XANTHOPHYLL CONCENTRATION IN LYMNAEA STAGNALIS CAUSED BY CHROMIUM IONS

Abstract

Currently the pollution of natural waters by heavy metal ions is a particularly serious problem which results in the disruption of the balance of food chains and the overall ecosystem balance. In this regard the study of the reaction of the biotic components of the hydroecosystem to toxic effects is relevant, and will allow to expand the understanding of the adaptive mechanisms of aquatic organisms and to determine sensitive test objects and test functions for assessing the degree of pollution of natural waters. The influence of chromium ions (Cr3+ and Cr2O72-) in concentrations corresponding to 0.5 and 2 TLV in fish farming water basins was studied based on the concentration of xanthophylls in hemolymph, hepatopancreas, mantle and leg of Lymnaea stagnalis, which is a permanent component of most hydrobiocenoses of Zhytomyr Polissia. The dynamics of the discussed carotenoids at different durations of exposure (2, 7, 14 and 21 days) of the studied shellfish in a toxic environment were observed. It was found that 48-hour exposure of shellfish in solutions of chromium ions (Cr3+ and Cr2O72- ) regardless of their concentration (0.5 and 2 TLV) causes 2.45–3.23 times increase of xanthophylls in all the studied organs and tissues of L. stagnalis (p ≤ 0.001) which indicates the development of an immediate reaction of animals to toxic elements. Further prolongation of exposure to chromium ions (7, 14, and 21 days) resulted in non-linear organ-dependent dynamics of the xanthophyll content which is related to the specificity of the action of ions, the duration of exposure of animals to toxic solutions, and the metabolic features of the studied organs and tissues. It is shown that the content of xanthophylls in the body of L. stagnalis is characterized by tissue-organ specificity. The minimum amounts of the discussed carotenoid were recorded in the hemolymph of animals and the maximum values varied significantly between the studied components depending on the experimental conditions.