Removal of benzophenone-4 via chlorination and advanced oxidation processes in aqueous solution: kinetics, by-product identification, and mechanistic studies

Benzophenone-4 (BP-4) is one of the UV filters widely used in personal care products (PCPs). BP-4 has been identified as an emergent contaminant detected in influent and effluent of wastewater treatment plants (WWTPs) at high concentrations showing that conventional treatment is unable to remove it, subsequently, the presence of BP-4 in surface water is inevitable. In this study, we focus on the degradation of this compound by chlorine, and we report the efficiency of its removal from water by applying two advanced oxidation processes UV/TiO2 and UV/H2O2 aiming to achieve a superior mineralization result. The study was performed in purified water (pH = 6.5, temperature = 25 °C) with an initial concentration of BP-4 similar to that detected in WWTPs (10 mg/L). The results showed that 76% of BP-4 was degraded after 80 min of reaction with chlorine leading to the formation of one by-product persistent in the solution. The oxidation by UV/TiO2 and UV/H2O2 led to a total removal of BP-4 and their generated by-products after 50 and 10 min of reactions, respectively. The kinetic study showed that BP-4 degradation by UV/H2O2 and UV/TiO2 followed pseudo-first-order reaction kinetics and the apparent rate constants (kapp) were determined to be 0.48 min-1 and 0.08 min-1, respectively. The degradation of BP-4 by chlorine followed first-order reaction kinetics with kapp = 0.02 min-1. The identification of by-product structures was performed using liquid chromatography with electrospray ionization and tandem mass spectrometry (MS/MS. The fragmentation of BP-4 and by-product ions at different collision energies allowed to propose the pathways of degradation and to predict the toxicity using a silico toxicity program which confirmed a higher toxicity of all generated by-products.

Occurence of antimicrobial residues in milk and labneh consumed in Lebanon

Antimicrobials are administered in livestock for different uses leading to milk contamination and several undesirable effects. Because there is a lack of surveillance of antimicrobial residues (AMRs) in milk and dairy products in Lebanon, this study aims to determine the occurrence of AMRs in 90 Lebanese samples of milk and labneh (concentrated yoghurt). Multi-residue screening methods with suitable sample preparations were applied to detect 71 AMRs in milk and labneh, respectively, using LC-MS/MS. Of the total number of samples, 71% was contaminated with AMRs and (fluoro)quinolones and macrolides were the most detected families. Additional confirmation tests proved that 6.7% of the milk samples were non-compliant for the macrolides tilmicosin, tulathromycin and spiramycin. Moreover, some labneh prepared from contaminated milk samples was analysed to determine the fate of AMRs during the manufacturing process. The results showed that some AMRs could be concentrated, eliminated or degraded, based on their physicochemical characteristics.

Degradation of azoxystrobin, methoxyfenozide, and propyzamide by ultrasound treatment

Ultrasound as a green and efficient process gains special attention in wastewater treatment. The ultrasound-assisted degradation of azoxystrobin, methoxyfenozide, and propyzamide as widely used pesticides for vine treatment was investigated. A wide range of ultrasonic power (40 to 140 W) and a single frequency (20 kHz) were applied. Degradation experiments were carried out according to the parameters set by a central composite design (CCD) under response surface methodology (RSM) via JMP software. The treatment efficiency was quantified using degradation rates and hydrogen peroxide (H2O2) measurements. Results indicated that the pesticide's degradation was negligible at 40 W but by increasing the power setting from 80 to 140 W, the degradation rate constants of azoxystrobin, methoxyfenozide, and propyzamide increased from 3.6 × 10-2 min-1 to 0.2 min-1, from 6.1 × 10-2 min-1 to 0.3 min-1, and from 3.1 × 10-2 min-1 to 0.1 min-1, respectively. The hydrogen peroxide (H2O2) measurements confirmed this trend. Besides, electric energy per order of pollutant removal (EE/O) was also evaluated for the same treatment duration and results revealed that treatment conditions of 20 kHz and 140 W were the less energy-guzzling. Finally, profiles obtained with RSM illustrated linear degradation kinetics for azoxystrobin and propyzamide. Indeed, treatment efficiency increased when increasing both studied parameters. However, both linear and quadratic degradation kinetics occurred for methoxyfenozide degradation indicating a parameter threshold beyond which the trend is reversed. Overall, this study confirms the effectiveness of ultrasound for the degradation of pesticides in aqueous medium.

