References
  -  K.P. Singh, A. Malik, S. Sinha, Water quality assessment and
    apportionment of pollution sources of Gomti river (India) using
    multivariate statistical techniques—a case study, Anal. Chim.
    Acta, 538 (2005) 355–374. 
-  J. Wang, L. Da, K. Song, B.-L. Li, Temporal variations of surface
    water quality in urban, suburban and rural areas during rapid
    urbanization in Shanghai, China, Environ. Pollut., 152 (2008)
    387–393. 
-  T.M. Qian, Multivariate statistical analysis of water quality in
    main and tributary stream of Qiantangjiang River in Hangzhou,
    Environ. Monit. China, 31 (2015) 74–77. 
-  G. Łukasz, W. Mirosław, P. Krzysztof, K. Andrzej, Determination
    of changes in the quality of surface water in the river—reservoir
    system, Sustainability, 13 (2021) 3457–3457. 
-  K. Huang, K.D. Fu, R. Zhu, Spatial-temporal distribution of
    water quality in the lower Lancang River based on multivariate
    statistical analysis, Water Resour. Res., 10 (2021) 53–62. 
-  D.A. Wunderlin, M.P. Dı́az, M.V. Amé, S.F. Pesce, A.C. Hued,
    M.A. Bistoni, Pattern recognition techniques for the evaluation
    of spatial and temporal variations in water quality. A case study:
    Suquı́a River Basin (Córdoba–Argentina), Water Res., 35 (2001)
    2881–2894. 
-  P.C. Cristiane, C.G. Moura, O.S. Corrêa, Assessment of spatial
    variations in the surface water quality of the Velhas River Basin,
    Brazil, using multivariate statistical analysis and nonparametric
    statistics, Environ. Monit. Assess., 191 (2019) 164, doi: 10.1007/s10661-019-7281-y. 
-  S. Zhang, Y. Liu, T. Wang, How land use change contributes to
    reducing soil erosion in the Jialing River Basin, China, Agric.
    Water Manage., 133 (2014) 65–73. 
-  X.B. Tang, H. Tang, Y. Wu, Spatio-temporal evolution of water
    resources pressure in Nanchong City, J. Univ. Chin. Acad. Sci.,
    33 (2016) 497–504. 
-  M. Li, J. Hu, C. Fan, Analysis on the discharge situation of main
    water pollutants in Nanchong during the twelfth five-year
    plan, Green Technol., 2 (2017) 16–17. 
-  B.X. Yang, Q. Liu, T.X. Dong, Functional diversity of soil
    microorganisms under different land use types in the Jialing
    River Basin, Soil Water Conserv. Res., 24 (2017) 14–20. 
-  H.M. Du, J.P. Yan, D.X. Yang, Multi-time scale analysis of
    precipitation changes and droughts and floods in the Jialing
    River Basin, J. Nat. Resour., 30 (2015) 836–845. 
-  J.Y. Li, Analysis and comprehensive evaluation of water quality
    monitoring in Nanchong section of Jialing River, Sichuan
    Environ., 33 (2014) 77–82. 
-  T.J. Xian, Z. He, C.J. Peng, Climatic characteristics of Nanchong
    City and evaluation of growth adaptability of “Nanchong
    Citrus”, J. Agron., 11 (2021) 74–79. 
-  J. Zhang, T.S. Li, C.Z. Li, Analysis of main pollutants in water
    quality of Nanchong section of Jialing River, China Environ.
    Monit., 21 (2005) 88–90. 
-  W.X. Li, Investigation on water quality and pollution discharge
    in Jialing River Basin, Water Plann. Des., 8 (2015) 37–38. 
-  GB3838-2002, Environmental Quality Standards for Surface
    Water, State Environmental Protection Administration, China,
    2002. 
-  Water and Wastewater Monitoring and Analysis Methods (Fourth
    Edition), State Environmental Protection Administration, China,
    2002. 
-  HJ 506-2009, Water Quality-Determination of Dissolved Oxygen-
    Electrochemical Probe Method, Ministry of Environmental
    Protection, China, 2009. 
