A Time-Integrating, Remotely Moored, Automated Sampling and Concentration System for Aquatic Butyltin Monitoring

Antifouling hull paints containing tributyltin (TBT) as the active biocide are becoming the coating of choice for pleasure craft and commercial ships. The recent announcement of the U.S. Environmental Protection Agency of a "Special Review of Certain Pesticide Products Containing Tributyltins Used as Antifoulants" will result in an examination of the environmental risks involved in the use of TBT. Therefore, a need exists to monitor harbors and estuaries for nanogram per liter concentrations of TBT and of its substantially less toxic biodegraded decomposition products. One purpose of such a monitoring effort is to determine time-dependent concentration trends at biologically sensitive locations and to apply this information to risk assessment. We have evaluated a prototype device to help collect such data. This device is self-contained, battery operated, and can be moored remotely. It can be programmed to process volumes of water at various time intervals over several tidal cycles. The water is pumped through a prefilter, an analyte adsorption/concentration column and an integrating flowmeter. The prefilter and adsorption column are replaced periodically and analyzed. This approach permits the determination of a time-integrated average concentration at a particular location.