Separate Effects of Acid-Derived Anions and Cations on Growth of Larval Salamanders of Ambystoma maculatum

Abstract

Hydrogen ions have been implicated as the primary source of damage associated with environmental acidification. This study suggests that anions associated with acids may also contribute to the problem of acid deposition in ecosystems. Growth rates of the larvae of Ambystoma maculatum were measured in two acids, three salts of the acids, and two acid/salt solutions. Growth rates were significantly reduced in the sulfuric acid solutions at pH 5 6.0 and in the sulfate salt solutions with sulfate ion concentrations equal to the concentrations of anions in the acid solutions. Growth rate was not reduced in the acetic acid or acetate salt solutions except in acetic acid at pH 4.5. Growth rate was reduced in acid/salt solutions independently of pH. Inhibition of growth appears to be a function of the anion concentration or the combined effect of the anion and HI but not by the pH alone. This suggests that anion radicals may be important environmental contaminants.