-  HJ 505-2009, Water Quality-Determination of Biochemical
    Oxygen Demand after 5 Days (BOD5) for Dilution and Seeding
    Method, Ministry of Environmental Protection, China, 2009. 
-  GB 11892-1989, Water Quality-Determination of Permanganate
    Index, State Environmental Protection Administration, China,
    1989. 
-  HJ 535-2009, Water Quality-Determination of Ammonia
    Nitrogen-Nessler’s Reagent Spectrophotometry, Ministry of
    Environmental Protection, China, 2009. 
-  HJ 828-2017, Water Quality-Determination of the Chemical
    Oxygen Demand-Dichromate Method, Ministry of Environmental
    Protection, China, 2017. 
-  GB 11893-1989, Water Quality-Determination of Total
    Phosphorus-Ammonium Molybdate Spectrophotometric
    Method, State Environmental Protection Administration, China,
    1989. 
-  HJ 694-2014, Water Quality-Determination of Mercury, Arsenic,
    Selenium, Bismuth and Antimony-Atomic Fluorescence
    Spectrometry, Ministry of Environmental Protection, China,
    2014. 
-  GB/T 7484-1987, Water Quality-Determination of fluoride-Ion
    Selective Electrode Method, State Environmental Protection
    Administration, China, 1987. 
-  HJ/T 347-2007, Water Quality—Determination of Fecal
    Coliform—Manifold Zymotechnics and Filter Membrane, State
    Environmental Protection Administration, China, 2007. 
-  G. Papatheodorou, G. Demopoulou, N. Lambrakis, A long-term
    study of temporal hydrochemical data in a shallow lake using
    multivariate statistical techniques, Ecol. Modell., 193 (2006)
    759–776. 
-  N. Cliff, Analyzing multivariate data, Technometrics, 46 (2003)
    254–255. 
-  R. Johnson, Applied multivariate statistical analysis,
    Technometrics, 25 (1982) 385–386. 
-  K.P. Singh, A. Malik, V.K. Singh, D. Mohan, S. Sinha, Chemometric
    analysis of groundwater quality data of alluvial aquifer of
    Gangetic Plain, North India, Anal. Chim. Acta, 550 (2005) 82–91. 
-  W.D. Alberto, D.M. del Pilar, A.M. Valeria, P.S. Fabiana,
    H.A. Cecilia, B.M. de los Ángeles, Pattern recognition techniques
    for the evaluation of spatial and temporal variations in water
    quality, a case study: Suquı́a River Basin (Córdoba–Argentina),
    Water Res., 35 (2001) 2881–2894. 
-  Y. Yang, Y.Y. Zhou, L.Q. Zhang, Water quality analysis of
    the Yalong River in Panzhihua, China, Desal. Water Treat.,
    198 (2020) 53–60. 
-  C. Brown, Applied Multivariate Statistics in Geohydrology and
    Related Sciences, Springer, Berlin, 1998. 
-  F. Zhou, Z.J. Hao, H.C. Guo, Temporal and spatial distribution
    patterns of coastal water quality in Eastern Hong Kong, J.
    Environ. Sci., 27 (2007) 1517–1524. 
-  H.M. Zhou, L.F. Jiang, F.R. Li, Water quality status and cluster
    analysis of Huaihe River Basin in 2004, Water Resour. Prot.,
    23 (2007) 60–62. 
-  L.P. Meng, Based on cluster analysis and discriminant analysis
    method, Environ. Dev., 24 (2012) 193–194. 
-  D.J. Li, The role and analysis of dissolved oxygen in river
    water pollution, Henan Water Conserv. South-to-North Water
    Diversion, 14 (2014) 7–8. 
-  T. Yang, Q. Li, Analysis and countermeasures on exceeding
    standards of pH value and permanganate index in spring of
    small and medium-sized rivers in North China, China’s New
    Technol. New Prod., 17 (2020) 134–135. 
-  F.J. He, L.Q. Zhang, Y.X. Li, Dynamic changes and influencing
    factors of permanganate index and ammonia nitrogen in
    the mainstream of Jialing River in Nanchong City, Sichuan
	  Environ., 37 (2018) 95–101.