Quantitative Microbial Risk Assessment in Occupational Settings Applied to the Airborne Human Adenovirus Infection.

Annalaura Carducci,Gabriele Donzelli,Lorenzo Cioni,Marco Verani

doi:10.3390/ijerph13070733

Abstract

Quantitative Microbial Risk Assessment (QMRA) methodology, which has already been applied to drinking water and food safety, may also be applied to risk assessment and management at the workplace. The present study developed a preliminary QMRA model to assess microbial risk that is associated with inhaling bioaerosols that are contaminated with human adenovirus (HAdV). This model has been applied to air contamination data from different occupational settings, including wastewater systems, solid waste landfills, and toilets in healthcare settings and offices, with different exposure times. Virological monitoring showed the presence of HAdVs in all the evaluated settings, thus confirming that HAdV is widespread, but with different average concentrations of the virus. The QMRA results, based on these concentrations, showed that toilets had the highest probability of viral infection, followed by wastewater treatment plants and municipal solid waste landfills. Our QMRA approach in occupational settings is novel, and certain caveats should be considered. Nonetheless, we believe it is worthy of further discussions and investigations.

Highlights

Occupational biological risk assessment is difficult because of the wide range of pathogenic agents, different types of exposure, the stochastic nature of infections, the presence of workers with different levels of susceptibility to risk, and the lack of epidemiological data that would permit the establishment of certain limits of exposure
During a monitoring aimed to evidence the airborne contamination of 20 wastewater treatment plants, twenty-five samples were collected in areas that are at greatest risk of bioaerosol production: (i) entrance sewage as entry point of wastewater treatment plant; (ii) sludge treatment systems; (iii) biological oxidation tank; and (iv) side-entrance manhole
Exposure limits are not given for either infectious or non-infectious biological agents, agents, implying that the potential presence of a pathogen in the air should require implying that the potential presence of a pathogen in the air should require the usethe of use of respiratory personal protection equipment regardless of exposure time

Summary

Introduction

Occupational biological risk assessment is difficult because of the wide range of pathogenic agents, different types of exposure, the stochastic nature of infections, the presence of workers with different levels of susceptibility to risk, and the lack of epidemiological data that would permit the establishment of certain limits of exposure. Biological agents can pose serious risks in many work settings, mainly when they are transmitted through bioaerosols, defined as airborne particles with a biological origin [1]. Health effects that are caused by exposure to bioaerosols and can severely impact public health include infectious diseases, acute toxic effects, allergies, and cancer. Despite recognizing the importance of bioaerosol exposure with regard to human health, the assessment of occupational biological risk is generally limited to evaluating “potential exposure”, without any quantitative estimate. This evaluation is based on the concept that biological risk is stochastic even a single microbial infectious particle can theoretically cause infection in an

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