Microbial Transformation of Phthalate Esters: Diversity of Hydrolytic Esterases - Environmental Contamination: Health Risks and Ecological Restoration - page 318

inding.supported.by.the.fact.that.DEHP.is.the.most.commonly.used.phthal-
ate.ester.(Jeng.1986).
When.the.PAEs.enter.rivers.or.streams,.some.are.resistant.to.decomposi-
tion.and.may.be.transported.for.long.distance.into.the.sea..Therefore,.it.is.not.
surprising.to.detect.PAEs.occurring.in.the.marine.environment.(Jeng.1986,.
Chen.et.al..1999,.Cincinelli.et.al..2001,.Wenger.and.Isaksen.2002,.Mackintosh.
et. al.. 2004,. Zhao. et. al.. 2004a).. Recent. studies. showed. that. the. distribution.
pattern. of. organic. chemicals. is. inluenced. not. only. by. their. physiochemi-
cal. attributes. but. also. by. the. receiving. water. layer. structure.. A. level. of.
177.μg/L. phthalate. was. detected. in. the. marine. environment,. especially. in.
the. sea. surface. microlayer. that. contained. a. higher. concentration. than. the.
subsurface. water. (Cincinelli. et. al.. 2001).. According. to. the. report,. the. rea-
son.for.the.concentration.at.sea.surface.microlayer.was.probably.due.to.the.
natural. hydrophobic. property. or. the. absorption. of. loatable. particles.. Sea.
surface.microlayer.is.deined.as.1000.μm.of.the.ocean.surface.(Liss.1997)..As.
the.interface.of.gas.and.liquid,.sea.surface.microlayer.is.very.important.for.
marine.ecosystem,.because.of.its.abundant.assemblage.of.microorganisms,.
such.as.bacteria.(Sieburth.1971)..A.noticeable.consequence.of.PAEs.existence.
in.surface.microlayer.would.result.in.the.exposure.of.these.microorganisms.
to.PAEs.
On. the. other. hand,. the. water. conditions,. such. as. salinity,. also. affect.
the. distribution. of. organic. chemicals.. In. some. speciic. areas,. like. in. the.
junction. between. freshwater. and. sea. water. such. as. estuaries,. which. was.
affected.differently.by.salinity,.phthalate.esters.were.found.to.behave.much.
differently.. Turner. and. Rawling. (2000). gave. a. detailed. discussion. on. the.
distribution.of.DEHP.and.the.factors.affecting.both.freshwater.and.saltwa-
ter.. The. results. suggested. that. the. distribution. was. largely. inluenced. by.
the.particulates.and.salinity.in.water..Generally.speaking,.the.particulate.
organic.matters.can.partly.dissolve.DEHP.in.both.waters..However,.salinity.
may.increase.the.solvency.of.particulate.organic.matters.by.salting.out.or.
structure.modiication;.as.a.result,.the.concentration.of.DEHP.in.sea.water.
was. lowered. (Turner. and. Rawling. 2000).. The. particle. concentration. also.
had.a.relationship.to.the.distribution.coeficient.( K D ),.but.the.particle.con-
centration. in. sea. water. had. less. effect. on. the. K D . than. that. in. fresh. water,.
which. was. probably. caused. by. the. particle-particle. interaction. that. was.
weakened. in. high. salinity. (Fatoki. and. Ogunfowokan. 1993,. Heindel. et. al..
1995,. Paune. et. al.. 1998,. Turner. and. Rawling. 2000,. Luks-Betlej. et. al.. 2001,.
Mihovec-Grdic. et. al.. 2002,. Cai. et. al.. 2003,. Fauser. et. al.. 2003,. Gomes. and.
Lester.2003,.Gomes.et.al..2003,.Salafranca.et.al..2003,.Mackintosh.et.al..2004,.
Zhao.et.al..2004a,.Zhu.et.al..2004).
Sediments and Soils
The.PAEs.occurring.in.the.sediments.or.soils.probably.originated.from.the.
corresponding. water. sources,. such. as. the. discharge. of. rivers,. streams,. or.