Contaminated Soil

Prior to the 1970s, inappropriate waste disposal practices like dumping untreated liquids in lagoons and landfills were common and widespread. Some of these practices were undertaken with willful disregard for their environmental consequences, and occasionally for existing regulations, but many types of soil contamination occurred as a result of scientific ignorance. The toxicity of many contaminants, including PCBs and methyl mercury, was discovered long after the chemicals were spilled, dumped, or sprayed into soils. The ability of groundwater flow to transport contaminants was likewise unknown until decades after many contaminants had flowed away from unlined landfills, sewage outlets and chemical dumps.

The presence and potential impacts of soil contamination were finally brought to public attention after well-publicized disasters at Love Canal, New York, the Valley of the Drums, Kentucky, and Times Beach, Missouri. Congress responded by passing the Comprehensive Environmental Response, Compensation, and Liability Act in 1980 (commonly known as CERCLA, or Superfund) to provide funds with which to remediate contamination at the worst sites of point-source pollution. After five years of much litigation but little action, Congress updated CERCLA in 1986 with the Superfund Amendments and Reauthorization Act.

In 2003, a total of 1,300 sites across the United States were designated as National Priorities List (NPL) sites that were eligible under CERCLA for federal cleanup assistance. These Superfund sites are considered the nation's largest and most contaminated sites in terms of the possibility for adverse human and environmental impacts. They are also the most expensive sites to clean. While not as well recognized, numerous other sites have serious soil contamination problems.

The U.S. Office of Technology Assessment and the Environmental Protection Agency (EPA) have estimated that about 20,000 abandoned waste sites and 600,000 other sites of land contamination exist in the United States. These estimates exclude soils contaminated with lead paint in older urban areas, the accumulation of fertilizers and pesticides in agricultural land, salination of irrigated soils in arid regions, and other classes of potentially significant soil contamination. Federal and state programs address only some of these sites.

Currently, CERCLA is the EPA's largest program, with expenditures exceeding $3 billion during the 1990s. However, this is only a fraction of the cost to government and industry that will be needed to clean all hazardous and toxic waste sites. Mitigation of the worst 9,000 waste sites is estimated to cost at least $500 billion, and to take at least 50 years to complete. The problem of contaminated soil is significant not only in the United States, but in all industrialized countries.

U.S. laws such as CERCLA and the Resource Conservation and Recovery Act (RCRA) also attempt to prohibit practices that have led to extensive soil contamination in the past. These laws restrict disposal practices, and they mandate financial liability to recover cleanup, personal injury and property damage costs. Furthermore, the laws discourage polluters from willful misconduct or negligence by exposing non-compliant industries and individuals to criminal liability. Pollution prevention regulations also require record keeping to track waste, and provide incentives to reduce waste generation and improve waste management.