Prevention of chloridazon and metribuzin pollution using lignin-based formulations

The herbicides chloridazon and metribuzin, identified as groundwater pollutants, were incorporated in lignin-based granules with different sizes to obtain controlled release formulations (CRFs) and reduce water pollution risk. Kinetics release tests in water and soil showed that the release rate of both from CRFs diminished in comparison to technical products. A linear correlation was obtained between the time taken for 50% of the active ingredient to be released (T₅₀) into water and granule size of the CRFs. Besides, a linear correlation was reached between T₅₀ values in water and soil. Mobility experiments carried out in calcareous soil show that the use of lignin-based CRFs reduces the presence of both herbicides in the leachate compared to the technical grade products. The set of experiments developed in this research can be useful to design, prepare and evaluate formulations with CR properties which can reduce the pollution derived from the use of herbicides.