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PubMedDate not supplied

[Setting a maximum allowable concentration for urea in reclaimed potable water and evaluating the nature of its biological action].

The purpose of the study was to identify maxim allowable concentrations of urea in reclaimed potable water. The urea concentration equal to 80 mg/l is the threshold dose influencing the taste and flavor of water. Urea is a low toxicity substance (LD50 = 14,300 mg/kg), the effect of which is not cumulative. However, when used in high doses it affects bioenergetic and cholinergic processes and causes changes in ECG, higher nervous activity and visceral structure. It has been shown that when applied to warm-blooded animals the acting dose of urea is 14.3 and 1.43 mg/kg (1/1000 and 1/10000 LD50), the threshold dose is 0.72 mg/kg (1/20000 LD50), and the ineffective dose is 0.36 mg/kg (1/40000 LD50) which amounts to the concentration of 10 mg/l. In terms of toxic effects the dose equal to 10 mg/l is taken to be the maximally allowable concentration of urea. It is recommended to use the Laham biotest for measuring urea in water.

Animals↗
PubMed1991

[Experimental substantiation of maximum allowable concentration of phosphoric acid in the water of reservoirs].

It has been found out on the basis of experimental studies, that the threshold concentration of phosphorous acid is 85.7 mg/l according to the influence on organoleptic water properties, I mg/l--according to the influence on the sanitary regimen of water reservoirs. The preparation is of low toxicity when administered perorally to laboratory animals, cumulation degree is medium. Embryotoxic and gonadotoxic effects, mutagenic and allergic properties have not been detected. The maximum no-effect dose in the chronic experiment is 1.4 mg/kg. MAC is recommended on the level of I mg/l according to the general sanitary indicator of harmfulness (the 3-d class of danger).

Animals↗
PubMed1990

[Substantiation of the mean working day maximum allowable concentrations of dusts with differing degrees of fibrogenesis].

On the basis of developed by the author mathematical models of pneumoconiosis morbidity and of methodological techniques of dusts dividing according to the degree of fibrogenesis under exposure to various concentrations of dusts differing in fibrogenesis. In the author's opinion, working conditions can be considered safe if the probability of pneumoconiosis does not exceed 0.1% for the 40 years length of working. On this basis mean working day concentrations, at which the probability of the development of the mentioned disease does not exceed 0.1%, are proposed as mean working day MACs. Average working day MACs for the whole range of dusts fibrogenesis have been calculated. The obtained in this way average working day MACs for the least fibrogenic dusts equal 6 mg/m3, and for the most fibrogenic dusts - 0.2 mg/m3.

Air Pollutants, Occupational↗
PubMed1991

[Data for the establishment of maximum allowable concentration of chlorophenoxypinacoline in the working zone air].

Chlorophenoxypinacoline with its acute intragastric toxicity LD50 can be attributed to the 3rd class compounds of hazardousness (moderate hazardous substances). Local irritation and skin resorption effects were not revealed. Irritation of the mucous in the eyes in rabbits was moderate and functional cumulation was insignificant. Average lethal concentration (LC50) was not attained. The threshold of acute inhalation and irritation action (Limac, Limir) was at 1093 mg/m3, the threshold of chronic inhalation action (Limch) was at 165.2 mg/m3. No signs of specific mutagenic and embryotropic action were found. The accepted MAC for chlorophenoxypinacoline in the working zone air is 10 mg/m3. The aggregate condition aerosol, 3rd degree of hazardousness.

Air Pollutants, Occupational↗
PubMed1979

[Modular way of sampling for determination of the degree of occupational exposure at industrial plants with periodically changing dust concentration].

A work station with dustiness changing periodically during a workshift is one of the most common types of work stations, as regards exposure dynamics. Cyclic significant concentrations of dust occurring from time to time result from a specific technological treatment used. The measuring module will be the time of measurement, starting with the beginning of the cycle of working out a given detail or--the technological process through the whole treating and technological process as well as breaks--due to various reasons--until starting another, analogous operation. What was found is that average dust concentrations obtained from modular measurements correspond to average concentration to which an employee is exposed during the whole workshift. Modular measurements allow to reconstruct work conditions inducing silicosis, and may be helpful in settling the maximum allowable concentration.

