Studies of airborne asbestos fiber concentrations associated with various operations of the drywall taping process have been undertaken in the province of Alberta, Canada. The results show that mixing, sanding and sweeping created high levels of airborne asbestos dust. The measured concentrations were frequently in excess of occupational health standards. Sanding in particular was assessed the most hazardous operation. The results are discussed in light of present and proposed Occupational Health Standards, and in terms of its implications for other workers, household contacts, and consumer's risk. Measures to reduce and control the health hazards associated with the process are described.

Air Pollutants↗

PubMed1968

The role of gastric juice in the pathogenesis of acute cholecystitis: an experimental study.

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Animals↗

PubMed1967

Diseased gallbladder: a follow-up study of operative results.

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Adult↗

PubMedDate not supplied

Measurement of benzene in the workplace and its evolution process, Part I: Overview, history, and past methods.

Benzene and its measurement continues to be important in the field of industrial hygiene. This two-part article reviews the history of occupational and environmental sampling and analysis of benzene from the early 1900s to the present. Part I provides an overview and details of the methods used in the past; history of the American Conference of Governmental Industrial Hygienists' threshold limit values for benzene; and reviews portable, grab, and integrated sampling methods as well as the various analytical methods. It is important to review and understand the past in order to predict future trends.

Air Pollutants, Occupational↗

PubMedDate not supplied

Measurement of benzene in the workplace and its evolution process, Part II: Present methods and future trends.

This article (the second of a two-part series) provides a discussion of currently accepted methodology and possible future happenings regarding measurement of benzene in workplaces. The gap between occupational and environmental monitoring is becoming narrow. Environmental levels will always be lower than the occupational, but as the push for lower threshold limit values continues, the focus should be on the environmental aspect as the ultimate limiting factor with respect to measurement. The charcoal tube/carbon disulfide desorption procedure is slowly being stretched to its limit with respect to benzene. It may be time for serious consideration in North America regarding adoption of the proven European procedure of thermal desorption using a porous polymer tube for analysis of benzene.

Air Pollutants, Occupational↗

PubMedDate not supplied

Benzene and total hydrocarbon exposures in the upstream petroleum oil and gas industry.

Occupational exposures to benzene and total hydrocarbons (THC) in the Canadian upstream petroleum industry are described in this article. A total of 1547 air samples taken by 5 oil companies in various sectors (i.e., conventional oil/gas, conventional gas, heavy oil processing, drilling and pipelines) were evaluated and summarized. The data includes personal long- and short-term samples and area long-term samples. The percentage of samples over the occupational exposure limit (OEL) of 3.2 mg/m3 or one part per million for benzene, for personal long-term samples ranges from 0 to 0.7% in the different sectors, and area long-term samples range from 0 to 13%. For short-term personal samples, the exceedance for benzene is at 5% with respect to the OEL of 16 mg/m3 or five parts per million in the conventional gas sector and none in the remaining sectors. THC levels were not available for all sectors and had limited data points in others. The percentage exceedance of the OEL of 280 mg/m3 or 100 parts per million for THC as gasoline ranged from 0 to 2.6% for personal long-term samples. It is recommended that certain operations such as glycol dehydrators be carefully monitored and that a task-based monitoring program be included along with the traditional long- and short-term personal exposure sampling.

Benzene↗

PubMedDate not supplied

Adjustment of occupational exposure limits for unusual work schedules.

A review of literature relating to the issue of adjustments of occupational exposure limits for unusual work shifts and unusual work schedules is described. The important issues relating to various adjustment models are discussed, and a number of conclusions are drawn. Tables of adjustment factors for 34 specific contaminants for 2 unusual schedules are given. A simple approach for use by industrial hygienists is proposed.

Air Pollutants, Occupational↗

PubMedDate not supplied

A method for the analysis of butyltin chlorides in air by gas chromatography with atomic emission detection.

