Estimating polyacrylamide concentration in irrigation water

Lentz, R.D. and Sojka, R.E. and Foerster, J.A. (1996) Estimating polyacrylamide concentration in irrigation water. Journal of Environment Quality. 25:1015-1024.

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Abstract

One practice used to control irrigation-induced erosion amends
irrigation furrow inflows with water-soluble, anionic polyacrylamide
(PAM) at low concentrations (0.25-10 mg L-1). Researchers wish to
determine the fate of PAM, once added to furrow water streams. We
developed and tested an instrumented flocculation test for quantifying
PAM concentration in irrigation water. A kaolinite mineral standard
is mixed with a PAM-amended water sample, agitated, then placed
in a spectrophotometer. The PAM concentration in the suspension
was correlated with settling-related transmittance changes. One highly
correlated (r 0.91-0.98) parameter, the time needed to initiate
suspension clearing (clarity-shift inflection, CS1), was used as the
procedure endpoint. The procedure was sensitive to variations in the
amount of kaolinite added, and sample volume, water salinity, and
original sediment content. A 10% change in these factors altered
measured CSIs by 10 to 50%. The sediment affected CSI by increasing
the sample's dissolved organic C concentration. The procedure detected
as little as 0.1 mg PAM dissolved in irrigation water; in samples
containing >4 mt. settled sediment per liter, the PAM detection limit
was approximately 0.25 mg L-`. Precision ranged from ±0.06 to 0.11
mg L-1 for 0 to 2.5 mg L-1 PAM and ±0.39 to 0.86 mg L-1 for 2.5
to 10.0 mg L-1 PAM. The PAM concentration in runoff from irrigated
furrows equaled that of the inflow stream after 3 b continuous treatment
at 10 mg L-1. The CSI test provides a simple and accurate
method of determining polyacrylamide in surface waters.

Item Type:	Article
NWISRL Publication Number:	0917
Subjects:	Polyacrylamide (PAM) > Water-soluble PAM (WSPAM) Research methodology Mass Import - autoclassified (may be erroneous)
Depositing User:	Users 6 not found.
Date Deposited:	20 Nov 2010 21:54
Last Modified:	22 Nov 2016 22:45
Item ID:	666
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/666