A short overview of the toxicity is shown in Table 2.
The TiO2 nanomaterials were available as dry powder. The results are presented as
mg TiO2/kg or mg TiO2/L. Silver was available as dispersion. Further to the total concentration of silver the concentrations of Ag ions in soil and sediment were determined via DGT
(diffusive gradient in thin films). The results are presented as nominal concentrations and as
Ag
+
concentration. The gold concentration measured in NM-330 was lower than the value
reported by the producer (expected: 0.01% corresponding to 100 mg/L; measured 43.8
mg/L). The NIST reference material 8011 (gold nanoparticles, nominal diameter 10 nm) was
analysed along with the samples of the test; recovery amounted to about 100%. The recovery of the applied standard Au solution was about 100% as well. As details on the analytical
method used by the producer of NM-330 are not known, the discrepancy between the results
cannot be explained. Due to the discrepancy between measured and communicated values,
the concentrations of the ecotoxicological analyses are presented as % NM-330 (v/v) in the
test suspension.