The Ability of Gastropods of Lake Baikal to Consume and Excrete Microplastic Particles of Different Morphological Structures

Abstract

Studies of the pollution of Lake Baikal with microplastic particles have been started quite recently. Almost all of them are focused on assessing surface water pollution, while the impact of microplastics on Baikal organisms remains unexplored. We have conducted a laboratory experiment involving three species of gastropod mollusks, the Palearctic Lymnaea stagnalis (L., 1758) and Radix auricularia (L., 1758) and the Baikal endemic Benedictia baicalensis (Gerstfeldt, 1859). Two types of microplastics are used in the experiment: fragments of polystyrene and polyester fibers prepared in the laboratory. These plastic particles, along with the food mixture, are placed in aquariums with mollusks. In total, 386 preparations with mollusk excrements have been obtained (144 preparations from Radix auricularia, 176 from Lymnaea stagnalis, and 67 from Benedictia baicalensis). The experiment with Benedictia baicalensis has been carried out only with polystyrene fragments. All preparations have been analyzed according their fluorescence ability. The data have been statistically processed using Spearman’s rank correlation coefficient. The data allow us to conclude that gastropods of these species are able both to absorb microplastic particles and remove them from the body. However, the rate of removal of microplastic particles from the body of a mollusk is species-specific and also directly depends on the morphological structure of microplastic particles.