长江上游紫色母质养分溶出及环境效应预测

The Forecast of Released Nutrient from Purple Parent Material in the Upper Reaches of the Yangtze River and its Environmental Effects

对侏罗系沙溪庙组 (J2 s)、蓬莱镇组 (J3p)、遂宁组 (J3s)、三叠系飞仙关组 (T1 f)母质小于 0 .2 5mm、0 .2 5～0 .5 0mm、0 .5 0～ 1.0 0mm、1.0 0～ 2 .0 0mm、2 .0 0～ 5 .0 0mm、>5 .0 0mm 6个不同粒级 ,振荡时间为 0 .5h、1h、3h、6h不同振荡时间养分 (全氮、全磷 )溶出试验 ,模拟侵蚀颗粒在水流扰动中养分释放 ,分析母质颗粒养分溶出对水体富营养化的贡献。结果表明 :振荡时间与母质颗粒溶出的全氮和全磷的含量呈正相关关系 ;粒级的大小对母质溶出的全氮和全磷的含量存在影响 ,随着粒级的增大 ,养分溶出量先增加后减小 ;以振荡 6h氮、磷最大释放量与水体富营养化临界值比较分析 ,以氮释放量计 ,紫色母岩区泥沙含量临界值在 8.30～ 11.94kg m3;以磷释放量计 ,紫色母岩区泥沙含量临界值在 2 4 .10～ 37.0 4kg m3;长江上游紫色岩区泥沙含量已接近临界泥沙含量。侵蚀母质颗粒由于受到水流的扰动 。

This paper is aimed to study the released nutrient (total N & total P) and its contribution to eutrophication of water body based on different tossing time(0.5h,1h,3h,6h)and different particle diameter(<0.25 mm,0.25- 0.50 mm,0.50- 1.00mm ,1.00-2.00mm,2.00-5.00mm,>5.00mm) of parent materials : Shaximiao group (J 2s), Penglai-zhen group (J 3p), Suining group (J 3s), and Feixianguan group (T 1f). The experiments were conducted by imitating nutrient released from eroded parent material in disturbing water. The results showed that the tossing time is positively correlated with the content of total N & P of parent material . The particle diameter has impact on the content of total N, and fotal P.The released nutrient initially increased and then decreaced with increasing particle diameter. The result shows that sand content of the Upper Yangtze River has reached proximately to its critical point . Since parent material is eroded by water body, the total N & total P are mainly responsible for the eutrophication of water body.