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PubMed2004

Male exposure mediated adverse reproductive outcomes in carbon disulphide exposed rayon workers.

The authors examined 100 carbon disulphide (CS2) exposed male workers who had been employed ten years prior to study were selected for the study. They were virtually obliged to participate in the study by the Medical Labor Inspector and all of them participated voluntary. The aim was to assess the effects of occupational exposure to carbon disulphide concentrations below the threshold limit value (31 mg/m3) on the reproductive functions with special emphasis on miscarriages. Specially, workers history records were build up on number of children, miscarriages and general weakness, mental fatigue etc. It was found that the incidences of number of miscarriages against number of living children correlated well with environmental concentration of CS2. Where the average CS2 levels were 1.695 ppm, the incidences of miscarriages was 5.71% (group 1). Where as in group 2 environmental concentrations were 12.28 ppm and the incidences of miscarriages were 18.91%. It was also found that in the spinning department the exposure exceeds many times the Threshold Limit Values (TL V).

Abortion, Spontaneous↗
PubMed1997

Blue-yellow deficiency in workers exposed to low concentrations of organic solvents.

OBJECTIVES: To evaluate the effects of low concentrations of organic solvents on color vision. METHODS: Color vision was examined in 24 workers exposed to mixtures of solvents and in 24 control subjects. Exposure to mixtures was below the threshold-limit values. Color vision ability was assessed using the Ishihara plates (to screen for congenital dyschromatopsia), the Farnsworth panel D-15 test, the Lanthony desaturated panel D-15 test, and the Standard Pseudoisochromatic Plates part 2 (SPP2 test). RESULTS: The comparatively less sensitive Farnsworth panel D-15 test failed to show any difference between the groups, but the Lanthony panel D-15 desaturated test as well as the SPP2 test showed a significant impairment in the exposed group. Errors were of the blue-yellow type. CONCLUSION: This study gives further evidence that even mixtures of organic solvents at concentrations below the threshold-limit values may impair color vision.

Adult↗
PubMed1993

[Toluene diisocyanate-induced bronchial hyperreactivity in an animal model of occupationally-induced lung diseases].

UNLABELLED: Diisocyanates, widely used in industry for the production of polyurethanes, paints and adhesives represent a growing problem in occupational medicine. Beside toxic responses, isocyanates induce sensitization of exposed workers and may cause asthmatic reactions. To study the pathomechanisms of acute isocyanate induced lung injury, we developed an animal model using anaesthetised rabbits. Inhalation of toluene diisocyanate (TDI) in the range of threshold limit value (TLV) of 10 ppb (as well as 5 and 30 ppb) four times for a period of one hour, performed in 3 groups of 8 rabbits, did not significantly alter airway resistance (R), dynamic elastance (Edyn), slope of inspiratory pressure generation (dPoes/TI), arterial pressure (Pa) or arterial blood-gas tensions (PaO2, Pa-CO2) within time of exposure. In these experiments, before and after each TDI inhalation, unspecific airway responsiveness to 2% Acetylcholine (ACH) aerosol, inhaled for 1 minute, was measured. After 4 hours of TDI-inhalation, the amplitude of the bronchoconstrictory responses to ACH rose significantly (p < 0.005) to 3.6 times of the control value. Similar changes in the amplitude of airway resistance were measured. After inhalation of 5 ppb TDI no significant changes in airway reactivity were noticed, whereas the responses were further enhanced with 30 ppb TDI. In a control group of 8 animals, not undergoing TDI inhalation, the responses of Edyn, R and delta Pöes/TI to ACH aerosol inhalation did not significantly alter from one challenge to another. CONCLUSION: Diisocyanate atmospheres of threshold limit value of 10 ppb cause bronchial hyperreactivity within 4 hours of exposure in our rabbit model of occupational lung disease.

Animals↗
PubMed1987

Evaluation of the nephrotoxic potential of styrene in man and in rat.

