Environmental Health - Toxic Substances Hydrology Program

Ecological Effects

Our ability to measure contaminants currently exceeds our understanding of their potential environmental effects.

Fathead minnow in a laboratory aquarium
Adult fathead minnows, such as this one, were exposed to treated wastewater effluent that contained pharmaceuticals to help scientists understand the effects of pharmaceuticals on fish in streams. Photo Credit: Megan Cox, St. Cloud State University.

For most emerging contaminants, there is currently little information regarding their potential toxicological significance in ecosystems -- particularly effects from long-term, low-level environmental exposures. Correlations between occurrence of emerging contaminants in the environment with occurrence in the tissue of aquatic biota are investigated in this project and used where possible in development and testing of hypotheses on biological effects. Evaluating ecological effects of environmental contamination goes beyond observing co-occurrence of contaminants and adverse effects to documenting cause and effect relationships. Research to characterize cause-and-effect relationships requires documentation of contaminant uptake, modes of action, and biological endpoints.

Stacks of experimental fish tanks in side a laboratory trailer
Fish tanks inside an onsite laboratory where fathead minnows were exposed to untreated and treated wastewater for 28 days to test for possible endocrine disruption. A multidisciplinary team of scientists demonstrated that improvements to the treatment process at a wastewater treatment facility (WWTF) reduced the level of endocrine disruption in fish exposed to wastewater effluent discharged from the facility. Photo credit: Alan Vajda, University of Colorado.

Emerging Chemical Contaminants

Emerging Microbial Contaminants

The contamination of the environment with antibiotics and other emerging contaminants may result in changes in the microbial ecology of that environment, possibly changing the types of bacteria that carry out important ecosystem processes such as nutrient transformations and biomass decomposition. In addition, antibiotic-resistant bacteria may survive and transfer their resistance to other bacteria, perhaps resulting in human health effects. This project examines the occurrence of antibiotic-resistant bacteria at beaches, on plant surfaces, and in the soil, and relates findings to environmental conditions, and human activities to better understand the implications of emerging chemical use. Such studies have been conducted in collaboration with the Centers for Disease Control and with local public health departments.

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