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Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/2/2003 Publication Date: 9/1/2003 Citation: MILLER, D.N., WOODBURY, B.L. SIMPLE PROTOCOLS TO DETERMINE DUST POTENTIALS FROM CATTLE FEEDLOT SOIL AND SURFACE SAMPLES. JOURNAL OF ENVIRONMENTAL QUALITY. 2003. v. 32. p. 1634-1640. Interpretive Summary: A protocol was developed to measure the relative dust potential from various feedlot soils and manures. Results obtained using this protocol were very reproducible when standardized for sample volume, blending time, and dust collection time. Sample moisture and organic matter content had the greatest effect on dust potential; dust potential was very high below a defined moisture threshold, which was related to organic matter content. Application of the protocol to feedlot samples collected from different areas of the feedlot pen indicated that dust emission from the feedlot will likely vary from site to site even within the same feed pen. Measured dust potential using the dust generator is a relative value and not suitable for predicting the actual dust emission. The utility of the dust generator technique is its ability to compare samples (i.e., within pen, between feedlot, etc.) and predict whether dust emissions are possible and to assess the relative effect of certain treatments or dust control strategies on dust production. Technical Abstract: Cattle feedlot dust is an annoyance and may be a route for nutrient transport, odors, and pathogen dispersion, but important environmental factors that contribute to dust emissions are poorly characterized. A simple protocol was devised to test feedlot samples for the ability to produce dust and to compare the relative effects of treatments on dust potential. A blender was modified to produce dust and collect airborne particulates on glass fiber filters by vacuum collection. This system was tested with a variety of dried feedlot samples. A blending protocol optimized for sample volume (150 cm3), blending time (5 min preblending), and dust collection time (15 s) provided consistent dust measurements for all samples tested. The procedure was limited to low-moisture (20 to 40% by weight) samples, but performed well on samples that varied in organic matter content. When applied to field samples, the technique demonstrated considerable spatial variability between feedlot pen sites. Mechanistically, dust potential was related to moisture and organic matter content. Measured dust potential was not intended, nor is it suitable, for predicting the actual dust emissions from agricultural sources. Rather, dust potential was a useful measure to compare samples of differing composition and to investigate whether dust emissions could occur under various environmental parameters and their relative emission potential. |
