In order to produce good quality products it is necessary to find out about the quality of pastures to be grazed. It is also important to know the element composition of grazed herbs and the demands of animals bred on pastures, especially where the environment may influence the feed safety conditions of plants – as in the case of floodplains. Our objective was to determine that what the element composition (Cu, Zn, Mn and Fe contents) of herbs grown on a floodplain which was subsided by a heavy metal contaminated sediment. Our results call an attention to the differences in the accumulation of herbs. Bidens tripartitus, Lotus corniculatus and Vicia cracca grown in the floodplain showed the higher amounts of Fe and Zn, but the effect of heavy metal contamination on the element contents of other examined plants cannot be proved.