Is There Correlation Between Aluminum-Based Food Consumption and Plasma Level in Pregnant Women?

To explore the correlation of AL-based food consumption, known to have negative impact on health, and Al plasma levels with pregnancy status. A cross-sectional study was conducted on 75 participants, including 50 pregnant women. Al plasma levels were analyzed by ET-AAS. Exposure to food was positively correlated to Al mean plasma levels (reaching 2.12 ± 1.17 μg/L) by 32%, specifically for potatoes, fruits, soft drinks, and ready meals. Usage of Al cookware was associated to higher Al plasma levels while pregnancy status was protective. Establishment of national recommendation to maintain lower levels of Al in food is required.

Chromatographic methods for the determination of a broad spectrum of UV filters in swimming pool water

This paper describes an analytical approach based on solid-phase extraction (SPE) followed by analysis using liquid and gas chromatography coupled to mass spectrometry detectors for a determination of 18 organic UV filters from water samples. Extraction method parameters were optimized: 250 ml of water sample loaded on Chromabond C18 cartridges after adjustment to pH 4 and then eluted with acetonitrile. The mobile phase and the parameters of the mass spectrometer, as well as those of the ionization source, were tested to enhance detection sensitivity. During method validation, the extracted target compounds showed good recoveries (> 68%) with acceptable values in terms of repeatability (RSD_r) and reproducibility (RSD_R), where relative standard deviations values were lower than 20%. The validated method was applied to 10 water samples collected from different swimming pools located in Lebanon from which eight UV filters among the eighteen targets compounds were detected at concentrations ranged between 1 and 2526 µg L^-1. The most detected compounds were padimate-O (OD-PABA) and octocrylene (OCR). This study represents the first available data on the occurrence of UV filter residues in Lebanese swimming pool opening hence future perspectives and insights to evaluate their degradation by-products and their toxicity on human health and marine ecosystem.

Evaluation of honey authenticity in Lebanon by analysis of carbon stable isotope ratio using elemental analyzer and liquid chromatography coupled to isotope ratio mass spectrometry

Honey is one of the most valuable sweeteners consumed by humans all over the world. Consequently, it is often a target for adulteration through the addition of different sugar syrups during or after honey production, resulting in a reduction in its nutritive value. For the first time, this study analyzes honey samples of various botanical species collected from different Lebanese regions using element analyzer (EA) and liquid chromatography (LC) coupled with isotope ratio mass spectrometry (IRMS). The δ13 C of bulk honey, its protein fraction, and the main individual sugars (glucose, fructose, disaccharides, and trisaccharide) were determined, in order to characterize and evaluate the authenticity of honey consumed in Lebanon. The results showed that the δ13 C values for bulk honey and its protein range from -26.5‰ to -24.5‰ and from -26.4‰ to -24.7‰, respectively, for authentic samples. δ13 C values for samples adulterated with sugar syrups range from -11.2‰ to -25.1‰ for bulk honey and from -26.6‰ to -23.7‰ for its proteins, with a difference between bulk and protein values between -1 and -8.7‰. Using LC-C-IRMS techniques, the δ13 C of individual sugars provides additional information on the presence of undeclared sugars. We found that all authentic samples had Δδ13 Cf-g and Δδ13 C max values within the naturally occurring range of ±1‰ and ±2.1‰, respectively, while the adulterated samples fall outside the Δδ13 C ranges. The oligosaccharide peak was detected in most adulterated samples.

Nutritional value of the Middle Eastern diet: analysis of total sugar, salt, and iron in Lebanese traditional dishes

Background: The expanding burden of diet-related non-communicable diseases in the Eastern Mediterranean Countries requires urgent public health vigilance and actions. This study aimed at establishing a database analysis of total sugar, salt and iron content in Lebanese foods, focusing on traditional dishes.

Methods: The collection of food samples was done using stratified sampling techniques. These samples were classified into five strata, taking into account variation by geographical area (Mount Lebanon, Bekaa, Beirut, Tripoli, and Saida). The number of samples per governorate was estimated to be 30 according to the variability in the dishes' composition. Food samples were chemically analyzed for total sugar, salt, and iron.

Results: Among all the governorates, all the tested traditional Lebanese dishes contained little total sugar. More than 60% of the samples tested were rich in sodium. The sodium content ranges were 120-720 mg/100 g in Mount Lebanon, 240-960 mg/100 g in Bekaa, 80-520 mg/100g in Beirut, 252-1952 mg/100g in Tripoli and 40-680 mg/100 g in Saida. The highest mean amount of sodium was observed in the dishes Fatayer Sabanikh and Malfouf Mehche (≥ 600 mg/100 g). Furthermore, more than 80% of the samples had poor amounts of iron in all governorates.

