Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Threshold Limit Values”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed1991

[Health problems among persons exposed to grain dust].

This review describes health problems in persons primarily exposed to grain dust. The main epidemiological investigations from the nineteen seventies and eighties are reviewed. The commonest complaints were mucus membrane irritation. In the majority of investigations, an excess incidence of chronic bronchitis was encountered and it cannot be disproved that asthma developed in a number of the employees. Influenza-like symptoms compatible with the organic dust syndrome have been described in several investigations from silos but allergic alveolitis has not been described in this branch. The latter condition has been encountered in farm workers working with mouldy grain. With dust concentrations of about the Danish threshold limit value, many health problems still occur. The following prophylactic measures are recommended: Effective drying of corn before storage, effective ventilation and cleaning and covering of dusty working procedures. Epidemiological investigations are proposed in the Danish raw material sector to illustrate health problems related to grain dust. These investigations should be combined with qualitative and quantitative occupational hygienic measurements of dust.

Agricultural Workers' Diseases↗
PubMed1991

[Occupational bronchitis].

Industrial bronchitis is defined as a chronic bronchitis due to prolonged exposure to polluted air at the professional workplace. Up until the nineteen eighties, its proper existence was open to controversy, because outside professional factors, such as tobacco, were considered as predominant causes. However, the most recent epidemiological studies have shown that exposure to dust, in conjunction or not with fumes and gases, was responsible for chronic obstructive syndromes. Bronchitis observed in silicotic patients is an interesting example. On the other hand, in other occupations, such as soldering, in which only gases and fumes are inhaled, the risk of chronic obstructive bronchitis is minimal. Due to the threshold limit values enforced by law since many years in Switzerland, the probability of industrial bronchitis is low; therefore the proportional responsibility of tobacco as cause of pulmonary obstruction is increased and justifies preventive effort also in this field.

Air Pollutants, Occupational↗
PubMed1991

Ultrastructural changes in rat lungs exposed to combinations of cadmium, zinc, copper, and nickel.

The morphological effects of single intratracheal intubation of cadmium oxide (CdO) with oxides of zinc (Zn), copper (Cu), and nickel (Ni) at their threshold limit values on alveolar macrophages and type II cells were studied. The combinations used were: CdO + ZnO (0.1 mg + 5.0 mg); CdO + CuO (0.1 mg + 0.2 mg); and CdO + NiO (0.1 mg + 1.0 mg). Rats sacrificed after one week recovery period showed distinct morphological changes. Alveolar macrophages and type II cells exposed to CdO and ZnO showed an increase in number, shape, and size of vacuolar phagolysosomes. Multivesicular bodies and lamellar bodies were also seen, as well as the lack of distinct nucleoli. The CdO/CuO combination showed an increase in the number of dense vacuolar phagolysosomes and large aggregates of multivesicular bodies. Hypertrophy of mitochondria was also evident in this combination. The CdO/NiO combination showed more distinctive changes compared to the other two combinations in lysosomes, membranous whorls, multivesicular bodies, residual bodies, and number of mitochondria. Our findings using combination exposures of CuO and ZnO with CdO indicate the existence of competitive inhibition resulting in some form of protective action. On the other hand, the CdO/NiO exposure seemed to be additive showing structural modifications, premature aging, faster degeneration, and release of abnormal membrane structures.

Animals↗
PubMed1990

[Evaluation of the biological exposure test "CS2 in urine"].

The necessity of integration of biological exposure tests, for example the BET "CS2 in urine", is shown in connection with the activities of the works doctor in order to evaluate the individual health risk of the exposed workers. The possibilities on principle for the tests are discussed Topical biological threshold limit values for CS2 in urine on the base of validity studies are presented. In addition a special intervention regime.

Air Pollutants, Occupational↗
PubMed1990

[Pollution of indoor air in large-scale kitchens and laundries by volatile halogenated hydrocarbons].

