Clean Water in the Age of Chemistry

Research and education are key to ensuring healthy aquatic ecosystems and a safe drinking-water supply.

People use a wide variety of chemicals in their everyday lives, including over-the-counter medications, prescription drugs, and personal care products. While these chemical-containing products bring great benefits, they also pose potential threats to ecosystem health.

That's because the chemicals in these products enter wastewater treatment plants, both when they are manufactured and when they are used by consumers. For example, not all of the medicines patients ingest are absorbed by their bodies; some of the active ingredients in these drugs are excreted and enter the wastewater stream. Wastewater treatment plants were not designed to remove these compounds, known as emerging contaminants (ECs), so they are often discharged to surface water bodies, where they have been documented to disrupt the endocrine systems of aquatic organisms and persist in drinking water supplies.

In addition to human sources of ECs, veterinary pharmaceuticals and synthetic hormones given to livestock are inadvertently introduced into the environment when manure is used as a fertilizer source for agricultural fields. During rainfall events, ECs infiltrate into the soil, or become mobilized from fields and transported to receiving water bodies.

Research is still needed to better understand how ECs move through the water cycle. However, sufficient information about the major sources of ECs is known to enable engineering research to begin designing effective treatment technologies. My research group is conducting research on the effectiveness of different manure application methods, such as shallow disk injection, and water reuse systems, such as Penn State's "Living Filter," to reduce the presence of ECs in surface water. Both show promise as effective mitigation techniques over common surface broadcast methods of manure application and discharge of treated wastewater directly to surface water.

Because the risks associated with exposure to ECs are not yet well understood and safe levels remain unclear, regulations for surface water and drinking water have not been established. Fortunately, we do not need to wait for regulations to improve water quality. One of the best ways to reduce the presence of ECs in the environment is to recognize and manage them at their sources rather than treating them once they enter the water cycle. Education and outreach programs are the best chance we currently have to change human behavior and, in turn, reduce the presence of ECs in water.

In an effort to educate the public, my research group has created an online tool that helps members of the public understand their current consumption of products containing ECs so they can make informed choices about how best to reduce their usage of these compounds. The tool can estimate the mass of ECs in the products that people use in their everyday household activities associated with personal hygiene and household cleaning. In addition, we are working with volunteer citizen scientists who are sampling surface water across the Susquehanna River watershed for endocrine-disrupting compounds. They will be engaged in focus group discussions this summer to help set future research directions.

Another public outreach success story is the widespread implementation of unwanted medication collection drives sponsored by municipalities. People are responding positively to these collection drives and are happy to be provided with the opportunity to be good environmental stewards. Returning excess medicine (human and veterinary) through these drives enables ECs that would otherwise enter landfills or wastewater to be disposed of properly and kept out of our environment.

Ultimately, it will take a collective effort to ensure that surface water can continue to support healthy aquatic ecosystems and serve as a safe drinking water supply. Although each individual's actions may seem small, such decisions can influence the behavior of others and serve as the basis for grassroots support for policy changes. It is our goal to provide research that empowers the general public with the information they need to serve as effective environmental stewards. Individually and collectively, we can all strive to ensure the health of our aquatic ecosystems and the long-term sustainability of our water resources.

-- Heather Gall

Heather Gall is an assistant professor of agricultural and biological engineering at Penn State.