Histological method for assessing the state of toxic damage to the digestive gland of shellfish sem. Unionidae

Abstract

Intense pollution of continental waters, which began in the second half of the 20th century, led to the degradation of many fishery reservoirs and gave rise to the problem of assessing water quality. Biological methods - bioindication and biotesting - are of particular importance in assessing water quality. Currently, among bioindicator organisms, especially in foreign countries, bivalve molluscs are widely used, the number of which in water bodies is decreasing, which is associated with the impact of pollutants and eutrophication. The article is devoted to the problem of assessing the water quality of fisheries reservoirs. As a bioindicator organism, the widespread bivalve mollusk sem. was used. Unionidae. Our studies on various reservoirs and water areas with different levels of pollution have shown that the effect of pollutants is clearly manifested on the state of the digestive gland of the mollusk of this family at the micro level. The analysis of numerous materials of histological studies of the gland allows us to distinguish the normal state of the gland at the micro level and to assess the pathological changes in it.

As a result of the study, for the first time, three degrees of pronounced pathological process were distinguished: 1 – light damage, 2-moderate damage, 3-heavy damage. Further studies allow us to concretize the degree of damage with the level of pollution of the shellfish habitat. As a result of the studies carried out, three stages of the pathological process in mollusks of the family were first identified. Unionidae: light, medium and heavy. The results obtained will help in assessing the toxicity of waters based on the data of the state of the digestive gland. Also, the results obtained will help to quantify the processing of histological data.