Developing Microbial Inocula to Support Biofuel Crop Cultivation on Tributyltin Contaminated Marine Sediments

Abstract

Tributyltin (TBT) is a synthetic organotin compound and is recognised as the most toxic chemical ever knowingly introduced into the marine environment. Organotins have a wide range of application with an estimated global production of 50,000 tons per year therefore impacts from TBT can be seen or anticipated in many environments including protected areas like aqua farms and world heritage sites effecting aquaculture and undisturbed ecosystems. Due to the impact of TBT a necessity exists for the treatment of contaminated sediment and soil using nature-based solutions as it is both non-invasive and sustainable. However these remediation techniques must also be economically interesting to increase its acceptance. Thus using the biomass from plant species with the ability to cultivate in dredged sediment for biofuel and biomaterials production should be considered to ensure that renewable energy consumption of 10% is meet by 2020. The objectives of this study is to investigate the potential of Hordeum vulgare and Brassica napus to cultivate in marine sediments despite the salinity and TBT pollution for a 30 day pot trial. Further to inoculate seedling roots with known TBT degrading bacteria to enhance the phytoremediation capacity. Also to establish if bacterial isolates C7 and C22 are plant growth promoting bacteria. Statistical analysis on seedlings biomass was carried out followed by analytical analyses by atomic absorption spectroscopy (AAS) and sediment analysis by gas chromatography mass spectrometry (GC-MS). Results showed a maximum decrease of ≥ 82% and ≥ 80% of TBT in sediment samples respectively with bacteria inoculum C7 (KX881905) and C22 (KX881904), further Hordeum vulgare seedlings were the ideal candidate plant species with a significant production of biomass.