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At least 19 recordsLinked to original sources

Monitoring of occupational exposure to nitrous oxide.

The occupational exposure of operating room personnel to nitrous oxide was investigated by using multiple spot sampling, integrated personal sampling and end-tidal sampling in an operating room which had no ventilation system. The effect of passive scavenging on occupational exposure was determined. The study showed that all three methods to determine occupational exposure can yield representative time-weighted exposure patterns. However, the integrated personal sampling was considered the preferable method as it involved considerable saving of time and labour compared with taking and analyzing multiple end-tidal and spot samples. Passive scavenging of waste anaesthetic gases led to a three-fold to six-fold reduction of exposure of operating room personnel to nitrous oxide.

Air Pollutants

Adjusting occupational exposure limits for moonlighting, overtime, and environmental exposures.

A mathematical model is used to predict relative body burdens of inhaled contaminants in workers who work two jobs or overtime, or who experience off-the-job exposure to air contaminants. Expected "peak" or maximum body burdens from multiple exposures are compared to those expected from the "normal" occupational exposure on which TLVs and Permissible Exposure Limits (PELs) arebased (five 8-hour days per week with zero off-the-job exposure). The model is designed to predict what adjustments to the TLVs and PELs are necessary to avoid accumulation of excess peak body burdens of contaminants from the additional exposures incurred. The general application of models to determine occupational exposure limits is reviewed, and several models are compared.

Air Pollutants

Human blood samples as indicators of occupational exposure to persistent chlorinated hydrocarbons.

The value of using human blood as an indicator of occupational exposure to persistent organochlorine compounds is demonstrated. Blood samples from a total of 35 persons divided into three different groups, with and without exposure to chlorinated hydrocarbons in the work atmosphere, have been investigated by gas chromatography using electron capture detection. It is shown that the group of workers with an occupational exposure to pentachlorobenzene, hexachlorobenzene, heptachlorostyrene and octachlorostyrene had a higher level of these chlorinated hydrocarbons in their blood samples than did the other groups. On the average, the concentration of hexachlorobenzene is about 20 times higher in blood samples from the occupationally exposed workers than from the control group. The level of hexachlorobenzene in blood samples of the control groups is low compared to recent studies of blood samples from the general population in other industrialized countries. Furthermore, the average value obtained for the exposed workers is of the same magnitude as the general population in these industrialized countries.

Air Pollutants

Control of occupational exposure to nitrous oxide in the oral surgery office.

Occupational exposure to inhalation anesthetics can be substantially reduced by control measures that have been recently developed. The incentive for their use should be the suspected relationship between chronic exposure to trace concentrations of agents, such as nitrous oxide, and health hazards. Control measures include the use of a newly developed scavenging nasal mask, relatively gastight anesthetic equipment, and vented suction machine, supported by an air monitoring program. With these measures, the concentration of nitrous oxide inhaled by the oral surgeons studied was reduced 97%.

Air Pollutants, Occupational

Persistent photosensitivity following occupational exposure to epoxy resin.

Persistent photosensitivity developed in eight men following occupational exposure to hot epoxy resin fumes. The condition was limited to sites the resin contacted. Small doses of ultraviolet-A light (2 to 5 joules/sq cm) evoked abnormal reactions consisting of erythema, edema, and papules in the clinically involved skin. Positive photopatch tests to epoxy resin were observed in four subjects, and to 4, 4'-isopropylidenediphenol (Bisphenol A) in all. The photosensitivity is most probably due to photocontact allergy to 4,4'-isopropylidenediphenol or to a closely related chemical.

Adult

Urinary hippuric acid concentration after occupational exposure to toluene.

The results of industrial investigations have shown a correlation between the rate of hippuric acid excretion in a single urine sample collected after daily occupational exposure and the amount of toluene absorbed. The rate of hippuric acid excretion and the average concentration of toluene vapour during exposure time were also related. The quantitative range of the test has been limited to amounts exceeding 425 mg of toluene and concentrations exceeding 69 ppm of toluene in the air because of the physiological presence of hippuric acid in urine. The rate of hippuric acid excretion in urine depends on diuresis and is constant for urinary fractions with diuresis of 30 ml/h. The physiological excretion rate was 20 mg/h with a standard deviation +/- 4.3 mg/h, maximal physiological level 33 mg/h.

