title: Comparison of laboratory batch and flow-through microcosm bioassays.
abstract: Since 1997, we have been developing a protocol for ecotoxicological bioassays in 2-L laboratory microcosms and have applied it to the study of various pollutants and ecotoxicological risk assessment scenarios in the area of urban facilities and transport infrastructures. The effects on five different organisms (micro-algae, duckweeds, daphnids, amphipods, chironomids) are assessed using biological responses such as growth, emergence (chironomids), reproduction (daphnids) and survival, with a duration of exposure of 3 weeks. This bioassay has mainly been used as a batch bioassay, i.e., the water was not renewed during the test. A flow-through microcosm bioassay has been developed recently, with the assumption that conditions for the biota should be improved, variability reduced, and the range of exposure patterns enlarged (e.g., the possibility of maintaining constant exposure in the water column). This paper compares the results obtained in batch and flow-through microcosm bioassays, using cadmium as a model toxicant. As expected, the stabilization of physico-chemical parameters, increased organism fitness and reduced variability were observed in the flow-through microcosm bioassay.
authors.affiliation: Université de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRS, 3, rue Maurice Audin, 69518 Vaulx-en-Velin, France. Electronic address: bernard.clement@entpe.fr.
authors.forename: Bernard J P
authors.initials: BJ
authors.lastname: Clément
authors.affiliation: Université de Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE, CNRS, 3, rue Maurice Audin, 69518 Vaulx-en-Velin, France; DREAL Rhône-Alpes, 69453 Lyon, France.
authors.forename: Hélène L
authors.initials: HL
authors.lastname: Delhaye
authors.affiliation: Centre d'expertise en analyse environnementale du Québec, Ministère du Développement durable, de l'Environnement, de la Faune et des Parcs, Division Écotoxicologie et Évaluation du risque, Complexe Scientifique 2700, rue Einstein, bureau E-2-220, Sainte Foy, QC, Canada G1P 3W8.
authors.forename: Gaëlle G
authors.initials: GG
authors.lastname: Triffault-Bouchet
mesh_terms: D033304:Amphipoda; D000818:Animals; D001681:Biological Assay; D002104:Cadmium / Q000633:toxicity*; D002683:Chironomidae; D003621:Daphnia; D054750:Ecotoxicology / Q000379:methods*; D005260:Female; D019684:Magnoliopsida; D008297:Male; D058086:Microalgae; D018675:Toxicity Tests / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium
keywords: Cadmium; Ecotoxicity; Flow-through assay; Microcosm; Variability