Some Marine units remained in Tsingtao until early May, 1949.Tsingtao was also the headquarters of the Western Pacific Fleet of the US Navy from 1945-1949 and the Marines provided security for the naval facility in the northwest part of the city.
As part of Operation Beleaguer, the 6th Marine Division, under the command of General Lemuel C.
Shepherd (later Commandant of the Marine Corps), was ordered to carry out the mission in the Tsingtao-Chefoo area.
Records from the sediment core revealed that the total PCDD/Fs in the Qingdao coastal sea were nearly constant since 1951 till 1980s and increased remarkably after 1980s.
The total 2,3,7,8-substituted PCDD/Fs and total TEQs of PCDD/Fs on the lipid basis in the mussel sample inside the bay were significantly higher than in the adjacent sediment.
It is in the northeastern part of China on the east coast, north of Shanghai and southeast of Beijing.