Biodegradation of Aged Residues of Atrazine and Alachlor in a Mix-Load Site Soil by Fungal Enzymes

Abstract EN

Soils from bulk pesticide mixing and loading (mix-load) sites are often contaminated with a complex mixture of pesticides, herbicides, and other organic compounds used in pesticide formulations that limits the success of remediation efforts.

Therefore, there is a need to find remediation strategies that can successfully clean up these mix-load site soils.

This paper examined the degradation of atrazine (2-chloro-4-ethylamino-6-isopropylamino-S-triazine; AT) and alachlor (2-chloro-2′, 6′-diethyl-N-[methoxymethyl]-acetanilide) in contaminated mix-load site soil utilizing an extracellular fungal enzyme solution derived from the white rot fungus, Phanerochaete chrysosporium, grown in a packed bed bioreactor.

Thirty-two percent of AT and 54% of AL were transformed in the biometers.

The pseudo first-order rate constant for AT and AL biodegradation was 0.0882 d-1 and 0.2504 d-1, respectively.

The half-life (t1/2) for AT and AL was 8.0 and 3.0 days, respectively.

Compared to AT, the initial disappearance of AL proceeded at a faster rate and resulted in a greater amount of AL transformed.

Based on the net Co2 evolved from the biometers, about 4% of the AT and AL initially present in the soil was completely mineralized.