Abstract:Bisphenol A is an environmental endocrine disruptor, and is regarded as the third most important global environmental problem that needs to be solved, after the Ozone hole and global warming. It also features on the European Union blacklist of priority pollutants and international organizations have confirmed bisphenol A as a permanent organic pollutant. Bisphenol A is introduced to the environment mainly through the production of low concentration emissions in manufacturing processes, or through the manufacture or use of disordered emissions. Research to date indicates that bisphenol A disturbs normal hormone secretion of humans and animals, and that it can lead to metabolic disorders because of its known ability to mimic estrogen. There is therefore much concern about its distribution patterns in the environment. The Yellow River estuary is located in the northeast of Shandong Province, on the southern side of the Bohai Sea. The Yellow River estuary region is rich in fine sediments, transported and deposited by the Yellow River, and, as a very active land-ocean interaction zone, is an ideal region for ecological environmental monitoring research. The Yellow River Conservancy Commission has implemented water and sediment regulation and there have been 13 water-sediment flushing events between 2002 and 2011, in an attempt to solve the problem of sediment deposition in the lower Yellow River. Water-sediment regulation is seen as the only way to improve the time-space imbalance between water and sediment, through washing reservoir and river sediment from the Yellow River into the sea. According to statistics, a total of 50.912 billion cubic meters of water have been discharged to the downstream reaches, and 762 million tons sediment have been washed into the sea in these 13 periods of water-sediment flushing. Since the 1990s, the Yellow River has been ranked second in China's main rivers in terms of its water pollution because of a rapid increase in discharges from land. These pollutants may damage the marine environment once discharged from the Yellow River estuary into the sea.Surveys were carried out in the Yellow River estuary and adjacent areas during one of the water-sediment flushing events (June and July 2011) to evaluate the effects of the flushing on bisphenol A contamination. The evaluation of bisphenol A pollution was based on the concentrations of bisphenol A before water-sediment flushing in the area just upstream of the Yellow River estuary. Results showed that bisphenol A was detected in surface water at all 13 sampling sites. Surface water concentrations of bisphenol A ranged from 13.6 to 64.0 ng/L, and the average concentration was 26.2 ng/L. Bisphenol A concentrations in the sediments were higher, and ranged from 0.559 to 2.73 μg/kg dry weight, with an average concentration of 1.19 μg/kg. Based on these figures, the average concentration of bisphenol A in the sediments was 48 times higher than the average concentration in surface water. Therefore, the water-sediment flushing events had a significant effect on the concentrations of bisphenol A in the surface waters of the Yellow River estuary, during which the contamination of bisphenol A increased sharply. There was a highly significant relationship between bisphenol A concentrations before and after the water-sediment flushing event (P < 0.01), which indicated that pollution inputs from land were a major source of bisphenol A pollution in the Yellow River estuary. Bisphenol A concentrations in sediments sampled before and after the water-sediment flushing event at the coastal station of the Yellow River Estuary were significantly different (P < 0.01). Results show that the contamination decreased significantly after water-sediment flushing. Results suggest that the Yellow River estuary is polluted by bisphenol A, which may compromise the ecological integrity of the area.