应用综合指数法评价北京市二次供水水质

Quality evaluation of secondary water supply in Beijing by integrated index method

目的利用综合指数法评价北京市二次供水水质情况。方法收集2015-2019年北京市二次供水水质监测数据,运用综合指数法对结果进行综合评价和分析。结果2015-2019年全市二次供水设备出水平均综合指数为0.37±0.11;各年度水质总体平稳,平均指数均低于0.5。设备来水水质优于设备出水(0.36±0.11 vs 0.37±0.11;t=4.29,P<0.001),第一季度设备出水要优于其他季度(第一季度为0.36±0.11,第二、三、四季度分别为0.38±0.12、0.38±0.11、0.37±0.10;F=4.91,P=0.002),非中心城区的设备出水水质要优于中心城区(0.34±0.09 vs 0.40±0.12;t=16.97,P<0.001),差异均有统计学意义。考虑二次供水的特殊性,重新调整指标权重后,毒理指标对水质影响最大。结论全市二次供水水质总体优良,一般毒性指标是二次供水水质的主要影响因素。

Objective To investigate the quality of secondary water supply in Beijing by using integrated index method.Methods The monitoring data of secondary water supply from 2015 to 2019 were collected,and the water quality was analyzed and evaluated with an integrated index method.Results The average water quality index(WQI)values of water samples after facilities of secondary water supply was 0.37±0.11 from 2015 to 2019,the annual data of WQI was stable and the average values of WQI were all lower than 0.5.The quality of water samples collected before the facilities of secondary water supply were slightly better than those after the facilities(0.36±0.11 vs 0.37±0.11;t=4.29,P<0.001);the quality of water samples collected in the first quarter was better than other three quarters(0.36±0.11 of the first quarter,and 0.38±0.12、0.38±0.11、0.37±0.10 of the other seasons;F=4.91,P=0.002);and the quality of water samples in non-central city area was superior to those in center city(0.34±0.09 vs 0.40±0.12;t=16.97,P<0.001),all with statistical differences(all P<0.05).In consideration of the particularity of secondary water supply,the toxicological index had the most impact on water quality after adjusting the weights of index.Conclusions The overall quality of secondary water supply in Beijing was good,the general toxicological index was the main factor affecting the quality of secondary water supply.