title: A macroalgae-based biotechnology for water remediation: Simultaneous removal of Cd, Pb and Hg by living Ulva lactuca.
abstract: Metal uptake from contaminated waters by living Ulva lactuca was studied during 6 days, under different relevant contamination scenarios. In mono-metallic solutions, with concentrations ranging from 10 to 100 μg L-1for Hg, 10-200 μg L-1for Cd, and 50-1000 μg L-1for Pb, macroalgae (500 mg L-1, d.w.) were able to remove, in most cases 93-99% of metal, allowing to achieve water quality criteria regarding both surface and drinking waters. In multi-metallic solutions, comprising simultaneously the three metals, living macroalgae still performed well, with Hg removal (c.a. 99%) not being significantly affected by the presence of Cd and Pb, even when those metals were in higher concentrations. Removal efficiencies for Cd and Pb varied between 57 and 96%, and 34-97%, respectively, revealing an affinity of U. lactuca toward metals: Hg > Cd > Pb. Chemical quantification in macroalgae, after bioaccumulation assays demonstrated that all Cd and Hg removed from solution was really bound in macroalgae biomass, while only half of Pb showed to be sorbed on the biomass. Overall, U. lactuca accumulated up to 209 μg g-1of Hg, up to 347 μg g-1of Cd and up to 1641 μg g-1of Pb, which correspond to bioconcentration factors ranging from 500 to 2200, in a dose-dependent accumulation. Pseudo-first order, pseudo-second order and Elovich models showed a good performance in describing the kinetics of bioaccumulation, in the whole period of time. In the range of experimental conditions used, no mortality was observed and U. lactuca relative growth rate was not significantly affected by the presence of metals. Results represent an important contribution for developing a macroalgae-based biotechnology, applied for contaminated saline water remediation, more "green" and cost-effective than conventional treatment methods.
authors.affiliation: CESAM & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental, Rua dos Bragas 289, 4050-123, Porto, Portugal. Electronic address: brunogalinho@ua.pt.
authors.forename: Bruno
authors.initials: B
authors.lastname: Henriques
authors.affiliation: LAQV/REQUIMTE, Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465, Porto, Portugal.
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Rocha
authors.affiliation: CIIMAR, Interdisciplinary Centre of Marine and Environmental, Rua dos Bragas 289, 4050-123, Porto, Portugal; CICECO & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Cláudia B
authors.initials: CB
authors.lastname: Lopes
authors.affiliation: CESAM & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Figueira
authors.affiliation: CESAM & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: A C
authors.initials: AC
authors.lastname: Duarte
authors.affiliation: CIIMAR, Interdisciplinary Centre of Marine and Environmental, Rua dos Bragas 289, 4050-123, Porto, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vale
authors.affiliation: CEF & Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
authors.forename: M A
authors.initials: MA
authors.lastname: Pardal
authors.affiliation: CESAM & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: E
authors.initials: E
authors.lastname: Pereira
mesh_terms: D001709:Biotechnology; D002104:Cadmium / Q000378:metabolism; D007854:Lead; D019216:Metals, Heavy; D012624:Seaweed / Q000378:metabolism*; D044445:Ulva; D014867:Water; D014874:Water Pollutants, Chemical
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D007854:Lead
keywords: Bioaccumulation kinetics; Growth rate; Marine macroalgae; Metal removal; Water remediation