Effects of metals on blood oxidative stress biomarkers and acetylcholinesterase activity in dice snakes (Natrix tessellata) from Serbia

The effects of waterborne metals in water on the activities of blood copper-zinc superoxide dismutase (CuZnSOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), glutathione-S-transferase (GST), and acetylcholinesterase (AChE), and on the concentrations of total glutathione (GSH) and lipid peroxides (TBARS) in the blood of dice snakes (Natrix tessellata) caught in Obedska Bara, Sebia (control area), with snakes caught in Pancevacki Rit, a contaminated area in Serbia were examined. The activities of CAT, GSH-Px, GR and AChE, and the concentration of TBARS were significantly decreased, while GST activity and GSH concentration were significantly increased in snakes from the contaminated area compared to specimens from the control area. Significantly increased concentrations of Al, As, B, Ba, Ca, Cu, Fe, K, Li, Mn, Na, Ni and Zn in the water at the contaminated area as compared to control area were detected. The metals Ag, Bi, Cd, Co, Hg, In and Tl were not observed in any of the localities. Cr, Mo and Pb were not detected at the control area but were observed at the contaminated area. The concentrations of Sr were similar at both sites. The concentration of Mg was 2-fold higher at the control site than at the contaminated area. The obtained results show that most of the investigated blood biomarkers correlate with concentrations of metals present in the environment. These findings suggest that dice snakes are sensitive bioindicator species for monitoring the effects of increased metal concentrations in the environment.