title: Assessing the chronic toxicity of copper and aluminium to the tropical sea anemone Exaiptasia pallida.
abstract: The world's most productive bauxite mines and alumina refineries are located in tropical or sub-tropical regions. The discharge water from alumina refineries can contain elevated aluminium (Al, <0.45µm fraction), from 30 to 1000μg/L. There is a need for additional information on the toxicity of Al to aquatic organisms to improve the environmental regulation and management of alumina refinery operations in tropical coastal regions. A 14-d chronic toxicity test was developed for the tropical sea anemone Exaiptasia pallida. Asexual reproduction and growth rates of E. pallida were assessed using the number of lacerates produced and oral disc diameter. The comparative sensitivity of E. pallida was assessed through exposure to a commonly-used reference toxicant, copper (Cu) at 28°C, with asexual reproduction toxicity estimates of 10% (EC10) and 50% (EC50) effect concentrations, calculated as 8.8µg/L (95% confidence limits (CL): 1-18µg/L) and 35µg/L Cu (95% CL: 30-39µg/L), respectively. Growth rate was a suitable additional endpoint (EC50=35µg/L Cu, 95% CL: 23-49µg/L). The EC10 and EC50 for Al (total fraction, based on reproduction) at 28°C were 817µg/L (95% CL: 440-1480µg/L) and 2270µg/L (95% CL: 1600-3900µg/L), respectively. The toxicity of Cu and Al was also assessed at 24°C and 31°C, representing average year-round water temperatures for sub-tropical and tropical Australian coastal environments. Changing the temperature from 28°C to 24°C or 31°C resulted in up to 45% less reproduction of anemones and increased their sensitivity to Cu (EC50s at 24°C=21µg/L, 95% CL: 17-26µg/L and at 31°C=23µg/L, 95% CL: 21-25µg/L). Sensitivity to Al was reduced at 24°C with an EC50 of 8870µg/L (95% CL: 6200-NC). An EC50 for Al at 31°C could not be calculated. This test is a reliable and sensitive addition to the suite of standardised tests currently developed for tropical marine species.
authors.affiliation: North Australian Marine Research Alliance, Charles Darwin University, Darwin, Northern Territory 0909, Australia; Australian Institute of Marine Science, 23 Ellengowan Dve, Brinkin, Northern Territory 0811, Australia; Environmental Research Institute of the Supervising Scientist, GPO Box 461, Darwin, NT 0801, Australia. Electronic address: melanie.trenfield@environment.gov.au.
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Trenfield
authors.affiliation: Australian Institute of Marine Science, 23 Ellengowan Dve, Brinkin, Northern Territory 0811, Australia.
authors.forename: Joost W
authors.initials: JW
authors.lastname: van Dam
authors.affiliation: Environmental Research Institute of the Supervising Scientist, GPO Box 461, Darwin, NT 0801, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Harford
authors.affiliation: Rio Tinto Aluminium, 123 Albert St, Brisbane, Queensland 4000, Australia; Charles Darwin University, Darwin, Northern Territory 0909, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Parry
authors.affiliation: Australian Institute of Marine Science, 23 Ellengowan Dve, Brinkin, Northern Territory 0811, Australia.
authors.forename: Claire
authors.initials: C
authors.lastname: Streten
authors.affiliation: North Australian Marine Research Alliance, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Gibb
authors.affiliation: Environmental Research Institute of the Supervising Scientist, GPO Box 461, Darwin, NT 0801, Australia.
authors.forename: Rick A
authors.initials: RA
authors.lastname: van Dam
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D000818:Animals; D003300:Copper / Q000633:toxicity*; D012100:Reproduction, Asexual / Q000187:drug effects; D012615:Sea Anemones / Q000187:drug effects; D036401:Toxicity Tests, Chronic; D014329:Tropical Climate; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper; D000535:Aluminum
keywords: Alumina refinery; Metal toxicity; North Australia; Temperature