Chronic exposure to solvents

While the psychiatric effects of high-dose exposure to solvents remain unquestioned, the most recent reviews of the effects of low-level, chronic exposures to solvents reflect an ongoing debate (Filley and Kleinschmidt-Demasters 2001 Gamble 2000 Ritchie et al. 2001). The majority of recently performed controlled studies support a deleterious effect of low-level exposures (Condray et al. 2000 LoSasso et al. 2001 Morrow et al. 2001 Nasterlack et al. 1999). Other studies attribute subjective complaints in workers exposed to low-... 

At one time, benzene was widely used as a solvent, both commercially and in research and teaching laboratories. Its use for that purpose has largely been abandoned because of its toxicity. Chronic exposure to benzene vapor leads to various blood disorders and, in extreme cases,... 

Respiratory Effects. One study suggested increased respiratory disorders (asthma, bronchitis, pneumonia) in children with chronic exposure to a solvent-contaminated water supply (Byers et al. 1988). Two municipal wells in eastern Woburn, Massachusetts, were found to contain several solvents including trichloroethylene (267 ppb) and tetrachloroethylene (21 ppb). The increased susceptibility to infection may be secondary to effects on the immune system. Accurate chemical-specific exposure levels for individuals could not be determined because the water distribution system was designed to use water from different wells at different rates and times. Other limitations of this study are described in Section 2.2.2.8. 

Environment and health-related problems are especially determined by health risks due to solvents, which result in damage to skin and the central nervons system (polyneuropathy, encephalopathy) in the case of chronic exposure. Some solvents are also classified as being carcinogenic (e.g. benzene, trichloroethylene) or are suspected of being carcinogenic (e.g. perchloroethylene) or reproduction-toxic (e.g. toluene). 

Sohnlein B, Letzel S, Weltle D, et al Occupational chronic exposure to organic solvents XIV. Examinations concerning the evaluation limit value for 2-ethoxyethanol and 2-ethoxyethyl acetate and the genotoxic effects of these glycol ethers. Int Arch Occup Environ Health 64 479-484, 1993... 

Chronic exposure to commercial hexane solvent (51 % w-hexane) at concentrations up to 9000ppm was not carcinogenic to F-344 rats or to male B6C3F1 mice but did result in an increased incidence of liver tumors in female mice. It is unclear what components of the hexane mixture caused the neoplasms. ... 

Before 1940, most reports on the possible chronic toxicity of xylene also involved exposure to solvents that also contained high percentages of benzene or toluene as well as other compounds. Consequently, the effects attributed to xylene in these reports are questionable. Blood dyscrasias, such as those reportedly caused by benzene exposure, have not been associated with the xylenes. ... 

The terms acute and chronic are also used to characterize the time delay between exposure and the onset of symptoms. Acute effects are those noticed directly following exposure and are usually easily related to the agent. The chronic or long-term effects of an agent may occur years later and are often very difficult to attribute to a particular cause. The acute effects of alcohol consumption or exposure to the solvent in glue are obvious in the drunkenness produced. The effects of chronic exposure to these compounds, as seen by an alcoholic, are very different specifically, cirrhosis of the liver. The chronic effect of childhood lead exposure... 

Angerer J, Wulf H. 1985. Occupational chronic exposure to organic solvents. XI. Alkylbenzene exposure of varnish workers Effects on hematopoietic system. Int Arch Occup Environ Health 56 307- 321. 

Benzene, a component of motor fuel that is also widely used as an industrial solvent and as a starting material in organic synthesis, is a hematopoietic toxin. Chronic exposure to benzene vapors leads to pancytopenia, that is, decreased production of all types of blood cells (erythrocytes, leukocytes, and platelets). The long-term effect of benzene exposure is acute leukemia. 

Sandyk, R. Gillman, M.A. (1984) Motor dysfunction following chronic exposure to a fluoro-alkane solvent containing nitromethane. Eur. Neurol, 23, 479 81 Seizinger, D.E. Dimitriades, B. (1972) Oxygenates in exhaust from simple hydrocarbon fuels. J. Air Poll. Control Assoc., 22, 47-51... 

Skin irritation is a common problem with chronic exposure to liquid aliphatic hydrocarbons used as industrial solvents. These chemicals extract fats from the... 

Ruiz MA, Augusto LGS, Vassallo J, et al. 1994. Bone marrow morphology in patients with neutropenia due to chronic exposure to organic solvents (benzene) early lesions. Path Res Pract 190 151-154. 

Apart from the effects of acute exposure, lower level, chronic exposure can also have toxic effects. For example, it is argued that solvent disease includes impairment of memory and coordination, and changes in personality, but this is a contentious issue. Effects on organs hke the liver and kidney certainly do result from both acute and chronic exposure to certain solvents, for example carbon tetrachloride, which was used in dry cleaning but has now been replaced. 

Apart from the acute toxic effects of high concentrations of the more volatile solvents, there are health hazards from the long-term (chronic) exposure to low levels of solvents. Reproductive effects that are associated with chronic exposure to some solvents used in laboratories are shown in Table 11.8. Evidence from animal studies suggests there are reproductive hazards from handling other solvents. Eor example ... 

Several decades ago benzene was thought to be a harmless chemical with a somewhat pleasant odor and was widely used as a cleaning solvent. It has since been found that chronic exposure to... 

Fiedler, N., WelsefC., Lynch, R., Kelly-McNeil, K.,Wedeen, R., Jones, K., Udasin, L, Ohman-Strickland, P.,and Gochfeld, M.Cognitive effects of chronic exposure to lead and solvents. Am. J. Indust. Med. 2003 4 413-423. 

Krusell L, Nielsen HK, Baelum J, Lundqvist G, Omiand O, Vaeth M, Husted SE, Mogensen CE, Geday E. Renal effects of chronic exposure to organic solvents a clinically controlled trial. Acta Med Scand 1985 218 323-327. 

Porro A, Lomonte C, Coratelli P, Passavanti G, Maria Ferri G, Assennato G. Chronic glomerulonephritis and exposure to solvents a case referent study. Brit J Ind Med 1992 49 738-742. 

Paints often contain solvents such as toluene, xylene, halogenated aromatic hydrocarbons, and methylene chloride, as well as heavy metals in their pigments including chromium yellow, lemon yellow (barium chromate), vermilion red (cadmium and mercuric sulfides), and flake white (lead). Both acute and chronic exposures to toluene and xylene are associated with neurotoxicity and can also damage the liver and kidneys. 

Most of the current toxicological information suggests that heptane is, physiologically speaking, more neurotoxic than other aliphatic hydrocarbons such as pentane, hexane, and octane. However, debilitating peripheral neuropathy, such as that seen on chronic exposure to -hexane, has not been observed in animals or humans. Some cases of polyneuritis, observed in the absence of hexane exposure, might be attributed to the presence of heptane in a solvent mixture. No one to date has discerned a true toxic mechanism for heptane. 

Bleecker ML, Bolla KI, Agnew J, et al Dose-related subclinical neurobehavioral effects of chronic exposure to low levels of organic solvents. Am J Ind Med 19 715-728, 1991... 

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