Short- and long-term exposure to sub-lethal copper-sulfate concentrations studied in freshwater fish (Carassius auratus). The blood parameters, such as the content of hemoglobin-Hb and the red blood cells-RBC, were examined. Alanine transaminase-ALT and aspartate aminotransferase-AST levels in the serum were also measured. The 96-hour copper sulfate median lethal concentration-LC50 for the fish (n= 100) was calculated using different concentrations (1–10 mg/l). Two hundred and forty fish were put in 90 l-glass aquariums (10 in each aquarium) (180 fish in the experimental treatments) and (60 fish in the control treatments). Two groups of fish were formed. The first group was subjected to different concentrations of copper-sulfate for one week: 1 mg/l (0.58 copper sulfate LC50), 2 mg/l (1.15 copper sulfate LC50), and 3 mg/l (1.72 copper sulfate LC50). The second fish group received the same copper-sulfate concentrations but for four weeks. The treatment with zero copper-sulfate LC50 served as the control. Three duplicates of each treatment were achieved (A total of 340 fish were used). The results demonstrated that the content of RBC and Hb, as well as the level of the enzymes (AST and ALT), increased significantly with increasing copper-sulfate concentration in both the short- and long-term exposed fish. The current study's findings suggest that sub-lethal copper-sulfate concentrations are responsible for bloody changes and liver dysfunction in fish. The environment's copper contamination can be monitored using these parameters. 

Disinfection of cattle-breeding farms and their equipment is an action directed towards eradication of causative agents of infectious diseases in environment, towards the liquidation of the infection focal points as one of epizootic chains by means of application of various chemical substances. Study of the corrosive activity of developed in Belarus disinfectants and their comparison with the foreign analogues was realized. Cattle-breeding premises possess considerable metal consumption. Traditional disinfectants possess the expressed corrosive action and cause the substantial deterioration and damage of metal structures of premises. In recent years there were developed and recommended for application in veterinary science some new nontoxical, ecologically safe disinfectants, developed with the assistance of scientists of the S.N. Vyshelesskij Institute of Experimental Veterinary Medicine of Belarus, such as: Virkotsid (technical specifications BY 190245337.001-2007), Sandim-D (technical specifications BY 100917107.001-2007), combined disinfectant of surfaces, Valisan (technical specifications BY 101385752.001-2006), Belopag (technical specifications BY 100162869.059-2005), Belsteril (technical specifications BY 500027013.001-001-2003) and Vitmol (technical specifications BY 300047997.001-2003). Research results showed that the analysed disinfectants possessed less corrosive activity to metals in comparison with the foreign analogues (Glutex, Dezavid, Virkon C, etc.). The least severity of corrosion was stated in the disinfectants representing the compositions of the bactericide agents (Sandim-D, KDP, Belopag, Vitmol, Virkotsid, Valisan, etc)