Arsenic in Urban Lakes


field work, Puget sound region

In the Puget Sound region, lakebed sediments are contaminated with arsenic emitted from the former Tacoma copper smelter (shut down in 1985) and they now act as a long-term source of arsenic to surface water and animals living in the lakes. As part of the UW Superfund Research Program, we are investigating the mobility, bioaccumulation and ecological toxicity of arsenic within these impacted urban lakes. The contamination affected lakes with different mixing regimes and we have detected arsenic in the waters of both shallow unstratified lakes and deep seasonally stratified lakes. Our specific aims are to:

  • Identify physical and biogeochemical lake attributes that promote arsenic mobilization from sediments and maintain elevated aqueous concentrations of arsenic in lake water of both seasonally stratified and unstratified lakes.

  • Determine the physical and biogeochemical factors that control arsenic bioaccumulation through aquatic food webs in both seasonally stratified and unstratified lakes.

  • Assess ecological toxicity of arsenic at different trophic levels within both seasonally stratified and unstratified lakes using established and novel molecular biomarkers that indicate arsenic stress and injury.

These efforts will establish the human and ecological health-threat posed by arsenic contamination, and will provide information needed to revise arsenic water-quality guidelines, which are under review.

Funding: National Institute of Environmental Health Sciences, Superfund Research Program

people currently involved with project:

Samantha Fung

Jim Gawel (UW Tacoma)

Becca Neumann


Barrett, P. M., E.A. Hull, EK. Burkart, O. Hargrave, J. McLean, V.F. Taylor, B.P. Jackson, J.E. Gawel, R.B. Neumann (2019) Contrasting arsenic cycling in strongly and weakly stratified contaminated lakes: Evidence for temperature control on sediment–water arsenic fluxes. Limnology and Oceanography, doi:10.1002/lno.11119.

Barrett, P. M., E.A. Hull, C. E. King, K. Burkart, K. A. Ott, J.N. Ryan, J. E. Gawel, R.B. Neumann (2018)  Increased exposure of plankton to arsenic in contaminated weakly-stratified lakes, Science of the Total Environment, 625, 1606–1614, doi:10.1016/j.scitotenv.2017.12.336.

data sets:

Barrett, Pamela M; Neumann, Rebecca B; Gawel, James E (2018): Water-column aqueous arsenic, oxygen, and temperature; arsenic content of sediment, porewater, plankton, and sediment trap samples in two lakes in the Puget Sound lowland (2016-2018). PANGAEA,

Barrett, Pamela M; Neumann, Rebecca B; Gawel, James E (2017): Aqueous arsenic, oxygen, temperature, and plankton arsenic content in urban lakes in the Puget Sound lowland from September 2015 to August 2016. PANGAEA,