Many consumer products containing ZnO have
raised concern for safety in regard to environmental
impact and the public health. Widely used sunscreens for
protecting against UV and avoiding sunburns represent a
great exposure to nano-ZnO, one of the ingredients
commonly applied in sunscreens. Applying nanoproducts
on beaches may release nanoparticles unintentionally into
the ocean. Despite the accumulation of such nanoproducts
in the ocean harming or being detrimental to critical
marine organisms, few studies have investigated the
release and potential toxicity of nanoparticles extracted
from products and compared them with those from
industrial-type nanoparticles. Results show that the cytotoxicity
of both industrial- and sunscreen-derived nano-
ZnO to the marine diatom algae,
Thalassiosira pseudonana
,
increased as exposure increases over time, as
measured by growth inhibition (%) of the algae at a
constant concentration of nano-ZnO (10 mg/L). The
extent of toxicity appeared to be higher from industrialtype
nano-ZnO compared with sunscreen-extracted nano-ZnO, though the extent becomes similar when
concentrations increase to 50 mg/L. On the other hand, at
a fixed exposure time of 48 h, the cytotoxicity increases
as concentrations increase with the higher toxicity shown
from the industrial-type compared with sunscreen-induced
nano-ZnO. Results indicate that while industrial-type
nano-ZnO shows higher toxicity than sunscreen-derived
nano-ZnO, the release and extent of toxicity from nano-
ZnO extracted from sunscreen are not trivial and should
be monitored for the development of safe manufacturing
of nanomaterials-induced products.
