Working Conditions and Exposure to Dust and Bioaerosols in Sisal Processing Factories in Tanzania

Abstract

Information was collected on working conditions and personal exposures to dust, bacteria, and fungi in sisal fiber processing factories in Tanzania to identify health hazards and possible needs for preventive measures. Walkthrough surveys were performed in the brushing and decorticating departments of six sisal factories. The number of departments showing adequate scores for ergonomics and work organization, physical working environment, and occupational health items were determined. Personal thoracic dust samples were collected during sisal processing and analyzed for concentration of dust (n = 24) and for fungi and bacteria (n = 32). In both departments, most items considered to be a prerequisite for a good working environment were either missing or inadequate. Ergonomic and physical hazards were observed. Repetitive strenuous tasks, awkward work postures, and high noise levels were found. Visible dust and inadequate ventilation were seen in the brushing departments, and wet floors were observed in the decortication departments. Personal protective equipment was hardly used. The arithmetic mean exposure of sisal processors was 1.2 mg thoracic dust/m³, 43 × 10⁶ bacteria/ m³, and 2.35 × 10⁶ fungal spores/m³. The highest exposure levels were measured in the decortication departments when machines were cleaned of waste. Significant differences were found for mean thoracic dust exposure and bacteria counts between the brushing and decortication departments and the security guards. Within individual departments, there were no significant differences in exposures between the different work tasks. A linear mixed effect model of thoracic dust including department as fixed effect explained 65% of the between-worker variability for thoracic dust exposure. The study shows that workers in sisal processing in Tanzania are exposed to bioaerosols, and suitable control measures should be implemented. More exposure studies are needed in this type of industry.

Keywords:

• Bioaerosols
• checklist
• exposure assessment
• exposure variability
• sisal
• walkthrough survey

ACKNOWLEDGMENTS

The authors thank Dr. Gøran Lidén for technical details on the modification of the Casella cyclone (SIMPEDS). We are grateful to Bjørg Eli Hollund and the entire team at X-lab Bergen; Lene Madsø, and Per Ole Huser at the National Institute of Occupational Health, in Oslo, Norway, for their technical assistance during preparation of filters and further analyses. We thank all estate owners and workers in the surveyed estate for their voluntary participation, and the Norwegian Council of University Committee for Development Research and Education (NUFU) for financing this study.

Notes

^A Observed and/or reported.

^A NA, not applicable to the particular department.

^B PPE, personal protective equipment.

^C Only adequate skin personal protective equipment, not respiratory personal protective equipment.

^D IEC, information, education, and communication.

^E Designated eating place observed in only one estate.

^A ANOVA between departments.

^B ANOVA between workers tasks.

^C Sorting and grading fibers task was not sampled for bacteria and fungi.

^D NP, not possible to test.

^A ß, regression coefficients.

^B SE, standard error of the coefficients.

^C wwδ, within-worker variance.

^D bwδ, between-worker variance.

^E % bwδ, percentage of between-worker variance explained by the fixed effect(s).