DYNAMICS OF SOME HEAVY METALS CONTENT IN FUR ANIMAL EXCRETA DURING COMPOSTING PROCESS

Fur animal excreta, due to their high content of biogenic elements as well as the possibility of microbiological and parasitologic contamination, should not be applied directly as a fertilizer. The excreta properties can be improved in composting process. European Union legislation permits fertilization use of composted fur animal excreta. The aim of the research was to determine the dynamics of some heavy metals content (Fe, Mn and Ni) during the composting process of coypu and chinchilla excreta. Composted were excreta without additions (control) as well as excreta with 20 % and 40 % addition of leaves and straw. The composting process was conducted in PVC containers in a closed place. The composting lasted 25 weeks. During that time moisture of the materials was kept at a constant level, and every two weeks the materials were mixed for aeration purpose. Samples of the materials were taken after 11, 13, 15, 23 and 25 weeks of the composting process. Heavy metals content was determined by ICP-AES method. The heavy metals content in the examined composts was decreasing in order: Fe>Mn>Ni. While analyzing the heavy metals content in composts, as a rule the lowest content of elements was determined in composts with straw addition. Moreover, from among the three components used t