Influence of ammonia on forming the toxicity of waters from the surface sources of water supply determined on Carassius auratus gibelio (Bloch, 1782)

Purpose. Determination of the influence of ammonia in waters from surface sources of water supply of Zhytomyr city on forming the toxicity of these waters determined by test-reactions of atypical motor activity of Carassius auratus gibelio (Bloch, 1782) with the use of the «time sampling» method during 2012–2014. Methodology. Biotesting was performed at the Municipal Enterprise "Zhytomyrvodokanal". Water samples were taken once a month time from the Teteriv river reservoirs and tap water network and then placed into aquaria (8 dm3 on a group). Control and experimental groups of fish were formed according to the following scheme: control group — samples of settled (24 hours) tap water; experimental group D-1 — water samples from the Denyshivske reservoir; experimental group D-2 — water samples from the Vidsichne water intake. Test specimens were females of C. auratus gibelio. Biotesting was conducted using the «time sampling» method by keeping fish (n=30) in water for 12 hours. The toxicity indexes of waters were calculated on the basis of the following test-reactions: spiral-like and vector movements, jumping out from water, immobilization and death of fish. Statistical processing of study results were performed using cross-correlation and regression analysis in MS Excel 2007 and Statistica-6. Findings. The study showed an effect of ammonia on the toxicity of waters from reservoirs of the Teteriv river that was determined by atypical motor activity with the use of the «time sampling» method, which consisted in the instantaneous fixation of the number of individuals that favored one or another act of behavior. It was shown that females not adapted to the action of ammonia reacted to its concentration in water of more than 0.55 mg/dm3 by disorders in movements. Unlike fish of experience groups, only single pathological acts were observed in the control group. A positive moderate relationship, which had a tendency to an increase, was found between the ammonium content water of surface sources of water supply and their toxicity in 2012, and it reached high degree in 2014 (r=0.6773 in Denyshivske reservoir and r=0.6685 in Vidsichne water intake). The linear regression equations built from obtained data allow forecasting the toxicity of surface waters by ammonium concentration separately for the reservoir and water intake. Originality. Dependence of the toxicity of waters from the surface sources of water supply of Zhytomyr city on ammonium content in these waters was first determined by test-reaction of atypical motor activity of C. auratus gibelio with the use of the «time sampling» method. The linear regression equations allowed determining the dangerous threshold of ammonia concentration (0.58 mg/dm3) which resulted in 50% water toxicity for C. auratus gibelio. Practical value. Results of the study are used for biological monitoring of water toxicity of Teteriv river reservoirs.