Historical Profiles of Trace Element Concentrations in Mangrove Sediments from the Ba Lat Estuary, Red River,Vietnam Nguyen Tai Tue & Tran Dang Quy & Atsuko Amano & Hideki Hamaoka & Shinsuke Tanabe & Mai Trong Nhuan & Koji Omori Received: 2 May 2011 / Accepted: 1 September 2011 / Published online: 15 September 2011 # Springer Science+Business Media B.V. 2011 AbstractHistorical profiles of trace element concen- trationswere reconstructed from two mangrove sediment cores collected within the Ba Lat Estuary (BLE), Red River,Vietnam. Chronologies of sedi- mentcoreswere determined by the 210 Pb method, which showed that each respective sediment core from the south and north entrances of BLE provided a record ofsediment accumulation spanning approxi- mately 100 and 60 years. The profiles of Pb, Zn, Cu, Cr, V, Co, Sb, and Sn concentrations markedly increased from the years of the 1920s–1950s, and leveled out from 1950s–1980s, and then gradually decreased from 1980s to present. The profiles of Cd and Ag concentrations increased from 1920s–1940s, and then decreased from 1940s to present. The profi of Mo concentrations progressively increased from 1920s–1980s, then decreased to present. The Mn concentrations failed to show a clear trend in both sediment cores.Results from contamination factors, Pearson’s correlation, and hierarchical cluster analys suggest thatthe trace elements were likely attributed to dischargeof untreated effluents from industry, domesticsewage,as well as non-pointsources. Pollution Load Index (PLI)revealed levels higher than other mangrove sediment studies, and the long- term variations in PLI matched significant socioeco- nomicshifts and population growth in Vietnam. Geoaccumulation Index showed that mangrove sedi- ments were moderately polluted by Pb and Ag, and from unpolluted to moderately polluted by Zn, Cu, and Sb. The concentrations of Pb, Zn, Cu, Cr, and Cd exceeded the threshold effect levels and effect range concentrations of sediment quality guidelines, implyi that the sediments may be occasionally associated w adverse biological effects to benthic organisms. Keywords Historical profiles . Trace element . Mangrove sediment . Ba Lat Estuary . Vietnam 1 Introduction Mangrove ecosystems act as natural filters for retain sediments and pollutants thatoriginate from land- Water Air Soil Pollut (2012) 223:1315–1330 DOI 10.1007/s11270-011-0947-x N. T. Tue (*) : H. Hamaoka : S. Tanabe : K. Omori Center for Marine Environmental Studies, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan e-mail: tuenguyentai@gmail.com N. T. Tue e-mail: tuent@sci.ehime-u.ac.jp T. D. Quy : M. T. Nhuan Faculty of Geology, Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi,Vietnam A. Amano Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8567, Japan