title: Spatio-temporal distribution and sources of Pb identified by stable isotopic ratios in sediments from the Yangtze River Estuary and adjacent areas.
abstract: To understand the spatio-temporal distribution and sources of Pb in the sediments of the Yangtze River Estuary and its adjacent areas, 25 surface sediments and 1 sediment core were collected from the study areas. The concentrations of Al and Pb of these sediments exhibit a decreasing trend from the nearshore towards the offshore, with higher concentrations in the coastal areas of the East China Sea (ECS) and southwest of Jeju Island. According to the stable isotopic ratios of Pb, in combination with the elemental ratios and clay mineral data, it is inferred that sedimentary Pb in the surface sediments of the coastal areas of the ECS may come primarily from the Yangtze River, while the Pb southwest of Jeju Island is probably derived from both the Yangtze and Yellow Rivers. The particulate Pb derived from the Yangtze River was possibly dispersed along two paths: the path southward along the coastline of the ECS and the path eastward associated with the Changjiang Diluted Water (CDW), which crosses the shelf of the ECS towards the area southeast of Jeju Island. Although the Yangtze River Basin witnessed rapid economic development during the period from the late 1970s to the middle 1990s, the influence of human activity on Pb concentration remained weak in the Yangtze River Estuary. Since the early 2000s, however, sedimentary Pb has been significantly increasing in the coastal mud areas of the ECS due to the increasing influence of human activity, such as the increase in atmospheric emission of anthropogenic Pb in China, construction of the Three Gorges Dam (TGD), and the construction of smaller dams in the upper reaches of the Yangtze River. Coal combustion and the smelting of non-ferrous metals are possible anthropogenic sources for the sedimentary Pb in the Yangtze River Estuary.
authors.affiliation: Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China; Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.affiliation: Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China; Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China. Electronic address: liujian0550@vip.sina.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China; Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, SOA, Qingdao 266061, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Hu
authors.affiliation: Key Lab of Submarine Geosciences and Technology of the Ministry of Education, Ocean University of China, 238 Songling Road, Qingdao 266100, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.affiliation: Lab of Marine and Coastal Geology, Third Institute of Oceanography, SOA, 178 Daxue Road., Xiamen 361005, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China; Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China.
authors.forename: Xilin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Lab of Submarine Geosciences and Technology of the Ministry of Education, Ocean University of China, 238 Songling Road, Qingdao 266100, China.
authors.forename: Dejiang
authors.initials: D
authors.lastname: Fan
keywords: Isotopic signatures; Lead; Sediments; Sources; The Yangtze River basin; Transport process