北京城市水体的三维荧光特征

Fluorescence Properties of Urban Water Bodies of Beijing

基于三维荧光光谱的水质荧光指纹法已经逐渐显示出作为水体有机物的新型表征方法的价值。本文研究了北京的城市水体的三维荧光指纹。结果表明,北京城市水体的荧光指纹可以分为3种类型：Ⅰ型有2个荧光峰,其中心分别位于eλx/λem=275~280/340 nm与225~230/340 nm附近,此类水体数量最多;Ⅱ型的两个荧光中心分别位于280/345~365 nm和245/380 nm附近;Ⅲ型荧光有4个荧光中心,分别位于275/305,275/340,225/305和225/340 nm附近。北京水体的荧光指纹均显示出受到人为活动干扰,Ⅰ型和Ⅲ型是介于未受干扰和生活污水的荧光指纹之间的过渡指纹。Ⅲ型更接近生活污水。而Ⅱ型的特征则主要来源于城市污水厂的再生水。这三种类型可以代表以生活污染为主的城市水体的荧光指纹。荧光指纹清晰地揭示出城市范围内无处不在人类活动的影响以及由此产生的潜在风险。这表明水质荧光指纹可以展示出污染性质和程度,可为污染源诊断提供依据。

＂Fluorescence fingerprint＂ of water body based on fluorescence excitation-emission matrix has been a novel and valuable method to exhibit the organics details.In the present study,the fluorescence matrixes of urban water bodies of Beijing were investigated.The experimental results showed that these matrixes could be divided into 3 groups： Type I owned two fluorescence centers,locating at λex/λem=275～280/340 and 225～230/340 nm respectively,and was the predominant group;fluorescence centers of Type Ⅱ located at λex/λem=280/345～365 and 245/380 nm;Type Ⅲ had four fluorescence centers around 275/305,275/340,225/305 and 225/340 nm.The fingerprints indicated that these water bodies had been disturbed by human activities.Type I and Type Ⅲ were transitional fingerprints between undisturbed water body and sewage wastewater and Type Ⅲ was closer to sewage wastewater.Type Ⅱ closely originated from reclaimed water of municipal wastewater treatment plant.These three types were main types of urban water bodies where domestic pollution was dominating.The fluorescence fingerprints clearly displayed the ubiquitous impacts of human activities and the resulting potential risk.Fluorescence fingerprint could display pollution information and serve as a possible diagnosis tool of pollution source.