In Korea, groundwater quality is managed depending on purpose of use which is drinking, household, agriculture, fishing and industry. Since it is not considered by natural groundwater status or aquifer management, only limited action such as stop using and close wells or keep using the wells with different purpose is possible when the groundwater is contaminated. It makes groundwater aquifer being left as it is and even getting worse. The objective of this study is to research and determine the background groundwater concentration and to assess the groundwater quality. In EU and USA, Groundwater Background Levels and Threshold Values decided by statistical method have been considered as one of the significant factor for groundwater management. After review of overseas cases, groundwater quality evaluation scheme using estimation method of background groundwater concentration and Groundwater Quality Standards as shown in fig 1 and 2 is conducted. 257 samples are analyzed in study area which is about 550 km2 and consist of metamorphic and igneous rock. 64 samples remained after pre-selection and the background concentration is calculated by Cumulative Probability Distribution (CPD) and 90 percentile. All items in drinking water standards are determined and it is reflected in assessment of groundwater status of study area; 11.7 % of the area is good status (drinkable), 68.6% is moderate (drinkable), 11.9% is poor and natural status (not drinkable), 7.8% is poor and anthropogenic (not drinkable). As a result of pilot study, groundwater quality assessment and management should be reflected by natural local background concentration based on local hydrogeological characteristics to establish efficient groundwater quality management and reasonable use of groundwater.
Keywords: Groundwater quality management, background concentration
Figure 1. Background concentration determination process
Figure 2. Assessment of groundwater quality assessment