Bioaccumulation of silver in Daphnia magna: Waterborne and dietary exposure to nanoparticles and dissolved silver.
Silver nanoparticles (Ag-NP) are incorporated into commercial products as antimicrobial agents, which potentiate their emission to the environment. The toxicity of Ag-NP has been associated with the release of Ag ions (Ag+), which are more toxic to aquatic organisms than Ag-NP. In this study, a toxicokinetics approach was applied to compare the potential of Daphnia magna to accumulate Ag from either Ag-NP or AgNO3through different exposure routes: a) water, b) diet and c) water and diet. A one-compartment kinetics model was applied to describe the development of Ag body concentrations over time and derive uptake (k1w;k1d) and elimination (k2) rate constants. Under water-only exposure, AgNO3induced higher Ag uptake rate constants and bioconcentration factors when compared to Ag-NP. For dietary exposure, no differences in Ag concentrations in D. magna, along with the kinetics parameters, were found for both Ag forms. Simultaneous water and dietary exposures to Ag-NP induced higher Ag concentrations in D. magna compared to AgNO3. In this combined exposure, uptake from water explains most for the increase in Ag body concentration in D. magna for Ag-NP exposure, whereas uptake from the diet was the major contributor for the increase in Ag concentration in D. magna under AgNO3exposure. Biomagnification was not observed for any of the exposure routes applied in this study, neither for Ag-NP nor for AgNO3.
Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-093 Aveiro, Portugal. Electronic address: ribeiro.f@ua.pt.
Fabianne
F
Ribeiro
Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Cornelis A M
CAM
Van Gestel
Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-093 Aveiro, Portugal.
Maria D
MD
Pavlaki
Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-093 Aveiro, Portugal.
Sofia
S
Azevedo
Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-093 Aveiro, Portugal.
Amadeu M V M
AMVM
Soares
Department of Biology & CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-093 Aveiro, Portugal.
Susana
S
Loureiro
D000818:Animals; D003621:Daphnia / Q000378:metabolism*; D000074341:Dietary Exposure; D053768:Metal Nanoparticles / Q000032:analysis*; D012834:Silver / Q000493:pharmacokinetics*; D012835:Silver Nitrate / Q000493:pharmacokinetics; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics*
D014874:Water Pollutants, Chemical; D012834:Silver; D012835:Silver Nitrate
Bioaccumulation; Daphnia magna; Dietary exposure, trophic transfer; Silver nanoparticles