The urinary excretion of beta 2-microglobulin, retinol-binding protein and albumin was measured in 65 workers exposed to styrene at levels averaging 50 percent of the current threshold limit value (215 mg/m2) for 1-13 years (mean: 6 years). By comparison with a control group matched for age and socioeconomic status, no significant difference was observed in the urinary excretion of proteins. In rats, styrene was weakly nephrotoxic. No functional or morphological renal change could be disclosed in rats exposed to 565 mg of styrene/m3, 5 days/week for 13 weeks. The repeated i.p. injection of 1 g styrene/kg (1/5 of oral LD50) for 10 days induced only a slight tubular dysfunction as evidenced by a 5-fold increase in beta 2-microglobulinuria. Altogether, these epidemiological and experimental data suggest that the current threshold limit value for styrene (215 mg/m3) proposed by the American Conference of Governmental and Industrial Hygienists does not entail any risk of renal toxicity.

Adult↗
PubMed1982

Car painters' exposure to a mixture of organic solvents. Serum activities of liver enzymes.

The serum activities of liver enzymes of car painters (N = 102) exposed to a mixture of solvents [toluene, xylene, and other constituents; about half the threshold limit value recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) in 1981] were compared with those of age-matched referents (N = 102). The activities of aspartate aminotransferase, alanine aminotransferase, ornithine carbamoyl transferase, and gamma glutamyl transferase did not differ between the exposed and the nonexposed groups. Simultaneous neurophysiological and ophthalmological examinations of the same car painters had distinguished subgroups of "solvent-affected" and "non-affected" car painters. The enzyme activities were not higher in the "affected" subgroups than in the "nonaffected" ones. The results suggest that car painters' exposure to organic solvents (at the overall level of half the threshold limit value of the ACGIH) does not increase liver enzyme activities in routine tests.

Adult↗
PubMed2001

Effects of formaldehyde on the frog's mucociliary epithelium as a surrogate to evaluate air pollution effects on the respiratory epithelium.

The increasing use of alcohol as an alternative fuel to gasoline or diesel can increase emission of formaldehyde, an organic gas that is irritant to the mucous membranes. The respiratory system is the major target of air pollutants and its major defense mechanism depends on the continuous activity of the cilia and the resulting constant transportation of mucous secretion. The present study was designed to evaluate the effects of formaldehyde on the ciliated epithelium through a relative large dose range around the threshold limit value adopted by the Brazilian legislation, namely 1.6 ppm (1.25 to 5 ppm). For this purpose, the isolated frog palate preparation was used as the target of toxic injury. Four groups of frog palates were exposed to diluted Ringer solution (control, N = 8) and formaldehyde diluted in Ringer solution at three different concentrations (1.25, 2.5 and 5.0 ppm, N = 10 for each group). Mucociliary clearance and ciliary beat frequency decreased significantly in contact with formaldehyde at the concentrations of 2.5 and 5.0 ppm after 60 min of exposure (P<0.05). We conclude that relatively low concentrations of formaldehyde, which is even below the Brazilian threshold limit value, are sufficient to cause short-term mucociliary impairment.

Air Pollutants↗
PubMed1992

Survey of cobalt exposure and respiratory health in diamond polishers.

This cross-sectional study was undertaken after the discovery of cobalt-related fibrosing alveolitis and bronchial asthma in diamond polishers occupationally exposed to cobalt. A total of 194 workers from 10 diamond polishing workshops and 59 workers from three other workshops from the diamond industry (control subjects) were studied; a questionnaire was administered and spirometry was performed. Cobalt exposure was assessed by environmental air sampling using both area and personal sampling and by measuring urinary cobalt concentration. When considered on a workshop basis, these environmental and biologic indices of exposure correlated well with each other. These measurements led to the definition of three cobalt exposure categories: a no exposure group, a low exposure group, and a high exposure group. The high exposure was, however, still below the present threshold limit value for cobalt (50 micrograms/m3). Spirometry showed that indices of ventilatory function (FVC and FEV1) were significantly (p less than 0.05) lower in the group with the highest exposure to cobalt. These differences were not due to differences in smoking habits. The results were confirmed when the data were analyzed by covariance analysis of lung function indices against smoking status, taking mean cobalt exposure in each workshop as a covariate, and when the data were analyzed by multiple regression analysis. This analysis showed that cobalt exposure correlated with decreased pulmonary function. Our results suggest that, during diamond polishing, exposure to cobalt at levels below the current threshold limit value is associated, on a group basis, with measurable effects on lung function parameters. The relationship between these cross-sectional epidemiologic findings and the occurrence of overt lung disease in diamond polishers remains to be established.

