The Key Factors for the Fate and Transport of Petroleum Hydrocarbons in Soil With Related in/ex Situ Measurement Methods: An Overview

Once petroleum hydrocarbons (PHs) are released into the soil, the interaction between PHs and soil media is dependent not only upon the soil properties but also on the characteristics of PHs. In this study, the key factors influencing the interactions between PHs and soil media are discussed. The key factors include: 1) the characteristics of PHs, such as volatility and viscosity; and 2) soil properties, such as porosity, hydraulic properties and water status, and organic matter; and 3) atmospheric circumstances, such as humidity and temperature. These key factors can be measured either ex-situ using conventional laboratory methods, or in situ using portable or handheld instruments. This study overviews the current ex/in situ techniques for measuring the listed key factors for PH contaminated site assessments. It is a tendency to apply in situ methods for PH contaminated site characterisation. Furthermore, handheld/portable Fourier transform infrared spectroscopy (FTIR) instrument provides tremendous opportunities for in-field PH contaminated site assessment. This study also reviewed the non-destructive FTIR spectroscopy analysis coupling with handheld FTIR for in-field PH contaminated site characterisation, including determining the concentration of total PH, dominant PH fractions and soil key properties for PH transport modelling.

Rapid In-Field Approaches for Delineating VOC in Both Soil Vapour and Groundwater for Vapour Intrusion Assessment

Traditional contaminated site characterisation approaches are time-consuming, labour-intensive, and demand a high level of expertise. This case study provides a rapid field-based solution to investigating a VOC contaminated site and its vapour incursion by combining soil vapour and groundwater survey. To fully assess the volatile organic compound (VOC) distribution in a contaminated site, a number of self-developed soil vapour sampling probes (SVSPs) were placed vertically at different locations in a grid with different depths. Hence, 3D subsurface contour maps for VOC concentrations in soil vapour can be obtained and used to help identify hot spots and the migration patterns of VOCs. This SVSP is “easy-to-install” in the field and a cost-effective solution for rapid assessment of soil vapour samples. The SVSPs can be installed both vertically and horizontally. If there is a requirement to take soil vapour samples beneath an existing building from a potential contamination source zone, SVSPs can be horizontally installed beneath the building without compromising its structural integrity. In addition, to ascertain the correct groundwater channels that are likely to carry contaminants from a potential source zone, an electrical resistivity tomography technique was employed to provide the preliminary information for groundwater delineation in a complex groundwater channel network.

Geotechnical Approach to Early-Stage Site Characterisation of Shallow Wave Energy Sites

Marine renewable energy is still in its infancy and poses serious challenges due to the harsh marine conditions encountered for wave or tidal installations and the survivability of devices. Geophysical and hydrodynamic initial site surveys need to be able to provide repeatable, reliable, and economical solutions. An oscillating water column wave energy converter is to be installed on the west coast of King Island, Tasmania. The location is in a high-energy nearshore environment to take advantage of sustained shoaling non-breaking waves of the Southern Ocean and required site-specific information for the deployment. We provide insight into scalable geophysical site surveys capable of capturing large amounts of data within a short time frame. This data was incorporated into a site suitability model, utilising seabed slope, sediment depth, and water depth to provide the terrain analysis needed to match deployment-specific characteristics. In addition, short-term hydrology and geotechnical work found a highly energetic seabed (near seafloor water velocities <1 m/s) with sufficient bearing capacity (6 MPa). In a highly energetic environment, care was taken to collect the relevant data needed for an assessment of critical information to an emerging technology companies primary project. This is in addition to the malleable methodology for a site suitability model that can incorporate various weighted parameters to prioritise the location for shallow wave energy sites in general.

Portable XRF analyzer: a powerful tool for multiscale assessment of soil contamination

&lt;p&gt;All around the world, a wide range of rural and industrial areas contaminated by PTE (potentially toxic elements) is affected by general lack of ex-ante information on type, quantity and location of potentially hazardous substances, hence the increasing request of proper investigation tools enabling preliminary screening of soil environment. Besides, spatial understanding of soil contamination is a prerequisite for the achievement of both proper site characterisation and reclamation.&lt;/p&gt;&lt;p&gt;Continuous aquisition in field of physical soil properties (such as apparent electrical conductivity by means of EMI equipments or natural gamma-ray dose rate by gamma-ray spectrometer) is of great importance to follow soil short range spatial variability. However, when the key parameter to be monitored is the soil PTE concentration (to assess, for example, exceeding of the established screening values - CSCs), a different tool is required. &amp;#160;&lt;/p&gt;&lt;p&gt;In a farmland of South of Italy, confiscated by the Italian Judiciary due to past illegal burial of industrial wastes, a portable handheld XRF analyzer (pXRF) was used at field scale to measure PTE (As, Cd, Cr, Ni, Pb) content on soil samples collected on a regular sampling grid of 20x20 m, at three depths (0-20, 30-60, 70-90 cm). On the basis of the contaminant content, distribution maps were outlined and &amp;#8220;spatial pollution hot spots&amp;#8221; revealed.&lt;/p&gt;&lt;p&gt;In correspondence of the most contaminated areas, 8 soil trenches and 5 profiles were dug. In one of the most representative soil trenches, a large (depth/height = 200 cm and width = 500 cm) wall was in situ analysed with high detail by using the pXRF at pedon scale (measurement distance of 10 cm vertically and between 20-35 cm horizontally). The use of the software Surfer 12 enabled the spatialization and mapping of the in depth contamination. Results showed a moderate but diffuse and homogeneous Cr contamination in the topsoil (400 mg/kg), a higher but point-source (2-3%) contamination in the subsoil and uncontaminated soil (40 mg/kg) below 2 m of depth. Most contaminated soil/wastes were then morphologically described and collected, bulk samples for chemical analyses and undisturbed samples for micromorphological thin sections.&lt;/p&gt;&lt;p&gt;pXRF analyzer was also used at microscopical scale on soil thin sections, using a small spot collimator (analysis area of 0.07 cm2), to preliminary detect and select contaminated micro &amp;#8211; pedofeatures, to be further sub-microscopically (SEM-EDS) analysed.&lt;/p&gt;