. A 400 g of moist soil was
weighed into a 1 L amber glass flask with PTFE-lined caps
(Wheaton, USA). Twenty mL of 100 mg L ?1 (for initial soil concentration of 5 m g g ?1 ) or 500 mg L ?1 (for initial soil concentration
of 25 m g g ?1 ) chlorpyrifos solutions (in acetone) were added to one
quarter of the soils, left for half an hour to allow the acetone to
evaporate and then mixed with the rest of the soils.