title: A study of the shape of dose-response curves for acute lethality at low response: a "megadaphnia study".
abstract: Dose-response curves were developed for the immobilization response in Daphnia magna to four toxicants. The purpose of this work was to study the effect of the form of the model and the number of concentration levels used on the estimates of typical low-dose effective concentrations (1%, 5%, 10%). The generalized four-parameter logistic model was used as the reference. When using 12 concentration levels, one of the logistic family two- or three-parameter models was shown reliably to represent each of these various sets of dose-response data, and to provide adequate estimates of EC01 and EC05, as well as EC10 and EC50. For two of the toxicants, an asymmetric model was required. When reducing the number of concentrations to five, the EC10 and EC50 were well estimated by the probit model, with acceptable results at the EC05 level.
authors.affiliation: Sebaugh's Information Services, Lake Ozark, Missouri 65049.
authors.forename: J L
authors.initials: JL
authors.lastname: Sebaugh
authors.forename: J D
authors.initials: JD
authors.lastname: Wilson
authors.forename: M W
authors.initials: MW
authors.lastname: Tucker
authors.forename: W J
authors.initials: WJ
authors.lastname: Adams
mesh_terms: D000818:Animals; D007631:Chlordecone / Q000633:toxicity; D003300:Copper / Q000633:toxicity; D019327:Copper Sulfate; D003621:Daphnia / Q000187:drug effects*; D004126:Dimethylformamide / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D064420:Drug-Related Side Effects and Adverse Reactions; D006801:Humans; D016015:Logistic Models; D008452:Maximum Allowable Concentration; D008627:Mercuric Chloride / Q000633:toxicity; D004364:Pharmaceutical Preparations / Q000008:administration & dosage
chemical_list: D004364:Pharmaceutical Preparations; D008627:Mercuric Chloride; D003300:Copper; D004126:Dimethylformamide; D019327:Copper Sulfate; D007631:Chlordecone