Using a model of risk perception which divides the community into attitudinal and behavioural subgroups based on awareness, concern and action in relation to a waste management facility, we conducted a survey in a community with an operating landfill and a ten-year history of controversy over the unsuccessful siting of a hazardous waste facility (HWF). The purpose of the survey was to study community attitudes to waste management in general, attitudes specific to landfills and HWFs, and to identify factors which shape community attitudes in both cases. Levels of concern and activism were lower for the landfill; activism and concern were more likely among younger subjects and those with children. In the case of the HWF, greater concern and activism were more likely among married people and those without a university education. Gender differences in relation to environmental "concern" were not found for either the landfill or the HWF siting attempts.
Three cross-sectional surveys were conducted in different regions of British Columbia, using a model of risk perception that divides the community into attitudinal and behavioral subgroups based on awareness and concern about waste management facilities. The three communities differed with respect to their levels of both awareness and concern about facilities, either planned for or situated in their region. Surprisingly, the most polarized community, which had nevertheless accepted a facility, rated this facility as more desirable than the other two communities. The unconcerned group in this community felt well informed, was more trusting of siting and operating agencies, and believed that the facility would generate benefits. The concerned group in this community also felt better informed, was more trusting of siting and operating agencies, and believed that its facility would generate benefits, compared with concerned groups in the other two communities. Longitudinal studies of the attitudes driving the siting process are needed to understand how these relationships evolve over time.
In epidemiologic studies, much of the variation in disease risk estimates associated with occupational pesticide exposure may be due to variation in exposure classification. The authors compared five different methods of using interview information to assess occupational pesticide exposure in a US-Canada case-control study of neuroblastoma (1992-1994). For each method, exposure assignment was compared with that of a reference method, and neuroblastoma effect estimates were calculated. Compared with the reference method, which included a complete review of occupation, industry, job tasks, and exposure-specific activities, the use of occupation-industry groups alone or in combination with general job task information diluted the exposed group by including individuals who were unlikely to have been truly exposed. The effect estimates representing associations between each exposure method and neuroblastoma were different enough to influence the study's conclusions, especially when the exposure was rare (for maternal occupational pesticide exposure, the odds ratio was 0.7 using the reference exposure assessment method and 3.2 using the occupation-industry group exposure assessment method). Exposure-specific questions about work activities can help investigators distinguish truly exposed individuals from those who report exposure but are unlikely to have been exposed above background levels and from those who have not been exposed but are misclassified as exposed because of their employment in an occupation-industry group determined a priori to be exposed.
This study tested the reliability and validity of industry- and mill-level expert methods for measuring psychosocial work conditions in British Columbia sawmills using the demand-control model.
In the industry-level method 4 sawmill job evaluators estimated psychosocial work conditions at a generic sawmill. In the mill-level method panels of experienced sawmill workers estimated psychosocial work conditions at 3 sawmills. Scores for psychosocial work conditions were developed using both expert methods and applied to job titles in a sawmill worker database containing self-reported health status and heart disease. The interrater reliability and the concurrent and predictive validity of the expert rater methods were assessed.
The interrater reliability and concurrent reliability were higher for the mill-level method than for the industry-level method. For all the psychosocial variables the reliability for the mill-level method was greater than 0.90. The predictive validity results were inconclusive.
The greater reliability and concurrent validity of the mill-level method indicates that panels of experienced workers should be considered as potential experts in future studies measuring psychosocial work conditions.
Adipose tissue from a sample of 41 British Columbians was analyzed for a number of organochlorine pesticides. Pesticide concentrations were very low. Persistent fat-soluble compounds like DDT were found at the highest concentrations, whereas compounds that either quickly metabolize to other forms or are readily excreted were found at low levels or not detected. Data on age, sex, area of residence, occupation, diet and weight were obtained by interview. Increasing age was related to increasing levels of several of the persistent pesticides. Although there were insufficient data for statistical analysis, two individuals with potential occupational exposures had much higher levels of the pesticides than other subjects. Although population-based surveys of these organochlorine pesticides in human tissue may have little value, further study may be warranted for groups known to have had high exposures (e.g. occupationally exposed).
Due to concerns over glutaraldehyde's toxicity, two substitutes have recently been introduced; ortho-phthalaldehyde (OPA), and a mixture of hydrogen peroxide and peracetic acid. There is limited information about the health effects for employees from these products. This study assesses the current practices regarding the use of high-level disinfectants in British Columbian hospitals and predicts the relative toxicities of each product. Industry practices were compiled using a comprehensive survey of current practices and decision processes in all hospitals in British Columbia. Of 95 hospitals, 64 returned surveys; 80% of these used high-level disinfection. Among user hospitals, 49% used glutaraldehyde alone and 51% had introduced alternatives. Concern about staff health was the most common reason for substituting, but this was frequently not considered when choosing specific alternatives. Hospitals that involved occupational health, infection control or regional staff in high-level disinfectant decisions used glutaraldehyde alternatives less often. In most hospitals, it was difficult to find individuals who were knowledgeable about the use of disinfectants. Potential health effects associated with each type of high-level disinfectant were assessed by review of the published literature and available manufacturers' data along with qualitative structure-activity relationship analysis. Results indicated that although all products irritate the skin and respiratory tract, OPA is a potential dermal and respiratory sensitizer but hydrogen peroxide and peracetic acid do not cause allergic reactions. Despite little being known about the risks to employees from glutaraldehyde alternatives, their use is widespread. The potential risks of all high-level disinfectants are serious; thus regulators and users are faced with important risk management decisions before and after they have been introduced into the workplace.
