5 research outputs found
Acrylamide monomer leaching from polyacrylamide-treated irrigation furrows
Water-soluble anionic polyacrylamide (WSPAM), which
is used to reduce erosion in furrow irrigated fields and other
agriculture applications, contains less than 0.05% acrylamide
monomer (AMD). Acrylamide monomer, a potent neurotoxicant
and suspected carcinogen, is readily dissolved and transported in
flowing water. The study quantified AMD leaching losses from
a WSPAM-treated corn (Zea mays L.) field using continuous
extraction-walled percolation samplers buried at 1.2 m depth.
The samplers were placed 30 and 150 m from the inflow source
along a 180-m-long corn field. The field was furrow irrigated
using WSPAM at the rate of 10 mg L?1 during furrow advance.
Percolation water and furrow inflows were monitored for AMD
during and after three furrow irrigations. The samples were
analyzed for AMD using a gas chromatograph equipped with an
electron-capture detector. Furrow inflows contained an average
AMD concentration of 5.5 ?g L?1. The AMD in percolation
water samples never exceeded the minimum detection limit and
the de facto potable water standard of 0.5 ?g L?1. The risk that
ground water beneath these WSPAM-treated furrow irrigated
soils will be contaminated with AMD appears minimal
Fate of acrylamide monomer following application of polyacrylamide to cropland
Acrylamide (AMD) is the basic
monomeric unit used in the production
of a major class of water soluble
polymers, generically termed polyacrylamides
(PAMs). The structural
formula of AMD is shown in Fig. 1.
Under the proper conditions and with
suitable catalysts, AMD can polymerize
with other molecules of AMD, or
with other vinyl monomers to yield
products with extremely high molecular
weights. PAMs with molecular
weights in excess of 10 million,
i.e. with chain lengths of more than
105,000 monomeric units, are produced
commercially. By utilizing the
appropriate comonomers or by postreaction
with other reagents, these
polymers may be cationic, nonionic.
or in the case of those used to control
soil erosion, anionic. The anionic reaction
product of AMD and a salt of
acrylic acid is shown in Fig. 2. The
same chemical structure can also be
produced by hydrolysis of the nonionic
homopolymer of AMD or by
hydrolysis of polyacrylonitrile
Irrigating with polyacrylamide (PAM) - Nine years and a million acres of experience
Polyacrylamide (PAM) has been available commercially since 1995 for reducing
irrigation-induced erosion and enhancing infiltration. The first series of practical field tests was
conducted in 1991. PAM used for erosion control is a large water soluble (non-crosslinked)
anionic molecule (12-15 megagrams per mole) containing < 0.05% acrylamide monomer. In
controlled field studies PAM eliminated, on average, 94% (80-99% range) of sediment loss in field
runoff from furrow irrigation, with a typical 15-50% relative infiltration increase on medium to fine
textured soils compared to untreated controls. Similar but less dramatic results have been seen with
sprinkler irrigation. Under some conditions infiltration is unchanged or can even be slightly
reduced, e.g. in sandy soils or where PAM application rates are very high. Results are achieved
with per irrigation field application rates of about 1 kg per hectare, for furrow irrigation, and 2 to 4
kg per hectare for sprinkler irrigation. Cost of PAM is 13 per kg. Seasonal application
totals vary from 3 to 7 kg per hectare. Farmer field sediment control has been around 80% of test
plot results. Substantial runoff reductions have been documented for nutrients, pesticides,
microorganisms, BOD, and weed seed. No adverse effects have been seen for soil microbial
populations. Crop yields have not been widely documented, though evidence exists for yield
increases related to infiltration improvement. High effectiveness, low cost, and ease of application,
compared to traditional conservation measures, has resulted in rapid technology acceptance in the
US and internationally. PAM-use for runoff water quality protection is one of the most potent
new irrigation environmental technologies in the market place. New uses in construction and
dryland erosion control are being developed rapidly. This paper discusses new insights and
understanding of PAM-use and potential for future development
Fate of acrylamide monomer following application of polyacrylamide to cropland
Acrylamide (AMD) is the basic
monomeric unit used in the production
of a major class of water soluble
polymers, generically termed polyacrylamides
(PAMs). The structural
formula of AMD is shown in Fig. 1.
Under the proper conditions and with
suitable catalysts, AMD can polymerize
with other molecules of AMD, or
with other vinyl monomers to yield
products with extremely high molecular
weights. PAMs with molecular
weights in excess of 10 million,
i.e. with chain lengths of more than
105,000 monomeric units, are produced
commercially. By utilizing the
appropriate comonomers or by postreaction
with other reagents, these
polymers may be cationic, nonionic.
or in the case of those used to control
soil erosion, anionic. The anionic reaction
product of AMD and a salt of
acrylic acid is shown in Fig. 2. The
same chemical structure can also be
produced by hydrolysis of the nonionic
homopolymer of AMD or by
hydrolysis of polyacrylonitrile