Chronic effect of solvent

The acute and chronic effects of solvent sniffing have been thoroughly reviewed (4). Solvents can be sniffed... 

Williamson AM, Winder C A prospective cohort study of the chronic effects of solvent exposure. Environ Res 62 256-271,1993 Winchester RV, Madjar VM Solvent effects on workers in the paint, adhesive and printing industries. Ann Occup Hyg 30 307-317, 1986... 

In the last several decades, there have been several studies in experimental animals, case reports in humans, case studies in humans, and epidemiological studies in humans on the effects of solvents on the kidney, both acutely and chronically. The scope of diis chapter is the clinical chronic effects of solvents on the kidney (chronic nephrotoxicology). 

Dichloroethylene is toxic by inhalation and ingestion and can be absorbed by the skin. It has a TLV of 200 ppm (10). The odor does not provide adequate warning of dangerously high vapor concentrations. Thorough ventilation is essential whenever the solvent is used for both worker exposure and flammabihty concerns. Symptoms of exposure include narcosis, dizziness, and drowsiness. Currently no data are available on the chronic effects of exposure to low vapor concentrations over extended periods of time. 

Tolerance is characterized by reduced responsiveness to the initial effects of a drug after repeated exposure or reduced responsiveness to a related compound (i.e., cross-tolerance). Animal studies have not provided conclusive evidence of tolerance to the effects of the centrally active compounds in toluene or trichloroethane (Moser and Balster 1981 Moser et al. 1985). Observations in humans, on the other hand, have documented pronounced tolerance among subjects who chronically inhale substances with high concentrations of toluene (Glaser and Massengale 1962 Press and Done 1967) and butane (Evans and Raistrick 1987). Kono et al. (2001) showed that tolerance to the reinforcing effects of solvents is comparable to that conditioned by nicotine but less intense than that reported with alcohol or methamphetamine use. 

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... 

Some new work has been done here which shows the effects of solvents exposure. A new study illustrates a simple method of detoxification using heat chamber depuration (sauna), and raises awareness in the practice of medicine of the importance of taking an environmentally oriented historical approach. The connection between symptoms of chronic degenerative diseases and environmental and/or nutritional factors is missed in many cases due to lack of obtaining an environmentally oriented medical history. Taking such a history and dealing with the cause of illness using avoidance and/or appropriate therapy is preventive and cost-effective for both the patient and society (Krop, 1998). 

Toluene (methylbenzene) does not possess the myelotoxic properties of benzene, nor has it been associated with leukemia. It is, however, a central nervous system depressant and a skin and eye irritant. It is also fetotoxic. See Table 56-1 for the TLVs. Exposure to 800 ppm can lead to severe fatigue and ataxia 10,000 ppm can produce rapid loss of consciousness. Chronic effects of long-term toluene exposure are unclear because human studies indicating behavioral effects usually concern exposures to several solvents. In limited occupational studies, however, metabolic interactions and modification of toluene s effects have not been observed in workers also exposed to other solvents. Less refined grades of toluene contain benzene. 

Adult rats were exposed to different concentrations of n-hexane and lung tissue was then examined. The direct toxic effect to pneumocytes could be demonstrated as definite regressive alterations, such as fatty generation and change of lamellar bodies of type II pneumocytes as well as increased detachment of cells. After chronic inhalation of solvents, conspicuous aggregation of lamellar discharge material of type II pneumocytes can be seen and, probably as a result of an irritated fat metabolism, there were large lysosome-like bodies with densely packed lipid material in type I pneumocytes. 

Edling C, Ekberg K, Ahlborg G, et al Long term follow up of workers exposed to solvents. British Journal of Industrial Medicine 47 75-82,1990 Ekberg K, Barregard L, Hagberg S, et al Chronic and acute effects of solvents on central nervous system functions in floorlayers. British Journal of Industrial Medicine 43 101-106,1986... 

The conceptual problem related to THC activity had been raised by the late William Paton of Oxford, who had pointed out that the cannabinoids belong to the group of biologically active lipo-philes and that their effects should be compared with the chronic effects of anesthetics and solvents. 

While the most common exposure route of a solvent in a worker is by way of vapor inhalation other hazards include entry through the skin absorption, ingestion into the digestive tract, and entry into the eyes. The health hazard data in Section 5 of the chemical s MSDS will list the effects of overexposure to the chemical via the various routes of exposure. Any permanent damage to the eyes from the chemical will be noted as well as the probability of absorption of the chemical through the skin. The health hazard section will also note any acute or chronic effects of overexposure and the target organs affected by the overexposure. 

Neuropsychologic and psychosocial antecedents and chronic effects of prolonged use of solvent and metamphetamine. 

Other Chronic Effects. Those solvents which are able to dissolve fats may cause dermatitis if there is prolonged skin contact, and those who handle solvents frequently should bear this in mind. The potential carcinogenicity of solvents is a matter about which concern is sometimes expressed, as are their possible reproductive effects. There is some rather poor evidence from animal experiments which purports to show that trichloroethylene is carcinogenic, but this has never been confirmed so far as human exposure is concerned. Some solvents can be shown to have mutagenic properties in laboratory tests but, again, there is no evidence which would lead one to believe that any of the solvents in common use can cause cancer. 

In a cross-sectional study, exposure and effect are studied simultaneously. This approach contains an inherent problem because exposure must precede the effect. However, it can he used to investigate acute effects and also mild chronic effects (which do not force people to leave their jobs) if exposure has remained rather stable for a long time. When the prevalence of the effects studied are compared with the prevalence in other worker groups (controls or references) which correspond otherwise with the study group but are not exposed to the agent investigated, indicative evidence of possible causality may be obtained. For example, cross-sectional studies have been applied successfully to reveal the associations between mild neurotoxic effects and exposure to organic solvents. ... 

Himnan DJ Tolerance and reverse tolerance to toluene inhalation effects on open-field behavior. Pharmacol Biochem Behav 21 625-631, 1984 Hinman DJ Biphasic dose-response relationship for effects of toluene inhalation on locomotor activity. Pharmacol Biochem Behav 26 65-69, 1987 Hormes JT, Filley CM, Rosenberg NL Neurologic sequelae of chronic solvent vapor abuse. Neurology 36 698—702, 1986... 

Rapid dermal absorption of trichloroethylene is evident from a study in which peak blood and exhaled air concentrations occurred within 5 minutes after a human subject immersed one hand in a solution of unspecified trichloroethylene concentration for 30 minutes (Sato and Nakajima 1978). Studies on dermal absorption of trichloroethylene in humans, as well as animals, are complicated by the fact that exposure in these studies is usually by direct contact of the skin with the undiluted chemical. Trichloroethylene is a lipophilic solvent that defats the skin and disrupts the stratum comeum, thereby enhancing its own absorption. Thus, the rate of absorption probably increases in a nonlinear fashion with greater epidermal disruption. Although the extent of absorption through the skin may be relatively modest with normal industrial use (Sato and Nakajima 1978 Stewart and Dodd 1964), there is insufficient information to evaluate the effects of chronic, low-level exposure in hiunans, especially when multiple routes may be involved. 

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... 

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. ... 

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. 

Chronic effects arise from the cumulative dose of a chemical which has resulted frcm integrated exposures over months or years. The best examples of airborne chemicals which produce only chronic effects are the fibrogenic dusts. However, most systemic poisons also produce chronic effects although some produce acute effects as well if inhaled in sufficient quantities during short intervals. For example, many halogenated solvents damage the kidney or the liver after long-term inhalation of moderate air concentrations but produce anesthesia or narcosis... 

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