Transport and bioavailability of U and co-occurring metals in nanoparticulate matter on tribal lands affected by mining legacy

PROJECT 2 - ENVIRONMENTAL PROJECT 2 – ESE Particulate (ESE PM) - PROJECT SUMMARY
Abandoned uranium mines (AUM) situated on the tribal lands of the Navajo Nation and Laguna pueblo
represent a major source of environmental contamination that threatens public health as a result of
mobilization of toxic metals mixtures bearing uranium (U), vanadium (V), copper (Cu), arsenic (As). The
transport of toxic metals mixtures into the air in nanoparticulate form, and the subsequent potential for
inhalational and ingestion exposures, has never been investigated in a rigorous manner. The proposed
research will investigate the potential exposure hazards to toxic metals mixtures in nanoparticulates resulting
from inhalation and ingestion via contaminated agricultural crops from AUM sites located on Navajo Nation and
Laguna Pueblo tribal lands in Arizona and New Mexico. The project will address the two specific aims:
1) Understanding the physicochemical characteristics and distribution of metals mixtures in a range of
environmental samples, including mine wastes, soils (agricultural and background) and airborne particulates
around AUM and modelling their transport and deposition by wind into neighboring communities; 2) Assessing
the uptake of metals into plants on agricultural soils adjacent to abandoned mine sites to understand if airborne
metals-bearing particulates present a potential exposure risk. and 3) understanding the mechanisms of
particulate assimilation into agricultural crops through their root and folial system through experimental
stDeveloping a process model for the resuspension and transport of metal-bearing PM from AUM sites to
estimate exposure risks for nearby vulnerable communities. For the process model, we will a) ascertain the
particle size distributions and mineralogic characteristics of metal-bearing PM originating from AUM sites and
the exposure potential to vulnerable populations living in the regional airshed under varied meteorological
conditions; and b) conduct source-receptor modeling for the region, integrating information from three
performance sites and deriving long-term estimates for Navajo community members. The proposed research
will utilize state-of-the-art monitoring, chemical, imaging and atmospheric modeling techniques to provide a
comprehensive dataset on the concentrations, speciation, valence, solubility, etc., of ultrafine-grained PM
nanoparticle scale that are essential to evaluate the potential toxicity and inhalation exposure risk for PM. The
results will reduce uncertainty regarding the metal content, exposure concentrations, and sources of AUM-
related PM exposures in risk reduction strategies.

Grant Number: 4P42ES025589-09
NIH Institute/Center: NIH
Principal Investigator: Adrian Brearley