title: A century long sedimentary record of anthropogenic lead (Pb), Pb isotopes and other trace metals in Singapore.
abstract: Reconstructing the history of metal deposition in Singapore lake sediments contributes to understanding the anthropogenic and natural metal deposition in the data-sparse Southeast Asia. To this end, we present a sedimentary record of Pb, Pb isotopes and eleven other metals (Ag, As, Ba, Cd, Co, Cr, Cu, Ni, Tl, U and Zn) from a well-dated sediment core collected near the depocenter of MacRitchie Reservoir in central Singapore. Before the 1900s, the sedimentary Pb concentration was less than 2 mg/kg for both soil and sediment, with a corresponding (206)Pb/(207)Pb of ∼1.20. The Pb concentration increased to 55 mg/kg in the 1990s, and correspondingly the (206)Pb/(207)Pb decreased to less than 1.14. The (206)Pb/(207)Pb in the core top sediment is concordant with the (206)Pb/(207)Pb signal of aerosols in Singapore and other Southeast Asian cities, suggesting that Pb in the reservoir sediment was mainly from atmospheric deposition. Using the Pb concentration in the topmost layer of sediment, the estimated atmospheric Pb flux in Singapore today is ∼1.6 × 10(-2) g/m(2) yr. The concentrations of eleven other metals preserved in the sediment were also determined. A principal component analysis showed that most of the metals exhibit an increasing trend towards 1990s with a local concentration peak in the mid-20(th) century.
authors.affiliation: Asian School of the Environment, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Singapore-MIT Alliance on Research and Technology, Center of Environmental Sensing and Modelling, 1 CREATE Way, #09-03 CREATE Tower, 138602, Singapore. Electronic address: chen0327@e.ntu.edu.sg.
authors.forename: Mengli
authors.initials: M
authors.lastname: Chen
authors.affiliation: Singapore-MIT Alliance on Research and Technology, Center of Environmental Sensing and Modelling, 1 CREATE Way, #09-03 CREATE Tower, 138602, Singapore; Department of Earth, Atmospheric, and Planetary Sciences, E25-619, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Boyle
authors.affiliation: Asian School of the Environment, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Singapore-MIT Alliance on Research and Technology, Center of Environmental Sensing and Modelling, 1 CREATE Way, #09-03 CREATE Tower, 138602, Singapore; Earth Observatory of Singapore, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Switzer
authors.affiliation: Earth Observatory of Singapore, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Chris
authors.initials: C
authors.lastname: Gouramanis
mesh_terms: D002947:Cities; D004784:Environmental Monitoring; D004787:Environmental Pollution / Q000032:analysis*; D019015:Geologic Sediments / Q000032:analysis*; D007554:Isotopes / Q000032:analysis; D060106:Lakes / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D019216:Metals, Heavy / Q000032:analysis*; D012846:Singapore; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014131:Trace Elements / Q000032:analysis
chemical_list: D007554:Isotopes; D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D014131:Trace Elements; D007854:Lead
keywords: Heavy metals; Pb; Pb isotopes; Sediment; Singapore; Southeast Asia