<i>In vitro</i> evidence for the ionoregulatory role of rainbow trout mucus in acid, acid/aluminium and zinc toxicity

Abstract

Rainbow trout body mucus dialysed with acidified distilled water at pH 7,5 and 3 experienced ion depletion which was greatest at pH 3 and minimal between pH 7 and 5. Mucus Na + loss is exacerbated in the presence of 1 mg I −1 aluminium as A1 2 (SO 4 ), at pH 5 and 7. Al 2 (SO 4 ), causes greater depletion of Na + from mucus than A1C1 3 . A lethal level of zinc (2 mg 1 −1 ) does not deplete mucus Na − or K + , unlike a lethal level of aluminium (1 mg 1 −1 ) at pH 7. The results are discussed in terms of the ionoregulatory role of mucus in heavy metal and acid toxicity.