title: Dendrochemical record of historical lead contamination sources, Wells G&H Superfund site, Woburn, Massachusetts.
abstract: Laser-ablation inductively coupled-plasma mass-spectrometry analysis of red oak (Quercus rubra) from a well documented heavy metal contaminated United States Environmental Protection Agency superfund site in Woburn, Massachusetts reveals decade-long trends in Pb contaminant sources. Lead isotope ratios (207Pb/206Pb and 208Pb/206Pb) in tree rings plot along a linear trend bracketed by several local and regional contamination sources. Statistically significant interannual variations in 207Pb/206Pb suggest that atmospheric Pb is rapidly incorporated into wood, with minimal mobility subsequent to deposition in annual growth rings. We interpret the decadal trends in our record as a changing mixture of local pollution sources and gasoline-derived Pb. Between 1940 and 1970, Pb was predominantly derived from remobilization of local industrial Pb sources. An abrupt shift in 207Pb/206Pb may indicate that local Pb sources were overwhelmed by gasoline-derived Pb during the peak of leaded gasoline emissions in the late 1960s and early 1970s.
authors.affiliation: Department of Earth Sciences, Boston University, Boston, MA 02215, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Burnett
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Kurtz
authors.forename: Daniel
authors.initials: D
authors.lastname: Brabander
authors.forename: Mark
authors.initials: M
authors.lastname: Shailer
mesh_terms: D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis* / Q000266:history / Q000378:metabolism; D004787:Environmental Pollution / Q000009:adverse effects / Q000266:history; D049673:History, 20th Century; D007854:Lead / Q000032:analysis* / Q000266:history / Q000378:metabolism; D007856:Lead Radioisotopes / Q000737:chemistry / Q000378:metabolism; D008404:Massachusetts; D029963:Quercus / Q000254:growth & development; D012987:Soil / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014197:Trees / Q000737:chemistry* / Q000254:growth & development; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D004785:Environmental Pollutants; D007856:Lead Radioisotopes; D012987:Soil; D007854:Lead