title: Geochemical analysis of sediments from a semi-enclosed bay (Dongshan Bay, southeast China) to determine the anthropogenic impact and source.
abstract: The geochemical compositions of sediments in the Dongshan Bay, a semi-enclosed bay on the southeast coast of China, were obtained to identify pollutant sources and evaluate the anthropogenic impacts over the last 100 years. The results indicated that the metal flux had been increasing since the 1980s. Enrichment factor values (Pb, Zn and Cu) suggested only slight enrichment. The proportion of anthropogenic Pb changed from 9% to 15% during 2000-2014. Coal combustion might be an important contamination source in the Dongshan Bay. The historical variation in the metal flux reflected the economic development and urbanization in the Zhangjiang drainage area in the past 30 years. According to the Landsat satellite remote sensing data, the urbanization area expanded approximately three times from 1995 to 2010. The δ13C values (-21‰ to -23‰) of the organic matter (OM) in the sediments indicated that the OM was primarily sourced from aquatic, terrigenous and marsh C3plants. Nitrogen was mainly derived from aquatic plants and terrigenous erosion before the 1980s. However, the total organic carbon (TOC) contents, total nitrogen (TN) contents and δ15N had been increasing since the 1980s, which suggested that the sources of nitrogen were soil erosion, fertilizer and sewage. In addition, the TOC and TN fluxes in the Dongshan Bay had significantly increased since the 1980s, which reflected the use of N fertilizer. However, the TOC and TN fluxes significantly decreased in the past decade because environmental awareness increased and environmental protection policies were implemented.
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China. Electronic address: xuyonghang@tio.org.cn.
authors.forename: Yonghang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Fujian Provincial Key Laboratory of Coast and Island Management Technology Study, Fujian Institute of Oceanography, Xiamen, 361013, China.
authors.forename: Qinqin
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ye
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China.
authors.forename: Xijie
authors.initials: X
authors.lastname: Yin
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China.
authors.forename: Dongyi
authors.initials: D
authors.lastname: Li
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China.
authors.forename: Aijun
authors.initials: A
authors.lastname: Wang
authors.affiliation: Laboratory of Ocean and Coast Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen, 361005, China.
authors.forename: Yunhai
authors.initials: Y
authors.lastname: Li
mesh_terms: D061006:Bays / Q000737:chemistry*; D002681:China; D004784:Environmental Monitoring / Q000379:methods*; D005308:Fertilizers / Q000032:analysis; D019015:Geologic Sediments / Q000737:chemistry*; D006801:Humans; D019216:Metals, Heavy / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D012722:Sewage / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D005308:Fertilizers; D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D009584:Nitrogen
keywords: Biogenic elements; Dongshan Bay; Heavy metals; Human activities; Pb isotopes; Southeast China