title: Lethal and sub-lethal effects of triclosan toxicity to the earthworm Eisenia fetida assessed through GC-MS metabolomics.
abstract: Triclosan (TCS) is a ubiquitous contaminant in municipal biosolids, which has also been detected in soils and earthworms sampled from agricultural fields amended with biosolids. The goal of this study was to evaluate the toxicity of TCS to earthworms using a metabolomics-based approach for an improved interpretation of toxicity. Toxicity of TCS was assessed using the OECD Method 207 filter paper contact test measuring the endpoints of weight loss, mortality, and ten metabolites determined by GC-MS. Eight earthworms were exposed as individual replicates to six concentrations of triclosan (0, 0.0001, 0.001, 0.01, 0.1, and 1mg TCS cm-2) on filter paper, with mortality assessed after 6, 24 and 48h. Mortalities were first observed at 24h, with 100% mortality in the 1 and 0.1mgcm-2treatments. Worms at 1mgcm-2lost most of their coelomic fluid before they could be sampled. The 48h LC50for triclosan was estimated to be 0.006 and 0.008mgcm-2by a linear and logistic model, respectively. Based on the LC50, triclosan is relatively more toxic to earthworms than a number of other emerging contaminants, but is less toxic than other chlorophenols and many pesticides. Alanine, valine, leucine, serine, phenylalanine, putrescine, spermidine, mannitol, and inositol were significantly different between treatments, although changes were most often associated with mortality rather than triclosan exposure. An increase in putrescine and decrease in amino acids, polyols, and spermidine were associated with mortality, suggesting decomposition had begun. Principal components analysis did not reveal evidence of metabolic impacts at sub-lethal concentrations. However, there were changes in the pattern of correlations between metabolite pairs in surviving worms at both 0.0001 and 0.001mgcm-2exposure compared to the control.
authors.affiliation: Department of Bioresource Engineering, McGill University, Faculty of Agricultural and Environmental Sciences, Macdonald-Stewart Building MS1-027, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Quebec, H9X 3V9, Canada. Electronic address: joseph.gillis@mail.mcgill.ca.
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Gillis
authors.affiliation: Department of Engineering, Dalhousie University, Faculty of Agriculture, 39 Cox Road, PO Box 550, Truro, Nova Scotia, B2N 5E3, Canada.
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Price
authors.affiliation: Department of Bioresource Engineering, McGill University, Faculty of Agricultural and Environmental Sciences, Macdonald-Stewart Building MS1-027, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.
authors.forename: Shiv
authors.initials: S
authors.lastname: Prasher
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D008401:Gas Chromatography-Mass Spectrometry; D055442:Metabolome / Q000187:drug effects*; D055432:Metabolomics; D009835:Oligochaeta / Q000187:drug effects* / Q000378:metabolism; D025341:Principal Component Analysis; D012989:Soil Pollutants / Q000633:toxicity*; D016019:Survival Analysis; D023382:Toxicity Tests, Acute; D014260:Triclosan / Q000633:toxicity*
chemical_list: D012989:Soil Pollutants; D014260:Triclosan
keywords: Earthworms; GC–MS; MZMine 2; Metabolomics; OpenChrom; Triclosan