大通湖主要污染物浓度空间分布及其污染来源解析

Spatial Distribution of Main Pollutants in Datong Lake and Analysis of Pollution Sources

为了解大通湖主要污染物TN、TP和NH3-N的空间分布特征及污染来源,于2017年9月对大通湖及周边河流进行采样分析。结果表明,大通湖周边入湖河流的ρ(TN)为0. 74～2. 18 mg/L,ρ(NH3-N)为0. 094～0. 874 mg/L,ρ(TP)为0. 02～0. 243 mg/L;湖体ρ(TN)为0. 82～1. 47 mg/L,呈现湖体中间低、四周高的特征,ρ(NH3-N)为0. 14～0. 42 mg/L,但整体差异较大,高值区主要在大通湖西南及东部,ρ(TP)为0. 160～0. 289 mg/L,水质为Ⅴ类或劣Ⅴ类,TP为湖体的主要污染物,湖体的ρ(TP)变化呈现出从四周向中部增加的趋势,高值区主要集中在大通湖正南及湖心处;根据2016年大通湖区域污染源统计及入湖污染物计算,大通湖水环境的TP污染负荷大小排序为农田径流>畜禽养殖>生活污水>工业污染>网箱养鱼>旅游服务。

In order to understand the spatial distribution and the pollution source of total nitrogen, total phosphorus and ammonia nitrogen in Datong Lake, samples were collected on September, 2017, from Datong Lake and its surrounding rivers. The results showed that： The total nitrogen concentration of the rivers around Datong Lake ranged from 0.74 to 2.18 mg/L, the ammonia nitrogen concentration ranged from 0.094 to 0.874 mg/L, and the total phosphorus concentration ranged from 0.02 to 0.243 mg/L. As for the lake body, the total nitrogen concentration ranged from 0.82 to 1.47 mg/L, exhibiting the characteristics of lower in the center but higher in surrounding areas in the lake body. The concentration of ammonia nitrogen ranged from 0.14 to 0.42 mg/L, but the overall difference was relatively large. The high value areas were mainly in the southwest and east of Datong Lake. The total phosphorus concentration ranged from 0.160 to 0.289 mg/L, so the water quality was classified as class V or inferior class V. The total phosphorus was the main pollutant in the lake body, which showed an increasing trend from the surrounding to the middle, and the high concentration areas were mainly concentrated in the south and middle of Datong Lake. According to the statistics of pollution sources of Datong Lake in 2016 and the calculation of pollutants discharged into the lake, the order of total phosphorus pollution load of Datong Lake is farmland runoff 〉livestock breeding 〉domestic sewage 〉 industrial pollution 〉 net cage fish culture 〉 tourism services.