Applicability of different water quality evaluation methods in river-connected lakes: a case study of Dongting Lake
-
摘要:
三峡工程运行使得通江湖泊与长江原有的江湖关系发生明显变化,进而影响通江湖泊水环境,如何有效评价长江流域最大的通江湖泊洞庭湖的水质显得尤为重要。在洞庭湖湖区设置15个采样点,选取9项水质参数,运用单因子指数法、主成分分析(PCA)法、内梅罗污染指数法及Shannon-Weaver多样性指数法对2019年1—12月洞庭湖水质进行综合评价。结果显示,单因子指数法可快速准确评价水质类别,内梅罗污染指数法计算简单并在水质评价中得到广泛应用,但这2种方法均无法准确给出不同采样点间受污染程度的差异,而Shannon-Weaver多样性指数评价结果与部分采样点实际情况不符。综合考虑不同评价方法的适用性和准确性,推荐使用PCA法开展洞庭湖水质评价,该方法既能反映各主要污染指标及其贡献率,也能对不同区域水体受污染程度进行排序,且评价结果客观实际,更适用于洞庭湖区域的水质评价工作。但是在水质评价管理工作中,建议结合单因子指数法对水质类别进行判定,以保证管理的实效性。
-
关键词:
- 洞庭湖 /
- 水质评价 /
- 单因子指数法 /
- 内梅罗污染指数法 /
- 主成分分析(PCA)法
Abstract:The operation of the Three Gorges Project has significantly changed the relationship between the river-connected lakes and the Yangtze River, thus affecting the water environment of the river-connected lakes. It was particularly important to effectively evaluate the water quality of Dongting Lake, the largest river-connected Lake in the Yangtze River basin. In 2019, monthly monitoring data were collected at 15 sampling sites in Dongting Lake, including nine water quality factors. The single factor index method, principal components analysis (PCA) method, Nemero pollution index method and Shannon-Weaver biodiversity index method were used to evaluate the water quality of Dongting Lake. The single factor index method could quickly and accurately evaluate water quality categories, and the Nemerow pollution index method was simple to calculate and widely used in water quality evaluation. However, the two methods could not accurately give the difference of pollution degree between different sampling points, and the Shannon-Weaver diversity index evaluation results were not consistent with the actual situation of some sampling points. To comprehensively consider the applicability and accuracy of different evaluation methods, it was recommended to use the PCA method to carry out Dongting Lake water quality evaluation. PCA method could not only reflect the main pollution index and its contribution rate, but also rank the pollution degree of different regional water bodies, and the evaluation results were objective and practical, so it was more suitable for the water quality evaluation of Dongting Lake region. However, in the daily work of water quality evaluation management, it was suggested that the single factor index method should be combined to determine the water quality categories, so as to ensure the effectiveness of management.
-
表 1 2019年洞庭湖各采样点水质单因子指数评价结果(TN不参与评价)
Table 1. Single factor evaluation results of water quality at different sampling points in Dongting Lake in 2019 (TN was not involved in the evaluation)
湖区 采样点 枯水期 平水期 丰水期 年均值 水质类别 主要污染物 水质类别 主要污染物 水质类别 主要污染物 水质类别 主要污染物 入湖河流 S1 Ⅱ Ⅱ Ⅱ Ⅱ S2 Ⅱ Ⅱ Ⅱ Ⅱ S3 Ⅱ Ⅱ Ⅱ Ⅱ S4 Ⅱ Ⅱ Ⅱ Ⅱ 西洞庭湖 S5 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP S6 Ⅲ TP Ⅳ TP Ⅳ TP Ⅳ TP S7 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP S8 Ⅲ TP Ⅳ TP Ⅳ TP Ⅳ TP 南洞庭湖 S9 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP S10 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP 东洞庭湖 S11 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP S12 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP S13 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP S14 Ⅳ TP、CODCr Ⅴ TP、 CODCr、 CODMn Ⅴ TP、CODCr、CODMn Ⅳ TP、CODCr 出湖口 S15 Ⅳ TP Ⅳ TP Ⅳ TP Ⅳ TP 表 2 2019年洞庭湖各采样点TN和TP评价结果
Table 2. TN and TP evaluation results of sampling sites in Dongting Lake in 2019
