Assessment of home care aides' respiratory exposure to total volatile organic compounds and chlorine during simulated bathroom cleaning: An experimental design with conventional and "green" products.

Home care (HC) aide visits to clients' homes often involve cleaning and disinfecting (C&D) bathrooms. Some ingredients in C&D household products are associated with respiratory illness, including sodium hypochlorite (bleach) and quaternary ammonium compounds (quats). "Green" products may be safer for the environment, however there are limited quantitative evaluations of their respiratory risks. This study assessed airborne concentrations and time profiles of total volatile organic compounds (TVOC) and chlorine generated during typical bathroom cleaning performed by aides using conventional and green products. Aides performed cleaning tasks in a simulated residential bathroom constructed in an environmental air sampling laboratory. A balanced experimental design involved each aide coming to the lab for four visits during which she performed two 20-min cleaning sessions using one of three C&D products (bleach-based, 1-5% sodium hypochlorite by weight; quats-based, 0.1-1% by weight quaternary ammonium compounds; and "green," 0.05% by weight thymol, a component of botanical thyme oil) or distilled water as a control. TVOC and chlorine direct reading instruments were attached to aides with sample inlets located in the breathing zone. Ten-second averages of TVOC and chlorine gas concentrations and instantaneous peak concentrations were recorded for the sessions' duration. TVOC concentrations by methods of C&D application (spraying, streaming, wiping) also were evaluated. The study completed 169 air sampling sessions with 22 aides. The quats-based product generated more than twice the average TVOC concentrations (mean = 1,210 ppb) than the bleach-based (mean = 593 ppb) or green (mean = 498 ppb) products. Each product generated TVOC concentrations that rose rapidly within the first few minutes of application. Spraying produced the highest TVOC exposures, wiping the lowest. Thirteen aides (65%) experienced peak chlorine exposures above the OSHA PEL ceiling limit (1 ppm) when using the bleach-based product. HC aides may experience respiratory hazards from use of conventional or green C&D products formulated with bleach or other respiratory irritants and sprayed in small, poorly ventilated spaces typical of bathrooms. Spraying should be avoided.

Healthy Aging Requires a Healthy Home Care Workforce: the Occupational Safety and Health of Home Care Aides.

PURPOSE OF REVIEW: To identify important home care (HC) aide occupational safety and health (OSH) hazards and examine how addressing these can improve aide health and the delivery of HC services overall. Specifically, this review seeks to answer: Why is HC aide OSH important? What are the most significant OSH challenges? How can improving HC aide OSH also improve the safety and health of their clients? What implications do the findings have for future research? RECENT FINDINGS: HC is one of the fastest growing US industries. Aides comprise its largest workforce and are increasingly needed to care for the rapidly aging population. There is an aide shortage due in part to instabilities in HC work organization and to serious job-specific hazards, resulting in aides losing work time. Recent social, economic, and technological factors are rapidly changing the nature of HC work, creating OSH hazards similar to those found in nursing homes. At the same time, aides are experiencing social and economic inequities that increase their vulnerability to OSH hazards. These hazards are also a burden on employers who are challenged to recruit, retain, and train aides. OSH injuries and illness interrupt the continuity of care delivery to clients. Many OSH hazards also put HC clients and families at risk. A new framework and methodologies are needed to assess aide and client safety together in order to guide future HC research, policies, and practices. Government, industry, and labor commitment is needed to fund and coordinate a comprehensive, multidisciplinary research program.

Escherichia coli plasmid production in fermenter.

Escherichia coli harboring a recombinant plasmid was grown in a fermenter to study the effects of selected process parameters on the growth of the microbe and on plasmid amplification with chloramphenicol treatment. Eighteen fermentations were carried out according to a statistical experimental design in which the fermentation temperature, pH, and turbidity of culture at the onset of plasmid amplification were the selected independent process variables. Static regression models describing the process were derived from the experimental results. It turned out that recombinant plasmid copy numbers could be influenced by controlling fermentation temperature and pH. The maximal copy number during bacterial growth phase and the optimal plasmid production were found to require fermentation conditions different from those needed for optimal bacterial growth and cell division. The conditions also differed significantly from those routinely used in research laboratories for plasmid preparation. The chloramphenicol treatment increased the plasmid copy number compared with chromosome numbers up to fivefold. Some of the data suggest that under certain conditions the number of chromosome molecules in E. coli cells may rise during the plasmid amplification stage. Statistical experimental design, a nucleic acid sandwich hybridization technique for plasmid quantification, and regression models proved to be useful in this study.

Studies on growth and cardenolide production of Digitalis lanata tissue cultures.

Digitalis lanata cell cultures grown as small undifferentiated aggregates in suspension culture can be redifferentiated into green embryos that produce cardenolides. The possibility of using a statistical (Box-Wilson) experimental design to study the effects of four different variables on growth, differentiation, and cardenolide production of D. lanata tissue cultures are investigated. The results of the analyses were processed by linear regression analysis. Mathematical models explaining the effects of the variables were developed. The concentration of maltose and the NO(3) (-)--NH(4) (+) ratio were found to be significant variables for both growth and cardenolide production. The size of the inoculum was also important.