title: Hardness corrections for copper are inappropriate for protecting sensitive freshwater biota.
abstract: Toxicity testing using a freshwater alga (Chlorella sp.), a bacterium (Erwinnia sp.) and a cladoceran (Ceriodaphnia cf. dubia) exposed to copper in synthetic and natural freshwaters of varying hardness (44-375 mg CaCO3/l), with constant alkalinity, pH and dissolved organic carbon concentration, demonstrated negligible hardness effects in the pH range 6.1-7.8. Therefore, the use of a generic hardness-correction algorithm, developed as part of national water quality guidelines for protecting freshwater biota, is not recommended for assessing the toxicity of copper to these, and other, sensitive freshwater species. Use of the algorithm for these sensitive species will be underprotective because the calculated concentrations of copper in water that cause a toxic effect will be higher.
authors.affiliation: Environment Division, Australian Nuclear Science and Technology Organization, Private Mailbag 1, Menai, NSW 2234, Australia.
authors.forename: S J
authors.initials: SJ
authors.lastname: Markich
authors.forename: G E
authors.initials: GE
authors.lastname: Batley
authors.forename: J L
authors.initials: JL
authors.lastname: Stauber
authors.forename: N J
authors.initials: NJ
authors.lastname: Rogers
authors.forename: S C
authors.initials: SC
authors.lastname: Apte
authors.forename: R V
authors.initials: RV
authors.lastname: Hyne
authors.forename: K C
authors.initials: KC
authors.lastname: Bowles
authors.forename: K L
authors.initials: KL
authors.lastname: Wilde
authors.forename: N M
authors.initials: NM
authors.lastname: Creighton
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001681:Biological Assay; D002118:Calcium / Q000032:analysis; D002244:Carbon / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002708:Chlorella / Q000254:growth & development*; D033361:Cladocera / Q000254:growth & development*; D003300:Copper / Q000737:chemistry* / Q000633:toxicity; D004885:Erwinia / Q000254:growth & development*; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000032:analysis; D013816:Thermodynamics; D014881:Water Supply / Q000032:analysis
chemical_list: D002244:Carbon; D003300:Copper; D008274:Magnesium; D002118:Calcium