摘要
According to the survey data of three voyages in the offshore area of northern Shandong in May,August and October 2018,the distribution characteristics and water qualities of DIN,PO_(4-)P and COD in different seasons were analyzed,and the eutrophication status of the sea area was assessed by single factor index,eutrophication index and organic pollution comprehensive index.The results showed that the seawater in the surveyed area mainly belonged to class I and class II seawater,and DIN was the maximum factor influencing seawater quality.The planar distribution of DIN concentrations showed a decreasing trend from west to east,and high value areas appeared near the Yellow River Estuary and Xiaoqing River Estuary.The concentrations of PO_(4-)P were lower,and the planar distribution law was not obvious.The concentrations of COD were high near shore and low offshore,high in the western sea area and low in the eastern sea area.The eutrophication status of the sea area was not up to the eutrophication level,and red tides were less likely to occur,but there was a possibility of organic pollution.
