锁黄仓国家湿地公园氮污染负荷通量估算及修复策略

Load Flux of Nitrogen in Pollution Source and Remediation Measures of the Suohuangcang National Wetland Park

从氮素视角对威宁县锁黄仓国家湿地公园的地表河流、大气沉降、坡面径流和壤中流的污染物汇入通量进行估算,揭示污染负荷贡献的主次关系,为高原湿地生态系统保护提供科学参考.研究表明:1)锁黄仓湿地与其补给水体间综合污染指数差异性达显著水平,且该湿地水环境多数指标不满足国家湿地公园建设的最低要求.2)各渠道汇入锁黄仓湿地总氮通量比率依次是北门河(62.78%)>草海来水(36.62%)>坡面流和壤中流(0.53%)>大气沉降(0.07%).汇集生活污水的北门河为该湿地最重要的污染负荷输入渠道,总氮通量达2.16×10^(5)kg/a.农业活动影响下的坡面与壤中流通量为1.83×10^(4)kg/a,这与肥料流失和集水区域面积较大等因素有关.大气总氮沉降通量可能最大值仅有4.45×10^(2)kg/a,对湿地污染负荷贡献有限.3)工程建设应切断北门河补给,铺设管网直接输送至下游污水处理厂,并协调草海国家自然保护区争取更多湿地景观用水.

We have done the estimation and comparison of total nitrogen flux among various factors,such as the surface runoff,the atmospheric settlement,the slope flow and the mid-soil fluid of basin,which was contributed to contaminated environment of Suohuangcang wetland in Weining county.The aim was to reveal the contribution relation of these pollution factors,and provide reference for the protection of the plateau wetland ecosystem.The result showed that:1)The difference of the average comprehensive index among the Suohuangcang National Wetland Park,Beimen stream and Caohai supply water was significant based on the analysis of the variance.Most water indicators of the Suohuangcang wetland were below the threshold of the minimum requirements for the National Wetland Park.2)The ratio order of nitrogen fluxes imported into the wetland by each channel was Beimen stream(62.78%),Caohai supply water(36.62%),the slope and mid-soil flow of the catchment(0.53%),and the atmospheric subsidence(0.07%)in turn.The most important pollution source was Beimen stream with a total nitrogen flux of 2.16×10^(5)kg/a.The slope convergence of the pollutant originated from agriculture activity played an important role,and the total nitrogen flux has reached 1.83×10^(4)kg/a due to the fertilizer nitrogen loss and the aggregation effect of the large basin area.On the contrary,the total nitrogen from the atmospheric deposition has a limited contribution to the wetland pollution load,with the possible maximum deposition of 4.45×10^(2)kg/a only.3)If the engineering measures would be implemented to protect the wetland environment,the water supply from the Beimen stream should be cut off and the transport pipe would be equipped and distract the polluted water to downstream purifying sewage plant.The further step is that the local management of the wetland coordinates positively with the leadership department of the Caohai national nature reserve to strive for more water supply.