Environmental researchers at Auburn University investigate micropollutants in estuaries

Estuarine core samples

As more and more people choose to live near the water, the world’s estuaries are increasingly impacted by chemical compounds from the land. Researchers from Auburn University’s Estuarine Environments Research Program, led by the environmental engineering group in the Department of Civil Engineering, are investigating the behavior and fate of these compounds, and the threat they may pose to aquatic organisms living in estuaries.

Estuaries are partially enclosed bodies of water along the coast where freshwater from rivers and streams mix with salt water from the ocean. Estuarine environments have evolved to produce unique and diverse communities of plants and animals. More than half of the world’s population lives or works adjacent to estuaries, a proximity that creates increased risks to estuarine organisms.

The EERP researchers use a variety of sampling tools to collect sediment and water samples from nearshore coastal and estuarine waters along the Gulf Coast. These tools include a 34-foot tri-pontoon boat with a custom-designed vibracore system to collect long sediment cores (4-inch diameter, up to 6-foot length), and a 21-foot shallow water research vessel for water and sediment sampling in shallow estuarine waters.

In an advanced analytical chemistry laboratory designed specifically for Auburn’s EERP program, the team examines samples for known or suspected endocrine disrupting chemicals, which are predominantly synthetic organic compounds used in a variety of industrial, agricultural, household and pharmaceutic products. Laboratory instrumentation includes a state-of-the-art Agilent Technologies triple quadrupole liquid chromatography/mass spectrometer, allowing for quantitative analysis of environmental samples having trace amounts of endocrine disrupting compounds.

This analytical capability is critical, since trace amounts of these compounds can inhibit the reproductive processes, development, gender distributions and immune functions in estuarine aquatic organisms by disrupting endocrine biochemistry. As one example, endocrine disrupting compounds mimicking the natural hormone estradiol have been shown to cause long-term and transgenerational changes in oyster gender distributions .

“Endocrine disrupting chemicals can flow into estuarine systems in a variety of ways, including stormwater runoff and through water treatment systems,” explains Joel Hayworth, associate professor of civil engineering and a principal investigator of the project. “Micropollutants exist in systems in very low concentrations and are almost impossible to detect or remove by conventional water and wastewater treatment methods. Nevertheless, they often have profound and lasting effects on sensitive estuarine organisms.”

Hayworth said the team looks to better understand the physical and chemical behavior of endocrine disrupting compounds in Gulf Coast estuarine systems, with the ultimate goal of developing methods for predicting the fate of endocrine disruptors from their introduction into coastal estuarine systems to their sequestration or removal from these systems. In the coming years, the team will expand their investigations to estuaries on the eastern and western coasts of the United States, as well as to other estuaries worldwide.

In addition to Hayworth, the research team includes civil engineering faculty members Mark Barnett, professor; Xing Fang, Arthur H. Feagin professor; Jose Vasconcelos, assistant professor; Vanisree Mulabagal, research fellow; and several undergraduate and graduate students.