USE OF ICP-MS FOR TRACE-ELEMENTS ANALYSIS IN KARSTIC GROUNDWATERS

Before attempting to determine trace element concentrations in karstic water samples, a number of preliminary experiments have to be carried out. The high levels of calcium in these waters can affect the accura cy of the measure due to the formation of polyatomic interferences. Sh ort-term reproducibility (a few minutes) was found to be good for all selected elements, but long-term reproducibility (a few months) indica ted problems with the determination of Ni and Cr. The low trace elemen t levels found in karstic waters were compatible with the detection li mits. To illustrate the utility of such measurements, an example of re sults obtained for a karstic aquifer at Lamalou (Herault, France) are presented and provided additional information on the structure of the aquifer.