河道水体水质对底泥污染物释放的影响

Effect of River Water Quality on the Release of Sediment Contaminants

底泥内源污染物的释放是河道污染的重要因素之一。本文通过模拟试验研究了河道水体水质对底泥污染物释放规律的影响。结果表明:上覆水体pH的升高可使底泥中COD_(Cr)和NH_4^+-N的释放受到抑制,但会促进底泥TN的释放,酸性或碱性条件都会促进底泥中TP的释放;上覆水体有机物浓度的增加可抑制底泥NH_4^+-N和TN的释放,促进TP的释放;溶解氧的增加对底泥COD_(Cr)、NH_4^+-N和TN的释放有促进作用,但会抑制底泥中TP的释放。对比分析表明,上覆水体溶解氧(<10 mg/L)对底泥COD_(Cr)、NH_4^+-N和TN的释放量影响最大,pH(4.0～10.0)对TP的释放量影响最为显著,累积释放量极差达5.89 mg/kg。

The release of inner source pollutants in sediment is one of the important causes of river pollution. The effects of river water quality on the release of pollutants from sediment were studied by simulation experiment. The results showed that the increase of pH value reduced the concentrations of CODCr and NH4^＋-N but promoted the release of TN. The increase or decrease of pH promoted the release of TP in the sediment. The increase of organic matter concentration promoted the release of TP but inhibited the release of TN and NH4^＋-N. Releases of NH4^＋-N, TN and CODCr were promoted with the increase of DO. However, aerobic condition obviously inhibited the release of TP in the sediment. It can be showed by comparative analysis that DO （ 〈 10 mg/L） in the overlying water has the greatest impact on the release of CODCr, NH4^＋-N and TN, while pH （ 4. 0- 10. 0） has the most significant impact on the release of TP, the cumulative release of TP was 5.89 mg/kg.