Bioassays to the Rescue: Unveiling Overlooked Ecological and Food Safety Consequences of Sediment Contamination in Hangzhou Bay, China

This PhD thesis investigated how sediment-associated contaminants affect marine environmental quality and seafood safety in the Yangtze River Delta (YRD), one of China’s most industrialized and densely populated regions. Focusing on Hangzhou Bay, a major estuarine area receiving inputs from multiple rivers and urban-industrial centres, the study addresses limitations in current Chinese marine monitoring, which mainly targets water-column contaminants and a narrow set of sediment pollutants. Such monitoring may underestimate ecological risks because sediments can act as long-term sinks for complex contaminant mixtures, including legacy pollutants and emerging bioactive compounds such as PAHs, PCBs, dioxin-like compounds, and other industrial chemicals. This thesis therefore developed and applied an integrated ecotoxicological assessment approach combining long-term monitoring data, chemical analyses, and novel bioassays. By integrating environmental monitoring with effect-based testing, the research provides a framework for assessing benthic pollution, ecological risks, and potential implications for seafood safety.