Effect of sludges on bacteria in agricultural soil. Analysis at laboratory and outdoor lysimeter scale.

The effect of composted (CS), digested (DS) and liquid raw (LRS) sludges unspiked or spiked with benzo[a]pyrene(BaPYR), dibuthyl phthalate (DBP) or nonyl phenol (NP) on the structure of the bacterial communities of an agricultural soil was estimated by using thermal temporal gel electrophoresis (TTGE). At the laboratory scale, DS and especially LRS modified the composition of the bacterial communities (irrespective of the addition of BaPYR, DBP or NP or not). Sludges, especially LRS, very probably acted both as a bacterial inoculum and a nutrient source.