Degradation of the anilide fungicide inpyrfluxam in illuminated water–sediment systems

抄録

The degradation behavior of inpyrfluxam (1) was investigated in aerobic aquatic water–sediment systems exposed to continuous artificial sunlight (λ>290 nm). Under irradiation in the presence of sediment, 1 preferentially underwent oxidation at the 1′- and 3′-positions of the indane ring, followed by cleavage of the amide linkage with the half-life of 16–18 days, and finally mineralized to carbon dioxide or exhibited extremely strong adsorption to sediment. Especially, as compared to systems kept in darkness, carboxylation at the 1′-position of the indane ring was remarkably accelerated in illuminated water–sediment systems and the aqueous photodegradation study due to the presence of photosynthetic microorganisms in the sediment soil. No significant degradation products were observed in the water–sediment in darkness and in the sterilized water–sediment under irradiation throughout the study. The fate of 1 and its degradation products in illuminated water–sediment systems was considered to better reflect realistic conditions, as it accounts for various effects attributed to sunlight, such as the presence of photosynthetic microorganisms.