Pharmaceuticals in Drinking Water

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When cleaning out your medicine cabinet, what do you do with your expired pills?  Many people flush them down the toilet or toss them into the trash can.  Although this seems convenient, these simple actions may be contaminating your water supply.

Recent studies are generating a growing concern over pharmaceuticals and other personal care products entering surface and groundwater.  Pharmaceuticals include chemicals such as over the counter medicines, cosmetics and other personal care products, as well as antibiotics and growth hormones used with livestock.

Starting in the mid 1980’s, studies began to sound the alarm.  In the US and in Europe, aspirin, caffeine, nicotine and biproducts of soaps, shampoos and other personal care products were showing up in rivers below waste water treatment plants.  A sampling program in the 1990s found 30 different pharmaceuticals and related chemicals in surface water samples (Ternes, 1998).  More recently a study published by the U.S. Geological Survey found a broad range of chemicals downstream from urban areas.  Of the 95 chemicals the USGS measured, one or more were found in 80 percent of the streams sampled and about one-third of the streams contained 10 or more of the chemicals (USGS 2002).  Recent work by Colorado State University has also found elevated antibiotics in surface water downstream from livestock operations and manure fields (Davis, 2004).  

Are humans or the natural environment affected?

The levels of most of these chemicals measured in streams and groundwater are very low (parts per trillion) and therefore below the prescription dosage.  However, evidence is mounting that these chemicals are finding their way into humans.  For example, one study looking at household and industrial chemicals found that over 80% of American children contained residue of at least one pesticide.  Scientists are concerned that these chemicals may disrupt human hormone systems, cause lower sperm counts, and be linked to increased rates of breast, testicular, and prostate cancer, and increased incidence of hyperactivity.  Antibiotics in our environment create a different type of problem.  Disease causing bacteria exposed to low levels of antibiotics over extended periods of time may lead to resistant strains which cannot be treated easily. 

Around the world, changes in fish, amphibians, and other organisms have been noted.  These range from premature spawning in shellfish to the inability of fish to repair damaged fins (Reynolds 2003).  In all cases, low levels of these chemicals are a prime suspect.  

How do these chemicals get into the water?

Sources of pharmaceuticals and personal care products include pharmaceutical industries, hospitals, medical facilities, households, and agricultural areas.  Many drugs are absorbed by humans and livestock upon consumption, however, certain drugs pass through partially unchanged.  These drugs can enter the environment at higher levels through human and livestock waste.  Improper disposal of unused products is also a factor.  Many of these drugs and care products do not biodegrade and may persist in the groundwater for years.

The amount of these chemicals released into the environment is also a concern.  The amount of personal care products and pharmaceuticals released to the environment is estimated to be about the same as the amount of pesticides used each year.  Furthermore, the U.S. accounts for about half of all pharmaceutical use in the world. 

What can we do?

Unfortunately, clean up and removal of these pollutants is a difficult task.  Wastewater treatment methods used in the U.S. aren’t designed to remove many of these chemicals, and much of the contaminated water is from nonpoint sources and is never treated.  This means that much of what goes down our toilets and our drains finds its way to our streams and groundwater. 

Drinking water treatment plants can remove many of these chemicals, but the technologies that are most effective are not common in the U.S.   The most effective treatment methods include advanced oxidation, membrane filtration, and nano-filtration.  The least effective method is chlorination, which is the most common technique used in the U.S. (Reynolds 2003).  

Prevention is always the best strategy for reducing contamination.   Individuals can minimize overuse and misuse of drugs and properly dispose of medications rather than dump them down a drain.  Industries are working to produce more environmentally friendly chemicals and increase point of use treatment. 

The good news is that the concentrations currently being detected are very low, and there is time to develop new treatments and modify our current practices to protect our waters.  All of these actions to keep drugs and care products from finding their way into your water will ultimately protect you and your family.  

For more information:

Bohlander, B.  2004  Colorado State Study Finds Antibiotics used for Growth, Prevention of Diseases in Food Animals can make their way into Waterways. Press Release. http://www.news.colostate.edu/Release/656

Davis, J.  2004.  Antibiotics in the Environment. From the Ground Up - Agronomy News.  Volume 23, Issue 3.

Gujarathi and Linden.  2004.  Antibiotics in the Environment.  From the Ground Up – Agronomy News. Volume 24, Issue 3. http://www.extsoilcrop.colostate.edu/Newsletters/documents/2004_antibiotics.pdf

Jobling et al.  1996.  Inhibition of Testicular Growth in Rainbow Trout (Oncorhhynchus Mykiss) exposed to Estrogenic Alkylphenolic Chemicals.  Journal of Environmental Toxicology and Chemistry. Volume 15, Issue 2 :  194-202.

Reynolds, K. 2003.  Pharmaceuticals in Drinking Water Supplies.  Water Conditioning and Purification Magazine  Volume 45, Number 6. http://www.wcponline.com/NewsView.cfm?ID=2199

Ternes, TA.  1998.  Occurrence of drugs in German sewage treatment plants and rivers.  Water Research 32  (11):  3245-3260.

USGS, 2002.  Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in US Streams. USGS Fact Sheet FS-027-02 (PDF [372k]) http://toxics.usgs.gov/pubs/FS-027-02/