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Removal of residual pesticides on vegetable using ozonated water
Abstract
Degradation of the four pesticides by dissolved ozone was investigated in order to establish the effect of operational parameters: methyl-parathion, parathion, diazinon and cypermethrin. They were commonly used as broad-spectrum insecticides in pest control, and high residual levels had been detected in vegetables. In the present study, the effectiveness in pesticide oxidation in aqueous solution using low level of dissolved ozone was determined using solid-phase micro-extraction (SPME) and GC–MS. Dissolved ozone (1.4 mg/l) was effective to oxidize 60–99% of methyl-parathion, cypermethrin, parathion and diazinon in aqueous solution in 30 min and the degradation was mostly completed in the first 5 min. Trace amounts and unstable paraoxon and diazoxon were tentatively identified as primary ozonation byproducts of parathion and diazinon. The feasibilities of using low level of dissolved ozone (1.4–2.0 mg/l) for removal of the four pesticides residue on vegetable surface (Brassica rapa) were also tested. Ozone was mostly effective in cypermethrin removal (>60%). The removal efficiency of pesticides highly depended on the dissolved ozone levels and temperature. The present study validated that ozonation is a safe and promising process for the removal of the tested pesticides from aqueous solution and vegetable surface under domestic conditions.
... For this reason, many distribution chains and food industries require growers to reduce residue levels to an even greater extent. Therefore, in addition to controlling PPPs' preharvest interval time in the field, effective ways are being considered to preventively remove pesticide residues already present on vegetables to avoid adverse effects on human's health [5]. ...
... A potential health risk could be linked to pesticide degradation byproducts caused by ozonated water treatments given that they may be more toxic than the pesticides themselves. In this regard, earlier studies have already indicated that only traces of unstable degradation byproducts could be found and that no bioaccumulation and toxicity were detected when ozone was used to degrade pesticides [5,29]. However, further research should be undertaken to investigate the toxicity of byproducts resulting from the ozonated water treatment of the tested pesticides. ...
... Moreover, it may be useful to continue to apply ozone to waste water after the described treatments in order to remove pesticide residues in it. Reports on the degradation of pesticides in water using ozone or other oxidants are available [5,30,31], so it is expected that continuous ozone treatment may be able to break down the molecules accumulated in waste water, thus solving the issue of waste water disposal. ...
Nowadays, different systems for reducing pesticides in table grapes are being tested at different production stages either in the field or in postharvest. The present study tested ozonated water treatments at the beginning of the cold storage of the Princess® seedless table grape variety to reduce the residue contents of some pesticides and to evaluate their effect on gray mold and the berry microbiome. An ozone generator capable of producing an ozone concentration ranging from 18 to 65 Nm³ was utilized for obtaining three ozone concentration levels in water: 3, 5 and 10 mg/L. Ozonated water was placed in a 70 L plastic box where 500 g grape samples closed in perforated plastic clamshell containers were immersed utilizing two washing times (5 and 10 min). Overall, six ozonated water treatments were tested. After the ozonated water treatments, all samples were stored for 30 days at 2 °C and 95% relative humidity to simulate commercial practices. The pesticide residue contents were determined before the ozonated water treatments (T0) and 30 days after the cold storage (T1). The treatments with ozonated water washing reduced the pesticide residues up to 100%, while the SO2 control treatment reduced the pesticide residues ranging from 20.7 to 60.7%. Using 3 mg/L ozonated water to wash grapes for 5 min represented the optimal degradation conditions for all of the analyzed pesticides, except for fludioxonil, which degraded better with a washing time of 10 min. The ozone treatments did not significantly reduce the gray mold and the fungal and bacterial microbiome, while a relevant reduction was observed in the yeast population.
... Impacts of ozonated water on parathion, diazinon, cypermethrin, and methyl parathion in vegetables under watery conditions were researched in two distinct techniques: in a first strategy, 1 ml of 10 mg L -1 pesticide arrangement was blended in with an over the top portion of ozone (99 ml of 1.4 mg L -1 ozonated water) while in the second technique pesticide spiked vegetables were dealt with ozonated water for different conditions. Excluding methyl-parathion, over 75% of all the pesticides were degraded upon ozone treatment for 10 min [32]. Ikeura H, et al. [33] accentuated that the lower corruption pace of fenitrothion deposits in cherry tomatoes contrasted with strawberries was expected with the lower surface zone of the previous contrasted with the last mentioned. ...
... Likewise, the solvency of ozone increments with an expansion in virtue of water, in light of the fact that the nearness of natural issue and minerals catalyze the disintegration of ozone in water [70]. Wu J, et al. [32] treated vegetables with low centralization of ozonated water to evacuate the buildups of diazinon, parathion, and methyl-parathion and cypermethrin. Despite the fact that the capacity to evacuate pesticides relies to a great extent upon ozone fixation, the high temperature conditions likewise improve its viability. ...
... However, with the development of optimized process conditions for each fruit and vegetable, these negative effects could be greatly reduced. Also, the available literature states that the ozone treatment yields some degradation products of pesticide residues that were found to be more toxic than the parent compounds [119,32]. ...
... However, a relationship between the structural properties of the matrices and the removal of pesticides was not be established though ozone is found to effective in removing all three pesticide residues in both peeled and unpeeled matrices. Contrarily, findings by Wu, Luan, Lan, Lo, and Chan (2007) reveal the dosage of ozone does not exert any effect on pesticide removal while increasing temperature also showed negative effects. These differences in the efficacy of ozone treatment can be attributed to the different physico-chemical properties of the food matrices and pesticides used in these investigations. ...