Conclusion: This study emphasizes the need for multi-cultural education and awareness on food sources of salt and iron, and the health effects regarding high intake of salt and low intake of iron. This study is a stepping stone for further research exploring total sugar, salt and iron content of traditional dishes, as well as potential intake by individuals in the Lebanese population.

Aluminum exposure from food in the population of Lebanon

Widely used for a variety of applications, levels of dietary aluminum (Al) have seen a perpetual rise in Lebanon, leading to noticeable effects upon the human body. This study aims to estimate the rates of Al contaminated food consumption and quantify the Al present in different dietary matrices, revealing the major contributors to Al exposure for the Lebanese population. A cross-sectional study was conducted using a customized, self-reported Electronic Food Frequency Questionnaire (E-FFQ) using Curve®, targeting individuals between the ages of 18 and 64 from different Lebanese regions, distributed proportionally. The selection of food was based upon the results of the French EAT2 study. Al levels in food were analyzed using Flame Atomic Absorption Spectrometry (FAAS) after acid digestion. The E-FFQ was completed by 167 respondents. Data analysis was performed on SPSS version 25. Additionally, 97 food items were studied in 2018. Al levels had a mean of 3.56 ± 2.08 mg/kg (ranging from 0.14 to 9.37). The highest Al levels were found in vegetables, followed by sauces and condiments, candies, and ready meals. The Provisional Tolerable Weekly Intake (PTWI) of Al was set at 0.50 mg/kg body weight (60 Kg/person). Al mean Daily Dietary Exposure (DDE) was estimated to be 4341.18 μg/day, with the highest food exposure coming from lettuce, soft drinks, ice cream and tea. Al ingestion rates for the adult Lebanese population does not exceed the international established thresholds of tolerable intake (1 mg/kg/week). National recommendation should be developed to control the presence of metal for food safety purposes.

Antimicrobial residues survey by LC-MS in food-producing animals in Lebanon

The treatment of animals with antimicrobial products may lead to the contamination of edible tissues by their residues, which may represent a risk to human health. Therefore, this study aimed to determine the level of antimicrobial residues in food-producing animals (chicken, beef, and milk) in Lebanon. A total of 310 samples were collected and analysed using an LC-MS/MS for the determination of 48 compounds belonging to different families in order to map their compliance according to the European Commission decision 2002/657/EC. Results show that 60% of the analysed samples were not contaminated by any residue, while 12% presented a concentration higher than the MRLs for tetracyclines, sulphonamides, quinolones, and macrolides. Results revealed that chicken were the most contaminated by antimicrobial residues, when compared to beef and milk. The obtained results demonstrate the uncontrolled use of antimicrobials in some Lebanese farms and claim for better management of livestock.

LC-MS/MS method for the determination of hormones: Validation, application and health risk assessment in various bovine matrices

A new method, using liquid chromatography coupled to mass spectrometry (LC-MS/MS) for the detection of fourteen natural and synthetic hormones in muscles, was validated in other bovine matrices (liver, kidney, bile and hair) according to the Decision Commission 2002/657/EC. As result, this method demonstrates good linearity (R² > 0.99) as well as accuracy with coefficients of variation for repeatability and reproducibility lower than 23%. Moreover, the values of decision limit (CCα) and detection capability (CCβ) were determined indicating values ranging from 0.13 to 0.86 μg/kg and 0.25-1.72 μg/k for the majority of analytes. Recovery rate in the different matrices varied from 51.5 to 107%. Indeed, this method has been successfully applied to detect anabolic hormones in eighty-eight samples (muscle, liver, kidney, and bile) collected from different local slaughterhouses. Results showed that progesterone was found in 30 samples at concentrations ranging from 0.11 to 11.7 μg/kg, while testosterone was detected in 34 samples at concentrations ranging from 0.5 to 9.52 μg/kg. All bile samples contain epi-testosterone at concentration ranging from 0.89 to 280 μg/kg. These obtained data were used to calculate the estimated daily intake, hazard quotient and hazard index as exposure assessment.

