In this work, analytical study of carbofuran (CAF) and fluometuron (FLM) pesticides was carried out using direct spectrofluorimetric method in various solvents. Results showed that CAF and FLM are naturally fluorescent in all solvents under study including organic (MeOH, MeCN, DMF) and aqueous micellar one (CTAC, SDS, Brij-700). For the analysis of FLM, CTAC give the best fluorescence signal enhancement. Analytical performances, such as limit of detection (LOD) and quantification (LOQ) was evaluated after solvent optimization and were found to vary, respectively, between 0.1 and 11 ng mL and between 0.3 and 36.6 ng mL. Analytical application in various environmental aqueous samples matrices (sea, tap, runoff and well waters) give satisfactory recovery rates in the limits of 73.7-113.7% for both pesticides. This method is described for its simplicity for routine analysis.

The phenylurea herbicides are persistent in soil and water, making necessary the de-velopment of techniques for their removal from the environment. To identify new options in this regard, bacterial strains were isolated from a soil historically managed with pesticides. CD3 showed the ability to remove completely herbicides such as diuron, linuron, chlorotoluron and fluometuron from aqueous solution, and up to 89% of isoproturon. In the case of diuron and linuron, their main metabolite, 3,4-dichloroaniline (3,4-DCA), which has a higher toxicity than the parent compounds, was formed, but remained in solution without further degradation. CD3 was also tested for bioremediation of two different agricultural soils artificially contaminated with diuron, employing bioremediation techniques: (i) biostimulation, using a nutrient solution (NS), (ii) bioaugmentation, using CD3, and iii) bioavailability enhancement using 2-hydroxypropyl-β-cyclodextrin (HPBCD). When bioaugmentation and HPBCD were jointly applied, 50% of the diuron initially added to the soil was biodegraded in a range from 4.7 to 0.7 d. Also, 3,4-DCA was degraded in soil after the strain was inoculated. At the end of the soil biodegradation assay an ecotoxicity test confirmed that after inoculating CD3 the toxicity was drastically reduced.

This survey reports the monitoring of multi-pesticide residues of some fruits and vegetables sold in the local markets, sampled in 2018-2019, in the Souss Massa region in Morocco. A QuEChERS-LC-MS/MS method for 202 pesticides, belonging to different classes (carbamates, organophosphorus and organonitrogen pesticides) was applied and 51 samples were randomly bought from the local market, belonging to different products (tomato, cucumber, coriander, apricot, parsley, potato, zucchini, green bean, lettuce, strawberry and orange) and analysed for pesticide residues, which were detected in 69% of the samples, below the maximum residue limits (MRLs) for some pesticides which represent 14% of the targeted compounds. The most frequently detected compounds were acetamiprid, acibenzolar-s-methyl, abamectin, azoxystrobin, bifenazate, bitertanol, bromuconazole, butoxycarboxim, cyromazine, difenoconazole, epoxiconazole, fenbuconazole, fluometuron, linuron, metaflumizone, metconazole, metribuzin, myclobutanil, pirimicarb, pyraclostrobin, propamocarb, rotenone, trichlorfon, tebuconazole, tetraconazole, thiamethoxam and thiophanate-methyl. The obtained results provide a value to the situation of pesticide residues in Morocco.

A rapid, simple, precise and accurate high performance liquid chromatographic (HPLC) analytical method was developed and validated for the determination of the active substances (a.s.) azoxystrobin, topramezone, acetamiprid, fluometuron and folpet in their respective commercially available formulations. The method was used for the analysis of samples under the frame of the national quality control program of plant protection products in the Greek market. Chromatographic separation of the active substances from additives and co-formulants is achieved using isocratic elution with acetonitrile and 0.1% phosphoric acid solution (60:40 v/v) at a flow rate of 0.4 mL min on a C monolithic column (Chromolith Performance-RP18e 100 × 4.6 mm) and UV detection at 230 nm. Validation parameters of the method fulfilled acceptability criteria. Recovery of all individual compounds was in the range 97.8-100.9%. Precision expressed as relative standard deviation was lower than the theoretical values of the modified Horwitz equation. Correlation coefficients of linearity of response were better than 0.999. The benefits of the proposed method are significant reduction in analysis time and total cost since all analytes were determined with the same extraction procedures and chromatographic system. Analysis of real samples for all active ingredients confirmed fitness for purpose of the suggested method.

Micellar electrokinetic chromatography (MEKC) is a good separation technique with high efficiency, high selectivity and simple preparation process. Hyphenation of MEKC with mass spectrometry (MS) could extend its application in complex sample analysis. However, direct coupling MEKC using commonly used surfactants like sodium dodecyl sulfate (SDS) with ESI-MS will lead to strong signal suppression. In this work, a MEKC-MS method using volatile ammonium perfluorooctanoate as surfactant was developed. The MS compatibility of ammonium perfluorooctanoate was investigated. The result revealed that there is no signal suppression even the concentration of ammonium perfluorooctanoate was up to 300 mM. Meanwhile, we found that ammonium perfluorooctanoate used as surfactant in MEKC provided powerful F-F interaction and hydrophobic interaction, which was beneficial for separation of fluorinated compounds. Using the ammonium perfluorooctanoate based MEKC method, several groups of fluorinated compounds, which cannot be separated using non-fluorinated surfactants like lauric acid and SDS based MEKC method, were baseline separated. Finally, the MEKC-ESI-MS method was successfully applied for analysis of two herbicides including fluometuron and fenuron in lake water samples with high separation efficiency, high sensitivity, good linearity and reproducibility.

