Insights into the Toxicity and Degradation Mechanisms of Imidacloprid Via Physicochemical and Microbial Approaches

Abstract

Imidacloprid is a neonicotinoid insecticide that has been widely used to control insect pests in agricultural fields for decades. It shows insecticidal activity mainly by blocking the normal conduction of the central nervous system in insects. However, in recent years, imidacloprid has been reported to be an emerging contaminant in all parts of the world, and has different toxic effects on a variety of non-target organisms, including human beings, due to its large-scale use. Hence, the removal of imidacloprid from the ecosystem has received widespread attention. Different remediation approaches have been studied to eliminate imidacloprid residues from the environment, such as oxidation, hydrolysis, adsorption, ultrasound, illumination, and biodegradation. In nature, microbial degradation is one of the most important processes controlling the fate of and transformation from imidacloprid use, and from an environmental point of view, it is the most promising means, as it is the most effective, least hazardous, and most environmentally friendly. To date, several imidacloprid-degrading microbes, including Bacillus, Pseudoxanthomonas, Mycobacterium, Rhizobium, Rhodococcus, and Stenotrophomonas, have been characterized for biodegradation. In addition, previous studies have found that many insects and microorganisms have developed resistance genes to and degradation enzymes of imidacloprid. Furthermore, the metabolites and degradation pathways of imidacloprid have been reported. However, reviews of the toxicity and degradation mechanisms of imidacloprid are rare. In this review, the toxicity and degradation mechanisms of imidacloprid are summarized in order to provide a theoretical and practical basis for the remediation of imidacloprid-contaminated environments.

Bacterial Enrichment Cultures Biotransform the Mycotoxin Deoxynivalenol into a Novel Metabolite Toxic to Plant and Porcine Cells

“…Out of the five start products, which have no apparent connection to DON exposure, products B and E, were able to biotransform the mycotoxin completely, starting from the first enrichment. During the subsequent enrichments of product B, a shift in bacterial community was observed towards mainly the genera Sphingopyxis , Pseudoxanthomonas , Ochrobactrum and Pseudarthrobacter , which are known for their biodegradation capabilities of complex molecules, such as (polycylic) aromatic hydrocarbons [ 62 , 63 , 64 , 65 , 66 , 67 , 68 ], neonicotinoid insecticides [ 69 ], cyanobacterial toxins [ 66 , 70 , 71 ], phthalate esters [ 72 ], polyhydroxyalkanoates [ 73 ], nitrophenols [ 74 ], 2,4,6-trinitrotoluene [ 75 ], etc. The classes to which these genera belong, the α-, γ-proteobacteria and Actinobacteria, are also linked to the bioremediation and biodegradation of other mycotoxins such as aflatoxins, fumonisins, zearalenone and ochratoxins [ 76 , 77 , 78 , 79 ].…”

Emerging Technologies for Degradation of Dichlorvos: A Review

“…Microbial degradation is regarded as a cost-effective and promising method with a huge potential for the removal of pesticides, compared to physicochemical approaches [ 9 , 13 , 19 ]. Soil bacteria and fungi have been documented as being able to mineralize various organic pollutants as a sole carbon source [ 56 , 57 , 58 , 59 , 60 ].…”

“…Several microbes, including Cunninghamell aelegans , Fusarium solani , Talaromyces atroroseus , Aspergillus oryzae , Ochrobactrum intermedium , Pseudomonas aeruginosa , and Penicillium sp., have been isolated and play vital roles in DDVP degradation. It has been reported that the organic pollutants can be used by edaphon including soil bacteria and soil fungi as a sole carbon source [ 9 , 10 , 11 , 12 , 13 ]. These studies showed that microbial degradation seems to be a more environmentally friendly and convenient treatment method to reduce hazardous effects of toxic pollutants or contaminants [ 14 , 15 , 16 , 17 , 18 , 19 ].…”

Impacts of Neonicotinoids on Molluscs: What We Know and What We Need to Know

“…The rate of degradation of neonicotinoids varies according to microbial community composition and function [ 77 ]. Using controlled experimental conditions in the laboratory, Anhalt et al [ 78 ] reported that Leifsonia strain PC-21 degraded up to 58% from 25 mg/L imidacloprid within three weeks in trypsin solution containing 1 g/L succinate and D-glucose at 27 °C while the control (i.e., without Leifsonia strain PC-21) had no degradation of imidacloprid.…”