MP13 Aquatic Ecotoxicology
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(SAM-1117-724295) The mayfly, Centroptilium triangulifer, as an indicator of aquatic toxicity.

Samel, A¹, Jackson, J², Sweeney, B², Bouchelle, L¹, Funk, D², ¹ DuPont Haskell Laboratory, Newark, Delaware, USA² Stroud Water Research Center, Avondale, Pennsylvania, USA

ABSTRACT- Aquatic toxicity testing for protecting or setting freshwater quality criteria have been based on results from predominantly fish and non-insect invertebrates (i.e., Daphnia magna, Ceriodaphnia dubia, Hyalella azteca) bioassay studies. Only a few species of sediment-dwelling aquatic insects have been routinely used in bioassay studies (i.e., Chironomus tentans, C. riparius, Hexagenia rigida, H. limbata). Mayflies are an abundant and diverse group of aquatic insects found in most natural streams and rivers worldwide, and are generally considered to be sensitive to environmental perturbation relative to other aquatic insects and non-insects. The mayfly Centroptilium triangulifer has several characteristics that make it well suited as a bioassay organism. It has a relatively short egg and larval stage and can be readily cultured under laboratory conditions. The species is widely distributed and reproduces as parthogenetic clones. Toxicity testing with chlordane was previously conducted and reported. New data presented includes results from 48-hour acute toxicity tests with copper and an insecticide. The 48-hour LC/EC50 values were compared with results from 48-hour acute toxicity studies with Daphnia magna. For both chemicals, the EC₅₀ values for C. triangulifer and D. magna were within 2x of each other. When addressing risk to aquatic fauna, data from studies with additional test organisms, like C. triangulifer can augment an existing toxicity database based on regulatory core test organisms (i.e., fish, Daphnia sp., Chironomus sp.) for new or existing chemicals The data can also be used for developing species sensitivity curves for new or existing chemicals.

Key words: Centroptilium triangulifer, Daphnia magna, Toxicity, Copper