Temporal Distribution of Cyanotoxins and Environmental Estrogens within the Upper and Middle Potomac River Drainage, USA

Track 3C: Gaining Insights from Vertebrate Organisms
Thursday, October 12, 2017, 3:40 pm – 5:10 pm

Ryan P. Braham
West Virginia University U.S Geological Survey Leetown Science Center

Significant fish die-offs across taxa were observed in the Potomac River basin in 2002 and 2005 and continued sporadic mortalities of varying intensity have been observed since then. An intensive investigation yielded multiple stressors; however no definitive driver. Harmful algae blooms were first quantified in the lower Potomac River in 1983 with sporadic reports going back to 1930. The specific cause of these and subsequent blooms remain unclear; however it is believed to be partially driven by low water years. Environmental estrogens (EE) have also been observed in the Potomac River drainage in recent years and are believed to play a role in the occurance of endocrine disruption in fishes. Our research objective was to quantify microcystin (MC) toxins and EE throughout the Potomac River drainage. Significant spikes were observed between June and September for total MC and total estrogenicity. Although the individual concentrations of MC are a fraction of the WHO guideline for in drinking water, there is little data on such a low level chronic exposure to aquatic organisms. They also highlight the presence of EE in the water column at critical life stages for aquatic organisms.