Bentonite and anthracite in alginate-based controlled release formulations to reduce leaching of chloridazon and metribuzin in a calcareous soil

•Alginate-based controlled release formulations (CRFs) of herbicides were prepared.•Sorption in soil have demonstrated a high leaching potential for metribuzin.•Release rate of the herbicides was controlled by using different sorbents in CRFs.•The use of CRFs reduces leaching of chloridazon and metr...

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Bibliographic Details
Published in:Chemosphere (Oxford) 2013-08, Vol.92 (8), p.918-924
Main Authors: FLORES CESPEDES, F, PEREZ GARCIA, S, VILLAFRANCA SANCHEZ, M, FERNANDEZ PEREZ, M
Format: Article
Language:English
Subjects:
active ingredients
Adsorption
Alginate
Alginates - chemistry
bentonite
Bentonite - chemistry
Biological and medical sciences
calcareous soils
Chemical control
Chloridazon
Chromatography, High Pressure Liquid
Coal
Controlled release
Delayed-Action Preparations - chemistry
Environmental Monitoring
Environmental Pollution - prevention & control
equations
Fundamental and applied biological sciences. Psychology
Glucuronic Acid - chemistry
granules
Herbicides - chemistry
Hexuronic Acids - chemistry
Leaching
Metribuzin
Parasitic plants. Weeds
Phytopathology. Animal pests. Plant and forest protection
pollution
Pyridazines - chemistry
Soil - chemistry
Soil Pollutants - chemistry
Sorbents
sorption
Spain
Triazines - chemistry
water solubility
Weeds
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Summary:•Alginate-based controlled release formulations (CRFs) of herbicides were prepared.•Sorption in soil have demonstrated a high leaching potential for metribuzin.•Release rate of the herbicides was controlled by using different sorbents in CRFs.•The use of CRFs reduces leaching of chloridazon and metribuzin in a calcareous soil. The leaching of herbicides through soil can be minimized using controlled release formulations (CRFs). In this research, bentonite and anthracite have been used as modifying agents in alginate-based CRFs prepared with chloridazon and metribuzin. These CRFs have been evaluated in a calcareous soil. The Kf and Koc values obtained from sorption experiments in soil have demonstrated a high leaching potential for both herbicides, mainly for metribuzin. Release kinetics in soil have showed that the control of release rate of chloridazon and metribuzin was possible by using bentonite and anthracite in CRFs, being this effect greater when we use anthracite as modifying sorbent. Using an empirical equation, the time taken for 50% of the active ingredient to be released (T50(soil)) was calculated. T50 values ranged between 2.88d for metribuzin-bentonite alginate-based granules and 14.37d for chloridazon-anthracite alginate-based granules, being the release rate higher in metribuzin CRFs than in those prepared with chloridazon, which has lower water solubility. Besides, a linear correlation between T50 values in water and soil was obtained. Mobility experiments carried out in a calcareous soil have shown that the use of CRFs reduces the presence of herbicides in the leachate compared to technical products, mainly for chloridazon. We found that one could design a right profile in the release rate of active ingredients from CRFs in each agro-environmental situation, and thus prevent the environmental pollution derived from the use of chloridazon and metribuzin.
ISSN:0045-6535
1879-1298
DOI:10.1016/j.chemosphere.2013.03.001