A Comparison of Ground Water Monitoring Data from CERCLA and RCRA Sites

Ground water quality data generated during the investigation of 334 hazardous waste disposal sites were used to contrast the Resource Conservation and Recovery Act (RCRA) and Comprehensive Emergency Response, Compensation and Liability Act (CERCLA) monitoring. programs. The minimum RCRA-required network of four wells was equaled or exceeded at 94 percent of the 156 RCRA sites and 70 percent of the 178 CERCLA sites in the data base. A sampling frequency of four events per year or more was used at 60 percent of the RCRA sites compared to only 24 percent at the CERCLA sites. CERCLA records compiled to date indicate that 480 compounds have been detected and another 220 compounds have been tentatively identified in ground water in the vicinity of hazardous waste disposal sites. However, the composite data from 123 RCRA site monitoring programs only indicates the presence of 100 chemical substances. The most significant discrepancy in the RCRA detection monitoring program is that it only generates data on three of the 20 organic contaminants that have been most frequently detected during the CERCLA hazardous waste disposal site investigations. Modification of the current RCRA program to include routine analysis for volatile organic compounds would correct this weakness.