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K-State Today

November 2, 2017

Division of Biology welcomes seminar speaker Melody Bernot Nov. 3

Submitted by Division of Biology

Melody Bernot, Ball State University, will present "Trace organic contaminants (TOCs) in freshwater ecosystems: Abundance, fate and effects" as part of the Division of Biology seminar series at 4 p.m. Friday, Nov. 3, in 221 Ackert Hall.

Trace organic contaminants enter freshwater ecosystems via multiple sources including disposal of surplus drugs, human excretion into sewage, and runoff associated with therapeutic treatment of livestock. Bernot has measured trace organic contaminant abundance in U.S. freshwaters since 2008 to assess factors controlling abundance and distribution of these contaminants. Significant differences in trace organic contaminant compounds detected and concentrations measured have been identified both among sites — spatial variation — and within sites — temporal variation. Trace organic contaminants detected in more than 60 percent of samples include acetaminophen, 2.1-460 ng/L; carbamazepine, 1.1-2.7 ng/L; caffeine, 11-400 ng/L; cotinine, 2.1-12 ng/L; DEET, 23-150 ng/L; gemfibrozil, 1.2-4.9 ng/L; ibuprofen, 1.8-42 ng/L; sulfamethoxazole, 1.4-15 ng/L; sulfamethazine, 1.8 ng/L; triclosan, 9.1-22 ng/L; and trimethoprim, 3-9.7 ng/L. Across sites, water column dissolved oxygen and temperature correlates with pharmaceutical abundance suggesting the potential for microbial degradation is important to persistence of these emerging contaminants in freshwaters. Overall, trace organic contaminant concentrations are highest in winter when irradiation and temperature are lower. Laboratory experiments show trace organic contaminants significantly alter microbial activity — as respiration and nutrient uptake — and invertebrate and vertebrate activity — as growth, reproduction and behavior — even at the trace concentrations measured in freshwaters. A more comprehensive understanding of spatial and temporal variability of these contaminants is needed to mitigate potential adverse effects and assess regulatory need.

If you would like to visit with Bernot, contact Walter Dodds at wkdodds@k-state.edu