Evaluation For Reliability Of Groundwater Quality In Korea

A few nationwide groundwater databases have been operated in Korea, but they have insufficient and lack-of-credibility water quality data. An appropriate groundwater management requires well equipped databases with reliable water quality data set. This study proposes theoretical and statistical criteria to test the reliability of water quality data. The theoretical criteria are prepared from the scientific reasoning, especially based on geochemical theories. The statistical criteria were set by the threshold values calculated from the Tukey box plot. Application of the criteria reveals that some of the data would be rejected and some others should be reevaluated. Approximately 24,000 dataset was extracted from http://www.groundwater.or.kr and used for the test. The water quality data within the threshold boundaries occupy 60.0 similar to 97.7% of the whole. The confidence range of the pH, ORP, EC, and TDS is 11.0 similar to 21.7 degrees C, 5.1 similar to 8.6, -121 similar to 218 mV (some correction needs), 0.5 similar to 565 mu S/cm, and 0.3 similar to 301 mg/L, respectively. The abnormal values outside threshold limits need to check if there is any determinated error in measurement. The main reasons for having abnormal values are probably incorrect input of the values malfunctioning of the equipments, and lack of the corresponding knowledge. To improve reliability of the dataset, it is necessary to follow verified instructions and guides to practice approach groundwater quality measurement and management, to provide regular training for the minimization of significant errors, to develop a database system being able to automatically screen abnormal values out.