Degradation Of Bifenthrin Research Articles

Simultaneous biodegradation of bifenthrin and chlorpyrifos by Pseudomonas sp. CB2

ABSTRACTThe degradation of bifenthrin (BF) and chlorpyrifos (CP), either together or individually, by a bacterial strain (CB2) isolated from activated sludge was investigated. Strain CB2 was identified as belonging to genus Pseudomonas based on the morphological, physiological, and biochemical characteristics and a homological analysis of the 16S rDNA sequence. Strain CB2 has the potential to degrade BF and CP, either individually or in a mixture. The optimum conditions for mixture degradation were as follows: OD600nm = 0.5; incubation temperature = 30°C; pH = 7.0; BF-CP mixture (10 mg L−1 of each). Under these optimal conditions, the degradation rate constants (and half-lives) were 0.4308 d−1 (1.61 d) and 0.3377 d−1 (2.05 d) for individual BF and CP samples, respectively, and 0.3463 d−1 (2.00 d) and 0.2931 d−1 (2.36 d) for the BF-CP mixture. Major metabolites of BF and CP were 2-methyl-3-biphenylyl methanol and 3,5,6-trichloro-2-pyridinol, respectively. No metabolite bioaccumulation was observed. The ability of CB2 to efficiently degrade BF and CP, particularly in a mixture, may be useful in bioremediation efforts.

The Effect of Different Medium on Enantioselectivity in Degradation of Bifenthrin.

Bifenthrin (BF) is a chiral pesticide with two enantiomers. In this work, its stereoselective degradation was investigated in plants and domesticated active sludge. Considering that the degradation to pesticides of plants was effected by external conditions, hence, nanometer materials (gothite) were added into soil to explore the effect of sorption on enantioselectivity in degradation of BF. The microbial community that was responsible for BF-biodegrading in active sludge was studied by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE). In plant researches, chiral difference was discovered in the degradation of pesticides that onions resulted in. The existence of gothite in soil not only reduced the amount of BF that plants uptake from the environment, but it also enlarged the chiral difference during the process, indicating that the absorption of gothite to pesticides had enantioselectivity, which may be generated by that adsorption site where BF combined with gothite located in the chiral center of the pesticide. In studies of sludge, BF can be effectively degraded and decline of both isomers followed first-order kinetics. However, there was no obvious stereoselective degradation in domesticated sludge. The analysis of DGGE revealed that active sludge maintained the rich microbial community in the whole process (H > 3). The H index increased in the early domestication, which may because BF had no direct toxicity to the bacteria. The bacteria were able to degrade the small dose of the pesticide and absorbed it as nutrition. The sequence results demonstrated that the variety of bacteria grew, instead of Acidobacteria, Betaproteobacteria, Sphingobacteriia and Alphaproteobacteria, Flavobacteria also appearing in sludge after domestication.

Degradation of bifenthrin and pirimiphos-methyl residues in stored wheat grains (Triticum aestivum L.) by ozonation

Pesticide insecticides are used on wheat grains in storage units but their efficiency is hindered by persistent residues in the grains. Therefore, this study aims to evaluate the effectiveness of ozone (O3) gas treatment on the degradation of residual bifenthrin and pirimiphos-methyl insecticides commonly used in storage wheat grains, as well as to evaluate degradation of their by-products. The residues of bifenthrin decreased after 180min of exposure in a concentration of 60μmol/mol (a 37.5±7.4% reduction) with 20% moisture content and 0.9 water activity. On the other hand, under the same experimental conditions, the pirimiphos-methyl residues significantly decreased in the wheat grains (71.1±8.6%) after 30min of exposure. After O3 gas treatment, three by-products of pirimiphos-methyl (m/z=306.1) containing different molecular mass to charge ratios (m/z=278.1, 301.1 and 319.2) were identified by LC–MS. O3 is a strong oxidizer that has shown the potential to reduce pesticide residues in stored grain in order to ensure food quality and safety.

ISOLATION AND CHARACTERIZATION OF BIFENTHRIN CATABOLIZING BACTERIAL STRAIN <i>BACILLUS CIBI</i> FROM SOIL FOR PYRETHROIDS BIODEGRADATION

Pyrethroids are commonly used in most parts of the world and are reported to have potential health ris ks. Bifenthrin, a third generation pyrethroid used as i nsecticide has caused potential effect on aquatic l ife and human health. Bioremediation is a practical approac h to reduce pesticide in the environment and report s of microbial degradation of bifenthrin are meagre. This study was aimed at isolating and characterizin g bacterial isolates for the efficient removal of bif enthrin residues in the environment. A bacterial st rain PGS-4 isolated from sewage of pesticide industry wa s tested for growth at higher concentration of bifenthrin (800 mg L -1 ) and the optimum pH and temperature were determined. The strain utilized bifenthrin as sole carbon source for growth over a wide range of pH (4.0-9.0) and temperatures (1637°C). On the basis of growth kinetics studies, the optimal conditions were determined to be pH 7.0-8. 0 and 30°C. 16S rRNA gene sequence analysis showed that strain PGS-4 forms a distinct phylogenetic lineage within the evolutionary radiation encompass ed by the genus Bacillus and showed 99% similarity to that of Bacillus cibi. This study depicts the ability of B. cibi to utilize bifenthrin at higher concentration under in vitro thereby can be used in eliminating bifenthrin from contaminated soils as a practical approach to reduce pyrethroid toxicity in the environment.

