ON THE 1995 FLOODING OF THE RIVERS MEUSE, RHINE AND WAAL IN THE NETHERLANDS - METAL CONCENTRATIONS IN DEPOSITED RIVER SEDIMENTS

After the 1995 flooding of the rivers Meuse, Rhine and Waal in the Net herlands, a survey was carried out in which samples were taken of depo sited river silt and underlying topsoils from 16 sites in the three ri ver regions. The aim of the survey was to gain an insight into the pos sible effects of deposited metals on general topsoil quality. Neutron activation analysis was used to determine concentrations of: As, Ba, B r, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn and Zr. Further sample analysis consisted of the ass essment of the particle size distributions and organic matter contents . For As, Ba, Co, Cr and Zn, the results for both silt and topsoils we re processed into so-called target- and intervention values, which ind icate intact and threatened soil functional properties, respectively. The data indicate that the deposition of river silt did not result in marked decreases in general topsoil quality.