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Due to an increased focus from United States Environmental Protection Agency on reducing mercury, the Indiana Department of Environmental Management has been working with wastewater treatment plants to increase awareness of potential mercury sources in Indiana communities.

IDEM is working with publicly owned treatment works (POTW) to encourage practices that reduce the amount of mercury released down the drain by local business and industry.

Why the concern?

Mercury is Toxic:

Although mercury performs many useful functions, it is toxic and can impair the way we see, hear and function.

In the environment, a percentage of mercury undergoes a biological/chemical process and is converted to methylmercury, which is a more toxic form of mercury.

Mercury poisoning can attack the central nervous system in humans. Women of child-bearing age and children, especially those under the age of six, are most susceptible to mercury poisoning.

Stricter Regulation:

Wastewater treatment plants are facing increased regulatory attention for levels of mercury in the wastewater they treat and ultimately discharge into Indiana waters. As a result, treatment plants throughout the state need the cooperation of business, industry and citizens to minimize the amount of mercury escaping down the drain.

Partnering With Your Community

Through a federal grant to IDEM, educational outreach materials were developed for sectors that commonly use mercury at their facility and risk releasing it to the POTW.

The materials were designed to provide a POTW with technical expertise in pollution prevention and source reduction opportunities so they may effectively assist their local community and the sources they regulate to reduce the quantities of mercury discharged or emitted to the water.

Educational mercury outreach materials are available for the following sectors: dentists, colleges and universities, health care facilities and general industry. Materials include a template outreach letter, checklists, fact sheets, and other support information. IDEM mercury outreach materials are also available for hospitals; citizens; schools; the Heating Ventilation Air Conditioning and refrigeration industry and the automotive industry.

Where might mercury be found at the POTW?

Mercury may be found throughout a POTW in products such as batteries; chemical compounds; cleaning agents; laboratory reagents; fluorescent light bulbs; and switches, relays and sensors.

Mercury may also be found in sewer pipes. Mercury can settle at a low point such as in a sump or trap and remain in the pipes of a facility for many years. Often the slow dissolution of mercury in a sump, trap or pipe is enough to cause exceedance of mercury limits in wastewater even after best management practices are implemented. Hot spots in a facility's piping may appear where laboratories or equipment maintenance areas were located. Whenever traps or sumps are moved or cleaned, the solid contents should be treated as a hazardous waste unless proven otherwise.

What can POTWs do to help?

  • Complete a mercury inventory of your facility by using the Mercury Checklist [DOC];
  • Educate your local businesses and community on methods to reduce mercury discharges;
  • Phase out mercury-containing products, when possible;
  • Substitute mercury-free batteries for mercuric oxide (mercury-zinc) batteries;
  • Use safe, non-mercury cleaners and degreasers in labs, housekeeping departments and maintenance areas;
  • Replace mercury-containing thermostats and switches with mercury-free alternatives when remodeling or replacing old equipment;
  • Purchase septic tank and sump pumps that contain magnetic dry reed switches, optic sensors or mechanical switches instead of mercury tilt switches;
  • Examine use of other mercury-containing products in your facility, including generators, high intensity lamps and manometers and consider switching to mercury-free alternatives; and
  • Implement a mercury-free purchasing policy.

Other Resources

For additional information call (800) 988-7901 or (317) 232-8172

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