Diuresis

Control of occupational exposure to nitrous oxide in the dental operatory.

Methods were developed for controlling the dental team's occupational exposure to nitrous oxide. The most applicable and effective use of these methods included the use of properly maintained gas delivery equipment, a double-walled scavenging nosepiece and vented suction machine, and minimizing speech by the patients. These methods were evaluated by measuring concentrations of nitrous oxide present in the air inspired by dental personnel. Before their use, the dentist inhaled 900 ppm nitrous oxide; their application reduced his inhaled concentration to 31 ppm, representing a 97% reduction. These methods were well accepted during 157 procedures completed by a group of eight dentists engaged in private practice (four general practitioners, two pedodontists, and two oral surgeons).

Air Conditioning

Risks to the offspring from parental occupational exposures.

Risks to the offspring of workers with occupational chemical exosures may derive from mutagenic, teratogenic or carcinogenic effects of industrial agents to which the parents are exposed. Evidence for impaired pregnancies and hazards to the offspring of working populations with chemical exposures is, however, very limited. Perhaps the best documented example is increased spontaneous abortion rates in female operating room personnel who have first trimester exposure to waste anesthetic gases. Evidence is reviewed for hazards to the offspring resulting from parental occupational exposure to vinyl chloride, benzene, chloroprene, radiation and petroleum-derived hydrocarbons. It is essential in investigating the role of occupational factors that other environmental and behavioral factors with major effects on pregnancy outcome be accounted for. These include smoking, alcohol, and drug exposures. An approach to surveillance for chromosomal abnormalities in offspring of occupationally exposed parents is outlined.

Alcohol Drinking

Styrene use and occupational exposure in the plastics industry.

The commercial production of styrene was started in the 1930s. Currently 7 million tons of styrene a year is made worldwide by the catalytic dehydrogenation of ethylbenzene or by a process in which styrene is produced as a coproduct with propylene oxide. An estimated 62% of the styrene monomer is consumed in the manufacture of polystyrene, 12% in acrylonitrile-butadiene-styrene resins, 17% in styrene-butadiene rubber and latex, 7% in unsaturated polyester resins, and 2% in other applications. Occupational exposure to styrene occurs in monomer production and polymerization plants, during the fabrication of plastic products from monomeric or partly prepolymerized styrene, and during the transportation and handling of liquid styrene. Due to unreacted residual monomer or thermal degradation of the polymer, low concentrations of styrene can be detected during the use of plastic products. The most extensive and intensive exposure occurs in the reinforced plastics industry, in which over 200,000 workers are exposed to a styrene concentration typically ranging from 20 to 300 ppm.

Air Pollutants

Evaluation of occupational exposure to xylene by blood, exhaled air and urine analysis.

Occupational xylene exposure in the breathing zone of 15 painters was measured during three consecutive workdays. The applicability of the use of different biological samples was tested by the monitoring of xylene concentrations in blood and exhaled air, and urinary methylhippuric acid excretion as well. The best relation to the time-weighted average of xylene exposure was obtained for urinary methylhippuric acid concentration at the end of the workday; an amount of 665 mg/g of creatinine corresponded to 50 ppm of xylene. The amount of methylhippuric acid in a morning sample at the end of the work week, on the other hand, correlated to the mean exposure of the three preceding days. Xylene concentrations in exhaled air and blood sampled after the workday correlated poorly to the exposure of the preceding day. The urinary elimination of methylhippuric acid after the finished work week showed two distinct phases of excretion, with different biological half-times (1.9-5.3 h for the first 10 h after exposure and 16.5-48.4 h for the next two days).

Adult

Isotachophoretic analysis of mandelic acid, phenylglyoxylic acid, hippuric acid and methylhippuric acid in urine after occupational exposure to styrene, toluene and/or xylene.

