title: An automated overlying water-renewal system for sediment toxicity studies.
abstract: An automated water-renewal toxicity test system is described for exposing benthic invertebrates to whole sediments. The system will intermittently deliver laboratory or on-site water for overlying water replacement in sediment exposures. A range of cycle rates can be used to produce different volume additions of overlying water per day to exposure chambers. The system can be used with six different treatments and eight replicates per treatment producing 48 exposure chambers. Three formulated sediments with variable organic carbon (1.5%, 7.5%) and sand (14%, 63%) content were prepared to test the system exposing amphipods, Hyalella azteca and midges, Chironomus tentans in 10 day whole sediment tests. Intermittent water flow was used with a 90 min cycle time to create two volume additions of laboratory water per 24 h in exposure chambers (180 ml sediment, 320 ml water). Overlying water quality conditions, and survival and growth of both species were consistent and within acceptable limits for the testing requirements of the U.S. EPA guidelines for sediments with freshwater invertebrates.
authors.affiliation: SERC/Department of Environmental Studies, Ecotoxicology and Risk Assessment, Florida International University, 3000 N.E. 151st Street, North Miami, FL 33181, USA. randg@fiu.edu
authors.forename: G M
authors.initials: GM
authors.lastname: Rand
authors.forename: J V
authors.initials: JV
authors.lastname: Wheat
authors.forename: J F
authors.initials: JF
authors.lastname: Carriger
authors.forename: T A
authors.initials: TA
authors.lastname: Lee
mesh_terms: D000818:Animals; D001331:Automation; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D005618:Fresh Water; D019015:Geologic Sediments; D010933:Plankton; D018675:Toxicity Tests / Q000295:instrumentation* / Q000379:methods