An initial screening test compared the use of tropolone (2-hydroxy-2,4-6-cycloheptatrienone) in acetic acid with sodium diethyldithiocarbamate (NaDDC) as chelating agents for the extraction of butyltin chlorides from glass fiber filters and XAD-2 resin tube. NaDDC was chosen for subsequent analyses. Mono-, di-, and tributyltin chloride were spiked onto glass fiber filters and XAD-2 resin, extracted in toluene with NaDDC and derivatized with pentylmagnesium bromide. Derivatized butyltin species were determined by gas chromatography with plasma atomic emission detection. Glass fiber filters and XAD-2 resin were found to provide high retention of butyltin compounds during sampling and efficient recovery of butyltin compounds by extraction with NaDDC.

Air Pollutants, Occupational↗

PubMedDate not supplied

Benzene and total hydrocarbons exposures in the downstream petroleum industries.

A review of studies, including both articles published in peer-reviewed journals and reports that were not peer reviewed, regarding occupational exposure to benzene and total hydrocarbons in the downstream petroleum industry operations was performed. The objective was to provide a broad estimate of exposures by compiling exposure data according to the following categories: refinery, pipeline, marine, rail, bulk terminals and trucks, service stations, underground storage tanks, tank cleaning, and site remediations. The data in each category was divided into personal occupational long-term and short-term samples. The summarized data offers valuable assistance to hygienists by providing them with an estimate and range of exposures. The traditional 8-hour time-weighted average (TWA) exposure and the 40-hour workweek do not generally coincide with exposure periods applicable to workers in marine, pipeline, railcar, and trucking operations. They are more comparable with short-term exposure or task-based exposure assessments. The marine sector has a large number of high exposures. Although relatively few workers are exposed, their exposures to benzene and total hydrocarbons are sometimes an order of magnitude higher than the respective exposure limits. It is recommended that in the future, it would be preferable to do more task-based exposure assessments and fewer traditional TWA long-term exposure assessments within the various sectors of the downstream petroleum industry.

Air Pollutants, Occupational↗

PubMedDate not supplied

Exposure estimation in the presence of nondetectable values: another look.

A common problem faced by industrial hygienists is the selection of a valid way of dealing with those samples reported to contain nondetectable values of the contaminant. In 1990, Hornung and Reed compared a maximum likelihood estimation (MLE) statistical method and two methods involving the limit of detection, L. The MLE method was shown to produce unbiased estimates of both the mean and standard deviation under a variety of conditions. That method, however, was complicated, requiring difficult mathematical calculations. Two simpler alternatives involved the substitution of L/2 or L/square root of 2 for each nondetectable value. The L/square root of 2 method was recommended when the data were not highly skewed. Although the MLE method produces the best estimates of the mean and standard deviation of an industrial hygiene data set containing values below the detection limit, it was not practical to recommend this method in 1990. However, with advances in desktop computing in the past decade the MLE method is now easily implemented in commonly available spreadsheet software. This article demonstrates how this method may be implemented using spreadsheet software.

Air Pollutants, Occupational↗

PubMedDate not supplied

Ultrasound guided percutaneous nephrostomy for obstructive uropathy in benign and malignant diseases.

OBJECTIVE: Analyze the success rate, complications and overall benefit of ultrasound guided percutaneous nephrostomy (PCN) for the relief of obstructive uropathy in benign and malignant diseases. MATERIALS AND METHODS: PCN was performed in 50 kidneys of 32 patients. It was performed in emergency rooms totally under ultrasound guidance by general surgeons. Seldinger technique was used in all cases. Changes in renal function after the procedure were analyzed using paired t-test. RESULTS: The procedure was successfully completed in 42 out of 50 kidneys (84%). There has been no major complication and 28% minor complications. The renal function improved significantly when PCN was performed for benign conditions (mean creatinine 3.52 mg/dL before and 2.18 mg/dL after PCN), however in malignancy there has been no significant improvement in renal function (before PCN mean creatinine 6.39 mg/dL and after PCN 5.41 mg/dL). CONCLUSION: We conclude that PCN can be effectively performed under ultrasound guidance and should be the initial procedure in acutely obstructed kidneys with pyonephrosis and poor renal function. In malignant cases, however, improvement in renal function is possible only if the procedure is carried out at an early stage.

Adolescent↗