals; \u0000aliphatic dialdehydes; \u0000aromatic aldehydes; \u0000Clean Air Act; \u0000EPA; \u0000flavoring agents; \u0000formaldehyde; \u0000halogenated aldehydes; \u0000heterocyclic aldehydes; \u0000saturated aliphatic aldehydes; \u0000unsaturated aliphatic aldehydes; \u0000urea–formaldehyde resins","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85994959","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":"Petroleum, Coal Tar, and Related Products","authors":"R. Niemeier","doi":"10.1002/0471435139.TOX022.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX022.PUB2","url":null,"abstract":"The chemical composition of coal tar, coal tar pitch, and related materials is complex and variable. The estimated number of compounds present in these complex mixtures is in thousands. Because of variation in source materials and manufacturing processes, including different temperatures and times of carbonization, no two coal tars or pitches are chemically identical, and their toxicity may differ with their origin. In general, however, approximately 80% of the total carbon present in coal tars exists in aromatic form. \u0000 \u0000 \u0000 \u0000Benzo[a]pyrene (B[a]P) is probably the most potent, widespread occupational carcinogen in coal tar, coal tar pitch and its volatiles, coke oven emissions, and creosote, all of which have corresponding work exposure standards; however, there is no occupational workplace standard for B[a]P in the United States. B[a]P may account for more than 75% of the carcinogenic activity of coal tar pitch fume condensate. Individuals who work in tarring facilities, roofing operations, power plants, and asphalt and coke manufacturing facilities may be exposed to benzo[a]pyrene and related PAHs. These mixtures may differ qualitatively and quantitatively. \u0000 \u0000 \u0000 \u0000Coal tar is completely or nearly completely soluble in benzene and nitrobenzene and it is partially soluble in acetone, carbon disulfide, chloroform, diethyl ether, ethanol, methanol, petroleum ether, hexane, and sodium hydroxide solution, and slightly soluble in water. It has a characteristic naphthalene-like odor. Coal tar is heavier than water and on ignition it burns with a reddish, luminous, and very sooty flame. Coal tar fumes are highly flammable and are easily ignited by heat, sparks, or flames. Vapors are heavier than air. They may travel to a source of ignition and flash back and may form explosive mixtures with air. Vapors will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion is a potential hazard indoors, outdoors, or in sewers. Some may polymerize explosively when heated or involved in a fire. Runoff to a sewer may create a fire or explosion hazard. Containers may explode when heated. Coal tar may be transported hot. \u0000 \u0000 \u0000 \u0000The greatest complexity occurs when toxicity is based on the effects of a class of compounds or of a material of a certain physical description. Some polynuclear aromatic hydrocarbons (PNAs) and polycyclic aromatic hydrocarbons (PAHs) are carcinogens of varying potency, and they usually exist in mixtures with other PNAs/PAHs and with compounds (activators, promoters, and inhibitors) that modify their activity. Analysis of each individual compound is very difficult and when done does not yield a clear answer. Given the complexity of the mixture of biologically active agents and their interactions, a calculated equivalent dose would have little accuracy. In these instances, it is common to measure some quantity related to the active agents and to base the occupational exposure limit on that index. An oc","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76050914","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":"Synthetic Polymers: Polyesters, Polyethers, Polysulfones, and Other Polymers","authors":"Amy Benson","doi":"10.1002/0471435139.TOX092.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX092.PUB2","url":null,"abstract":"Commercial use of polyester resins dates from the early twentieth century, when alkyd resins were first used in surface coatings. The polyesters are found today as fibers, films, laminating resins, molding resins, and engineering plastics. Many of the high molecular weight polyethers are used as engineering plastics, as are the polysulfides and the polysulfones. Important properties of these compounds and production data for the general categories are provided. Processing techniques vary widely and are discussed in the sections in this chapter. \u0000 \u0000 \u0000 \u0000Although toxicity data for some of these polymers are limited, information is discussed in the sections in this chapter. In many cases, the finished polymers are associated with low toxicity. However, some chemicals within the finished products have been known to migrate from the polymers (although usually in small amounts). Further, some of the polymers described in this chapter are used in biomedical equipment, including grafts and other implants, dialysis membranes, or