Microbial transformation of pyrethroid insecticides in aqueous and sediment phases

Abstract

Recent studies showed that synthetic pyrethroids (SPs) can move via surface runoff into aquatic systems. Fifty-six of SP-degrading bacteria strains were isolated from contaminated sediments, of which six were evaluated for their ability to transform bifenthrin and permethrin in the aqueous phase and bifenthrin in the sediment phase. In the aqueous phase, bifenthrin was rapidly degraded by strains of Stenotrophomonas acidaminiphila, and the half-life (t1/2) was reduced from >700 h to 30 to 131 h. Permethrin isomers were degraded by Aeromonas sobria, Erwinia carotovora, and Yersinia frederiksenii. Similar to bifenthrin, the t1/2 of cis- and trans-permethrin was reduced by approximately 10-fold after bacteria inoculation. However, bifenthrin degradation by S. acidaminiphila was significantly inhibited in the presence of sediment, and the effect was likely caused by strong adsorption to the solid phase. Bifenthrin t1/2 was 343 to 466 h for a field sediment, and increased to 980 to 1200 h for a creek sediment. Bifenthrin degradation in the inoculated slurry treatments was not greatly enhanced when compared with the noninoculated system. Therefore, although SP-degrading bacteria may be widespread in aquatic systems, adsorption to sediment could render SPs unavailable to the degraders, thus prolonging their persistence.

Impacts of permethrin contamination on nematode density and diversity: A microcosm study on benthic meiofauna from a Mediterranean coastal lagoon

“…The hydrobiological parameters and the nature of sediment can affect the bioavailability of pollutants (Depledge et al 1994;Langston & Spence 1994). Thus, some studies have shown that the tendency of permethrin to adsorb the fine sediments and dissolved organic matter in the marine environment (Liu et al 2004;Lee et al 2004) is likely to reduce its bioavailability to microorganisms capable of metabolizing. However sorption to fine particulate matter, bacterial biofilms and algae existing in sediments, increases the bioavailability of permethrin to benthic invertebrates (Allan et al 2005).…”

“…In fact, their half-lives in the environment typically are on the order of days to weeks in the aqueous phase (Laskowski 2002) exhibit prolonged persistence in aquatic sediments. Lee et al (2004) reported a bifenthrin half-life of 163d in a creek sediment slurry; deltamethrin was detectable in sediments of a pond mesocosm at the concentrations of 3 to 5 ng g −1 after nearly one year (Muir et al 1985) and a high concentrations of permethrin were still detected in sediment, algae and snails after four months (Dietrich et al 1996).…”

Ability of Four Emergent Macrophytes to Remediate Permethrin in Mesocosm Experiments

“…Permethrin transformation by microbes may also occur in aqueous environments. Aeromonas sobria, Erwinia carotovora, and Yersinia frederiksenii were each capable of degrading isomers of permethrin, in addition to reducing permethrin's half-life approximately 10 times (Lee et al 2004).…”

Aerobic metabolism and adsorption of pyrethroid insecticide imiprothrin in soil

“…Pyrethroids are known to undergo ester cleavage in the aid of various bacteria isolated from soils, and esterases are considered to participate in the stereoselective reaction. 26,27) Since metabolic profiles in soil have been mostly taken for pyrethroids having a 3-phenoxybenzyl moiety used for agricultural purposes, it could not be easily determined whether the rapid degradation of IP originates from substrate selectivity in microbial esterases. More availability of IP to soil microbes due to its higher water solubility than other pyrethroids may account for this difference.…”