A simple, rapid and sensitive analytical method has been developed for the determination of phenylglyoxylic acid, mandelic acid, hippuric acid and methylhippuric acid; 0-, m- and p-methylhippuric acids are partly separated. These compounds are found as metabolites after occupational exposure to styrene, toluene and xylene. The method has been applied successfully to samples extracted from human urine by diethyl ether. The method can be used to accurately and simultaneously determine as little as 0.5 nmole of all of these acids in less than 20 min.

Chromatography, Gas

[Biochemical and electrophysiological studies in subjects with occupational exposure to lead poisoning].

In 36 men working in occupations with lead exposure the conduction velocity was measured in the motor fibres of the median, ulnar and peroneal nerves, and determinations were carried out of blood lead level, 24-hour urinary excretion of lead and delta-aminolaevulinic acid, and activity of delta-aminolaevulinic acid dehydratase in the erythrocytes. The comparison of the results of electrophysiological and biochemical investigations shows that lesions of the peripheral nervous system are not always correlated with the biochemical indices of lead poisoning and that peripheral nervous system damage, mainly subclinical, may develop in early period of exposure.

Adult

Health hazard from occupational exposure to metallic copper and silver dust.

This review of the toxicity and occupational hazard from exposure to metallic copper and silver dust was undertaken to examine the bases for the current standards and to suggest an alternative approach to controlling potential occupational hazard in conditions where exposures are limited to the prime metals. There are no data to suggest that exposure to silver or copper metal dust has produced remarkable disease in man. Further, there is no reason to consider the dust from either of these metals to be anything but nuisance particulate as defined by the ACGIH. They should, therefore, be regulated as such at the recommended level of 10 mg/m3.

Copper

Occupational exposure to 2,4-dichlorophenoxyacetic acid (2,4-D) and associated oxidative and genomic biomarkers among soybean farmers: a cross-sectional study.

BACKGROUND: 2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely used for weed control in soybean cultivation. This study aimed to investigate hepatic and genetic damage biomarkers in farmers occupationally exposed to 2,4-D, widely used in soybean cultivation in southern Brazil (Rio Grande do Sul), in addition to estimate urinary 2,4-D concentrations as an indicator of recent exposure. METHODS: A cross-sectional study was conducted, including 54 occupationally exposed farmers and 51 non-exposed controls (organic farmers). RESULTS: Urinary 2,4-D was detected in 88.5% of the exposed group versus 25% of the controls (p&#xa0;<&#xa0;0.001). Creatine kinase (CK) was significantly elevated in the exposed group (p&#xa0;<&#xa0;0.05), suggesting possible muscle injury, while AST and ALT (classical liver enzymes) did not differ between groups. Oxidative stress markers showed a clear pattern of redox imbalance, with increased TBARS (p&#xa0;<&#xa0;0.001), increased CAT activity (p&#xa0;<&#xa0;0.001), and reduced SOD activity (p&#xa0;<&#xa0;0.001). Telomere length was significantly shorter in the exposed group (p&#xa0;=&#xa0;0.001). Use of personal protective equipment (PPE) was reported to be inadequate. CONCLUSION: Occupational exposure to 2,4-D is associated with systemic oxidative stress and telomere shortening, even in the absence of transaminase elevation. This points to early hepatocellular vulnerability mediated by oxidative mechanisms rather than overt cytolysis. The study emphasizes the need for continuous monitoring of populations chronically exposed to chlorophenoxy herbicides.

2,4-dichlorophenoxyacetic acid

Asthma due to non-occupational exposure to toluene (tolylene) di-isocyanate.

The production of asthma by toluene di-isocyanate, aspirated into the ventilating system and emanating from the exhausts of a neighbouring factory, was established in three otherwise non-exposed clerical workers. Occupational-type exposure tests with a polyurethane varnish/toluene di-isocyanate mixture elicited vigorous and prolonged non-immediate asthmatic reactions, thus enabling identification of the otherwise, obscure etiological cause of their asthma.

Adult