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PubMed1987

[A chromatographic method of analysis of mixtures of methylethyl ketone, n-butyl alcohol, xylene, ethylene glycol, ethylene glycol acetate, cyclohexanol, cyclohexanone and butyl glycol vapors in the air].

A gas chromatographic method for the determination of the mixture of organic solvents in air has been developed. The optimum conditions of the separation of the mixture were obtained in the column packed with 10% UCON HB 2000 coated on Chromosorb W AW DMCS 80-100 mesh. The components of the mixture are collected on activated charcoal and desorbed with CS2. A quantitative analysis is made using methyl isobutyl ketone as an internal standard. The lowest detectable limit under proposed air sampling and analysis conditions is 0.1 TLV (threshold limit value) for each component of the mixture.

Air Pollutants, Occupational↗

PubMed1987

The urinary concentration of solvents as a biological indicator of exposure: proposal for the biological equivalent exposure limit for nine solvents.

Organic solvents are generally volatile substances that are absorbed mainly through the lungs; they are eliminated chiefly through the lungs and kidneys. In urine they are present as metabolites and, in very little part, as parent compound. The urinary concentration of solvent (Cu) can be used for the biological monitoring of exposed subjects to evaluate their exposure and correlate with the Threshold Limit Value (TLV) during the working day. The authors report some results obtained with workers occupationally exposed to solvents. The results concern the correlation between urinary concentration (Cu, micrograms/L) vs. average environmental concentration (Ci, mg/m3) measured in the breathing zone. For each solvent studied (acetone, 2-cyclohexane, 1,2-dichloropropane, n-hexane, methyl ethyl ketone, perchloroethylene, styrene, toluene, 1,1,1-trichloroethane) the authors propose a Biological Equivalent Exposure Limit (BEEL) corresponding to the environmental TLV.

Air Pollutants, Occupational↗

PubMed1986

[Effect of long-term exposure to high manganese levels in the air of the work area on the content of various immunoproteins in the blood].

Fifty-four subjects chronically exposed to high manganese concentrations due to professional melting of iron-manganese alloys have been examined. The threshold limit value was exceeded 3 to 4-fold. The minimum length of employment in exposure was 5 years, whereas the average-17.7 years. Control groups were matched by age, length of employment and energy expense. Among the determined parameters, i.e. IgG, IgA, IgM concentrations in blood serum and C3 and C4 elements of the complement--only the IgM concentration was significantly lower, whereas the others were not significantly different from those in relevant control groups.

Adult↗

PubMed1986

Organic solvent-induced encephalopathy in industrial painters.

Although organic solvents are essential components of an industrial economy, they are not used without risk. The relationship between excessive exposure to organic solvents and subsequent development of chronic encephalopathy has been recognized for nearly 100 years. Fifteen industrial painters who underwent evaluation in an occupational health clinic for symptoms that they related to their work were found to have a high prevalence of neurasthenic symptoms, most frequently, memory loss and personality change. Although neurologic and screening laboratory examinations showed no consistent abnormalities, psychological tests documented poor short-term memory and an array of neuropsychologic deficits. Personality profiles revealed depression, anxiety, and preoccupation with somatic concerns. These findings agree well with previous reports of "chronic painter's syndrome." Heightened awareness among industrial physicians and prospective studies to evaluate existing threshold limit values and personal protective equipment requirements are indicated.

Adult↗

PubMed1985

[Evaluation of exposure of workers to asbestos dust in asbestos-processing plants].

Working environments have been tested in plants producing asbestos products, asbestos-cement products, textile asbestos products, asbestos-caoutchouc plates, asbestos boards and asbestos frictional materials for automotive industry, Measurements of total dust concentrations and concentrations of asbestos fibres 5 micron long supported workers' exposure investigations. Basing on literature data on the working environment at the Mining Metallurgical Plant in Szklary, the health risk for workers producing nickel from ores containing asbestos mixtures has been analysed. The asbestos-exposure in asbestos-processing plants has been found to be still considerable despite modernization of the plants. Particularly dangerous to health have been regarded the conditions at asbestos spinning-mills and the Mining-Metallurgical Plant at Szklary, where even average asbestos concentrations considerably exceed the threshold limit values.

Air Pollutants, Occupational↗

PubMed1979

Air pollution analysis used in operating an environmental control unit.

A simple, fast and reliable method was developed to measure the origin and daily and seasonal variations of selected air pollutants in the Brookhaven Environmental Unit. None of the pollutants that were measured surpassed its threshold limit value. The average concentrations of the pollutants that were measured could be considered as preliminary standard for environmental units in hospitals as long as material analysis for outgassing is used simultaneously.