The study demonstrates that the agents used for dishwashing and in the central laundry are already slightly contamined with halogenated hydrocarbons and formaldehyde. Analyses of the washing lyes yield considerably higher concentrations of halogenated hydrocarbons. Especially in the dishwater a relatively high concentration of trichloromethane (chloroform) was detected. Obviously these halogenated hydrocarbons are also present in relatively high concentrations in the air of the corresponding working places. However, the concentrations of individual halogenated hydrocarbons and formaldehyde are clearly below the respective threshold limit values.

Air Pollutants, Occupational↗
PubMed1978

[Diseases caused by diisocyanates. 1. Irritation of the respiratory system and skin].

Toluylene diisocyanate (TDI) has an uncommon importance in the production of irritation of respiratory system. In the last few years less volatile isocyanate compounds have been substituted for TDI. Commercial available diphenylmethane diisocyanate (MDI) and polymethylene polyphenyl isocyanate (PAPI) were analyzed in 1971. The analysis indicated the presence of 21% TDI in several samples. It is evident, with respect to the relatively high vapor pressure of TDI, that such impurities will be able to cause air concentrations in excess of the current threshold limit value (TLV) of 0.02 ppm. Liberation of TDI by heat from varnish insulinations is a difficult problem. This problem was described as "an old hazard in new guise". Especially, in a soldering process on polyurethane coated wire, excess of TLV is possible in unfavourable conditions. By the regulation that the concentration of TLV must not exceed 0.02 ppm and by the use of new non-volatile isocyanate the risk of acute and subacute intoxications has considerably subsided. Chronic irritations of respiratory system and asthma-like diseases, however represent still an unsolved problem.

Cyanates↗
PubMed1990

[Occupational respiratory tract allergies].

Numerous occupation-related substances of plant, animal, microbial and chemical origin are potent immunogens and allergens. In the Federal Republic of Germany, the most common form of occupational obstructive airways disease is baker's asthma, caused by the inhalation of flour dust and other related substances. Compliance with the industrial threshold limit values (TIL) at the workplace reduce the risk of contracting disease, but cannot exclude it completely. Apart from obtaining a detailed history, and performing a physical examination, the diagnostic work-up also requires inclusion of special allergy tests (prick, intradermal, RAST)--in equivocal cases also, after a prior exposure--free preparatory period, re-exposure and inhalative work-place-related provocative testing. Therapeutically, elimination of exposure heads the list of measures; in concrete terms, this can also mean a change of occupation or even occupational re-training.

Allergens↗
PubMed1990

[Permissible dermal exposure dose and safety level for herbicide residues as an occupational hygiene standard for the evaluation of exposure].

At preparing mixtures for spraying, application of pesticides and entering treated areas workers are subject of potential exposure, more than 90% via skin. The limitation of dermal exposure requires hygiene-toxicological threshold limit values. On the basis of toxicity data from experiments with animals a permissible dermal exposure dose for pesticide residues is determined. For that a safety and a resorption factor are used, which are fixed in dependence on the toxic effects. The permissible dermal exposure dose is the basis of the calculation of a safety value for residues on plant surfaces and reentry time.

Environmental Exposure↗
PubMed1990

[Biological monitoring at the work site].

To evaluate the standard of industrial hygiene whilst dealing with pathogenic substances, threshold limit values, (TL-Values) have to be observed. This strategically important preventive concept is being supplemented by a secondary preventive measure. This is legally based on Section 8. Workers' Protection Act (physical aptitude of workers), Federal Ordinance Nr. 39/1974 regarding the physical aptitude of workers for specified jobs. The determination of pathogenic substances or their metabolites in body fluids, therefore, constitutes a possibility to evaluate the individual health hazard. In addition, the problems of the test concept to evaluate the effects of exposure to polycyclic aromatic hydrocarbons by means of determining DNA-PAH adducts are discussed.

Air Pollutants, Occupational↗
PubMed1989

[Adequate measurement of artificial mineral fibers and evaluation of the biological effect].

