Summary:

Composting is reaching Antiquities agricultural practice mandated to produce valuable fertilizers. In the second half of the twentieth century was begun use this practice for the utilization of the organic fraction of municipal waste and sludge from sewage treatment plants and such application of this process dominates today. It does not mean, however, that ceased production of compost from "traditional" materials, they are not used as fertilizers in horticulture. The aim of the study was to estimate diversify of Cd, Pb, Zn and Cu contents in composts produced in different technologies and places but made of a similar feed material. The research material was obtained from the Krakow City (MPO Krakow) Composting Plant in Barycz, a Composting Plant at Plaszow (Krakow district) belonging to a private company Ekokonsorcjum-Effect and the three domestic composting piles located in the villages near Krakow: Bobin, Czarnochowice and Rzozow and from an allotments located at Krakow (Praska Street). Charge material for compost were taken: waste from the care of green areas of Krakow City, waste from Krakow marketplaces, which sold fruit and vegetables, weeds from weeding, the remains of cultivated plants (non-consumption parts), home waste food. The contents of the analysed elements were determined by flame atomic absorbtion spectrophotometer, the Unicam Solaar M6 apparatus. Place composting and therefore the feed material and method of composting affect the contents of the investigated metals. Composts differed significantly in terms of the content of cadmium, lead, zinc, copper and organic matter. In terms of the content of the analysed metals composts meet the requirements for them by the relevant Regulation of the Minister of Agriculture and Rural Development. As regards the minimum content of organic matter in the solid organic fertilizers reproduced in the Regulation requirements met only compost from Plaszow. According to the method IUNG the concentration of lead in the studied composts should be considered natural (00) and cadmium for elevated (I0) only composts Baryczy and Rzozów. It was also the average contamination (III0), zinc compost from Rzozów and copper compost Baryczy.