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Robin Stewart

Research Hydrologist

Contact Info

Short Biography

Permanent 2003 US Geological Survey National Research Program

Postdoctorate 1999 US Geological Survey, Water Resources Division, Menlo Park, California, USA

Postdoctorate 1998 Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba, Canada

PhD 1998 University of Manitoba, Winnipeg, Canada

BSc 1991 University of Victoria, British Columbia, Canada


Stewart AR, Luoma SN, Elrick KA, Carter JL, van der Wegen M (2013) Influence of Estuarine Processes on Spatiotemporal Variation in Bioavailable Selenium. Mar Ecol Prog Ser 492:41-56 [Link]

Huffman, R.L., Wagner, R.J., Toft, J., Cordell, J., DeWild, J.F., Dinicola, R.S., Aiken, G.R., Krabbenhoft, D.P., Marvin-DiPasquale, M., Stewart, A.R., Moran, P.W., and Paulson, A.J., 2012. Mercury species and other selected constituent concentrations in water, sediment, and biota of Sinclair Inlet, Kitsap County, Washington, 2007–10: U.S. Geological Survey Data Series 658, 64 p.

Selck H, Drouillard K, Eisenreich K, Koelmans AA, Palmqvist A, Ruus A, Salvito D, Schultz I, Stewart, A.R., Weisbrod A, van den Brink NW, van den Heuvel-Greve M (2011) Explaining differences between bioaccumulation measurements in laboratory and field data through use of a probabilistic modeling approach. Integr Environ Assess Manage 7:1-22. 

Kleckner, A.E., Stewart, A.R., Elrick, K., and Luoma, S.N., 2010, Selenium concentrations and stable isotopic compositions of carbon and nitrogen in the benthic clam Corbula amurensis from Northern San Francisco Bay, California: May 1995–February 2010: U.S. Geological Survey Open-File Report 2010-1252, 34 p. 

Stewart AR, Grosell M, Buchwalter DB, Fisher N, Luoma SN, Mathews T, Orr PL, Wang WX (2010) Bioaccumulation and trophic transfer of selenium. In: Chapman PM, Adams WJ, Brooks ML, Delos CG, Luoma SN, Maher WA, Ohlendorf HM, Presser T, Shaw DP (eds) Ecological Assessment of Selenium in the Aquatic Environment: Summary of a SETAC Pellston Workshop. Society of Environmental Toxicology and Chemistry (SETAC), Pensacola, FL (USA). 

Grimaldo, L.F., Stewart, A.R., and Kimmerer, W. Dietary segregation of pelagic and littoral fish assemblages in a highly modified tidal freshwater estuary. Marine and Coastal Fisheries Dynamics Management and Ecosystem Science (2009) 1: 200-217.

Chasar, L.C., Scudder, B.C., Stewart, A.R., Bell, A.H., and Aiken, G.R. 2009. Mercury cycling in stream ecosystems: 3. Trophic dynamics and methylmercury bioaccumulation. Environ. Sci. Technol. 43 (8), 2733-2739.

Alpers, C.N., Stewart, A.R., Saiki, M.K., Marvin-DiPasquale, M., Topping, B.R., Rider, K.M., Gallanthine, S.K., Kester, C.A., Rye, R.O., Antweiler, R.C., and DeWild, J.F. 2008. Environmental factors affecting mercury in Camp Far West Reservoir, 2001-03 USGS SIR 2006-5008, Sacramento, CA.

Stewart, A.R., Saiki, M.K., Kuwabara, J.S., Alpers, C.N., Marvin-DiPasquale, M., and Krabbenhoft, D.P. 2008. Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir. Can. J. Fish. Aquat. Sci. 65: 2351-2366.

Luoma, S.N., Anderson, S.A., Bergamaschi, B., Holm, L., Ruhl, C., Schoellhamer, D.H., and Stewart, A.R. 2008. Water Quality. p. 55-72. In The State of Bay-Delta Science, 2008. Edited by M.C. Healey, M.D. Dettinger and R.B. Norgaard. Calfed Science Program, Sacramento.

Marvin-DiPasquale, M., Stewart, A. R., Fisher, N.S., Pickhardt, P., Mason, R.P. , Heyes, A., and Windham-Myers, L.. 2007. Evaluation of Mercury Transformations and Trophic Transfer in the San FranciscoBay/Delta: Identifying Critical Processes for the Ecosystem Restoration Program. Final Report of Progress for Project #ERP-02-P40 to the California Bay-Delta Authority (CBDA), Sacramento, CA; California Bay-Delta Authority.

Croteau, M-N., Luoma, S.N. and Stewart, A.R. 2005. Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature. Limnol. Oceanogr.  50: 1511-1519.

Schlekat, C.E., Kidd, K.A., Adams, W.J., Baird, D.J., Farag, A.M., Maltby, L, and Stewart, A.R.  2005. Toxic Effects of Dietborne Metals: Field Studies. p. 113-144. In Toxicity of Dietborne Metals to Aquatic Organisms. Edited by J.S. Meyer, W.J. Adams, K.V. Brix, S.N. Luoma, D.R. Mount, W.A. Stubblefield and C.M. Wood. SETAC Press, Pensacola, Florida, USA.

Luoma, S.N., and Stewart, A.R. 2005. Processes Affecting Trophic Transfer and Resultant Effects of Metals. p. 247-258. In Toxicity of Dietborne Metals to Aquatic Organisms. Edited by J.S. Meyer, W.J. Adams, K.V. Brix, S.N. Luoma, D.R. Mount, W.A. Stubblefield and C.M. Wood. SETAC Press, Pensacola, Florida, USA.

