title: Growth, development and incidence of deformities in amphibian larvae exposed as embryos to naphthenic acid concentrations detected in the Canadian oil sands region.
abstract: Naphthenic acids (NA) have been identified as harmful environmental contaminants that influence survival, growth and development of wildlife. Amphibian larvae are particularly susceptible to waterborne contaminants, but little information exists regarding exposure of amphibian embryos or tadpoles to NA. Our results demonstrate that embryos of Lithobates pipiens and Silurana tropicalis exposed to 2-4 mg/l of a commercial NA blend suffer significant reductions (32% and 25%, respectively) in growth and development upon hatching. Increased incidences of deformities were observed in exposed individuals of both species, but were only significant in L. pipiens. Embryos suffered 100% mortality following exposure to 6 mg/l NAs, and narcosis at lower concentrations. LC50 estimates were 4.10 mg/l for 72-h exposure in L. pipiens and 4.13, 3.51, and 2.95 mg/l for 24-, 48-, and 72-h exposure in S. tropicalis. These data suggest that exposure to NAs at environmentally realized concentrations may negatively affect tadpole populations.
authors.affiliation: Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5. steve.melvin@unb.ca
authors.forename: Steven D
authors.initials: SD
authors.lastname: Melvin
authors.forename: Vance L
authors.initials: VL
authors.lastname: Trudeau
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000453:epidemiology; D000818:Animals; D002170:Canada; D002264:Carboxylic Acids / Q000032:analysis / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D062665:Epidemiological Monitoring; D048788:Growth and Development / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D059392:Petroleum Pollution / Q000009:adverse effects / Q000032:analysis; D011898:Ranidae; D014981:Xenopus
chemical_list: D002264:Carboxylic Acids; D004785:Environmental Pollutants; C046170:naphthenic acid