... Effects of ozonated water on parathion, diazinon, cypermethrin, and methyl-parathion in vegetables under aqueous conditions were investigated in two different methodologies (Wu et al., 2007). In a method, 1 ml of 10 mg L −1 pesticide solution was mixed with an excessive dose of ozone (99 ml of 1.4 mg L −1 ozonated water) while in the second method pesticide spiked vegetables were treated with ozonated water for different conditions. ...
... Also, the solubility of ozone increases with an increase in purity of water, because the presence of organic matter and minerals catalyze the decomposition of ozone in water (Miller et al., 2013). Wu et al. (2007) treated vegetables with low concentration of ozonated water to remove the residues of diazinon, parathion, and methyl-parathion and cypermethrin. Even though the ability to remove pesticides depends largely on ozone concentration, the high temperature conditions also enhance its effectiveness. ...
... However, a relationship between the structural properties of the matrices and the removal of pesticides was not be established though ozone is found to effective in removing all three pesticide residues in both peeled and unpeeled matrices. Contrarily, findings by Wu, Luan, Lan, Lo, and Chan (2007) reveal the dosage of ozone does not exert any effect on pesticide removal while increasing temperature also showed negative effects. These differences in the efficacy of ozone treatment can be attributed to the different physico-chemical properties of the food matrices and pesticides used in these investigations. ...
... Effects of ozonated water on parathion, diazinon, cypermethrin, and methyl-parathion in vegetables under aqueous conditions were investigated in two different methodologies (Wu et al., 2007). In a method, 1 ml of 10 mg L −1 pesticide solution was mixed with an excessive dose of ozone (99 ml of 1.4 mg L −1 ozonated water) while in the second method pesticide spiked vegetables were treated with ozonated water for different conditions. ...
... Also, the solubility of ozone increases with an increase in purity of water, because the presence of organic matter and minerals catalyze the decomposition of ozone in water (Miller et al., 2013). Wu et al. (2007) treated vegetables with low concentration of ozonated water to remove the residues of diazinon, parathion, and methyl-parathion and cypermethrin. Even though the ability to remove pesticides depends largely on ozone concentration, the high temperature conditions also enhance its effectiveness. ...
Consumption of fruits and vegetables is an indispensable component of human dietary preference, however; it is unfortunate that the enormous pesticide residues remain in the plant produces. Pesticides used to control the pests and diseases of the crops and livestock and its spill-over in the food production system has been an inevitable consequence. Researchers have been taking persistent efforts to eliminate pesticide
residues in the food to make it safe for human consumption. Conventional techniques
such as the washing of agricultural produces with chemicals, peeling, salting, and using different agents have not been an efficient means of pesticide removal.
Scope and approach: In recent times, the emergence of non-thermal technology such as the ozone to degrade the pesticide residues is of great utility in the food processing
industries. It is also considered as a green technology because unlike other conventional methods ozone treatment leaves little residual traces. However, some of the discrepancies and challenges in using this technology require to be addressed to increase its efficiency. The objective of the current review is to provide a comprehensive and critical view of the use of ozone in pesticide residue dissipation in various food matrixes. Key findings and conclusion: Analysis of the pros and cons of ozone treatment reveals it as a potential technique for the degradation of pesticide residues. The diversity and complexity of pesticides along with the inherent differences in their chemical structures and residue levels of pesticides in agro-products are the factors that require due
consideration. Furthermore, processing and operating conditions of the ozone treatment are some of the other major determinants to improve the efficiency of ozone treatment for the degradation of pesticides
... For this reason, many distribution chains and food industries require growers to reduce residue levels to an even greater extent. Therefore, in addition to controlling the PPPs' pre-harvest interval time in the field, effective ways are being considered to preventively remove pesticide residues already present on vegetables to avoid adverse effects on human's health [5]. One of the latest methods involves the generation of ozone gas in water as a washing treatment to reduce pesticide residues in fruits and vegetables [6][7][8][9]. ...
... A potential health risk could be linked to pesticide degradation byproducts caused by ozonated water treatments given that they may be more toxic than the pesticides themselves. In this regard, earlier studies have already indicated that just a trace of unstable degradation byproducts could be found and that no bioaccumulation and toxicity were detected when ozone was used to degrade pesticides [5,15]. However, further research should be undertaken to investigate the toxicity of by-products resulting from ozonated water treatment of the tested pesticides. ...
Nowadays, different systems for reducing pesticides in table grapes are being tested at different production stages either in the field or in post-harvest. The present study tested ozonated water treatments at the beginning of the cold storage on Melissa seedless table grape variety to reduce residue contents of some pesticides. An ozone generator capable of producing ozone concentrations ranging from 18 to 65 Nm ³ was utilized for obtaining three ozone concentration levels in water: 3, 5 and 10 mg/L. Ozonated water was placed into a 70 L plastic box where 500 g grape samples closed in perforated plastic clamshell containers were immersed utilizing two washing times (5 and 10 min). Overall, six ozonated water treatments were tested. After ozonated water treatments, all samples were stored for 30 days at 2 °C and 95% relative humidity to simulate commercial practice. Pesticide residue contents were determined before ozonated water treatments (T 0 ) and 30 days after the cold storage (T 1 ). The comparison highlighted the different degradation rates as regards Fludioxonil and Fluxapyroxad. The best results were reached among the non-systemic pesticide such as Fludioxonil. Using 3 mg/L ozonated water to wash grapes for 10 min represented the optimal degradation conditions for the analyzed pesticides.