Study on the residue and degradation of fluorine-containing pesticides in Oolong tea by using gas chromatography–mass spectrometry

The natural degradation of pyrethroids pesticides (bifenthrin and cyhalothrin) and benzoylurea pesticides (teflubenzuron, flufenoxuron and chlorfluazuron) in the leaves of Oolong tea trees and the effect of processing steps and pesticide's dose on the residue of above five pesticides in dried Oolong tea leaf samples were studied in detail by farm experiment and gas chromatography–mass spectrometry. The experimental results showed that: 1) Higher pesticide's dose used in tea planting will result in higher residue of pesticides in dried Oolong tea leaf samples, but the dose did not affect the degradation rate of pesticide. 2) The degradation of bifenthrin, cyhalothrin, teflubenzuron, flufenoxuron and chlorfluazuron in the leaves of tea trees follows zero-order kinetics with a half-life of 9.3–9.4, 10.2–10.4, 9.2–9.6, 12.1–13.5 and 7.0–8.2 days respectively, suggested that the pesticide's dose and the interval between tea picking and pesticide spraying are two key factors on the residue of fluorine-containing pesticides in dried Oolong tea leaf samples. 3) In comparison with bifenthrin, cyhalothrin, teflubenzuron and flufenoxuron, chlorfluazuron is more difficult to be remained in dried Oolong tea leaf samples. 4) The pesticide residue was not affected by the processing steps except the fermentation step in which the benzoylurea insecticides and bifentrin were partially lost or degraded. The results of this study are helpful for farmer to safely use fluorine-containing pesticides in Oolong tea planting.

The influence of small- and large-scale composting on the dissipation of pesticide residues in a biopurification matrix

Pesticides are efficiently retained and degraded in the organic matrix of a biopurification system. However, as this matrix mineralizes slowly over time, nutrients will start to become depleted and thus a decay in biomass will probably occur. At that moment, the efficiency of the system decreases and the matrix should be replaced. The spent matrix might still contain residues of pesticides. Hence treatment of this matrix is essential. In this study we opted to use composting or incubation as an effective and environmentally friendly treatment strategy. Small- and large-scale composting/incubation trials were set up to treat the presence of linuron, bentazone, metalaxyl and bifenthrin in a contaminated matrix. Large-scale composting, performed in an industrial composting facility, resulted in decreased concentrations of metalaxyl, linuron and bentazone. Degradation of bifenthrin was very limited. In the small-scale incubation process, a decrease in concentration was noted for bifenthrin, metalaxyl and bentazone. A reduction in extractable pesticide concentration does not, however, always indicate degradation but could be attributed to the formation of non-extractable residues. Industrial and small-scale composting/incubation reduced the concentration of some pesticides during the timeframe studied, although little reduction was obtained for the persistent pesticide bifenthrin in the industrial composting process and for linuron in barrel incubation.

The Fate of Bifenthrin and Fipronil in Pine Bark Nursery Media

Bifenthrin and fipronil are important pesticides used in the nursery industry for the control of imported fire ants. Our research measured the influence of irrigation frequency and time on the degradation of bifenthrin and fipronil in pine bark nursery medium. Pine bark media leachates were collected over a 180-d period. Levels of bifenthrin, fipronil, and metabolites of fipronil (MB 46513, MB 45950, MB 46136) were measured using gas chromatography and mass spectrophotometery. Bifenthrin leachate concentrations decreased from 60 ppb on day 1 to ≈1 ppb after 120 d. Fipronil leachate concentrations decreased from 40 ppb on day one to a low of 15 ppb after 120 d. In contrast, metabolites MB 45950 and MB 46136 gradually increased over the 180-d period. Metabolite MB 46513 was not detected during the experiment. Pine bark medium leachate concentrations of bifenthrin and fipronil were greater than previously reported levels in pure water. We theorize that organic compounds present in pine bark may have increased the solubility of these chemicals.

Degradation of bifenthrin, chlorpyrifos and imidacloprid in soil and bedding materials attermiticidal application rates

Degradation of bifenthrin, chlorpyrifos and imidacloprid in soil and bedding materials attermiticidal application rates