Monitoring Organotin Concentrations in Maryland Waters of Chesapeake Bay

A monthly sampling program for dibutyltin (DBT, tributyltin (TBT) and tetrabutyltin (TTBT) was initiated for a period of one year in the Maryland portion of Chesapeake Bay. Concentrations of the above butyltin species were evaluated in eight sampling stations representing two small and two large marinas, a large harbor, two major river systems and a heavily used shipping channel. Ultra-trace concentrations of DBT, TBT and TTBT were evaluated in the surface microlayer and water column using a gas chromatograph with a flame photometric detector. Approximately half of the total projected samples have been analyzed for presentation in this paper. Maximum microlayer concentrations of 1156, 1171 and 526 ng/L DBT, TBT and TTBT, respectively, have been reported. The highest water column concentrations reported were 276 ng/L DBT, 464 ng/L TBT and 38 ng/L TTBT.