Hydrocarbon, chlorinate, exposure

Polysulfones are handicapped by light and UV sensitivity requiring an efficient protection for outdoor exposure sensitivity to environmental stress cracking and attacks by chemicals such as aromatic hydrocarbons, chlorinated solvents and ketones the cost (justified by the performances) sometimes an insufficient fire resistance, but special grades are marketed. 

Sensitivity to light, requiring protection for outdoor exposure flammability except special grades attacked by aromatic hydrocarbons, chlorinated solvents, ketones cost. 

Rats did not survive when exposed for longer than 12-18 minutes to 12,000ppm. When exposed repeatedly to 470 ppm, they showed liver and kidney injury. Cardiac arrhythmias owing to sensitization of the myocardium to epinephrine have been observed with certain other chlorinated hydrocarbons, but exposure of dogs to perchloroeth-... 

Ethers are prominent members of a class of organic substances widely used as solvents, including hydrocarbons, chlorinated hydrocarbons, and alcohols, as well as ethers. Because of the widespread use of such solvents, human exposure is particularly likely. 

Kalliokoski P, Kauppinen T. 1990. Complex chlorinated hydrocarbons Occupational exposure in the sawmill. IARC Sci Publ 104 390-396. 

P. KalUokoski and T. Kauppinen, Complex chlorinated hydrocarbons occupational exposure in the sawmill industry, in Complex Mixtures and Cancer Risk, (Eds. H. Vainio, M. Sorsa and A. L. McMichael), lARC Scientific Pubhcation, Lion, N 104, 390, 1990. 

Polystyrene. Polystyrene [9003-53-6] is a thermoplastic prepared by the polymerization of styrene, primarily the suspension or bulk processes. Polystyrene is a linear polymer that is atactic, amorphous, inert to acids and alkahes, but attacked by aromatic solvents and chlorinated hydrocarbons such as dry cleaning fluids. It is clear but yellows and crazes on outdoor exposure when attacked by uv light. It is britde and does not accept plasticizers, though mbber can be compounded with it to raise the impact strength, ie, high impact polystyrene (HIPS). Its principal use in building products is as a foamed plastic (see Eoamed plastics). The foams are used for interior trim, door and window frames, cabinetry, and, in the low density expanded form, for insulation (see Styrene plastics). 

Hexachloroethane is considered to be one of the more toxic chlorinated hydrocarbons. The 1991 ACGIH recommended time-weighted average (TWA) for hexachloroethane was 1 ppm or 10 mg /m of air. Skin adsorption is a route of possible exposure ha2ard. The primary effect of hexachloroethane is depression of the central nervous system (147). Pentachloroethane and tetrachloroethylene are primary metaboHtes of hexachloroethane in sheep (148). 

The resistance to heat and aging of optimized EPM/EPDM vulcanizates is better than that of SBR and NR. Peroxide-cured EPM can, for instance, be exposed for 1000 h at 150°C without significant hardening. Particularly noteworthy is the ozone resistance of EPM/EPDM vulcanizates. Even after exposure for many months to ozone-rich air of 100 pphm, the vulcanizates will not be seriously harmed. EPM/EPDM vulcanizates have an excellent resistance to chemicals, such as dilute acids, alkaUes, alcohol, etc. This is in contrast to the resistance to aUphatic, aromatic, or chlorinated hydrocarbons. EPM/EPDM vulcanizates swell considerably in these nonpolar media. 

Polyamide or polyimide polymers are resistant to aliphatic, aromatic, and chlorinated or fluorinated hydrocarbons as well as to many acidic and basic systems but are degraded by high-temperature caustic exposures. 

This has a very high resistance to impact damage, even at subzero temperatures. It has good creep strength in dry conditions up to 115°C but degrades by continuous exposures to water hotter than 65°C. It is resistant to aqueous solutions of acids, aliphatic hydrocarbons, paraffins, alcohols (except methanol), animal and vegetable fats and oils, but is attacked by alkalis, ammonia, aromatic and chlorinated hydrocarbons. 