as vehicles for intravenous injections, and there may be toxicity associated with these uses. For specific medical applications, any risks should be weighed against benefits derived from the products. Consultation with medical professionals is necessary before deciding on whether to use particular devices. \u0000 \u0000 \u0000 \u0000Certainly some of the highest potentials for concern associated with these polymers are for workers at manufacturing or processing sites. Workers may be exposed to volatile chemicals (e.g., monomers, flame retardants, additives) generated during processing of flammable solvents, elevated temperatures, or fires. Workers may also be exposed to dust or particulates generated in the manufacturing and processing of polyester fibers. Finally, explosion hazards might be possible where static charges are generated (e.g., during physical processing of polyester films over rollers) where flammable materials are used. \u0000 \u0000 \u0000 \u0000Industrial hygiene concerns with these polymers depend on the type of resin. Examples of such concerns include the following: significant quantities of styrene may be released during the fabrication of unsaturated polyester resins; particulates that have biologically significant consequences when inhaled in large amounts may be generated in the manufacturing and processing of polyester fibers; processing of polyoxymethylene in a poorly ventilated space may release biologically significant amounts of formaldehyde into the adjacent atmosphere; or sulfur-containing engineering resins may yield hydrogen sulfide or sulfur dioxide if heated to decomposition temperatures. The chemical inputs typically used to synthesize each of the polymers as well as relevant additives are discussed in the sections in this chapter. Toxicity data for most of these inputs can be found in other chapters of this edition of Patty's Industrial Hygiene and Toxicology. \u0000 \u0000 \u0000 \u0000No specific standards are known that pertain to ordinary industrial ","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87970626","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":"Human Health Effects of Nonionizing Electromagnetic Fields","authors":"D. Carpenter","doi":"10.1002/0471435139.TOX100.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX100.PUB2","url":null,"abstract":"The present chapter deals with that portion of the electromagnetic spectrum that has lower energy and longer wavelengths than the infrared, including the extra low frequency (ELF) magnetic fields from electricity and radiofrequency (RF) fields used in communication. The energies at these frequencies are not sufficient to directly break chemical bonds, and the question to be examined is whether they have sufficient energy to cause human disease by other mechanisms, particularly at intensities that do not cause measurable heating. Present research indicates a consistent pattern of elevated risk of cancer, especially leukemia, and some neurodegenerative diseases at ELF magnetic field levels commonly found in residences and occupations. The relationship between childhood magnetic field exposure and brain cancer is also reviewed. Human studies and meta-analyses of research of mobile phone use show a consistent and elevated risk of brain cancer and acoustic neuroma upon intense and long-term use. International and national standards of human exposure to ELF and RF frequencies are presented and found to be inadequate for the protection of human health. The evidence of human harm from excessive exposure to both ELF and RF is stronger and more consistent for cancer and neurodegenerative diseases than is commonly recognized. While there is less strong reproducibility and consistency for some other proposed health outcomes, this indicates only the need for more research with better exposure assessment. \u0000 \u0000 \u0000Keywords: \u0000 \u0000Leukemia; \u0000brain cancer; \u0000acoustic neuroma; \u0000Alzheimer's disease; \u0000amyotrophic lateral sclerosis; \u0000electromagnetic fields (EMFs); \u0000mutations; \u0000radiofrequency; \u0000Universal Mobile Telecommunications System","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82933674","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":"Dibenzo-p-Dioxins: 2,3,7,8-Tetrachlorodibenzo-p-Dioxin","authors":"S. Hee","doi":"10.1002/0471435139.TOX065.