Research on the Changes of Some Physiological Parameters in Several Fish Species under the Action of the Funguran Fungicide

Intensive agriculture increasingly depends on chemical fertilizers and pesticides. Considerable amounts of these substances persist in the soil and, then, they reach surface water bodies, favouring eutrophication phenomenon or adversely affecting aquatic life. The existence and evolution of aquatic organisms decisively depend on the environment they live in water. This paper presents the results of the investigations regarding the changes of the physiological indices in fish under the action of the fungicide Funguran OH 50 WP (70% copper hydroxide, 50% metallic Cu). Copper hydroxide is toxic to aquatic organisms and it may cause long-term adverse effects in the aquatic environment. The toxic action of copper on fish manifests by the appearance of abundant mucus on gills and skin, cough, bleeding lips, stress, loss of balance and eventually death. Copper ions alter the ability of fish to distinguish toxic substances. In case of subacute concentrations (0.05 mg/l), the Prussian carp and other fish species are attracted to the ion source or tend to avoid it, according to the slope of the concentration gradient (low slope attraction, steep slope avoidance) and temperature, which sometimes, can reverse the reaction of fish. According to the research performed by us, it was found that the fungicide Funguran OH 50 WP has an inhibitory effect on the respiratory rate in all three investigated fish species (Carassius auratus gibelio Bloch, Perca fluviatilis L. and Alburnus alburnus L.); it also triggered the decrease of the number of erythrocytes and reduction of the glycaemic index. Perch proved to be the most sensitive fish species among the three studies species. The experiments performed show that the fungicide Funguran OH 50 WP is toxic to fish at very low concentrations.