Air Pollutants↗
PubMed1991

[Effect of simultaneous exposure to fluorine and manganese on health status of workers].

The effect of fluorine and manganese on the health of workers continually exposed to these elements was studied. The concentration of the chemicals did not significantly exceed maximum allowable concentrations only during three hours of work daily. Thirty-six workers directly exposed to fluorine and manganese were examined and compared with the controls. The authors demonstrated that exceeding permissible norms did not cause evident intoxication symptoms even though working in exposure had lasted for many years. However, some changes in the activity of liver indicatory enzymes may be one of the first symptoms of this organ's damage. Frequently occurring ++periodontosis and leukoplakia of the mucous membrane needed careful stomatological prophylaxis .

Adult↗
PubMed1976

Subchronic inhalation toxicity of azinphos-methyl in rats.

Azinphos-methyl was evaluated for its subchronic inhalation toxicity. The exposure of rats to concentrations of 0.195, 1.24, and 4.72 mg/m3, respectively, for 12 weeks, 6 hrs daily, 5 times weekly, resulted in effects only in those animals which inhaled aerosols of the highest concentration. This group showed a significant depression of the cholinesterase activity in plasma and erythrocytes. The males of this group had a lower body weight gain. The results are in agreement with the established maximum allowable concentration of 0.2 mg/m3.

Aerosols↗
PubMed1990

[Substantiation of hygienic standard of lincomycin in the air of the work area].

The main parameters of lincomycin toxicometry were studied in animals. It was shown that the compound was low toxic after its oral or intraperitoneal administration in single doses, had no local irritant and skin resorptive effects and did not accumulate. The allergenic properties were slightly pronounced. The intoxication picture after a single inhalation was characterized by renal dysfunction, erythropenia, neutrophilia, lymphopenia and impairment of the normal intestinal microflora. The zone of the specific antimicrobial effect was equal to 8. On chronic inhalation, the signs of the specific antimicrobial effect were of the paramount importance: Limch am was equal to 4.7 mg/m3 and Limch exceeded 18.3 mg/m3. In the concentrations used, the substance had no embryotoxic and gonadotropic effects. The level of 0.5 mg/m3 (for Hazard Class 2) was recommended and approved as the maximum allowable concentration.

Air Pollutants, Occupational↗
PubMed1990

[Current state of knowledge regarding prenatal effects of benzene].

The present knowledge concerning the possible prenatal effect of benzene and/or its metabolites is presented. Animal experimental results and epidemiological studies proved to be completely insufficient. The physical, chemical and biochemical properties of this ubiquitously occurring solvent, especially the specific effects on the erythropoetic system including the damage of the cyto skeleton of the cells, require an enhanced attention in the cases of exposure of female workers in child bearing age and of pregnant women to benzene, even in cases of surely observing the maximum allowable concentration at work places.

Abnormalities, Drug-Induced↗
PubMed1990

[Health hazards due to lead in an an accumulator-production plant of the Suhl district].

In a lead accumulator producing factory the health risk of workers has been studied for more than 30 years by means of measuring the lead concentration at the working places for many years and by carrying out several exposure tests on the 22 workmen. At most workshop places the maximum allowable concentration was considerably exceeded. In many workmen the concentration of lead in the blood and the delta aminolevulinic acid in the urine were increased above the control values. Since 1955 six occupational diseases have been diagnosed which demonstrates the high health risk.

Air Pollutants, Occupational↗
PubMedDate not supplied

[Hygienic standardization of methyl salicylate in the air of workplace].

A complex toxicological study of methyl salicylate was done. Threshold level at 8 mg/m3, and maximum allowable concentration of methyl salicylate at 1 mg/m3 (2-nd class of chemical hazard, with remark of'harmful in contact with skin') for the air of working zone were estimated. Maximum single and daily average allowable concentrations in ambient air at level 0.01-0.005 mg/m3 were calculated.

Air Pollutants, Occupational↗