Date post: | 28-Dec-2015 |
Category: |
Documents |
Upload: | pamela-turner |
View: | 216 times |
Download: | 0 times |
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)
Sources of windblown dust
Underground and surface mines: Waste rock (overburden pile) Protore piles Ore stockpiles
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.
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
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
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