Mercury phase speciation in the surface waters of three Texas estuaries: Importance of colloidal forms Academic Article uri icon

abstract

  • Surface-water samples were collected from Galveston Bay, Corpus Christi Bay, Sabine Lake, and Laguna Madre and analyzed for Hg in the <0.45-μm, 0.45-μm-1-kDa, and <1-kDa fractions. Colloidal material was isolated with an Amicon cross-flow ultrafiltration system which was rigorously tested. Filter-passing Hg concentrations (< 0.45 μm) ranged from 0.12 to 13.6 pM, with the highest values in Corpus Christi Bay. Within Galveston and Corpus Christi Bays, filter-passing Hg exhibited nonconservative estuarine mixing behavior. The colloidal Hg fraction ranged from 12 to 93% of the filter-passing pool and averaged 57±20%, indicating that a major portion of the operationally defined "dissolved" Hg is associated with submicron particles and macromolecules >1 kDa. Colloidal Hg covaries with colloidal organic C concentrations in Galveston Bay waters, suggesting that most of the filter-passing Hg pool is associated with large organic macromolecules. The log of the particle-water partition coefficient (Kd) ranged from 4.6 to 5.2, and covaried with suspended particulate matter concentrations, likely due to the presence of colloidal Hg.

altmetric score

  • 3

author list (cited authors)

  • Stordal, M. C., Gill, G. A., Wen, L., & Santschi, P. H.

citation count

  • 97

publication date

  • January 1996

publisher