Preferential dealkylation reactions of s-triazine herbicides in the unsaturated zone
Environmental Science & Technology
By: M. S. Mills and Thurman E. Michael
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Abstract
The preferential dealkylation pathways of the s-triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine], and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine], and two monodealkylated triazine metabolites, deisopropylatrazine (DIA: 2-amino-4-chloro-6-ethylamino-s-triazine) and deethylatrazine (DEA: 2-amino-4-chloro-6-isopropylamino-s-triazine) were investigated on two adjacent Eudora silt-loam plots growing corn (Zea mays L.). Results from the shallow unsaturated zone and surface-water runoff showed preferential removal of an ethyl side chain from atrazine, simazine, and DIA relative to an isopropyl side chain from atrazine, propazine, and DEA. It is hypothesized that deethylation reactions may proceed at 2-3 times the rate of deisopropylation reactions. It is concluded that small concentrations of DIA reportedly associated with the degradation of atrazine may be due to a rapid turnover rate of the metabolite in the unsaturated zone, not to small production levels. Because of continued dealkylation of both monodealkylated metabolites, a strong argument is advanced for the presence of a didealkylated metabolite in the unsaturated zone.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Preferential dealkylation reactions of s-triazine herbicides in the unsaturated zone |
| Series title | Environmental Science & Technology |
| DOI | 10.1021/es00053a011 |
| Volume | 28 |
| Issue | 4 |
| Year Published | 1994 |
| Language | English |
| Publisher | ACS |
| Contributing office(s) | Toxic Substances Hydrology Program |
| Description | 6 p. |
| First page | 600 |
| Last page | 605 |
| Google Analytic Metrics | Metrics page |