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX065.PUB2","url":null,"abstract":"Chlorinated dibenzo-para-dioxins or dibenzo-p-dioxins (CDDs) are a class of compounds with 75 possible congeners. When the CDDs contain more than one chlorine they are termed polychlorinated dibenzo-p-dioxins (PCDDs). Most of the information is for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), the most toxic congener. The bulk of the material in this chapter relates to this compound. The toxic PCDD congeners are substituted with chlorines in the 2,3,7, and 8 positions. The least toxic congeners are the monochlorinated PCDDs and octachlorodibenzo-p-dioxin [CAS RN 3268-87-9], the fully chlorinated PCDD. PCDDs often are accompanied by the dibenzofuran analogs, the polychlorinated dibenzofurans (PCDFs), and the diphenyl ether analogs, the polychlorinated diphenyl ethers (PCDPEs). The cumulative toxicity of the toxic congeners of polychlorinated biphenyls (PCBs), PCDDs, PCDFs, and PCDPEs in a sample is expressed through the 2,3,7,8-TCDD toxicity equivalent (TEQ) and toxicity equivalency factor (TEF) concepts because real-life exposures are to mixtures of PCDDs, PCDFs, PCDEs, and PCBs rather than to 2,3,7,8-TCDD alone. \u0000 \u0000 \u0000Keywords: \u0000 \u00002,3,7,8-Tetrachlorodibenzo-p-dioxin; \u0000accidents; \u0000Agent Orange; \u0000body burden; \u0000Cachexia; \u0000chloracne; \u0000chlorinated dibenzo-p-dioxins; \u0000dioxin; \u0000endocrine effects; \u0000IARC carcinogenic evaluation; \u0000tissues; \u0000US/foreign standards","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91383329","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":"Noncancer Risk Assessment: Principles and Practice in Environmental and Occupational Settings","authors":"L. Haber, Joan E. Strawson, A. Maier, Irene M. Baskerville-Abraham, A. Parker, M. Dourson","doi":"10.1002/0471435139.TOX005.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX005.PUB2","url":null,"abstract":"The approach to assessing the risks of noncancer toxicity has differed historically from that used to assess the potential risks of carcinogenicity. Assessment of risks of carcinogenicity has historically assumed that a small number of molecular events can evoke mutagenic changes in a single cell, ultimately leading to self-replicating damage and carcinogenicity. Generally, this is considered a nonthreshold effect because presumably all levels of exposure may pose a small, but finite, probability of generating a response. In contrast, it is most often assumed that noncarcinogenic changes have a threshold, a dose level below which a response is unlikely, because homeostatic, compensating, and adaptive mechanisms in the cell protect against toxic effects. \u0000 \u0000 \u0000 \u0000Modern understanding of mode of action (MOA), loosely defined as how a chemical causes the observed effect, has led to refinements in this dichotomy. Rather than considering cancer versus noncancer effects, the focus is on whether or not the chemical causes its effects by a mutagenic MOA, specifically DNA interaction. Nonthreshold approaches are generally used for effects resulting from interaction with DNA, while effects resulting from a nonmutagenic MOA (including both cancer and noncancer endpoints) are generally evaluated using threshold approaches. A recent NRC publication [1], however, recommended linear extrapolation under certain conditions for noncancer endpoints that do not involved interaction with DNA. The issues raised by that publication are addressed later in this chapter. \u0000 \u0000 \u0000 \u0000Recognizing both the historical approach and the importance of evaluation of MOA, this chapter will continue to use the term “noncancer risk,” but the methods described here should be understood to apply to both noncancer endpoints and cancer endpoints for which MOA information indicates that a threshold applies. This chapter describes the general framework for noncancer risk assessment and some salient principles for evaluating the quality of data and formulating judgments about the nature and magnitude of the hazard. Highlights of noncancer risk assessment methods used by a variety of agencies and organizations, and examples of how occupational risk assessment is moving toward a more systematic use of risk assessment principles are presented. \u0000 \u0000 \u0000 \u0000This chapter also has several specific aims. The first is to provide scientifically supportable quantitative risk assessment procedures to meet the risk assessment goals listed in the following paragraph. A second aim is to provide a scientific rationale that may be used to determine whether new quantitative risk assessment procedures not specifically examined in this chapter are scientifically supportable. The final aim of this chapter is to provide a basis for developing new or improved quantitative risk assessment procedures. \u0000 \u0000 \u0000 \u0000The quantitative risk assessment procedures described in this chapter have been developed to meet a variety of risk ass","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90978416","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":"Synthetic Polymers—Cellulosics, Other Polysaccharides, Polyamides, and Polyimides","authors":"F. Cavender","doi":"10.1002/0471435139.TOX091.