Soil forensic analysis

Gel electrophoresis has been applied to soil DNA and RNA extracts using procedures similar to those used in DNA testing for forensic analysis. CE has also been applied to the analysis of ionic species extracted from soil. While these processes show promise for the elucidation of valuable information about soil, neither is used for common, routine soil analysis [12-14],... 

Soil for microbiological studies is normally collected from the plow depth (10-23 cm at Rothamsted, United Kingdom, but it may vary elsewhere) and 0-10 cm depth for grassland or forest soils. For forensic analysis the sample depth will be decided by the nature of the crime scene. However, maximum biological activity will be adjacent to a corpse and will decline with depth... 

Cengiz, S. (2005). Reply to letter to the editor SEM-EDS analysis and discrimination of forensic soil. Forensic Sci. Int. 155, 225. 

Pye, K. and Croft, D. (2007). Forensic analysis of soil and sediment traces by scanning electron microscopy and energy-dispersive x-ray analysis An experimental investigation. Forensic Sci. Int. 165, 52-63. 

Ruffell, A. and Wiltshire, P. (2004). Conjunctive use of quantitative and qualitative x-ray diffraction analysis of soils and rocks for forensic analysis. Forensic Sci. Int. 145, 13-23. 

Wanogho, S., Gettinby, G., Caddy, B., and Robertson, J. (1987a). Some factors affecting soil sieve analysis in forensic science 1 Dry sieving. Forensic Sci. Int. 33, 129-137. 

Nevertheless, the technical and scientific achievements of nuclear forensics analysis are impressive. The ability to locate and detect minute amounts of uranium in a single particle in a swipe samples that may contain copious amounts of dust and soil particles is quite amazing. The fact that this individual particle may be singled out and its morphology, elanental, and isotopic compositions determined is indicative of the progress of analytical techniques. 

The Munsell color system is conceptually similar to the QELAB system, but with some significant differences. The Munsell system was conceived by the American painter Albert H. MunseU in 1905 with subsequent revisions and variations. The three variables used to describe colors in the system are hue, brightness (similar to lightness in QELAB), and saturation (similar to chroma also called value). As shown in Figure 11.14, the color space is cylindrical. The hue is divided into 100 equal spaces around the circle that forms the cross section of the cylinder, while the y direction is the brightness, scaled from 0 to 18. The x-axis is the saturation, scaled from 10 to 18. Munsell charts and collections are used in the forensic analysis of paints and soils. Because books and samples of color are used for color comparison, the Munsell color space is sometimes referred to as a catalog system. An example application is in soil analysis in which soil particles can be seived, sorted, and grouped by their Munsell color. 

Since its inception in 1990, there have been nearly 1000 papers published in the literature employing SPME. Headspace SPME alone cam account for must of the increase in publications on headspace-related techniques since 1997. Among these papers, there are myriad applications. Supelco has produced an applications guide that lists about 500 of these (74). In general, applications of SPME are seen in environmental analysis, including air, soil, and water, food, natural products, pharmaceuticals, and clinical and forensic analysis, plus numerous articles on theoretical aspects. SPME has proved to be one of the most versatile sample preparation techniques available. 

The elements listed in the table of Figure 15.2 are of importance as environmental contaminants, and their analysis in soils, water, seawater, foodstuffs and for forensic purposes is performed routinely. For these reasons, methods have been sought to analyze samples of these elements quickly and easily without significant prepreparation. One way to unlock these elements from their compounds or salts, in which form they are usually found, is to reduce them to their volatile hydrides through the use of acid and sodium tetrahydroborate (sodium borohydride), as shown in Equation 15.1 for sodium arsenite. 

Qin BH, Yu BB, Zhang Y, Lin XC. Residual analysis of organochlorine pesticides in soil by gas chromatograph-electron capture detector (gc-ecd) and gas chromatograph-negative chemical ionization mass spectrometry (GC-NCI-MS). Environ. Forensics 2009 10 331-335. 

Samples for analysis can come from products of vegetable or animal origin (milk, meat), water, air (ashes emitted by an incinerator) or soils in which elements are present over a wide range of concentrations (from manure spreading on agricultural land to industrial sludge). This method also has applications in the area of forensic sciences and clinical medicine (tissue analysis or biological fluids). 

Soils can have characteristics due to human activity (anthropogenic soils). The forensic examination of soil is therefore not only concerned with the analysis of naturally occurring rocks, minerals, plant, and animal matter it also includes the detection of such manufactured materials as ions from synthetic fertilizers and from different environments (e.g., nitrate, phosphate, sulfate) and environmental artifacts (e.g., lead or objects such as glass, paint chips, asphalt, brick fragments, and cinders). Each of these materials can represent distinct soil characteristics. When unique particles are found in soil evidence, more precise and rapid discrimination can be achieved even if the amount of evidence recovered is microscopic (Sugita and Marumo 2004). For this reason, microscopy is often considered the most useful technique for the detection of such characteristic particles. 

The lead contents of 206 soil samples determined by AAS indicated that such determination provides a useful parameter for soil comparison and discrimination in forensic science (Chaperlin 1981). Soil investigations near a former smelter in Colorado revealed that historic use of arsenical pesticides has contributed significantly to anthropogenic background concentrations of arsenic on certain residential properties. A variety of forensic techniques including spatial analysis, arsenic speciation and calculation of metal ratios were successful in the separation of smelter impacts from pesticide impacts (Folkes, Kuehster, and Litle 2001). 

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