潘大水库表层沉积物营养盐污染状况及赋存形态

潘家口-大黑汀水库(简称“潘大水库”)作为“引滦入津工程”的水源地,其水质状况直接关系到受水区饮水安全,是京津冀区域协同发展的重要影响因素.本研究基于2016年7月的调查,分析了沉积物中氮、磷和有机质的含量.结果表明: 潘大水库表层沉积物中总氮(TN)含量在1175.41～2415.67 mg·kg^-1(平均值为1648.71 mg·kg^-1),总磷(TP)含量在1773.25～3471.70 mg·kg^-1(平均值为2790.89 mg·kg^-1),有机质(OM)含量6.0%～25.3%(平均值为12.5%).在空间上,与上游的潘家口水库相比,处于下游的大黑汀水库TN含量与潘家口水库相近,TP含量略高.沉积物中氮主要以有机氮为主,磷主要以无机态的钙磷形态存在,有机质主要来源于外源性物质的输入.污染状况评价结果显示,潘大水库沉积物整体处于有机污染状态,且已达到严重污染的级别,可能会通过沉积物-水界面的营养交换对水环境改善产生潜在影响.

Contamination status and speciation for the sediment nutrients in Panjiakou-Daheiting Reservoir

As the source of the “Luanhe-Tianjin Diversion Project”, water environment status in the Panjiakou-Daheiting Reservoir directly affects drinking water safety in the water receiving area, and therefore plays important role in the development of the Beijing-Tianjin-Hebei region. Field survey was carried out in July 2016 to examine the pollution status of the sediment nitrogen, phospho-rus and organic matter. The results showed that total nitrogen (TN) content of surface sediments in Panjiakou-Daheiting Reservoir ranged from 1175.41 to 2415.67 mg·kg^-1 with a mean of 1648.71 mg·kg^-1. Total phosphorus (TP) ranged from 1773.25 to 3471.70 mg·kg^-1 with a mean of 2790.89 mg·kg^-1. Organic matter (OM) ranged from 6.0% to 25.3% with a mean of 12.5%. Daheiting Reservoir which located downstream of Panjiakou Reservoir had higher value in TP content, while had similar TN content. Results from speciation analysis showed that sediment nitrogen was mainly composed of organic nitrogen and phosphorus mainly consisted of calcium-phosphorus which belonged to inorganic phosphorus. The value of C/N ratio indicated that OM mainly originated from exogenous substances. The pollution assessment results demonstrated that the sediment Panjiakou-Daheiting Reservoir was in a severe pollution status, and might have potential effect to the water environment improvement through the nutrient exchange at the sediment-water interface.