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Soil trace evidence can be useful in criminal investigations. A homicide which had occurred in South Brazil been concluded through the courts with a guilty conviction. A spade with soil traces adhering to it was seized from the confessed killer's house, it having been established that it had been used to bury parts of the victim's body. In the context of this confession, it provided an opportunity to test a protocol of analysis and verify the potential of discriminate soil sample analysis in such case works. This allowed us to test the practice of sequential analysis which had been developed for forensic case works in Brazil, with three sequential extractions: (i) 0.2 mol/L pH 3.0 ammonium oxalate; (ii) dithionite-citrate-bicarbonate; and (iii) 0.5 mol/L NaOH. It was possible to predict the sequence of events related to the homicide by using the sequential extraction technique and to conclude that: (i) the A horizon soil from the burial location of the torso was found to be very similar to the soil samples which had been recovered from the spade, which was able to be established despite there only being a small amount of soil adhering to the spade; (ii) the location where the legs were buried contributed a low amount of soil adhering to the spade. Therefore, it is suggested that, where possible, sequential extractions should be prioritized from a questioned sample to best provide information about the likely sequence of contact places and this test likely scenarios and criminal events.

In July 2013 the International School Science Fair (ISSF) was hosted by Camborne Science and International Academy, Cornwall, UK. This meeting brings young talented scientists together from around the world to participate in workshops and activities highlighting current scientific developments. As part of ISSF 2013, a workshop on forensic geology was delivered to some of the international participants. This included the preparation of a map to show the mineralogical composition of the soils of the participating schools. The soil mineralogy was determined using automated mineral analysis based on scanning electron microscopy. In addition there were workshops on the recovery of geological trace evidence in a forensic context and the theory and practice of carrying out a geophysical search for hidden items. Data generated as part of this workshop are available to download from the International Union of Geological Sciences, Initiative on Forensic Geology website (http://www.forensicgeologyinternational.com).

The use of chemical enhancement techniques on porous substrates, such as fabrics, poses several challenges predominantly due to the occurrence of background staining and diffusion as well as visualization difficulties. A range of readily available chemical and lighting techniques were utilized to enhance footwear impressions made in blood, soil, and urine on dark and patterned fabrics. Footwear impressions were all prepared at a set force using a specifically built footwear rig. In most cases, results demonstrated that fluorescent chemical techniques were required for visualization as nonfluorescent techniques provided little or no contrast with the background. Occasionally, this contrast was improved by oblique lighting. Successful results were obtained for the enhancement of footwear impressions in blood; however, the enhancement of footwear impressions in urine and soil on dark and patterned fabrics was much more limited. The results demonstrate that visualization and fluorescent enhancement on porous substrates such as fabrics is possible.

Soils may constitute evidence that connects a person or object to a particular location. The value of soil stems from its ubiquity and transferability to objects or persons. Due to the complexity of soil, the analysis of its inorganic and organic components can provide complementary and independent types of information about its geological origin, dominant vegetation, management and environment. We present an overview of a range of soil characterisation methods including chemical analysis, mineralogy and palynology, along with new approaches such as DNA profiling and profiling of other digital data such as that obtained from X-ray powder diffraction, infrared spectroscopy and organic marker analysis. Individual analytical techniques have different scales of resolution and relevance depending on the nature of the criminal case and context. Each method has its strengths and weaknesses. As more methods have become digital and quantitative, their use in combination as digital profiles will help to characterise soils more accurately and at different scales. These new approaches can be tested using existing soil databases, and database development and use will help to refine and narrow probable origin of a questioned sample in police intelligence, as well as giving increasingly robust sample comparisons for evidence. Copyright © 2010 John Wiley & Sons, Ltd.

The effects of 4 years of simulated nitrogen deposition, as nitrate (NO3 ) and ammonium (NH4 1), on microbial carbon turnover were studied in an ombrotrophic peatland. We investigated the mineralization of simple forms of carbon using MicroRespt measurements (a multiple substrate induced respiration technique) and the activities of four soil enzymes involved in the decomposition of more complex forms of carbon or in nutrient acquisition: Nacetyl- glucosaminidase (NAG), cellobiohydrolase (CBH), acid phosphatase (AP), and phenol oxidase (PO). The potential mineralization of labile forms of carbon was significantly enhanced at the higher N additions, especially with NH4 1 amendments, while potential enzyme activities involved in breakdown of more complex forms of carbon or nutrient acquisition decreased slightly (NAG and CBH) or remained unchanged (AP and PO) with N amendments. This study also showed the importance of distinguishing between NO3 and NH4 1 amendments, as their impact often differed. It is possible that the limited response on potential extracellular enzyme activity is due to other factors, such as limited exposure to the added N in the deeper soil or continued suboptimal functioning of the enzymes due to the low pH, possibly via the inhibitory effect of low phenol oxidase activity.

International audience; Understanding of plant interactions is greatly limited by our ability to identify and quantify roots belonging to different species. We proposed and compared two methods for estimating the root biomass proportion of each species in artificial mixtures: near-infrared reflectance spectroscopy (NIRS) and plant wax markers. Two sets of artificial root mixtures composed of two or three herbaceous species were prepared. The proportion of root material of each species in mixtures was estimated from NIRS spectral data (i) and the concentration patterns of n-alkanes (ii), n-alcohols (iii), and n-alkanes +n-alcohols combined (iv). For each data set, calibration equations were developed using multivariate statistical models. The botanical composition of root mixtures was predicted well for all the species considered. The accuracy varied slightly among methods: alkanes < alcohols = alkanes + alcohols < NIRS. Correlation coefficients between predicted and actual root proportions ranged from 0.89 to 0.99 for alkanes + alcohols predictions and from 0.97 to 0.99 for NIRS predictions. These two methods provide promising potential for understanding allocation patterns and competitive interactions.

Grasslands can be a complex mixture of plant species. A method is described to allow the identification of both roots and shoots of five different grass species, thus permitting greater knowledge about whole plant allocation and competition in mixed pastures. The five species were Lolium perenne, Festuca ovina, Festuca rubra, Poa trivialis and Agrostis capillaris. N-alkanes with odd-numbers of carbon atoms in the chains predominate in plants and in the five grass species studied, concentrations of alkanes of chain length of C29, C31 and C33 were highest. Average concentrations of C27-C33 alkanes in shoots and roots were 187 and 11 mg kg−1, respectively. This wide range of values required considerable modifications to the method of analysis, including expressing concentrations on an organic matter basis and scaling-down the procedure. The n-alkane concentrations in roots are different from those in shoots and therefore values from shoots cannot be used to predict the composition in roots. Using a canonical variate analysis, all five grass species could be separated using concentrations of C26, C31 and C33 values in the roots. The greatest difference occurred between A. capillaris and the others, whereas discrimination was least between the two Festuca species. Defoliation had contrasting effects on the concentration of a few n-alkanes, but not in the n-alkanes used to discriminate between grass species. Alkane analysis shows great potential as a method to quantify the species composition of the root biomass beneath mixed pasture species.