基于WQImin模型的武汉市金银湖水质时空特性

为确定武汉市金银湖水域水质状况,提出水质评价报告,对武汉市金银湖7个水系10个典型水质指标的时空变化特征进行研究,建立了包含五日生化需氧量(BOD₅)、高锰酸盐指数(PI)、化学需氧量(COD)和溶解氧(DO)的4个主要污染指标的水质指数模型(WQI_min)。结果表明:①金银湖水质空间分布特征差异较大;位于其上游的东银湖、上金湖和墨水湖属于水质较差的污染区域(WQI_min=25.63~31.79);位于金银湖下游的东大湖、下金湖、下银湖和上银湖属于水质中等的低污染区域(WQI_min=45.64~53.19)。②金银湖水质时间格局分为3段:2019年1月水质状况最佳(WQI_min=61.68);2018年8月—2019年3月(2019年1月除外)为低污染时期(WQI_min=47.17~52.70);2019年4—10月份为水质较差的污染时期(WQI_min=24.41~35.95)。③2019年8—9月份与2018年同期相比水质下降,其原因应为外源和内源污染物的排放增长,金银湖水体治理管控需进一步加强。

Analyzing Spatio-temporal Characteristics of Water Quality in Jinyin Lake Using Water Quality Crucial Index (WQImin )

The spatial and temporal changes of ten water quality indicators obtained monthly from August 2018 to October 2019 in seven water systems of Jinyin Lake in Wuhan were investigated by constructing a water quality crucial index model (WQI_min) consisting of four crucial indices, namely, five-day biochemical oxygen demand (BOD₅), permanganate index (PI), chemical oxygen demand (COD), and dissolved oxygen (DO) using principal component analysis. Result demonstrated that the water quality in Jinyin Lake differed notably in spatial scale: Dongyin Lake, Shangjin Lake, and Moshui Lake in the upstream of Jinyin Lake belonged to polluted area of inferior water quality with the WQI_min values ranging between 25.63 and 31.79; Dongda Lake, Xiajin Lake, Xiayin Lake and Shangyin Lake in the downsteam were low-polluted areas of medium level with their average WQI_min values ranging from 45.64 to 53.19. In temporal scale, water quality in Jinyin Lake can be divided according to three time periods: January 2019 witnessed the optimum water quality with an average WQI_min value amounting to 61.68; August 2018 to March 2019 (except for January 2019) undergone low pollution with the average WQI_min value from 47.17 to 52.70; April 2019 to October 2019 presented inferior water quality with the WQI_min value from 24.41 to 35.95. The water quality in August-September 2019 declined compared with the same period in 2018 because of the increasing discharge of xenobiotic and endogenous pollutants. In conclusion, the water management of Jinyin Lake needs to be further strengthened.