南流江流域氨氮和总磷的污染源排放特征及水质管控成效分析

Characteristics of pollution source discharge for ammonia nitrogen and total phosphorus and analysis of effectiveness of water quality control in Nanliujiang River basin

南流江作为广西南部重要的入海河流,其水质对河流周边乃至整个北部湾的生态环境都有着极其重要的影响。基于实测数据,对影响南流江流域主要水质指标氨氮和总磷时空分布规律的污染特征进行了解析,总磷是南流江流域水体不达标的限制性指标,首要污染源为畜禽养殖污染。博白县的养殖污染物入河贡献量远高于其他行政区域;畜禽养殖量与支流水质关联性分析结果显示,博白县养殖业直接影响了南流江流域支流水体氨氮和总磷浓度,其中散养养殖的影响比规模化养殖的影响要大。禽畜养殖污染防治工作推进后,水质明显变好;未来需要重点关注并加强管控的重点区域是博白县,重点支流是小白江、乌豆江、水鸣河、亚山江、周村河、合水河、春石河、东平河等。

The water quality of Nanliujiang River basin,which is an important river entering the sea in the south of Guangxi,has a very important impact on the ecological environment around the surrounding areas of rivers and even the entire Beibu Gulf.Based on measured data,this study analyzed the pollution characteristics that affect the spatio-temporal distribution of the main water quality indicators(i.e.,ammonia nitrogen and total phosphorus)in the Nanliujiang River basin.Statistical analysis shows that the total phosphorus is the limiting indicator leading to unqualified water quality,and the primary pollution source is the pollution of livestock and poultry breeding.Meanwhile,the pollution load of pollutants from livestock and poultry breeding sources in Bobai County was much higher than that in other administrative regions.The results of correlation analysis be-tween livestock and poultry production and tributary water quality show that the livestock and poultry activities in Bobai County directly affect the concentration of ammonia nitrogen and total phosphorus in the tributaries of the Nanliujiang River basin.And in addition,the impact of free-range farming activities was greater than that of large-scale farming activities.After the prevention and control of livestock breeding pollution has been promo-ted,the water quality of Nanliujiang River basin has obviously improved.At the same time,the key areas that need to be focused on and strenghthened in the future are in Bobai County which is a key breeding area in Nan-liujiang River basin,with the key tributaries including Xiaobai River,Wudou River,Shuiming River,Yashan River,Zhoucun River,Heshui River,Chunshi River,Dongping River,etc.