PARENT SESSION
WA2 Assessing and predicting toxicant effects in an ecologically complex world
9:00 AM to 12:30 PM, Wednesday, 09 May 2001
Session Chair: P. Calow, V. Forbes
Room 2

(304) Field Validation Studies of Long-Term Sediment Toxicity Tests with Hyalella azteca and Chironomus tentans .

Hayward, Jeannie¹, Jones, John¹, Whites, David², Ingersoll, Chris², Mount, Dave³, Ireland, D.⁴, ^{1 2 3 4}

ABSTRACT- The goal of this project is to evaluate whether laboratory exposures to a contaminant concentration series (acute and chronic laboratory tests with Hyalella azteca and Chironomus tentans) were predictive of field exposures (benthic colonization assessments) with the same contaminant concentrations. This comparison was performed with DDD-spiked sediment, and dilutions of a field-collected sediment from Indiana Harbor. The DDD-spiked sediment was made with the following concentrations 4.0, 1.2, 0.36, 0.11, and 0.03 g/goc-DDD. The Indiana Harbor field-collected sediments were diluted as follows 4.0, 1.2, 0.36, 0.11, and 0.03%. The Hyalella azteca DDD toxicity tests resulted in effects at 1.9, 1.2, and 0.78 g/goc-DDD for survival, growth, and reproduction respectively. The Hyalella azteca Indiana Harbor toxicity tests resulted in effects at 1.0 and 0.36% Indiana Harbor sediment for survival and reproduction respectively. The Chironomus tentans DDD toxicity tests resulted in effects at 0.45, 0.52, and 0.03 g/goc-DDD for survival, emergence, and egg production respectively. The Chironomus tentans Indiana Harbor toxicity tests resulted in effects at 0.50, 0.20, and 0.03% Indiana Harbor sediment for survival, emergence, and egg production respectively. The same DDD concentrations and Indiana Harbor sediment-dilutions were also placed in colonization trays and exposed for 12 weeks in a pond. Preliminary results from the field study indicate a decrease in taxa colonizing the higher concentrations. The results from the completed laboratory tests will be compared to results from the field exposures evaluating benthic invertebrate colonization.

Key words: Hyalella azteca , Chironomus tentans , Colonization , DDD