The influence of cations on chlorine toxicity

Mosquito fish were exposed to chlorine in waters of different ionic compositions and concentrations in order to determine whether intoxication is the physiological counterpart of previously reported gill damage, and whether recovery from intoxication is possible in ionically-balanced media. Marked differences to both intoxication and recovery were found, but evidence is produced that intoxicated fish have an improved chance of recovery when allowed to recuperate in ionically and osmotically appropriate salt water. A higher resistance of mosquito fish to chlorine in brackish waters is thought to be independent of oxygen demand.