10.1021/acs.est.6b01215.s001
Mengting Li
Mengting
Li
Zhuanxi Luo
Zhuanxi
Luo
Yameng Yan
Yameng
Yan
Zhenhong Wang
Zhenhong
Wang
Qiaoqiao Chi
Qiaoqiao
Chi
Changzhou Yan
Changzhou
Yan
Baoshan Xing
Baoshan
Xing
Arsenate
Accumulation, Distribution, and Toxicity
Associated with Titanium Dioxide Nanoparticles in <i>Daphnia
magna</i>
American Chemical Society
2016
uptake
subcellular distribution
Arsenate Accumulation
BDM
accumulation
toxicity
Daphnia magna
signal intensities
Daphnia magna Titanium dioxide nanoparticles
bioavailability
MSF
concentration
Toxicity Associated
consumer products
Titanium Dioxide Nanoparticles
2016-08-02 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Arsenate_Accumulation_Distribution_and_Toxicity_Associated_with_Titanium_Dioxide_Nanoparticles_in_i_Daphnia_magna_i_/3578067
Titanium dioxide
nanoparticles (nano-TiO<sub>2</sub>) are widely
used in consumer products. Nano-TiO<sub>2</sub> dispersion could,
however, interact with metals and modify their behavior and bioavailability
in aquatic environments. In this study, we characterized and examined
arsenate (As(V)) accumulation, distribution, and toxicity in Daphnia magna in the presence of nano-TiO<sub>2</sub>. Nano-TiO<sub>2</sub> acts as a positive carrier, significantly
facilitating D. magna’s ability
to uptake As(V). As nano-TiO<sub>2</sub> concentrations increased
from 2 to 20 mg-Ti/L, total <i>As</i> increased by a factor
of 2.3 to 9.8 compared to the uptake from the dissolved phase. This
is also supported by significant correlations between arsenic (<i>As</i>) and titanium (<i>Ti</i>) signal intensities
at concentrations of 2.0 mg-Ti/L nano-TiO<sub>2</sub> (<i>R</i> = 0.676, <i>P</i> < 0.01) and 20.0 mg-Ti/L nano-TiO<sub>2</sub> (<i>R</i> = 0.776, <i>P</i> < 0.01),
as determined by LA-ICP-MS. Even though <i>As</i> accumulation
increased with increasing nano-TiO<sub>2</sub> concentrations in D. magna, As(V) toxicity associated with nano-TiO<sub>2</sub> exhibited a dual effect. Compared to the control, the increased <i>As</i> was mainly distributed in BDM (biologically detoxified
metal), but <i>Ti</i> was mainly distributed in MSF (metal-sensitive
fractions) with increasing nano-TiO<sub>2</sub> levels. Differences
in subcellular distribution demonstrated that adsorbed As(V) carried
by nano-TiO<sub>2</sub> could dissociate itself and be transported
separately, which results in increased toxicity at higher nano-TiO<sub>2</sub> concentrations. Decreased As(V) toxicity associated with
lower nano-TiO<sub>2</sub> concentrations results from unaffected <i>As</i> levels in MSFs (when compared to the control), where
several <i>As</i> components continued to be adsorbed by
nano-TiO<sub>2</sub>. Therefore, more attention should be paid to
the potential influence of nano-TiO<sub>2</sub> on bioavailability
and toxicity of cocontaminants.