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The airborne fraction of soil (dust) is both ubiquitous in nature and contains localised biological and chemical signatures, making it a potential medium for forensic intelligence. Metabarcoding of dust can yield biological communities unique to the site of interest, similarly, geochemical analyses can uncover elements and minerals within dust that can be matched to a geographic location. Combining these analyses presents multiple lines of evidence as to the origin of dust collected from items of interest. In this work, we investigated whether bacterial and fungal communities in dust change through time and whether they are comparable to soil samples of the same site. We integrated dust metabarcoding into a framework amenable to forensic casework, (i.e., using calibrated log-likelihood ratios) to predict the origin of dust samples using models constructed from both dust samples and soil samples from the same site. Furthermore, we tested whether both metabarcoding and geochemical/mineralogical analyses could be conducted on a single swabbed sample, for situations where sampling is limited. We found both analyses could generate results from a single swabbed sample and found biological and chemical signatures unique to sites. However, we did find significant variation within sites, where this did not always correlate with time but was a random effect of sampling. This variation within sites was not greater than between sites and so did not influence site discrimination. When modelling bacterial and fungal diversity using calibrated log-likelihood ratios, we found samples were correctly predicted using dust 67% and 56% of the time and using soil 56% and 22% of the time for bacteria and fungi communities respectively. Incorrect predictions were related to within site variability, highlighting limitations to assigning dust provenance using metabarcoding of soil. • Biological and chemical properties of dust were assessed for provenance assignment potential. • Dust samples contained biological profiles that were variable within sites but different between sites. • Chemical and biological properties were recovered from a single swab, but chemical signals differed to reference samples. • A framework was developed to convert biological data to log-likelihood ratios for forensic casework. • Dust sample origin predictions were found to be influenced by within site variability and the choice of reference sample. [ABSTRACT FROM AUTHOR]

Multi-element near-surface geochemistry from the National Geochemical Survey of Australia has been evaluated in the context of mapping the exposed to deeply buried major crustal blocks of the Australian continent. The major crustal blocks, interpreted from geophysical and geological data, reflect distinct tectonic domains comprised of early Archean to recent Cenozoic igneous, metamorphic and sedimentary rock assemblages. The geochemical data have been treated as compositional data to uniquely describe and characterize the geochemistry of the regolith overlying the major crustal blocks across Australia according to the following workflow: imputation of missing/censored data, log-ratio transformation, multivariate statistical analysis, multivariate geospatial (minimum/maximum autocorrelation factor) analysis, and classification. Using cross validation techniques, the uniqueness of each major crustal block has been quantified. The ability to predict the membership of a surface regolith sample to one or more of the major crustal blocks is demonstrated. The predicted crustal block assignments define spatially coherent regions that coincide with the known crustal blocks. In some areas, inaccurate predictions are due to uncertainty in the initial crustal boundary definition or from surficial processes that mask the crustal block geochemical signature. In conclusion, the geochemical composition of the Australian surface regolith generally can be used to map the underlying crustal architecture, despite secondary modifications due to physical transport and chemical weathering effects. This methodology is however less effective where extensive and thick sedimentary basins such as the Eromanga and Eucla basins overlie crustal blocks. [ABSTRACT FROM AUTHOR]

