Quantitative Microbial Risk Assessment (QMRA) of Workers Exposure to Bioaerosols at MSW Open Dumpsites

Area of Science:

• Environmental Microbiology
• Occupational Health
• Risk Assessment

Background:

• Dumpsite workers are exposed to bioaerosols, including pathogenic microorganisms.
• Quantifying infection risks from specific bioaerosols is crucial for occupational health.
• Previous studies highlight potential health hazards in dumpsite environments.

Purpose of the Study:

• To compute the infection risk for dumpsite workers exposed to Aspergillus fumigatus and Escherichia coli O157:H7.
• To model the transport of inhaled bioaerosols within the human respiratory system.
• To integrate dose-response models for estimating respiratory and gastrointestinal infection risks.

Main Methods:

• Utilized bioaerosol exposure data from Akpeimeh, Fletcher, and Evans (2019).
• Employed a stochastic (Markov Chain) model for inhaled dose transport.
• Integrated a beta-Poisson dose-response model to estimate infection risks.

Main Results:

• Workers engaged in scavenging, waste sorting, and monitoring face respiratory and GI infection risks of 10⁻¹ after 11 hours.
• GI infection risks varied by location (active, dormant, entrance, boundary) and pathogen-indicator ratios (1:10³ and 1:10⁴).
• Respiratory infection risks were consistently high (magnitude of 10⁻¹) across all assessed locations.

Conclusions:

• Estimated risks of respiratory and gastrointestinal infections are high for all assessed activities at the dumpsite.
• Specific locations within the dumpsite present varying levels of GI infection risk.
• Findings underscore the need for enhanced protective measures for dumpsite workers.