Abstract The nature of forensic geoscience Forensic geoscience may be defined as a subdiscipline of geoscience that is concerned with the application of geological and wider environmental science information and methods to investigations which may come before a court of law. The scientific boundaries of forensic geoscience are not clearly defined, and there are significant overlaps with other, related subdisciplines such as forensic archaeology (Hunter et al. 1987), forensic anthropology, forensic botany ( Hall 2002 ; Horrocks & Walsh 1998 ), forensic engineering ( Shuirman & Slosson 1992 ) and even forensic medicine and forensic pathology ( Knight 1997 ; DiMaio & DiMaio 2001 ). Forensic geoscience is concerned with all aspects of earth materials, including rocks, sediments, soil, air and water, and with a wide range of natural phenomena and processes. Since modern sediments and soil also often contain objects and particles of human origin, man-made materials such as brick, concrete, ceramics, glass and various other industrial products and raw materials are also sometimes of interest. These may be of relatively modern origin or of archaeological importance (e.g. Henderson 2002 ). Forensic geology ( Murray & Tedrow 1975, 1992 ) may be regarded as a subset of forensic geoscience and is principally concerned with studies of rocks, sediments, minerals, soils and dusts. Environmental forensics ( Morrison 2000 ; Murphy & Morrison 2002 ), on the other hand, has somewhat wider scope than forensic geoscience, with much stronger links to disciplines such as chemical engineering, and with a greater concern with such issues as groundwater contamination and air pollution modelling. Forensic geoscience is by nature

Abstract Colour is a fundamental characteristic of many materials, including soils and sediments, and has been much used in geological, pedological and Quaternary science research. Traditionally, colour has been described qualitatively by visual comparison with standard charts, such as the Munsell Soil Color Charts or the Geological Society of America Rock Color Chart . Instrumental colour determination has been developed and used in industry for a variety of applications, including quality testing of paints, dyes and foodstuffs. In this paper, colour theory is outlined, and the Minolta® CM-2002® hand-held spectrophotometer is tested on geological samples to investigate reproducibility, discriminatory power, and accuracy in analysis. Standard methods for calibration, presentation and testing of a variety of (often small) samples have been developed. Examples are provided for the use of the method in forensic geoscience casework.

Abstract Particle size distribution is a fundamental property of any sediment or soil, and particle size determination can provide important clues to sediment provenance. For forensic work, the particle size distribution of sometimes very small samples requires precise determination using a rapid and reliable method with a high resolution. A protocol has been developed using a Coulter™ LS230 laser granulometer, which can analyse particles in the size range 0.04 μ–2000 μ. The technique is essentially non-destructive, permitting the recovery of critical samples, and has been demonstrated to have high precision for a range of soils, sediments and powders of interest in forensic investigations.

Abstract A database of coastal dune sediments in England and Wales has been developed with potential applications in forensic investigations. Coastal dunes are popular sites for criminal-related activities, including burial of drugs, weapons and murder victims. The coastal dunes and associated areas of windblown sand in England and Wales occupy an area of approximately 200 km 2 within 112 individual identified systems. Research has been undertaken to ascertain the spatial variation in sedimentological properties of the coastal dune sediments in England and Wales. Field sediment sampling has been undertaken at each dune system. More than 1500 sediment samples have been analysed by laser diffraction to determine particle size characteristics, and more than 500 have been analysed by inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine chemical composition. Two examples illustrate how the database has been used in criminal investigation.

Abstract Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) microanalysis are powerful techniques for forensic and wider environmental analysis of a range of materials, including rocks, sediments, soils and dusts. Methods of analysis have evolved rapidly over the past 40 years and computer-controlled, variable pressure SEMs with integrated EDX now provide the opportunity for rapid, automated analysis of large numbers of samples and particulates within individual samples. However, interpretation of the data requires care and experience on the part of the operator, and samples should always be checked by visual inspection. Early SEM work on rocks and sediments mainly used the secondary electron (SE) mode to produce topographical contrast on rough surfaces, but more recent studies have utilized the capacity of backscattered electron (BSE) imaging to image both topographical and atomic number contrast. BSE microscopy, combined with X-ray mapping, provides a rapid means of locating unusual particles and grain coatings, and of mapping their distribution, which may be of diagnostic or discriminatory importance. In the past, much attention has been given to grain surface textural features (mainly of quartz) but many such studies have suffered from a high degree of subjectivity, poor reproducibility, lack of discriminatory power, and high cost both in terms of time and money. The application of digital imaging and statistical data-processing techniques can to some extent reduce these problems but, in general, chemical characterization of particles offers a more powerful approach. This paper provides an overview of these techniques, discusses their limitations and illustrates some of the forensic and wider environmental applications.

Abstract Analysis of geochemical data has become an important tool used in forensic comparisons of soils and sediments. The combined use of inductively coupled plasma optical emission spectrometry and mass spectrometry (ICP-OES and ICP-MS) instrumentation allows the abundance of up to 50 elements to be routinely determined in small samples (typically >0.1g). However, key issues concern the extent to which analysed subsamples are representative of the parent material from which they are taken, the best means of comparing datasets for different samples, and interpretation of the significance of the results obtained. ICP measurement precision for most elements is good, but it is important to understand the degree of variation that can arise due to subsampling procedures and selective transfer mechanisms relating to forensic exhibits, as well as the extent of spatial (and sometimes temporal) variability which exists in nature. Although analysis of several different size fractions is often helpful where sufficiently large samples are available, analysis of a standardized <150μm fraction separated from a bulk sample in many cases provides adequate discrimination between samples and provides the most practical method for mass-screening of samples. Where possible, duplicate or triplicate sample preparations should be made, and several analytical determinations made on each prepared subsample. However, the additional time, cost and sample size requirements involved need to be weighed against the benefits of undertaking additional types of analysis of the samples. In order to obtain maximum information from multielement geochemical data, the dataset should be evaluated using a variety of numerical, statistical and graphical procedures. This paper discusses a number of options for such data evaluation using a simple dataset example. Casework experience and experiments have shown that, even in complex situations, multi-element geochemical data can provide very sensitive environmental indicators. However, such data should normally be used in combination with the results of other analyses when making forensic comparisons of soils and sediments.

