Abstract:
Studies were conducted to determine the effects of a panel of seven nanomaterials (NMs), namely:
a-alumina, g-alumina, precipitated silica; silica fume, calcined silica fume, colloidal antimony pentoxide
(Sb2O5), and superfine amorphous ferric oxide (Fe2O3), on sediment dwelling invertebrates Chironomus
tentans under controlled laboratory conditions. Percentage survival, enzyme activities, growth development,
and DNA fragmentation parameters were studied as acute, biochemical, and physiological
toxicities of NMs, respectively. Quantitation of catalase and peroxidase enzyme activity demonstrated
that toxicant stress of the NMs increased enzyme activity in a concentration dependent fashion across all
treatments. The percentage growth length of the test specimens exposed to different NMs was
significantly reduced compared to the negative control while only five concentrations were not in the
toxic range, namely; Fe2O3 (5 mg/kg); silica fume (5 mg/kg, 50 mg/kg); Sb2O5 (5 mg/kg) and calcined silica
fume (5 mg/kg). Genotoxic stress assessed by use of DNA laddering showed complementary findings to the
other ecotoxicological endpoints tested in this study—the percentage survival and growth length
inhibition.