Epidemiological and clinical medical examinations of exposed workers to man-made mineral fibers (MMF) to fix threshold limit values are presupposed by adequate measurements of MMF-dust. As yet are used technics which are unsatisfying. In consideration of the biological conditions in the breathing system a draft to measure MMF dust is introduced and proved. This draft based on the use of two-step-gravimetrical measurements together with membranous filter devices and evaluation by an electronic microscope.

Air Pollutants, Occupational↗
PubMed1989

Study on the health hazards of scrap metal cutters.

Scrap metal cutters seemed to be left out in most preventive programmes as the workers were mainly contract workers. The health hazards of scrap metal cutting in 54 workers from a foundry and a ship breaking plant were evaluated. Environmental sampling showed lead levels ranging from 0.02 to 0.57 mg/m3 (threshold limit values is 0.15 mg/m3). Exposure to lead came mainly from the paint coat of the metals cut. Metal fume fever was not reported although their main complaints were cough and rhinitis. Skin burns at all stages of healing and residual scars were seen over hands, forearms and thighs. 96% of the cutters had blood lead levels exceeding 40 micrograms/100 ml with 10 workers exceeding 70 micrograms/100 ml. None had clinical evidence of lead poisoning. The study showed that scrap metal cutting is a hazardous industry associated with significant lead exposure. With proper medical supervision, the blood lead levels of this group of workers decreased illustrating the importance of identifying the hazard and implementing appropriate medical surveillance programmes.

Adult↗
PubMed1977

[Exposure to mercury in public dental clinics in Oslo--an occupational hazard evaluation].

To evaluate the occupational hazard in use of mercury by dentists, the work environment and procedures of 22 dentists and their 33 assistants were surveyed. Determinations were made of a) the mercury vapour concentrations in the offices b) the urinary excretion of mercury by the 55 persons concerned c) the mercury concentration in blood. In three of the offices surveyed, mercury vapour concentration exceeded the threshold limit value of 0.05 mg/m3, implying a lack of care in handling mercury. Urinary mercury contents of one dentist and four dental assistants exceeded 0.05 mg/l i.e. the upper "normal" value for a population with no known exposure to mercury. The manner in preparation and handling of the amalgam were considered to be the predominant comtamination factor.

Air Pollutants↗
PubMed1989

[Exposure of women to chemical solvents during work at chemical plants and its relation to various biochemical parameters].

The studies covered 211 women employed at a Technical Articles Plant in exposure to chemical solvents, such as: methyl alcohol, benzyl alcohol, methylene chloride, ethyl acetate, acetone, carbon tetrachloride, xylene, toluene, n-amyl acetate. The workplaces were ventilated and the concentrations of vapours did not exceed Threshold Limit Values (TLVs). Arithmetic means did not reveal any exposure to chemicals at particular plant divisions, which was also confirmed by the indices of admissible concentrations of chemicals or their metabolites in biological fluids (ABC--admissible biological concentrations). Morphological tests of blood and enzymatic determinations in their mean values did not indicate any toxic effects. On the other hand, individual analysis of every working woman demonstrated deviations from the values of the parameters determined. The changes referred mostly to the duration of coagulation, bleeding and methanol absorption, which points to the need for prevention and protection of the working women against occupational hazards.

Adolescent↗
PubMed1989

Occupational exposure limits for carcinogens--variant approaches by different countries.

The differences in treatment of occupational exposure limits for carcinogens by 24 countries is described along with a discussion of the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLV) treatment, the similar treatment of the new Occupational Safety and Health Administration (OSHA) standard, and the treatment by provinces of Canada. The unique listing by the Federal Republic of Germany of so-called technical guiding concentrations of a group of carcinogens is discussed with the note that Austria used this same system. Publications on justification for establishing occupational exposure limits for certain carcinogens are discussed also.

Canada↗
PubMed1988

Toxicity assessment of hydrazine fuels.

