Toxicologically important characteristics of atmospheric particulate mineral matter

from diverse sources: a context for understanding potential health

implications of intercontinental dust

Toxicologically important characteristics of atmospheric particulate mineral matter

from diverse sources: a context for understanding potential health

implications of intercontinental dust

Geoffrey S. Plumlee, Ph.D.gplumlee@usgs.gov

Suzette A Morman, Virginia Garrison,Heather A. Lowers, Gregory P. Meeker

U.S. Geological Survey

Phoenix, Arizona Dust storm, July 26, 2011 Photo from http://www.inquisitr.com/wp-content/2011/07/phoenix-arizona-dust-

storm-2011.jpg

PM Sources

Geoanthropogenic AnthropogenicGeogenic

Dry lakebed dusts

Pathogens in dusts

Wildfire ash, smoke

Volcanic ash

Volcanic fog (vog)

Geologic (natural)asbestos

Desert dusts

Urban PM

Commercialasbestos

PM fossil fuel combustion

Dusts from mine wastesWTC dust

Intercontinental dust

Potential acute and chronic health effects of PM

• Particle overload (asthma, cardiovascular)• Physical or chemical irritation • Diseases from contained pathogens• Fibroses (asbestosis, silicosis, etc.), with

secondary heart failure, tuberculosis, etc.)• Cancers (lung cancer, mesothelioma, etc.)• Toxicity effects of contained heavy metals

Toxicity effects of PM depend on• Exposure pathway (ingestion, inhalation, dermal,

ocular) • Intensity and duration of exposure (dose)• Personal factors

– Age– Genetics– Smoker or non-smoker?– General health/nutritional status

• Particle characteristics (mineralogical, chemical, physical)– See summaries:

• Plumlee et al., 2006, Rev. Min. Geoch., v. 64, chapter 2• Plumlee et al., 2007, Treatise on Geochemistry, online version,

vol. 9, Chapter 7

Toxicologically important characteristics of PM• Particle size, shape• Surface characteristics• Biosolubility / biodurability in the body• Toxicant content, bioaccessibility of contained

toxicants • Chemical bioreactivity (causes tissue irritation,

damage) • Redox bioreactivity (causes oxidative stress)• Pathogen content• Radioactivity

PM types, sources we have examined

• Libby, Montana fibrous amphiboles• Asbestos, other fibrous silicates from around the US, world• Dust sources from Owens Lake and other dry(ing) lakebeds• Dusts from the collapse of the World Trade Center• Desert dusts (US desert SW; UAE; Afghanistan)• African dusts collected in Mali, Trinidad-Tobago, USVI• Air-driven ash, residual ash, burned soils from many wildfires

at wildland-urban interface• Ash from many different volcanic eruptions• Coal fly ash; urban particulate matter• Wind-erodable material from mine wastes, tailings• In collaboration with many earth and health scientists

Types of analyses• Inorganic chemical composition (majors, trace elements, C, O,

N, S) • Particle characteristics (size, shape, mineralogy, composition)• Organic chemical composition (PAHs, organohalogens, dioxins,

wastewater indicators, oil components)• Microbial characteristics (specific pathogens, microbial

communities)• Chemical reactivity of materials in rain water, sea water, landfill

leachates• Bioaccessibilty of contaminants in simulated human biofluids

(gastrointestinal, lung, serum, lysosomal)• Others as appropriate

Acknowledgements• USGS: Todd Hoefen, Ray Kokaly, Gregg Swayze, Ginger

Garrison, Brad Van Gosen, Bill Benzel, Harland Goldstein,Rich Reynolds, Bob Finkelman, many others

• Earth scientists outside the USGS: Claire Horwell(U. Durham, IVHHN); Martin Schoonen, Rich Reeder (SUNY Stony Brook), Terry Sobecki (USACE), many others

