Metal enrichment of PM2.5 from industrial activities

The roles of TRI and regional geochemistry in particulate composition studies

Shiprock, NM

Cristina González-MadduxInstitute for Tribal Environmental ProfessionalsNorthern Arizona University

Overview

Background Mining impacts on surficial composition Other industrial influences and TRI queries Dust and particulate matter Human health concerns

Research Project 1: Shiprock, New Mexico – fine particulate study, focus

on enrichment factor Project 2: Fry Canyon, Utah – mine waste bioaccessibility Summary

Mining in the Four Corners states

Uranium reserves in the Four Corners: Northern Arizona, Marysvale, Paradox Basin, Sand Wash, Front Range, Tallahassee Creek, Marshall Pass, Grants Mineral Belt

Of ~4,000 mine site proxies in the USGS MAS/MILS database, ~3,000 are located in the Four Corners states Map source: Uranium Location Database

Compilation. Technical Report EPA-402-R-05--009.

Mine site abandonment

“The Navajo Abandoned Mine Lands Reclamation Program (NAMLRP) identified more than 1,032 abandoned uranium mine sites. As of 2005, 913 sites have been reclaimed (p. 224).”

- US EPA TENORM Technical Report, Vol. 1 (2006)

Uranium mine waste

Overburden Protore Barren or waste rock Drill cuttings Waste treatment sludge

Sources of windblown dust

Underground and surface mines: Waste rock (overburden pile) Protore piles Ore stockpiles

Wind erosion of mine products and waste

Tailings dam 1973 Heap-leach pile 2010, (abandoned in 1968)

Mine proximity to human communities

EPA calculations based on 2000 U.S. Census data and the Basins MAS/MILS database

StatePopulation

(within 5 miles of an AUM)

Arizona 12,160

New Mexico 84,869

Colorado 518,357

Utah 22,376

Total 637,762

Toxics release inventory

TRI chemical release reports were reviewed for metals emissions in order to establish potential local or regional industrial influences on enrichment

Fugitive and point source industrial air emissions were compiled for both San Juan County, New Mexico as well as for all surrounding counties: Rio Arriba County, NM, Sandoval County, NM,

McKinley County, NM, Montezuma County, CO, La Plata County, CO, Apache County, AZ, and San Juan County, UT.

Coarse dust v. particulate matter

Particulate and soil dust composition

Average mass conc. in PM2.5 (µg/m3)

Sulfates

Organics

Elemental carbon

Nitrates

Soil Dust

Primarily soil dust constituents: Al, Si, S, K, Ca, Fe

Trace metals also present

Particle toxicity

Human exposure pathways

Deleterious metals associated with uranium mine waste vanadium (V), copper (Cu), arsenic (As), uranium (U), other trace elements and trace metals (Sb, Se, Pb, Cr, Zn)

Human exposure pathways Ingestion Inhalation Dermal penetration

Chemical toxicity

The health effects associated with oral or dermal exposure to natural and depleted uranium appear to be solely chemical in nature and not radiological, while those from inhalation exposure may also include a slight radiological component, especially if the exposure is protracted.

- ATSDR toxicological profile for uranium, May 2011

Project 1: Shiprock, NMComposition of fine particulate matter (PM2.5) downwind of AUMs

Field location

Research goals

Collect samples of PM2.5 dust downwind of AUMs Identify metals in PM2.5

Compare observed and expected concentrations using enrichment factor [EF] analysis

Methods: sample collection

Collection 10 samples collected over 3 months (2009

and 2010) PM2.5 monitor (Met One) Teflon filters (47mm) 96 h/sample 37 m3 of air sampled per filter (6.7 LPM)

Analysis Gravimetric (± 0.1 ng) XRF spectrometry – major soil elements

(Chester LabNet) ICP-MS – trace metals (ASU)

Methods: TRI survey for local industrial emissions

1

2

3

4

5

6, 7Air sampling location

UMTRA site

Climax Transfer Station

1. Four Corners Generating Station, APS – coal fired power plant; 2. BHP Navajo Coal Co. – coal mining operation; 3. BHP Navajo Coal Co. – coal mining operation; 4. San Juan Refining Co. (A.K.A. Western Refining SW) – petroleum refinery; 5. Coastal Chemical Co., L.L.C. – chemical manufacturer (incl. petrochemicals); 6. San Juan Coal Co., San Juan Mine – coal mining operation; 7. San Juan Generating Station, PNM – coal fired power plant.

Toxics Release Inventory results

Industry key: EU = electric utilities, CM = coal mining, P = petroleum, SCG = Stone/Clay/Glass

A Combined results for San Juan county, NM and all surrounding counties: Rio Arriba county, NM, Sandoval county, NM, McKinley county, NM, Apache county, AZ, San Juan county, UT, Montezuma county, CO and La Plata county, CO.B Includes pounds of toxins released for both elemental compounds and element.

Results: PM2.5 concentration

Average concentration 10 µg/m3

U.S. EPA 24-h fine particulate standard 35 µg/m3

Results: Elemental composition

6 soil elements were most abundant: Al, Si, S, K, Ca, Fe (range 0.1-1.0 µg/m3)

24 trace metals were detected (0.1-14 ng/m3) 11 trace elements were enriched in both major

sampling periods (Winter 2009, 2010)

Enrichment Factor analysisEF (X) = ([Xsample /Alsample] / [Xcrust/Alcrust])

Results: Enriched elements

Element Max EF Potential sources

AUM Mining Industry

Selenium (Se) 37,632 ✔ ✔

Bromine (Br) 3,113 ✔

Sulfur (S) 1,704 ✔

Antimony (Sb) 1,314 ✔ ✔

Boron (B) 881 ✔

Bismuth (Bi) 655 ✔ ✔

Tin (Sn) 500 ✔ ✔

Cadmium (Cd) 381 ✔

Nickel (Ni) 189 ✔

Lead (Pb) 81 ✔ ✔

Copper (Cu) 52 ✔ ✔

Zinc (Zn) 44 ✔ ✔

Slightly enriched or not enriched

Element Max EF Possible sourcesAUMs Mining Assoc. Industry

Uranium (U) 18 ✔ ✔

Cobalt (Co) 13 ✔

Barium (Ba) 9 ✔ ✔

Vanadium (V) 6 ✔ ✔

Manganese (Mn) 5 ✔

Strontium (Sr) 2 ✔

Beryllium (Be) 2 ✔ ✔

Shiprock Conclusions

San Juan County (NM) airshed is burdened by enriched concentrations of several deleterious and toxic metals

Federal particulate standards were not exceeded at any point during the study

Probable contribution to toxic metal enrichment from industrial sources

No data to definitively link AUM metals to fine particulate composition (additional research needed to evaluate)

Summary

Shiprock served as excellent study site It is subject to regional air quality issues that may

have human health implications based metal enrichment in fine particulate

Additional research is required to determine the true airshed burden from abandoned and active mine sites Air dispersion modeling Isotopic analysis Currently investigating the role of mining interference factor