Chlorowane weglowodory u pszczol w latach 1996-2005 w wybranej pasiece Puszczy Piskiej

The aim of this paper was to compare the residues of chlorinated hydrocarbons in bees from one of the apiaries of Piska Forest in 1996-2005. Furthermore, the content of HCH and DDT was examined in bees from this apiary where, in 2005, a very intensive cultivation of rape seed took place and by 1989 a large amount of pesticides had been applied. It was ascertained that in bees from P. apiary, which for more than ten years had been users of the same field crops (berries, lime-tree), the HCH level decreased from 0.0127 µg/g of l.s. (1996) to 0.0016 µg/g of l.s. (2005), whereas the DDT content was not reduced. This fact seems to indicate a considerably more rapid HCH decomposition in the environment. In bees staying nearly 3 weeks at the site of rape cultivation and examined after their return to the maternal apiary the content of HCH was 0.0236 µg/g of l.s. which was 15 times higher than in bees staying at the same place. The obtained results indicate that chlorinated hydrocarbons are still occurring in the environment and their amount depends on the type of pesticide used. It seems that on sandy soils the decomposition of HCH is considerably more rapid than on heavy clay soils. The diverse level of DDT in bees in P. apiary testifies to a considerable concentration of this pesticide in Piska Forest and to its slow decomposition in the environment or its permanent penetration with air streams from other regions of the world.