Table 2: Mean values of zetapotential (of six replicates) for different nanomaterials dispersed in various media. DI water + 5 mM NaCl—this medium was employed to compare with the DI results when in the presence of inert background electrolyte. Values are the mean and ±1 SD of six replicates.

Sample nameDI water (mV)DI water + 5 mM NaCl (mV)Fish medium (mV)Seawater (mV)Daphnia medium (mV)

Nanograin CeO233.0 ± 2.033.9 ± 1.7−11.1 ± 1.0N/A1.2 ± 0.2
Nanosun ZnO24.6 ± 0.425.2 ± 0.612.4 ± 0.3N/A4.9 ± 0.2
Micron ZnO20.2 ± 0.413.9 ± 0.64.4 ± 0.4N/A−4.6 ± 0.4
Z-COTE ZnO24.3 ± 0.420.8 ± 0.810.8 ± 0.1N/A1.3 ± 0.2
Micron CeO2−7.0 ± 6.0−2.0 ± 2.0−22.3 ± 0.5N/A−15.0 ± 0.3
Ceria Dry CeO228.0 ± 2.023.0 ± 1.3−15.3 ± 0.6N/A−17.4 ± 0.3