Nitrate amendment was a promising and cost-effective strategy for the bioremediation of the contaminated stream sediment.Firstly, injection of nitrate into sapropelic sediments could induce vigorous denitrification in the sediments, resulted in degradation of organic matter and rapid oxidation of the upper layer of the sediments.Secondly,sediment phosphate release would be repressed by nitrate via the maintenance of an oxidized upper layer of sediment which retained phosphate in iron-oxide complexes.