Variability of pesticide mineralization in individual soil aggregates of millimeter size

The aim of this study was to compare the 2,4-D mineralization in individual aggregates of millimeter size (3 size classes and 96 aggregates per size class). 14 CO 2 coming from the mineralization of 14 C ring-labeled 2,4-D and evolved by each aggregate incubated in microtiter plates was trapped with barium hydroxide on filters and measured using a Phosphorimager. We observed an important variability of mineralization in aggregates of each size class and in the different size classes of aggregates. The main factors responsible for these fluctuations could be a heterogeneous distribution of degrading microorganisms or of available carbon necessary for cometabolism.