Environmental Engineering Reference
In-Depth Information
table .
Case study using the nano Risk Framework: nano zero-Valent iron []
Framework step
analysis
1...Describe.Material.and.
Application
Nano.zero-valent.iron.in.nano-sized.particles.(nZVI).serves.as.a.reagent.to.
dechlorinate.compounds.such.as.tetrachloroethylene.in.groundwater..
Vendors.ship.a.highly.concentrated.slurry.of.nZVI.to.a.contaminated.
site,.where.it.is.mixed.with.water.and.injected.into.an.aquifer.via.small-
diameter.wells..DuPont.did.not.produce.or.use.nZVI.at.the.time.of.the.
case.study.
2..Proile.Lifecycle(s)
nZVI.slurries.contain.iron.particles.manufactured.by.one.of.several.
processes..The.properties.of.the.iron.particles.vary,.depending.on.the.
manufacturer..Additives.used.to.stabilize.the.nZVI.slurries.also.vary.
with.the.manufacturer..Information.on.both.the.nZVI.particles.and.the.
stabilizers.is.proprietary..Environmental.health.and.safety.data.from.
suppliers.varied.in.quality.and.completeness,.and.may.have.represented.
larger-sized.“simple.iron.powder”.rather.than.nZVI..Toxicological.
properties.have.not.been.thoroughly.investigated..Warnings.included.the.
potential.for.skin.or.eye.irritation.upon.contact,.irritation.of.mucous.
membranes.and.upper.respiratory.tract.if.inhaled,.and.may.have.a.
laxative.effect.if.swallowed.
Effective.use.of.nZVI.to.treat.chlorinated.compounds.in.groundwater.
requires.adequate.contact.between.nZVI.and.the.contaminants;.
incomplete.destruction.could.generate.toxic.partial.degradation.
products..Spent.iron.typically.precipitates.as.carbonate.or.sulide.
minerals.
3..Evaluate.Risks
The.case.study.did.not.include.a.risk.assessment.due.to.the.stage.of.the.
technology.and.DuPont's.decision.not.to.apply.the.technology.
4...Assess.Risk.
Management
The.case.study.did.not.evaluate.risk.mitigation.measures.due.to.the.
stage.of.the.technology.and.DuPont's.decision.not.to.apply.the.
technology.
5...Decide,.Document,.
and.Act
“DuPont.would.not.consider.using.this.technology.at.a.DuPont.site.until.
the.end.products.of.the.reactions.following.injection,.or.following.a.
spill,.are.determined.and.adequately.assessed.”.The.case.study.identiied.
ive.speciic.questions.that.must.be.addressed.
6..Review.and.Adapt
“DuPont.will.monitor.the.status.of.this.technology.to.review.and.update.
the.decision.as.additional.information.becomes.available.”
Summary.of.Outcome
Based.on.information.available.as.of.March.2007,.DuPont.has.no.
immediate.plans.to.implement.this.technology.at.any.DuPont.site.
 
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