Studying Geology and Water Chemistry in the Delaware River Basin

Water quality is just one of the many important pieces of the puzzle that makes up environmental, ecological and human health. The Patrick Center for Environmental Research at the Academy of Natural Sciences strives to understand and protect watersheds in this changing world, so in partnership with organizations of the Delaware River Watershed Initiative, water quality monitoring efforts and studies are being conducted in the Delaware River Basin.

Many Drexel University students are involved in a myriad of projects coming out of the Academy. We reached out to recently graduated Biodiversity, Earth and Environmental Science alum Kayla Aughenbaugh to learn more about her biogeochemistry work in the Patrick Center.

Drexel Geoscience Student, Kayla Aughenbaugh, collecting fossils on a field trip.

Tell us more about yourself.

I recently graduated from the Geoscience Undergraduate Program at Drexel University. My main interest was the role that chemical processes play in the Earth’s systems. The opportunity to collaborate with scientists at the Academy and get hands-on experiences in the lab and field solidified my passion for the influence of chemistry on the geosphere. I am currently pursuing a master’s degree following my graduation from Drexel focused on igneous petrology and geochemistry.

How did you begin conducting research at the Academy of Natural Sciences?

Last year I took a geochemistry course with the Academy’s Post-Doctoral Researcher and Stable Isotope Analyst Michelle Gannon, PhD. A couple of weeks into the term, she helped me to get involved with the Biogeochemistry Section of the Patrick Center. I began volunteering as a research assistant where I collected samples and field data of surface water and performed geochemical analyses. My efforts contributed to a surplus of local studies and monitoring projects in the Delaware River Basin area.

While working in the lab was tremendously beneficial to my development as a scientist, I wanted to learn more about the projects going on within the research group. This curiosity influenced me to pursue additional research.

The Delaware River, as seen from Mount Tammany in Northern New Jersey.

What did your research entail?

In January 2022, I began work on an independent project advised by Senior Scientist David Velinsky, PhD, and Dr. Gannon to address a knowledge gap: the influence of local geology and bedrock composition on surface water chemistry across the Delaware River Basin. In other words, I am concerned with how carbonate-bearing bedrock, such as limestone, might contribute calcium and magnesium ions to this watershed — these particular ions contribute to the overall hardness of water. Understanding the concentrations of these ions in water is important, especially from a residential standpoint, as they can build up in the pipes in your home and can make soap less effective.

I conducted a preliminary study where I analyzed data spanning years 2013 to 2021 collected from the DRWI database at just four sites with varying bedrock composition. My findings conclude that the sites with underlying carbonate-bearing bedrock consequently had harder water, or water with larger concentrations of calcium and magnesium ions.

I continued to develop this project for my undergraduate thesis in which I investigated these interactions at a larger scale across the Basin. This included analyzing data at 35 different site locations spanning New York, New Jersey and Pennsylvania.

What were the results of your research?

My research shows that sites with carbonate-bearing bedrock tend to have correspondingly harder water. However, I have found that the sites nearest Philadelphia show results that stray from my hypothesis. These four sites overlie bedrock that does not contain any hardness contributing minerals, so, I predicted the water hardness to be low. But these sites have hardness concentrations comparable to carbonate-containing sites.

What I predict we might be seeing here is actually large amounts of calcium contributing to the total hardness that is not of carbonate-bedrock origin. Instead, this calcium may be coming from industrial applications, such as concrete use in buildings or sidewalks or the salts applied to road surfaces in the winter months. The chloride concentrations at these sites are among the highest in the database. I hope to explore the connection between industrial activity near Philadelphia in relation to water hardness in the future.

What is the importance of the type of work you are conducting?

It is extremely important to understand how different aspects, such as land usage, geology, industry and climate, all contribute to water quality. This research provides a more comprehensive model of surface water chemistry in the Delaware River Basin, the very watershed where Philadelphia’s drinking water is sourced. My findings related to the very hard water at the DRWI sites near Philadelphia present potentially interesting future implications for research focused on the long-term impact of industrial activity in urban landscapes of surface water chemistry and quality.

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