Comparaison de trois méthodes pour déterminer la composition élémentaire des Bryophytes

Summary The elemental composition of 11 Bryophyte species, found on ten peatlands in the Athabasca, Alberta, Canada, was analyzed by energy dispersive X-ray spectrometry. The results were compared to those obtained by mineralisation of the same samples using a mixture of concentrated acids (HNO3 + HCIO4) and a microwave oven, followed by analyses with an inductively coupled Argon plasma spectrophotometer (ICP-AES). Accumulations of Al, Ca, Cu, Fe, K, Na, Mg, Mn, P, Pb, S and Zn were mesured in six Sphagnum species and five other Bryophyte genera, as well as surface water obtained from the sampled peatlands. Analyses of the water samples indicated that a broad spectrum of peatlands was sampled and that there were wide variations in elemental concentrations. Discrepancies between Na concentrations in the samples as determined by X-ray spectrometry and ICP-AES spectrophotometry indicated that concentrations of this element could not be accurately determined by either method. Mineralisation of the moss sample...