Air Pollutants, Occupational↗
PubMed2004

[Occupational exposure to hand-transmitted vibration in Poland].

BACKGROUND: Occupational exposure to hand transmitted vibration may cause disorders in upper extremities known as hand-arm vibration syndrome. Therefore it is essential to know the sources of vibration, occupational groups exposed to vibration and the number of exposed workers. The aim of the study was to estimate the number of men and women exposed to hand-transmitted vibration in Poland. MATERIALS AND METHODS: The completed questionnaires were obtained from 265 (80%) sanitary inspection stations. They included questions on: the name of workplaces, the name and the type of vibration sources, workers' gender, the number of workers exposed to vibration, indicating the extent of exposure measured against the three threshold limit values (< 0.5 TLV; 0.5 < TLV < 1 and > 1 TLV), and the number of workers exposed to hand-transmitted vibration not documented by measurements in a particular workplaces, indicating one of the three possible kinds of exposure (occasional, periodical and constant). The questionnaire data were based on measurements and analyses performed in 1997-2000. RESULTS AND CONCLUSIONS: The results of the study showed that vibrating tools used by grinders, fitters, locksmiths, rammers, road workers, carpenters and smiths proved to be the most frequent sources of hand-transmitted vibration. It was revealed that 78.6% of operators of these tools were exposed to vibration exceeding 1 TLV. The study also indicated that 17,000 workers, including 1700 women, were exposed to vibration exceeding the threshold limit values.

Arm Injuries↗
PubMed1979

Individual mercury exposure of chloralkali workers and its relation to blood and urinary mercury levels.

On two occasions, chloralkali workers were investigated with regard to personal air mercury exposure, blood mercury and urinary mercury. The first investigation (13 workers, 2 weeks) was made at an exposure above the threshold limit value (64 microgram/m3, range 36--112), the second (16 workers, 8 weeks) at a lower exposure (23 microgram/m3, range 15--43). At the higher level of exposure, good correlations were found between air exposure and blood or urinary mercury for the group, but not for individuals. At the lower level, the correlations were less pronounced for the group. For individuals, the best correlation was found between mean air exposure during one week and blood mercury about half a week later. Other individuals, mainly the least exposed, showed no such correlation. Corresponding correlations were not found for urinary mercury. The urinary excretion rate was determined only for the last few hours of the workday, but the results agree with earlier investigations of 24-h excretion on a group basis. The threshold limit value for mercury in air (50 microgram/m3) corresponds to 150--175 nmol Hg/1 blood (= 30--35 microgram/1) for the group, with large individual variation.

Adult↗
PubMed1986

Respiratory effects of occupational exposure to tobacco dust.

Few investigations of the respiratory effects of occupational exposure to tobacco dust have been carried out and the threshold limit value has not well been established. A cross sectional survey on a sample of 223 male and female workers at a cigar and cigarette factory in Lucca (Tuscany) showed a significantly higher prevalence of wheezing, attacks of shortness of breath with wheezing, dyspnoea, and rhinitis than in a reference population. A trend towards a decrease in forced end expiratory flows according to smoking habit and work duration was evident. Positive skin prick tests were observed in 26% of men and 23% of women and were positively associated with duration of work and negatively with cigarette smoking. Thin interstitial space involvement was observed on chest x ray examination in almost half the female workers with more than 35 years exposure. These findings suggest that prolonged exposure to tobacco dust may have negative health effects and that it is advisable to establish a threshold limit value for tobacco dust different from that of inert dust.

