Determination of minor elements in soil profiles by neutron activation analysis
| Autor: | L.C. Bate |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
business.product_category
Soil test Chemistry Health Toxicology and Mutagenesis Public Health Environmental and Occupational Health Trace element Mineralogy Weathering Pollution Humus Analytical Chemistry Plough Nuclear Energy and Engineering Soil water Soil horizon Radiology Nuclear Medicine and imaging Neutron activation analysis business Spectroscopy |
| Zdroj: | Journal of Radioanalytical Chemistry. 15:193-202 |
| ISSN: | 1588-2780 0134-0719 |
| DOI: | 10.1007/bf02516571 |
| Popis: | Soil samples are often used in an effort to place a suspect at a particular location, i. e., material from the suspect's shoes, clothes, car, etc. is compared with soil from the crime area. The trace element concentration in both samples has been used to establish identity; this has been obtained usually by use of neutron activation analysis. In rural areas and farms more than half a dozen different kinds of soil may be present, and each soil may consist of several horizons. Horizons in turn may be broken down into sub-horizons or transitional layers, depending upon the humus present and the amount of weathering. Thus it would appear that comparison of soil samples would require rather exhaustive knowledge of the terrain, depth, and history of the samples area since variations of the elements in the soil are affected by eluviation (washing out) or illuviation (washing in). Such variations are illustrated by showing the change of concentration of elements with soil depth. Even though most forensic applications require comparisons of only the top inch or two of soil, the samples must be classified as to depth and type of soil since man often change the soil profile (ploughing, construction, etc.), or nature does (rain, decay, etc.). We have collected a number of soil samples from a several square mile area in both the horizontal and vertical profile. These soils were dried, thoroughly mixed, and portions, irradiated for one minute (for short half-life induced activities), and one week (for long half-life activities) at a flux of ∼10 n·cm−2·sec−1. Standards were irradiated in the same manner as samples. A number of elements were determined non-destructively; chemical separation was performed to determine others. Our results indicate great variation (factors of two or more occur in the concentration of many trace elements in going from the surface to several inches below. Similar variations occur in the horizontal plane. These data ind ate that comparison of soil samples by use of trace element concentrations is subject to considerable uncertainty. If large variations can be found within a small sampling area, the statistical significance of apparent agreement between two samples appears highly questionable. |
| Databáze: | OpenAIRE |
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