Science, Technology and Engineering

Environmental Geoscience

Facilities

Environmental Geocience has a wide range of modern analytical facilities that are available to external clients and internal customers within La Trobe University, including facilities in our Analytical X-Ray Laboratory, Radiogenic Isotope Laboratory and Water Chemistry Laboratory.

Analytical X-Ray Laboratory

For details of analytical precision, availability and cost structure for the X-Ray Laboratory facilities below, please contact Dr Rob Glaisher or Ian McCabe.

X-Ray Fluoresence

The Siemens SRS303AS X-Ray Fluorescence Spectrometer (XRF) determines the elemental content of solid materials:

• quantitatively using standards,
• semi-quantitatively using a standardless procedure (Bruker SpectraPlus software), and
• qualitatively to identify the presence of elements from fluorine and upwards on the periodic table.

Major and minor element analysis (expressed as oxides - SiO₂, TiO₂, Al₂O₃, Fe₂O₃, MnO, MgO, CaO, Na₂O, K₂O, P₂O₅, SO₃ and loss on ignition, i.e. water-CO₂ ) is performed on fused glass discs.

Trace element analysis (V, Cr, Ni, Cu, Zn, Ga, Rb, Sr, Y, Nb, Mo, Pb, Th, U, Ba, La, Sc, Co, Ce, As, Nd) is performed on pressed pellets.

The following materials can be analysed:

• Rocks, minerals and sediments
• Industrial samples (sludges, slags, cement, coal)
• Soils
• Biological samples (as dried material)

Energy Dispersive X-Ray Spectroscopy (EDS)

EDS uses a scanning electron microscope to analyse sub-micron areas of solid materials, accompanied by scanning electron images with a spacial resolution of 10nm or better. Elements from carbon upwards on the periodic table can be analysed either qualitatively or quantitatively (accuracy can exceed 0.2 wt%).

The following materials can be analysed:

• Rocks, minerals and sediments
• Industrial samples (metals and alloys, ceramics, semiconductors, rubbers, plastics sludges, slags, cement, coal)
• Soils
• Biological samples (either hydrated or dried)

Carbon and water analysis

The Multiphase Carbon Determinator (LECO-412) can determine water and carbon content in solid samples of almost any type.

Mineral analysis

The Siemens D5000 X-Ray Diffractometer (XRD) uses the crystallographic properties of a sample to:

• identify the minerals present
• determine the wt% of each phase
• determine the amount of amorphous material present with use of a suitable internal standard
• determine the crystallographic parameters

The following materials can be analysed:

• Rocks, minerals, sediments
• Industrial samples (sludges, slags, cement, fly ash)
• Soils (particularly for clay identification)

The technique can be used for quality control and forensic applications.

Radiogenic Isotope Laboratory

La Trobe University has an excellent Radiogenic Isotope Laboratory based around a Thermal Ionisation Mass Spectrometer (TIMS). It comprises a fully operational Finnigan MAT 262 RPQ solid source mass-spectrometer, equipped with 7 Faraday cups and an ion counter for simultaneous collection of both large and small ion currents. The instrument uses a 13 sample barrel allowing the analysis of at least 13 samples a day. Samples are prepared in a clean-air laboratory based on class 100 HEPA clean air cabinets and extraction hoods. Ultra-pure water is provided by a Millipore water purification system and procedures are in place for the production of high-purity acids for sample dissolution and ion exchange chromatography.

The TIMS provides:

• Sm/Nd and Rb/Sr analysis of rocks for model age determinations, deposition and diagenesis, and provenance and protolith histories.
• ⁸⁷Sr/⁸⁶Sr isotope analyses of ground water for flow path tracing soils for genetic sourcing Cenozoic limestones for dating.

Turnaround times are dependant on the volume of work requested, but in general isotopic analyses can be provided 4 weeks from receipt of samples in a suitable form.

Recent clients include the Institute of Geological and Nuclear Sciences, New Zealand, State Geological Surveys nationwide, and University Earth Science Departments Australia-wide.

Please contact Dr John Webb for more information on cost and availability.

Water Chemistry Laboratory

Environmental Geoscience is also able to provide a range of water chemistry analyses and water sampling equipment.

The types of analyses include:

• General geochemical and environmental analyses
• Atomic Absorption Spectrometry (for trace metal and major cation analysis: Ca, Na, Mg, K and Fe)
• Ion Chromatography (for major anion analysis: Cl, Br, NO₃ and SO₄
• Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES for major element analysis including Si and Al)
• Solution chemistry procedures for HCO₃, pH, conductivity, redox potential and dissolved oxygen
• Auto-titrator for alkalinity or acidity titrations

The following samples can be analysed:

• Surface and ground water
• Acid Mine Drainage and other contaminated waters
• Sludge leachates
• Industrial waste leachates
• Solid samples (able to be dissolved into solution)

Field equipment available for water sampling and field measurements includes:

• pH, conductivity, redox potential and dissolved oxygen meters
• Bore-water height measurement
• Downhole electrical conductivity meter
• Bore pumps for micro-purging to large-scale drawdown tests

These facilities provide quick, accurate and cheap analyses for external and internal clients. For details of cost, availability and analytical precision, contact Dr John Webb.