Environmental Contamination: Health Risks and Ecological Restoration - Environmental Contamination: Health Risks and Ecological Restoration - page 12

soils/waters.contaminated.by.heavy.metals,.(1).heavy.metal.tolerance.plants.
(which.avoid.taking.up.toxic.metals.into.their.tissues).are.used.to.stabilize.
(phytostabilization). the.contaminated.sites. containing.high.levels. of. heavy.
metals.such.as.Pb.and.Zn;.(2).heavy.metal.hyperaccumulating.plants.(which.
are.able.to.absorb.and.translocate.toxic.metals.from.roots.into.their.upper-
ground.tissues).are.used.to.remove.(phytoextraction).a.substantial.amount.
of.toxic.metals.from.the.sites,.upon.harvest;.and.(3).wetland.plants.(such.as.
Typha .sp..and. Phragmites .sp.).are.used.to.remove.toxic.metals.from.wastewa-
ters.by.precipitating.toxic.metals.in.the.rhizosphere.soils.(Wong.2003).
In.terms.of.treating.sites.contaminated.by.organic.contaminants.(such.as.
DDT. and. PAHs),. methods. used. in. phytoremediation. include. (1). phytodeg-
radation,. which. relies. on. the. internal. and. external. metabolic. processes. of.
plants.to.break.down.organic.contaminants;.(2).rhizodegradation.is.the.use.
of.microbes.associated.with.rhizosphere.soils.to.degrade.soil.contaminants,.
and.the.process.could.be.enhanced.by.certain.plants.that.activate.microbial.
activity;.and.(3).phytovolatilization.refers.to.the.uptake.of.organic.contami-
nants.that.are.soluble.in.water.and.their.subsequent.release.into.the.atmo-
sphere.through.transpiration.by.plants.(Alkorta.and.Garbisu.2001).
IssuesAddressedin This Topic
Health Impacts and Risk Assessment
In. Part. I,. “Health. Impacts. and. Risk. Assessment,”. there. are. ive. chapters.
that. further. illustrate. different. timely. topics. in. depth.. Chapter. 2. is. aimed.
at.reviewing.the.current.environmental.problems.in.the.PRD.region,.which.
may. link. with. health. impacts. encountered. in. Hong. Kong,. and. calling. for.
health. care. reform. in. the. region. by. adopting. more. effective. management,.
based.on.dietary.modiication,.nutrition.supplementation,.and.detoxiication.
of.contaminants.accumulated.in.our.bodies..The.investigation.presented.in.
Chapter. 3. is. based. on. the. data. concerning. autistic. children. collected. from.
Mainland. and. Hong. Kong,. demonstrating. the. close. association. between.
environmental. heavy. metal. poisoning. and. the. development. of. autism..
Unfortunately,.there.seems.to.be.a.continuous.rise.on.the.number.of.cases.dis-
closed.in.South.China..The.risk.and.potential.effects.of.endocrine-disruptive.
contaminants. to. the. reproductive. and. developmental. health. are. reviewed.
in.Chapter.4..Some.of.these.POPs.(such.as.DDTs,.PBDEs,.and.PFOA/PFOS).
share.similar.structure.and.behavior.with.our.hormones.and,.therefore,.can.
adversely.affect.our.normal.physiology.and.development..Chapter.5.assesses.
health.risks.from.arsenic.(As).intake.by.residents.in.Cambodia,.by.analyzing.
As.concentrations.in.the.underground.water,.which.has.been.used.as.drink-
ing.water.by.local.residents,.and.in.the.hair.samples.of.local.residents.with.
the.prevalence.of.arsenicosis..Chapter.6.is.an.excellent.example.to.indicate.