Air Pollutants↗

PubMed1979

Sources of parathion exposures for Israeli aerial spray workers, 1977.

Exposure of Israeli agricultural spray pilots and ground crews to parathion was studied. Measurements were made with personal samplers contianing wet midget impingers; samples were analyzed by gas chromatography. Cockpit air exposure levels during 11-21-minute sampling periods for 12 flights ranged from nearly 0 to 430 microgram/m3. During sampling periods of 30 minutes to 4 hours the threshold limit value (TLV) of 100 microgram/m3 was exceeded in 2 of 19 instances. In seven measurements of ground crew exposures, TLV was not exceeded. Air washing with parathion resulted in airborne contamination of the ground level area at more than three times the TLV. Skin exposure data suggested that this route of exposure was significant for ground crew workers but not for pilots. Calculations based on the present data and standard absorption formula suggested that total daily intake for ground crew, but not for pilots, exceeded the Accepted Daily Intake (ADI) of 5 microgram/kg body weight. Sources of exposure and contamination for ground crew and pilots were identified. Recommended environmental control measures for parathion exposure should include cockpit air filtration, modification in flight patterns, paving landing areas, installation of hosing and drainage, NaOH neutralization point, and separate loading and unloading sites. Personal control measures were suggested as a supplement.

Aerosols↗

PubMed1977

[Aspects of industrial hygiene in occupational exposure to the hazards of laser light].

The AA. outline the environmental hazards by the laser light taking into account the characteristics of this stimulated emission and the properties of the biological substrate to be damaged. They illustrate the optical and functional behaviour of the eye in order to demonstrate the peculiarities which make it the most important "critical organ" as regards the laser light. They furthermore propose some criteria for the analysis and the registration of the data necessary to individuate the hazards. They indicate the industrial hygiene measures to be adopted in the different exposure conditions and point out some aspects apt to individuate the levels for minimal reactive dose from which it is possible to define the threshold limit values. They conclude with the proposal to normalize as much as possible the rules of hygienistic protection in this new technological field.

Environmental Exposure↗

PubMedDate not supplied

Neurobehavioral testing of chemicals: impact on recommended standards.

Historically, the American Conference of Governmental Industrial Hygienists (ACGIH) has served as a major source of information on recommended safe exposure limits (Threshold Limit Values or TLV's) for chemicals most frequently encountered in U. S. industry and of known toxicologic significance. A review of the ACGIH Documentation book, which details the basis for their judgements, has indicated that 167 of the 588 chemicals for which they assigned recommended standards have, as one of their bases, direct nervous system effects. In order to increase the impact of future behavioral toxicology research on recommended standards, the neurotoxicologist can utilize certain strategies: (a) Focus on established mixtures in the environment of interest or select exposures of particular chemical classes, considering population size and severity of effect; (b) Ensure that the results of the study are referable to the expected route of exposure in the environment of interest; and (c) Select tests with face validity for non-psychologists, using reference substances. Finally, the neurotoxicologist is urged to consider effects related to safety as well as health in developing his/her research.

Air Pollutants, Occupational↗

PubMed1981

Neurobehavioral effects of toluene: a review.

Toluene appears to produce reversible effects upon liver, renal and nervous systems. Its usual route of intake is via respiration. The nervous system appears to be the most sensitive to the effects of toluene. Although there are few studies of toluene's neurotoxicity, some tenuous results can be cited. High level toluene exposures produced incoordination, ataxia, unconsciousness and eventually, death. Lower level acute exposures in man produce dizziness, exhilaration and confusion. Activity level has been inadequately studied. Schedule controlled behaviors have been reported to produce inverted U-shaped concentration-effect curves on response rate measures. Alterations at levels as low as 150 ppm have been reported when appetitive contingencies are used. Very few studies of the nervous system have been performed at levels below 1000 ppm and most of the results were inconclusive. The TLV (threshold limit value) of toluene has been set at 100 ppm for 8 hrs. No exposures on possible groups at special risk, such as perinatal, aged or impaired subjects have been made. Few studies of reversibility of effects in the nervous system have been reported. Much more work is needed before strong conclusions can be drawn.

Animals↗

PubMedDate not supplied

Neurotoxic effects in mercury-exposed workers.

