title: Effects of alumina refinery wastewater and signature metal constituents at the upper thermal tolerance of: 1. The tropical diatom Nitzschia closterium.
abstract: Ecotoxicological studies, using the tropical marine diatom, Nitzschia closterium (72-h growth rate), were undertaken to assess potential issues relating to the discharge from an alumina refinery in northern Australia. The studies assessed: (i) the species' upper thermal tolerance; (ii) the effects of three signature metals, aluminium (Al), vanadium (V) and gallium (Ga) (at 32°C); and (iii) the effects of wastewater (at 27 and 32°C). The critical thermal maximum and median inhibition temperature for N. closterium were 32.7°C and 33.1°C, respectively. Single metal toxicity tests found that N. closterium was more sensitive to Al compared to Ga and V, with IC(50)s (95% confidence limits) of 190 (140-280), 19,640 (11,600-25,200) and 42,000 (32,770-56,000) μg L(-1), respectively. The undiluted wastewater samples were of low toxicity to N. closterium (IC(50)s>100% wastewater). Environmental chemistry data suggested that the key metals and discharge are a very low risk to this species.
authors.affiliation: Environmental Research Institute of Supervising Scientist (ERISS), Supervising Scientist Division, Department of Sustainability, Environment, Water, Population and Communities, GPO Box 461, Darwin 0801, Northern Territory, Australia. Andrew.harford@environment.gov.au
authors.forename: A J
authors.initials: AJ
authors.lastname: Harford
authors.forename: A C
authors.initials: AC
authors.lastname: Hogan
authors.forename: J J
authors.initials: JJ
authors.lastname: Tsang
authors.forename: D L
authors.initials: DL
authors.lastname: Parry
authors.forename: A P
authors.initials: AP
authors.lastname: Negri
authors.forename: M S
authors.initials: MS
authors.lastname: Adams
authors.forename: J L
authors.initials: JL
authors.lastname: Stauber
authors.forename: R A
authors.initials: RA
authors.lastname: van Dam
mesh_terms: D000535:Aluminum / Q000032:analysis / Q000633:toxicity*; D017377:Diatoms / Q000187:drug effects* / Q000254:growth & development; D005708:Gallium / Q000032:analysis / Q000633:toxicity*; D006358:Hot Temperature; D007220:Industrial Waste; D008669:Metallurgy; D012623:Seawater / Q000737:chemistry; D014329:Tropical Climate; D014639:Vanadium / Q000032:analysis / Q000633:toxicity*; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D014639:Vanadium; D005708:Gallium; D000535:Aluminum