W5 PM Toxicity of Complex Mixtures
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 321-323

(WAN-1117-228146) Mosquitofish as a Sensitive Bioindicator for Toxicity of Biotoxin Mixtures.

Wang, J-S¹, Billam, M¹, Tang, L¹, McKean, C¹, Wang, Z¹, Wang, P¹, Theodorakis, C¹, Kendall, R¹, ¹ Department of Toxicology and The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas, USA

ABSTRACT- Biotoxins are naturally toxic agents produced by bacterial, cyanobacteria, fungi, and some species of plants and marine fish. Biotoxins and their mixtures have been recognized as potent health threats and possible terrorist agents in recent years, however, development of animal models to evaluate the combinative toxic effects of biotoxin mixtures is a challenge in the field of toxicology. In this study, acute and combinative toxicity of biotoxin mixtures containing aflatoxin B₁, T–2 toxin, microcystin–LR, and fumonisin B₁, were assessed in mosquitofish (Gambusia affinis). Preliminary experiments were conducted in 6–months old fish to determine dosing protocol for each studied biotoxin and obtain LC₅₀ values for individual toxins. This was followed by testing various combinations of selected biotoxins to obtain LC₅₀ values in the model. Significant dose responses were noted within observed toxic parameters to treatment. The potency of the various mixtures was gauged through the determination of the combinative toxicity index (interaction index) metric. Overall results demonstrated that mosquitofish is a sensitive bioindicator for testing toxicity of these biotoxin mixtures. Biotoxin mixtures interacted to produce alterations in the toxic responses in the model can generally be classified as additive, synergistic or occasionally antagonistic effects. It can be gathered that biotoxin mixtures containing these toxins may pose a significant threat to public health and further research need to be completed addressing long–term toxic and health effect of human populations daily exposed to these biotoxin mixtures and their roles in known human chronic diseases. (Financially supported by research contracts, DAAD13–00–C–0056, DAAD13–01–C–0053, and DAAD13–02–C–0070 from SBCCOM, DOD)

Key words: mosquitofish, biotoxin mixture, aquatic toxicology, complex mixture