title: A Cautionary Note: Ceriodaphnia dubia Inter-Laboratory Test Variability.
abstract: An inter-laboratory comparison of the three-brood survival and reproduction Ceriodaphnia dubia toxicity test was conducted involving three toxicity testing laboratories. This comparison was initiated due to sporadic toxicity with this test related to discharge of a mine effluent, which some regulators believed indicated adverse effects in the receiving environment. One mine effluent and two receiving water samples were evaluated. There were no adverse effects on C. dubia survival in any tests. However, sublethal effects on reproduction (i.e., the IC25; the concentration that causes a 25 % inhibitory effect in the measured sublethal endpoint) ranged from 35 % to >100 % among all test treatments. All laboratories were certified for this test and followed established procedures. Dilute mineral water appears to be the best medium for culturing, dilution, and control water. Variability in the C. dubia laboratory toxicity test should not be mistaken for adverse effects in receiving environments.
authors.affiliation: Golder Associates Ltd., 102, 2535 - 3rd Avenue S.E., Calgary, AB, T2A 7W5, Canada. laura_pacholski@golder.com.
authors.forename: Laura
authors.identifier: http://orcid.org/0000-0002-3554-6359
authors.initials: L
authors.lastname: Pacholski
authors.affiliation: Chapema Environmental Strategies Ltd., 1324 West 22nd Street, North Vancouver, BC, V7P 2G4, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Chapman
authors.affiliation: De Beers Canada Inc., Suite 300, 5120-49 Street, Yellowknife, NT, X1A 1P8, Canada.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Hood
authors.affiliation: De Beers Canada Inc., Suite 300, 5120-49 Street, Yellowknife, NT, X1A 1P8, Canada.
authors.forename: Michelle
authors.initials: M
authors.lastname: Peters
mesh_terms: D000818:Animals; D033361:Cladocera / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D012098:Reproduction / Q000187:drug effects; D018675:Toxicity Tests / Q000379:methods*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D014867:Water
keywords: Ceriodaphnia dubia; Freshwater; Inter-laboratory; Toxicity; Variability