A holistic assessment of spatio-temporal pattern and water quality in the typical basin of northeast China using multivariate statistical methods

The deterioration of water resources has been recognized as an urgent environmental problem due to population growth, industrialization, urbanization and agricultural activities, where water quality assessment is the basis for forward-looking decisions on water quality management. In this study, the Nemerow index method, traditional fuzzy mathematics and improved fuzzy mathematics methods were applied to assess the water quality of the Liao River based on twenty-three water quality parameters. The results revealed that most monitoring stations in the study area were moderately polluted. The improved fuzzy mathematics method gives more appropriate than the other two methods in water quality assessment. The self-organizing map (SOM) results suggested that chemical oxygen demand (CODCr) significantly affects water quality. The human health risk model was applied to calculate hazard indices (HI) to assess human health risks, indicating that the health risk of the Liao River caused by heavy metals was within an acceptable limit and did not pose a significant human health risk in the study area. Meanwhile, the health risk caused by heavy metals to children was higher than in adults. The results of the present study could provide new insights into water quality assessment, risk warning and public health protection in typical urbanized watersheds.