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Tuesday, January 30 • 4:20pm - 4:40pm
SYMPOSIA-11: Biological Effects of Septic Seepage on Resident Fish Species in Minnesota Lakes

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AUTHORS. Les D. Warren, St. Cloud State University; Meaghan Guyader, Colorado School of Mines; Christopher Higgins, Colorado School of Mines; Heiko Schoenfuss, St. Cloud State University

ABSTRACT. The potential for on-site wastewater treatment systems (“septic systems”) to represent non-point source of contaminants into lakes is a growing concern. Many lakes are down-gradient from septic systems, and their seepage may infiltrate shallow groundwater and enters the shallows of adjacent lakes though hydrological processes. Five study lakes were established, each with septic-influenced and reference sites. Water sampling throughout the early spring and summer established the presence and absence of contaminants at each site. Adult male sunfish were collected off of their spawning beds between May and July to assess contaminant related endpoints included histopathology of gonad, liver, and gill tissues, and analysis of vitellogenin, estradiol, and 11-keto testosterone in plasma samples. Elevated vitellogenin levels (p = 0.01, t-test) and a reduction in liver size (p = 0.01, t-test) were observed in resident males from septic-influenced sites. Our results provide a direct link between septic system seepage and biological effects. The assessment of biological endpoints in sunfish and laboratory exposed fathead minnows provides a rich data matrix to support that contaminants from septic seepage cause adverse health effects in resident fish populations in northern lakes.

Tuesday January 30, 2018 4:20pm - 4:40pm CST