Environmental Engineering Reference
In-Depth Information
22
Bioavailability of Metals and Arsenic on
Brownield Land: Remediation or Natural
Attenuation
for Risk Minimization?
NicholasM.Dickinson,WilliamHartley,AmandaBlack,
andCameronS.Crook
CONTENTS
Introduction.......................................................................................................... 473
Bioavailability....................................................................................................... 474
Case.Study............................................................................................................ 477
Habitat.Creation.on.Brownield.Land.............................................................. 481
Conclusions.......................................................................................................... 481
References............................................................................................................. 482
Introduction
Soil. concentrations. of. metals. and. arsenic. (As). elevated. above. background.
levels.have.raised.considerable.concern.in.restoration.projects,.particularly.in.
the.context.of.potential.risks.to.human.health..Certainly,.there.is.no.shortage.
of. available. regulatory. documentation. and. guidance.. Routes. of. transfer. of.
pollutants.from.soil.to.receptor.are.the.most.critical.part.of.risk.assessment,.
but.the.extent.to.which.bioavailability.of.metals.and.As.is.considered.is.vari-
able.. When. taken. into. account,. predictors. and. assays. of. lability,. mobility,.
and.bioavailability.are.well.known.to.be.of.restricted.eficacy.in.predicting.
uptake. and. impact. on. biota,. largely. due. to. differing. soil. types. and. envi-
ronmental. conditions.. This. means. that. broad.generalizations. and. accurate.
interpretation.of.the.risks.posed.by.elevated.and.potentially.toxic.soil.trace.
elements. in. soils. are. dificult,. requiring. consideration. on. the. basis. of. each.
particular. trace. element,. site,. and. environmental. conditions.. It. also. raises.
concern. because. expensive. and. inappropriate. risk-based. decisions. may. be.
taken.to.remove.potential.risk,.for.example,.involving.extensive.but.unnec-
essary.site.engineering..Indeed,.justiication.and.securement.of.funding.for.
473
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