Environmental Engineering Reference
In-Depth Information
17
Toxicity and Bioavailability of Heavy
Metals and Hydrocarbons in Mangrove
Wetlands a
nd Their Remediation
LinKeandNoraF.Y.Tam
CONTENTS
Introduction.......................................................................................................... 371
Plant.Response.to.Toxicity.................................................................................. 373
Root.Anatomy.and.Radial.Oxygen.Loss..................................................... 373
Fe.Plaque.Formation....................................................................................... 376
Biochemical.Response.................................................................................... 379
Bioavailability.and.Remediation....................................................................... 381
Heavy.Metals................................................................................................... 381
Hydrocarbons.................................................................................................. 382
Concluding.Remarks........................................................................................... 384
Acknowledgment................................................................................................ 385
References............................................................................................................. 385
Introduction
Mangrove.wetlands.are.coastal.wetland.ecosystems.that.dominate.the.inter-
tidal. zone. of. tropical. and. subtropical. foreshore. areas.. The. ecological,. envi-
ronmental,. and. socioeconomic. importance. of. mangrove. wetlands. has. been.
widely.recognized..They.have.an.extraordinarily.high.rate.of.primary.produc-
tivity.(Alongi.2002),.act.as.both.an.atmospheric.CO
2
.sink.and.as.an.essential.
source.of.oceanic.carbon.(Cahoon.et.al..2003,.Chmura.et.al..2003),.provide.nurs-
ery.grounds.and.refuge.for.ecologically.and.commercially.important.marine.
organisms. (Primavera. 1998,. Mumby. et. al..2004),. protect. coastal.erosion.and.
maintain.shore.stability.(Dahdouh-Guebas.et.al..2005,.Danielsen.et.al..2005),.
and. ilter. river-borne. sediment. and. nutrients. to. minimize. their. inputs. into.
more. sensitive. systems,. such. as. seagrass. beds. and. coral. reefs. (Alongi. and.
McKinnon.2005)..Mangrove.wetlands.are.under.a.serious.threat.of.anthropo-
genic.pollution.due.to.the.current.population.expansion.and.accompanying.
371
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