THE AVOIDANCE RESPONSE OF THE 

 COMMON SHINER TO TOTAL AND 

 COMBINED RESIDUAL CHLORINE IN 

 THERMALLY INFLUENCED DISCHARGES 



DONALD S. CHERRY, STEPHAN R. LARRICK, JAMES D. GIATTINA, 

 KENNETH L. DICKSON, and JOHN CAIRNS, Jr. 

 Biology Department and Center for Environmental Studies, Virginia 

 Polytechnic Institute and State University, Blacksburg, Virginia 



ABSTRACT 



Chlorine avoidances of the common shiner [Notropis cornutus (Mitchell)] were 

 determined in a trough containing a steep horizontal gradient at a field 

 laboratory located at the Glen Lyn Power Plant in southwestern Virginia. 

 Responses were evaluated by treating New River water with doubling increments 

 of total residual chlorine (TRC) from 0.025 to 0.40 mg/liter. Free residual 

 chlorine (FRC) was measured; combined residual chlorine (CRC) and the 

 hypochlorous acid content (HOCl) were calculated; and each of the fractions 

 comprising the TRC was correlated with fish behavior. Responses were also 

 evaluated according to ammonia nitrogen concentrations, chloramine solutions 

 with no FRC, and chlorination at preferred temperatures. Tests were carried out 

 at acclimation temperatures of 12, 18, 24, and 30°C for the unheated TRC 

 treatments and at 12 and 24°C for all other tests. The first significant or 

 threshold avoidance to TRC (represented by a significant decrease in residence 

 time in treated vs. untreated water) occurred at levels varying from 0.10 to 0.20 

 mg/liter, depending on the acclimation temperature tested. The CRC and FRC 

 comprising the TRC at the threshold avoidance level varied from 0.077 to 0.159 

 and 0.035 to 0.122 mg/liter, respectively. Variation in threshold avoidance 

 concentrations for fractions within the TRC was lowest for HOCl, 0.010 to 

 0.028 mg/liter. In chloramine trials conducted at 12 and 24 C, avoidances first 

 occurred at 0.207 and 0.205 mg/liter, respectively. When fish were acclimated at 

 12 and 24 C and tested in preferred temperatures for these acclimation 

 temperatures (17.6 and 26.8°C, respectively), TRC threshold avoidances 

 occurred at 0.211 and 0.209 mg/liter. Chloramine avoidance thresholds were 

 0.399 mg/liter at 12°C and 0.195 mg/liter at 24''C. Avoidance of ammonia was 

 not a factor in the chloramine tests since the fish did not avoid ammonia 

 nitrogen concentrations of 0.015 to 0.275 mg/liter in separate tests. The 

 avoidance responses to chlorine in ambient and preferred temperature conditions 



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