The accumulation of toxic chemical constituents in sludge and wastewater has fuelled an interest in investigating efficient and eco-friendly wastewater remediation approaches. In this study, a set of bacterial samples were isolated from petroleum sludge and tested for their ability to degrade different aromatic pollutants, including azo dyes and emerging pollutants. Although exhibiting differential specificity, all bacterial isolates were able to degrade different classes of aromatic dyes efficiently. Ribosomal 16S rRNA sequencing of the 12 bacterial isolates showed that they belonged to two different bacterial genera: Bacillus cereus and Pseudomonas guariconensis. Of these 12 strains, MA1 (B. cereus) was the most promising and was chosen for further optimization and biochemical studies. The optimum culture and remediation conditions for MA1 was found to be at pH 7, with 100 ppm dye concentration, and under aerobic condition. In addition to efficiently degrading various aromatic dyes (e.g. Congo Red, Reactive Black 5, PBS, and Toluidine Blue), MA1 was also found to be capable of degrading various emerging pollutants (e.g. prometryn, fluometuron and sulfamethoxazole). Preliminary transcriptome analysis shows that MA1 grown on media containing a mixture of aromatic dyes appears to differentially express a number of genes. Data shown here strongly suggests that petroleum sludge is a rich reservoir of bacteria with powerful remediation abilities.

Four phenylurea herbicides (PUHs) were assessed for degradation and transformation into N-nitrosodimethylamine (NDMA) under three oxidation conditions (chlorine (Cl), chlorine dioxide (ClO), and ozone (O)) from an aqueous solution. Removal ratios correlated with the numbers of halogen elements contained in PUHs (isoproturon  > chlorotoluron  > diuron  > fluometuron ), and the degradation efficiencies of oxidants from fastest to slowest were: O, ClO, and Cl. NDMA can be generated directly from the ozonation of PUHs. Further, compared with chloramination alone, ozonation prominently promoted NDMA formation potential (NDMA-FP) during post-chloramination, and NDMA-FPs increased approximately 23-68 times than those during ozonation only at 2.5 mg/L O over 10 min; molar yields of NDMA from highest to lowest were 11.1% (isoproturon), 1.17% (chlorotoluron), 1.0% (diuron), and 0.73% (fluometuron). The PUH degradation kinetics data during ozonation agreed with the pseudo-first-order model. The rate constant k were 0.31 × 10-19.8 × 10 s. The k and removal ratios of PUHs during ozonation partially scaled with the mass, LogK, and Henry's constants of PUHs. Comparisons of measured NDMA-FPs with calculated NDMA-FPs from residual PUH after oxidation showed that the intermediates produced during ozonation facilitated NDMA-FPs; this contribution was also observed for chlorotoluron and isoproturon during ClO oxidation. Examination of reaction mechanisms revealed that tertiary amine ozonation, N-dealkylation, hydroxylation, the cleavage of N-C bonds, ammonification, and nitrification occurred during the ozonation of PUHs, and the dimethylamine (DMA) functional groups could be decomposed directly and transformed into NDMA via the formation of the intermediate unsymmetrical dimethylhydrazine. NDMA is also formed from the reaction between DMA and phenylamino-compounds. Clarifying primary degradation products of PUHs and transformation pathways of NDMA during oxidation processes is useful to optimize treatment processes for water supplies.

Prototypes of on-site automatic photo induced fluorescence detectors of pesticide in natural waters are set up and applied for the determination of the benzoyl- and phenylurea pesticides, namely fluometuron, monolinuron and diflubenzuron. As these pesticides present no native fluorescence the set up system use the photo conversion under UV irradiation of these pesticides into highly fluorescent photoproducts. A first system, called AUTOPIF, (evolution the commercial AQUAPOD system) is develop using a detection via a diode array spectrometer. To improve the sensitivity of the method, a second system, called AUTOPIF+, is developed with a more resolute spectrometer and an intensified CCD camera detection. Analytical applications were carried out in aqueous solution and detected on line with the AUTOPIF and AUTOPIF+ system. The calibration curves are linear over one order of magnitude, and the limits of detection are in the μg mL range. The analytical performances of these methods for the determination of the three pesticides are satisfactory in comparison to other classical PIF methods published for the determination of phenylurea pesticides in aqueous solutions. Our results show that the AUTOPIF and AUTOPIF+ methods are versatile, sensible and can be easily applied as an alert system to detect pollutant residues in naturals waters over a threshold value.

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance fluometuron. To assess the occurrence of fluometuron residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Commission Regulation (EC) No 33/2008 as well as the European authorisations reported by Member States (including the supporting residues data). Based on the assessment of the available data, an MRL proposal was derived and a consumer risk assessment was carried out. All information required by the regulatory framework was present and a risk to consumers was not identified. In addition, EFSA identified some data gaps which are not expected to impact on the validity of the MRL derived but which might have an impact on national authorisations.

Based on the structural features of fluometuron, an immunizing hapten was synthesized and conjugated to bovine serum albumin as an immunogen to prepare a polyclonal antibody. However, the resultant antibody indicated cross-reactivity with 6 structurally similar phenylurea herbicides, with binding activities (expressed by IC values) ranging from 1.67 µg/L to 42.71 µg/L. All 6 phenylurea herbicides contain a common moiety and three different substitutes. To understand how these three different chemical groups affect the antibody-phenylurea recognition activity, quantum chemistry, using density function theory (DFT) at the B3LYP/6-311++ G(d,p) level of theory, was employed to optimize all phenylurea structures, followed by determination of the 3D conformations of these molecules, pharmacophore analysis, and molecular electrostatic potential (ESP) analysis. The molecular modeling results confirmed that the geometry configuration, pharmacophore features and electron distribution in the substituents were related to the antibody binding activity. Spearman correlation analysis further elucidated that the geometrical and electrostatic properties on the van der Waals (vdW) surface of the substituents played a critical role in the antibody-phenylurea recognition process.