Landfills

Landfills present long-term threats to groundwater and surface waters that are hydrologically connected by creating a toxic soup of industrial and home-cleaning chemicals. Containing everything from industrial solvents to household cleaners, landfill chemicals accumulate and mix over time with precipitation that falls into a landfill, which results in the extraction of the water-soluble compounds and particulate matter of the waste. This leads to the subsequent formation of leachate, also known as "garbage soup", which is a highly toxic liquid formed when waste breaks down in the landfill and water filters through that waste, which can pollute the land, ground water and water ways, presenting a major threat to the current and future quality of groundwater. Furthermore, electronic waste, which contains everything from lead to cadmium, is also a large contributor to water quality issues near landfills. The EPA reports that in 2009, of the 2.37 million short tons of electronic waste, around 25 percent or less were recycled. These chemicals accumulate and are washed away periodically by rain, potentially dragging them toward municipal water supplies. The release of hazardous and nonhazardous components of leachate may present a danger to the environment and to aquatic species or other wildlife if the leachate-contaminated groundwater plume discharges to wetlands or streams and may render an aquifer unusable for drinking-water purposes and other uses. Although many landfills are now constructed with liners that contain leachate and leachate collection systems that collect it, historically, many landfills were constructed without liners or leachate collection systems. It is widely recognized that even the best-installed plastic liner will succumb to deterioration over time and will eventually allow leachate to be created and released. Postclosure groundwater monitoring at landfill sites are required for 30 years, however, the deterioration of landfill liners may not be detected or occur during the time the landfill operators are actively involved and financially obligated. Learn more.

"Liner hazards depend on the type of liner used in a landfill. Clay liners are susceptible to fractures and cracking, allowing leachate to leak out. Diffusion can also allow organic compounds such as benzene to leach through 3 inches of clay in about five years. Other chemicals can cause the clay liner to degrade. Plastic liners made from high-density polyethylene can become compromised by several household chemicals and other products, allowing leaks to form. Composite liners combine both liner types. However, they will still eventually develop leaks. An average 10-acre landfill will have a leak rate of between 0.2 and 10 gallons a day." ~ eHow: Harmful Effects of Landfills (original source)