重庆市盘溪河水质不同季节日变化规律及水质评价

Diurnal Variation and Evaluation of Water Quality in Different Seasons of Panxi River in Chongqing

在2010年不同季节对盘溪河水质进行了采样监测,分析了盘溪河水质的季节日变化规律,运用非参数检验、方差分析和灰色关联度方法评价了盘溪河不同季节的水质日变化情况.结果表明,在不同季节中,除了Zn和Cu以外,其余各污染物都表现出显著性差异.盘溪河各水质指标季节日变化情况差别较大,DO的浓度在冬季最低,而BOD5、COD和TOC的浓度在冬季最高;NO3--N的浓度在夏季最高,而TN、NH4+-N和TP的浓度在夏季最低;Pb、Cd、Zn和Cu的日变化在不同季节波动都较大.有机污染物(BOD5、COD和TOC)和营养物质(NO3--N、TN、NH4+-N和TP)浓度的峰值多数在12:00～16:00之间;重金属(Pb、Cd、Zn和Cu)浓度的峰值多数在12:00.运用灰色关联度方法评价了盘溪河水质级别:春季在06:00和08:00为Ⅱ类,其余各时间段河流水质为劣Ⅴ类;夏季各时间段河流水质都为Ⅱ类;秋季在06:00和16:00为劣Ⅴ类,其余各时间段水质均为Ⅱ类.冬季在08:00为Ⅱ类,其余各时间段河流水质为劣Ⅴ类.

Based on the investigation of water quality of Panxi River in different seasons, 2010, we assessed the diurnal variation of water quality in different seasons and the characteristics of water quality changes within a day by using non-parametric test, analysis of variance and grey relationship analysis. The results showed that the differences were not significant for Zn and Cu （P 〉 0. 05 ） , but significant differences existed among the pH, EC, DO, COD, TP, TSS, BOD5 , NO3- -N, TN, NH4＋ -N, Pb and Cd contents. It showed that the minimum DO concentration occurred in winter, and the maximum of BOD5 ,COD and TOC concentrations occurred in winter, and the maximum NO3- -N concentration occurred in summer and the minimum TN,NH4 -N and TP concentrations occurred in summer. The diurnal variation of dissolved heavy metals showed relatively larger fluctuations in different seasons. The diurnal variation of different water quality parameters presented distinct patterns： diurnal variation of organic pollutants and nutrients showed the peak at 12：00 to 16：00 and dissolved heavy metals peaked at 12：00. The results of grey relationship analysis for surface water indicated that the water quality in spring was in the Ⅱ class at 06：00 and 08：00 and was inferior to the V class for the rest hours ; and the water quality in summer was in the Ⅱ class; and the water quality in autumn was inferior to the V class at 06：00 and 16：00 and was in the Ⅱ class for the rest hours; and the water quality in winter was in the Ⅱ class at 08：00 and was inferior to the V class for the rest hours.