A field experiment was conducted to study migration of the toxic elements from the flotation tailings of copper smelter slags after sulphuric acid leaching into high-moor peat and lawn grasses. Leaching wastes were studied by X-ray fluorescence, spectral analysis, X-ray powder diffraction and scanning electron microscopy. It has been established that they contain diopside, gypsum, spinel group minerals, jarosite, barite, sphalerite and amorphous silica. 5% of wastes was introduced into lime-neutralized peat. A mixture of lawn grasses was grown on artificial soils in test plots (1 m2). Average samples of soils, shoots and roots were analyzed by inductively coupled plasma mass spectrometry. It was found that, the concentration of most elements is higher in the soil with leaching wastes than in the soil with the flotation tailings, the exceptions are Mn, Co, Ni, Cu, Zn, Cd. The greatest differences in concentration coefficients were noted for Sn (38 times) and S (5.1 times). V, Cr, Co, Ni, Se, Mn, Cu accumulated more strongly in roots on soil with leaching waste compared to both peat and soil with tailings. However, S, Mo, Cd, Sn, Sb, Ba, and Pb accumulate significantly less. The shoots grown on peat with leaching wastes have lower accumulation coefficients for most of the elements compared to both the peat and soil with flotation tailings. The research contributes to the study of the impact of copper smelter slag processing wastes on the environment and is of interest for the development of environmentally friendly and effective methods for their disposal.