Regional Groundwater Water Quality Assessment and Contamination Source Identification by a Self-Organizing Map and Entropy Method in Pinggu Basin, Northeast Beijing

Groundwater quality assessment is important for understanding the suitability of groundwater resources various purposes. Although many different methods have been proposed this purpose, few considered spatial variation components during assessments. In study, we to combine self-organizing map (SOM) and entropy-based weight determining method assess quality. Totally, 955 water samples taken from 58 wells 2010–2017 were used in study. 22 hydrochemical (K + , Na Ca 2+ Mg NH 4 Cl ? SO 2- F NO 3 Fe 3+ Al, etc.) each sample. These sampling points can be classified into five clusters, which may affected by four sources: landfill sources (cluster 3), industrial agricultural 5), domestic sewage discharge (clusters 1, 2, 4). The scores clusters that calculated entropy are 0.2658, 0.2634, 0.5737, 0.2608, 0.5718, indicating 4) better than other two 5) study area. results provide insights protection treatment pollution future.