Generating allometric scaling relationships for aquatic species and metallic nanomaterials using nano-QSARs

Species traits differ between organisms and result in variable sensitivity towards contaminants. Body size is regarded as a "master trait" as it correlates and scales with several internal processes within organisms such as their metabolic rate. Smaller-sized species typically have higher metabolic and uptake rates and thus tend to be more sensitive to contaminants. While the correlation between body size and toxicity has been investigated previously, this is in its infancy for engineered nanomaterials (ENMs). This study investigates size-dependent scaling relationships between different species groups and the toxicity of metallic ENMs. Nano-QSARs were used to generate data that mimic controlled laboratory experiments, which are subsequently fitted to statistical models. Results indicated that the toxicity of ENMs scales linearly with body size, whereby smaller-sized species (crustaceans and phytoplankton) were generally more sensitive. Size-dependent scaling relationships have the potential to enable informed extrapolation across species when toxicity data are limited. This can assist in prioritizing the generation of experimental data, potentially reducing the necessity for further animal testing.