Introduction
This investigation analyzed the soil samples from the suspects clothing sample A, the spade sample B and badger sample C to determine any relationship between them. Analytical machines examined all three samples for the three specific aspects of mineralogy/clay, trace element concentration and physical properties.
Method
The three machines used to determine the three specific aspects of the three soil samples are the ICP-MS, SEM and XRD.
The ICP-MS detects the concentration of trace metals in soil samples in solution form that generally have an abundance of <0.1% with a concentration of pp. It can detect up to 50 elements at one time.
The SEM provides images of the soil samples at three different magnifications (x25.x500, x100) allowing assessment of the different physical properties including grain size, roundness, sorting of the grains and the texture of the grains. The SEM uses secondary electrons the soil to produce 3D images for interpretation.
The XRD determines mineral composition and clay type measuring the average spacing between layers and rows of atoms, and the orientation of a single crystal or grain along with the structure of an unknown material. This machine measures the size, shape and internal stress of small crystalline regions.
Analysis
Results produced by the SEM showed sample A and sample B had traits similar not common to l sample C. The grain in A and B had a similar trend in their sphericity, roundness and grain size, not present in the grains of sample C.
ICP-MS data made it possible to assess trace element concentration in the samples. After estimating error bars of each individual element on two histograms A vs. C and B vs. C, it was obvious that a few elements had concentrations that fell within the same error ranges of their counterpart element in the compared sample. In hectograph sample A vs. C, six elements, Mg, Al, K, Ni, Pb and U had very similar concentrations. In histogram sample B vs. C there were the elements Al, Fe and As.
Results from the XRD analysis showed the mineralogy and clay type found in the samples. For the clay types, sample A and C contained smectite, sample B contained Chlorite. The minerals present varied; soil sample A contained Celestine and sample B and C contained quartz.
Summary:
The SEM analysis showed samples A and B but not C may have the same source. Because SEM images are only subject to visual analysis, the ICP-MS and XRD provided further analysis.
The ICP-MS soil analysis showed concentrations of trace elements present in A vs. C and B vs. C. The common trace element aluminum shared the same error range and concentration levels in all three samples
The XRD revealed the types of mineral and clays found in the samples. The results showed that clay wise, sample A could have been from the badger set C, because of the common clay, smectite. The mineralogy results indicated sample B could be from C the common mineral here being Quartz.
Conclusion
The ICP-MS showed a few elements had concentrations that fell within the same error ranges of their counterpart element in the compared sample with similar concentrations of aluminum in all three. Both sample A and C contained smectite. Quartz was a common mineral in samples B and C; this opens the possibility that the soils from suspects and clothes could have contaminated with soil from the badger.
