1a.Objectives (from AD-416)
Enumeration and characterization of the types/amounts of microbial bioaerosols, viable and gram-negative lipopolysaccharides, emitted during land application of anaerobically produced Class B biosolids at a field research site in North Carolina. Volatile organic compounds producing malodors and particulate matter (PM10) will also be collected and analyzed (chemically, molecularly, and biologically). Measurements of concurrent atmospheric conditions will be used to calculate emissions and transport downwind of any emitted aerosols.

1b.Approach (from AD-416)
Air samples will be collected using an array of 9 stationary and 1 mobile platform equipped with three different types of bioaerosol samplers. The samplers will be operated simultaneously for specific periods of time prior to, and during land application of biosolids. Samples of the air and solids being applied will be analyzed for a suite of bacterial groups, fungi, enteric viruses, and endotoxin, simultaneously with odorous volatiles collection and analysis from the field to which the biosolids were applied.

3.Progress Report
This report documents research conducted under a Reimbursable Agreement between ARS and the U.S. Environmental Protection Agency. Additional details of the research can be found in the report for the parent project 1265-32420-004-00D "Microbial Ecology & Safety of Fresh on-farm Organically Grown Produce." This project addresses concerns about the potential for drift and impacts on fresh produce from adjacent land application operations involving manure and treated sewage sludge. Both the dairy manure and sewage sludge used in the tests performed in the studies that were conducted involved treatments that are designed to reduce the content of pathogens. During the past year, data from three types of microbial air-sampling equipment and multiple land application tests were analyzed. Baseline upwind and downwind tests at increasingly farther distances from the source were obtained during biosolids application at the North Carolina Piedmont Experiment Station; and similar types of measurements were obtained during liquid manure spray application to fields in Beltsville, Maryland. Pathogens and nonpathogenic microbes were detected in the land applied solids. Nonpathogenic bacteria, but no pathogenic bacteria, were detected in lagooned dairy manure liquids that had been separated from the manure slurry liquids collected at the Beltsville Agricultural Research Center dairy barn scrap system. No pathogenic microbes were recovered from any air samples within the 20-100 ft downwind area prior to or during treated manure liquids or treated sewage sludge biosolids land application. For the biosolids, standard side-discharge equipment used for the land application of anaerobically digested solids, flung small clumps of material in a high arch pathway up to 40 ft away from the side-discharge chute onto the pasture surface. For the manure liquids, the spray applicator equipment nozzle was positioned about 10 ft above the soil surface. This created an extensive spray field about 40 ft wide and 20 ft deep from the nozzle source. This large spray field was subject to sudden wind gusts and generated spray drift. Background bioaerosol measurements conincided with vehicular movement without manure or biosolids. These operations generated their own airborne particulates that contributed to the bioaerosols collected and detected. Source strengths of microbial aerosols from biosolids were moderately concentrated for total heterotrophs on the mobile samplers that were continuously located 20 feet downwind of application equipment. Volatiles were measured in collaboration with the AMBL,ARS, Beltsville. Dimethyl disulfide, an intense and pervasive odorant, was not readily detected in aerobic biosolids, as it was in readily lagooned dairy manure liquids. Additional identifications of heterotrophic microbes (approximately 1300 individual isolates) were performed by fatty-acid methyl ester analysis. Data on bioaerosol enumerations and particulate size distributions of microbial particles was analyzed with assistance from the Biostatistical Support Services Unit. Results were reported to U.S.EPA and are being used used to prepare manuscripts for peer-review publications.