地表水总磷测定中现场前处理方式及分析方法比对研究

Comparative Study for Pretreatment On-site and Analysis Methods in the Determination of Total Phosphorus in Surface Water

针对目前地表水总磷测定中样品采集和分析过程普遍存在的技术问题,选取多泥沙河流(长江、黄河)、感潮河段(浙闽片区)、湖库(太湖流域)3类典型水体的多个点位,以及代表一般河流(除多泥沙河流和感潮河段以外的河流)水体的点位为研究对象,探讨不同现场前处理方式和分析方法对总磷测定结果的影响。结果表明:现场前处理方式是影响总磷测定结果的主要因素,总磷浓度与浊度呈正相关。对于地表水采样,建议一般河流(沉降30 min后,浊度<50 NTU)采用沉降30 min的现场前处理方式,泥沙含量大的水体(沉降30 min后,浊度≥50 NTU)采用4000 r/min离心2 min的现场前处理方式,多藻类湖库水体采用63μm筛过滤的现场前处理方式。可通过浊度色度补偿消除实验室比色干扰。

Aiming at the common technical problems in sampling and analysis of total phosphorus in surface water,three types of typical water bodies,including sediment-laden rivers(the Yangtze River,the Yellow River),tidal reach(Zhejiang-Fujian area),lake reservoir(the Taihu Lake),and water bodies representing general rivers(except sediment-laden rivers and tidal rivers),are selected as the research objects to explore the influence of different pretreatment on-site and analytical methods on the determination results of total phosphorus.The results show that pretreatment on-site is the main factor affecting the determination of total phosphorus,and total phosphorus concentration is positively correlated with turbidity.For surface water sampling(turbidity<50 NTU after 30 min settling),sampling method of 30 minutes subsidence is used in general rivers,water bodies with high sediment content(turbidity≥50 NTU after 30 min settling)are sampled by centrifugal sampling method of 4000 r/min and 2 min,and the algae-laden lake and reservoir water body are filtered by 63-micron sieve to remove the influence of algae clusters.The turbidity color compensation can be carried out by eliminating the interference of laboratory colorimetry.