Certified Reference Waters for Mine Waters

[BronF]

Does anyone know of a suitable certified reference water to use for running mine water samples on ICP-AES/MS? I cannot find any CRWs that have a high salt content as well as high metal content - only low metals with high salts (i.e. oceanic waters) or high metals with low salts (i.e. riverine waters).

Any suggestions? Many thanks.

[Andy Barnes]

I have looked at the European Eunion Institute of Reference Materials and Measurements and they only have solid reference materials. Might be an idea to make up your own reference solution and then send it to a couple of ISO accredited laboratories. I would be intrested in seeing the ionformation on the reference solutions that you have allready found (for fresh and saline waters).

The link to the European IRMM catologue is as follows:



Andy

[BronF]

Hi Andy - The certified reference waters I currently have access to are:

Environment Canada TM28.3 (Lake Ontario water), certified for 26 elements
European Commission BCR-610 (groundwater), certified for 5 elements
LGC6019 (Thames River), certified for 11 elements
National Research Council Canada SLEW-3 (estuarine water), certified for 14 elements
National Research Council Canada SLRS-4 (river water), certified for 22 elements

The NRCC has a CASS-5 CRW which is near-shore sea water. This is more suitable for comparison to my mine waters (which are saline) but is still not a great matrix match. Just wondered how others have dealt with this issue previously. I assume they just use whatever is available at the time, irrespective of matrix.

[Chris Wolkersdorfer]

Hy BronF,

yes, this is true. People use whatever is available. The reason being simple: every mine water is different and it is not simple to find a "mean" mine water.

I will send out a mass mail to our IMWA members asking them your question (and directing them to this forum).

I think we need to think about a standard.

Glückauf

Christian Wolkersdorfer

[BronF]

Hi Chris

It's been a while since my last post and I have continued to investigate the analysis of mine waters using ICP-MS. It's true that every mine water is different in terms of metal/metalloid concentrations, however, I believe their one common feature is that the salt content is generally much higher than 'natural' riverine waters from which high metal/metalloid certified reference waters are generally sourced.

The presence of salts in the matrix is a very significant issue in terms of polyatomic interferences and salting of the cone. This is usually dealt with by increasing the dilution factor of the samples. However, this comes at a cost of losing counts for certain elements of interest. The effect of salts on measured sample concentrations can be insidious as your CRWs (which are typically low in salts) generally come back with good recovery. You only know that you have a problem when you run the same sample at two different dilution factors and get vastly different results.

There are corrections that can be applied for these interferences but inital detection of the problem can be difficult without a good CRW. The other issue and perhaps the reason for why there is yet to be a 'mine water' CRW, is that I assume a water high in salt and metal content would be hard to keep stable. Hence, getting the same measured concentration values across multiple labs would be difficult, if impossible, owing to the chemical nature of the water.

No easy answers. Just some thoughts to add to the forum.

Bron.

[Andy Barnes]

It may be worthwhile looking into developing a CRW for mine drainage or for a few certain categories of mine water. In order to do this it would probably first be necessary need to categorise mine water based on composition and salinity, then find suitable and reliable "type" sources and then (I presume) it is then just a process of filtering and acidifying a large batch (25L say) and then sending some sub samples for a round robin at a number of laboratories using the most appropriate analysis method for the given salinity of water.

It could be something that could be a collaboration through a number of willing universities and one or a number of willing regulators. There are definite advantages of undertaking this exercise and as long as a range of CRWs are produced that cover a wide range of mine water types and that their use is well constrained then these may be very useful tools.

There would also need to be a clear protocol for applying / choosing the correct CRW to use that is easy to follow (maybe based on pH, EC and sulfate or similar)

Any thoughts on this:?: