Background concentrations of heavy metals in aquatic bryophytes used for biomonitoring in basaltic areas (a case study from central France)

Studies were made of the aquatic bryophytes Fontinalis antipyretica Hedw., Platyhypnidium rusciforme (Neck.) Fleisch and Chiloscyphus sp. (Hoffm.) Dum. from streams embedded in basaltic rocks (Le Puy, central France). Water from these streams possessed elevated levels of Cu, Zn, Sr, V, Ba, Ni and Co, reflecting the geochemistry of the basalts, a basic type of igneous rocks containing elevated levels of these elements. The concentration of elements in bryophytes is correlated to the chemical composition of water of their sampling sites. Contents of trace elements in plants were higher than background values. The elevated levels of these elements possibly caused disturbances in the ionic equilibrium within the bryophytes. The molar ratio between contents of Ca and Mg in water (from 0.44 to 1) was different from that typical for natural water.