A toxicity decrease on soil microbiota by applying the pesticide picloram anchored onto silica gel
Abstract
A route for picloram (4-amino-3,5,6-trichloropicolinic acid) immobilisation onto silica gel was established after reacting at the first stage, the precursor silylating agent 3-chloropropyltrimethoxysilane with the support. The pesticide was convalently anchored to available chloro groups of the precursor, giving 1.11 mmol g−1 of picloram per gram of silica. IR, 13C and 29Si NMR spectra are in agreement with the proposed reaction between nitrogen of the chloride group of the previously anchored silica. The immobilisation of pesticide picloram onto a silica gel surface results in a decrease in its toxicity to soil microbial activity, compared to free pesticide added to soil.