The study looked at the levels of Arsenic (As) in the bottom waters of Jiaozhou Bay in 1981. They found that the As levels were very low and met the standards for seawater quality. The high As content regions were mainly in the coastal waters in the east, northeast, and north of the bay. Different sources led to different high sedimentation regions, with the estuary of Haibo River and coastal waters in the northeast showing the highest levels. Overall, the As levels decreased as the water passed through the bay mouth.