title: Identification of compounds bound to suspended solids causing sub-lethal toxic effects in Daphnia magna. A field study on re-suspended particles during river floods in Ebro River.
abstract: Identifying chemicals causing adverse effects in organisms present in water remains a challenge in environmental risk assessment. This study aimed to assess and identify toxic compounds bound to suspended solids re-suspended during a prolonged period of flushing flows in the lower part of Ebro River (NE, Spain). This area is contaminated with high amounts of organochlorine and mercury sediment wastes. Chemical characterization of suspended material was performed by solid phase extraction using a battery of non-polar and polar solvents and analyzed by GC-MS/MS and LC-MS/MS. Mercury content was also determined for all sites. Post-exposure feeding rates of Daphnia magna were used to assess toxic effects of whole and filtered water samples and of re-constituted laboratory water with re-suspended solid fractions. Organochlorine and mercury residues in the water samples increased from upstream to downstream locations. Conversely, toxic effects were greater at the upstream site than downstream of the superfund Flix reservoir. A further analysis of the suspended solid fraction identified a toxic component eluted within the 80:20 methanol:water fraction. Characterization of that toxic component fraction by LC-MS/MS identified the phytotoxin anatoxin-a, whose residue levels were correlated with observed feeding inhibition responses. Further feeding inhibition assays conducted in the lab using anatoxin-a produced from Planktothrix agardhii, a filamentous cyanobacteria, confirmed field results. This study provides evidence that in real field situation measured contaminant residues do not always agree with toxic effects.
authors: Department of Environmental Chemistry, IDÆA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
authors: Claudia
authors: C
authors: Rivetti
authors: Department of Environmental Chemistry, IDÆA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
authors: Cristian
authors: C
authors: Gómez-Canela
authors: Department of Environmental Chemistry, IDÆA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
authors: Silvia
authors: S
authors: Lacorte
authors: Department of Environmental Chemistry, IDÆA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
authors: Sergi
authors: S
authors: Díez
authors: Centro de Estudos em Limnologia, Biodiversidade e Etnobiologia do Pantanal, Universidade Estadual de Mato Grosso (UNEMAT), Mato Grosso, Brazil. Programa de Pós Graduação em Ecologia, Universidade Federal do Rio de Janeiro (UFRJ), Brazil.
authors: Wilkinson L
authors: WL
authors: Lázaro
authors: Department of Environmental Chemistry, IDÆA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain. Electronic address: cbmqam@cid.csic.es.
authors: Carlos
authors: C
authors: Barata
mesh_terms: D000818:Animals; D003621:Daphnia / Q000187:drug effects*; D004784:Environmental Monitoring; D055868:Floods; D008628:Mercury / Q000633:toxicity; D045483:Rivers / Q000737:chemistry*; D013030:Spain; D053719:Tandem Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Cyanobacteria; Feeding; Mercury; PCB; Toxicity identification evaluation