Adult↗
PubMed1993

Enhanced hepatic expression of P450IIE1 following inhalation exposure to pyridine.

Previous research has shown that intraperitoneal injection of the solvent pyridine results in a dose- and time-dependent induction of hepatic P450IIE1 in rats, with a twofold increase observed at 6 hr post-treatment. However, inhalation is the primary route of exposure expected for humans exposed to pyridine in laboratory and industrial settings or in tobacco smoke. In view of the potency and rapidity of induction associated with pyridine treatment, research was initiated to examine whether inhalation of the solvent at the current threshold limit value level of 5 ppm or at an elevated level of 440 ppm resulted in sufficient nasal and pulmonary uptake and systemic redistribution to cause increased hepatic expression of rat cytochrome P450IIE1. Rats were exposed, 6 hr/day, to 5 ppm pyridine for 4 days; to 440 ppm pyridine for 1 or 4 days; or to filtered air for 1 or 4 days. Rats were sacrificed 18 hr after the last exposure. Liver samples were taken from the air- and pyridine-exposed rats. Expression of immunoreactive P450IIE1 was examined in tissue sections using immunohistochemistry and in microsomal preparations using Western blot analyses. Hepatic tissue obtained from rats exposed to 5 ppm pyridine for 4 days or to 440 ppm pyridine for 1 or 4 days displayed significantly elevated levels of immunoreactive P450IIE1. Immunohistochemical analyses of liver sections showed that inhalation of pyridine at 5 ppm resulted in an elevated expression of P450IIE1 in hepatocytes surrounding terminal hepatic venules (THVs). Exposure to 440 ppm pyridine caused both increased expression of IIE1 in hepatocytes surrounding THVs after a single 6-hr exposure and an approximately three- to fourfold increase in the total number of cells expressing IIE1 after 4 days of exposure. Dilution analysis of immunohistochemically stained tissue revealed a significant difference between air-exposed controls and pyridine-exposed rats, at all exposure levels. P450IIE1 levels in microsomes isolated from rats receiving 5 and 440 ppm pyridine for 4 days were increased 2.5- and 10-fold as judged from scanning laser densitometry. This study reveals that inhalation of pyridine vapors at levels equal to or greater than the current threshold limit value of 5 ppm results in significant hepatic induction of P450IIE1 in rats.

Administration, Inhalation↗
PubMed2000

The relationship between TLV-TWA compliance and TLV-STEL compliance.

The purpose of this study was to investigate the relationship between the American Conference of Governmental Industrial Hygienists' (ACGIH) time-weighted average (TLV-TWA) and short-term exposure limit (TLV-STEL) Threshold Limit Values (TLVs). It is of value to determine if one or the other of these exposure limits is inherently more stringent so that exposure monitoring strategies may be devised which efficiently use available resources and effectively control exposures to meet both exposure limits. The ACGIH short-term exposure limit (TLV-STEL) imposes three conditions on short-term (15-minute) exposures. These conditions involve exceeding the TLV-TWA and TLV-STEL levels and the time-separation of those short-term exposures that exceed the TLV-TWA level. These conditions were analyzed to produce eight unique component probabilities for TLV-STEL non-compliance. The sum of these eight components is the total probability of TLV-STEL non-compliance. Mathematical expressions for the eight probability components are derived in terms of the probability that a single 15-minute exposure exceeds the time-weighted average threshold limit value (TLV-TWA) and the geometric standard deviation of these 15-minute exposures. These expressions were applied to various hypothetical workplaces, and the relationship between TLV-TWA and TLV-STEL compliance is presented. The results showed that non-compliance of 15-minute exposures with the TLV-STEL level is only one part of overall TLV-STEL non-compliance. The additional ACGIH provisions for TLV-STEL compliance--the number of 15-minute exposures exceeding the TLV-TWA level and the number of clean periods separating such exposures--can be important factors in determining TLV-STEL compliance. It is concluded that compliance with all provisions of the ACGIH TLV-STEL adds a degree of stringency that greatly enhances the likelihood of TLV-TWA compliance for most workplace environments.

