The Angela Giblin Hydrogeochemistry database - Analytical results with a quality control assessment and database release

[摘要] The groundwater database developed by Angela Giblin comprises over 5000 samples across much of Australia, and is potentially a useful component of the “Continental Scale Hydrogeochemistry” initiative. Sampling and analytical methodology differed from most other geochemistry and from newer protocols (Gray et al., 2014). In particular, water samples were not filtered in the field, or indeed prior to analysis. However, given the number of samples and their potential utility, it would be advantageous to extract useful data from these samples.All data was combined into one file, with consistent detection limits. Data was subject to a thorough QA/QC assessment. Data that did not pass the assessment was rejected. Correction, and where necessary removal, of data (due to the analytical artifacts from solids contamination during analysis) was applied. The degree of contamination in bailed samples, and what data to therefore reject, is calculated using an algorithm developed and tested for Western Australian groundwaters. Geochemical changes between sampling and delayed analysis (days or weeks later) cannot be directly quantified. Other research predicted which elements should be most affected by this. This was further tested by comparing overlapping results from Giblin with more recent data from the same sites in Western Australia and Queensland. Results closely followed predictions - a number of parameters compared well whereas other compared badly, as predicted from theoretical considerations:-- TDS and majors, and the ratio indices (KNa etc). Saturation Index calculations for sulphates gypsum, celestine, barite also showed close agreement for less contaminated samples-- Reasonable agreement was also observed for F, HCO3, Si, V, As, Mo, Ba, U-- Poorer agreement for pH and rhodochrosite (MnCO3) SI-- Poorer still for P, Li, Cr, Au, as well as calcite, dolomite, magnesite, siderite SI-- There was very poor agreement for Co, Ni, Cu, Zn, Zr, Pb-- The elements Mn and particularly Fe show reductions in the Giblin database of one or more orders of magnitude.These results should be used to control how the Giblin data is used in further mapping and modelling. Utilising this information, the Giblin data is being combined with other databases, to map the groundwater chemistry of major regions within Australia.

[发布机构] CSIRO

[学科分类] 地球科学(综合)