Long-Term Effects of an Abandoned Leaching Septic Tank

Septic tanks are often used for the treatment of human waste in rural areas that lack sewage treatment facilities. Abandoned or leaking tanks pose risks to human health as well as to the environment. Septic tanks can leach contaminants into groundwater and release noxious greenhouse gases into the atmosphere if they do not receive proper maintenance.

Nitrogenous Compounds

• The decomposition of organic material -- such as human waste -- forms compounds containing nitrogen as byproducts. Nitrogenous compounds in water have been associated with decreased immune function, lower reproductive rates and manipulation of hormones. A study published in the July 2002 issue of the "Journal of Environmental Quality" investigated the accumulation of nitrogen in water supplies in Florida. The authors found that up to 60 percent of the nitrogen in septic tanks will leach into the water table. The study also found that fecal organisms, such as enteric viruses, were also detected in groundwater and soil samples from septic tanks.

Release of Greenhouse Gases

• Septic tanks store waste materials and their breakdown releases greenhouse gases into the air including methane, carbon dioxide and nitric oxide. An article appearing in the April 2011 issue of "Environmental Science and Technology" estimated the amounts of these compounds released from septic tanks. The authors determined emission rates of gases from septic tanks and found that they were a significant source of greenhouse gas pollution due to the number of tanks currently in use.

Pollution of Coastal Waters

• The island of Bermuda has no sewage system and its residents rely upon septic tanks to dispose of waste. An article published in the October 2010 issue of "Environmental Monitoring and Assessment" measured the concentrations of enterococci, bacteria that inhabit the intestinal tract, in surface waters around the island over a five year period. The researchers monitored 30 sites and classified eight of them as either "sufficient" or "poor" based on the European Union Water Directive guidelines. The study also found that 20 to 30 percent of water samples collected from creeks and bays tested positive for enterococci contamination.

Groundwater Contamination

• Rural cities heavily rely on septic tanks for the disposal of human waste. A study in the June 2011 issue of "Environmental Monitoring and Assessment" evaluated the quality of groundwater in rural Puri City, India. The researchers gathered groundwater samples and evaluated them according to guidelines set by the Bureau of Indian Standards and Environmental Protection Agency. The study found that the quality of ground water was compromised by the use of septic tanks leaching waste products. The study concluded by suggesting measures to prevent further groundwater contamination.