41 GROUND WATER CONTAMINATION Alabama enjoys an abundant of contaminated ground water is supply of ground water that, if usually expensive, and sometimes a managed wisely, will help fulfill our contaminated water supply must be need for clean water indefinitely. As abandoned and a new supply located. citizens, we should be aware of Preventing contamination before it potential threats to our ground water occurs is the best solution. Because supplies and help to protect those ground water contamination can have supplies from contamination. such serious consequences, many Contaminated ground water may be citizens, as well as local, state, and unfit for certain uses and may federal agencies, are taking action to become harmful to humans, animals, protect ground water resources. vegetation, and property. Treatment Installation of liner in hazardous waste storage pit. 42 POTENTIAL CONTAMINANT SOURCES Common sources of anthro- tanks (UST’s), septic systems, pogenic contaminants include septic pesticides, and nitrates. The Alabama tanks and privies; underground Department of Environmental storage tanks; areas where fertilizer, Management (ADEM) considers pesticides, or herbicides are used or UST’s and failing septic systems to stored; landfills; and unauthorized be the most serious threats to ground dump sites. A more complete list of water in Alabama, because they are potential sources of ground water so numerous. Other sources of contamination is shown in Table 1. potential ground water contamination include unauthorized hazardous The most common sources of waste disposal sites, old landfills, ground water contamination unauthorized dumps, and abandoned nationwide are underground storage wells. Common products which can contaminate ground water 43 Applied correctly, pesticides and fertilizer have minimal impact on ground water quality. Ground water contamination aluminum, selenium, and arsenic, as occurs when ground water comes in well as petroleum, microorganisms, contact with naturally occurring and brine (salty water). contaminants or with contaminants Contaminants associated with human introduced into the environment by activity most commonly include anthropogenic activities. Naturally bacteria, petroleum products, natural occurring substances found locally in and synthetic organic compounds, soil and rocks that can affect ground fertilizer, pesticides, herbicides, and water include lead, iron, manganese, metals. One gallon of gasoline can render more than one million gallons of water unfit to drink! 44 45 Table 1. Potential Sources of Ground Water Contamination (Based upon lists compiled by EPA and ADEM) 1. Improperly functioning septic tanks 36. Heat treaters/smelters/descalers 2. Gas stations/service stations 37. Wood preservers 3. Dry cleaners 38. Chemical reclamation sites 4. Agricultural chemicals, fertilizer, 39. Boat builders/refinishers and pesticides spreading/spraying 40. Industrial waste disposal sites 5. Truck terminals 41. Wastewater impoundment areas 6. Fuel oil distributors/storage 42. Municipal wastewater treatment 7. Oil pipelines plants and land application areas 8. Auto repair shops 43. Landfills/dumps/transfer stations 9. Body shops 44. Junk/salvage yards 10. Rustproofers 45. Subdivisions 11. Auto chemical suppliers/ 46. Individual residences wholesalers/retailers 47. Heating oil storage(consumptive 12. Pesticide/herbicide/insecticide use) sites wholesalers/retailers 48. Golf courses/parks/nurseries 13. Small engine repair shops 49. Sand and gravel mining/other 14. Furniture strippers mining 15. Painters/finishers 50. Abandoned wells 16. Photographic processors 51. Manure piles/other animal waste 17. Printers 52. Feedlots 18. Car Washes 53. Agricultural chemical storage sites 19. Laundromats 54. Construction sites 20. Beauty salons 55. Transportation corridors 21. Medical/dental/veterinarian offices 56. Fertilized fields/agricultural areas 22. Research laboratories 57. Petroleum tank farms 23. Food processors 58. Existing wells 24. Meat packers/slaughterhouses 59. Nonagricultural applicator sites 25. Concrete/asphalt/tar/coal 60. Sinkholes companies 61. Recharge areas of shallow and 26. Treatment plant lagoons highly permeable aquifers 27. Railroad yards 62. Injection wells 28. Stormwater impoundments 63. Drainage wells 29. Cemeteries 64. Waste piles 30. Airport maintenance shops 65. Materials stockpiles 31. Airport fueling areas 66. Animal burial sites 32. Airport firefighter training areas 67. Open burning sites 33. Industrial manufacturers 68. Radioactive disposal sites 34. Machine shops 69. Salt-water intrusion 35. Metal platers 70. Mines and mine tailings 46 UNDERGROUND STORAGE TANKS UST’s are commonly used at by leaking UST’s at about 9,000 sites service stations, refineries, and other