The Suitability of Selected Naturally Growing Plant Species for the Phytostabilization of Heavy Metals at Different Locations on the Slopes of a Zinc Smelting Waste Landfill: The Second Case Study

This case study is the second of three which we have been conducting on different industrial waste landfills. We are planning a fourth study comparing the three landfills. Phytostabilization, including assisted phytostabilization, is a measure of reducing the negative impact of industrial waste landfills on the environment. It is particularly important in the case of old unprotected and often abandoned landfills. Most studies investigate how phytostability depends on the plant species but do not consider its dependence on the specific location at the landfill where the plants are growing. We assumed that the habitat conditions within the landfill had been modified unequally over the years. The most heterogeneous habitat conditions were found on the slopes of the landfill. The aims of the study were to assess the impact of the location on the landfill, i.e., the site of growth; the impact of the plant species or organ; and the combined and simultaneous impact of the location and species/organ on the phytostabilization of cadmium, lead, zinc, and copper. All bioaccumulation factor (BCF) values calculated for each metal and each location (base, middle, and top) differed statistically significantly from one another. In the case of lead, zinc, and copper the highest BCFs, irrespective of species, were obtained for plants growing at the top of the landfill, whereas the highest value for cadmium was recorded at the base. Additionally, all interactions analyzed between location and species/organ were statistically significant. Variations in the BCF values, including the variation influenced by the interaction between location and species/organ, followed four distinct patterns along the slope of the landfill from the base, to the middle, and to the top.