The behavior of clomazone in the soil environment.
Pest Manag Sci
; 65(6): 711-6, 2009 Jun.
Article
em En
| MEDLINE
| ID: mdl-19319928
ABSTRACT
BACKGROUND:
Clomazone is a herbicide used to control broadleaf weeds and grasses. Clomazone use in agriculturally important crops and forests for weed control has increased and is a potential water contaminant given its high water solubility (1100 microg mL(-1)). Soil sorption is an environmental fate parameter that may limit its movement to water systems. The authors used model rice and forest soils of California to test clomazone sorption affinity, capacity, desorption, interaction with soil organic matter and behavior with black carbon.RESULTS:
Sorption of clomazone to the major organic matter fraction of soil, humic acid (HA) (K(d) = 29-87 L kg(-1)), was greater than to whole soils (K(d) = 2.3-11 L kg(-1)). Increased isotherm non-linearity was observed for the whole soils (N = 0.831-0.893) when compared with the humic acids (N = 0.954-0.999). Desorption isotherm results showed hysteresis, which was greatest at the lowest solution concentration of 0.067 microg mL(-1) for all whole soils and HA extracts. Aliphatic carbon content appeared to contribute to increased isotherm linearity.CONCLUSION:
The results indicate that clomazone does not sorb appreciably to sandy or clay soils. Its sorption affinity and capacity is greater in humic acid, and consequently clomazone has difficulty desorbing from soil organic matter. Sorption appears to follow processes explained by the dual-mode model, the presence of fire residues (black carbon) and a recently proposed sorption mechanism.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Solo
/
Oxazolidinonas
/
Herbicidas
/
Isoxazóis
Idioma:
En
Revista:
Pest Manag Sci
Assunto da revista:
TOXICOLOGIA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Estados Unidos