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At least 163 records · Page 9Linked to original sources
PubMed2001

Safety issues associated with processing soybeans in an enclosed habitat intended for long-duration space missions.

Soybeans have been selected to be grown in a habitat (BIO-Plex, Bioregenerative Planetary Life Support Systems Test Complex) designed to evaluate advanced life support systems for long-duration space missions. Soymilk and soy bread will be incorporated into this nutritious, plant-based food system. Because all consumables will be recycled and reused, food safety is a particular concern. Critical control points were identified to control microbiological hazards, particularly mycotoxins, and chemical hazards from antinutrients and volatiles emitted during processing of soymilk and soy bread. Volatile compounds, evolved during the manufacturing of soymilk and soy bread, were quantified by GC/MS to assess their impact on this closed loop system. All concentrations of volatiles evolved during soymilk production were below the 24-h Space Craft Maximum Allowable Concentration (SMAC), while acetaldehyde surpassed the SMAC criteria for soy bread. Recommendations were made for processing of soybeans in such environments to minimize risk to crew member health.

Acetaldehyde↗
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↗
PubMed1980

[Incidence of pneumoconiosis in welders in semiautomatic systems in the light of environmental studies].

Several years' measurements of the concentration of dusts and welding fumes, in one of metallurgic plants revealed the mean dust concentration of 3.6 mg/m2 at automatic welding workplace. At semiautomatic welding in CO2 screening the expected concentrations was 10 mg/m3, single measurements concentrations ranging from 0.6 mg/m3 to 140 mg/m3. A similar mean value was obtained from 6 Provincial Sanitary--Epidemiologic Stations. Analysis of data collected at 9 Provincial Sanitary--Epidemiologic Stations indicated that pneumoconiosis prevalence among welders operating semiautomatic equipment in CO2 screening was not higher than the prevalence among welders using screened electrodes. For dusts and welding fumes, the maximum allowable concentration value has been recommended.

Air Pollutants↗
PubMed1995

Inorganic components of drinking water and microalbuminuria.

Relatively little is known of the chronic effects attributable to the ingestion of inorganic components such as uranium and silicon. Although ingestion of large amounts of U can cause acute renal damage through a chemical effect, studies on humans have typically considered inhalation the route of exposure. We investigated the association between drinking water concentration levels of U and Si, and microalbuminuria, a sensitive biological indicator of renal dysfunction. Linear regression analysis revealed a statistically significant association between U cumulative exposure index and albumin per mmol creatinine (P = 0.03). No such significant relationship appeared for Si, although a positive trend was witnessed. Since normal but increasing levels of microalbuminuria were observed at U concentration levels below the Canadian Maximum Allowable Concentration (MAC), it is suggested that further study be undertaken.

Adolescent↗
PubMed2005

Deposition and depletion of five anticoccidials in eggs.

Anticoccidials are compounds that are widely used as feed additives to prevent and treat coccidiosis. They are licensed for use in a prescribed concentration and during a certain time interval for broilers and pullets but not for laying hens. It was shown in the past that carry-over at the feeding mill is found to be the main reason for the presence of residues in eggs. An animal experiment was set up to investigate the effect of carry-over at the feeding mill on the presence of residues of anticoccidials in eggs. For the compounds diclazuril, robenidine, halofuginone and nicarbazin in combination with narasin, two concentration levels were tested: the maximum allowed concentration for broilers (100%) and a concentration corresponding to 5% carry-over during feed preparation. Also dimetridazole was included in the experiment but only at one concentration level. Eggs were sampled during treatment (14 days) and for a period of 30 days after withdrawal of the anticoccidial-containing feed. Residues were determined, and deposition and depletion curves were generated. Analyses were performed by ELISA and LC-MS/MS. For all compounds, substantial residues could be found in the 5% groups, which points out the risk of carry-over at the feeding mill. The distribution of the residues between egg yolk and white was determined by analyzing both fractions.

Animal Feed↗
PubMed2003

Pilot-scale evaluation of select nitrate removal technologies.

