Soil Microbial Effects on the Stereoselective Mineralization, Extractable Residue, Bound Residue, and Metabolism of a Novel Chiral Cis Neonicotinoid, Paichongding

Abstract

Fate characteristics of the four stereoisomers of paichongding [IPP, 1-((6-chloropyridin-3-yl)methyl)-7-methyl-8-nitro-5-propoxy-1,2,3,5,6,7-hexahydroimidazo[1,2-a]pyridine] in aerobic sterilized and nonsterilized fluvio-marine yellow loamy soil were investigated using a (14)C tracer technique combined with HPLC and LC-MS/MS. Results showed that the mineralization and bound residue (nonsterile/sterilized soil, % of applied amount) of four stereoisomers of IPP were 1.76-6.10/0.33-0.82 and 12.01-31.20/6.58-20.81 at 100 days after treatment. Seven and five incomplete intermediates of IPP were detected in nonsterilized and sterilized soil, respectively, and a possible degradation pathway was proposed. Degradation mainly occurred on the tetrahydropyridine ring, including oxidation and elimination of the methyl, propyl, and nitro groups. All of these results suggest that soil microbial activity greatly contributes to the epimeride-selective mineralization, formation of bound residue, and degradation of IPP in loamy soil. The identified transformation intermediates could be used for further study on their toxicity to target and nontarget species.

Toxic effect of the novel chiral insecticide IPP and its biodegradation intermediate in nematode Caenorhabditis elegans

“…The toxicity differences between IPP and M1 at relatively high concentrations also occurred with the aid of head thrash, body bend, locomotion and lifespan. M1 is one of the intermediates of IPP biodegradation in environment, and also determined in soil after IPP application (Cai et al 2015a(Cai et al , 2015b(Cai et al , 2016a(Cai et al , 2016b(Cai et al , 2016cChen et al 2017;Fu et al 2013). The toxicity of toxicants in C. elegans is similar to the toxic results in mammals, the results in this study imply the possible potential more severe toxicity of IPP than M1 in mammals.…”

“…Paichongding (IPP, 1-((6-chloropydidin-3-yl) methyl)-7-methyl-8-nitro-5 -propoxy-1,2,3,5,6,7-hexahydroimidazo[1,2--]-pyridine), is a novel chiral insecticide with independent intellectual property rights developed in China (Cai et al, 2015a(Cai et al, , 2015b(Cai et al, , 2016aFu et al 2013). It has higher insecticidal activity (40-50 times) compared to imidacloprid-resistance pests, and also has low toxicity to human.…”

Eukaryal composition and diversity in anaerobic soils influenced by the novel chiral insecticide Paichongding

“…IPP could make some of phyla and genus increase or decrease in soils. These variation was presumably due to IPP spraying and properly accumulation of IPP metabolites in soils (Cai et al 2015a , b , 2016a , b ; Fu et al 2013 ; Li et al 2013 ; Wang et al 2013 ). The heatmap also revealed clearly that the eukaryal communities were different in same soil (Fig.…”

“…Paichongding (IPP, 1-((6-chloropydidin-3-yl) methyl)-7-methyl-8-nitro-5propoxy-1,2,3,5,6,7-hexahydroimidazo[1,2-α-]-pyridine), is a novel neonicotinoid insecticide with independent intellectual property rights (Cai et al 2016a , b , c ; Fu et al 2013 ). It has four stereoisomers ( RR , SS , RS and SR -IPP) because of its two chiral carbon centers.…”

“…IPP has higher insecticidal activity (40–50 times) compared to imidacloprid-resistance pests, and also has low toxicity to human. In 2009, IPP production in China has reached 1000 tons and was sprayed for almost 3.3 million hectares (Fu et al 2013 ).…”