• Many colleagues in public health: Jose Centeno (DoD NTC); Cecile Rose, Lee Newman (Natl. Jewish Health); Chris Weis, Aubrey Miller (NIEHS); David Prezant(FDNY); Jim Durant, Tony Neri (CDC); John Smith (EPA); Gary Krieger (Newfields); Ed Postlethwait (U Alabama-Birmingham); Capt. Mark Lyles (US Navy War College); Eduardo de Capitani (U Campinas), many others

African dust samples collected in Mali, Trinidad, and US Virgin Islands

USVI

Trinidad

Mali

Garrison et al., 2003, Bioscience 53, 469-479.Garrison et al., 2010, 19th World Congress of Soil Science,

Soil Solutions for a Changing World, 33-36.

Garrison et al., 2003, Bioscience 53, 469-479.Garrison et al., 2010, 19th World Congress of Soil Science,

Soil Solutions for a Changing World, 33-36.

Complex particulate matterDusts from the World Trace Center collapse

Photo by NYPD

500 microns

Slag wool fibers

Concrete

Slag wool sphere

Window glass

50 microns

Chrysotile asbestos fiber

bundle

Slag wool fibers

Concrete Dusts generated by the collapse were a pulverized, complex mixture of glass fibers, concrete particles, wallboard gypsum, window glass fragments, and many other materials used in or used to construct the buildings.

Pb-rich

Birich

The size of geogenic PM

• A commonly stated health (mis?)perception: “Geogenic PM are not sufficiently small in size (ie<2.5 µm) to be inhaled into the deep lungs, and therefore are not as problematic as anthropogenic PM”

Dispelling the misperception• Geo(anthropo)genic dusts can have a significant proportion

of particles in the inhalable, respirable size ranges

A typical day in Kandahar, AfghanistanPhoto by Jared Abraham, USGS

Settled dust samples,

Kandahar AFB, Afghanistan

• Majority of particles are respirable (<3 microns), • Largely geogenic dusts: Clays ( smectite, kaolinite and illite), quartz, iron

oxide, feldspar, dolomite, sodium sulfate, gypsum, calcite, titanium dioxide

SEM photomicrogaph of quartz fiber filter with trapped dust particles from Africa, collected in US Virgin Islands

Suzette Morman, Ginger Garrison, Heather Lowers

25 µm

PM chemical reactions with the bodyThe same mineral will react quite differently along the different exposure pathways

Figure from Plumlee and Ziegler, 2006

Particle biodurability / biosolubility

LibbyAmphibole

African dust,USVI

BiosolubleBiodurable

Crystallinesilica

Erionite

Coal fly ash

Sulfate salts from sulfide oxidation

Lead carbonate (gastric only)

Efflorescent thenardite

image from B. Buck)

Volcanicash

Volcanicglass

Chemically bioreactive PMPM with caustic alkalis:• Dusts from the World Trade Center collapse• Airfall ash, residual white ash from wildfires

Station wildfire, southern California, August, 2009. Photo by Genaro Molina, LA Times

Holden Mine, WA, USA, US Forest Service photo,pre-remediation

http://www.fs.fed.us/r6/wenatchee/holden-mine/

Chemically bioreactive PM• Acid sulfate salts in weathered mine wastes

and tailings

Content, bioaccessibility of metal toxicantsCoal fly ashMine tailings with tertiary soluble salts

Artisanal remining of lead-zinc ores, Kabwe, Zambia

Arstisanal processing of lead-rich gold ores, Nigeria

Dusts from dry(ing) lake beds

• Physiologically based extraction tests with simulated body fluids indicate that dry lake dusts can have quite high levels of bioaccessible metalloids

• Arsenic, chromate, tungsten, uranium, molybdenum

Owens Dry Lake, California

Hexavalent chromium is present inresidential and some wildland wildfire ash• Somewhat soluble in water leaches• Somewhat bioaccessible and persistent in

simulated lung fluid leaches

African dusts: As, Cd are quite bioaccessible in simlung, gastric; bioaccessibility increases downwind