水期 主要
污染物不同水质类别对应的采样点 Ⅲ类 Ⅳ类 Ⅴ类 劣Ⅴ类 年均值 TN S4、S7 S1、S5、S6、S8~S15 S2 TP S5~S15 枯水期 TN S7 S3~S5、S8、S9、S11~S15 S1、S2、S10 TP S6、S8 S5、S7、S9~S15 平水期 TN S3、S5~S9、S13 S1、S4、S10、S11、S14、S15 S2 TP S5~S7、S9~S13、S15 S8、S14 丰水期 TN S1、S4、S7、S13、S15 S2、S3、S5、S6、S8~S12、S14 TP S5~S13、S15 S14 表 3 不同水期旋转后的因子载荷量
Table 3. Rotated component matrix in different water periods
因子 丰水期 平水期 枯水期 PC1 PC2 PC3 PC1 PC2 PC3 PC1 PC2 PC3 水温 −0.86 −0.16 −0.30 −0.83 0.05 0.44 −0.11 0.59 0.72 pH 0.24 0.73 0.52 0.17 −0.83 0.45 −0.40 0.46 0.33 DO浓度 0.79 −0.22 −0.33 0.82 −0.21 0.43 −0.61 0.55 −0.17 CODMn 0.95 −0.18 −0.10 0.94 0.23 0.09 0.79 0.57 −0.12 CODCr 0.94 −0.18 −0.12 0.95 0.15 0.11 0.71 0.68 −0.03 BOD5 0.89 0.21 0.18 0.88 −0.26 0.04 0.49 0.60 −0.53 NH3-N浓度 −0.11 −0.45 0.72 0.89 0.23 0.12 0.77 −0.13 0.44 TP浓度 0.94 −0.05 0.02 0.74 0.19 −0.38 0.54 −0.47 −0.37 TN浓度 0.22 0.70 −0.37 −0.18 0.69 0.66 0.68 −0.41 0.50 特征值 4.88 1.41 1.18 5.31 1.45 1.19 3.25 2.41 1.53 方差百分比/% 54.27 15.68 13.12 59.04 16.12 13.23 36.13 26.73 16.99 累计方差百分比/% 54.27 69.95 83.07 59.04 75.16 88.39 36.13 62.86 79.85 注:黑体数字为环境因子在不同主成分中的载荷超过0.70的值。 表 4 年均值旋转后的因子载荷量
Table 4. Rotated component load matrix of annual mean
项目 PC1 PC2 水温 −0.86 0.21 pH 0.25 −0.74 DO浓度 0.77 −0.23 CODMn 0.96 0.17 CODCr 0.98 0.14 BOD5 0.92 −0.23 NH3-N浓度 0.61 0.59 TN浓度 −0.06 0.82 TP浓度 0.82 0.17 特征值 5.15 1.79 方差百分比/% 57.27 19.94 累计方差百分比/% 57.27 77.21 注:同表3。 -
[1] 中国环境科学研究院. 湖泊生态安全调查与评估[M]. 北京: 科学出版社, 2012. [2] WU T, WANG S R, SU B L, et al. Understanding the water quality change of the Yilong Lake based on comprehensive assessment methods[J]. Ecological Indicators,2021,126:107714. doi: 10.1016/j.ecolind.2021.107714 [3] 刘宇, 吉正元, 刘淑娟, 等.三种方法在高原湖泊水质评价中的应用与比较[J]. 海洋湖沼通报,2020(2):166-174.LIU Y, JI Z Y, LIU S J, et al. Application and comparison of three methods in water quality evaluation of plateau lakes[J]. Transactions of Oceanology and Limnology,2020(2):166-174. [4] 郑利杰, 高红杰, 宋永会, 等.我国典型城市地表水水质综合评价与分析[J]. 环境工程技术学报,2016,6(3):252-258.ZHENG L J, GAO H J, SONG Y H, et al. Comprehensive evaluation and analysis of surface water quality for typical cities of China[J]. Journal of Environmental Engineering Technology,2016,6(3):252-258. [5] 邹伟, 朱广伟, 蔡永久, 等.综合营养状态指数(TLI)在夏季长江中下游湖库评价中的局限及改进意见[J]. 湖泊科学,2020,32(1):36-47. doi: 10.18307/2020.0104ZOU W, ZHU G W, CAI Y J, et al. The limitations of comprehensive trophic level index (TLI) in the eutrophication assessment of lakes along the middle and lower reaches of the Yangtze River during summer season and recommendation for its improvement[J]. Journal of Lake Sciences,2020,32(1):36-47. doi: 10.18307/2020.0104 [6] 韩雪梅, 富国, 刘庆庆, 等.变权综合营养状态指数(TLICW)评价方法及其在三峡库区支流龙河的应用[J]. 环境工程技术学报,2018,8(6):627-634. doi: 10.3969/j.issn.1674-991X.2018.06.083HAN X M, FU G, LIU Q Q, et al. Changed weight trophic level index method and its application to Longhe tributary of the Three Gorges Reservoir area[J]. Journal of Environmental Engineering Technology,2018,8(6):627-634. doi: 10.3969/j.issn.1674-991X.2018.06.083 [7] 夏凡, 胡圣, 龚治娟, 等.不同水质评价方法的应用比较研究: 以丹江口水库入库河流为例[J]. 人民长江,2017,48(17):11-15.XIA F, HU S, GONG Z J, et al. Comparative study on application of different water quality evaluation methods: a case study of inflow rivers in Danjiangkou Reservoir area[J]. Yangtze River,2017,48(17):11-15. [8] 王丑明, 张屹, 石慧华, 等.洞庭湖大型底栖动物群落结构和水质评价[J]. 