From Sarasota Bay Estuary Program Director Dave Tomasko:
Successful resource management efforts have to be grounded in solid science. Both in Tampa Bay and Sarasota Bay, we have the privilege of working with talented individuals doing great science. The paper linked here is an example of this type of management-relevant science.
Our colleagues at the University of Florida (UF) and the Tampa Bay Estuary Program (TBEP), led by UF’s Dr. Elise Morrison, used a variety of tracers and water quality parameters to track the duration and spatial extent of impacts from the discharges of industrial wastewater from Piney Point. Of particular interest is the nitrogen isotope work. The ratio between two isotopes of nitrogen (N-15 and N-14) has been used for decades to distinguish between nitrogen loads from wastewater vs. nitrogen loads from "fertilizer".
Well, the industrial wastewater that was released from Piney Point not only had excessively high values of nitrogen (over 200 mg/L, more than 10 times as concentrated as what came into our waterways from the Bee Ridge Wastewater Treatment Plant (WWTP) overflows) but it also had an isotopic signature that was extremely unique. This wasn't "fertilizer". It was a pool of 200 million gallons of fertilizer that had been processed by the algal blooms that had been feeding off that fertilizer for more than 20 years. As a result, the isotopic signature of the discharges gave rise to a value that had not previously been recorded in our local waters. This unique signature thus acted as a "tracer" of the spatial distribution of the plume.
So how far away was this isotopic signature found? More than 40 miles away, up close to Tarpon Springs. It was found in the “reference site” that I proposed to UF researchers – a location far enough away from Tampa Bay that it was thought it would be isolated from the impacts that were anticipated in Tampa and Sarasota Bays.