MP3 Ecological Relevance of Photo-enhanced Toxicity
Ballroom G, Level 4
2:10 PM - 5:30 PM, Monday, 10 November 2003
Chair: Barron, Mace ,
(108) Toxicity and phototoxicity of high recreational use waters in alpine lakes of the Sierra Nevada.
Oris, J1, Smith, C1, Hoffmann, J1, Allen, B2, Miller, G3, 1 Miami University, Oxford, OH, USA2 University of California Davis Tahoe Research Group, Tahoe City, CA, USA3 University of Nevada Reno, Reno, NV, USA
ABSTRACT- Toxicity tests were conducted under ambient light conditions using water collected from two alpine lakes in the Sierra Nevada. Tests were conducted with water from Lake Tahoe (Tahoe City Marina) in 1997, 2001, and 2002 (pre and post implementation of a carbureted two-cycle engine ban). Tests were conducted with water from Donner Lake (west end public boat launch) in 2001 and 2002. Photo-toxicity was observed in Lake Tahoe water in all years tested. However, toxicity was less in 2001 and 2002 than compared to 1997. Water from Donner Lake was both directly toxic and phototoxic. Phototoxicity was attributed to the presence of polycyclic aromatic hydrocarbons (PAHs) present as a result of motorized watercraft activity, measured by analytical chemistry and correlated with number of boats present and the in situ induction of planar aromatic hydrocarbon metabolizing system genes. The results of this study indicate that in oligotrophic alpine lakes, phototoxicity of PAHs may result from high levels of motorized watercraft activity. In situ experiments still need to be conducted to determine whether this is an ecologically relevant phenomenon.
Key words: Lake Tahoe, solar radiation, Donner Lake, phototoxicity