ALTERNATE CONCENTRATION LIMITS (ACLS)

One of the three types of standards that may be applied when a leak is detected at a treatment, storage, or disposal facility and groundwater compliance monitoring is required. ACLs are set by the U.S. Environmental Protection Agency (EPA) for specific hazardous waste constituents at levels that are designed to prevent a substantial hazard to human health or the environment. Groundwater compliance monitoring can use the following standards: (1) background concentrations, or the levels found in the area naturally; (2) specific values set by federal regulations in Title 40, Part 264.94, of the Code of Federal Regulations for eight metals and six pesticides and herbicides; or (3) alternative concentration limits.