Due to the extensive application of artificial nitrogen-based fertilizers and animal manure on land, many water agencies face problems of increasing concentrations of nitrate in groundwater. The contamination of groundwater by nitrate may pose a significant public health problem. The threat of methemoglobinemia is well documented and reflected in the US drinking water standard of 10 mg/L as nitrate-nitrogen. Approximately 45% of Saskatchewan's population use groundwater for drinking purposes, out of which, approximately 23% (230,000) are rural residents. The water used is made available from over 48,000 privately owned wells in regions where there is an extensive application of chemical fertilizers. Biological denitrification, ion exchange, and reverse osmosis (RO) processes were selected for a field study. Field studies were conducted on these processes. The sulfur/limestone autotrophic denitrification (SLAD) process was selected to achieve biological removal of nitrate from groundwater. The feasibility of the system was evaluated under anaerobic conditions. An ion exchange study was conducted using Ionac A554 which is a strong anion exchange resin. In the case of groundwater containing low sulfate concentrations, A554 offered high nitrate removal. However, the disposal of regenerant brine can be a problem. A reverse osmosis unit with Filmtec membrane elements (FT30-Element Family) was used in the study on nitrate removal. The unit effluent average nitrate concentration was less than the maximum allowable concentration.

Bioreactors↗
PubMed1994

Ethanol induced modification of m-xylene toxicokinetics in humans.

This study was undertaken to determine whether previous subacute treatment with ethanol could modify the kinetics of m-xylene in humans. A group of six volunteers was exposed twice to either 100 or 400 ppm of m-xylene during two hours (between 0800 and 1000). Ethanol was given orally in the early evening on each of two consecutive days before exposures (total ethanol intake of 137 g). Such ethanol pretreatment affected the kinetics of m-xylene but only at the high exposure (400 ppm). The modifications were: (1) decreased concentration of m-xylene in blood and alveolar air during and after exposure; (2) increased urinary excretion of m-methylhippuric acid at the end of exposure. Ethanol treatment also enhanced the elimination of antipyrine in saliva. Overall, this study showed that the effect of enzyme induction on the metabolism of m-xylene, after ethanol ingestion, depends on the exposure concentration and is not likely to occur as long as the exposure concentrations remain under the current maximum allowable concentration (100 ppm) in the workplace.

Adult↗
PubMed1997

[Contamination of the air at work sites during application of "Fastac 10EC" in fruit orchards].

The study of the air contamination was carried out in six fruit farms located in the region of Grójec and Warka. The measurements were carried out during the application of "Fastac 10EC" insecticide (alphamethrin) in fruit growing at work sites of tractor drivers operating the sprayers. The mean concentrations of alphamethrin at individual work sites were low and ranged between 0.001 and 0.0039 mg/m3 of the air. Due to the lack of maximum allowable concentration (MAC), the inhalation toxicity of alphamethrin of 320 mg/m3 (4-h), toxicity class of alphamethrin (III) and MAC of natural pyrethrum were considered. In this context the determined concentrations seem to be safe.

Agriculture↗
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↗
PubMed1993

[Lead in the environment of Poland].

Lead belongs to those elements which have a great variety of applications in the up-to-date technology. In the form of waste products or automotive wastes it has been brought into a global circulation. The authors attempt to present harmful effects of this "environmental poison" on individual media and human population in Poland. Following published and non-published data, an outline of lead geochemistry, anthropo-genetic sources of lead emission into the environment, concentration of lead in the ambient air, surface water, soil, plants and food, is presented. The data are interpreted on the basis of home maximum allowable concentrations and on the health criteria recommended by international organizations. It was found that the knowledge on the level of pollution of individual environmental media with lead is diversified and incomplete. This hinders a comparable and comprehensive evaluation of lead migration in the natural environment and thus the assessment of exposure magnitude among inhabitants of all regions (voivoships) of the country. Emissions from plants producing and processing non-ferrous metals, industrial waste sites, motor transport especially in central parts of urban and industrial agglomerations, and use of certain mineral fertilizers are recognized as the greatest hazards to the biosphere and human health among all sources of environmental pollution with lead. As appears from the data, the highest level of lead contamination of air, water and soil occurs in the central part of the Upper Silesian Industrial District as well as in the direct vicinity of other plants of non-ferrous metals in Katowice and Legnica voivodships. It was also noted that crops from those agglomerations and from family gardens located near active industrial waste sites or exploited yards may contain amounts of lead exceeding considerably allowable concentrations. It was revealed that in Polish conditions the largest amounts of lead enter children's organism with dirt, dust and food and the smallest with water. Vegetables and potatoes, and in the case of children, milk as well are the main carriers of lead in Polish food, therefore, these products should remain under particular laboratory control. It is acknowledged that preventive measures in areas where the level of environmental pollution with lead is not fully recognized, biological monitoring of lead concentrations in the blood of children, the most sensitive group of population, should be initiated.

