Bill Martin Linda Kalnejais Mike Bothner Contaminant Metals in Boston Harbor: Processes Influencing long-term fate Bill Martin Linda Kalnejais Mike Bothner

Study Site:Hingham Bay 2000 - 2008

Ag, Pb, and Cu: 1980 - 2002

Cu, Ag, and Pb All are associated with organic matter : Cu > Ag, Pb All form stable complexes and sparingly soluble solid phases with S(-II) All coprecipitate with / sorb to Fe oxides : Pb > Ag, Cu

Depth Distributions of Sedimentary Processes Hingham Bay Site (not to scale)

Data Treatment: Averaged and smoothed profiles

Fe and S cycling Winter

Fe and S cycling Summer

Late Summer / Early Fall Fe and S cycling Late Summer / Early Fall

Trace Metal Cycling: Cu - Winter

Trace Metal Cycling: Cu - Summer

Trace Metal Cycling: Cu - Late summer

Compare: Cu and Ag

Compare: Cu and Pb

The sedimentary environment

Sediment Resuspension: Experimental Setup

Sediment Resuspension: Mass resuspended vs. bottom stress

Solid Phase Metals

Dissolved metals

Longer-term release from resuspended particles Incubations: Filled : particle incubations Open: filtered controls

Bottom stress at the Hingham Bay Site

Including Sediment-Seawater exchange in the budget for Cu in Boston Harbor

Conclusions Remobilization of contaminant metals, deposited earlier, may be a significant source of metals to Boston Harbor. Ongoing work: Complete analyses and interpretation of Boston Harbor and Mass Bay experiments. To date: Kalnejais (2005) - PhD Thesis (and presentations at AGU, ASLO, GSA) Oates (2008) MS Thesis Morford et al. (2007) Kalnejais et al. (2007) Martin and Kalnejais (2007) Future work: Update and extend contaminant metal budgets for Boston Harbor Determine distributions of particulate metals in Mass. Bay - especially after important resuspension events