... Similarly, some pesticides such as malathion, diazinon, atrazine, bromoxynil and trifluralin were oxidized by ozone for decomposition or degradation in aqueous solution (Ku et al. 1998;Ma and Graham 2000;Masten et al. 2001). Furthermore, it was reported that some residual pesticides on the surface of fruit and vegetables were degraded by ozone treatment (Ong et al. 1996;Hwang et al. 2001;Wu et al. 2007;Kuşvuran et al. 2012). In these studies, pesticide residues were removed (changing levels between 46.0 and 98.6%) from produce depending on atmosphere temperature, application dose, type and duration. ...
... ppm dissolved ozone. Similarly, it was indicated that the removal pesticides from horticultural produce was achieved meaningfully with dipping in water containing dissolved ozone (Wu et al. 2007; Mean ± standard deviation (n = 10); RSD r = Repeatability; RSD wR = Within-laboratory reproducibility J Food Sci Technol Kuşvuran et al. 2012;Khaled et al. 2017). In the present study, the removal percentage of acetamiprid was remarkable lower than malathion and emamectin benzoate in peppers dipped in ozonated water. ...
The use of ozone as a tool in the storage of some horticultural produces is recommended for all steps from harvest to consumption. However, little is known about its effects on the removal of pesticides and postharvest physiology of fresh peppers. In the present study, the effects of ozone treatment on the removal of pesticides, storage life and quality of green peppers were investigated. Malathion, emamectin benzoate and acetamiprid were applied to pepper plants before harvest. Residue contents of peppers were measured at harvest time and after all treatments to determine the effect of ozone on the removal of pesticide residues. Peppers were subjected to four treatments: immersion in ozonated water (2 ppm) and only tap water (control) for 10 min, exposure to 2 ppm ozone gas in air and only air (control) for 45 min. Treated peppers were stored at 20 °C and 60 ± 5% relative humidity for 8 days, and some quality analyses were performed during storage. Ozonated water decreased, remarkable, pesticide residues in peppers compared to harvest time, but there was no meaningful changes in the samples treated with ozone in air. Ozone treatments suppressed clearly respiration rates and decreased weight losses of peppers compared to control groups. Ozonated water also maintained green color of peppers, with minimum change in h° values. Additionally, sensory quality of peppers was retarded by ozone application during storage. These findings revealed that ozone could be an alternative treatment to extend storage life of green peppers and remove pesticide residues.
... Washing not only addresses surface pesticides but also those embedded within the food products (Li et al., 2015). The removal of pesticides during washing can occur through dissolution in the washing water or rinsing with various chemical baths (such as alkaline, acid, hydrogen peroxide, electrolyzed water, and ozonated water) as shown by multiple studies (Calvo et al., 2019a, b;Kim et al., 2016;Ong et al., 1996;Pugliese et al., 2004;Wu et al., 2007Wu et al., , 2019Zohair, 2001). Additionally, the removal of dust or soil particles that absorbed residues from the outer layer of fruits and vegetables is another aspect of effective washing (Hordyjewicz-Baran et al., 2024). ...
Pesticides play a crucial role in enhancing crop productivity in agriculture. However, the residues of these pesticides can remain in food materials after harvest, impacting human health, and becoming a significant obstacle in international food trade. The presence and concentration of pesticide residues vary based on factors such as the type of pesticide, the nature of the food, and environmental conditions. In recent years, various processing techniques have emerged as effective tools for reducing or eliminating pesticide residues from food, thereby enhancing food safety. Effective methods include washing with water, soaking in solutions containing substances like chlorine, hydrogen peroxide, or ozone, as well as peeling and trimming the outer portions. Thermal processing techniques such as pasteurization, boiling, and cooking can also degrade pesticides, while preservation methods like drying can increase pesticide content due to concentration effects. Additionally, various instrumental processing techniques, such as UV ultrasound and microwaves, can influence pesticide levels in foods to varying degrees. Many of these decontamination methods can reduce pesticide concentrations below Maximum Residue Limits (MRLs), but their effectiveness depends on factors such as initial pesticide concentration, the type of food, and the specific pesticide used. This chapter compiles a wide range of information from the literature, covering the impact of preparation, processing, handling, and storage on pesticide residues in foods. Additionally, it explores the significance of these processing techniques in remediating pesticide residues, providing insights into their mechanisms, applications, and prospects.
... The acute and chronic risk index values showed that there was no health risk for consumers of Cumilla, Bangladesh, due to intake of organophosphorus pesticide residues on these vegetables. Pesticide concentrations in vegetable products are known to be reduced by different home processing like washing, peeling, or cooking (Soliman,2001;Wu et al., 2007;Ling et al., 2011;Yang et al., 2012;Huan et al., 2015). So, future studies should consider processing factors to compensate for reducing or removing pesticides. ...
Main theme of the current issue is-Plastic Pollution and Other Health Hazards
... Ozone gas eliminates pathogen spores, thereby reducing the microbial population [28,33]. Additionally, it is used to reduce the burden of mycotoxins and pesticide residues [34,35]. The exposure of plants and harvested fruits and vegetables to O 3 during vegetation causes metabolic changes. ...
