Soil dust

Dislodgeable soil residue (DSR) studies are used to determine exposure of re-entry workers to soil surface residues. Soil surface residues are defined as test substance residue levels in <150-q.m soil particles (i.e. soil dust which can stick to a worker s skin, or can be inhaled). 

The large amount of S in the particles suggested that S02 gas molecules or small sulfur-containing particles condense on to the surface of soil dusts during their transportation from China. Figure 4.22 illustrates an elemental map for Si distribution in coarse particles within a total scanning area of 25 pm x 25 pm. The scale bar shows the peak count of characteristic X-rays by pixel of the scan area. 

Exposures Of Children. Estimates are available for intake by children through ingestion of contaminated soils, dust, paint chips (EPA 1989c), and breast milk (Wolff 1983). However, some of these estimates are not current or well understood. To better understand the sensitivity of the nursing infant to chemicals such as lead, epidemiological studies, chemical monitoring, and model development and application are needed (Byczkowski et al. 1994). The bioavailability of lead from soil or dust on the hand after mouthing activity needs to be modeled. 

Soil, dust, and paint Digestion of sample with hot acid evaporation of water redissolution in HN03 AAS 12 ng/g >80 Que Hee et al. 1985b... 

Mielke HW, Adams JL, Reagan PL, et al. 1989. Soil-dust lead and childhood lead exposure as a function of city size and community traffic flow The case for lead abatement in Minnesota. Environ Chem Health 9(Supp) 253-271. 

Ingestion, of soil, dust, food, and drinking water. 

Natural sources of airborne nickel include soil dust, sea salt, volcanoes, forest fires, and vegetation exudates and account for about 16% of the atmospheric nickel burden (Kasprzak 1987 WHO 1991 Chau and Kulikovsky-Cordeiro 1995). Human sources of atmospheric nickel — which account for about 84% of all atmospheric nickel — include emissions from nickel ore mining, smelting, and refining activities combustion of fossil fuels for heating, power, and motor vehicles ... 

Veranth JM, Kaser EG, Veranth MM, Koch M, Yost GS (2007) Cytokine responses of human lung cells (BEAS-2B) treated with micron-sized and nanoparticles of metal oxides compared to soil dusts. Part Fibre Toxicol 4(1) 2. 

When parathion was released in the atmosphere on a sunny day, it was rapidly converted to the photochemical paraoxon. The estimated photolytic half-life is 2 min (Woodrow et al., 1978). The reaction involving the oxidation of parathion to paraoxon is catalyzed in the presence of UV light, ozone, soil dust, or clay minerals (Spencer et al., 1980, 1980a). 

Spencer, W.F., Adams, J.D., Shoup, T.D., and Spear, R.C. Conversion of parathion to paraoxon on soil dusts and clay minerals as affected by ozone and UV light, J. Agric. Food Chem., 28(2) 366-371, 1980. 

Smolen JM, Stone AT (1998) Organophosphorous ester hydrolysis catalyzed by dissolved metals and metal containing surfaces. In PM Huang et al. (eds) Soil chemistry and ecosystem health. Soil Sci Soc Am Spec Publ 52 Madison, Wisconsin, pp 157-171 Spencer WF, Shoup TD, Spear RC (1980) Conversion of parathion to paraoxon on soil dusts and clay-minerals as affected by ozone and UV-Ught. J Agric Food Chem 28 366-371 Stevenson FJ (1982) Humus chemistry. Wiley, New York Stevenson FJ (1986) Cycles of soil. Wiley Interscience, New York... 

Consequently, soil samples from feedlots have a dual origin of toco-pherols. This is illustrated with the GC-MS data of a study done in the San Joaquin Valley of California (Fig. 5b, ). The y-tocopherol is derived exclusively from the vegetation fodder, while a-tocopherol is derived from both vegetation and the hydrolysis of the tocopheryl acetate feed supplement. Excess a-tocopherol acetate, not hydrolyzed in the animal gut, is also present. Because a-tocopherol acetate is relatively stable, its presence in soil dust samples indicates the level of its usage as a feed supplement. A significant metabolite of a-tocopherol elutes after the acetate and the... 

