The present study aimed to develop and prepare new
polymer/
herbicide formulations for their potential application in environment-friendly, controlled release systems of
agrochemicals. Selected biodegradable
polymers, including L-
Lactide/Glycolide/PEG/Terpolymer (PLAGA-PEG-PLAGA) as well as
oligosaccharide-based
polymers and their blend with terpolymer, were used to prepare
microspheres loaded with two soil-applied
herbicides. The degradation process of the obtained polymeric
microspheres was evaluated based on (1) their
weight loss and surface erosion and (2) the release rate of loaded
metazachlor and
pendimethalin. The herbicidal effectiveness of the
herbicides released to the soil from
microspheres was evaluated using the European Weed Research Council (EWRC) rating scale. Moreover, the ecotoxicological effect of
herbicide-loaded
microspheres buried in soil on the marine bacterial species A. fischeri was assessed. It was found that the gradual degradation rate of microparticles led to the prolonged release of both
herbicides that lasted for a few months, i.e., for the entire crop season, which is crucial in terms of
agrochemical and environmental protection.
Maltodextrin- and
dextrin-based
microspheres showed higher susceptibility to degradation than terpolymer-based
microspheres. The microencapsulation of
herbicides protected them from decomposition and excessive leaching into soil and maintained their activity for a longer period than that for non-immobilized
herbicides. The ecotoxicological assessment on A. fischeri demonstrated that the proposed
microsphere-encapsulated
herbicides were less toxic than non-immobilized
herbicides.