The aim of this research was to determine the impact of hydrogen peroxide spraying and ozone gas fumigation during the growing season of tomato plants grown under cover on the mechanical and chemical parameters of fruit harvested from these plants. Tomato plants were grown under cover in accordance with the principles of good agricultural practice in the soil and climatic conditions of southeastern Poland. During the growing season, tomato fruits were collected for testing in order to determine the impact of the applied variable factors on the modification of selected metabolic pathways of bioactive compounds. As part of the tests on the chemical properties of the fruits, the content of ascorbic acid, the total content of polyphenols, and the antioxidant potential were determined. Additionally, the influence of the tested variable factors on the mechanical properties of tomato fruits was determined. In the case of the total polyphenol content, the most beneficial effects were observed for fruits collected from plants treated with ozonation at a dose of 2 ppm for 3 min and spraying the plants with 1% hydrogen peroxide. The highest antioxidant potential was recorded for fruits of the variants ozonated with doses of 2 ppm for 1 min, 2 ppm for 1.5 min, and 2 ppm for 3 min compared to the remaining variants and controls. In turn, the vitamin C content increased significantly in the tested fruits after the ozonation of plants with a dose of 2 ppm for 1 min and ozonation with a dose of 2 ppm for 3 min combined with spraying plants with 3% hydrogen peroxide. In the case of the mechanical properties of tomato fruits, only the ozonation dose of 2 ppm for 3 min significantly improved them.
... Table 5.2 shows the application of OW and its subsequent changes in food commodities (Premjit et al., 2022). Wu et al. (2007) studied the effect of ozonated water on the removal of four pesticides in water and on the surface of the vegetable -Brassica rapa (Pak Choi). It was observed that 1.4 mg/L and 2 mg/L (Ali et al., 2021) * is provided to indicate the b value representing CIELAB color scale of ozone for 30 mins reduced the levels of diazinon, parathion, methyl parathion, and cypermethrin with the generation of some by-products such as paraoxon, diazaxon, oxons, methyl paraoxon, etc. Temperature also influences its activity, where treatment done at 14°C was better than treatment done at 24°C. ...
... Another study examined the use of low levels of dissolved ozone (1.4-2.0 mg/L) to eliminate residues of four pesticides (methyl-parathion, parathion, diazinon and cypermethrin) on Brassica rapa vegetable surfaces. Notably, ozone exhibited considerable effectiveness in removing cypermethrin, with removal rates exceeding 60% [37]. Furthermore, the efficiency of pesticide removal was found to be closely linked to the levels of dissolved ozone and temperature. ...
Grape seeds, a valuable by-product of winemaking, are rich in bioactive compounds with significant economic potential. However, pesticide residues in grape seeds pose risks to human health and product quality. This study explores innovative technologies including cold plasma, ultrasound, aqueous ozone, and gaseous ozone to eliminate pesticide residues from grape seeds. Cold plasma treatment emerged as highly effective, completely eliminating certain pesticides like Triadimenol and Azoxystrobin. Ultrasound treatment also showed promising results, particularly in reducing Pyrimethanil residues. Aqueous ozone treatment achieved moderate reductions, while gaseous ozone exhibited the least efficacy. Factors influencing efficacy included pesticide type, treatment duration, and matrix characteristics. Future research should focus on optimizing parameters to enhance pesticide removal while minimizing impacts on product quality. These findings underscore the importance of tailored approaches for pesticide elimination, contributing to safer agricultural practices and consumer health
... Processing such as peeling, soaking in chemical baths and blanching can reduce pesticide residues more effectively than washing and soaking (Chung 2018). Ozonation is a safe and promising process for the removal of the tested pesticides from aqueous solution and vegetable surfaces under domestic conditions (Wu et al., 2007). Reduction of pesticide residue levels was indicated by blanching, boiling, canning, frying, juicing, peeling and washing fruits and vegetables with an average response ratio ranging from 0.10 to 0.82. ...
... 16 It may lead to an additional shift in the conduction band, which can go below the redox potential. 17,18 The inorganic Ag material has nontoxicity, outstanding biocompatibility, chemical reactivity, excellent antimicrobial activity, and high thermal stability because of the generation of reactive O 2 spices and release Ag ion at the external area of nanomaterials. It is predicted that the doping of Ag may be affected by the physiochemical properties of nanomaterials. ...
Herein, inexpensive and eco‐friendly approach for the green synthesis of silver‐doped metal hexacyanoferrates (Ag@MHCFs) nanocomposite using green tea extract has been reported. Silver‐doped MHCF nanocatalysts were used to photo‐degradation endocrine disruptor pesticides, namely endosulfan (ES) and atrazine (AT), from water under direct Sunlight. Spectroscopic and electron microscopic techniques confirmed the successful synthesis of nanomaterials. Ag@FeHCF observed maximum degradation efficiency due to their high surface area (89.3 m²g⁻¹), significant zeta potential (−43.4 mV), lower band gap (1.5 eV), and low photoluminescence intensity as compared to other Ag doped MHCFs. Best degradation results showed with concentration amount (5 mg L⁻¹), dose (20 mg of ES; 15 mg of AT), at neutral pH under sunlight irradiation. Degradation up to 98% for ES and 96% for AT was reported. The degradation ensued by Langmuir adsorption and first‐order kinetics. GC–MS analysis showed the degradation of pesticides into CO2, H2O, and harmless minor metabolites under Sunlight. Ag@FeHCF have indicated high reusability (n = 10), ensuring their charge separation, stability, and sustainability. Ag@MHCF nanoparticles may show as substitute catalysts for industrial use with a fervent scope.