Mercury levels in blood and urine and several nerve conduction velocities (CV) were measured in two groups of workers exposed to mercury (Hg) and in a reference group. Furthermore neuropsychiatric examination and psychological tests were performed. There was a significant mild degree of slowing of sensory CV, but no dose-effect relationship was evaluated on a group basis. The individual assessment showed in some cases hints of abnormal CV caused by mercury exposure. Significant correlations were found between duration of exposure and decrease of short-term memory. However there was no relationship in the case of the other psychological tests. In conclusion, results indicate that there are no disorders of central and/or peripheral nervous system function if the valid Biological Threshold Limit Values in FRG (50 micrograms Hg/l blood and/or 200 micrograms Hg/l urine) are not exceeded.

Adolescent↗

PubMed1978

Neurophysiological observations after chronic styrene exposure.

Thirty-three styrene exposed workers from three different industrial sites were examined with electroencephalography and motor and sensory neurography. The three groups had respective styrene exposures of clearly above the threshold limit value (50 ppm), at about this level, and clearly below it. The neurophysiological results were compared with those of a group of normal controls and a group of 17 patients judged to suffer from sequelae after long-term heavy exposure to organic solvents (mainly painters). Ten subjects in the styrene group presented signs of a mild sensory neuropathy with polyphasic sensory responses of a low amplitude. The same pattern was commonly found among the reference group heavily exposed to solvents. The ten subjects in the styrene group with mild polyneuropathy had a significantly higher age and significantly heavier styrene exposure than the rest of the group. Age difference could not explain the difference in the neurophysiological parameters, and therefore the contributing role of styrene exposure has to be considered. The electroencephalographic analysis showed no changes of the dominant alpha frequency. An increased amount of diffuse slow activity was seen in many of the heavily exposed mixed-solvent cases and was seen in some of the styrene-exposed cases without a clear relation to degree of exposure. An increased occurrence of fast activity in central and precentral areas of the brain was found in the styrene group, as well as in the mixed-solvent group. This pilot study indicates that the same type of neurophysiological changes from the strictly normal are seen among workers exposed to styrene as those found among a group of patients judged to suffer from sequelae after chronic exposure to various organic solvents. The neurophysiological "profile" is (a) sensory nerve responses with low amplitude and long duration, (b) somewhat low sensory conduction velocities, (c) close to normal motor neurographic findings, and (d) an increased amount of fast activity in central and precentral regions in the electroencephalogram in combination with normal occipital alpha activity.

Action Potentials↗

PubMed1995

Induction of nasal carboxylesterase in F344 rats following inhalation exposure to pyridine.

Carboxylesterases (CEs) in the nasal mucosa metabolize some inhaled esters, including industrially important acrylates and acetates, to toxic acid metabolites that produce site-specific lesions in the nasal epithelium. The metabolic capacity of CEs in the normal nasal mucosa is theoretically sufficient to protect the lower respiratory tract from toxicant-induced injury at concentrations of acrylates and acetates likely to be inhaled in industrial environments. Thus, alterations in the metabolism and toxicity of these substrates would be predicted with changes in the amount or activity of CE in the nasal mucosa. Although many other nasal enzymes have been reported to be relatively refractory to induction, the amount of CE in the nasal mucosa can be increased by inhalant exposure. In the liver, expression of CEs may be elevated in response to exposure to P450 inducers. To examine this phenomenon in the nose with the widely used industrial solvent pyridine, we examined the effect of pyridine inhalation at the threshold limit value concentration of 5 ppm, or at 444 ppm, 6 hr/day for 4 days on the localization and amount of immunoreactive CE in olfactory mucosas of F344/N rats. CE immunoreactivity was increased in Bowman's glands following exposure to 5 or 444 ppm pyridine, and in sustentacular cells most notably following the 5 ppm exposure. Quantitative densitometry showed a statistically significant, dose-related increase in the density of immunoreactive CE in Bowman's glands of pyridine-exposed rats. These results indicate pyridine, and possibly other solvents, can induce nasal CE, an enzyme not directly involved in the metabolism of those solvents, following low-dose, short-term exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

PubMedDate not supplied

The correct use of glutaraldehyde in the healthcare environment.

When using and handling glutaraldehyde-based instrument sterilants, it is important to employ appropriate industrial hygiene practices such as wearing the proper personal protective equipment and installing environmental controls. Every healthcare worker who uses glutaraldehyde, or any disinfectant, should be well trained and knowledgeable about the properties of the material(s), their potential harmful effects, and the cleaning/disinfecting procedures of the healthcare facility and infection control department. Appropriate gloves, gowns, and eye protection should be available and worn. If necessary, additional ventilation should be installed to keep glutaraldehyde vapor concentrations below the Threshold Limit Value (TLV), and respiratory protective equipment should be available for emergency situations. Finally, all employees should be aware of spill clean up procedures, which should include written instructions. By keeping employees well trained and informed and by utilizing good industrial hygiene practices, the chances of overexposure to glutaraldehyde-based instrument sterilants will be minimized, and working conditions will be comfortable and safe.

