In order to master the environmental geochemical characteristics of heavy metals in the sediment of urban scenic areas, in this study the water area of the delta Park in Suzhou City (Anhui Province, China) as an example, the contents of Pb, U, V, Mn, Ni, Cr, Cu and Zn in sediment were tested. On this basis, using the Kriging spatial interpolation, self-organizing map (SOM) and positive matrix factorization model (PMF) to explore the spatial distribution, pollution characteristics and sources of heavy metals in the study area. The results showed that the heavy metal content of the sampling points in the estuary area was higher than that in the park; the potential ecological risk index and the geoaccumulation index evaluation results showed that the sediment of water area of the delta park was in a light pollution state; three pollution factors, including agricultural, industrial and natural sources, were analyzed by the positive matrix factorizing model, with contribution rates of 42.13%, 35.39% and 22.48% respectively, of which agricultural and industrial sources were the main sources of heavy metals in the sediments of the study area.

Although urbanization has significant effects on the landscape around the rivers, there are few studies on the fluorescence characteristics of dissolved organic matter (DOM) in watersheds under different landscape models. Therefore, in this study the optical properties of DOM in the same river under different environmental impact zones as the research object, by fluorescence excitation-emission matrix (EEM) combine with the parallel factor analysis (PARAFAC) method and mathematical statistics to research the tourist, residential and agricultural impact. The results show that agriculture has a significant effect on the concentrations of total nitrogen (TN) and chemical oxygen demand (COD) in the surface water; terrestrial humic-like and two protein-like component were derived using the PARAFAC modeling on sample fluorescence spectra, and significant differences fluorescent components in a river under different environmental impact zones. Fluorescence index analysis showed that autochthonous was the main sources of DOM. Correlation and principal component analysis (PCA) were applied to assess the relationships of fluorescent components, fluorescent indices, and water quality parameters. It revealed agricultural non-point source and the impact of human activities on the watershed.

Sulin coal-mining district is characterized by rich coal resources, and its shallow groundwater (SG) and mid-layer groundwater (MG) are the main freshwater source for drinking, agriculture, and industrial purpose. However, frequent mining activities had damaged groundwater systems. Therefore, it is necessary to understand the hydrogeochemical characteristics and determine the status of groundwater quality. To achieve a higher degree of accuracy in water quality assessment, this paper proposed a fuzzy analytical hierarchy process (AHP) which combined the fuzzy analysis model and AHP model. The results showed that Na+ and HCO3 - were the dominant cation and anion in both SG and MG, respectively. In addition, TDS, SO4 2-, Cl-, Mn, Na+, and NO3 - of SG and TDS, SO4 2-, Cl-, Mn, Na+ and F- of MG were higher than the grade III limits of Chinese groundwater standards. Analysis with molar ratios of major ions suggested that the geochemical composition of SG and MG were mainly determined by the dissolution of silicates. The fuzzy AHP evaluation results indicated that the samples of SG and MG within the III-type water accounted for 90.64% and 94.44%, respectively, and their water quality was good, which were consistent with the actual natural conditions of the study area.

Due to the large amount of water supply, the water level difference between mid-layer water and shallow water increases. There is no authoritative answer whether there is a hydraulic connection between shallow and mid-layer water. Therefore, a clear understanding of hydrogeochemical characteristics and the water chemical connection of them is indispensable for groundwater protection and the safety of water supply. The results of the statistical analysis showed that shallow and mid-layer water were both neutral water. The content of SO42−, Cl− and Na+ in both exceeded the grade III standard limit in the Standard for Groundwater Quality of China. Piper diagram revealed shallow water was mainly of Na + Mg + HCO3− and Mg + Na + HCO3− type, and mid-layer water was mainly of Na + Mg + HCO3− + SO42− and Na + Mg + HCO3− type. Besides, using the coefficient variations method of comprehensive water quality index (pH, TDS, F−, and NO3−), it is found that except for a local area with thin thickness (less than 5 m) of the first aquiclude, the mid-layer water was not affected by shallow water in Sulin mining area. This study may be helpful for the safety of water supply in the study area and other mining areas in the Huaibei coalfield.