1. Trakya University Department of Biology 22030 EDIRNE TURKEY
Behavioral toxicological responses of Zebrafish Danio rerio (F. Hamilton, 1822) after exposed with different concentrations of metal mixtures Utku Güner
Trakya University Department of Biology EDIRNE TURKEY
Introduction
Results
Heavy metals are natural constituents of freshwater environment, generally found in very low concentrations. Human activity has inevitably increased the levels of metal ions in many of these natural water systems. Mine drainage, river oil and gas exploration, industrial (pesticides, paints, leather, textile, fertilizers and domestic effluents, agricultural runoff, acid rain etc. have all contributed to the increased metal load in these waters being ultimately incorporated into aquatic sediments..
Aquatic organisms are often affected by trace metals due to anthropogenic activities. Environmental stress may change fish behavior. Therefore, behavioral changes and toxicological effects are useful tools for environmental risk assessment and analysis of toxicological impact. In this study, it was aimed to investigate the behavioral toxicological responses of zebra fish exposed with mixtures of Aluminum, Chromium, Cobalt, Cadmium and Arsenic metals in drinking water and irrigation water exposure limits.
During the experiments, no mortality was observed in both of control and exposure groups. Although, under laboratory conditions of constant toxicant concentrations, the drinking and irrigations water limits of metals. All groups were followed a similar track (Figure 2). The comparison of control and exposure groups showed that swimming speeds were lower in exposure groups although traveled total distances were higher(Figure 3). A B C
Control Low Mix High Mix
Figure 2 :Control group track B-Low mix group track C- B-High mix group track
Methods
The video output from the camera was fed to a computer running an animal movement tracking software (Ethovision XT Noldus). After 5 min of acclimation, the movement of each fish in aqua was recorded with the video USB camera (SN9C105 model 640 x 480 pixels) for 5 minutes(Mirenda-2 Figure 1).
The following behaviors were measured: total distance, average and maximum speed.
Chronic exposure for 20 days were done with two concentration series; within the drinking water limits of metals arsenic, cadmium, chromium, cobalt and aluminum at 10 mg/L, 5 mg/L, 50 mg/L, 10 mg/L, 300 mg/L respectively and within the allowed irrigation water limits at 100 mg/L, 10 mg/L, 100 mg/L, 50 mg/L and 5000 mg/L respectively. Behavioral changes were detected by using video-based movement analysis system(Miranda3. hardware Ethovision XT software) A B
Figure 3 :A-Total Distence of all groups, B-Mean veloitycy of all groups.
Conclusions
This behavioral exposure, tracking, and analysis automation system is made easily available for different organisms on different toxicants. sublethal exposure to chemicals often causes changes in swimming behavior, reflecting alterations in sensory and motor systems. Swimming behavior also integrates functions of the nervous system. Rarely are the connections between physiology and behavior made. Although behavior is often suggested as a sensitive, early indicator of toxicity, behavioral toxicology has not been used to its full potential because conventional methods of behavioral assessment have relied on manual techniques, which are often time-consuming and difficult to quantify. B A
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Dr. Utku Güner
Trakya University Department of Biology , Edirne Turkey
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Figure 1:A-Digital video tracing system, B-Hardware C- Aquarium D-Research laboratory