Biodegradation of atrazine in sand sediments and in a sand-filter

The potential of a microbial consortium for treating waters contaminated wi th atrazine was considered. In conventional liquid culture, atrazine and it s two dealkylated by-products were equally metabolised by the microbial con sortium. Transient production of hydroxyatrazine was observed during atrazi ne catabolism, indicating that the catabolic pathway was similar to the one reported for isolates capable of atrazine mineralisation. This consortium was then inoculated to sediments sampled from an artificial recharge site. These sediments were contaminated by atrazine and diuron and exhibited only a slow endogenous herbicide dissipation. Inoculated microorganisms led to extensive atrazine degradation and survived for more than 10 weeks in the s ediments. A rudimentary bioreactor was then setup using a soil core origina ting from the same recharge site. Degrading microorganisms rapidly colonise d the core and expressed their degrading activity. The efficiency of the bi oreactor was improved in the presence of spiked environmental surface water s. Atrazine degraders thus possibly benefited from the other organic source s in developing and expressing their activity. The microbial consortium did not initially exhibit the capacity to degrade diuron, which was used as re ference compound. No change in this characteristic was detected throughout the study.