摘要
为掌握极端水文气象条件下北江上游地区重金属通量及非点源贡献,以2012年6月25日北江最大暴雨径流过程为研究对象,采用通量计算和基流分割理论,估算了北江上游高桥断面在极端暴雨条件下的溶解态重金属(Pb、Zn、Cu和Cd)通量及基流和非点源负荷,比较分析了暴雨径流前后不同阶段溶解态重金属的输运总量及特点.结果表明:暴雨径流发生前、后30 d内,溶解态Pb、Zn、Cu和Cd的通量分别达到24.1、91.4、14.6和3.4 t.暴雨径流前、后的4个典型阶段中,以地表径流为主的全流域产流期(第Ⅱ阶段)污染负荷最重,Pb、Zn、Cu和Cd日均通量较洪水前(第Ⅰ阶段)分别增长了29.6、42.6、11.6和15.4倍.深层地下水产流期(第Ⅳ阶段)Zn、Cu和Cd的输运强度较洪水前均有所下降,降幅在3.6%～33.6%之间.基流重金属污染负荷比例仅占1.7%～9.9%,非点源污染负荷在90.1%～98.3%之间,洪峰期间(第Ⅱ阶段)非点源污染负荷所占比例在96.7%以上.
Based on mass statistics and base flow separation theory,an investigative study was conducted to estimate heavy metal constituent flux,base flow and storm runoff loadings at Gaoqiao station,upstream of the Beijiang river,on June 25^ th,2012,during extreme rainfall season. The aim of the study was to understand the scale and intensity of dissolved heavy metal pollutants（ specifically Pb,Zn,Cu and Cd） transported in the stream and the contributions from diffusion sources. Meanwhile,segmental flux parameters at preand post-stages of storm runoff were also calculated. The results revealed that the constituent masses of heavy metals lead,zinc,copper and cadmium totaled 24. 1,91. 4,14. 6 and 3. 4 tons,respectively,during the 30-day storm period. As for the four distinctive stages,the flux during the flood period when river discharge was composed primarily of surface flow from the entire watershed（ the second stage） was the largest. The daily average metal mass increased 29. 6,42. 6,11. 6 and 15. 4 times compared to the non-rain period（ the first stage）.In the fourth stage,when river flow was mainly from deep groundwater,zinc,copper and cadmium flux decreased 3. 6% to 33. 6%compared to the flood stage. Flux composition analysis showed that non-point heavy metal pollutant load was overwhelmingly predominant in storm runoff（ the second stage）. The values ranged from 90. 1% to 98. 3%,which during the peak time could reach above 96. 7%;the base flow proportion was roughly between 1. 7% to 9. 9%.
出处
《环境科学研究》
EI
CAS
CSSCI
CSCD
北大核心
2014年第9期990-997,共8页
Research of Environmental Sciences
基金
2011年中央财政重金属污染防治专项
关键词
重金属
暴雨径流
通量
非点源污染
heavy metals
storm runoff
mass flux
non-point pollution