Transformation of sulfaquinoxaline by chlorine and UV light in water: kinetics and by-product identification

Sulfaquinoxaline (SQX) is an antimicrobial of the sulfonamide class, frequently detected at low levels in drinking and surface water as organic micropollutant. The main goal of the present study is the evaluation of SQX reactivity during chlorination and UV irradiations which are two processes mainly used in water treatment plants. The SQX transformation by chlorination and UV lights (254 nm) was investigated in purified water at common conditions used for water disinfection (pH = 7.2, temperature = 25 °C, [chlorine] = 3 mg L^-1). The result shows a slow degradation of SQX during photolysis compared with chlorination process. Kinetic studies that fitted a fluence-based first-order kinetic model were used to determine the kinetic constants of SQX degradation; they were equal to 0.7 × 10^-4 and 0.7 × 10^-2 s^-1corresponding to the half time lives of 162 and 1.64 min during photolysis and chlorination, respectively. In the second step, seven by-products were generated during a chlorination and photo-transformation of SQX and identified using liquid chromatography with electrospray ionization and tandem mass spectrometry (MS-MS). SO₂ extrusion and direct decomposition were the common degradation pathway during photolysis and chlorination. Hydroxylation and isomerization were observed during photodegradation only while electrophilic substitution was observed during chlorination process.

Photodegradation of novel oral anticoagulants under sunlight irradiation in aqueous matrices

Kinetics of photodegradation of novel oral anticoagulants dabigatran, rivaroxaban, and apixaban were studied under simulated solar light irradiation in purified, mineral, and river waters. Dabigatran and rivaroxaban underwent direct photolysis with polychromatic quantum yields of 2.2 × 10^-4 and 4.4 × 10^-2, respectively. The direct photodegradation of apixaban was not observed after 19 h of irradiation. Kinetics of degradation of rivaroxaban was not impacted by the nature of the aqueous matrix while photosensitization from nitrate ions was observed for dabigatran and apixaban dissolved in a mineral water. The photosensitized reactions were limited in the tested river water (Isle River, Périgueux, France) certainly due to the hydroxyl radical scavenging effect of the dissolved organic matter. The study of photoproduct structures allowed to identify two compounds for dabigatran. One of them is the 4-aminobenzamidine while the second one is a cyclization product. In the case of rivaroxaban, as studied by very high field NMR, only one photoproduct was observed i.e. a photoisomer. Finally, seven photoproducts were clearly identified from the degradation of apixaban under simulated solar light.

Innovative SPE-LC-MS/MS technique for the assessment of 63 pharmaceuticals and the detection of antibiotic-resistant-bacteria: A case study natural water sources in Lebanon

A powerful analytical method for simultaneous determination of 63 pharmaceuticals and some metabolites in aqueous samples has been developed. The list of compounds amenable to the methods includes different therapeutic classes belonging to antibiotics, stimulants, antidepressants, mucolytics, and antiparasites. The method involves concentration and clean up by an offline solid phase extraction SPE followed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS/MS). The recovery of the target compounds from water samples was most efficient on Waters Oasis HLB SPE cartridge, while acetonitrile/water (60/40) was shown to be the most suitable solvent for desorbing the compounds from SPE. In addition, acidification of samples prior to SPE was optimized to enhance the recovery of the compounds. In terms of method validation, the recoveries of analytes ranged from 68% to 134%. Repeatability and intermediate precision were <11% and 14%, respectively. The method detection limits ranged from 2.3ngL^-1 to 94.3ngL^-1. An optimized method was applied in a monitoring program to study the occurrence of pharmaceuticals to more than hundred samples collected from rivers, lakes, fountains, and wells overall Lebanon from April to June 2016. Caffeine, erythromycin and its degradation forms, were the most frequently detected compounds at levels reaching >10,000ngL^-1 and 2000ngL^-1, respectively. Moreover, bacterial analysis showed that the samples were contaminated by Escherichia coli (23%), intestinal Enterococcus (48%) and Pseudomonas aeruginosa (27%). Therefore, in order to evaluate if a correlation exists between finding antibiotics in water samples and the development of resistant-bacteria, an antimicrobial susceptibility test was conducted to the identified isolates using disk diffusion method. Multiple-antibiotic-resistant strains in both intestinal Enterococcus and E. coli were evident in many water samples, while P. aeruginosa was resistant to only one studied antibiotic.

