TĪNĒ: the fate, behavior, and ecotoxicology of manufactured nanomaterials in terrestrial ecosystems

We have developed a life cycle perspective inspired conceptual model (CM) that indicates terrestrial ecosystems as a major repository for ZnO, TiO2, and Ag manufactured nanomaterials (MNMs) introduced via the land application of MNM-containing biosolids. In this project we are investigating the transport, fate, behavior, bioavailability, and effects of MNMs in(to) agroecosystems under environmentally realistic scenarios organized around three key hypotheses: Hypothesis (H1) Surface chemistry is the primary factor influencing the fate and transport of MNMs in the terrestrial environment as well as the bioavailability and effects to biological receptors; Hypothesis (H2) Once released to the environment, pristine MNM surfaces will be modified by interactions with organic and inorganic ligands (macromolecules) or via other biogeochemical transformations (aging effects forming a-MNMs); Hypothesis (H3) Ecoreceptors will respond to interactions with pristine metal and metal oxide MNMs, a-MNMs, and/or dissolved constituent metal ions and bulk oxides by specific ecological and toxicogenomic responses that will reflect their combined effects. The overall objectives are to: O1) Compare the transport, fate, behavior, bioavailability, and effects of MNMs, a- MNMs, and/or dissolved free metals/bulk oxides to organisms with key terrestrial ecosystem functions, as well as exposure pathways involving humans; O2) Determine MNM, surface modified MNM and a-MNM interactions with important biological targets relevant to the BLM and pBRM models and relate these interactions to physicochemical properties; O3) Validate models with information generated from experiments designed to address O1 for MNMs introduced through a pilot scale Waste Water Treatment Process (WWTP) to key terrestrial ecoreceptors, including effects of MNMs on the WWTP itself; O4) Determine realistic MNM emission scenarios for Tier 1 MNMs in wastewater from the WWT pilot plant data and develop first generation Life-Cycle-Analysis-inspired Risk Assessment (LCA-RA) model components for terrestrial effects of Tier 1 MNMs and a-MNMS based on data generated in experiments designed to address O1, O2, & O3; and O5) Provide tools for in situ detection, monitoring, and characterization of pristine MNMs and a-MNMs in environmental media and biota. The key results from aging and toxicity studies will be presented.