During recent years the attention towards the effects of xenobiotic substances on wild nature has been steadily increasing. Literature reviews have revealed that active hormone-disintegrating substances might affect the reproduction of some wild animal species. Research shows anomalies of reproduction and development in various animal groups such as birds, fish, invertebrates and reptiles. Species inhabiting water and its surroundings cause the highest concern. Due to insufficient baseline information it is difficult to determine the extent of the problem in these wild populations on an ecological scale. The research described in this article is the first attempt to analyse xenobiotic substances and evaluate possible accumulation of pharmaceuticals in animals higher up in the food chain in Lithuania. This research tests new methods for to analyse for xenobiotics substances, which might be used in the future. Blood samples of 7 swans were examined using liquid chromatography, however, no xenobiotics were detected. Negative results do not eliminate the necessity for further investigate of larger samples, other species or to search for non-pharmaceutical xenobiotics.
Environmental coupling of heritability and selection is rare and of minor evolutionary significance in wild populations