湖泊科学,2016,28(2):395-404. doi: 10.18307/2016.0220WANG C M, ZHANG Y, SHI H H, et al. Macrozoobenthic community structure and bioassessment of water quality in Lake Dongting, China[J]. Journal of Lake Sciences,2016,28(2):395-404. doi: 10.18307/2016.0220 [9] 张欢, 张佳磊, 刘德富, 等.三峡水库水温对浮游植物群落演替和多样性的影响[J]. 环境工程技术学报,2017,7(2):134-139. doi: 10.3969/j.issn.1674-991X.2017.02.020ZHANG H, ZHANG J L, LIU D F, et al. The influence of water temperature on phytoplankton community succession and diversity in Three Gorges Reservoir[J]. Journal of Environmental Engineering Technology,2017,7(2):134-139. doi: 10.3969/j.issn.1674-991X.2017.02.020 [10] 中国环境科学研究院. 2017年三峡工程生态与环境监测系统-洞庭湖江湖生态监测重点站技术报告[R]. 北京: 中国环境科学研究院, 2018. [11] 杨芳, 杨盼, 卢路, 等.基于主成分分析法的洞庭湖水质评价[J]. 人民长江,2019,50(增刊 2):42-45.YANG F, YANG P, LU L, et al. Water quality assessment of Dongting Lake based on Principal Component Analysis[J]. Yangtze River,2019,50(Suppl 2):42-45. [12] 王丽婧, 田泽斌, 李莹杰, 等.洞庭湖近30年水环境演变态势及影响因素研究[J]. 环境科学研究,2020,33(5):1140-1149.WANG L J, TIAN Z B, LI Y J, et al. Trend and driving factors of water environment change in Dongting Lake in the last 30 years[J]. Research of Environmental Sciences,2020,33(5):1140-1149. [13] 生态环境部. 长江三峡工程生态与环境监测公报(2015—2018)[R]. 北京: 生态环境部, 2015—2018. [14] 国家环境保护总局. 水和废水监测分析方法[M].4版.北京: 中国环境出版社, 2002. [15] 范志平, 王琼, 孙学凯, 等.辽河流域湿地水质污染特征及净化效果实证评估[J]. 环境工程技术学报,2020,10(6):1050-1056.FAN Z P, WANG Q, SUN X K, et al. Water pollution characteristics in wetlands and empirical evaluation of purification effect in Liaohe River Basin[J]. Journal of Environmental Engineering Technology,2020,10(6):1050-1056. [16] SHANNON C E, WEAVER W. The mathematical theory of communication[M]. Urbana: University of Illinois Press, 1949. [17] 湖南省环境保护局,湖南省质量技术监督局. 湖南省主要水系地表水环境功能区划: DB43/023—2005[S/OL]. (2005-04-01) [2022-05-20]. https://www.renrendoc.com/paper/161706246.html. [18] 王丽婧, 汪星, 刘录三, 等.洞庭湖水质因子的多元分析[J]. 环境科学研究,2013,26(1):1-7.WANG L J, WANG X, LIU L S, et al. Multivariate analysis of water factors in Dongting Lake[J]. Research of Environmental Sciences,2013,26(1):1-7. [19] 王旭, 肖伟华, 朱维耀, 等.洞庭湖水位变化对水质影响分析[J]. 南水北调与水利科技,2012,10(5):59-62.WANG X, XIAO W H, ZHU W Y, et al. Effects of water level variation on water quality in Dongting Lake[J]. South-to-North Water Diversion and Water Science & Technology,2012,10(5):59-62. [20] 钟振宇, 陈灿.洞庭湖水质及富营养状态评价[J]. 环境科学与管理,2011,36(7):169-173.ZHONG Z Y, CHEN C. Water quality and eutrophication analysis in Lake Dongting[J]. Environmental Science and Management,2011,36(7):169-173. [21] 梁明奇, 王敏, 朱江龙.基于主成分分析法的五排水库水质评价[J]. 湖北大学学报(自然科学版),2021,43(2):163-169.LIANG M Q, WANG M, ZHU J L. Water quality evaluation of Wupai Reservoirs based on Principal Component Analysis[J]. Journal of Hubei University (Natural Science),2021,43(2):163-169. [22] 李文攀, 朱擎, 李东一, 等.集中式饮用水水源地水质评价方法研究[J]. 中国环境监测,2015,31(1):24-27.LI W P, ZHU Q, LI D Y, et al. The study of assessment method of centralized source water[J]. Environmental Monitoring in China,2015,31(1):24-27. [23] 赵梦瑶, 梁恩航, 陈颖, 等.黄河玛曲至临河段硅藻群落组成及水质评价[J]. 北京大学学报(自然科学版),2022,58(1):169-176.ZHAO M Y, LIANG E H, CHEN Y, et al. Diatom community structure and water quality evaluation in the Maqu-Linhe section of the Yellow River[J]. Acta Scientiarum Naturalium Universitatis Pekinensis,2022,58(1):169-176. [24] 张新月, 蔡鑫鹏, 李曌, 等.天津子牙河浮游植物群落结构特征及水质评价[J]. 湖南生态科学学报,2022,9(1):70-76.ZHANG X Y, CAI X P, LI Z, et al. Characteristics of phytoplankton community structure and water quality assessment in Ziya River of Tianjin[J]. Journal of Hunan Ecological Science,2022,9(1):70-76. ◇