Preliminary Assessment of the Possible Groundwater Exposure Routes from Oil and Gas Wells to Drinking Water Extraction Locations in the Netherlands

Abstract

As the source of drinking water supply in the Netherlands, the groundwater is prone to exposure from oil and gas extraction activities. The exposure is possible due to well leakage in case of a well failure that can occur in conventional and unconventional oil and gas wells. There is a lack of publicly available studies in the European context that address the possible human exposures to emissions from oil and gas extractions through groundwater. Besides, in terms of research methodology, there is a lack of studies addressing the connection between groundwater extraction for drinking water and oil and gas wells via groundwater flow. This study fills this knowledge gap by providing a preliminary assessment of the possible exposure of drinking water extraction locations in the Netherlands to oil and gas related chemicals via groundwater. With regard to the methodology, this study starts to close the knowledge gap by taking into account the direction and travel time of the groundwater flow from oil and gas wells. The direction and travel time of the groundwater flow are simulated using the Darcy Flow and Particle Track tool of ArcGIS. The time for possible contamination to reach the drinking water extraction locations is estimated by using the groundwater travel time in relation to the oil and gas well age. Exposure possibilities are further assessed based on the degradation of oil and gas related chemicals. Eighteen drinking water extraction locations (9.6%) are assessed to have possible future exposures to oil and gas wells in case failure has taken place in these locations. Fifteen out of the 18 drinking water extraction locations have higher exposure possibilities with respect to the degradation of oil and gas chemicals. Considering the low failure probability and the low exposure possibility via groundwater, the overall possibility of exposure is low. Additionally, the possible exposures in the event of a failure are all predicted to occur in the future. These results show that there is no immediate concern.