There were 118 investigation items and 22 tables to be filled in the original "Preliminary Assessment (PA) Method of Soil and Groundwater Contamination Control Site". However, not all the 118 investigation items are pertinent to the PA and the proposed method is difficult to implement. By considering that most control sites have existed for years with contamination levels exceeding the control limits, the PA can be effectively carried out by using the current concentration distributions, plume areas, and the number of contaminants of the sites. Accordingly, the PA method is revised in a three-step procedure. The first step includes two qualitative evaluations in health impact. Should the control site fail to pass either of the two evaluations, it is classified as a remediation site. If passed, the PA proceeds to the second step, which checks if there is any one single contaminant concentration exceeding 20 times of its control limit. If so, the control site is classified as a remediation site. If not, the PA proceeds to the third step, which determines the soil and groundwater contamination total score, P. Should P be greater than 20, the control site is classified as the remediation site. If all the three steps are passed, the control site warrants no remediation. This project also revises the "The Methods for Environmental Impact Investigation and the Remediation Site Ranking". The revision sets forth an environmental impact investigation requirement, which includes the establishment of a relatively detailed database for the soil and groundwater contamination of the remediation site. Using the database, the soil contamination pathway impact score (SL), the groundwater contamination pathway impact score (GW), and the surface water contamination pathway impact score (SW) are calculated. The highest value of SL or GW is 100, while that of SW is 50. Should SL or GW be greater than 70, or should SW be greater than 35, the remediation site is ranked as the first class, which signifies an urgent need of immediate remediation. Otherwise, the mean square root of SL, GW, and SW is determined as the total impact score (TOL). If TOL is higher than 50, the remediation site is also ranked as the first class. If TOL is less than 50, the remediation site is ranked as the second class, which indicates no urgent need of immediate remediation and the remediation priority is lower than that of the first class.
