title: Joint Toxicity of Cadmium and Ionizing Radiation on Zooplankton Carbon Incorporation, Growth and Mobility.
abstract: The risk of exposure to radioactive elements is seldom assessed considering mixture toxicity, potentially over- or underestimating biological and ecological effects on ecosystems. This study investigated how three end points, carbon transfer between phytoplankton and Daphnia magna, D. magna mobility and growth, responded to exposure to γ-radiation in combination with the heavy metal cadmium (Cd), using the MIXTOX approach. Observed effects were compared with mixture effects predicted by concentration addition (CA) and independent action (IA) models and with deviations for synergistic/antagonistic (S/A), dose-level (DL), and dose-ratio (DR) dependency interactions. Several patterns of response were observed depending on the end point tested. DL-dependent deviation from the IA model was observed for carbon incorporation with antagonism switching to synergism at higher doses, while the CA model indicated synergism, mainly driven by effects at high doses of γ-radiation. CA detected antagonism regarding acute immobilization, while IA predicted DR-dependency. Both CA and IA also identified antagonism for daphnid growth. In general, effects of combinations of γ-radiation and Cd seem to be antagonistic at lower doses, but synergistic at the higher range of the doses tested. Our results highlight the importance of investigating the effects of exposure to γ-radiation in a multistressor context.
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University , Stockholm 106 91, Sweden.
authors.forename: Francisco J A
authors.initials: FJ
authors.lastname: Nascimento
authors.affiliation: Centre for Ecology and Hydrology , Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB, United Kingdom.
authors.forename: Claus
authors.initials: C
authors.lastname: Svendsen
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University , Stockholm 106 91, Sweden.
authors.forename: Clare
authors.initials: C
authors.lastname: Bradshaw
mesh_terms: D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D002244:Carbon / Q000378:metabolism; D003621:Daphnia; D020387:Food Chain; D005720:Gamma Rays / Q000009:adverse effects*; D058086:Microalgae; D008962:Models, Theoretical; D010839:Phytoplankton; D015048:Zooplankton / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects*
chemical_list: D002104:Cadmium; D002244:Carbon