The use of ICP-MS for the analysis of natural waters and an evaluation of sampling techniques.

Analytical and sampling methods for a reconnaissance survey of river waters in former metal mining areas of Wales, UK, are considered. A 'semi-quantitative' mode of analysis with a single internal standard, possible by inductively coupled plasma mass spectrometry (ICP-MS) is compared with more conventional 'quantitative' ICP-MS methods using external calibration from aqueous standards. 'Semi-quantitative' analysis can be much quicker than a more rigorous quantitative approach and gives values which agree with fully quantitative data to within 30%, indeed, agreement is often much better than this. A comparison of samples filtered and acidified in the field with untreated samples is also presented. This shows that in most cases it is unnecessary to filter and acidify samples if the storage time before analysis is short (in this case typically less than four days).