南盘江水体中重金属特征污染物及控制断面的筛选

Characteristic Pollutants of Heavy Metal in Nanpan River and Selection of Controlled Cross-Section

通过建立一种新方法,即运用检出率与超标率分级评分加和排序,计算污染物筛选限值,初步筛选出具有慢性影响的污染物。然后运用DeltaTox毒性检测仪(费歇尔弧菌)测定出各污染物的EC50-5min值,计算出各污染物的急性影响程度。综合分析慢性、急性影响确定特征污染物与控制断面。运用该方法对南盘江干流8个监测点近期连续4a常规监测资料中铜、锌、铅、镉、汞、砷、六价铬的监测结果进行汇总分析,选出南盘江干流优先控制污染物为铅、砷、六价铬,其控制断面分别为:铅为柴石滩～江边街;砷为下桥闸～江边街;六价铬为下桥闸～柴石滩。

A new method is developed for initial selection of the pollutants with the chronic influence. It uses the detection ratio and over-standard ratio for classified evaluation and ranking, and calculates selection limit of the pollutants. The EC50 -5min values of the pollutants are measured by DehaTox Detector （Fischer Vibrio） to find out the acute influence of the pollutants. Then the characteristic pollutants and the controlled cross-section are identified. The method has been used for analyzing the continuous four-year monitoring data of the trunk of the southern Nanpan River at the eight monitoring points, focusing on the copper, zinc, lead, cadmium, mercury, arsenic and hexavalent chromium. The priority pollutants are lead, arsenic and chromium, and their controlled cross-sections are respectively Chaishitan-Jiangbianjie, Xiqiaozha-Jiangbianjie and Xiaqiaozha-Chaishitan.