三峡库区重庆主城江段的水质分析

为了探明2010年三峡水库175m蓄水完成后重庆主城江段水质的变化特征及其成因,采用《水质采样方案设计技术规定HJ495-2009》规定的方法,于2011年1—12月逐月采集表层水样,初步研究了溶解氧(DO)、高锰酸盐指数(CODMn)、氨氮(NH4+-N)和总磷(TP)含量等指标的变化特征及其可能成因。结果表明:与2009年相比,2011年水体中DO、CODMn和NH4+-N的含量无明显变化,TP的含量出现下降。重庆主城江段水质整体污染较轻,TP的含量高于富营养化的限值,DO的含量在3—8月较低,NH4+-N的含量在1—2月较高,CODMn和TP的含量在5—10月较高。DO、CODMn、NH4+-N和TP的含量在不同水期均有显著性差异;在调查时空内,NH4+-N和DO的含量呈显著正相关(R=0.742,P<0.01),TP和CODMn的含量相关性由2009年的弱负相关(R=-0.036)转变为2011年的显著正相关(R=0.673,P<0.01)。

Analysis on Water Quality in Chongqing Urban Section of Three Gorges Reservoir

In order to study the water quality variation in the Chongqing Urban Section of Three Gorges Reservoir after the operation to raise the level of water in the Three Gorges Reservoir to 175 meters,the water samples of the surface layer sampled from January to December in 2011 were used for determining contents of DO,CODMn,NH+4-N and TP by methods in Water quality-Technical regulation on the design of sampling programmes HJ495-2009.The results showed that the concentrations of DO,CODMn and NH+4-N showed no significant changes,and concentration of total TP decreased in comparison with 2009.The water body was not strongly polluted by organic compounds.The concentration of TP was beyond the limit of eutrophication.The concentrations of DO was lower from March to August,higher concentration of NH+4-N showed in January and February,and higher concentrations of CODMn and TP showed from May to October.The concentrations of DO,CODMn,NH+4-N and TP had significant differences in the three different water seasons.Analysis of correlation revealed that the concentration of NH+4-N was significantly positively correlated with DO(R=0.742,P<0.01).Compared with weak negative correlation in 2009,the concentration of TP showed a significant positive correlation with CODMn(R=0.673,P<0.01) in 2011.