Christopher Finnegan^1,, David Ryan¹, Anne-Marie Enright¹, Guiomar Garcia-Cabellos¹

Tributyltin (TBT) is the most toxic chemical ever knowingly introduced into the marine environment, exerting lethal effects on a wide variety of marine organisms. Due to the impact of TBT a necessity exists for the screening of TBT resistant and degrading bacteria for the treatment of contaminated marine sediment. Therefore the approach taken for this study was to isolate and identify new TBT resistant and utilising microbes from marine sediments and soils. In addition to carry out and optimise batch TBT biodegradation assays to measure the TBT degradation rate and the production of the degradation products dibutyltin (DBT) and monobutyltin (MBT) over 21 days. Assays used to screen isolates identified six candidate strains which were characterised and utilised in biodegradation assays. Liquid, from biodegradation assays were analysed on gas chromatography mass spectrometry, which accurately measured and identified tributyltin and differentiated between TBT and the degradation products (DBT and MBT). Results showed a maximum decrease of ≥70% TBT in liquid samples recovered from batch assays and increases in the levels of DBT and MBT the least toxic of the compounds by 32% and 19% respectively, indicating the bacterial breakdown of TBT.

tributyltin, microorganisms, contaminated soils, marine sediments, bioremediation, characterisation, gas chromatography