Effect of titanium dioxide nanoparticles on copper toxicity to Daphnia magna in water: Role of organic matter.
Inevitably released into natural water, titanium dioxide nanoparticles (nano-TiO2) may affect the toxicity of other contaminants. Ubiquitous organic matter (OM) may influence their combined toxicity, which has been rarely reported. This study investigated the effect of nano-TiO2on Cu toxicity to Daphnia magna and the role of OM (dissolved or particle surface bound) in inducing combined effects. The effect of nano-TiO2on heavy metal accumulation depended on the adsorption capacity for heavy metals of nano-TiO2and the uptake of nano-TiO2-metal complexes by organisms. Nano-TiO2significantly decreased Cu accumulation in D. magna, but the reducing effect of nano-TiO2was eliminated in the presence of humic acid (HA, a model OM). In the Cu and HA solution, nano-TiO2slightly affected the bioavailability of Cu2+and Cu-HA complexes and thus slightly influenced Cu toxicity. The nanoparticle surface-bound HA reduced the effect of nano-TiO2on the speciation of the accumulated Cu; therefore, the combined effects of nano-TiO2and Cu on biomarkers similarly weakened. HA-altered Cu speciation may be the main factor responsible for the influence of HA on the combined effects of nano-TiO2and Cu. This study provides insights into the combined effects of nano-TiO2and heavy metals in natural water.
Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China. Electronic address: fanwh@buaa.edu.cn.
Wenhong
W
Fan
Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
Ruishuang
R
Peng
Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
Xiaomin
X
Li
Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
Jinqian
J
Ren
Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
Tong
T
Liu
Department of Environmental Science and Engineering, School of Space and Environment, Beihang University, Beijing 100191, PR China.
Xiangrui
X
Wang
D000818:Animals; D003300:Copper / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects*; D006812:Humic Substances; D053758:Nanoparticles / Q000633:toxicity; D014025:Titanium / Q000494:pharmacology; D014867:Water / Q000494:pharmacology; D014874:Water Pollutants, Chemical / Q000633:toxicity
D006812:Humic Substances; D014874:Water Pollutants, Chemical; D014867:Water; D003300:Copper; D014025:Titanium
Aquatic organisms; Heavy metals; Organic matter; Titanium dioxide nanoparticles; Toxicity