Environmental Engineering Reference
In-Depth Information
Due. to. the. rapid. industrial. development. in. our. region,. Hg. emission.
from. coal. combustion,. metal. smelting,. and. relevant. industries. seems. to.
be.a.public.concern..There.is.a.severe.lack.of.information.concerning.the.
concentrations.and.speciation.of.Hg.in.different.ecological.compartments.
of. our. region. (Zhang. and. Wong. 2007).. Our. recent. study. demonstrated.
that. there. is. a. potential. danger. that. the. organic. matter. accumulated. in.
freshwater. ish. ponds.(around.the. Pearl.River.Delta. region). and.beneath.
mariculture.rafts.(along.the.coastal.areas.of.South.China).would.provide.
an.ideal.opportunity.for.sulfate.bacteria.to.transform.inorganic.mercury.
to. methyl. mercury. and. then. enter. cultured. ish. (Liang. et. al.. 2010,. Shao.
et.al..2011).
Stockholm Convention POPs
The. original. 12. POPs. included. 8. organochlorine. pesticides. (OCPs):. aldrin,.
chlordane,.DDT,.dieldrin,.endrin,.heptachlor,.mirex,.and.toxaphene;.2.indus-
trial. chemicals:. polychlorinated. biphenyls. (PCBs). and. hexachlorobenzene.
(which.is.also.a.pesticide);.and.2.combustion.by-products:.dioxins.and.furans.
(PCDDs. and. PCDFs).. Additional. POPs,. including. lame. retardants. (poly-
brominated. diphenyl. ethers. [PBDEs]),. have. been. added. to. the. list. recently..
Each. country. that. signed. the. legally. binding. treaty. is. required. to. develop.
a. National. Implementation. Plan. (NIP). to. fulill. the. obligations. under. the.
Stockholm.Convention.(Article.7),.either.to.eliminate.or.reduce.the.produc-
tion.and.usage.of.the.12.POPs.in.the.near.future..Each.country.also.needs.a.
strategy.to.fulill.monitoring.obligation..Regular.monitoring.of.these.chemi-
cals. in. different. ecological. compartments. (i.e.,. air,. soil/sediment,. water),.
biota,.and.human.tissues.is.required.
It.is.observed.that.levels.of.PCBs.and.dioxins/furans.in.all.environmen-
tal.media.were.relatively.low.in.China,.when.compared.with.other.indus-
trialized. countries. (Fiedler. et. al.. 2002,. Xing. et. al.. 2005).. Although. OCPs,.
including. eight. of. the. original. nine. pesticides. listed. in. the. Stockholm.
Convention.on.POPs,.and.PAHs,.detected.in.Hong.Kong.air.samples.were.
considered. to. be. at. a. low. level. and. that. they. would. not. pose. any. health.
hazards.(Choi.et.al..2008,.2009)..A.number.of.studies.indicated.the.gross.
contamination.of.DDTs.in.the.estuarine.system.in.South.China;.for.exam-
ple,.Iwata.et.al..(1993).tested.the.concentrations.of.DDT.in.the.suspended.
particulate. matter. in. surface. seawater. around. the. world. and. noted. the.
highest.concentration.of.DDT.in.the.South.China.Sea,.which.is.very.near.
to.Hong.Kong.and.Macao.
Our.early.studies.indicated.that.the.inland.river.systems.and.ish.ponds.
in.the.Pearl.River.Delta.were.grossly.polluted.by.PCBs,.HCHs,.and.DDTs,.
which.resulted.in.higher.concentrations.of.these.chemicals.in.ish.collected.
from.inland.rivers.as.well.as.ish.ponds.(Liang.et.al..1999,.Zhou.et.al..1999a,.
Zhou. and. Wong. 2000).. The. uptake. of. these. chemicals. seemed. to. depend.
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