title: Environmental changes in Jiaozhou Bay of northern China during the past 90years using metals and biogenic elements in sediments.
abstract: Metals and biogenic elements were analyzed from surface sediments and a 100cm core collected from Jiaozhou Bay in July 2009, to determine how the environment has changed over the past 90years due to increasing anthropogenic influences in this region. High concentrations of biogenic silica (BSi) represented the dominance of diatoms in the bay. Most metals were lower than the marine sediment quality guidelines; however, Hg, Zn, and Mn were at polluted levels. The vertical profiles of biogenic elements and metals in the sediment core suggest that the most significant environmental changes occurred since the 1990s, and three stages could be defined: (1) before 1950, characterized by low concentrations of biogenic elements and metals; (2) between 1950 and 1990, displaying an obvious increase of Hg and a slow increase of biogenic elements; (3) after 1990, reflected by a significant increase of total organic carbon (TOC), total nitrogen (TN), total phosphate (TP), and most metals, but a decrease of BSi. Correlation and principal component analyses indicated that most metals originated from lithogenic sources, industrial and domestic discharges as well as maricultural activities.
authors.affiliation: College of Life Science and Technology, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China. Electronic address: twzh@jnu.edu.cn.
authors.forename: Zhao-Hui
authors.initials: ZH
authors.lastname: Wang
authors.affiliation: College of Life Science and Technology, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.affiliation: College of Life Science and Technology, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.affiliation: College of Life Science and Technology, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
authors.forename: Xin-Xin
authors.initials: XX
authors.lastname: Lu
mesh_terms: D061006:Bays; D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D008670:Metals / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical
keywords: Biogenic elements; Environmental changes; Jiaozhou Bay; Metals; Sediments; Yellow Sea