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At least 109 records · Page 6Linked to original sources
PubMed1999

A comparison of minimum detectable and proposed maximum allowable soil concentration cleanup levels for selected radionuclides.

Regulations on the release of a radioactively contaminated site for unrestricted use are currently being established by the Environmental Protection Agency. The effective dose equivalent rate limit for the reasonably maximally exposed individual was proposed at 0.15 mSv y(-1). The purpose of this study is to investigate whether or not maximum allowable soil concentrations of common radionuclides corresponding to 0.15 mSv y(-1) are readily detectable. These maximum allowable soil concentrations were estimated using RESRAD. The RESRAD estimates account for an effective dose equivalent rate from external radiation plus the committed effective dose equivalent rate from internal radiation delivering 0.15 mSv y(-1) to the reasonably maximally exposed individual. For Michigan and Arizona soil, the minimum detectable activities were calculated for a few radionuclides and compared to the RESRAD estimated maximum allowable concentrations. Considering only gamma-ray spectroscopy, this study found no evidence that concentrations of gamma-ray emitting radionuclides in soil contributing to 0.15 mSv y(-1) were undetectable.

Arizona↗
PubMed1997

Concentration of cadmium in rice and urinary indicators of renal dysfunction.

OBJECTIVES: (1) To examine the relation between concentrations of cadmium (Cd) in rice and urinary concentrations of indicators of renal dysfunction and the prevalence of abnormalities in urine in areas polluted by Cd. (2) To establish the maximum allowable concentration of Cd in rice from these findings. METHODS: The target population consisted of 1703 inhabitants (832 men and 871 women) aged over 50 years who consumed home grown rice and had lived in the same hamlet in areas polluted by Cd in the Kakehashi River basin in Ishikawa Prefecture, Japan for at least 30 years. The correlation coefficients between concentrations of Cd in rice and several urinary substances, the prevalence of abnormalities in urine and sex in hamlets polluted by Cd were calculated. Finally, regression analysis was performed for significant indicators to calculate the maximum allowable concentration of Cd in rice based on values in a control group. CONCLUSIONS: Significant correlations between concentration of Cd in rice and concentrations of urinary beta 2-microglobulin, metallothionein, glucose, and aminonitrogen were established. Similarly, there were significant correlations between concentration of Cd in rice and the prevalence of beta 2-microglobulinuria, metallothioneinuria, glucosuria, proteinuria, proteinuria with glucosuria, and aminonitrogenuria. The highest maximum allowable concentration of Cd in rice calculated for these indicators was 0.34 ppm/l and 0.29 ppm/g creatinine. Both values are lower than 0.4 ppm, the tentative limit prescribed by the Japanese government.

Aged↗
PubMed1998

Occupational effects on the health of workers and laboratory technicians in petrochemical plants.

A study was conducted over a 3-year period on the morbidity in petrochemical plants producing xylene, benzene, phenol and acetone, and in the related service laboratory. The incidence rate of system and target organ disorders due to the adverse effects of benzene, toluene, xylene, phenol, acetone, etc., was calculated. The exposure to chemical hazards (except benzene) of plant workers was not high--the concentrations were below the maximum allowable concentrations (MACs) and the duration of contact was not longer than 270 min per 8-h shift. The duration of exposure for laboratory technicians (all female) comprised an entire 8-h working shift, but concentrations of the chemical substances did not exceed MACs. The incidence rate of system and target organ disorders as a total of all production plants was 6% on average over the 3-year period, and for laboratory workers it was 10.3%. The average total incidence rate (comprising all diseases) was 42% in the production plants and comparatively greater in the laboratory--56% as an average for the period. Since laboratory technician posts are well mainly by women in Bulgaria, recommendations are to minimize contact with chemical hazards for women of child-bearing age, as was the case for benzene.

Chemical Industry↗
PubMed1993

Impact of organochlorine pesticide residues and PCBs on otters (Lutra lutra): a study from western Britain.

