Difference and Correlation Analysis of Water Quality Indexes of the Xiaowan Reservoir

Abstract

为了探究澜沧江建坝对水质时空变化及其相互关联效应，采集2019年枯水期和丰水期小湾水库坝上坝下水体，分析常规指标水温(Temp)、pH、氧化还原电位(ORP)、电导率(EC)、浊度(Turb)、溶解氧(DO)及总氮(TN)、总磷(TP)和重金属的时空分布特征及其关联效应。结果表明：1) 坝上下水体酸碱性无差异且呈中性，水温变化范围是15.86℃~25.17℃，DO介于7.12~14.14 mg•L−1之间，Turb介于141~211 NTU之间，EC介于33.60~41.67 uS•cm−1之间，ORP介于198~470 mV之间，总体水质良好。2) TN变化范围在0.19~0.72 mg•L−1、TP变化范围在0.011~0.033 mg•L−1，发生水体富营养化风险较低，TN和TP均是坝上高于坝下，枯水期高于丰水期；小湾水体中重金属大多达到了II类水标准要求。3) 水质中NTU、TDS、TP和TN与水体重金属含量相关性显著，水体中重金属Hg与Ni呈显著正相关关系。 In order to explore the temporal and spatial effects of dam construction on water quality change and its correlation, the water sampling at up and down of the Xiaowan Reservoir in 2019 wet and dry seasons was carried out. The conventional water temperature (Temp), pH, REDOX potential (ORP), electrical conductivity (EC), turbidity (Turb), dissolved oxygen (DO) and total nitrogen (TN), total phosphorus (TP) and the space-time distribution characteristics of heavy metals and their associated effects were analyzed. The results show that: 1) The water temperature is varied from 15.86˚C to 25.17˚C, DO from 7.12 to 14.14 mg•L−1, Turb from 141 to 211 NTU, EC from 33.60 to 41.67 uS•cm−1 and ORP from 198 to 470 mV, and the water quality is generally good. 2) The TN and TP are ranged from 0.19 to 0.72 mg•L−1, 0.011 to 0.033 mg•L−1, respectively. The risk of water eutrophication is relatively low. Both TN and TP are higher up the dam than down the dam, and the dry season is higher than the wet season. Most of heavy metals in water body have reached the II class water standards. 3) The NTU, TDS, TP and TN are significantly correlated with heavy metal content, while Hg and Ni are significantly positively correlated.