Evaluation of short-term chronic in situ testing with Hyalella azteca and Chironomus tentans
- Wright State Univ., Dayton, OH (United States)
Traditional toxicity testing of simple grab samples is limited by uncertainties arising from extrapolations of laboratory results to field situations. Long term testing in lakes and streams measured the effects of intermittent storm events and contamination from sediments. Aquatic organisms are enclosed in plastic containers with 149 um mesh openings. These chambers were anchored to the bottom allowing continual water exchange and association with sediments to occur. This study was designed to evaluate the effectiveness of chronic in situ testing (one to four weeks of exposure) with Chironomus tentans and Hyalella azteca. With the addition of 0.01 g of rabbit pellets per chamber as a food source, H. azteca survival was greater than 80% after four weeks of exposure. Testing with H. azteca was limited by cold water temperatures (< 12 C). The midge C. tentans required a silica sand or shredded paper towel substrate added to the chambers. C. tentans were more sensitive to handling stress and stream flow than H. azteca. maximizing the usefulness of in situ testing with chronic exposures allows lethal, sub-lethal, and bioaccumulation effects to be measured.
- OSTI ID:
- 367437
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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