广州城市道路雨水径流的水质特征

Water quality characteristics of road runoff from urban area of Guangzhou

城市道路雨水径流中富含交通活动所产生的大量石油类、悬浮固体和重金属等污染物,能够对受纳水体的水质造成明显的破坏并影响水生生态。对广州市内道路某路段发生的七场路面雨水径流进行了降雨量、径流量的同步监测和径流样品的水质分析,结果表明,广州城市道路雨水径流中营养盐的含量较低,但COD值较高,且可生化性差,石油类和重金属的含量也较高。其中石油类、COD、悬浮固体和重金属Pb的污染水平虽然与国内其他城市的研究结果在同一范围,但都高于国外发达国家的研究结果,反映出我国在道路路面环境维护和管理上与国外的差距。对照我国地表水环境质量标准,广州城市道路雨水径流中的石油类、COD、悬浮固体和Pb等指标都大大超过III类标准,表明道路径流若不经处理直接排放进入地表水体,可能对受纳水体主要是珠江的水质造成严重影响。

Many kinds of pollutants such as suspended solid, oil and grease and heavy metals derived from traffic activities were enriched in urban road runoff, and they could significantly degrade the quality of the receiving waters and affect hydro-ecosystem. Water quality of the road runoff from Guangzhou urban area was analyzed with synchronous measurement of the rainfall and runoff volume. The results indicated that the contents of nutritive salts were low, but COD as well as oil and grease and heavy metals were high in the runoff, and the low ratio of BOD to COD suggested low bio-degradability of the road runoff water. Although the mean concentrations of oil and grease, suspended solid and Pb generally fell within the same range of the level from other cities in China, they were considerably higher than the developed countries＇ level, reflecting the gap on environment maintenance and management of the roads between China and developed countries. Comparing with Chinese surface water quality criteria type Ⅲ, the levels of oil ＆ grease, COD, suspended solids and Pb in road runoff substantially exceeded the limited concentrations, indicating that untreated discharge of road runoff from Guangzhou urban area could seriously deteriorate the water quality of receiving waters such as Pearl River.