Environmental Engineering Reference
In-Depth Information
which. aggravated. the. acid. rain. problem. (due. to. sulfur),. in. addition. to. the.
emission.of.other.pollutants.such.as.Hg..(2).Solid.waste/land:.Huge.amounts.
of.wastes.have.been.generated,.without.eficient.waste.management,.result-
ing. in. severe. land. contamination. and. dereliction,. especially. those. caused.
by.mining.activities..(3).Water:.Only.16%.of.sewage.is.treated.in.Guangdong.
Province,.compared.with.other.provinces,.for.example,.62%.in.Shanghai.and.
42%.in.Jiangsu.(Ng.2003).
Moreover,. the. PRD. has. become. the. power. house. of. modern. appliances,.
producing.electrical.and.electronic. products,.textiles,. furniture,.shoes,. and.
so.on,.emitting.a.large.amount.of.POPs.and.emerging.chemicals.of.concern.
(such.as.lame.retardants,.bisphenol.A.[BPA])..There.is.also.an.urgent.need.to.
manage.the.illegal.import.of.e-waste.from.other.countries.as.well.as.the.ever-
rising. amount. of. e-waste. generated. domestically.. The. harmful. substances.
emitted. during. uncontrolled. recycling. of. e-waste. (notably. open. burning).
have.imposed.serious.adverse.effects.on.the.environment.and.the.health.of.
workers.and.residents.of.e-waste.recycling.sites,.which.is.evidenced.from.the.
rising. morbidity. of. major. diseases,. such. as. respiratory. and. cardiovascular.
diseases.and.malignant.tumors.(Wong.et.al..2007).
Soil Pollution Affecting Crops Grown in the Region
Because.of.the.favorable.weather,.fertile.soil,.and.abundant.water.resources,.
PRD.has.served.as.“homeland.for.crops.and.ish”.in.the.past..However,.the.
environmental. quality. of. our. region. has. deteriorated. due. to. recent. rapid.
socioeconomic. changes. indicated. earlier.. As. a. consequence,. domestic. and.
industrial.discharges.containing.nutrients,.heavy.metals,.pesticides,.PAHs,.
and.oil.are.prevalent.in.freshwater.and.coastal.marine.water.in.the.region..
These.led.to.eutrophication.and.formation.of.algal.bloom.and.red.tides,.deple-
tion.of.oxygen.and.contamination.of.water,.as.well.as.soil.erosion,.depletion.
of.soil.fertility,.and.contamination.of.soil.(Wong.and.Wong.2004).
Heavy.metals.are.released.from.different.industries,.for.example,.electro-
plating. factories. and. leather. tanneries,. but. mining. and. smelting. activities.
are.the.major.sources.of.these.toxic.metals.detected.in.farm.soils..In.addition,.
overuse.of.agrochemicals.and.phosphate.fertilizers.in.farm.soils.that.contain.
different.heavy.metals,.notably.Cd,.is.also.a.major.concern..Leachate.gener-
ated. from. waste. landills. also. contained. a. wide. range. of. toxic. chemicals,.
heavy.metals,.as.well.as.POPs.
Both.illegal.use.of.technical.DDTs.and.the.use.of.dicofol.containing.DDTs.
(as. impurities). are. also. a. major. fresh. input. of. DDTs. in. soils. (and. crops). in.
the.PRD.(Li.et.al..2006)..This.is.mainly.due.to.the.fact.that.China.had.pro-
duced. and. used. DDT. in. the. past,. resulting. in. high. background. levels. in.
soils..In.addition,.DDT.has.been.exempted.to.be.used.for.vector.control.in.
China.(although.agricultural.application.has.been.nonexistent.since.1983)..It.
is.also.expected.that.the.illegal.use.of.technical.DDTs.and.the.use.of.dicofol,.
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