Environmental Monitoring↗

PubMed1994

Chronic neurobehavioural effects in paint formulators exposed to solvents and noise.

Twenty-one male paint formulators with an average age of 41.3 years (range 27-53), educational level of 7.4 years (range 5-10) and exposure level of 0.09 times Threshold Limit Value (TLV) index of solvent mixture (range 0.003-0.24 times TLV-index) for 20.2 years (range 7-39) were studied with a battery of neurobehavioural performance tests including digit span, digit symbol, Benton visual retention, finger tapping, grooved peg board, and aiming test. A group of 21 male workers matched for age (mean 40.8 years, range 25-53) and education (mean 6.9 years, range 5-12), and with no history of exposure to neurotoxic agents were selected as controls. In all the neurobehavioural tests, the exposed workers' performances were observed to be poorer than the controls'. Statistically significant differences were observed in digit span, grooved peg board, and the Z score after adjusting for age, level of education and ethnicity. The least square means for digit span were 11.7 (standard error [SE] 0.77) and 9.2 (SE 0.79); for grooved peg board were 60.5 (SE 2.1) and 69.7 (SE 2.1); and for neurobehavioural Z score were 0.02 (SE 0.11) and 0.50 (SE 0.11) in the controls and exposed workers respectively. The exposed group also performed significantly poorer in aiming test error score and digit span when compared to the controls after adjusted for age, education and ethnicity. The least square means for aiming test error score were 6.5 (SE 2.7) and 12.8 (SE 2.8) for the controls and exposed workers respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Reduction in operatory mercury levels after contamination or amalgam removal.

The threshold limit value (TLV) for occupational exposure to mercury can be exceeded in the dental operatory after a contamination event or during certain dental procedures. The objective of this study was to determine the time required for the mercury vapor levels to return to baseline in both non-ventilated and ventilated operatories after they had been contaminated with mercury to the TLV of 0.050 mg/m3; and to evaluate the efficiency of an activated charcoal filtering device for removing mercury vapor. The results showed that even in a poorly ventilated operatory, the mercury vapor level returned to background within 20-30 minutes after a contamination, and within 10-20 minutes when the operatory was ventilated. The filtering device reduced the level of mercury vapor by approximately 25% during a continuous contamination event, but did not clear the operatory faster than normal settling after a limited source contamination. The filter caused a significant reduction in mercury in the breathing zones of the patient and dentist during and after amalgam removal, but did not eliminate the exposure. This study demonstrated the difficulty in contaminating an operatory with mercury vapor and confirmed the limited time mercury remains airborne, presumably due to its density and affinity for surfaces.

Air Pollution, Indoor↗

PubMed1993

[Effects of low concentrations of NO2 on alveolar permeability and glutathione peroxidase in healthy subjects].

Potential toxic effects of prolonged NO2 exposure below the current threshold limit value (TLV) were examined in 14 healthy, non-smoking adults. The subjects were exposed to 2,3 ppm NO2 and to clean air for five hours with a one week interval between exposures. Physiological and biochemical measurements were obtained during exposure and the following 24 hours after. A 14% decrease in serum glutathione peroxidase activity (GSH-Px) was observed 24 hours after the start of the NO2 exposure while indications of a 22% decrease in alveolar permeability were found 11 hours after the start. There were no indications of mucous membrane irritation or of decreased lung function during or after NO2 exposures. The results support the assumption that a delayed response is a feature of the human reaction to NO2 even below the current TLV of three ppm, and they stress the importance of an extended period of observation in future NO2 exposure studies.

Adult↗

PubMed1993

[Interactions between organic solvents].

The purpose of this article is to review the knowledge at this time about interactions between organic solvents. The literature from the last 11 years (1980-1991) was searched in order to find descriptions of interactive effects concerning those 15 solvents, which most frequently exceeded the threshold limit value according to a recent Danish report. Thirty publications dealing with 23 different combinations of the solvents two by two, and four publications on a single solvent's ability to induce cytochrome P-450 isozymes, were found. Synergistic effects were reported for 11 of the 23 investigated combinations. The interactions of the solvents styrene, n-hexane, xylene, dichloromethane and toluene are described. The conclusion drawn is that the rule of additivity should be used with caution when dealing with combined exposure for organic solvents in industry. Certain solvents should not be used together.

Air Pollutants, Occupational↗