drinking water quality

Science Guides Public Health Protection for Drinking Water

By Joel Beauvais

As a country, we’ve come a long way toward providing clean air, water, and land – essential resources that support healthy, productive lives. But we have more work to do to make sure that every American has access to safe drinking water.

That’s why EPA launched a concerted engagement effort with key partners and stakeholders – including state, tribal and local governments, drinking water utilities, and public health, environmental and community stakeholders – to develop and implement a national action plan to address critical drinking water challenges and opportunities.

As always, our work to protect public health and the environment must consistently be built on a foundation of sound science and data. When it comes to drinking water, scientific information helps us identify pollutants of concern – including new or emerging contaminants – assess potential health impacts, and understand the steps needed to address them.

Today, based on the latest science on two chemical contaminants called PFOA and PFOS, EPA released drinking water health advisories to provide the most up-to-date information on the health risks of these chemicals. These advisories will help local water systems and state, tribal and local officials take the appropriate steps to address PFOA and PFOS if needed.

For many years, PFOA and PFOS were widely used in carpets, clothing, furniture fabrics, food packaging, and other materials to make them more resistant to water, grease, and stains. PFOA and PFOS were also used for firefighting at airfields and in a number of industrial processes.  Between 2000 and 2002, PFOS was voluntarily phased out of production in the U.S. by its primary manufacturer. And EPA asked eight major companies to commit to eliminate their production and use of PFOA by the end of 2015 and they have indicated that they have met their commitments. While there are some limited ongoing uses of these chemicals, in recent years, blood testing data has shown that exposures are declining across the country.

For most people, their source of exposure to PFOA and PFOS has come through food and consumer products. But drinking water can be an additional source of exposure in the small percentage of communities where these chemicals have contaminated water supplies.  This is typically a localized issue associated with a specific facility – for example, in communities where a manufacturing plant or airfield made or used these chemicals.

EPA’s assessment indicates that drinking water with individual or combined concentrations of PFOA and PFOS below 70 parts per trillion is not expected to result in adverse health effects over a lifetime of exposure.  These levels reflect a margin of protection, including for the most sensitive populations.

If these chemicals are found in drinking water systems above these levels, system operators should quickly conduct additional sampling to assess the level, scope, and source of contamination.  They should also promptly notify consumers and consult with their state drinking water agency to discuss appropriate next steps. Public notification is especially important for pregnant or nursing women because of the impact these chemicals can have on the development of fetuses and breastfed or formula-fed infants. There are a number of options available to water systems to lower concentrations of these chemicals in the drinking water supply.

EPA will continue sharing the latest science and information so that state and local officials can make informed decisions and take actions to protect public health.  This is an important part of our broader effort to support states and public water systems as we work together to strengthen the safety of America’s drinking water.

For more information on the health advisories for PFOA and PFOS, visit the webpage.

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Digitally Detecting Waterborne Illnesses

By Marguerite Huber

Toxoplasma gondii oocysts

Toxoplasma gondii oocysts

The smaller something is, the harder it is to find. Just try finding a needle in a haystack, or low concentrations of pathogens such as Toxoplasma gondii (T. gondii) and Cryptosporidium in drinking water. These two human pathogens are the leading causes of protozoan waterborne illnesses (toxoplasmosis and cryptosporidiosis), so they are something the drinking water industries are working hard to monitor.

To understand exposure risks associated with T. gondii and Cryptosporidium, sensitive and accurate detection and clinical diagnostic tools must be in place. The lack of such tools make environmental monitoring for these parasites challenging.

One of the biggest issues with monitoring human pathogens is that if it is environmentally transmitted (such as through drinking water), its concentrations can be very low, making it difficult to detect with current water monitoring practices.

EPA researchers have recognized that detection is the biggest challenge. They are working to help bring current methods–which rely on a technique known as polymerase chain reaction (PCR) that amplifies genetic material (DNA) for further analysis—into the digital age. They have designed software to assess the performance and detection limits of digital PCR (dPCR) to accurately quantify low concentration levels of T. gondii and Cryptosporidium.

Dr. Eric Villegas, a scientist working on the project explains, “Digital PCR can perform up to a million reactions in the same amount of time that standard techniques take, improving how we model the detection of waterborne pathogens.”

This capability of dPCR offers a whole new set of opportunities, including greater statistical power to detect if the pathogen is present and, if so, to determine its concentration. “The software that we developed assesses the quality of the data collected and determines the concentration of pathogens with high precision and accuracy,” researcher Dr. Scott Keely, explains. Ultimately, this approach will provide additional sensitivity for quick and accurate diagnosis of parasite infections.

Overall, this research will detect pathogens better and faster than existing methods, which will allow policymakers, drinking water utilities, and managers to scrutinize available data, analyze it with confidence, and learn what type of data to collect in the future. Most importantly, it will help minimize any health risk related to drinking and recreational water quality by providing decision-makers with methods and tools that decrease the amount of time to reach decisions regarding the management of water bodies or other sources of drinking water where these pathogens are of potential concern.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Editor's Note: The opinions expressed herein are those of the author alone. EPA does not verify the accuracy or science of the contents of the blog, nor does EPA endorse the opinions or positions expressed. You may share this post. However, please do not change the title or the content. If you do make changes, please do not attribute the edited title or content to EPA or the author.

EPA's official web site is www.epa.gov. Some links on this page may redirect users from the EPA website to a non-EPA, third-party site. In doing so, EPA is directing you only to the specific content referenced at the time of publication, not to any other content that may appear on the same webpage or elsewhere on the third-party site, or be added at a later date.

EPA is providing this link for informational purposes only. EPA cannot attest to the accuracy of non-EPA information provided by any third-party sites or any other linked site. EPA does not endorse any non-government websites, companies, internet applications or any policies or information expressed therein.