Effects of Dissolved Oxygen, Light, Temperature on Iron and Manganese Release Processes of Island Reservoir Sediment

Abstract

The reservoirs in Zhoushan, Zhejiang province, China are suffering from the periodic water quality problem of iron(Fe) and manganese(Mn). In order to figure out the effects of dissolved oxygen, light and temperature on the release of dissolved iron and manganese from the sediment deposited in the reservoir, the release features of sediment samples from Xiaotiandi reservoir have been investigated in the laboratory. The results show that the dissolved oxygen, light and temperature affect the release of Fe, Mn in different ways, among which dissolved oxygen is the most sensitive factor. The release of iron and manganese can occur in both the aerobic and anoxic conditions, whereas, the primary release rate and the releasing process differs greatly. Meanwhile, higher temperature and the presence of light can accelerate the extent of iron and manganese release, which may stimulate alga bloom and the metabolic activities of microbials. The competition release of iron and manganese happens obviously in the anoxic condition. The manganese releases quickly at the beginning of the process till to a relative stable rate while the release of iron begins.