前处理方法对水体总磷测定值的影响研究

研究了水样静置30 min和全部混合立即测定2种前处理方法对江苏省环太湖15条主要出入湖河流总磷测定值的影响,结果表明,采样后静置30 min测定的总磷浓度较低,仅为全部混匀立即测定总磷浓度的46%~80%;水体中漂浮水华蓝藻数量是影响2种前处理方法总磷测定结果差异性的重要因素,去除漂浮水华蓝藻较多的7条入湖河流监测数据后,静置30 min测定的总磷浓度为全部混匀立即测定总磷浓度的71%~80%。提出,基于不同的测定目的,应有针对性地选择总磷前处理方法,在水环境质量状况评估时,可参照国家标准或最新技术规定的前处理方法执行,以保证总磷浓度的可比性;在进行总磷入湖通量研究时,建议采用全部混合立即测定的前处理方法,以反映水体中实际总磷浓度;在不同国家水体总磷浓度比较时,建议采用相同的前处理方法进行总磷浓度测定。

Pretreatment Method on Total Phosphorus Measured Value in Water

The effects of two pretreatment methods, 30 minutes standing and all mixing, on measured value of total phosphorus in 15 major rivers in and out of Lake Taihu in Jiangsu Province were studied. The results showed that the total phosphorus concentration measured after standing for 30 minutes was lower, which only accounted for 46% to 80% of the total phosphorus concentration measured immediately after mixing. The number of floating cyanobacteria in the water body is an important factor affecting the difference in the measured value of total phosphorus by the two pretreatment methods. After removing the monitoring data of 7 rivers with more floating cyanobacteria, the total phosphorus concentration measured after standing for 30 minutes accounted for 71% to 80% of the total phosphorus concentration measured after mixing. It is proposed that, based on different measurement purposes, an appropriate pretreatment method for total phosphorus should be selected. When assessing the quality of the water environment, the pretreatment methods prescribed by national standards or the latest technology can be used to ensure the comparability of total phosphorus concentrations. When conducting total phosphorus inflow studies into lakes, it is recommended to use a pretreatment method that sample is measured immediately after mixing to reflect the actual total phosphorus concentration in the water. When comparing the total phosphorus concentration in water bodies in different countries, it is recommended to use the same pretreatment method to measure the total phosphorus concentration.