METAL ACCUMULATION IN INSECTS (ORTHOPTERA, ACRIDIDAE) NEAR A COPPER SMELTER AND COPPER-FLOTATION FACTORY (PIRDOP, BULGARIA)

This study reports on accumulation of Cd, Co, Cu, Fe, Mn, Ni and Pb in insect species (grasshoppers) from different sites in the vicinity of a copper smelter and copper-flotation factory in mining region Pirdop, Bulgaria. Higher concentrations of Pb and Cd were found in the summer and autumn captured insects from the sample sites closer to the flotation factory than those from the control site, indicating, that elevated levels of these metals in this mining region is an important factor influencing body burdens. Observed differences were associated with higher metal concentrations in the plants from these sites because positive correlation between Cd and Pb concentrations in grasshoppers and plants for summer and autumn samples was found. It should be pointed that, for spring captured insects differences in Pb and Cd content for all sample saites under investigation were less significant. The concentrations of Cu, Fe, and Mn are more dependent on the feeding properties of the insects than on the distance from the emitter. In general metal body burdens for Cd, Cu, Mn, Pb and Ni were higher in summer captured insects than in spring irrespective of site or metal.