W.R. Blair

Accumulation and fate of tri-n-butyltin cation in estuarine bacteria

The accumulation and possible metabolic transformation of tri-n-butyltin cation by tin-resistant estuarine bacteria was studied. The bacterial isolates accumulated tributyltin to 3.7–7.7 mg tin per g dry weight of cells by a nonenergy requiring process, probably by adsorption to the cell envelope. Chemical speciation of cell extracts and culture media by combined liquid chromatography-atomic absorption spectrophotometry and tin-selective purge and trap flame photometric gas chromatography for possible tributyltin degradation products revealed no significant biotransformations of tributyltin cation by the tributyltin-resistant isolates. Apparently the isolates accumulate, but do not metabolize tributyltin.

Ultratrace Speciation and Biogenesis of Methyltin Transport Species in Estuarine Waters

Environmental tin, widely dispersed at low concentrations in waters, sediments, and biota, is shown to be a bioactive element susceptible to methylation and even hydridization by marine bacteria. The redox cycle of tin in natural waters is poorly understood and recent advances in tin-specific molecular characterization fail to speciate Sn(II) and Sn(IV) reliably. Nonetheless, such rapid developments in speciation methodology now permit growing numbers of studies of organotin distributions in aquatic systems, raising the question of the “natural” biogeochemical flux of methylstannanes in relation to increased anthropogenic organo-tin influx from industry and shipping. New methods for direct speciation of aquated or involatile organotins by liquid chromatography are compared with advances in purge-and-trap sampling of volatile or hydrophobic organotins speciated by gas chromatography. The work in our laboratory indicates that effective models for estuarine formation and transport may ultimately be developed, but that basic roadblocks to progress stem from inadequate descriptive aqueous organometallic chemistry and knowledge of critical kinetic parameters for the lifetimes of key organotin species in sea water, occurring at sub-nanomolar concentrations.

A modified method for quantifying methyl and butyltins in estuarine sediments

Abstract A method is presented for the rapid determination of organotins in aquatic sediments. It employs extraction of sediments with acidic methanol, formation of organotin hydrides, chromatographic separation of individual hydrides, and element-specific detection with quartz furnace atomic absorption spectrometry. The method has been applied to sediments from Boston Harbor.

Speciation Measurements of Butyltins: Application to Controlled Release Rate Determination and Production of Reference Standards

This paper describes methods and results of the determination of release rates for organotin species released from organotin impregnated wood pilings. The analytical method consists of simultaneous extraction/hydridization of aqueous leachate samples, with organotin speciation by gas chromatography coupled with tin selective flame photometric detection (GC-FPD). The sensitivity of the FPD detector to the butyltin family of organotins is 0.1 to 0.2 ng, depending on the species. Chromatographic separation of the butyltins provides speciation of mono- through tetrabutyltin within a 15 min chromatogram, with the additional capability of identifying any methylbutyltin compounds that may be present in the sample. Water samples were collected from the piling leaching tanks immediately upon immersion of the pilings and continued to be collected for approximately 1 year. Speciation and release rate data were obtained on both the early, first order stage of organotin release, and the latter, zeroth order phase of controlled release. Instrument calibrations were performed using a specially prepared organotin research material.