|GERBA, CHARLES - University Of Arizona|
|PEPPER, IAN - University Of Arizona|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/2/2010
Publication Date: 10/2/2010
Citation: Brooks, J.P., Gerba, C.P., Pepper, I.L. 2010. Evaluating microbiological risks of biosolids land application (abstract). Workshop Proceedings Controlling Pathogens and Meeting Regulatory Requirements for Land Application of Biosolids, Waste Environment Federation Technical Exhibition and Conference, October 2-3, 2010, New Orleans, LA. Paper #209. CD-ROM.
Technical Abstract: The transmission of pathogens by land application of untreated human and animal wastes has been known for more than 100 years. The QMRA (quantitative microbial risk assessment) process involves four basic steps: pathogen identification, exposure assessment, dose-response and risk characterization. Several examples which were evaluated included: risk to workers, consumption of produce crops, consumption of produce crops following runoff contamination, aerosol exposure, and a picaphagic child. While some of these exposures are less likely for biosolids applications because of site and application restrictions, they can commonly occur in areas where manure is applied. Generally, one-time risks of infection were low bacteria with viruses (biosolids) increasing the chance of infection. Risks resulting from exposures to Campylobacter were relatively high in manure, while viruses were relatively high in biosolids for exposures resulting from occupational or pica exposures. Using more appropriate conditions of pathogen die-off in the soil (> 4 months), land application of either residual resulted in risks less than 1:10,000 per year. Assuming USDA-AMS and USEPA recommended guidelines and regulations are followed for crops grown on waste-applied land, risks associated with manure or biosolids land application are well below the 1:10,000 per year risk of infection standard. This analysis provides insight on the relative risks of animal waste and biosolid land application that allows for a better understanding of the risks to the general public and the industry.