MP11 Advances in Bioaccumulation Assessment
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(WIG-1117-574939) Cadmium exposure effects on tissue metal concentrations in two tolerant and two sensitive crayfish species.

Wigginton, A¹, Price, D¹, Birge, W¹, ¹ University of Kentucky, Lexington, KY, USA

ABSTRACT- Four 96h acute toxicity tests were performed with the crayfish O. juvenilis, O. placidus, P.acutus, and P. clarkii with various concentrations of cadmium and control groups. O. placidus and P. acutus were more sensitive with LC50 values of 0.487 and 0.368 mg Cd/L, while O. juvenilis and P. clarkii were more tolerant with LC50 values of 2.44 and 2.66 mg Cd/L, respectively. Tissue samples, including gills, green glands, hemolymph, hepatopancreas, muscles, ovaries, exoskeletal and remaining tissues, and testes, were dissected from survivors and analyzed for their content of Ca, Cd, Cu, Fe, Mg, P, Sr, Zn and various other elements. Whole body elemental content (mg/kg) values were derived from the preceding. In most tissues, cadmium tissue content correlated strongly with cadmium exposure. Cd tissue residues were compared to exposure concentrations to calculate 96h BCFs. Regression analysis was used to derive equations estimating the curve of 96h BCFs to allow for better comparisons between species. Cd accumulated more strongly in the hepatopancreas, gills and green glands of sensitive species than in tolerant species. These data seem to indicate that a fundamental difference exists between how sensitive and tolerant crayfish species either take in or excrete heavy metals. Zn tended to show negative correlations with Cd exposure in the hepatopancreas. Cu showed several strong trends versus Cd tissue concentrations. Cu increased in green glands, gills, and hemolymph and, in some cases, decreased in the hepatopancreas. Ca, Fe, Mg, and Zn also showed significant trends. These data indicate that Cd may displace Cu and/or Zn in the hepatopancreas and the displaced metal then may move into other tissues, especially the gills and green glands, possibly to be excreted.

Key words: crayfish, cadmium, toxicity, tissue residue