Temporal and Spatial Variation Rule of Mercury in Sediments in Middle and Lower Reaches of the Second Songhua River
第二松花江中下游沉积物汞的时空变化规律

Temporal variation rule of mercury during 1973, 1976, 1983, 1991 and 2004 in surface sediments from the Second Songhua River was get. Mercury levels increased before 1976 and decreased on a certain extent in 1976~1982; mercury pollution source was halted in 1982, so mercury levels fell greatly; in the following years, mercury levels was in the slow purification time. Sediment samples taken this time were divided into three granularity scales. Based on sediments of 63um granularity, the horizontal variation rule was analyzed. Mercury levels reached the maximum at the pollution source site, increased from Shaokou Segment to Chaoyangqiao Segment, and fell largely from Chaoyangqiao Segment to Wujiazhan Segment, where mercury levels attained the minimum. And mercury levels slightly increased from Wujiazhan Segment to Ganshuigang Segment. In addition, the vertical variation rule of mercury levels in sediments of typical segments was shown.