Micronuclei in peripheral blood lymphocytes from British Columbia seasonal farmworkers and controls were evaluated using the cytokinesis-block technique. The farmworkers harvested berry crops and were likely occupationally exposed to pesticides. Subjects were 39 female subjects of South Asian descent; 18 farmworkers employed during 1993 and 21 age-matched controls. The mean age was 55.9 years. Micronuceli were also scored for the presence of kinetochores. No significant difference was found between the frequency of micronucleated binucleates in the farmworkers group (19.20/1000 binucleates), and the control group (21.76/1000 binucleates). However, among the farmworkers employed in 1993, there was a positive, but not statistically significant, association between micronucleated cell frequency and weeks worked: 16.44/1000 binucleates in those working less than 20 weeks; 23.78/1000 binucleates in those working 20 to 23 weeks; and 25.43/1000 binucleates in those working more than 23 weeks. In those who had ever been employed as farmworkers, there was an elevated frequency of micronucleated cells in the group with the longest history of employment as a farmworker (25.28/1000 binucleates) compared to those with the shortest employment history (16.48/1000 binucleates). This trend remained evident after adjusting for age, red blood cell folate, meat consumption, coffee consumption and recent vaccination. A positive association between the consumption of meat and micronucleus frequency was also observed. Non-meat eaters were likely life-long vegetarians. Micronuclei in farmworkers had a lower frequency of kinetochore positive micronuclei than controls. This study indicates that South Asian berry pickers in British Columbia may be at risk for genetic damage. More studies in other ethnic groups and in males are needed to generalize the findings of this study. More direct measures of exposure are needed to elucidate the sources of genotoxicity.
In a lumber mill in the northern inland region of British Columbia, Canada, we measured inhalable particulate, resin acid, and monoterpene exposures, and estimated wood dust exposures. Potential determinants of exposure were documented concurrently, including weather conditions, tree species, wood conditions, jobs, tasks, equipment used, and certain control measures. Over 220 personal samples were taken for each contaminant. Geometric mean concentrations were 0.98 mg/m3 for inhalable particulate, 0.49 mg/m3 for estimated wood dust, 8.04 micrograms/m3 for total resin acids, and 1.11 mg/m3 for total monoterpenes. Multiple regression models for all contaminants indicated that spruce and pine produced higher exposures than alpine fir or mixed tree species, cleaning up sawdust increased exposures, and personnel enclosure was an effective means of reducing exposures. Sawing wood in the primary breakdown areas of the mill was the main contributor to monoterpene exposures, so exposures were highest for the barker operator, the head rig operator, the canter operator, the board edgers, and a roving utility worker in the sawmill, and lowest in the planer mills (after kiln drying of the lumber) and yard. Cleaning up sawdust, planing kiln-dried lumber, and driving mobile equipment in the yard substantially increased exposures to both inhalable particulate and estimated wood dust. Jobs at the front end of the sawmill where primary breakdown of the logs takes place had lower exposures. Resin acid exposures followed a similar pattern, except that yard driving jobs did not increase exposures.
The study's objectives were to measure flour antigen exposure in bakeries and define the determinants of exposure. Ninety-six bakery workers, employed in seven different bakeries, participated in the study. Two side-by-side full-shift inhalable dust samples were obtained from each study participant on a single occasion. The flour antigen exposure was measured as wheat antigen and fungal alpha-amylase content of the water-soluble fraction of inhalable dust, assayed via enzyme-linked immunosorbent assays. During the entire sampling period bakers were observed and information on 14 different tasks was recorded at 15-minute intervals. Other production characteristics were also recorded for each sampling day and used in statistical modeling to identify significant predictors of exposure. The mean alpha-amylase antigen exposure was 22.0 ng/m3 (ranging from below the limit of detection of 0.1 ng/m3 to 307.1 ng/m3) and the mean wheat antigen exposure was 109 micrograms/m3 (ranging from below the limit of detection of 1 microgram/m3 to 1018 micrograms/m3). Regression models that explained 74% of variability in wheat antigen and alpha-amylase antigen exposures were constructed. The models indicated that tasks such as weighing, pouring, and operating dough-brakers increased flour antigen exposure, while packing and decorating resulted in lower exposures. Croissant, puff-pastry, and bread/bun production lines were associated with increased exposure, while cake production and substitution of dusting with the use of divider oil were associated with decreased exposure. Exposure levels can be reduced by the automation of forming tasks, alteration of tasks requiring pouring of flour, and changes to the types of products manufactured.