Impacts of inland pollution input on coastal water quality of the Bohai Sea

Inland pollutants input is a key impact factor for the coastal water quality of Bohai Sea. The and inland pollutant inputs were analyzed by using monitoring data recent years from State Oceanic Administration. results showed that more than 56% Sea area was unclean seawater in 2012, although improved gradually after time. In 2017, about one-third still had seawater. Inorganic nitrogen, reactive phosphate, petroleum hydrocarbons are main A total approximately 840,000 t transported to sea each year major rivers during 2010–2017. Significant correlations ( p < 0.05) found between third-grade level COD cr , petroleum, NO 3 ? –N, NH 4 + 2 Cu, Pb inferior fourth-grade Pb, –N. standard discharge rate terrestrial-source sewage outlets no 50%. low TP, BOD 5 SS caused 80% monitored areas adjacent selected not meet requirements marine functional area. suggest implementing management plan necessary reduce heavy ecological burdens on zone carried into 18 rivers. terrestrial source around Although since one third belongs 2017. inorganic hydrocarbon metals • About N, P, pollutants. great affected inputs. river outlet mainly derived from. River transportation two routes