The major health aspects of exposure to hydrazine propellants are reviewed. Toxic effects of hydrazine fuels on humans and animals as well as in vitro studies are discussed with emphasis on recent findings and USAF studies. Propellant hydrazines have been found to be genotoxic in in vitro studies and oncogenic in animal studies. Embryotoxicity has been demonstrated at very high exposures but not at occupationally encountered levels for hydrazine and unsymmetrical dimethylhydrazine. Epidemiologic evidence to support these findings is lacking; however, the results of animal and in vitro studies have resulted in lowering both the time-weighted average-threshold limit values and short-term exposure limits for these propellants.

Aerospace Medicine↗
PubMedDate not supplied

[Mercury levels in urine and head hair of dental personnel].

As dentists and their assistants are usually exposed to mercury in their clinical practices. The objective was to investigate the mercury level in these dental personnel. Urine and head hair samples were collected from 201 dental personnel and 57 unexposed controls for mercury analysis. The mercury content was analyzed by using cold vapour atomic absorption spectrophotometry. The results showed that mercury levels in the urine and head hair of dental personnel were significantly higher than in the controls (P less than 0.01). The urine mercury concentration of the unexposed controls ranged from 0.1-10.0 micrograms/l (means = 2.6 +/- 0.29 micrograms/l). The highest urine mercury level was found in the group of dental assistant (means = 17.1 +/- 2.44 micrograms/l). The mean urine mercury levels found in dentists, dental students and dental technicians were 10.1 +/- 1.42, 11.1 +/- 1.69 and 3.2 +/- 0.69 micrograms/l respectively. The amounts of urine mercury from dental assistants, dentists and dental students were 81.0%, 38.2% and 43.5% higher than the threshold limit value respectively. The mean head hair mercury concentration of unexposed controls ranged from 0.3-12.2 micrograms/g (means = 2.8 +/- 0.36 micrograms/g). The highest head hair mercury concentration was found in the group of dental assistant and 6th year dental students (means = 10.1 +/- 0.84 and 10.5 +/- 3.2 micrograms/g). The mean head hair mercury levels found in dental assistants, dentists, dental students and dental technicians were 10.1 +/- 0.84, 7.5 +/- 1.2, 6.5 +/- 1.54 and 2.8 +/- 0.53 micrograms/g respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Assistants↗
PubMed1987

[Evaluation of manganese exposure of workers engaged in the production of manganese ferroalloys].

Manganese concentrations were determined in the ferromanganese plant. In 300 stationary and individual samples manganese was determined by pulse polarography (sensitivity-0.007 mg/m3, precision-10%). The present manganese concentrations are lower than those from earlier studies. Over 50% workers are exposed to manganese concentrations slightly exceeding threshold limit values (TLVs) (0.09-0.43 mg/m3). The other workers are exposed to concentrations several times higher than the TLVs (0.82-1.91 mg/m3). At some workplaces lead concentrations were also determined. TLVs for lead were not surpassed. In result of the use of anodic mass in arc furnaces, the occurrence of polycyclic aromatic hydrocarbons (PAH) is thought possible. Recommendations related to monitoring and selection of workplaces with the same exposures for medical estimation were given. Possible risks for people living near the plant were pointed out.

Air Pollutants, Occupational↗
PubMed1987

Total concentrations of dust in the air during farm work.

Total concentrations of dust in the air of work environments were measured on 20 Finnish farms during 1980-82. On 8 farms the main line of production was dairy farming, on 5 farms it was pig farming, on 4 farms poultry farming and on 3 farms grain production. Dust was measured by the gravimetric method according to the Finnish standard. Results were compared to the threshold limit value (TLV), which for inorganic dust is 10 mg/m3, and for organic dust 5 mg/m3. Mean concentrations of dust in the breathing zone exceeded the TLV for organic dust in all farm buildings, piggeries and poultry yards with coops having the highest mean concentrations, 12.6 mg/m3 and 12.8 mg/m3, respectively. Mean total concentrations of dust during seed dressing, harrowing, rolling and emptying the grain drier were 31.4, 14.0, 18.2 and 20.0 mg/m3, respectively. During sowing and haymaking, the total concentrations of dust were also high occasionally.

Agricultural Workers' Diseases↗