Man-made Pollutants Finding Their Way Into Groundwater Through Septic Systems

Tuesday, February 10, 2015 - 11:45am

Posted: 10 Feb 2015 06:43 AM PST

Summary: Pharmaceuticals,
hormones and personal care products associated with everyday household
activities are finding their way into groundwater through septic systems in New
York and New England, according to the U.S. Geological Survey


Patrick J.
( Phone: 518-285-5667 ); Irene J.  Fisher ( Phone:
631-736-0783x117 ); Hannah Hamilton
( Phone: 703-648-4356 );



TROY, NY. -- Pharmaceuticals, hormones and personal care
products associated with everyday household activities are finding their way
into groundwater through septic systems in New York and New England, according
to the U.S. Geological Survey.    

“Septic systems nationwide are
receiving increased attention as environmental sources of chemical
contamination,” said USGS scientist Patrick Phillips, lead author of the study
published in the journal Science
of the Total Environment

Two different well networks were
studied, one in New England and the other in New York, looking for
micropollutants in groundwater samples collected downgradient of septic
systems.  “Downgradient” is the term used for how groundwater flows under
the ground, and is a similar term to “downstream” when describing surface
water. The scientists tested for items such as pharmaceuticals, personal care
products, and plasticizer compounds (which make things more flexible).

“High nitrate concentrations in
groundwater samples downgradient of septic systems in both these regions led us
to investigate what other chemicals might also be present,” said Phillips.

Septic systems are common in areas
lacking connection to larger scale sewage treatment, such as a sewer. 
Septic systems consist of holding tank (usually below ground) where raw sewage
collects and separates into a sludge (solid) and liquid effluent.  The
liquid effluent either leaches directly into the surrounding soil or goes into
a leach field for final treatment by the soil. The liquid effluent from septic
systems ultimately moves into the groundwater.

Septic systems have been identified as
the source of a variety of micropollutants in groundwater.  In New York,
groundwater samples were collected from a barrier island with a dense (5
dwellings/acre) summer population.  These New York septic systems have
minimal treatment of wastewater before mixing with shallow groundwater that
moves towards a large, sensitive estuary where a decline in fisheries and
shellfish along with a higher ratio of female-to-male fish have been
reported.  Shallow groundwater samples collected along the beach of this
estuary downgradient of the septic systems were found to have hormones;
detergent degradation products; galaxolide, a fragrance found in various products;
insect repellent; sunscreen additives; floor cleaner; and two pharmaceuticals
(lidocaine, a local anesthetic; and carbamazepine, an anti-convulsant and mood
stabilizing drug).

In New England, groundwater samples
were collected from below a septic system leachbed   serving an
elderly-care 65-bed nursing home and from wells downgradient of this
leachbed.  Numerous prescription pharmaceuticals were found in the
groundwater samples, such as anesthetics; a muscle relaxant; an antifungal; an
antiepileptic; an antibiotic; a sleep aid; and also a floor cleaner. 

Natural groundwater flow in this area
could transport these contaminants toward areas used for a drinking water

Results from both groundwater networks
indicate that septic systems are sources for a variety of micropollutants to
groundwater and surface water that potentially affect environmental ecosystems
and even drinking water.  Land-use, in particular, is one of the deciding
factors that control the type of contaminants entering the groundwater
system.  This study found that monitoring for micropollutants, such as
pharmaceuticals, hormones, and personal care products in areas experiencing
high nitrogen levels was important to understanding the breadth of contaminants
present in groundwater and surface-water resources. 

This study also presents some of the
first results from a new pharmaceutical method developed by the USGS National
Water Quality Laboratory that determines more than 100 pharmaceuticals,
pharmaceutical degradates and related contaminants.  This method is highly
sensitive, with method detection limits for many compounds in the low
nanogram-per-liter range, and significantly advances the abilities of the USGS
to assess the presence and concentrations of pharmaceuticals in the environment.

The paper, “Concentrations
of hormones, pharmaceuticals and other micropollutants in groundwater affected
by septic systems in New England and New York
” has been published
in Science of the Total
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