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX091.PUB2","url":null,"abstract":"Natural polymers are biological macromolecules and are as old as life itself. Hemp, flax, cotton, and wood fibers from plants and silk and wool fibers from animals have been utilized since the dawn of civilization to make rope, paper, clothing, and furniture. What child has not been fascinated by a spider's web? The natural polymers include such diverse materials as proteins, polysaccharides, DNA, and polypeptides. The word polymer is derived from the Greek words poly, or many, and meros, or parts. This chapter will focus on cellulose and it derivatives, polyamides such as nylon and polyimides. \u0000 \u0000 \u0000 \u0000Cellulose plastics are produced by the chemical modification of cellulose. Raw cellulose is not a thermoplastic: it does not melt. Cellulose is a substance that forms the cell walls of many trees and other plants. Raw cellulose can be made into a fiber or film, but it must be chemically modified to produce a thermoplastic material. \u0000 \u0000 \u0000 \u0000Regenerating cellulose to yield the products rayon and cellophane removes the natural impurities. These regenerated products are essentially inert unless potential toxicants such as finishes and plasticizers are added in sufficient quantities to cause injury. Many cellulose derivatives would appear to be similarly inert. “Rayon” is, by definition, established by the Federal Trade Commission, the “generic name for a manufactured fiber composed of regenerated cellulose as well as manufactured fibers composed of regenerated cellulose in which substitutes have replaced not more than 15% of the hydrogens of the hydroxyl groups.” \u0000 \u0000 \u0000 \u0000Cellophane is “regenerated cellulose, chemically similar to rayon, made by mixing cellulose xanthate with a dilute sodium hydroxide solution to form a viscose, then extruding this viscose into an acid for regeneration. The term rayon is used when the material is in fibrous form.” Rayon is made from regenerated cellulose by forcing it through small holes into the coagulating acid bath at the end of the process, while cellophane is the film form of regenerated cellulose that has been forced through a thin slit into an acid bath. \u0000 \u0000 \u0000 \u0000All methods of preparation essentially depend upon solubilizing thin, short-fibered forms of natural cellulose, reshaping it into long fibers or film by extrusion through a spinneret or slit aperture, then immediately converting the extruded product back into solid cellulose. Rayon was first commercialized in the nineteenth century by the now discarded Chardonnet process that used highly flammable cellulose nitrate. The cuprammonium process replaced the Chardonnet process and is still used to a limited extent to produce extremely fine, silk-like filaments. Today the most widely used process is the xanthate or viscose process. \u0000 \u0000 \u0000 \u0000Generally, alkali cellulose is prepared by reacting wood pulp with excess sodium hydroxide (or other alkali), followed by aging to permit separation of the pulp fibers. The alkali cellulose is reacted with carbon disulfide to form","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89457905","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":"Synthetic Polymers—Olefin, Diene Elastomers, and Vinyl Halides","authors":"B. Walker, Lynette D. Stokes","doi":"10.1002/0471435139.TOX089.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX089.PUB2","url":null,"abstract":"Elastomers, also called rubber, can withstand considerably greater deformation than other materials and uniquely return essentially to their original shape even after substantial deformation. A familiar example is the behavior of a stretched rubber band after its release. All elastomers are composed of long macromolecular chains that assume a random coil conformation when undeformed. Deformation causes these coils to straighten out. Upon being allowed to relax, an elastomer returns essentially to its original shape because the chains reassume their random conformation. \u0000 \u0000 \u0000 \u0000The first elastomer identified, natural rubber, was described by Columbus as a ball that bounced. The first specialty elastomers, polysulfides and polychloroprene, were commercialized in the 1930s, natural rubber was the major industry product until World War II, when styrene-butadiene rubber (SBR) and acrylonitrile-butadiene rubber (NBR) were established as important synthetic rubbers. \u0000 \u0000 \u0000 \u0000From these early beginnings, the elastomer industry grew rapidly to a global elastomer demand of 15 million metric tons in 1990. The range and diversity of synthetic rubber becomes evident upon reviewing the Synthetic Rubber Manual that describes both thermosetting elastomers (TSE) and thermoplastic elastomers (TPE). \u0000 \u0000 \u0000 \u0000TSE and TPE exhibit important similarities. The most useful properties are the result of their long molecular chains linking to one another to form a three-dimensional network. In TSE this network is linked together with essentially irreversible cross-links. Vulcanization is the process of forming these cross-links, most typically using sulfur as the cross-linking agent. \u0000 \u0000 \u0000 \u0000TSE generally arrives at the