Abstract Isotopic and elemental concentration data can be extremely useful in the identification of human remains. Archaeological, ecological and forensic investigations to date have primarily made use of 87 Sr/ 86 Sr, 143 Nd/ 144 Nd, 18 O/ 16 O and trace element data obtained from analysis of carbonate-hydroxyapatite in bones and teeth, and/or 12 C/ 13 C, 14 N/ 15 N, 18 O/ 16 O and 35 S/ 37 S ratios in bone collagen. However, a wide range of other chemical parameters are potentially useful for intersample comparison and environmental characterization, and increasing attention is being given to hair, nail and skin tissues, which provide dietary and environmental information over shorter time periods than bones and teeth. This paper reviews some of the principles which underlie such work and the current position with regard to modern forensic applications.

Abstract A study has been undertaken to assess the significance of carbon and nitrogen content and stable isotopic variation in soils in relation to their practical use as a tool in forensic soil investigations. It forms part of a wider study to assess a range of techniques in a forensic context. Carbon and nitrogen abundance and δ 13 C and δ 15 N values have been determined in soil samples from six locations, using continuous flow-isotopic ratio mass spectrometry, to quantify: (1) stability over short time periods up to 2 years, (2) variation over short-scale distances, and (3) variability during primary transfer and mixing. Over a 2-year time period, variation was found to be largest in the elemental abundance, with the isotopic ratios being more stable. Used in combination, stable isotope analysis can be diagnostic and useful for discriminating between sites. No statistically significant differences at the 95% confidence level (using analysis of variance, ANOVA) were found for one-stage primary transfer in three of the four soils tested; the fourth sediment from an estuarine environment did show statistically significant difference at the 95% confidence level.

Abstract There are many user interests on coasts and in estuaries, including economic activities (ports, harbours, navigation, fishing, mineral extraction), recreation (bathing, walking, sailing, fishing, birdwatching), flood defence, water quality, nature conservation, and conservation of the historical and archaeological heritage. Often these interests are conflicting, and managers frequently have to attempt a compromise or make hard decisions based on a prioritized course of action which reflects economic, political and legal constraints (see, for example, Barrett 1992 ; Kay & Alder 1999 ; Flemming 2000 ). Often the decisions are taken on the basis of inadequate background information and a poor understanding of the functioning of the invariably complex coastal system under consideration. In a world of increasingly rapid technological and economic development, sea-level rise, and possible global climate change, central tasks facing the coastal and estuarine manager are to predict and manage change, undertaken against a background of constantly moving goalposts. There is an urgent need for a much better framework of background environmental data and more effective and reliable management tools, founded on sound scientific understanding, which can provide the necessary guidance and basis for policy formulation. Although, these needs have been recognized, and some progress has been made in the past few years, an adequate suite of such tools and frameworks for environmental monitoring are still some way off.

Abstract The coastal dune system of the Aquitaine region, SW France, is the largest in Europe. At the present time the dunes are mostly stabilized by forest vegetation which is largely the product of dune stabilization schemes undertaken since the late 18th century. Much of the shoreline is currently eroding at rates of 1–2 ma −2 , which are likely to increase if predictions of accelerated sea-level rise and increased storminess are correct. The sources of the beach and dune are poorly understood, and need to be identified in order to assess the sand budgets and likely dynamic response of the dune systems to changes in environmental forcing factors. This paper presents the results of an investigation to characterize the beach and aeolian sand in the region, and to identify its origin. The dune sands were found to be texturally and compositionally similar to the Quaternary Sable de Landes which occurs landward of, and partially beneath, the coastal dune belt. The results suggest that marine, aeolian and local fluvial reworking of the Sable de Landes has provided the main source of coastal dune sand, although marine erosion of Pleistocene deposits exposed in the coastal cliffs of the Medoc has made a secondary contribution.

Abstract The factors which influence the morphology, drainage characteristics and erosion resistance of saltmarshes are of major interest from the standpoint of flood defence and habitat recreation. Sedimentological characteristics, including grain size distribution, mineral composition and pore fluid chemistry arc all highly important. Of particular importance in muddy marshes is the nature of the clay mineral assemblage and dissolved cations present in the pore fluids. In marshes which are deficient in detrital calcium carbonate, such as those in Essex, UK, sodium ions dominate the exchange sites on clays, leading to the formation of thick water films around the clay particles and slow rates of sediment consolidation. This, in turn, causes low erosion resistance and a tendency for the development of highly dissected marsh morphology. Calcium and magnesium-rich marsh sediments, on the other hand, allow these ions to replace sodium in exchange sites, leading to more rapid dewatering and consolidation. Erosion resistance is thereby enhanced and such marshes tend to be characterized by low drainage densities and a low ratio of bare mud to vegetated surface area. The possibilty of engineering the erosion resistance and morphology of marshes through chemical treatments requires further investigation.