in Alabama. Cleanups have been industrial sites where gasoline, fuel completed at about 75 percent of oil, and other chemicals are used. If these sites. Cleanup is continuing at these tanks develop leaks, ground approximately 1500 more locations. water supplies can be seriously Sometimes owners cannot be found contaminated. Between 5 million and or do not have the money to clean 6 million UST’s exist nationwide. up these sites. EPA and ADEM are About 17,000 inventoried UST’s are requiring new UST systems to meet currently in use in Alabama at about standards that should sharply reduce 6,000 locations. To date, soil or the incidence of new leaks and aid in ground water has been contaminated detecting leaks quickly when they do occur. Testing an underground storage tank for leaks. Leaking underground storage tanks have caused more than 90 percent of soil and water contamination in Alabama, but 75 percent of known releases have been cleaned up. 47 Leaking underground storage tanks are the leading cause of ground water contamination in Alabama. Underground storage tanks must meet standards to prevent and detect leaks and spills. 48 SEPTIC SYSTEMS Septic systems are the most materials settle out and are digested common on-site domestic waste by bacteria. The solids must be disposal systems in use. It is periodically cleaned from the tank to estimated that more than 670,000 prevent blockage of field lines and active septic systems exist in subsequent overflow. Liquid waste Alabama, along with an unknown passes from the septic tank into the number of older, abandoned field lines, where it percolates down systems. More than 20,000 new through the soil. Breakdown of these systems are permitted annually. If wastes is accomplished before the properly installed, used, and wastes reach the water table by maintained, septic systems pose no bacterial action in the septic system threat to water quality; however, the and the soil and by the filtering effect Alabama Department of Public of the soil. Introducing hazardous Health estimates that as many as 25 household wastes, including oil, percent of all septic systems in powerful cleaners, and other Alabama could be failing. Every substances into the septic system septic system that malfunctions is a may kill the bacteria in the septic potential source of ground water system and impair the system’s contamination and can have efficiency. Septic systems do not work consequences that extend beyond well in some parts of the state, such the boundaries of the owner’s as the coastal areas because soil property. conditions there are unfavorable. To provide adequate filtering of liquid Properly functioning septic wastes, septic systems require a fairly systems are a simple and effective thick and moderately permeable way to manage household waste. The unsaturated zone. In some locations, waste first enters a tank where solid soils may be thin and the underlying 49 rock, for the most part, impermeable. the shallow aquifer, which could Near the coast, the sandy soils may threaten the homeowner’s own well. be too permeable to properly filter If contaminated wastewater from a out contaminants or the water table malfunctioning septic system may be too near the land surface to saturates soils this could also result allow for proper operation. If a septic in a surface discharge that could be system ceases to function correctly, a health hazard and would not be contaminated wastewater may enter allowable under state law. If a septic tank is well designed and functioning properly, contaminants are removed before reaching the water table. 50 Contamination from a malfunctioning septic system. This household is in danger from a contaminated water supply. 51 PESTICIDES Pesticides are common ground abandoned or improperly sealed water contaminants. About 3.8 wells and sinkholes are more likely. million pounds of solid pesticides and 450,000 gallons of liquid pesticides The presence of trace quantities are applied in Alabama each year to of pesticides in drinking water is not kill insects, rodents, mold, and uncommon, but instances where weeds. Some pesticides are now concentrations exceed permitted prohibited by EPA because they levels are rare. Nationwide, about 10 were contaminating surface and percent of public water supply wells ground water. Others are being contain detectable amounts of studied to pesticides, but determine less than 1 how their use percent should be contain restricted. quantities sufficient to Most constitute a modern public health pesticides risk. Where when used this occurs the properly water must be degrade treated to naturally with Agricultural Spraying Utilizing remove time and Aerial Application contaminats generally do not pose long term before being provided to the public.