Abundance and cultivable bioaerosol transport from a municipal solid waste landfill area and its risks

Municipal solid waste (MSW) landfills, constituting the third largest anthropogenic sources of bioaerosols, are suspected to be one of the major contributors to adverse health outcomes. A regional modeling of aerosol trajectories based on wind-tunnel observations and on-site monitoring was newly-developed to uncover the impacts of a typical MSW landfill on ambient bioaerosol pollution. Results showed that the horizontal diffusion velocity of bioaerosols reached 4.33 times higher than the vertical velocity under surface calm winds. On-site monitoring revealed that the concentrations of particulate matter (PM) with a diameter of 10 μm were 3.05 times higher than those of PM1.0 in the 2.8-km downwind residential regions near the MSW landfill. With the increase in PM concentration, higher-abundance microorganisms were detected. A number of cultivable bacterial species (Micrococcus endophyticus, Micrococcus flavus, Bacillus sporothermodurans, Salmonella entericaserovar typhi, Rhodococcus hoagie, Blastococcups) and fungal species (Aspergillus niger, Penicillium, Microascus cirrosus, Cochliobolus, Stemphylium vesicarium) were identified in these bioaerosols. Furthermore, distinguished by transmission electron microscopy, a longer-range transported microorganism (E. coli) clinging onto suspended PM was observed, signifying higher exposure risks. Human health risk assessments demonstrate that the residents and occupational workers in the vicinity of MSW landfill endured atmospheric diffusion-induced bioaerosol exposure risks due to open dumping activities in MSW landfill. This study clearly indicates bioaerosol pollution from landfills, and people particularly living nearby the MSW facilities, must decrease outdoor activities during dusty days.