Establishing geochemical background variation and threshold values for 59 elements in Australian surface soil

Comparison of methods used to calculate typical threshold values for potentially toxic elements in soil.

The environmental quality of land can be assessed by calculating relevant threshold values, which differentiate between concentrations of elements resulting from geogenic and diffuse anthropogenic sources and concentrations generated by point sources of elements. A simple process allowing the calculation of these typical threshold values (TTVs) was applied across a region of highly complex geol...

Establishing Confidence in Surface Wave Determined Soil Profiles

Surface waves can be used to determine the shear velocity profile from the ground surface to some depth limited by the spectral band of the seismic source. A number of factors influence the uncertainties of the determined profile. The field acquisition factors include the deployment geometry of geophones, the spectral characteristics of the geophones, recording instruments, and seismic source. ...

Background Study Paper No. 59

Geochemical fractions of rare earth elements in soil around a mine tailing in Baotou, China

Rare earth mine tailing dumps are environmental hazards because tailing easily leaches and erodes by water and wind. To assess the influence of mine tailing on the geochemical behavior of rare earth elements (REEs) in soil, sixty-seven surface soil samples and three soil profile samples were collected from different locations near China's largest rare earth mine tailing. The total concentration...

Variable-Threshold Threshold Elements

Variable-threshold threshold elements (V-T threshold elements) are threshold elements in which the weights are fixed while the threshold may be varied. When the threshold is varied, a set of functions is generated. A concept termed complete uniformity, analogous to complete monotonicity, is shown to be a necessary condition for a set of functions to be realizable by a single V-T threshold eleme...