Development of a fluorescence method to detect optical brightners in the presence of varying concentrations of fluorescent humic substances: Identifying regions influenced by OSTDS in the estuarine waters of Charlotte Harbor.

Abstract

Techniques were modified and developed to detect optical brighteners (OB), fluorescent laundry additives, in selected residential canals of Charlotte Harbor, FL, to determine where on-site sewage treatment and disposal systems (OSTDS) in the area may be failing. OB was measured with two approaches. The first employed absorbent, dye-free cotton pads that were placed in the canals for two to three days and then recovered. Pads were analyzed for fluorescence under UV illumination (254nm) both visually and with a spectroradiometer to detect absorbed OB. The second method used paired flow-through fluorometers to obtain a continuous record of fluorescence along selected canals with one wavelength monitored to detect the combined signal from humics and OB.