Biodegradation of Tributyltin by Chesapeake Bay Microorganisms

We have been studying microbial resistance to butyltin compounds and the degradation of tributyltin spiked into samples of Chesapeake Bay waters. Butyltin species were identified and quantified using a gas chromatograph equipped with a tin-selective flame photometric detector (GC-FPD), providing ng/l detection limits. No biodegradation of a tributyltin spike ( g/l, final concentration) was detected in water samples (from Annapolis and Baltimore Harbor) collected in winter and incubated in the laboratory at the in situ temperature. However, degradation of tributyltin to dibutyltin and monobutyltin species was detected in samples collected in summer. Incubation of these samples under incandescent lamps accelerated biodegradation, suggesting the involvement of photosynthetic microorganisms. At certain times in these degradation experiments, tetrabutyltin was detected by GC-FPD and confirmed by gas chromatography-mass spectrometry.