Aims: The purpose of this study was to evaluate the community risk of infection from bioaerosols to residents living near biosolids land application sites. Methods and Results: Approximately 350 aerosol samples from 10 sites located throughout the USA were collected via the use of six SKC BiosamplersÒ. Downwind aerosol samples from biosolids loading, unloading, land application and background operations were collected from all sites. All samples were analysed for the presence of HPC bacteria, total coliform bacteria, Escherichia coli, Clostridium perfringens, coliphage, enteroviruses, hepatitis A virus and norovirus. Total coliforms, E. coli, C. perfringens and coliphage were not detected with great frequency from any sites, however, biosolids loading operations resulted in the largest concentrations of these aerosolized microbial indicators. Microbial risk analyses were conducted on loading and land application operations and their subsequent residential exposures determined. Conclusions: The greatest annual risks of infection occurred during loading operations, and resulted in a 4 · 10 )4 chance of infection from inhalation of coxsackievirus A21. Land application of biosolids resulted in risks that were <2 · 10 )4 from inhalation of coxsackievirus A21. Overall bioaerosol exposure from biosolids operations poses little community risk based on this study. Significance and Impact of the Study: This study evaluated the overall incidence of aerosolized microorganisms from the land application of biosolids and subsequently determined that microbial risks of infection were low for residents close to biosolids application sites.

Aim: The purpose of this study was to develop an empirically derived transport model, which could be used to predict downwind concentrations of viruses and bacteria during land application of liquid biosolids and subsequently assess microbial risk associated with this practice. Methods and Results: To develop the model, coliphage MS-2 and Escherichia coli were aerosolized after addition to water within a biosolids spray application truck, and bioaerosols were collected at discrete downwind distances ranging from 2 to 70 m. Although coliphage were routinely detected, E. coli did not frequently survive aerosolization. Data on aerosolized coliphage was then used to generate a virus transport model. Risks of infection were calculated for various ranges of human virus concentrations that could be found in biosolids. Conclusions: A conservative estimate at 30AE5 m (assumed to be nearest adjacent residences) downwind, resulted in risks of infection of 1 : 100 000, to the more realistic 1 : 10 000 000 per exposure. Conservative annual risks were calculated to be no more than 7 : 100 000 where as a more realistic risk was no greater than 7 : 10 000 000. Overall, the viral risk to residences adjacent to land application sites appears to be low, both for one time and annual probabilities of infection. Significance and Impact of the Study: This study demonstrated a simple approach towards modelling viral pathogens aerosolized from land applied liquid biosolids, and offers insight into the associated viral risk.

This study evaluated the use of pulsed-xenon ultraviolet (PX-UV) room disinfection by sampling frequently touched surfaces in vancomycin-resistant enterococci (VRE) isolation rooms. The PX-UV system showed a statistically significant reduction in microbial load and eliminated VRE on sampled surfaces when using a 12-minute multiposition treatment cycle.

Some speculate that bioaerosols from land application of biosolids pose occupational risks, but few studies have assessed aerosolization of microorganisms from biosolids or estimated occupational risks of infection. This study investigated levels of microorganisms in air immediately downwind of land application operations and estimated occupational risks from aerosolized microorganisms. In all, more than 300 air samples were collected downwind of biosolids application sites at various locations within the United States. Coliform bacteria, coliphages, and heterotrophic plate count (HPC) bacteria were enumerated from air and biosolids at each site. Concentrations of coliforms relative to Salmonella and concentrations of coliphage relative to enteroviruses in biosolids were used, in conjunction with levels of coliforms and coliphages measured in air during this study, to estimate exposure to Salmonella and enteroviruses in air. The HPC bacteria were ubiquitous in air near land application sites whether or not biosolids were being applied, and concentrations were positively correlated to windspeed. Coliform bacteria were detected only when biosolids were being applied to land or loaded into land applicators. Coliphages were detected in few air samples, and only when biosolids were being loaded into land applicators. In general, environmental parameters had little impact on concentrations of microorganisms in air immediately downwind of land application. The method of land application was most correlated to aerosolization. From this large body of data, the occupational risk of infection from bioaerosols was estimated to be 0.78 to 2.1%/yr. Extraordinary exposure scenarios carried an estimated annual risk of infection of up to 34%, with viruses posing the greatest threat. Risks from aerosolized microorganisms at biosolids land application sites appear to be lower than those at wastewater treatment plants, based on previously reported literature.

The doffing of personal protective equipment (PPE) after contamination with pathogens such as Ebola poses a risk to health care workers. Pulsed xenon ultraviolet (PX-UV) disinfection has been used to disinfect surfaces in hospital settings. This study examined the impact of PX-UV disinfection on an Ebola surrogate virus on glass carriers and PPE material to examine the potential benefits of using PX-UV to decontaminate PPE while worn, thereby reducing the pathogen load prior to doffing. Ultraviolet (UV) safety and coverage tests were also conducted. PX-UV exposure resulted in a significant reduction in viral load on glass carriers and PPE materials. Occupational Safety and Health Administration-defined UV exposure limits were not exceeded during PPE disinfection. Predoffing disinfection with PX-UV has potential as an additive measure to the doffing practice guidelines. The PX-UV disinfection should not be considered sterilization; all PPE should still be considered contaminated and doffed and disposed of according to established protocols.