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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: Michelle Wayment
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

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