Toxicity of Residual Chlorines from Hypochloritet

Authors: Nathaniel C Añasco Jiro Koyama Shoko Imai Kuniaki Nakamura

Publish Date: 2008/05/22

Volume: 195, Issue: 1-4, Pages: 129-

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Abstract

To assess possible adverse effects of residual chlorines from hypochloritetreated seawater to nontarget marine organisms bioassays were carried out on marine amphipod Hyale barbicornis and estuarine fish Oryzias javanicus Acute toxicity tests were first conducted using various concentrations of sodium hypochlorite NaOCl followed by a longterm exposure to residual chlorines from a test water treated with 1 mg L−1 NaOCl Results showed that NaOCl was acutely toxic to both organisms However longterm exposure to residual chlorines from NaOCltreated waters caused no major adverse effects to both organisms under laboratory conditions since free chlorines in the treated water was reduced to about 10 by 23h holding and 1h aeration No H barbicornis died but residual chlorineexposed juveniles had significantly shorter body lengths at the end of exposure Residual chlorineexposed O javanicus also showed no significant differences to that of the control in all measured endpoints except for hatching time The results suggest that using 1 mg L−1 NaOCl for disinfection of ballast waters will produce residual chlorines that is far below the LC50 and EC50 of H barbicornis and O javanicus even on a longterm basis

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