Sediment contamination is a prevailing environmental problem. Sediments in lower section of rivers and in estuarine area are often contaminated by hydrophobic organic compounds (HOCs) and heavy metals. In the soils and sediments in Taiwan, multiple contaminants concentrations were ranked at the top in the world, for example, the dioxins and mercury in at An-Sun site in Tainan, the polybrominated diphenylethers and mercury in the sediments of Nan-Ken River. Similarly, this situation is also quite common in the southeastern Asia. This research team in the past few years has developed a new technology for soil and sediment remediation, i.e., in situ phase inversion emulsification and biological reductive dihalogenation (ISPIE/BiRD). This method is not only very effective in removal of weathered polychlorinated biphenyls and hexachlorobenzene in river sediments but also achieved as high as 99.9% removal of DDT and 92.2% removal of Lindane in soils.

This proposed project is a 2-year project. Before September of 2023, it is expected to finish a series of batch degradation experiments and a small-scale column study. By using quantitative polymerase chain reaction (qPCR) to quantify functional genes and using the third-generation gene sequencing (TGS) technology to conduct microbial community analysis to confirm the optimal reaction conditions. Through the deep machine learning of artificial intelligence, the key factors influencing the biodegradation of BDE-209 under high mercury concentration can be identified. The mechanisms of mercury on the biodegradation of PBDEs in the sediments can be understood.

In the second year (Sept. 1, 2023 to Aug. 31, 2024), a field pilot study will be conducted to validify the results of the first-year project. In addition, deep machine learning will be applied to the results of the second-year chemical analysis and microbial gene sequencing results to improve the prediction model and key factors of ISPIE/BiRD in sediment remediation.