Environmental Engineering Reference
In-Depth Information
O
FIGURE 7.1
Molecular.structure.of.PBDEs.m.=.1-5,.n.=.0-5.
Br
m
Br
n
In.the.case.of.ire,.PBDEs.release.bromine.atoms,.which.are.strong.reduc-
ing.agents.for.capturing.burning.ions.such.as.-OH.and.=O.at.high.tempera-
tures..This.causes.a.release.of.high-density.unburning.gases.that.separate.air.
away.from.the.burning.center,.thereby.retarding.the.ire.
The. molecular. formula. of. PBDEs. is. C
12
H
(0-9)
Br
(1-10)
,. and. the. structure. is.
shown.in.Figure.7.1..It.is.composed.of.two.rings.(phenyl.rings).linked.by.an.
oxygen.bridge.(ether.linkage)..“Polybromine”.means.many.“bromine”.atoms.
linked.to.carbons.on.the.phenyl.rings..There.are.up.to.10.locations.where.the.
bromine.atom.can.attach.to.the.carbons.on.the.rings;.for.example,.if.a.PBDE.
has.10.bromines,.it.is.called.a.deca-BDE;.if.it.has.5.bromines,.it.is.called.penta-
BDE..As.a.result,.there.are.209.possible.congeners.of.PBDEs,.all.of.which,.like.
polychlorinated.biphenyls.(PCBs),.are.numbered.by.the.International.Union.
of.Pure.and.Applied.Chemistry.(IUPAC).
PBDE.products.have.been.widely.used.for.global.commercial.requirements.
and.are.produced.with.three.degrees.of.bromination:.penta-,.octa-,.and.deca-
BDE. technical. mixture. (La. Guardia. et. al.. 2006).. Penta-BDEs. are. added. to.
foam.mainly.for.manufacturing.furniture,.car.cabins,.and.chairs..Octa-BDEs.
are.mainly.used.in.textiles.and.plastic.products.such.as.the.outer.covering.
for.TVs,.computers,.and.DVDs..Deca-BDEs.consist.of.80%.of.the.total.PBDE.
production.and.are.primarily.used.in.electronic.products.(La.Guardia.et.al..
2006).. The. amount. of. brominated. lame. retardants. produced. was. around.
239,000.t.per.annum.during.the.twentieth.century,.with.nearly.30%.consist-
ing.of.PBDEs..The.estimated.world.market.demand.was.67,125.t.in.1999.(Liu.
et.al..2005b).
PBDEs.possess.physiochemical.properties.similar.to.that.of.PCBs,.which.are.
chlorinated.congeners.with.teratogenic,.mutagenic,.and.carcinogenic.proper-
ties..The.fate.and.behavior.of.PBDEs.and.PCBs.are.comparable..PBDEs.have.
been.associated.with.endocrine.disruption,.reproductive-developmental.tox-
icity,.including.neurotoxicity.and.even.carcinogenicity..The.toxicological.end.
points.of.concern.for.environmental.levels.of.PBDEs.are.likely.to.be.thyroid.
hormone. disruption,. neurodevelopmental. deicits,. and. cancer. (Manchester.
et.al..2001,.McDonald.2002).
Prior.to.2004,.there.was.a.paucity.of.published.articles.(both.in.Chinese.and.
English).about.PBDE.contamination.in.mainland.China..There.were.only.a.
few. articles. written. in. English,. concerning. Hong. Kong. and. Taiwan.. Since.
2007,.the.number.of.articles.on.PBDEs.(in.both.languages).related.to.main-
land.China.has.steadily.increased..This.review.summarizes.the.sources,.lev-
els,. trends,. and. adverse. impacts. of. PBDEs. on. human. health. in. mainland.
China,. Hong. Kong,. Taiwan,. and. Macau.. Comparisons. are. made. between.
data.generated.in.China.with.those.from.other.parts.of.the.world.
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