A study of otter (Lutra lutra) populations and levels of organochlorine (OC) pesticide residues and PCBs in otter droppings (spraints) was made on eight stretches of river in three catchments in Wales and West Midland England. Population and contaminant levels were compared against target values. The otter populations (as measured by an index) remained stable on one stretch over 11 years, while they increased rapidly to equilibrium on four other stretches. The three lower stretches of rivers showed more erratic trends and on only one stretch did the index exceed, occasionally, the target value. Marking intensity at spraint sites was also lower at the three lowland sites. Concentrations of dieldrin, DDE and PCBs were significantly greater in spraint samples from the three lowland stretches. Over 50% of samples from the three lowland stretches had OC concentrations above the maximum allowable concentration, whereas most samples from the upland stretches had concentrations below the 'no effects level'. It is suggested that the colonization, by otters, of their former lowland range is inhibited by OC contamination of their food chain but, if contaminant levels can be reduced, spread will occur rapidly.

Animals↗
PubMedDate not supplied

[The validation of the maximum permissible concentration of pyromellitic dianhydride in the atmosphere].

The maximum allowable concentration (MAC) of pyromellitic acid dianhydride (PMAD) in the ambient air was substabtiated by physiological, hematological, and physiological methods. The inhalation of this substance by animals reduced their body weight, erythrocytic osmotic resistance, enhanced animals' sensitization. The mean daily MAC of PMAD was found to be 0.01 mg/m3. PMAD was considered to be Hazard Class 2.

Administration, Inhalation↗
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↗
PubMed1993

[A study of hygienic standard for titanium in the source of drinking water].

The smell and taste thresholds of titanium in water were tested. The results indicated that the concentration of smell and taste thresholds for Titanium were 4.329mg/L and 3.332mg/L respectively. The threshold below value of autopurification was 0.1mg/L. The toxicity assessment showed that the acute toxicity of titanium by oral route was of low order according to the toxicity classification. There was no obvious cumulative effect, nor was there mutagenesis demonstrable. Chronic toxicity test of titanium in rats showed that the maximum non-effective concentration was 1.08mg/L. It is suggested that the maximum allowable concentration of titanium in drinking water may be 0.1 mg/L.

Animals↗
PubMed2000

Analytical control of preservative labelling on skin creams.

Contents of 23 preservatives (22 permitted and 1 non-permitted) were analysed in 67 skin creams to verify whether these products complied with the Cosmetic Directive with respect to ingredient labelling, as well as with respect to maximum allowed concentrations of the respective preservatives. The preservatives selected for the analysis were: parabens, 2-phenoxyethanol, benzoic acid, 4-hydroxybenzoic acid, sorbic acid, salicylic acid, formaldehyde and formaldehyde releasers, 3:1 mixture of 5-chloro-2-methyl-4-isothiazolin-2-one and 2-methyl-4-isothiazolin-2-one (Kathon CG), 2-bromo-2-nitropropane-1,3-diol (Bronopol), 5-bromo-2-nitro-1,3-dioxane (Bronidox) and methyldibromo glutaronitrile. 1 or more parabens were present in 87% (n=58) of the investigated products, 2-phenoxy ethanol in 49% (n=33) of the products, and formaldehyde/formaldehyde releasers were present in 51% (n=34) of the products. Kathon CG was found in 3 products, acid preservatives (except salicylic acid) in 8 products, Bronopol in 5 products, and methyldibromo glutaronitrile was present in 4 products. The contents of all of the target preservatives in the skin creams were within the maximum allowed concentrations of the respective substances. Incorrect ingredient labelling with respect to paraben content was found in 10% (n=7) of the investigated products, 33% (n= 22) of the products were not declared for the content of formaldehyde/formaldehyde releaser, and 7% (n=5) products were incorrectly labelled for the content of 2-phenoxyethanol. In 1 of the products containing Kathon CG, the ratio of 5-chloro-2-methyl-4-isothiazolin-2-one to 2-methyl-4-isothiazolin-2-one (1.4:1) was not correct. 4 of the 8 products containing acid preservatives were not labelled for the content of these substances. All in all, in 45% (n=30) of the investigated skin creams ingredient labelling was incorrect with respect to preservative contents. The proportion of incorrect labelling is reduced to 23% (n = 15), when the formaldehyde content in skin creams below 30 ppm is not accounted.