Design for the transfer of a validated liquid chromatography/tandem mass spectrometry analytical method for the determination of antimicrobial residues in honey from low-resolution to high-resolution mass spectrometry

RATIONALE

This paper investigates the validity of the transfer of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of veterinary medicinal products in honey and compares it with an LC/linear ion trap/Orbitrap mass spectrometry method. A descriptive statistical approach was used in order to assess whether such a transfer would succeed or fail. This approach is based on the simultaneous evaluation of the trueness and of the intermediate precision for each compound at a 95% interval of confidence of both analytical techniques.

METHODS

Two grams of honey were placed in a centrifuge tube and diluted with 2.5 mL of ultra-pure water and 2.5 mL of acidified methanol with hydrochloric acid at 2 mol.mL^-1 . The extract was purified with 50 mg of primary secondary amine and then analyzed using LC/MS/MS in multiple reaction monitoring (MRM) mode and LC/orbitrap high-resolution mass spectrometry in full scan mode. Both analytical techniques were compared by using the descriptive statistical approach for the determination of antimicrobial residues in honey.

RESULTS

The transfer of the method showed that the Orbitrap system provides the same accurate analytical results compared with the LC/MS/MS method except for 4-epitetracycline, anhydroerythromycin A, erythromycin A enol ether, and dihydrostreptomycin. Furthermore, the LC/LTQ-Orbitrap system is capable of successfully competing with the LC/MS/MS method by additional provision of high mass resolution and mass accuracy even though it shows less sensitivity compared with the LC/MS/MS instrument. CCα levels for most analytes were 1.3 times higher by LC/MS/MS than those observed by LC/LTQ-Orbitrap. The method was assessed in terms of relative bias through analysis of a reference material provided by FAPAS (Food Analysis Performance and Assessment Scheme) and also through the control of several contaminated honey samples from local Lebanese markets. Satisfactory relative bias was below 22% except for tetracycline found in one sample that showed a higher bias at 29%.

CONCLUSIONS

The LC/LTQ-Orbitrap method offers adequate performance in comparison with previously validated method on a LC/MS/MS system resulting in acceptance of the transfer of the method from LC/MS/MS to LC/LTQ-Orbitrap. Copyright © 2017 John Wiley & Sons, Ltd.

Oxidation of danofloxacin by free chlorine-kinetic study, structural identification of by-products by LC-MS/MS and potential toxicity of by-products using in silico test

In this study, we aimed to investigate the kinetics and the mechanism of reaction of the fluoroquinolone antibacterial danofloxacin (DANO) by free available chlorine (FAC) during water chlorination process. Kinetic study was thus performed at pH 7.2, 20 °C in the presence of an excess of total chlorine. Under these experimental conditions, a second-order reaction rate constant (first-order relative to DANO concentration and first-order relative to FAC concentration) was evaluated to k~1446 M^-1 s^-1. Five degradation products were identified at different reaction times. Their structures were investigated by using fragmentations obtained at different CID collision energies in MS/MS experiments. Moreover, the toxicity of the proposed structures was predicted by using T.E.S.T.

PROGRAM

The results indicated that all by-products may have a developmental toxicity. The oral rat LD₅₀ concentration was predicted to be lower than that of DANO. Furthermore, two degradation compounds presented a concentration level for fathead minnow LC₅₀ (96 h) lower than that of DANO and presented toxicity for the marine animals.

Occurrence of pesticide residues in Lebanon's water resources

Contamination of water sources by pesticides is one of the most critical environmental problems. The present work is designed to address the occurrence of 67 pesticides in the Lebanese waters. Chemical analysis was performed by a solid-phase extraction followed by a gas chromatography-mass spectrometry using programmed temperature vaporization injection. In drinking water and groundwater samples, organochlorine and organophosphate pesticides were frequently detected with a maximal sum concentration of up to 31.8 ng L(-1). High pesticide ecotoxicological risk was noticed in many surface waters, while this risk was driven mainly by diazinon, chlorpyrifos, fenpropathrin and bifenthrin insecticides.

Optimization of a solid-phase extraction method using centrifugation for the determination of 16 polycyclic aromatic hydrocarbons in water

A fast and reliable method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by solid-phase extraction (SPE) using centrifugation has been developed and optimized. A silica-based C18 cartridge was used; parameters affecting the extraction procedure such as type and volume of the elution solvent, breakthrough volume of the percolated water sample, drying of the sorbent, and evaporation of the elute have been studied. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 1 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under optimal conditions, recoveries for the 16 U.S. EPA PAHs were between 70 and 85% and the relative standard deviation varied between 1 and 14%. Surrogate standard recoveries were similarly between 61 and 94% with a relative standard deviation between 2 and 15%. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.