... Therefore, it must be combined with H 2 O 2 , UV light, catalysts, photocatalysts, or ultrasound to enhance the production of hydroxyl radicals, thereby increasing the treatment efficiency [73]. [60,61] investigated two methodologies: first, a pesticide solution was mixed with an overdose of ozone, and second, pesticide-enriched vegetables were treated with ozonated water under different conditions. More than 75% of all the pesticides were degraded after treatment with ozone for 10 min. ...
The present study reviews the quantitative data on the use of pesticides and their relationship to environmental and human health problems in Brazil. The detection of residual concentrations of pesticides in food and water consumed by humans has raised questions regarding the overuse of pesticides and their consequences. This global concern was registered as the second goal of sustainable development by the United Nations, which refers to sustainable agriculture and alternatives to pesticides. However, besides recognizing the harmful effects of these contaminants on the environment and human health, there is also a need to understand treatment techniques that can remedy the existing conditions and thus alleviate the problems that affect water treatment plants. In this context, this study compiles information pertinent to the use of pesticides and highlights the prospects for the degradation of these persistent pollutants with emphasis on Brazilian data, one of the countries that had the greatest increase in the consumption of pesticides in the world.
... Physical-chemical methods and food processing are two conventional methods that have been used to reduce residual pesticides [12,13]. Physical-chemical methods, such as Fenton oxidation, bio-treatment, or TiO 2 catalytic treatment, have been studied for the removal of pesticides that are soluble in aqueous solutions. ...
In this study, the effect of non-thermal atmospheric plasma (NTAP) treatment on the reduction of residual fludioxonil (C12H6F2N2O2, 4-(2,2-difluoro-1,3-benzodioxol-4-yl)-1H-pyrrole-3-carbonitrile) was investigated through experimental simulation. Fludioxonil is known for its high residual concentration on fruits and vegetables. To simulate residual fludioxonil reduction in the storage location prior to consumption of fruits or vegetables by consumers, we designed an experimental setup utilizing a gas distribution system and a cylindrical dielectric barrier discharge (DBD) plasma source. A cylindrical DBD plasma source was adopted to produce the plasma activated chemical species (O3). To evaluate the effect of plasma treatment on the reduction of residual fludioxonil, experiments were performed under three different conditions: varying concentrations and treatment times of O3, as well as the surface roughness of microscope slide glass. Based on the results, 10 min plasma treatment with an O3 concentration of 11.89 μL/L, which showed a 58.5% reduction rate, is recommended. The O3 concentration has a higher priority than the treatment time for reduction rates of residual fludioxonil.
... Trace amounts of chlorpyrifos (51.11 μg.L − 1 ), dicrotophos (8.76 μg.L − 1 ), and fenitrothion (59.77 μg.L − 1 ) were found in the water that was collected from the wheat farm. Although this water will not be used as drinking water, removing these pesticides from the environment can be very important (Wu et al., 2007). Even though none of the analytes of interest could be found in the tape water. ...
Pesticides are a large group of pristine organic contaminants, which are widely discharged into environmental water due to agricultural activities. Hence, extraction, determination, and removal of pesticides from water resources are necessary for human health. In this study, novel adsorbent was developed based on three-dimensional magnetic graphene coated with gold nanoparticles (3D-MG@AuNPs) for extraction of chlorpyrifos, dicrotophos, fenitrothion, and piperophos as four specific organophosphorus pesticides (OPPs) from wastewater and tap water samples. The proposed nanocomposite was characterized; FTIR and EDX are performed for the expected functional groups and elemental analysis, SEM showed the unique and spherical AuNPs are well dispersed over graphene sheets. In this investigation, the important parameters that have effect on the extraction efficiency, including the desorbing solvent, desorbing solvent volume, vortex time, the extraction time, adsorbent dosage, pH of sample solutions, and salt effect were evaluated. In conclusion, the measured amounts of the chosen OPPs were determined using the gas chromatography microelectron capture (μECD-GC) method. Limits of quantification (S/N ratio of 10) and detection (S/N ratio of 3) were attained at concentrations of 0.26-0.43 μg.L-1 and 0.08-0.14 μg.L-1, respectively. According to the results of the investigations, the synthesized 3D-MG@AuNPs did not require any complicated sample preparation methods; therefore, it is a very good choice for solid magnetic phase extraction studies.
... A previous study reported that PYRs are able to penetrate the crop matrix and possibly get converted to toxic oxidation and hydrolysis products for human intake (Wu et al., 2007). Esterase provides a promising way to solve such a potential problem brought by the residual PYRs on crops, which can be attributed to the fact that pyrethroids are the ester-containing compounds whose main degradation route involves cleavage of the ester bond (Sogorb and Vilanova, 2002). ...
