title: Bioavailability, ecotoxicity, and geological characteristics of trace lead in sediments from two sites on Negro River, Uruguay, South America.
abstract: Bioassays of two sites along the Rio Negro in Uruguay indicate ecotoxicity, which could be attributable to trace concentrations of lead in river sediments. Monthly samples at two sites at Baygorria and Bonete locations were analyzed for both particle size and lead. Lead was determined by atomic spectrometry in river water and sediment and particle size by sieving and sedimentation. Data showed that Baygorria's sediments have greater percentage of clay than Bonete's (20.4 and 5.8%, respectively). Lead was measurable in Baygorria's sediments, meanwhile in Bonete's, it was always below the detection limit. In water samples, lead was below detection limit at both sites. Bioassays using sub-lethal growth and survival test with Hyalella curvispina amphipod, screening with bioluminescent bacteria Photobacterium leiognathi, and acute toxicity bioassay with Pimephales promelas fish indicated toxicity at Baygorria, with much less effect at Bonete. Even though no lethal effects could be demonstrated, higher sub-lethal toxicity was found in samples from Baygorria site, showing a possible concentration of the contaminant in the clay fraction.
authors.affiliation: Water and Chemicals Department, Technological Laboratory of Uruguay (LATU), Avda. Italia 6201, PO Box: 11500, Montevideo, Uruguay. dmiguez@latu.org.uy
authors.forename: Diana M
authors.initials: DM
authors.lastname: Míguez
authors.forename: Raquel
authors.initials: R
authors.lastname: Huertas
authors.forename: María V
authors.initials: MV
authors.lastname: Carrara
authors.forename: Agustín
authors.initials: A
authors.lastname: Carnikián
authors.forename: María E
authors.initials: ME
authors.lastname: Bouvier
authors.forename: María J
authors.initials: MJ
authors.lastname: Martínez
authors.forename: Karen
authors.initials: K
authors.lastname: Keel
authors.forename: Carolina
authors.initials: C
authors.lastname: Pioda
authors.forename: Elena
authors.initials: E
authors.lastname: Darré
authors.forename: Ramiro
authors.initials: R
authors.lastname: Pérez
authors.forename: Santiago
authors.initials: S
authors.lastname: Viera
authors.forename: Enrique
authors.initials: E
authors.lastname: Massa
mesh_terms: D033304:Amphipoda / Q000187:drug effects*; D000818:Animals; D001681:Biological Assay; D001682:Biological Availability; D003530:Cyprinidae / Q000378:metabolism*; D019015:Geologic Sediments / Q000737:chemistry*; D007854:Lead / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity; D010316:Particle Size; D010776:Photobacterium / Q000187:drug effects*; D045483:Rivers / Q000737:chemistry*; D023382:Toxicity Tests, Acute; D014583:Uruguay; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D007854:Lead