rubber fabricators in bales. Ten or more ingredients might be added to the bale in heavy mixers before the compounded elastomer is shaped into a product and vulcanized. Schunk has characterized the health hazards of many of these ingredients, including carbon blacks, mineral fillers, plasticizers, protective and cross-linking agents, and accelerators. Broadly considered, these health hazards can be considered in terms of the following: \u0000 \u0000 \u0000 \u0000monomers, solvents, and other materials used to prepare elastomers \u0000 \u0000 \u0000 \u0000 \u0000storage and handling of elastomer (bales, pellets, and powder) \u0000 \u0000 \u0000 \u0000 \u0000processing of elastomers, generally at high temperatures \u0000 \u0000 \u0000 \u0000 \u0000finished rubber product \u0000 \u0000 \u0000 \u0000 \u0000 \u0000 \u0000Health hazards in processing, and storage and handling elastomers are the dominant focus of this section; limited references will be made to the other two areas where appropriate. \u0000 \u0000 \u0000 \u0000Certain portions of the material refer to monomer toxicology and epidemiology because some of the monomers used in manufacturing elastomers remain at low levels in the polymer. A full discussion of the toxicity of monomers is beyond the scope of this chapter. \u0000 \u0000 \u0000 \u0000Typical basic properties of certain elastomers are latter. Properties within a given class of elastomers can vary significantly. For","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85943087","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":"Monohydric Alcohols—C1 to C6","authors":"C. Bevan","doi":"10.1002/0471435139.TOX077.PUB2","DOIUrl":"https://doi.org/10.1002/0471435139.TOX077.PUB2","url":null,"abstract":"This chapter reviews both linear and branched monohydric aliphatic C1 to C6 alcohols. The C7 to C20 monohydric alcohols are covered in Chapter 78. \u0000 \u0000 \u0000 \u0000The low molecular weight alcohols, including methanol, ethanol, 1-propanol, and isopropanol are used extensively in industry (16). These alcohols exist as volatile liquids at ambient temperatures, and exposure can occur in both industrial and nonindustrial environments. \u0000 \u0000 \u0000 \u0000This review discusses primarily dermal and inhalation routes of exposure, which are the major routes of occupational exposure to alcohols. Many of the high-production alcohols such as methanol, ethanol, propanols, and butanols cause adverse effects when ingested; ingestion, however, is not a major route of occupational exposure. There are some alcohols that have produced adverse effects in humans, including death, in an occupational environment. Nevertheless, alcohols have been used extensively in the workplace generally with few or minor problems. Occasionally, methanol, ethanol, and the propanols produce a skin sensitizing response in humans. In some, but not all, cases the sensitization response was considered to be due to contaminants and not to the alcohol itself. \u0000 \u0000 \u0000 \u0000A common property of some of the alcohols is to produce local irritation to the skin, eyes, and respiratory tract, and the effect or potency varies for the type of alcohol. Many alcohols produce minimal or no adverse effects in humans, possibly because of low exposure combined with the low toxicity potential of the alcohol. \u0000 \u0000 \u0000 \u0000Few alcohols produce neuropathic effects in humans. Abuse of products containing methanol and ethanol has produced some indications of neurotoxicity in humans, but nothing has been reported in an occupational environment. 2-Hexanol produces neurotoxicity by the oral and intraperitoneal routes in animals, but there is no evidence of such an effect having occurred in the workplace. \u0000 \u0000 \u0000 \u0000There is no clear evidence that occupational exposures to alcohols represent a carcinogenic risk to humans. Based on epidemiological data, there is an association between the manufacture of ethanol and isopropanol by the strong acid process (a process no longer used in the United States) and an excess of upper respiratory tract cancer in humans. The effect has been attributed to by-products such as dialkyl sulfates and sulfuric acid, not the alcohols themselves. \u0000 \u0000 \u0000 \u0000Some of these alcohols such as ethanol and isopropanol can enhance the toxic effects of various chemicals, particularly hepatotoxins. It is thought that the effects may be due largely to an inductive effect of the alcohol on microsomal enzymes, particularly the cytochrome P450 system, which may allow a greater metabolic conversion of the hepatotoxin to its toxic metabolite. \u0000 \u0000 \u0000Keywords: \u0000 \u0000Methanol; \u0000Inhalation studies; \u0000Ethanol; \u00001-Propanol; \u0000Isopropanol; \u0000Butanols; \u0000Amyl alcohols; \u0000Hexanols","PeriodicalId":19820,"journal":{"name":"Patty's Toxicology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86313713","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}