Livestock complexes as sources of environmental pollution with heavy metals (Cu, Zn)

Trace elements Zn and Cu are widely used as part of vitaminmineral complexes for animals. About 1/3 of the trace elements of the animal diet goes into manure – a by-product of animal industry (BPA). The intake of Zn and Cu into the environment as part of the BPA from a small farm for 500 cows can reach 42.7 and 6.4 kg per year, respectively. At that, most of the BPA goes into arable land, next to animal farms. Studies of the effect of cattle manure on the content of Zn and Cu were carried out on the territory adjacent to the lagoons for the neutralization of the liquid fraction of manure effluents. It was found that in the arable land fertilized by BPA (clay soil), there was an accumulation of total forms of Si and Zn by 7 and 2.3 times, respectively, in comparison with the control. The content of mobile Cu in arable land increased by 16 times compared to the control, and the content of mobile Zn practically did not change. The detected level of trace elements in the soil did not exceed the established norms. However, the accumulation of total forms of Zn and Cu indicates that the intake of the corresponding elements from the BPA (even when using organic fertilizers in agrochemically-sound rate) exceeds their removal with the harvest of forage crops. The results of the research give reason to assume that the main contribution to the processes of mobilization /immobilization of Cu is a complex formation with organic ligands, as for Zn, it is binding on the negatively charged surface of clay particles. To prevent the possibility of contamination of territories adjacent to livestock enterprises with Zn and Cu, it is necessary to monitor the dynamics of the intake and current content of these elements in the soil.