The surface runoff in different function areas of Tianjin was monitored after typical rainfall to investigate the variations of pollutants concentration, event mean concentrations (EMCs) and the pollutant load of runoff caused by rainfall water. Results showed that the pollutant concentration was up to the highest value in the first 10-20 min and then descended to a stable value in a wavy pattern, which indicated an obvious scouring effect in the early step of rainfall. The EMCs of SS,COD,BOD5 were 153. 15-676. 21,70-314,10. 27-80. 65 mg/L,given the pollutant load of 793-3 369,349-1 564 and 51-402 kg/(hm2 · A)separately. The runoff water quality was below grade V of surface water environment standard; More than 50% of the monitoring results were above the first-order of national overall discharge standard of sewage. The pollutant EMCs and load of Tianjin was fairly near to the monitoring results of Guangzhou city,little higher than that of Beijing and Shanghai city,but far more than the United States,France and other developed countries. Furthermore, the most serious runoff pollution in different types of land use was industrial area, which was followed by commercial area,residential area and education area. Consequently,rainwater runoff was polluted seriously in Tianjin,and the implementation of pollution control was very important.%在对天津市不同土地利用类型地表径流水质进行监测的基础上,探讨了地表雨水径流污染物的出流规律、污染物的事件平均浓度(EMC)以及污染物负荷量.结果表明,地表径流污染物浓度大多在径流初期10～20 min达到最高值,之后随着降雨历时的延续,污染物浓度呈波浪性锯齿状降低,至降雨结束,污染物浓度最终趋于稳定,在整个径流污染过程中整体表现为初期径流污染物浓度高于后期径流,具有明显的初期冲刷效应.地表雨水径流污染物SS、COD、BOD5平均质量浓度分别为153.15～676.21、70～314、10.27～80.65 mg/L,污染负荷量分别为793～3 369、349～1 564、51～402 kg/(hm2·a),径流水质劣于《地表水环境质量标准》(GB3838-2002)Ⅴ类标准,50％以上的污染物浓度测定值超过《污水综合排放标准》(GB 8978-1996)一级标准;污染物平均浓度和负荷量与广州市监测结果相近,比北京、上海市偏高,远大于美国、法国等发达国家城市的监测值.在不同土地利用类型中,工业区地表径流污染物浓度和污染物负荷量最高,其次是商业区、居民区.研究得出,天津市地表雨水径流污染严重,实施污染控制具有十分重要的意义.
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