Esterase, as a type of powerful catabolic enzyme for the degradation of pyrethroid pesticides (PYRs), appears promising in improving the quality of crops and the environment contaminated by pesticide residues. The purpose of this research is to provide a detailed introduction to the enzymatic properties, optimal production and immobilization conditions, and the degradation ability of Est804 for PYRs. The study on enzymatic properties indicated that Est804 was an alkaline esterase with an optimal pH of 8.0 and a broad optimal temperature in the range of 35−50°C. The optimal activity of free Est804 was calculated to be 112.812 U, and the specific enzyme activity was 48.97 U/mg. The kinetic parameters of Est804 were Km = 0.613 mM, kcat = 12,371 s–1, and Vm = 0.095 mM/min. The results of the fermentative optimization demonstrated that the optimal conditions included 1.5% of inoculation amount, 30 mL of liquid volume, 28°C of the fermentation temperature, and 18 h of the fermentation time. The optimal medium consists of 15.87 g of yeast powder, 8.00 g of glycerol, and 9.57 g of tryptone in 1 L of liquid. The optimized enzyme activity was 1.68-fold higher than that before optimization. Immobilized Est804 exhibited the highest activity under the optimum preparation conditions, including 0.35 g of chitosan dosage, 0.4 mL of an enzyme, and 4 h at 40°C for adsorption. The degradation rates of Cypermethrin (CYP), fenpropathrin (FE), and lambda-cyhalothrin (LCT) by Est804 within 30 min were 77.35%, 84.73%, and 74.16%, respectively. The present study indicated that Est804 possesses great potential for the treatment of pesticide residues on crops and environmental remediation, conducive to the development of SGNH family esterase against pyrethroid accumulation.
... Moreover, ozone can cause negative alternations on food components: loss of some vitamins, phenolic compounds, ascorbic acids, and carotenoids, changes in color, sensory characteristics, and other adverse effects (21)(22)(23). Also, degradation products of pesticide residues after ozone treatment were demonstrated to be more toxic than the parent compounds (24,25). These further have retarded the development of ozone-based technologies. ...
Pesticide residues are of great significant issue that exerted adverse effects on humans. There is a need for effective and non-toxic decontamination of pesticide residues during food processing. In this minireview, the recent advances in the degradation of pesticide residues by photolysis have been firstly described during food processing. The mechanisms of pesticide residues destruction by photolysis were discussed accordingly. Finally, applications of photolysis in the degradation of pesticide residues from beverages, fresh produce, and food rinse waste were also summarized.
... Similarly, both in its gaseous form and in its dissolved form, ozone was investigated for better pesticide reduction efficacies due to its high oxidation potential. Ozonated water washing was feasible and a useful technique for pesticide degradation in aqueous suspensions and fruits and vegetables (Chen, Lin, and Kuo 2013;Wu et al. 2007). Al-Dabbas et al. (2018) observed 98% and 87% reduction in chlorpyrifos and cypermethrin in tomato fruits by ozonated water washing with 0.4 ppm ozone for 30 min. ...
Pesticide residues in the food above the maximum permissible residual limit (MRL) for safe consumption are a severe concern today. Though unit operations employed in domestic and industrial-scale processing of foods such as high-temperature decontamination and chemical washings degrade the agrochemicals and reduce toxicity, eliminating pesticides from the fresh and raw fruits and vegetables with the retainment of nutritional and organoleptic attributes demand appropriate non-thermal technologies. In this review, the potential of novel technologies like the pulsed electric field, high-pressure processing, irradiation, ozone, ultrasonication, and cold plasma for the reduction of pesticides in fruits and vegetables have been discussed in terms of their mechanism of action, playing around factors, advantages, and limitations. All the reviewed non-thermal technologies exhibited promising effects on pesticide degradation with their unique mechanism of action. Also, these techniques' potential to reduce the pesticides below MRLs and yield nontoxic metabolites in fruits and vegetables were analyzed. However, investigating the impact of the technologies on the nutritional and organoleptic quality profile of the commodities at the processing conditions causing noticeable pesticide reduction and the pathways of degradation reactions of various pesticides with each emerging technology should be studied to enhance the applicability.
... Given the desired characteristics of ozone, it is a potential technique for degradation of several pesticides such as diazinon residues in food products including fruit and vegetables in addition to water and wastewaters (Sintuya et al. 2019;Ku et al. 1998, Wu et al. 2007a, b, Chung 2018, Pandiselvam et al. 2020. The elimination rate of pesticides using ozone is affected by various factors such as the food variety and composition, ozone type and concentration, pH, humidity, the treating temperature and time, the physicochemical properties, and initial concentration of the pesticides (Ku et al. 1998;Wu et al. 2007a, b;Chung 2018;TK et al. 2020). ...
Diazinon is known as one of the most commonly used organophosphorus pesticides which influence different pests through inactivating acetyl choline esterase enzymes. Despite diazinon applications, its toxicity to human health could result in a worldwide concern about its occurrence in foodstuffs. Malfunction of brain is considered as the main disorders induced by long time exposure to diazinon. Due to the degradation of diazinon in high temperatures and its susceptibility to oxidation as well as acidic and basic conditions, it could be degraded through several physical (9–94%) and chemical (19.3–100%) food processing procedures (both household and industrial methods). However, each of these methods has its advantages and disadvantages. Normally, the combination of these methods is more efficient in diazinon reduction. To this end, it is important to apply an effective method for diazinon reduction in the food products without affecting food quality or treating human health. It could be noticed that bioremediation by microorganisms such as probiotics could be a promising new method for diazinon’s reduction in several food products.
... However, the elimination of pesticides from the product cannot be considered as the single way to ascertain the safety of the product owing to the formation of degradation products, which can be as harmful as the parent compound (Wu et al., 2007). The products may even be complex and transitory with respect to the ozone concentration and treatment time, yet the potential risks associated with the degradation products are worthy of further research. ...
