Fate and Toxicity of Engineered Nanomaterials in the Environment: a Meta-analysis

Engineered nanomaterials (ENMs, particles less than 100 nanometers) are being manufactured at increasing levels for a variety of reasons including cosmetics, food packaging and preservation, fertilizers, and medical technology. Thousands of metric tons of ENMs are released to soils, water bodies, air, and landfills each year. These particles have distinct properties owing to their small size and relatively large surface area to volume ratio. These characteristics can result in these materials having higher reactivity and toxicity in biological systems - especially because ENMs are small enough to enter cells. However, studies on environmental and ecological effects of ENMs have shown mixed results. The goal of this project is to address three primary research questions using meta-analysis of existing literature: 1) Which ENMs have been studied and in what context? 2) How do particle identity, size, concentration, and study duration influence toxicity (as estimated by response ratios, lethal concentration (LC50), and effective concentration (EC50)) in different organisms related to the role they play in the environment? 3) What are bioaccumulation, biomagnification, and bioconcentration factors of ENMs as a function of ecosystem role and trophic level in different organisms? We collected data from 191 published scientific papers and extracted 2102 unique observations that are used to address the questions outlined above. We calculated response ratios related to biological responses of biomass, diversity, growth, metabolism, and survival to evaluate how these are influenced by ENM exposure. Values of LC50 (concentration at which 50% of test organisms died) and EC50 (concentration at which 50% of test organisms showed an effect) were collected to estimate concentrations at which toxicity occurs. Bioaccumulation (BAF), bioconcentration (BCF), and biomagnification (BMF) factors were recorded to estimate environmental accumulation and trophic transfer. This work is a resu