Assessing metal bioavailability from cytosolic metal concentrations in natural populations of aquatic insects
- Geological Survey, Menlo Park, CA (United States)
Metals occur in a variety of forms in aquatic insects. Some of these forms may be irrelevant to effects of metals on the animal, and might actually obscure links between tissue residues, metal bioavailability and toxicity (e.g. metals sorbed to external body parts, or associated with unpurged gut contents). Cytosolic metal may be a sensitive indicator of metal bioavailability and toxicity. The authors determined cytosolic metal concentrations in natural populations of the caddisfly (Trichoptera) Hydropsyche occidentalis. Cytosolic metal concentrations were compared to whole-body and sediment metal concentrations. Samples were collected along a contamination gradient over a 380 km reach of the Clark Fork River, Montana, in August of 1992 and 1993. Concentrations of cytosolic Cd, Cu, and Pb correlated with concentrations of these metals in the whole body within years. Cytosolic metals also correlated with levels of sediment contamination except at the most contaminated sites where metal concentrations in the cytosol were lower relative to sediments. The availability of Pb appeared to be low since the cytosolic Pb fraction represented less than 6% of the total Pb body burden. The cytosol contained appreciably higher proportions of the total Cd and Cu body burden than Pb. The cytosolic fraction of Cd and Cu also increased significantly between 1992 and 1993. This change reflected an increase in Cd and Cu exposure in 1993, apparently due to the mobilization of metals during higher river flows that year. The shift in cytosolic metal fractions demonstrates the dynamic nature of metal partitioning in animals in nature. These shifts can be influenced by hydrologic and geochemical conditions, as well as biological processes.
- OSTI ID:
- 212003
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9617%%319
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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