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