The influence of soil contaminant kinetics on earthworm activity was studied in experimental soil columns with controlled parameters (microcosms). At first, aldicarb kinetics was studied for 75 days. At the same time, activities of Aporrectodea caliginosa were recorded in uncontaminated soil samples. After 15 days, aldicarb disappears and is replaced by aldicarb sulfoxide. One sample of earthworms was set in contact with aldicarb (phase 1), then a second one with aldicarb sulfoxide (phase 2). A disturbance of the activities of earthworms was observed when aldicarb was present but did not seem to exist with aldicarb sulfoxide. -from Authors