Environmental Engineering Reference
In-Depth Information
would. allow. human. ingestion. of. metals.. Another. site,. a. former. chemical.
waste. dump. adjacent. to. a. residential. area. in. St.. Helens,. United. Kingdom,.
had. been. converted. to. a. recreational. park. land,. and. was. found. to. contain.
elevated.arsenic.(As).in.surface.soil.at.concentrations.200.times.higher.than.
soil-guideline.values..Despite.this,.the.existing.vegetation.cover.was.appar-
ently.healthy.and.was.likely.to.minimize.re-entrainment.of.dust-blown.par-
ticulates.that.presented.the.only.potential.risk.to.human.health..In.this.case,.
the. results. of. extensive. detailed. study. suggested. it. was. advisable. to. avoid.
disturbance.and.exposure.of.soil.surface,.and.compost.and.phosphate.appli-
cation. that. may. result. in. the. solubilization. or. mobilization. of. As. (Figures.
22.2.and.22.3)..Otherwise,.in.terms.of.management.of.the.site,.the.effective-
ness.of.monitored.natural.attenuation.and.the.feasibility.of.reliance.on.phy-
tostabilization. for. long-term. management. were. demonstrated. to. be. quite.
adequate.
A.number.of.other.studies.have.similarly.demonstrated.the.importance.of.
understanding. the. signiicance. of. bioavailability. in. the. context. of. sustain-
able. rehabilitation. of. metal-contaminated. brownield. land.. This. is. initially.
relected. in. the. effectiveness. of. natural. vegetation. processes. in. withstand-
ing. and. ameliorating. potential. toxicity.. Rawlinson. et. al.. (2004). found. that.
metal.contamination.did.not.limit.vegetation.establishment.in.ield.trials.at.a.
100%
80%
60%
40%
20%
0%
Untreated
GWC
Soil treatment
Water
Sodium bicarbonate (0.5 M)
Hydrochloric acid (1 M)
Sodium hydroxide (0.1 M)
Nitric acid (14 M)
FIGURE 22.2
Arsenic.fractionation.in.an.industrially.contaminated.soil.amended.with.green.waste.compost.
(30%.v/v),.using.the.method.of.Shiowatana.et.al..(2001)..(From.Hartley,.W..et.al.,.
Environ. Pollut
.,.
157,.847,.2009.)
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