MP8 Metals in the Environment: Dietary concerns in Aquatic Systems
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(CAS-1117-821716) Effect of uptake route on bioaccumulation of trace elements in larval amphibians.

Jackson, K¹, Casey, R¹, Snodgrass, J¹, ¹ Towson University, Towson, MD, USA

ABSTRACT- In both field and laboratory exposures to contaminated sediments, organisms may be exposed to elevated trace elements in the inorganic sediment as well as biofilms growing in the same system. Grazers such as larval amphibians have been shown to accumulate trace elements, but due to co-ingestion of inorganic sediments with food items such as algal biofilms it is difficult to separate the relative contributions of the inorganic and organic phases to accumulation in the organism. This study sought to test the relative contributions of contaminated food and contaminated sediment to trace element uptake in Bufo americanus tadpoles. One exposure included algae grown on plastic tiles in the presence of, but not in contact with coal ash (contaminated food). The other exposure included the algae described above plus a thin layer of coal ash sediment, applied by adding coal ash solution to the treatment and allowing it to settle over the algae (contaminated food plus contaminated sediment). Results indicated that substantial amounts of chromium and lead were transferred to the organisms from direct ingestion of sediment as well as from the ingestion of algae. Nickel, arsenic, selenium, and cadmium appeared to accumulate primarily through the algal diet, for there was little difference in accumulation between the two treatments. These results suggest that, for some elements, biofilm trace element levels may be more relevant for predicting bioaccumulation than concentrations in sediments alone.

Key words: sediment, trace elements, amphibians, bioaccumulation