Metals in Yellow River estuary sediments during the 2018 water-sediment regulation scheme period.

The Water-Sediment Regulation Scheme (WSRS) in the Yellow River has greatly changed the natural state of water and sediment discharges into the sea, which is likely to have a significant impact on the ecological environment in the estuary and even Bohai Sea. Based on a total of 33 surface sediment samples collected in the Yellow River estuary during the WSRS in 2018, analyses of grain size, contents of heavy metals, major elements, and clay minerals were conducted to evaluate sources and pollution status of heavy metals. The results indicated that sediment compositions were significantly impacted by the process of the WSRS. Most metals were from natural sources, but As may be affected by human activities. Contamination assessments of heavy metals revealed that the WSRS had limited impact on the ecology environment, but As could be a threat to the environment.