In this Thesis, using a number of indicators, the effects of preparations based on triazine herbicides on the fish were studied in detail. The development of agriculture is parallelly accompanied by the increase in the use of chemicals for pest and weed control. However, widespread pesticide use has a negative impact on the environment, since residual amounts of toxic chemicals and their metabolites are found in all components of ecosystems. The negative effects of pesticides on various organisms and aquatic and terrestrial ecosystems are known. As a result of direct emissions or other natural processes, pollutants enter the aquatic environment, can poison a huge number of animal species, including fish. Although they are not the largest group of aquatic organisms, they are found almost everywhere and play an important ecological role in the aquatic environment.
For the study of the toxic impact of pesticides the use of widespread fish species that are capable of reacting to the presence of contaminants on the physiological and biochemical levels is very convenient. Therefore, the main goal of this study was to evaluate the systematically effects of triazine herbicides on fish C. auratus L. For this purpose, two series of experiments were conducted in which goldfish was exposed to various concentrations of triazine herbicides Sencor and Gesagard for 96 hours. In various tissues of fish, in particular, in the blood, liver, kidneys, and gills, metabolic parameters, level of modification of biomolecules, and the state of the antioxidant system were determined in conditions of stress caused by herbicides. Attention was focused not only on the testing of the toxic effects of xenobiotics due to the possible development of oxidative stress in the organism of fish but also on the determination of biochemical parameters and some indicators of the immune system of blood fish.
At the first stage, the impact of herbicides on the oxidative stress markers and the activity of the antioxidant system in fish tissues. In particular, the effect of triazine herbicides on the content of carbonyl groups of proteins, lipids peroxides, and thiol molecules, the activity of antioxidant enzymes in gills, liver, and kidney has been shown. The results show that gill fish exhibit the best level of protection against the toxic effects of herbicide drugs. The influence of the herbicide Sencor is associated with the development of oxidative stress in the liver and kidney of fish, but it is the kidneys of fish that under the influence of Gesagard were most affected by it. This is confirmed by an increase in the content of oxidative stress markers and decreased activity of antioxidant enzymes.
The next step was to study changes in the structure of the liver and kidneys of fish in the effects of triazines. Both drugs caused destructive changes in the histological structure of the liver: hypertrophy of the liver cells, enlarged sinusoids, and damage to the vascular endothelium with isolated hemorrhages. In this case, the degree of damage to the body is higher than the action of the drug Sencor. Histopathological changes in the ultrastructure of kidneys of the experimental fish are the following: the destruction of the kidney tubules epithelium, haemorrhages, hypertrophy of intracranial hematopoietic tissue, tubules epithelium necrosis, cell damage in the Bowman capsule.
The last part of the work is devoted to the study of the impact of toxicants on hematological and some biochemical parameters of fish blood was investigated. Herbicide Sencor caused an increase in the hematocrit, while Gesagard – lowered it. The reaction of fish was practically similar at the level of the cells of the blood to selected herbicides: the growth of the relative number of rodenuclear neutrophils and monocytes. Under the influence of triazine herbicides, the concentration of glucose and triacylglycerides in the blood plasma of fish increased and the content of glycogen in the liver decreased. Herbicide Sencor resulted in increased activity of lactate dehydrogenase in the blood plasma and decreased its activity in the liver. In this case, as a result of the impact of Gesagard, the activity of the enzyme in the blood plasma was lower, and in the liver did not differ significantly from the control value. The activity of alanine and aspartate aminotransferases varied only in the case of Sencor treatment. In particular, in the blood plasma, the activity of these enzymes increased, whereas and in the liver is decreased.
An analysis of the biochemical and histological parameters of C. auratus under stress conditions caused by different concentrations of triazine herbicides was performed. Data were obtained to indicate that the fish organism was characterized by varying degrees of reaction to the toxic effects of Sencor and Gesagard at the organ level.