Air Pollutants↗
PubMed1977

[Experimental substantiation of the maximum permissible concentration of Reglone in the air of a work environment].

Reglon (20 per cent dikwad dibromide) is an extensively used herbioide and desiccant. During acute and chronic inhalatory experiments on white rats, using 4--hour exposure to water aerosols, determination is made of the acute LC50 -- 83 mg/m3, of the acute threshold concentration - 9.9 mg/m3 acute substance, as well as of the chronic threshold concentration - 0.32 mg/m3. In all instances the clinical picture of intoxication is characterized by pulmonary lesion, and partial involvement of liver and kidneys. The computed zones of acute and chronic inhalatory toxicity warrant the assumption that no sequelae dueto herbicide cumulation in the organism should be expected. At safety coefficient 3, the authors propose 0.1 mg/m3 dikwad dibromide as a temporary limit of the maximum allowable concentration of reglon in the working environment air.

Air Pollutants↗
PubMed1990

[Substantiation of cyclophos MPEL in the soil].

On the basis of studies aimed at the substantiation of MAC for cyclophos in soil it was established, that subthreshold amounts of cyclophos according to the water-migration and air-migration indexes of harmfulness equal 0.03 mg per 1 kg of absolutely dry soil, according to the general sanitary index--0.1 mg/kg. Since cyclophos destruction period in plants is relatively short (8 days), there is no danger of translocation of the pesticide from soil in amounts exceeding the maximum allowable level for cyclophos in food stuffs. The pesticide migration in the system soil-plant was not determined. The water migration and air-migration indexes are the limiting indexes of harmfulness for cyclophos. 0.03 mg/kg is recommended as the maximum allowable concentration of cyclophos in soil.

Air Pollutants↗
PubMed1995

[Probability of health impairment by exposure to chemicals at the level of sanitary standards and the problem of individual sensitivity].

The paper briefly outlines the problems in estimating the probability of the population's health impairments caused to the individual person's hypersensitivity due do their genetic and their acquired properties when it is chemically exposed at the level of the maximum allowable concentrations. In connection with the environmental situation, it is quite necessary to concentrate everybody's attention on palliative antichemical protective measures.

Chemical Industry↗
PubMed1992

Exposure to dust, endotoxins, and fungi in the animal feed industry.

In the Dutch animal feed industry, approximately 6000 workers are exposed to organic dust, originating mainly from raw materials such as grain, pulses (peas and beans), and waste products from the vegetable oil and starch industries. In this study, 79 stationary dust samples and 530 personal dust samples from eight animal feed production facilities were analyzed. The stationary total dust samples showed gravimetric concentrations ranging from 0.2 to 25 mg/m3 (geometric mean [GM] 1.3 mg/m3). Concentrations of smaller particle fractions (respirable, thoracic, and inspirable dust) were considerably lower. Personal inspirable dust concentrations were considerably higher than stationary concentrations and were strongly related to job titles. Pooled personal inspirable dust concentrations ranged from 0.2 to 450 mg/m3 (GM = 2.4 mg/m3). After adjusting for differences between inspirable and total dust, 25% of the measurements exceeded the Dutch maximum allowed concentration (MAC) for total nuisance dust (10 mg/m3) and 42% exceeded the American Conference of Governmental Industrial Hygienists' threshold limit value for grain dust (4 mg/m3). Endotoxin concentrations ranged from 0.2 to 1870 ng/m3 inspirable dust (GM = 5.1 ng/m3). Endotoxin appeared to be less prevalent in respirable dust than in larger dust fractions. Concentrations in dust appeared to be related to stages in the production process. Colony-forming units (cfu) of fungi ranged from 130 to 15,300 cfu/m3 (GM = 2300 cfu/m3) and were in parallel measurements more strongly related to endotoxin concentrations than to dust concentrations. Clearly, workers in the Dutch animal feed industry are frequently exposed to dust levels above recommended Dutch and American levels. Exposure levels to endotoxin and to fungi are quantified.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