The evaluation of
pesticide-mineralising microorganisms to clean-up contaminated
soils was studied with the widely applied and easily detectable compound
atrazine, which is rapidly mineralised by several microorganisms including the Pseudomonas sp. strain Yaya 6. The rate of
atrazine removal was proportional to the water content of the soil and the amount of bacteria added to the soil. In soil slurry, 6 mg
atrazine kg soil-1 was eliminated within 1 day after application of 0.3 g dry weight inoculant biomass kg soil-1 and within 5 days when 0.003 g kg soil-1 was used. In partially saturated soil (60% of the maximal water-holding capacity) 15 mg
atrazine kg soil-1 was used. In unsaturated soil, about 60% [U-ring-14C]
atrazine was converted to 14CO2 within 14 days.
Atrazine was very efficiently removed by the inoculant biomass, not only in soil that was freshly contaminated but also in soil aged with
atrazine for up to 260 days. The bacteria exposed to
atrazine in unsaturated sterile soil were still active after
starvation period of 240 days: 15 mg newly added
atrazine kg soil-1 was eliminated within 5 days.