title: Humic acids increase dissolved lead bioavailability for marine invertebrates.
abstract: The presence of dissolved organic matter (DOM), as humic acids (HA), in natural waters is assumed to decrease dissolved metal bioavailability by binding metal ions and, therefore, decreasing the free ion concentration in solution. In this study, Pb complexation by HA in artificial seawater was checked by means of square wave anodic stripping voltammetry (SWASV). Uptake and toxicity of this metal in the absence and presence of HA was tested using excised gills of Mytilus edulis and the Paracentrotus lividus embryo-larval bioassay respectively. Both Pb uptake by mussel gills and Pb toxicity to sea urchin larvae increased in the presence of HA, and this increase was higher at higher HA concentrations. Since it is shown that the presence of DOM can enhance the uptake and toxicity of lead in some important marine invertebrate species, these results challenge the general applicability of the free ion activity and related models used for deriving environmental water quality criteria for metals.
authors.affiliation: Departamento de Ecoloxía e Bioloxía Animal, Fac. Ciencias do Mar, Universidade de Vigo, Crta. Colexio Universitario s/n. E-36310 Vigo, Spain. paulasanchez@uvigo.es
authors.forename: Paula
authors.initials: P
authors.lastname: Sánchez-Marín
authors.forename: J Ignacio
authors.initials: JI
authors.lastname: Lorenzo
authors.forename: Ronny
authors.initials: R
authors.lastname: Blust
authors.forename: Ricardo
authors.initials: R
authors.lastname: Beiras
mesh_terms: D000818:Animals; D001681:Biological Assay; D001682:Biological Availability; D004625:Embryo, Nonmammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D006812:Humic Substances; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007854:Lead / Q000493:pharmacokinetics* / Q000633:toxicity; D049880:Mytilus edulis / Q000187:drug effects / Q000378:metabolism*; D047328:Paracentrotus / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D012044:Regression Analysis; D012623:Seawater; D012995:Solubility / Q000187:drug effects; D012996:Solutions; D018675:Toxicity Tests
chemical_list: D006812:Humic Substances; D012996:Solutions; D007854:Lead