Comparison of the Toxicity Characteristic Leaching Procedure (TCLP) with bioavailability determined by selective stripping, ion site partitioning analysis

Abstract

The U. S. Congress established the Resource Conservation and Recovery Act (RCRA) in 1976 to regulate hazardous wastes. In 1980 the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) was passed to target cleanup of the most heavily impacted sites. While the goals of both Acts were commendable, controversy still exists as to what constitutes "hazardous waste." In 1990, the Environmental Protection Agency mandated the use of the Toxicity Characteristic Leaching Procedure to define what wastes are hazardous. This procedure does not address the fact that some wastes may exists at sites under conditions that differ from those under which the test is performed. Hence, an expensive clean-up may be demanded when, in fact, the wastes are harmless. An example is provided from a reservoir where bottom sediments were deemed hazardous by TCLP analyses. Ion site partitioning analysis was used to identify bioavailable amounts of metals. These levels were tested on biota from the reservoir to determine actual toxic effects. The results indicated that the causes of low biological productivity were the scavenging of phosphorus by iron from the mine wastes and to lime (CaO) added to raise the reservoir pH.