Beryllium↗
PubMed1997

[Exposure of the pediatric surgeon to inhalation-anesthetic during pediatric bronchoscopy procedures].

BACKGROUND: General anaesthetic agents are frequently used for paediatric bronchoscopy. A disadvantage of this open system anaesthesia seems to be the contamination of the working environment. The aim of this study was to determine the exposure of the endoscopist during paediatric bronchoscopy under general anaesthesia in different working environments and to compare these measurements with the currently valid international threshold limit values. MATERIAL AND METHODS: 25 children (ASA I-III) scheduled for diagnostic bronchoscopy were included in the study. After inhalational induction all children were intubated with a nonflexible bronchoscope and manually ventilated through a side arm of the bronchoscope. Maintenance of anaesthesia was achieved with sevoflurane (2-3 vol%) in 80% oxygen. Trace concentrations were measured every 90 seconds in the breathing zones of the paediatrician by means of a highly sensitive direct-reading instrument (Brüel & Kjaer 1302). The lower detection limit was 0.02 ppm. The investigation was done in an OT with and without air conditioning and scavening system. RESULTS: The mean age of the children was 50.3 months (range: 3-109 months). Ventilation and oxygenation were stable throughout the bronchoscopic procedure. Mean exposure of the paediatrician without air-conditioning and scavening system to sevoflurane was over 50 ppm for the endoscopist. All international threshold limit values were exceeded. Peak concentrations higher than 100 ppm sevoflurane were detected repeatedly in 40% of anaesthesias. During bronchoscopy in the operating room equipped with laminar air flow (20.2 air exchanges per hour) and narcotic gas evacuation (30 l/min) the mean exposure of the paediatrician was 26.4 ppm sevoflurane. CONCLUSIONS: The main finding of the present study is that under inhalation anaesthesia with sevoflurane for paediatric bronchoscopy occupation exposure is higher than the limits stated in all known health regulation guidelines. Therefore, in case of such working conditions, the use of total intravenous anaesthesia is advocated also in very small infants.

Adult↗
PubMed2003

Naphthalene--an environmental and occupational toxicant.

For many years naphthalene had been considered as a non-carcinogenic polycyclic aromatic hydrocarbon (PAH). Airborne naphthalene concentrations have always been observed to be below the limit values of various national committees, such as the threshold limit value (TLV) of the American Conference of Governmental Industrial Hygienists (ACGIH) and the MAK of the Deutsche Forschungsgemeinschaft (DFG) (10 ppm). Since 2000, when the US National Toxicology Program revealed clear evidence of the carcinogenic activity of naphthalene in rats, international agencies [the International Agency for Research on Cancer (IARC), the US Environmental Protection Agency (US EPA), DFG] have reclassified naphthalene as a potential human carcinogen, and the European Union (EU) is currently preparing a new risk assessment report. It is presently unknown how to protect humans from health risks resulting from occupational and environmental naphthalene exposure. Knowledge about the external and internal exposure of humans serves as the key determinant in a comprehensive risk assessment. We review here ambient monitoring studies concerning the external naphthalene exposure that results from ubiquitous environmental sources (indoor and outdoor air, water, soil, food) and from a variety of critical workplaces (coking plants, creosote impregnation, distillation of coal tar and naphthalene, manufacture of refractories, graphite electrodes, aluminium and mothballs). Based on results of ambient monitoring studies published so far, a new hygiene-based exposure limit of 1.5 mg naphthalene per cubic metre of air (0.3 ppm) is proposed. Furthermore, results from biological monitoring studies are summarised in this article. The internal burden was almost exclusively determined by means of the urinary metabolites 1-naphthol and 2-naphthol, but it is currently not possible for one to evaluate a biological tolerance level (BAT) or a biological exposure index (BEI). Based on the toxicokinetics and metabolism of naphthalene, the central question on its carcinogenicity is briefly sketched. Naphthoquinones play an important role in this context. Their adducts with macromolecules may be the parameters of choice for the estimation of effects to human health.