As µg/g Lung Gastric Cd µg/g Lung Gastric

Mali 627 8 <LOQ 38 0.3 <LOQ 50

Mali 623 7 <LOQ <LOQ 0.3 16 63

Mali 001 7 <LOQ 83 0.5 31 71

Mali 005 6 12 25 0.3 12 88

Mali 009 6 40 19 0.5 21 86

Mali 016 7 <1 43 0.7 15 69

Mali 605 6 15 68 0.3 22 80

Trinidad 629 4 <LOQ 100 0.2 <LOQ 100

Trinidad 634 6 100 100 0.4 <LOQ 73

Trinidad 646 5 100 100 0.4 <LOQ 62

USVI 690 5 <LOQ 45 0.4 78 100

USVI 001 <LOQ <LOQ <LOQ 0.3 70 90

African dust organic contaminants

• Garrison et al (2003)• Dioxins/furans detected in Mali samples

only (photolytic degradation during transport)

• Same suite of pesticides (8), PAHs (13), PCBs (9) in air samples from Mali and from dust events in USVI and Trinidad– much lower concentrations in USVI and

Trinidad

Redox-bioreactive PM?

• Freshly broken crystalline silica is redox-bioreactive; weathered silica much less so

• There is increasing attention to the role of ferrous iron and other variable-redox elements in formation of reactive oxygen species, oxidative stress, and toxicity

• Ferrous iron released from dissolving particles or particle surfaces?

24-hour in vitro asbestos dissolution tests in serum-based cell line fluids

0.5 g material in 20 ml fluid, leached at 37 °C for 24 hours, leachate filtered and analyzed

Iron in leachate

In vitro cell line toxicity

analysis 1B 2B 3B 4B 5B6B

7B 8B 9B 10B

11B

12B

13B

14B

15B

16B

17B

18B

19B

20B

21B

22B

23B

24B

25B

26B

27B

28B

29B

30B

6 m

ix (c

oars

e)6

mix

(fin

e)

0

50

100

Cel

l Via

bilit

y (%

of c

ontr

ol)

Libby Sample Number

Libby Amphibole

0

50

100

Cel

l Via

bilit

y (%

of c

ontr

ol)

Asbestos toxicological standardsShort-term toxicity does not seem to correlate with soluble iron

Ziegler et al., 2003

In vivo toxicity studies are needed to understand potential long-term toxicity

African dustsHigh Fe, Mn bioaccessibility in simulated lung fluids

Vµg/g bulk

V(µg

leached/g solid)

Mnµg/g bulk

Mn(µg

leached/g solid)

Feµg/g bulk

Fe (µg

leached/g solid)

Mali 627 105 2.3 723 129 40709 <50

Mali 623 108 4.0 679 117 40196 69

Mali 001 101 3.9 650 155 40628 100

Mali 005 101 2.6 702 136 40645 62

Mali 009 99 4.1 653 137 42099 111

Mali 016 106 4.3 741 134 45999 133

Mali 605 94 4.3 740 197 39361 303

Trinidad 629 69 <0.5 469 210 23865 1261Trinidad 634 75 <0.5 527 257 26508 1309

Trinidad 646 72 <0.5 503 294 25405 1453

USVI 690 74 17.2 397 115 22517 161

USVI 001 36 4.3 181 55 8937 <50

Summary• There are many different types of PM• Spectrum from natural (geogenic) to

anthropogenic• A broad spectrum of toxicologically relevant

characteristics• Earth science characterization methods can help

public health experts better understand the types, sources, and potential toxicity of PM and better evaluate the potential risks posed by PM from diverse sources (ie, the exposure and the dose)

African dusts• Are dominated by respirable particles• Contain biodurable but weathered crystalline

silica• Arsenic, cadmium and other heavy metals

are low in concentration but are highly bioaccessible

• Contain some organic contaminants• Iron and manganese are abundant and

bioaccessible – do they play a role in oxidative stress?

A growing role for earth scientists

• Helping understand the nature of PM to which human populations and ecosystems are being exposed