Chromatography, High Pressure Liquid↗
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↗
PubMed2001

Effect of benzene, toluene, xylene on the semen quality and the function of accessory gonad of exposed workers.

The effects on semen and the function of accessory gonad of workers after short and long term exposure to benzene, toluene, and xylene were examined. The semen and blood of 24 married workers exposed to benzene, toluene, and xylene were collected. Routine sperm characteristic, acrosin activity, and Lactate dehydrogenase C4 (LDH-C4) relative activity were detected. The results showed that benzene, toluene, and xylene were found in the blood and semen of some ex-workers at workplaces where the air concentration of benzene, toluene, and xylene exceeded the maximum allowable concentration (MAC). No such solvents were detected in the blood and semen of workers of the control group. The sperm vitality and sperm motility decreased in the exposed workers. The mean acrosin activity, gamma-GT activity and LDH-C4 relative activity in the exposed workers were lower, and fructose concentration was higher than those in the control. There were negative correlations between sperm vitality, sperm activity, acrosin activity, or LDH-C4 relative activity and working history. These results suggest that the mixture of these solvents could affect the sperm and the function of accessory gonad. This might be one reason of the abnormal pregnancy outcome among the wives of workers exposed to benzene, toluene, and xylene.

Acrosin↗
PubMed1999

Effect of benzene, toluene, xylene on the semen quality of exposed workers.

OBJECTIVE: To examine the effects on semen and sperm quality of workers after a short and long term exposure to benzene, toluene, and xylene. METHODS: The semen and blood of 24 married workers exposed to benzene, toluene, and xylene from shoemaking, spray painting, or paint manufacturing factories were collected. The concentration of benzene, toluene, and xylene in the blood and semen was determined by using headspace chromatographic method. Routine sperm test was carried out and acrosin activity detected. RESULTS: The results showed that benzene, toluene, and xylene were found in the blood and semen of some ex-workers in a working environment where the air concentration of benzene, toluene, and xylene exceeded the maximum allowable concentration (MAC). This result was not found in workers of the control group. There were also some effects on the quality of semen in the exposed workers. For example, the percentage of semen with liquefaction time exceeding 30 minutes increased. The sperm vitality, motility and acrosin activity decreased. At the same time, there were a positive correlation between liquefaction time and the level of toluene in semen, and a negative correlation between sperm vitality, sperm activity or acrosin activity and working history. CONCLUSIONS: The results suggested that the mixture could affect the quality of semen and sperm, which might be the main reason of the abnormal pregnancy outcome among the wives of workers exposed to benzene, toluene, and xylene. Further studies are, however, required to confirm these findings.

Acrosin↗
PubMed1994

Volatile organic contaminants found in the habitable environment of the Space Shuttle: STS-26 to STS-55.

The health and performance of spacecraft crews can be adversely affected by contaminants present in the respirable air. Contaminants originate from hardware offgassing, crew and microbial metabolism, use of utility chemicals, leakage from fluid systems and payload experiments, and from electrical overheating. The quality of Shuttle air is measured by collecting contaminants in evacuated cylinders or on sorbent resin for later ground-based analysis by gas chromatography (GC) and GC mass spectrometry (MS). The results of those analyses are presented for 28 missions, including 5 Spacelabs which were flown in the payload bay of the Shuttle. The major contaminants were relatively nontoxic alcohols (ethanol, isopropanol), ketones (acetone, diacetone alcohol), alkanes, halocarbons (Halon 1301, Freon 113), and siloxanes. Occasionally, more toxic contaminants, such as methanol, acetaldehyde, and tetrachloroethene, were present at low concentrations (below 1 mg/m3). The contaminant concentrations measured in spacecraft air were compared to spacecraft maximum allowable concentrations (SMAC's) which are set to protect the crew from adverse health effects or performance decrements. Aggregate toxicity assessments (T values) of the contaminants present during each mission, calculated by summing the ratios of measured concentrations to each contaminant's SMAC, showed that air quality consistent met the criterion that the T value be less than 1.

Air Pollution, Indoor↗