Environmental Exposure↗
PubMed2006

Relationship between repetitive work and the prevalence of carpal tunnel syndrome in part-time and full-time female supermarket cashiers: a quasi-experimental study.

OBJECTIVES: To investigate the prevalence of Carpal Tunnel Syndrome (CTS) in full-time and part-time supermarket cashiers exposed to a different weekly duration of biomechanical load. METHODS: All the 269 cashiers and 127 office workers were asked to participate. The protocol included ergonomic risk assessment, collection of personal and clinical data and bilateral electrodiagnostic study of the median nerve. CTS symptoms were defined as past and/or current nocturnal and/or diurnal numbness, tingling, burning or pain involving at least one of the first three fingers. Results were evaluated according to two case definitions based on current symptoms and on the combination of current symptoms and slowing of sensory conduction velocity from wrist to palm, respectively. Difference in proportions of CTS symptoms and cases was evaluated by the Pearson's chi-square (chi(2)) test, univariate and multivariate logistic regression analyses were performed to determine the impact of weekly exposure. RESULTS: The final female study population included 71 full-time cashiers, 155 part-time cashiers and 98 office workers. Ergonomic risk level was rated 5 for hand activity level and 4 for peak of force according to ACGIH. The intersection of the two values fell on the threshold limit value line, confirming the possible exposure to biomechanical risk factors for CTS. The prevalence of current CTS symptoms was higher among full-time (31.0%) than in part-time cashiers (19.3%) or controls (16.3%) (p = 0.055). A similar pattern was found for CTS past symptoms and cases. Univariate analysis showed that full-time cashiers had a 2.3 fold increased risk for CTS specific current symptoms than control subjects. A similar trend also emerged for CTS cases but was not significant (Odds ratios 1.23). Multivariate logistic regression analysis confirmed the increased risk for CTS current symptoms in full-time cashiers. CONCLUSIONS: Intensive manual work associated with inadequate recovery time might have generated an impairment of the median nerve at the wrist level proportionally increasing with duration of hand use. Our study can provide useful information both for ergonomic risk assessment and work organization.

Adult↗
PubMed1987

[Smell threshold levels of substances as a criterion for evaluating the maximum permissible exposure levels].

Compared in the paper are the threshold limit values (TLV) and odour threshold concentrations (OTC) of 85 substances. As so far the generally accepted methods of odour nuisance measurements have been missing; the TLV/OTC ratio was adopted as a criterion of possible appearance of odour discomfort. The substances were divided into groups according to their feasibility of odorous nuisance. It was demonstrated that the odour discomfort might appear even with concentrations below TLVs. This particularly refers to styrene, naphthalene, CS2, pyridine and H2S.

Air Pollutants, Occupational↗
PubMed1995

Strategy of biological monitoring and setting of biological threshold limits (BAT values) in Germany.

Biological monitoring is of fundamental importance in Germany. The successful strategy of biological monitoring is based on four factors. Recommendations for the pre-analytical phase have been issued by official societies. For the analyses in blood and urine specimens around 100 methods have been recommended and standardized. All measurements must be carried out under a quality control scheme issued by the German Ministry of Labor and organized by the German Society of Occupational and Environmental Medicine. The occupational medical judgement of the biological monitoring results take place by "Biological Tolerance Values for Working Materials" (BAT values) and "Exposure Equivalents for Carcinogenic Working Materials" (EKA values). A BAT value is, by definition, the maximum allowable concentration for an individual which should be exceeded; 53 BAT values for 37 agents or groups of agents and 18 EKA values for 10 compounds have been defined. These values have been published since 1982 in an annual list of occupational standards. Every BAT or EKA value is based on extensive scientific documentation.

Environmental Monitoring↗