Groundwater Contamination Indication Using Hydrochemicalfacies Anomaly In Bandung
Bandung as one of largest city in Indonesia with rapid growth facing the same problem as other cities, huge demand for clean water and water contamination issue due to human activities. Determining pollution directly from individual water sample and testing its heavy metal content is costly. This research aim to find another simple method to effectively detect water contamination. Groundwater hydrochemicalfacies anomaly in a region with generally uniform geological condition can be used to detect this contamination. Geological condition of Bandung region was studied from regional geology map. Hydrogeological data and water sample was collected from spring, shallow well and deep well. Chemical analysis was conducted to know the water chemical composition (major element). Groundwater hydrochemicalfacies was determined from this result. Any anomaly that doesn’t match with geological setting and hydrogeological condition is assumed caused by contamination. Geological condition of Bandung mainly dominated by volcanic process and material. Rock that act as aquifer arevolcanic breccia, laharic breccia, tuff and sandy tuff. Rock layer that act as impermeable layer consist of tuff (fine), welded tuff, and lava. Shallow groundwater flow generally following topographic expressions, flowing to the center of Bandung region. Water level commonly range from 8-20m. There are three major groundwater hydrochemicalfacies from deep well. They are NaKHCO3, CaHCO3, and MgHCO3. Other minor facies also found in shallow well sample, they are CaMgSO4and CaMgCl. Both considered as anomaly. Geological and hydrogeological setting of the area is not supporting for these facies to be formed under natural condition. So we can assume that these difference was caused by contamination from the surfaces or caused by human activities.
Index Terms- contamination, groundwater, hydrochemicalfacies, volcanic.