Environmental Engineering Reference
In-Depth Information
Acute toxic effects have been observed in
Daphnia magna
and
Thamnocephalus
platyurus
after being treated with nano TiO
2
. Of the total
D. magna
cells exposed to a
20 mg/L concentration, 60% showed toxic effects, whereas marginal toxic effects
were observed in
T
.
platyurus
after exposure to nano TiO
2
(Table
5
)(Baunetal.
2008
).
D. magna
,
T. platyurus
and
Tetrahymena thermophila
were tested for toxic
responsestometaloxidenanoparticles(ZnOandCuO),inbothnaturalandartiicial
waters(Blinovaetal.
2010
; Table
5
). In natural waters, the toxicity to crustaceans
tonanoCuO(90-224mg/L)wastenfoldlower(basedonLC
50
values) than for the
bulkCuOcounterpart.LC
50
values for ZnO nano forms were lower than those of
CuOnano-andbulk-particles.However,innaturalwater,thetoxicitywasdepen-
dentondissolvedorganiccarbon(DOC)content(Blinovaetal.
2010
).
The acute toxicity of TiO
2
(6 nm),Al (100 nm),ALEX (aluminum explosive)
nanoparticles coated with Al
2
O
3
, L-ALEX-NPs coated with carboxylate groups, and
boronnanoparticles(10-20nm)wastestedon
Daphnia magna
and
Vibrio fischeri
(Striguletal.
2009
). TiO
2
and L-ALEX displayed low toxicity to
D. magna
. The
LD
50
(48h)valuesforTiO
2
and L-ALEX NPs in
D. magna
were107.88mg/Land
7.483mg/L,respectively.Thisstudyprovedthatnano-aluminiumismoretoxicthan
its bulk counterparts (Table
5
). Concentrations of boron nanoparticles (56 and
66mg/L)weretoxicto
V. fischeri
(Striguletal.
2009
). Boron, however, was slightly
more toxic acutely to
D. magna
; LD
50
24-, and 48-h LD
50
valueswere19.5mg/L
and6.7mg/L,respectively(Table
5
). The authors of this study concluded that boron
nanoparticlesaretoxictoaquaticorganisms(Striguletal.
2009
). Lovern and Klaper
(
2006
) conducted an acute toxicity test for 48 h with C
60
and TiO
2
nanoparticles on
D. magna
. Results were that a concentration-dependent increase in mortality was
observed(Table
5
).However,fullerene(C
60
) showed greater toxicity at a lower con-
centration(LovernandKlaper
2006
).
Mollusca
TheCdTeQDselicitedsublethaleffectsinthefreshwatermussel
Elliptio compla-
nata
,after24hofexposure(Gagneetal.
2008
). Effects on hemocytes and immu-
nocompetencewereobservedintherangeof1.6-8mg/LfortheseCdTeQDs.Also
notedbytheauthorswereoxidativestressingillsanddigestiveglands(Table
5
). A
signiicantreductioninDNAstrandbreakswasobservedintheconcentrationrange
of4and8mg/L(Gagneetal.
2008
).
Nematodes
Caenorhabditis elegans
is the nematode most commonly used for toxicity testing of
nanoparticles.Wangetal.(
2009
)evaluatedthetoxicityofbothnanoandbulkforms
of ZnO, Al
2
O
3
and TiO
2
in
C. elegans
. Results were that LC
50
values for ZnO nano
andbulkformswerethesame(2.3mg/L).However,LC
50
values for Al
2
O
3
and TiO
2
bulkformsweretwicethatofthenanoforms,meaningtheywereonlyhalfastoxic
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