The microbial biodegradation of paraquat in soil

The microbial degradation of [¹⁴C]paraquat using cultures from two agricultural soils was investigated. The experiments were carried out in the absence of light, under aerobic conditions. Degradation was rapid, with 50% mineralisation to [¹⁴C]carbon dioxide occurring within three weeks. HPLC, capillary electrophoresis and mass spectroscopy confirmed that the majority (>85%) of the remaining radiochemical in solution was [¹⁴C]oxalic acid, and that no paraquat remained.