广州市市政供水出厂水中pH值、耗氧量和三氯甲烷的含量及其相关性分析

Analysis of pH value,oxygen consumption and trichloromethane in finished water of municipal water supply in Guangzhou

目的研究广州市市政供水厂出厂水中pH值、耗氧量和三氯甲烷的含量情况和变化趋势,初步探索pH值、耗氧量和三氯甲烷的相关关系。方法2003—2018年对广州市市政供水厂的出厂水进行抽样和检测,整理并分析480份监测样品数据。结果所有监测样品中pH值、耗氧量和三氯甲烷含量都符合《生活饮用水卫生标准》GB 5749—2006标准。出厂水中pH值和三氯甲烷均呈现上升趋势,耗氧量呈现下降趋势。pH值和三氯甲烷在不同季度之间差异有统计学意义(H=16.934,P<0.01;H=18.075,P<0.01),不同季度耗氧量差异无统计学意义(H=3.474,P>0.05)。pH值、耗氧量和三氯甲烷含量在丰水期和枯水期差异均无统计学意义(U_(pH)=28.405,P>0.05;U_(耗氧量)=27.705,P>0.05;U_(三氯甲烷)=8.201,P>0.05)。pH值与耗氧量呈负相关(r=-0.519,P<0.01),与三氯甲烷含量呈正相关(r=0.366,P<0.01);耗氧量与三氯甲烷含量呈负相关(r=-0.432,P<0.01)。结论建议广州市市政供水厂综合考虑pH值、耗氧量和三氯甲烷含量之间的相关性,密切关注出厂水质量,以保障饮用水安全。

Objective To investigate the pH value,oxygen consumption and trichloromethane content and trends in the ex-factory water of Guangzhou Municipal Water Supply Plant,and to explore the correlation between pH value,oxygen consumption and trichloromethane.Methods According to the national standard,the ex-factory water of Guangzhou Municipal Water Supply Plant was sampled and tested from 2003 to 2018,and 480 monitoring samples were collated and analyzed.Results The pH value,oxygen consumption and trichloromethane in all the monitored samples were in line with the Sanitary Standard for Drinking Water GB 5749—2006.The pH value and trichloromethane in effluent water showed increasing trends,the oxygen consumption showed a decreasing trend.The differences of pH value and trichloromethane among different quarters were statistically significant(H=16.934,P<0.01;H=18.075,P<0.01),while there were no significant differences in oxygen consumption between different quarters(H=3.474,P>0.05).There were no significant differences in pH value,trichloromethane and oxygen consumption between different water seasons(U_(pH)=28.405,P>0.05;U_(耗氧量)=27.705,P>0.05;U_(三氯甲烷)=8.201,P>0.05).pH value was negatively correlated with oxygen consumption(r=-0.519,P<0.01),and positively correlated with trichloromethane(r=0.366,P<0.01).Oxygen consumption was negatively correlated with trichloromethane(r=-0.432,P<0.01).Conclusion We advise the Guangzhou Municipal Water Supply Plant to consider the correlations between pH value,trichloromethane and oxygen consumption,and pay close attention to the quality of factory water and to ensure the safety of the drinking water.