Adsorption and degradation of phenoxyalkanoic acid herbicides in soils: A review
The primary aim of the present review on phenoxyalkanoic acid herbicides—2‐(2,4‐dichlorophenoxy) acetic acid (2,4‐D), 2‐(4‐chloro‐2‐methylphenoxy) acetic acid (MCPA), (2R)‐2‐(2,4‐dichlorophenoxy) propanoic acid (dichlorprop‐P), (2R)‐2‐(4‐chloro‐2‐methylphenoxy) propanoic acid (mecoprop‐P), 4‐(2,4‐di...
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Published in | Environmental toxicology and chemistry Vol. 35; no. 2; pp. 271 - 286 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Pergamon
01.02.2016
Blackwell Publishing Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | The primary aim of the present review on phenoxyalkanoic acid herbicides—2‐(2,4‐dichlorophenoxy) acetic acid (2,4‐D), 2‐(4‐chloro‐2‐methylphenoxy) acetic acid (MCPA), (2R)‐2‐(2,4‐dichlorophenoxy) propanoic acid (dichlorprop‐P), (2R)‐2‐(4‐chloro‐2‐methylphenoxy) propanoic acid (mecoprop‐P), 4‐(2,4‐dichlorophenoxy) butanoic acid (2,4‐DB), and 4‐(4‐chloro‐2‐methylphenoxy) butanoic acid (MCPB)—was to compare the extent of their adsorption in soils and degradation rates to assess their potential for groundwater contamination. The authors found that adsorption decreased in the sequence of 2,4‐DB > 2,4‐D > MCPA > dichlorprop‐P > mecoprop‐P. Herbicides are predominantly adsorbed as anions—on organic matter and through a water‐bridging mechanism with adsorbed Fe cations—and their neutral forms are adsorbed mainly on organic matter. Adsorption of anions of 2,4‐D, MCPA, dichlorprop‐P, and mecoprop‐P is inversely correlated with their lipophilicity values, and modeling of adsorption of the compounds based on this relationship is possible. The predominant dissipation mechanism of herbicides in soils is bacterial degradation. The contribution of other mechanisms, such as degradation by fungi, photodegradation, or volatilization from soils, is much smaller. The rate of bacterial degradation decreased in the following order: 2,4‐D > MCPA > mecoprop‐P > dichlorprop‐P. It was found that 2,4‐D and MCPA have the lowest potential for leaching into groundwater and that mecoprop‐P and dichlorprop‐P have slightly higher potential. Because of limited data on adsorption and degradation of 2,4‐DB and MCPB, estimation of their leaching potential was not possible. Environ Toxicol Chem 2016;35:271–286. © 2015 SETAC |
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Bibliography: | http://dx.doi.org/10.1002/etc.3212 istex:DDFE724D543434EE09E04D8168A8283AD0BBD235 Ministry of Science and Higher Education ark:/67375/WNG-NMBMQ0LZ-4 ArticleID:ETC3212 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0730-7268 1552-8618 |
DOI: | 10.1002/etc.3212 |