Adams, W.J., Stewart, A.R., Kidd, K.A., Brix, K.V., and DeForest, D.K. 2005. Case Histories of Dietborne Exposure to Mercury and Selenium in Aquatic Ecosystems. p. 263-273. In Toxicity of Dietborne Metals to Aquatic Organisms. Edited by J.S. Meyer, W.J. Adams, K.V. Brix, S.N. Luoma, D.R. Mount, W.A. Stubblefield and C.M. Wood. SETAC Press, Pensacola, Florida, USA.

Stewart, A.R., Luoma, S.N., Schlekat, C.E., Doblin, M.A. and Hieb, K.A. 2004. Food web pathway determines how selenium affects aquatic ecosystems: A San Francisco Bay case study. Environ. Sci. Technol. 38:4519-4526.

Kuwabara, J. S., Alpers, C.N., Marvin-Dipasquale, M., Topping, B.R., Carter, J. L., Stewart, A. R., Fend, S. V., Parchaso, F., Moon, G.E., Krabbenhoft, D.P. 2003. Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California, USGS OFR-2003-4140.

Stewart A.R., G.A. Stern, W.L. Lockhart, K.A. Kidd, A.G. Salki, M.P. Stainton, K. Koczanski, G.B. Rosenberg, D.A. Savoie, B.N. Billeck, P. Wilkenson, and D.C.G. Muir. 2003. Assessing trends in organochlorine concentrations in Lake Winnipeg fish following the 1997 Red River Flood.  J. Great. Lakes Res. 29 (2): 332-354.

Baines, S.B., N.S. Fisher, and A.R. Stewart.  2002. Assimilation of Se and trace metals from food in juvenile striped bass.  Limnol. Oceanogr. 47: 646-655.

Stewart, A.R. et al. 2001. Applications of stable isotopes research in understanding complex ecological processes in the San Francisco Estuary. Interagency Ecological Program for the San Francisco Estuary.  IEP Newsletter 14(4): 27-32.

Stewart, A.R., Stern, G.A., Salki, A., Stainton, M.P., Lockhart, W.L., Billeck, B.N., Danell, R., Delaronde, J., Grift, N.P., Koczanski, K., MacHutcheon, A., Rosenberg, B., Savoie, D., Tenkula, D., Tomy, G., and Yarchewski, A. 2000.  Effects of the 1997 Red River flood on contaminant transport and fate in southern Lake Winnipeg.  International Red River Basin Task Force.

Stewart, A.R. and Malley, D.F. 1999.  The effect of a metal mixture (Cu, Zn, Pb and Ni) on cadmium bioavailability and accumulation by the freshwater macrophyte Eriocaulon septangulare.  Environ. Toxicol. Chem. 18:436-447.

Stewart, A.R.  1999.  Accumulation of cadmium by a freshwater mussel (Pyganodon grandis) is reduced in the presence of other metals.  Can. J. Fish. Aquat. Sci. 56: 467-478.

Stewart, A.R.  1998.  Effect of a metal mixture (Cu, Zn, Pb and Ni) on the bioavailability and bioaccumulation of cadmium in natural systems.  Ph.D. Thesis, Dept. of Botany, University of Manitoba. 

Stewart, A.R.  1997.  Technical evaluation of molluscs as biomonitoring tools for the Canadian Mining Industry.  Natural Resources Canada. Aquatic Effects Technical Evaluation Program. 248 p.

Malley, D.F., Stewart, A.R. and Hall, B.D.  1996.  Uptake of methyl mercury by the floater mussel, Pyganodon grandis (Bivalvia, Unionidae), caged in a flooded wetland.  Environ. Tox. Chem. 15: 928-936.


My Science Topics

Science Topic
Ecology and Environmentaquatic ecosystems
Ecology and Environmentecological processes
Water Resourcesestuaries
Water Resourceslakes
Water Resourcessurface water quality
Water Resourceswater quality

Bioavailability, bioaccumulation and trophic transfer of selenium and mercury in dynamic aquatic ecosystems

Dietary contaminants such as selenium (Se), mercury (Hg) and organic chemicals have the potential to threaten fish and birds, and impede ecosystem restoration efforts in rivers, lakes and estuaries worldwide. For example, Se contamination remains an ongoing issue for resource managers because it is a by-product of common economic activities including coal-fire generation of electricity, oil refining, agriculture, and mining of phosphate, copper and uranium.  Understanding the complexities of Se behavior in ecosystems is critical because of the potential for future changes in Se source loading, water management, hydroclimatic conditions and ecosystem restoration that could alter Se exposures in the food web, potentially exacerbating the problem. 

For the past twenty years my research has focused on identifying and understanding processes influencing the fate and bioavailability of Se and Hg and organic contaminants in food webs across a range of aquatic environments including estuaries (San Francisco Bay and Puget Sound), rivers (Oregon, Wisconsin and Florida), and tidal rivers and reservoirs (California).  Through a combination of field-based process studies, in situ monitoring of key biomonitors over short-term (<3 years) and long-term (>10 years) time series, biodyanamic modeling and knowledge gained through laboratory-based studies of physiological uptake I have identified critical processes controlling contaminant bioaccumulation in nature.  

Research Links

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Contact Information

Robin Stewart
345 Middlefield Road
Menlo Park, CA 94025
650-329-4545 - Fax
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