title: Ecotoxicity of siloxane D5 in soil.
abstract: Decamethylcyclopentasiloxane (D5) is a cyclic volatile methyl siloxane (cVMS) commonly found in commercially available products. D5 is expected to enter the terrestrial environment through the deposit of biosolids from sewage treatment plants onto agricultural fields for nutrient enrichment. Little to no information currently exists as to the risks of D5 to the terrestrial environment. In order to evaluate the potential risk to terrestrial organisms, the toxicity of a D5 contaminated biosolid in an agricultural soil was assessed with a battery of standardized soil toxicity tests. D5 was spiked into a surrogate biosolid and then mixed with a sandy loam soil to create test concentrations ranging from 0 to 4074 mg kg(-1). Plant (Hordeum vulgare (barley) and Trifolium pratense (red clover)) and soil invertebrates (Eisenia andrei (earthworm) and Folsomia candida (springtail)) toxicity tests were completed to assess for lethal and sub-lethal effects. Plant testing evaluated the effects on seedling emergence, shoot and root length, and shoot and root dry mass. Invertebrate test endpoints included adult lethality, juvenile production, and individual juvenile dry mass (earthworms only). Soil samples were collected over time to confirm test concentrations and evaluate the loss of chemical over the duration of a test. The toxicity of the D5 was species and endpoint dependent, such that no significant adverse effects were observed for T. pratense or E. andrei test endpoints, however, toxicity was observed for H. vulgare plant growth and F. candida survival and reproduction. Chemical losses of up to 50% were observed throughout the tests, most significantly at high concentrations.
authors.affiliation: Environment Canada, Ecotoxicology and Wildlife Health Division, Biological Assessment and Standardization Section, Ottawa, Ontario, Canada K1V 1C7. jessica.velicogna@ec.gc.ca
authors.forename: Jessica
authors.initials: J
authors.lastname: Velicogna
authors.forename: Ellyn
authors.initials: E
authors.lastname: Ritchie
authors.forename: Juliska
authors.initials: J
authors.lastname: Princz
authors.forename: Marie-Eve
authors.initials: ME
authors.lastname: Lessard
authors.forename: Rick
authors.initials: R
authors.lastname: Scroggins
mesh_terms: D000818:Animals; D017753:Ecosystem; D054750:Ecotoxicology; D009835:Oligochaeta; D063245:Plant Development; D010944:Plants / Q000187:drug effects; D018570:Risk Assessment; D012833:Siloxanes / Q000633:toxicity*; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D012833:Siloxanes; D012989:Soil Pollutants; C114768:decamethylcyclopentasiloxane