The need for sustainable food production and the demand for fresh and minimally processed foods have prompted remarkable research in novel food processing technologies that ensure safe and shelf‐stable food for a large population. Long‐established techniques such as heating, drying, and freezing have been associated with nutrient loss and high energy consumption. This trend has drawn attention to the practice of employing ozone in several food applications owing to its significant disinfectant and antimicrobial efficiency. The aqueous form of ozone has been found to show greater efficacy than its gaseous form, with faster decomposition rates leaving no harmful residues. The current study presents an overview of the latest scientific literature on the properties, chemistry, and generation of aqueous ozone, emphasizing the factors affecting process efficiency. The review scrupulously focuses on food decontamination, starch modification, pesticide degradation, and seed germination effects of aqueous ozone, highlighting the optimum processing parameters and salient findings of some major studies. A brief insight into the limitations and future trends has also been presented. Aqueous ozone has been acclaimed to have the potential to cause significant changes in the food matrix that could result in constructive modifications with outcomes entirely dependent on the processing conditions. Indirect and direct reactions involving hydroxyl radical and molecular oxygen atoms, respectively, form the basis of the ozone reaction in aqueous media, providing a distinctive kind of advanced oxidation process that offers certain crucial benefits. With a shorter half‐life in water as compared to air, the rapid decomposition of aqueous ozone to oxygen, leaving no harmful residues, adds to its advantages.
... The acute and chronic risk index values showed that there was no health risk for consumers of Cumilla, Bangladesh, due to the intake of organophosphorus pesticide residues on these vegetables. Pesticide concentrations in vegetable products are known to be reduced by different home processing like washing, peeling, or cooking (Soliman, 2001;Wu et al., 2007;Ling et al., 2011;Yang et al., 2012;Huan et al., 2015). So, future studies should consider processing factors to compensate for reducing or removing pesticides. ...
Organophosphorus pesticides are one of the most commonly used pesticide classes in agriculture in the management of insect pests due to their high efficacy. The extensive use of organophosphorus pesticides can contaminate both the atmosphere and food, which may lead to health problems. In this study, the residue level of organophosphorus pesticides, and their health risk assessment was evaluated on country bean and bitter gourd. Out of forty analysed samples of the country bean, two samples contained multiple residues, seven samples contained single residue. On the other hand, out of forty samples of bitter gourd, one sample contained multiple residues and three samples contained single residue. Among the organophosphorus pesticides, diazinon was the most frequently detected organophosphorus pesticide in country bean and bitter gourd. The highest short-term risks or acute risk (aHI) was below 1.83%, and the highest long-term risk or chronic risk (HQs) was below 10.46% for the country bean and bitter gourd, respectively. Short-and long-term risk assessment results showed that the intake risks of country bean and bitter gourd were acceptable. The health hazard results showed that country bean and bitter gourd consumption in Cumilla, Bangladesh does not pose an acute or chronic risk to human health. However, a routine monitoring system must be established to control the contamination of vegetables with pesticides.
... Several previous works examining similar pesticide residues removing methods were carried out worldwide. Previous work [23] has used dissolved ozone to get rid of four pesticides from vegetable which were methylparathion, parathion, diazinon and cypermethrin and found that low level (1.4 mg/l) of dissolved ozone was capable to oxidize up to 90% of all these pesticides except parathion within 5 minutes. Similar method (dissolved ozone) was followed by a work [24] carried on by using low concentration of dissolved ozone to remove four residues of four pesticide species and recorded a removing rate up to 99% within 30 minutes but it has reported that such removing rate was affected by temperature, concentration of applied ozone gas and preparing dissolved ozone concentration. ...
... Ozone helps to reduce microbial contamination, weight loss and spoilage of fruits. [118] It is more effective than chlorine in reducing plant pathogens, [119,120] and can be applied to inactivate mycotoxigenic fungi such as Aspergillus and Penicillium, and to degrade their mycotoxins. Ozone has also showed the effectiveness in degrading several pesticides used in fruit production. ...
Fruits production and consumption are generally increasing because of consumers’ awareness of healthy nutrition. Fruit quality and safety are both important since fruits are vulnerable to microbial deterioration due to their nutritional composition. Spoilage microorganisms invade fruits during the period of growth and mainly during post-harvest handling. Physical damage of the fruit tissue may lead to microbial contamination. Fortunately, fruit spoilage is preventable and this discussion intends to provide an overview of the sources, distinctive factors, and causes of fruit spoilage and some of the commonly adopted methods and practices to prevent fruit spoilage.
... Similarly, both in its gaseous form and in its dissolved form, ozone was investigated for better pesticide reduction efficacies due to its high oxidation potential. Ozonated water washing was feasible and a useful technique for pesticide degradation in aqueous suspensions and fruits and vegetables (Chen, Lin, and Kuo 2013;Wu et al. 2007). Al-Dabbas et al. (2018) observed 98% and 87% reduction in chlorpyrifos and cypermethrin in tomato fruits by ozonated water washing with 0.4 ppm ozone for 30 min. ...
