David E. Clapp

Semen quality in papaya workers with long term exposure to ethylene dibromide

To examine whether long term occupational exposure to ethylene dibromide (EDB) affects semen quality a cross sectional study of semen quality was conducted among 46 men employed in the papaya fumigation industry in Hawaii, with an average duration of exposure of five years and a geometric mean breathing zone exposure to airborne EDB of 88 ppb (eight hour time weighted average) and peak exposures of up to 262 ppb. The comparison group consisted of 43 unexposed men from a nearby sugar refinery. Statistically significant decreases in sperm count per ejaculate, the percentage of viable and motile sperm, and increases in the proportion of sperm with specific morphological abnormalities (tapered heads, absent heads, and abnormal tails) were observed among exposed men by comparison with controls after consideration of smoking, caffeine and alcohol consumption, subjects age, abstinence, history of urogenital disorders, and other potentially confounding variables. No effect of exposure to EDB on sperm velocity, the overall proportion of sperm with normal morphology, or YFF bodies was observed. These data strongly suggest that EDB may increase the risk of reproductive impairment in workers at exposure levels near the National Institute for Occupational Safety and Health recommended limit of 45 ppb (as an eight hour time weighted average) and far below the current standard of the Occupational Safety and Health Administration of 20 ppm.

A cytogenetic study of papaya workers exposed to ethylene dibromide

Ethylene dibromide (EDB) has been shown to be carcinogenic in animal studies and mutagenic in vitro. One cytogenetic study of workers exposed to low levels of EDB for short durations was negative. To test whether exposure to low levels of EDB over long periods caused cytogenetic changes, we have assessed the frequencies of sister-chromatid exchanges (SCE) and chromosomal aberrations (CA) in the peripheral blood lymphocytes of 60 men occupationally exposed to EDB. These men worked in papaya-packing plants where EDB was used to fumigate the fruit after harvest to kill fruit-fly larvae. 42 other men who worked at a nearby sugar mill served as controls. The average duration of exposure of the papaya workers was 5 years. 82 full shift personal breathing-zone air samples indicated that the papaya workers were exposed to a geometric mean of 88 ppb of EDB, as an 8-h time weighted average (TWA). Peaks up to 262 ppb were measured. The proposed OSHA 8-h TWA for EDB is 100 ppb, while NIOSH recommends 45 ppb. No differences in SCE levels were found between exposed and nonexposed workers. No differences were found in the total CA frequency between exposed and nonexposed workers. SCE levels were significantly increased in men who smoked cigarettes (p = 0.0001) and in men who smoked marijuana (p = 0.01). CA levels showed a significant increasing trend with age (p = 0.03).

Ventilation design by microcomputer

The design of ventilations systems is an arduous task if done by hand. This paper describes an interactive computer program for the Apple II Microcomputer which virtually eliminates the manual calculations while providing the additional power and flexibility of computer processing. Ventilation designs can be reworked numerous times with final designs stored on diskette for later recall, review, and possible redesign. The computer program prompts the user through the design process in a logical step by step manner. Most design data is contained in the program and the user only needs a schematic drawing of the layout and a selection of hoods including exhaust volume, duct velocity, and entry losses. The program requires an Apple II Microcomputer with 48 K of RAM and at least one disk drive. Aversion of the program for the TRS-80 Model I or III is also available.

Urinary 4,4′-Methylenebis (2-Chloroaniline) (MBOCA): A Case for Biological Monitoring

Abstract 4,4-Methylenebis (2-chloroaniline), also known as MBOCA (or MOCA®), is an aromatic amine that is absorbed primarily through the skin. MBOCA is used as a curing agent in the castable polyurethane industry. It has also been identified as a suspect human carcinogen. Because of concerns that airborne monitoring would not truly assess the degree of worker absorption of MBOCA, the Polyurethane Manufacturers Association, an association of MBOCA users, implemented a voluntary biological monitoring program 15 years ago to assess and reduce worker exposure to MBOCA. Review of biological monitoring data, generated during the past 6 years using high performance liquid chromatography methods, has shown trends in reduced urinary MBOCA concentrations and thus reduced worker exposure. In addition, the results of the biological monitoring program, indicating worker exposure, have prompted the industry to initiate programs to reduce MBOCA exposure by engineering controls. The design of closed transfer systems in 1...

Linking microcomputers and dedicated word processing systems for increased productivity

Abstract With the decline in cost of hardware, more and more professionals are acquiring personal computers at their desk. Most common uses of these office computers are word processing and spreadsheet (e.g. LOTUS 123, MULTIMATE, FRAMEWORK, etc. 1 ) applications. Professionals typically generate text directly on the personal computer (in lieu of hand written copy) and use spreadsheet programs to tabulate and analyze collected field data. A problem in some offices is integrating text and data prepared on the personal computer with existing dedicated word processing systems which have existed in many office environments for some time. One solution is to have the text and tabulated data retyped into the word processing system, however, this approach is not an effective use of resources. The Industrial Hygiene Section, Industrywide Studies Branch (DSHEFS), NIOSH has developed procedures for electronically linking personal microcomputers with an office-wide word processing system. Using a commercially available hardware “board” (which may be inserted into an open slot in an IBM-PC or compatible), the rough copy report and tabulated spreadsheet data can be electronically linked and “uploaded” from a microcomputer to the word processing system. At NIOSH, a WANG word processing system is the office-wide system for preparing and publishing final reports. This system is not readily compatible with IBM-PC (or similar) microcomputers; however, using MULTIMATE (a commercially available word processing program) and the hardware board, documents can be readily transferred to the WANG virtually unchanged from the copy generated on the microcomputer. Importantly, spreadsheet data can be similarly transferred and linked to a document on the WANG wordprocessing system. This paper describes the sequence of steps, along with necessary hardware and software, to achieve the integration of written documents and numerical data (analyzed by LOTUS 123) from a microcomputer to a office-wide WANG word processing system.