Iodine and arsenic redox species in oxygen-deficient estuarine waters

Abstract

The distribution of the redox species of iodine and arsenic in two isolated pools of seawater underlying river water in deep holes in the estuary of the Yarra River is described. In the river water, the dominant species are iodide and As(V). In the saline water of these holes, there are levels of iodine and arsenic greater than are present in the original seawater. The subhalocline waters contained <0.22 ml 1-1 of dissolved oxygen, and the redox poise was intermediate between oxic and anoxic conditions. Most of the iodate originally in the seawater was reduced to iodide, but As111) and As(V) coexisted. Iodine and arsenic appear to have entered the water from the anoxic sediment.