北京密云水库流域水体夏季POM浓度及来源分析

为有效控制流域水质污染,保障饮用水水源的水质安全,通过测定北京境内密云水库流域水体夏季悬浮颗粒有机质(POM)的浓度水平及其碳、氮同位素特征,同时以京密引水渠水体为参比,对密云水库汇水流域水体POM的来源进行研究。结果表明,密云水库流域水体夏季颗粒态有机碳(POC)浓度的变化范围为0.04～0.71 mg/L,平均值为0.26 mg/L;颗粒态有机氮(PN)浓度的变化范围为0.01～0.24 mg/L,平均值为0.07 mg/L,库区水体POM浓度显著高于入库河流(P0.01),但均普遍低于国内外其他河流、湖库。夏季研究区域内水体POM主要来自内源物质,与库区相比,土壤侵蚀对入库河流POM贡献较高;与白河相比,潮河干支流陆源输入(包括生活源、土壤侵蚀等)对POM的贡献量更高。密云水库流域水体夏季POC浓度显著低于京密引水渠水体(P0.01),两种水体碳素浓度、组分可能存在差异。总体上,密云水库流域水体夏季POM浓度低且主要来源于内源。

Concentration and Source Identification of Particulate Organic Matter in the Miyun Reservoir Watershed (Beijing) in Summer

In order to control the water pollution and assure the safety of surface drinking water, the sources of suspended particulate organic matter (POM) in Miyun reservoir watershed (Beijing) in summer were studied by analyzing the concentration of POM and the stable carbon and nitrogen isotopes in surface waters in summer. In addition, the water from Jingmi diversion canal was studied as the reference. Results showed that the content of particulate organic carbon in Miyun reservoir watershed varied from 0.04 to 0.71 mg/L, with an average value of 0.26 mg/L; the content of particulate organic nitrogen in Miyun reservoir watershed varied from 0.01 to 0.24 mg/L, with an average value of 0.07 mg/L; POM concentration in the reservoir was higher than the tributary rivers, but all were generally lower than other rivers and lakes at home and abroad. POM in the study area in summer was mainly from the endogenous substances. Soil erosion contributes more POM to tributaries than to reservoir; moreover, the contribution of exogenous input (including domestic source, soil erosion, etc.) in Chao River was higher than that in Bai River. Concentrations of particulate organic carbon in Miyun reservoir watershed were significantly lower than that in Jingmi diversion canal (P<0.01), and there might be differences in carbon concentration and composition between these two waters. In general, POM concentration in Miyun reservoir watershed was low in summer and mainly came from the endogenous substances.