title: Potential of two hydra species as standard toxicity test animals.
abstract: The potential for using pink hydra (Hydra vulgaris) and green hydra (Hydra viridissima) as a model invertebrate for the toxicity testing of xenobiotics was investigated. Test compounds were 4-chlorophenol, endosulfan, and copper. The reference toxicant 4-chlorophenol was used as a standard during toxicity testing to ensure the sensitivity of hydra did not change over time. Hydra had a low sensitivity to 4-chlorophenol and endosulfan compared to other freshwater species. The 96-h LC50 (SE) values for 4-chlorophenol and endosulfan were 32 mg/L (1.3) and 0.81 mg/L (0.1), respectively, for pink hydra, and 45 mg/L (6.1) and 0.67 mg/L (0.02), respectively, for green hydra. Based on population growth rates, the 6-day NOEC and LOEC results for pink hydra exposed to 4-chlorophenol and endosulfan were <1.1 and 1.1 mg/L, and 0.044 microg/L and 0.080 mg/L, respectively; results for green hydra were 10.3 and 22.3 mg/L, and 0.060 and 0.080 mg/L, respectively. Following exposure to copper, the 96-h LC50 (SE) values were 26 microg/L (3.4) for pink hydra and 8.5 microg/L (0.3) for green hydra, respectively. Based on population growth rates, the 7-day population growth NOEC and LOEC values for both pink and green hydra exposed to copper were 4 and 8 microg/L, respectively. Results indicate that hydra have the potential for use in acute and subchronic toxicity testing of inorganic toxicants, but have a low sensitivity to organic toxicants.
authors.affiliation: Department of Applied Biology and Biotechnology, RMIT City-Campus, Melbourne, Victoria, 3001, Australia.
authors.forename: C A
authors.initials: CA
authors.lastname: Pollino
authors.forename: D A
authors.initials: DA
authors.lastname: Holdway
mesh_terms: D000465:Algorithms; D000818:Animals; D002733:Chlorophenols / Q000633:toxicity; D003300:Copper / Q000633:toxicity; D004726:Endosulfan / Q000633:toxicity; D005618:Fresh Water; D006829:Hydra / Q000254:growth & development / Q000502:physiology*; D007306:Insecticides / Q000633:toxicity; D007928:Lethal Dose 50; D011153:Population; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D002733:Chlorophenols; D007306:Insecticides; D015262:Xenobiotics; C029107:4-chlorophenol; D003300:Copper; D004726:Endosulfan