When evaluating the extent of the impact of water pollutants on the surrounding area, we would like to present the target level (proposal) of the quality of the environment, which is the standard for evaluation. We propose the environmental quality target level for substances that need to be applied domestically by investigating overseas cases operating the integrated environmental management system and the implications of domestic environmental pollutant management. The appropriateness of the environmental quality target level reviewed in this study was determined using data from the water quality measuring network, and future improvement measures were proposed. We review the available methodologies for setting quality objectives for the environment. It proposed the environmental quality target level for 21 substances that have domestic water pollutant emission standards and do not have environmental standards, and proposed future improvement measures. If it is necessary to add quality target-level items of the environment in the future, it is believed that expansion will be possible based on the methodology presented in this study.

In recent years, the United States has used the Load Duration Curve (LDC) method to identify water pollution problems, considering the size of the pollutant load in the entire stream flow condition to effectively evaluate Total Maximum Daily Loads (TMDLs). A study on the improvement of the target water quality evaluation method was carried out by comparing evaluations of two consecutive years of water quality and LDC data for 41 unit watersheds (14 main streams and 27 tributaries). As a result, the achievement rate of the target water quality evaluation method, according to current regulations, was 68-93%, and that by the LDC method was 82-93%. Evaluating the target water quality using the LDC method results in a reduction in the administrative burden and the total amount of planning as compared to the current method.