Interspecies calibration in mosses at regional scale—heavy metal and trace elements results from Ile-de-France

This is the first attempt in France to determine the interspecies comparisons of heavy metal and trace elemental concentrations by analysing terrestrial moss species. This study was conducted mainly around Paris, in the Ile-de-France area which is known as one of the regions in France with highly industrialized and urban locations. The mosses were collected within the framework of a European-scale campaign on background pollution carried out in France (1995–1996). A large diversity of species are usually sampled in large-scale surveys which poses problems for interspecies calibration. As regards this intercomparison study, paired samples of Hypnum cupressiforme, Pleurozium schreberi and Scleropodium purum were collected at a total of 20 sampling points. The study was on three species because large numbers of these moss species were sampled in France during the 1996 biomonitoring campaign. The samples were analysed for 36 elements using both analytical methods by instrumental neutron activation analysis (INAA) and inductively coupled plasma-mass spectrometry (ICP-MS). Element concentrations in moss species were compared using correlation by linear regression. The study showed that the pair H. cupressiforme and P. schreberi and the pair H. cupressiforme and S. purum can be used interchangeably as biomonitors in the Ile-de-France area for Al, As, Co, Cs, Fe, La, Mn, Rb, Sc, Sm, V and for Cl, Mn, Pb, Rb, Sb, Zn, respectively. In many cases interspecies calibration is not possible potentially due to saturation effect in one species, especially H. cupressiforme. Finally, the use of reliable calibration factors is recommended in Ile-de-France data sets for caesium and rubidium (Ps–Hc) or antimony, lead and rubidium (Sp–Hc) because the correlation is significant at a 99% confidence interval at least and the mean ratio calculated between both moss species differs significantly from 1.0.