Contents of Zn, Cu, Mn and Cd in soil, plants and Turkish snails Helix lucorum Linnaeus, 1758 in Skopje, Republic of North Macedonia

Heavy metal pollution of the environment is especially apparent within or around urban areas and around industrial facilities. This paper deals with the concentration of zinc, copper, manganese and cadmium in the soil, leaves of fodder plants and in the body parts of the Turkish snail (H. lucorum). The study included ten localities, arranged in four groups, situated in and around the city of Skopje. The first group consisted of five urban localities that were in the central city area. The second group included two suburban localities. The third group consisted of two rural sites. The fourth group represented one site that was located away from the metropolitan area (control site). Soils, leaves of four plant species (Cardaria draba, Lamium purpureum, Rumex crispus and Taraxacum officinale) and a sample of 10 adult snails were collected from each locality. Heavy metals content was determined by wet combustion and atomic absorption spectroscopy. Digestive gland was an organ with the highest amount of all heavy metals and with proven bioaccumulation for Zn and Cd; it showed a prominent correlation with soil concentrations for the four heavy metals but not with the examined plant species. The foot and shell of the snails had limited indicator values since they exhibited weak correlation with soil concentrations of Cu and Mn.