Comparison of chlorine and chlorine dioxide toxicity to fathead minnows and bluegill

• Published in: Water research (Oxford) 1983, Vol.17 (10), p.1327-1331
• Main Authors: Wilde, E.W., Soracco, R.J., Mayack, L.A., Shealy, R.L., Broadwell, T.L., Steffen, R.F.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Environmental pollutants toxicology; Freshwater; Lepomis macrochirus; Medical sciences; Pimephales promelas; Toxicology; Water
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/0043-1354(83)90259-2

The comparative toxicity of total residual chlorine (TRC) and chlorine dioxide (ClO 2) was evaluated by conducting 96 h flow-through bioassays with three types of fish. The fish were subjected to an intermittent exposure regime in which biocide residuals were present for approx. 2-h periods beginning at 0, 24, 48 and 72 h into the tests. These conditions simulated the antifouling procedure (1 h day −1 biocide addition) used to control biofouling of nuclear reactor heat exchangers at the Savannah River Plant near Aiken, South Carolina. LC 50 values showed that ClO 2 was approx. 2–4 times more toxic than TRC to: (1) juvenile and 1-year-old fathead minnows ( Pimphales promelas); and (2) young-of-the-year bluegill ( Lepomis macrochirus). The TRC mean 96-h LC 50 values were: 0.08 mg l −1 for juvenile fathead minnows, 0.35 mg l −1 for adult fathead minnows and 0.44 mg l −1 for young-of-the-year bluegills. The ClO 2 mean LC 50 values were: 0.02 mg l −1 for juvenile fathead minnows, 0.17 mg l −1 for adult fathead minnows and 0.15 mg l −1 for young-of-the-year bluegills.