Abstract: The Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) Otway Project in the onshore Otway Basin, Victoria, is Australia’s first pilot project for the long term sequestration of CO2. The Otway Project has injected 65,445 tonnes of a mixed CO2-CH4 supercritical fluid (77 mol% CO2, 20 mol% CH4, 3 mol% of minor wet gases and N2) some 2000 m below the surface into the Waarre Formation, which is capped by the Belfast Mudstone regional seal. The site has been comprehensively characterised by a multidisciplinary team and the risk analysis has shown the likelihood of leakage out of the injection horizon–let alone to the land surface–to be exceedingly low. Nevertheless, the objectives of the CO2CRC through the Otway Project are not only to demonstrate safe CO2 injection, but also to develop new methodologies for monitoring and verification (M&V) of carbon storage that might apply to future commercial scale injection. At Otway, this involves M&V at the reservoir level and Assurance Monitoring, in the shallow subsurface (aquifers and soils) and the atmosphere. The groundwater monitoring system represents the most comprehensive system for monitoring freshwater in the vicinity of a CO2 storage demonstration to date. Monitoring the groundwater is of particular significance in demonstrating the ongoing integrity of natural resources to the general community. The first benchmark of any monitoring system is the establishment of a baseline from which to define natural variations in the system prior to injection. At Otway the natural baseline is complex due to the influence of the Port Campbell Limestone immediately below the soil zone. Since June 2006, groundwater levels and composition have been monitored at 21 bores completed in the unconfined Port Campbell Limestone aquifer, and 3 bores completed in the deeper confined Dilwyn aquifer. All monitoring wells are located within 10 km of the CRC-1 injection well. The groundwater program includes (i) biannual geochemical sampling to establish groundwater composition; (ii) monitoring of water levels to determine seasonal variations to formation water flow rate and direction; and (iii) headspace gas sampling of the Dilwyn aquifer to detect tracer compounds and CO2 content. This monitoring is necessary to establish the connectivity and fluid migration timescales of the fresh water aquifers and to understand the water-rock interactions and resulting fluid composition. The assurance monitoring team works closely with government agencies and landowners and provides data as required. Community engagement has been vital to the success of the program and considerable effort goes toward keeping landowners informed of our activities and minimizing disruption to their properties. To date, the groundwater component of the assurance monitoring program has not detected any perturbation in the baseline condition as a consequence of CO2 injection. It is important to note that this does not necessarily indicate containment; it does however provide assurance to the community and regulators that the natural resources have not been impacted by the CCS activities and can continue to be used safely. [Copyright &y& Elsevier]

Levels and regional distribution of NO3 concentrations inrain, stream water, ground water and soil collected in eight small (12-30 km2) catchments, located in severely polluted (near Nikel/Zapoljarnij and Monchegorsk, Kola Peninsula, Russia) to nearly pristine (Northern Finland) parts of the European Arctic are discussed. Yearly atmospheric NOx emissions on the Kola Peninsula exceed 24,000 t. Still wet deposition of NO3-N is very lowcompared to Central Europe. The atmospheric NOx emissionshave no detectable regional influence on the NO3 level inrain. The NO3-N pool present in the soil profiles exceedsthe annual input from precipitation by a factor of 4-100. Variationsof the nitrate content in soil are higher within catchments than between catchments, indicating that NO3-concentrations in soil are rather governed by local site characteristics (water retention capacity and drainage conditions as some of the most important factors) than distance to major emitters. The nitrate concentration in stream and ground water is very low. The disruption of the bio-productiveprocesses and mineralization of plant debris and soil humus in the most damaged ecosystem result in a significant increase of NO3 concentrations in soils, stream and ground water. [ABSTRACT FROM AUTHOR]

Frozen topsoil samples (0--5 cm) were collected during March/April 1994 in eight Arctic catchments in northern Europe (four in Russia, three in Finland, one in Norway), at different distances and in different wind directions from the emissions of the Russian mining, roastingand smelting industry on the Kola Peninsula. Between 14 and 25 siteswere sampled in each of the eight catchments ranging in size from 12to 35 km{sup}2{end}. Results show that close to the smelters in Monchegorsk and Nikel, topsoil is clearly enriched in Ag, As, Bi, Cd, Co,Cr, Cu, Fe, Ni, Pb, Sb, Se, Te and V. Cu and Ni median contents in topsoils collected close to Monchegorsk are about 600 times higher than in the Finnish catchments. The effect of open-cast mining and wastedumps of alkaline rocks from the nephelinite industry near Kirovsk can be seen in the elevated contents of Al, Ba, K, La, Mn, Na, Sr, Ti,Y and Zn in topsoil collected in a nearby catchment. For many elements, however, variations observed in single catchments are as great asthe total regional variation. Several elements (e.g. Cd, Hg, Cu, Ni,Pb, S, Zn) show strong positive correlation between the organic content of the sample and the element content observed. Thus it is necessary to determine the organic content of the samples and correct the element levels when using depth-related soil samples (here, the 0--5 cm topsoil layer) for regional mapping. [ABSTRACT FROM AUTHOR]