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Evaluation Of Airborne Endotoxin Concentrations Associated With Management Of Crop Grown On Applied Biosolids
Citation:
BARTH, E. F., R. F. HERRMANN, T. DAHLING, R. C. BRENNER, S. WRIGHT, AND P. CLARKE. Evaluation Of Airborne Endotoxin Concentrations Associated With Management Of Crop Grown On Applied Biosolids. P. Brent Duncan (ed.), JOURNAL OF RESIDUALS SCIENCE AND TECHNOLOGY. DEStech Publications, Inc, Lancaster, PA, 6(2):61-65, (2009).
Impact/Purpose:
To determine if a statistically significant difference existed between the mean upwind and mean downwind airborne concentrations of endotoxin, during grass raking and bailing activities among and within two proximal hayfields (grass), with one of the sites having been previously treated with biosolids as a soil amendment.
Description:
Public health concerns have been expressed regarding inhalation exposure associated with the application of biosolids on cropland, which is due to the potential aerosolization of microorganisms, cell wall products, volatile chemicals, and nuisance odors. Endotoxin is a component of the cell walls of Gram-negative bacteria and is likely present in many biosolids. The application of biosolids to cropland may result in an immediate exposure or a delayed exposure to these microbial agents, such as when the crops are harvested. Upwind and downwind airborne concentrations of endotoxin were compared among and within two adjacent established hayfields, one with and one without previously applied biosolids, during grass raking and bailing activities. The mean downwind concentration of airborne endotoxin was significantly higher than the mean upwind concentration at the site where biosolids had been previously applied. The mean downwind concentration of endotoxin was not significantly different than the mean upwind concentration at the control field where biosolids had not previously been applied. When comparing the mean concentrations of airborne endotoxin among the sites, significant main effects were noticed for wind direction and field type, and an interactive effect was noticed for direction and field type. It is not known if the increased mean concentration of endotoxin associated with the downwind air samples at the applied biosolids field were due to the residual biosolids that were previously applied or due to endotoxin associated with plant material. The results apply to this investigation only since there was no treatment replication of each type of field. The downwind endotoxin concentrations observed during the raking and bailing activities were lower than various health effects criteria that have been recommended for airborne endotoxin.
