title: Decamethylcyclopentasiloxane (D5) spiked sediment: bioaccumulation and toxicity to the benthic invertebrate Hyalella azteca.
abstract: Chronic toxicity and bioaccumulation of decamethylcyclopentasiloxane (D5) to Hyalella azteca was examined in a series of spiked sediment exposures. Juvenile H. azteca were exposed for 28d (chronic) to a concentration series of D5 in two natural sediments of differing organic carbon content (O.C.) and particle size composition. The chronic, LC50s were 191 and 857μgD5g(-1) dry weight for Lakes Erie (0.5% O.C.) and Restoule (11% O.C.) respectively. Inhibition of growth only occurred with the L. Restoule spiked sediment with a resultant EC25 of 821μgg(-1)dw. Lethality was a more sensitive endpoint than growth inhibition. Biota sediment accumulation factors (BSAFs, 28d) were <1 indicating that D5 did not bioconcentrate based on lipid normalized tissue concentrations and organic carbon normalized sediment concentrations. Organic carbon (OC) in the sediment appeared to be protective, however normalization to OC did not normalize the toxicity. Normalization of D5 concentrations in the sediments to sand content did normalize the toxicity and LC50 values of 3180 and 3570μg D5g(-1) sand dw were determined to be statistically the same.
authors.affiliation: Aquatic Ecosystems Protection Research Division, Environment Canada, P.O. Box 5050, Burlington, Ontario, Canada L7R 4A6. Electronic address: warren.norwood@ec.gc.ca.
authors.forename: W P
authors.initials: WP
authors.lastname: Norwood
authors.forename: M
authors.initials: M
authors.lastname: Alaee
authors.forename: E
authors.initials: E
authors.lastname: Sverko
authors.forename: D
authors.initials: D
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Brown
authors.forename: M
authors.initials: M
authors.lastname: Galicia
mesh_terms: D033304:Amphipoda / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry; D007928:Lethal Dose 50; D012833:Siloxanes / Q000378:metabolism* / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
chemical_list: D012833:Siloxanes; D014874:Water Pollutants, Chemical; C114768:decamethylcyclopentasiloxane