Monday, 18 November 2002
D0033

This presentation is part of : Student Competition Display Presentations, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology

Joint acute toxicity of atrazine and four organophosphate insecticides to Chironomus tentans (Diptera: Chironomidae)

Troy D. Anderson, Mamy Rakotondravelo, and Kun Yan Zhu. Kansas State University, Department of Entomology, 123 West Waters Hall, Manhattan, KS

The acute toxicity of atrazine in binary combination with each of four organophosphate insecticides (OP; dimethoate, omethoate, disulfoton, and demeton-s-methyl) was evaluated with fourth-instar larvae of the aquatic midge, Chironomus tentans (Diptera: Chironomidae) in 48-h bioassays. OP concentrations resulting in an effect in 15% (EC15) of midges were coupled to atrazine concentrations of 0, 1, 10, 100, and 1,000 g/L to determine the effect of atrazine on the toxicity of each OP. Atrazine alone (up to 1,000 g/L) did not show noticeable acute toxicity to C. tentans. However, atrazine (³ 100 g/L) either significantly increased or decreased the toxicity of the OPs (EC15) in the combinations. Synergism or antagonism ratios were calculated to determine the magnitude of the effect of atrazine on the toxicity of the OPs. Acetylcholinesterase (AChE) activity also was examined in the midges treated with individual OPs or the mixtures of atrazine and each OP for 48 h.

Species 1: Diptera Chironomidae Chironomus tentans
Keywords: synergism, antagonism

Back to Student Competition Display Presentations, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology
Back to Student Competition Poster
Back to The 2002 ESA Annual Meeting and Exhibition