Abstract: As a heavy industrial base and a commodity grain base in northeast China, the heavy metal pollution of water, sediment and soil in the Heilong River Basin is very worthy of attention. We collected the samples of river water, lake water, groundwater and riverbed sediment in the Heilong River Basin from the upstream arid area to the downstream Sanjiang Plain, and then analyzed the content of heavy metal elements, in order to reveal the water resources security and the degree of pollution risk of sediments by using different indexes. The results show that in the arid area of the upper reaches of the Heilong River Basin, the content of As in some surface water and groundwater exceeds the standard for drinking water quality (up to 7 times). Therefore, the safety of water for residents in upstream areas needs to be a concern. A comprehensive assessment of the indexes of Pcom and RI shows that the overall ecological risk of sediments in the Heilong River Basin was low. Among single heavy metal elements, Cd has moderate ecological risk in most watersheds, and three sediment samples show high ecological risk. Cd, as the main heavy metal element endangering the soil quality and human health in China, also needs to be paid special attention in the Heilong River Basin.

Key words: the Heilong River Basin, surface water and underground water, sediment, heavy metal pollution