Biomethylation of Arsenic in Contaminated Soils - Environmental Contamination: Health Risks and Ecological Restoration - page 247

other. fungal. species. but. at. this. time. the. exact. chemical. nature. of. these.
poisonous.arsenical.were.not.known.(Agrifoglio.1954).
With.the.advent.of.improved.chemical.methods.for.detecting.methylated.
forms. of. As,. Fredrick. Challenger. in. the. 1940s. was. the. irst. to. link. fungal.
species.to.a.speciic.arsenical.gas,.TMA..He.and.coworkers.at.the.University.
of.Leeds.found.low.levels.of.TMA.emitting.from.pure.cultures.of. Aspergillus
glaucus . or. A. versicolor .. They. further. showed. that. these. organisms. and.
Penicillium notatum ,. P. chrysogenum ,.and.two.strains.of. Aspergillus niger .could.
convert. DMA. to. TMA. (Bird. et. al.. 1948).. A. number. of. fungal. species. were.
grown. on. As 2 O. and. were. indirectly. associated. with. As. volatilization. by.
producing.garlic-like.odors.which.included. Lenzites trabea ,. Lenzites saepiaria ,.
Phaaeolus schweinizii ,.and. Tricohphyton rubrum .when.grown.in.the.presence.of.
As.(Zussman.et.al..1975,.Barret.1978,.Pearce.et.al..1998).
Other.fungi.species,.associated.with.As.biomethylation,.have.been.isolated.
from. various. environmental. samples.. With. the. widespread. use. of. CCA. as.
wood.preservative. since.the.1970s.until.recently,.there. has.been.interest.in.
degradation. of. treated. wood. and. release. of. As.. Cullen. et. al.. (1984). found.
that. C. humiculus .growing.on.preserved.wood.could.release.TMA..DMA.was.
converted.to.TMA.by.three.fungi.isolated.from.sewage.sludge.( Gliocladium
roseum ,. Penicillium .sp.,.and. Candida humicola ,.later.reclassiied.as. Apiotrichum
humicola .by.Cullen.et.al..(1995).(Cox.and.Alexander.1973).
Frankenberger.and.coworkers.have.done.in-depth.studies.of.a. Penicillium .
species.isolated.from.an.agricultural.evaporation.pond..Environmental.con-
ditions.that.promoted.TMA.release.by.this.organism.are.discussed.in.detail.
later.in.this.chapter.
A. species. of. Fusarium . was. isolated. from. soil. contaminated. with. a. cattle.
medicinal.solution.dip.(As.trioxide).more.than.30.years.after.the.contamina-
tion.(Thomas.and.Rhue.1997)..In.pure.culture.this.organism.released.arseni-
cals.of.unknown.chemical.structure.
Cernansky.et.al..(2009).investigated.the.potential.of.three.microscopic.ila-
mentous.fungi.strains.isolated.from.soil.samples.collected.from.a.mining.site.
highly.contaminated.with.As..In.pure.culture.the.fungi.released.arsenicals.
from.As.(III).or.As.(V).in.the.following.order:. Neosartorya ischeri > Aspergillus
clavatus > A. niger .which.averaged.across.all.fungi.was.24%.and.16%.for.As.
(V). addition. of. 4.and.17.mg/L,.respectively. (similar.results. were.found.for.
As.III)..Interestingly,.even.though.As.(III).is.considered.to.be.more.toxic.than.
As.(V),.there.were.minimal.differences.in.fungal.biomass.or.As.volatiliza-
tion..A.more.important.factor.was.As.concentration.which.on.a.percentage.
basis.was.higher.at.the.lower.concentration..However,.this.stands.in.contrast.
to.Pearce.et.al..(1998).who.found.no.effect.of.initial.As.concentration.on.As.
volatilization.by.fungi.
Table.12.3.presents.fungi.identiied.by.Cernansky.et.al..(2007).that.could.
volatilize.As..An.important.inding.of.this.research.was.that.the.amount.of.
As. volatilized. was. higher. for. the. A. niger . strains. isolated. from. the. uncon-
taminated. than. those. from. a. contaminated. soil.. This. may. be. due. to. the.