Pragmatic Approach for Health Risk Assessment of Bauxite Tailing Waste Materials - Environmental Contamination: Health Risks and Ecological Restoration - page 106

(e.g.,.in. the. form.of.vanadium. pentoxide).. Although. the. form.of.vanadium.
in.the.bauxite.dust.has.not.been.determined,.it.is.reasonable.to.believe.that.
at.least.some.of.it.will.be.present.in.relatively.insoluble.forms,.such.as.sul-
ide. and. other. mineral-bound. species.. This. is. relected. in. a. relatively. low.
bioaccessibility.of.less.than.5%.
Other Metal/Metalloids
Concentrations.of.other.metals/metalloids.tested.(see.Table.6.5).are.relatively.
low.and.below.the.recommended.NEPM.HIL.values,.which.warrants.further.
detailed. risk. assessment. (NEPC. 1999).. It. is. worth. noting. that. certain. indi-
viduals.could.be.allergic.to.nickel.metal.(ATSDR.1997)..However,.the.risk.of.
this.occurring.is.considered.low.because.of.the.relatively.low.concentration.
of.nickel.found.in.the.samples.
Particulate Matter with Special Reference to Crystalline Silica (Quartz)
Particulate.matter.levels.in.relation.to.their.effects.on.human.health.are.com-
monly. expressed. on. the. basis. of. mass. concentration. of. inhalable. particles,.
which. is. deined. as. containing. particles. with. an. aerodynamic. diameter.
equal. to. or. less. than. 10.μm.. This. is. because. only. these. small. particles. can.
penetrate.into.the.airways.and.lungs.
In. Australia,. the. NEPM. air-quality. standards. for. particulate. concen-
trations. are. similar. to. those. recommended. by. WHO.. The. current. 1. day.
average. for. particles. up. to. PM 10 . is. 50.μg/m 3 ,. with. a. maximum. allowable.
exceedance. of. 5. days. a. year,. and. for. particles. up. to. PM 2.5 ,. it. is. 25.μg/m 3 .
for. 1. day. (NEPC. 1999).. In. the. United. States,. the. PM 10 . standard. is. set. at.
150.μg/m 3 . at. 24.h. average. and. 50.μg/m 3 . at. 1. year. average.. The. respective.
values.for.PM 2.5 .are.15.and.65.μg/m 3 .and.these.values.will.become.effective.
from.2012.(USEPA.2004)..As.one.can.see,.setting.health.standards.is.com-
plicated..However,.it.is.understood.that.standards.have.to.be.conservative.
but.not.overly.so.
Inhalation. of. particulate. matter. can. exacerbate. existing. pulmonary. and.
cardiac. vascular. diseases,. oxidative. stress,. and. inlammation. (CARB. 2002,.
CEPA. 1998,. IAEA.2008,. Pope. and.Dockery.2006,. WHO. 2007).. For.example,.
Ghio.et.al..(2000).measured.exposure.to.concentrated.ambient.PM2.5.levels.
in. the. range. of. 23-311.μg/m 3 .. Exposures. for. a. period. of. 2.h. were. found. to.
induce.transient,.mild.pulmonary.inlammatory.reactions.in.healthy.human.
volunteers.exposed.to.the.highest.concentrations.(average.of.200.μg/m 3 )..The.
PM 10 . at. the. residential. area. was. found. to. peak. at. 149.μg/m 3 . once. with. an.
average. of. 48.5.μg/m 3 . (detailed. data. not. shown). during. a. survey. period. of.
3. months. when. earthmoving.activities. were.at.the. highest. scale.. This.sug-
gests.that.exposure.to.dust. per se .would.present.a.relatively.low.health.risk.to.
healthy.individuals..However,.discomfort.might.have.been.experienced.by.
asthmatics.and.patients.with.compromised.pulmonary.or.cardiac.functions,.