Liver cancer can also be a consequence of exposure to hepatotoxic chemicals. Natural hepatocarcinogens include fungal aflatoxins. Synthetic hepato-carcinogens include nitrosoamines, certain chlorinated hydrocarbons, polychlorinated biphenyls (PCBs), chloroform, carbon tetrachloride, dimethyl-benzanthracene, and vinyl chloride.Table 5.15 lists the chemical compounds that induce liver cancer or cirrhosis in experimental animals or... 

Dermal Effects. Some of the people in Woburn, Massachusetts, who had been chronically exposed to trace amounts of trichloroethylene and other substances in the drinking water reported skin lesions (Byers et al. 1988). These were maculopapular rashes that were said to occur approximately twice yearly and lasted 2-4 weeks. These skin conditions generally ceased 1-2 years after cessation of exposure to contaminated water. The limitations of this study are discussed in Section 2.2.2.8. A case study was published of a 63-year-old rural South Carolina woman exposed to trichloroethylene and other chlorinated hydrocarbons in her well water, who developed diffuse fascitis, although her husband did not (Waller et al. 1994). The level of trichloroethylene measured in the well water was 19 mg/L. Substitution of bottled water for drinking resulted in improved symptoms. 

The use of the methods for monitoring metabolites of trichloroethylene in blood and urine is, however, rather limited since the levels of TCA in urine have been found to vary widely, even among individuals with equal exposure (Vesterberg and Astrand 1976). Moreover, exposure to other chlorinated hydrocarbons such as tetrachloroethane, tetrachloroethylene, and 1,1,1-trichloroethane would also be reflected in an increase in urinary excretion of TCA. In addition, there may be sex differences regarding the excretion of trichloroethylene metabolites in urine since one experiment shows that men secrete more trichloroethanol than women (Inoue et al. 1989). The use of the level of trichloroethylene adduction to blood proteins as a quantitative measure of exposure is also possible, although obtaining accurate results may be complicated by the fact that several metabolites of trichloroethylene may also form adducts (Stevens et al. 1992). 

Geigy s mothproofing agent was a stomach poison for moths and other keratin-eating insects. It had a strong affinity for woolens, was harmless to warm-blooded animals and people, and had no offensive odor. As a chlorinated hydrocarbon, it was extremely persistent despite exposure to light and moisture. 

On the other hand, there is no evidence to support the assertion that polyethylene vapor berries deteriorate with exposure to soil chemicals. Construction film is a low-density polyethylene. High-density polyethylenes are used for the storage and transportation of an array of chemicals. Polyethylene is chemically stable, but may be adversely affected by aliphatic hydrocarbons (such as hexane, octane, and butane) and chlorinated solvents. It does not appear to be reactive with the acids and salts likely to be encountered in soil and concrete. 

The analysis methods are national in scope and address emissions from a wide variety of industrial and community source types. The materials reviewed are of widely disparate natures. They include metals, and bulk and trace hydrocarbons, including chlorinated and oxide derivatives of hydrocarbons. The analyses are intended to be preliminary screening analyses for use in scoping and prioritizing regulatory attention to toxic exposures from the chemicals studied. 

Both hexachloroethane and its lipophilic metabolites can distribute to body fat. Only hexachloroethane can be used to confirm compound exposure by way of a fat biopsy, since some of its metabolites are also produced from other chlorinated hydrocarbons or are present as contaminants in the environment. Based on one worker occupationally exposed to hexachloroethane, Selden et al. (1993) estimated that the plasma half-life in humans was several days, but less than one week. A clearance half-life in rats of 2.5 days was reported for hexachloroethane absorbed from the diet (Gorzinski et al. 1985). Therefore, similar to measurement of hexachloroethane in blood, urine, and feces, hexachloroethane in body fat is representative of current exposures rather than exposures that occurred weeks or months before testing. 

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