Particulate matter is the term used to describe solid particles and liquid droplets found in the atmosphere. Particulates are produced by a host of natural and anthropogenic sources. Mist and fog are both forms of natural particulates, as are windblown soil, dust, smoke from forest fires, and biological objects, such as bacteria, fungal spores, and pollen. The incomplete combustion of fossil fuels is one of the most important anthropogenic (human-made) sources of particulates. Such processes release unhurned carbon particles, oxides of sulfur and nitrogen, and a host of organic compounds into the air. 

Iron was chosen as the reference element because its major source is likely to be soil and it is measured with good accuracy and precision by FIXE. Crustal abundances were taken from Mason (21). Enrichment factors greater than 1 indicate an enrichment of that element relative to crustal abundances values less than 1 indicate a depletion. The results of this calculation are shown in Table 4. For this calculation it was assumed that ammonium and nitrate accounted for all aerosol nitrogen. It is seen that Si and Ca are near their crustal abundance, indicating a probable soil dust source. The low EF for Al is probably due to a systematic error in the Al measurement rather than a true depletion. Potassium, although present in small concentrations, is slightly enriched relative to crust. The other fine aerosol species, C, N, S, and Pb are enriched by factors of thousands over their natural crustal abundance, indicating that they are not due to wind-blown dust. 

Herring et al. (1996) have reported evidence for the heterogeneous oxidation of both S02 and NO. on the surfaces of soil dust particles in the smoke plume from the 1991 Kuwait oil fires. The rate of S02 oxidation was estimated to be 6.5% h l. 

Figure 9.35 shows a typical set of mass size distributions for total suspended particles (TSP), Na, Cl, Al, V, NO-, S04, and NH4 at Chichi in the Ogasawara (Bonin) Islands, about 1000 km southeast of the main island of Japan (Yoshizumi and Asakuno, 1986). As expected for a marine site such as this, Na and Cl from sea salt predominate, and both the TSP and Na and Cl components peak in the coarse particle range. Al is also found primarily in the larger particles and is attributed to a contribution from soil dust. On the other hand, vanadium, non-sea salt sulfate (nss-S04 ), and ammonium are primarily in the fine particles. The vanadium levels are extremely low and likely reflect long-range transport of an air mass containing the products of combustion of fuel oil, which contains V because it is likely associated with a combustion source, it would be expected in the fine particle mode, consistent with Fig. 9.35. 

Duce, R. A., C. K. Unni, B. J. Ray, J. M. Prospero, and J. T. Merrill, Long-Range Atmospheric Transport of Soil Dust from Asia to the Tropical North Pacific Temporal Variability, Science, 209, 1522-1524 (1980). 

Prospero, J. M., R. A. Glaccuni, and R. T. Nees, Atmospheric Transport of Soil Dust from Africa to South America, Nature, 289, 570-572 (1981). 

However, this is not the case for airborne particles composed of crustal materials formed by erosion processes. As discussed in Chapter 9.C, mineral dust consists primarily of such crustal materials. Despite the fact that soil dust particles tend to be quite large, of the order of a micron and larger, they can be carried large distances. These particles not only scatter and absorb solar radiation but also absorb long-wavelength infrared emitted by the earth s surface. 

Table 1 lists a number of studies carried out in urban sites of the Eastern Mediterranean Basin that have used multivariate statistical methods to quantify the mass contribution of sources of particulate matter. In most of these studies, four or five major source categories have been detected. These categories include road/soil dust, traffic emissions, marine aerosol, fuel oil combustion emissions, biomass... 

Site/PM fraction, study soil dust Traffic Fuel oil burning aerosol unidentified... 

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