Understanding Sources of Aquatic Contaminants of Emerging Concern

Pharmaceuticals, hormones, and other contaminants of emerging concern (CECs) are found in surface waters in Minnesota and nationally. CECs can cause adverse ecological and human health impacts, and occur as complex mixtures in the environment. One of the greatest barriers to addressing the problem of CECs is a lack of understanding of where these compounds come from and which sources dominate in different locations and at different times.

We hypothesize that different land uses result in the presence of unique marker compounds, relative concentrations of compounds, and temporal occurrence patterns that will differentiate agricultural sources (crop and livestock production) from non-agricultural sources (residential septic, wastewater treatment effluent). These markers can be used to determine the comparative load of CECs to water, which can in turn be used to help policy-makers and stakeholders develop strategies to reduce their occurrence. The Zumbro River watershed in southeastern Minnesota provides a unique opportunity to study CECs because each of its sub-watersheds has a single dominant land use. We will use field data collected from each sub-watershed to develop a suite of markers for source discrimination and load determination. Ultimately, this “source signature” will be applied to other water bodies in the state for similar source characterization.

This project will address three major objectives:
- Determine what CECs are associated with specific land-uses
- Identify indicator compounds to be used as a monitoring tool to determine sources and loads of CECs
- Work with policy-makers to develop science-based recommendations for prevention, reduction, and remediation strategies