TY - JOUR
T1 - Impact of polyacrylamide treatment on sorptive dynamics and degradation of 2,4-D and atrazine in agricultural soil
AU - Watwood, Mary E.
AU - Kay-Shoemake, Jeanine L.
N1 - Funding Information:
This work was supported by an NRICGP Strengthening Award from the USDA and by the NSF-Idaho EPSCoR Program - National Science Foundation Cooperative Agreement OSR-935039. The authors are grateful to the USDA Agricultural Research Service's Northwest Irrigation and Soils Research Laboratory at Kimberly, Idaho for access to experimental fields. We especially thank Drs. Robert Sojka and Rick Lentz for valuable discussions and assistance.
PY - 2000
Y1 - 2000
N2 - High-molecular-weight, anionic polyacrylamide (PAM) is added to irrigation water to reduce soil erosion during furrow irrigation of crops. The chemical nature of PAM, together with the observation that the polymer can be biotransformed by soil bacteria, led us to question the impact of PAM treatment on the fate of coapplied agrochemicals. The herbicides, atrazine (nonionic) and 2,4-D (anionic), were tested for pesticide sorption, desorption, and degradation in PAM-treated and untreated soils. Sorption of atrazine and 2,4-D in soil was unaffected by PAMtreatment, as was atrazine desorption. However, 2,4-D desorbed more readily from the PAM-treated soil than from untreated soil. With respect to pesticide degradation, mineralization of the 2,4-D aromatic ring was not impacted by PAM treatment, but decarboxylation of the 2,4-D carboxylic acid side chain was significantly reduced in the PAM-treated soil. Limited mineralization (7 to 10%) of atrazine was observed in both soils. However, in PAMtreated soils atrazine conversion to 14CO2 and bound residue components was significantly reduced, and there was an increase in the level of methanol extractable metabolites. These results may indicate that PAM application can alter the environmental fate of some pesticides in soils, especially under the high dose treatment conditions examined in this study.
AB - High-molecular-weight, anionic polyacrylamide (PAM) is added to irrigation water to reduce soil erosion during furrow irrigation of crops. The chemical nature of PAM, together with the observation that the polymer can be biotransformed by soil bacteria, led us to question the impact of PAM treatment on the fate of coapplied agrochemicals. The herbicides, atrazine (nonionic) and 2,4-D (anionic), were tested for pesticide sorption, desorption, and degradation in PAM-treated and untreated soils. Sorption of atrazine and 2,4-D in soil was unaffected by PAMtreatment, as was atrazine desorption. However, 2,4-D desorbed more readily from the PAM-treated soil than from untreated soil. With respect to pesticide degradation, mineralization of the 2,4-D aromatic ring was not impacted by PAM treatment, but decarboxylation of the 2,4-D carboxylic acid side chain was significantly reduced in the PAM-treated soil. Limited mineralization (7 to 10%) of atrazine was observed in both soils. However, in PAMtreated soils atrazine conversion to 14CO2 and bound residue components was significantly reduced, and there was an increase in the level of methanol extractable metabolites. These results may indicate that PAM application can alter the environmental fate of some pesticides in soils, especially under the high dose treatment conditions examined in this study.
KW - 2,4-dichlorophenoxycarboxylic acid
KW - Biodegradation
KW - Erosion
KW - PAM
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U2 - 10.1080/10588330008984180
DO - 10.1080/10588330008984180
M3 - Article
AN - SCOPUS:0034033668
SN - 1058-8337
VL - 9
SP - 133
EP - 147
JO - Soil and Sediment Contamination
JF - Soil and Sediment Contamination
IS - 2
ER -