Health Impacts

Many communities are faced with CSO and SSO impacts. Although CMAP does not have specific epidemiological data that provides examples of negative health impacts as a result of wastewater treatment plant discharges, the USEPA has reported that untreated sewage from these sources can "contaminate our waters, causing serious water quality problems and threaten drinking water supplies" (USEPA 2001, 2). Both combined sewer overflows and sanitary sewer overflows carry "bacteria, viruses, protozoa"[1] and many other diseases (USEPA 2001).

Combined sewer systems carry a combination of sanitary sewage and stormwater runoff in a single pipe for treatment at the WWTFs; however, during wet weather events, the hydraulic capacity of the pipes and wastewater treatment facility can be overloaded, causing these systems to discharge untreated wastewater and contaminated stormwater directly into receiving waters. This overflow may or may not be disinfected (chlorinated) before being discharged into drinking water supplies for downstream communities. Some examples of CSO occurrences include the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) which reported overflows (CSOs) once every 7.44 days on average in 2007. In an effort to abate these occurrences, the MWRDGC has undertaken a Tunnel and Reservoir Plan (TARP), also known as the Deep Tunnel system, to "capture and store combined sewer overflow until it can be pumped to existing plants for treatment and released to local waterways" [2] (Landis 2008, 15). To further address this problem, the USEPA adopted a CSO Control Policy in 1997. This Policy includes Nine Minimum Controls, including public notification by the wastewater treatment plant whenever there is an overflow event (EPA 1995).

Sanitary Sewer Overflows are the result of an "unintentional release of sewage from a collection system before it reaches the treatment plant" (USEPA, Office of Water). SSOs are often caused by aging infrastructure and can result in the discharge of raw sewage into surface waters or groundwater. SSOs, like CSOs, can cause adverse water quality impacts and threaten drinking water supplies. In addition, SSOs can have negative impacts on both public and private property when sewage backs up into nearby households. On average, "homeowners and/or sewer authorities have incurred cleanup and repair costs that typically can range between $700 and $4,000 per home for damages that are rarely covered by insurance." (USEPA, Office of Water)

Recently, researchers have focused their attention on Endocrine Disrupting Compounds (EDC).[3] While toxicologists have determined that EDCs are capable of and have had detrimental effects on wildlife, their effects on humans are still controversial.[4] Exposure to contaminants through direct contact or through drinking contaminated water can have serious health consequences. Such exposure can occur in areas of high public access, basements, lawns, streets or waterbodies used for public recreation.

Effective wastewater planning can reduce EDC contamination that can adversely affect wildlife and public health impacts. As treatment plants plan for capital replacement they should consider technologies that are more effective at treating EDCs such as ozonation, ultraviolet advanced oxidation, and activated carbon (Bolles, 2008). Municipalities, that are generally designated management agencies of wastewater treatment plants, can also educate their residents on pesticide and herbicide use and medication disposal when doing wastewater planning. Municipalities and townships can establish medication collection programs to reduce the amount of EDCs discharged to sewage treatment plants, and ultimately released into our waterways.

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[1] USEPA Source Water Protection Practices Bulletin.

[2] To date, the Deep Tunnel project has captured and treated "more than 950 billion gal of CSOs" which would have otherwise "overflowed into area waterways." Though construction of the entire TARP is still underway, potential negative impacts to public and private property has been realized. It is evident that water quality has also improved as a result of the project since "rivers are once again abundant with many species of aquatic life, and riverfronts have been reclaimed as natural resources for recreation and development" (Landis 2008, 17).

[3] The USEPA has identified EDCs as exogenous agents that interfere with the synthesis, secretion, transport, binding action or elimination of natural hormones in the body that are responsible for the maintenance of homeostasis, reproduction, development and/or behavior. Cited in: Lanyon, Richard. Transmittal Letter for Board Meeting. "Agenda Summary: Endocrine Disrupting Compounds, Antibiotics, and Other Pharmaceuticals in the Water Environment." Metropolitan Water Reclamation District of Greater Chicago. April 7, 2006. EDCs include steroid compounds, surfactants, pesticides, herbicides, fungicides, polyaromatic compounds (such as PCBs) and organic oxygen compounds.

[4] The federal government has recommended EDC concentrations, which should be addressed in a proactive manner.