Chemical Constituents of Fugitive Dust |
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Authors: | R Scott Van Pelt Ted M Zobeck |
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Institution: | (1) Wind Erosion and Water Conservation Research Unit, USDA, Agricultural Research Service, 302 W. I-20, Big Spring, TX 79720, USA;(2) Wind Erosion and Water Conservation Research Unit, USDA, Agricultural Research Service, 3810 4th St., Lubbock, TX 79415, USA |
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Abstract: | Wind erosion selectively winnows the fine, most chemically concentrated portions of surface soils and results in the inter-regional
transport of fugitive dust containing plant nutrients, trace elements and other soil-borne contaminants. We sampled and analyzed
surface soils, sediments in transport over eroding fields, and attic dust from a small area of the Southern High Plains of
Texas to characterize the physical nature and chemical constituents of these materials and to investigate techniques that
would allow relatively rapid, low cost techniques for estimating the chemical constituents of fugitive dust from an eroding
field. From chemical analyses of actively eroding sediments, it would appear that Ca is the only chemical species that is
enriched more than others during the process of fugitive dust production. We found surface soil sieved to produce a sub-sample
with particle diameters in the range of 53–74 μm to be a reasonably good surrogate for fugitive dust very near the source
field, that sieved sub-samples with particle diameters <10 μm have a crustal enrichment factor of approximately 6, and that
this factor, multiplied by the chemical contents of source soils, may be a reasonable estimator of fugitive PM10 chemistry from the soils of interest. We also found that dust from tractor air cleaners provided a good surrogate for dust
entrained by tillage and harvesting operations if the chemical species resulting from engine wear and exhaust were removed
from the data set or scaled back to the average of enrichment factors noted for chemical species with no known anthropogenic
sources. Chemical analyses of dust samples collected from attics approximately 4 km from the nearest source fields indicated
that anthropogenic sources of several environmentally important nutrient and trace element species are much larger contributors,
by up to nearly two orders of magnitude, to atmospheric loading and subsequent deposition than fugitive dust from eroding
soils. |
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Keywords: | Dust chemistry Fugitive dust Nutrient transport PM10 Trace element transport |
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