Pesticide residues in the food above the maximum permissible residual limit (MRL) for safe consumption are a severe concern today. Though unit operations employed in domestic and industrial-scale processing of foods such as high-temperature decontamination and chemical washings degrade the agrochemicals and reduce toxicity, eliminating pesticides from the fresh and raw fruits and vegetables with the retainment of nutritional and organoleptic attributes demand appropriate non-thermal technologies. In this review, the potential of novel technologies like the pulsed electric field, high-pressure processing, irradiation, ozone, ultrasonication, and cold plasma for the reduction of pesticides in fruits and vegetables have been discussed in terms of their mechanism of action, playing around factors, advantages, and limitations. All the reviewed non-thermal technologies exhibited promising effects on pesticide degradation with their unique mechanism of action. Also, these techniques' potential to reduce the pesticides below MRLs and yield nontoxic metabolites in fruits and vegetables were analyzed. However, investigating the impact of the technologies on the nutritional and organoleptic quality profile of the commodities at the processing conditions causing noticeable pesticide reduction and the pathways of degradation reactions of various pesticides with each emerging technology should be studied to enhance the applicability.
... Among them, organophosphorus (OP) and pyrethroid (PYR) pesticides are the most extensively used (Chen et al., 2002). OP and PYR can penetrate the crop matrix and maybe converted to the oxidation and hydrolysis products which are more toxic to humans (Stratton & Corke, 1982;Wu, Luan, Lan, Hung Lo, & Chan, 2007). OP and PYR have been detected in human biological samples (Becker et al., 2006) and they have been demonstrated as neurotoxin insecticides. ...
A simple, sensitive and environmentally-friendly method for determining organophosphorus and pyrethroid pesticides in vegetables was developed to better evaluate the risk of consuming them. The pesticides in vegetables were extracted, purified and concentrated by using the QuEChERS (quick, easy, cheap, effective, rugged and safe method) combined DLLME-SFO (dispersive liquid–liquid microextraction based on solidification of floating organic droplet)techniques. Thekey parameterswere optimizedthrough orthogonal arrayexperimental design and statistical analysis. The linearity of the calibration curves was satisfied in matrix-matched standard solution with R2 ≥0.99. The limits of detection and limits of quantification were 0.3–1.5 and 0.9–4.7μg/kg, respectively. The average recoveries of pesticides were 61.6–119.4% with relative standard deviations<16.1%. Furthermore, the method was applied successfully to analyse the pesticides in 15 pairs of organic and conventional vegetables. These results reflect the efficiency, reliability and robustness of the developed method.
... To reduce the potential health risks of pesticide residues in foods, various technologies have been developed, including ultrasound, 6,7 microorganisms, 8 ozonation, [9][10][11] ultraviolet irradiation 12 and chlorine. 13,14 Although some of these methods degraded pesticide residues in foods to a certain extent, they still suffer from low efficiency, formation of by-products, and damage to the flavor, color and texture of products. ...
BACKGROUND
Pesticides have been widely used to control pests on agricultural products in China, and large amounts of pesticide residues have caused a serious threat to human health. Thus, developing a high‐efficiency pesticide degradation method for fresh vegetables represents a great challenge. The present study investigated the effects of dielectric barrier discharge (DBD) plasma on the degradation of malathion and chlorpyrifos in aqueous solutions and on lettuces.
RESULTS
DBD treatment significantly degraded malathion and chlorpyrifos in water and on lettuce. After cold plasma treatment at 80 kV for 180 s, the degradation efficiency of malathion (0.5 μg mL⁻¹) and chlorpyrifos (1.0 μg mL⁻¹) in aqueous solutions reached 64.6% and 62.7%, respectively. The degradation intermediates were explored by HPLC‐mass spectrometry and the DBD plasma degradation pathways of malathion and chlorpyrifos were proposed. There was no significant damage to the quality of lettuces, including color and chlorophyll content, after plasma treatment. Ascorbic acid decreased significantly during long‐term treatment with DBD plasma. To ensure the quality of lettuces during processing, the treatment time was shortened to 120 s. Under this condition, the degradation efficiency of malathion (0.5 mg kg⁻¹) and chlorpyrifos (1.0 mg kg⁻¹) on lettuces was found to be 53.1% and 51.4%. More importantly, we noted that cold plasma treatment significantly inactivated the microorganisms on lettuces.
CONCLUSION
The results of the present study show that cold plasma is an effective and safe method for the degradation of organic pesticide residues on fresh vegetables at the same time as retaining the original quality. © 2020 Society of Chemical Industry
... Several conventional treatment methods for pesticides removal from contaminated water has been used including photocatalytic degradation, combined photo-Fenton and biological oxidation, advanced oxidation processes, nanofiltration and ozonation. [8][9][10] These methods are very expensive. Thus, there is a need for green and advanced pesticide removal to meet environmental quality requirements improving ecological system. ...
The quantitative removal of atrazine, diazinon, chlorothalonil, ametryn, chlorpytrifos and dimethametryn from contaminated water was studied using flower of the Typha latifolia. The surface chemistry of this adsorbent was analyzed by FT-IR and the adsorption efficiency was studied using batch adsorption technique. The potential experimental parameters studied were pH (5-9), the dose of adsorbent (0.1-0.5 g), contact time (100-140 min), shaking speed (100-300 rpm) and initial pesticide concentration (3.15-100 jug L-1). The effects of concentration and contact time at the optimum conditions were used to study equilibrium and kinetic models for pesticide sorption. Results of the sorption equilibria were found to fit better to the Langmuir isotherm model than the Freundlich adsorption model indicating monolayer homogeneous surface conditions. On the other hand, kinetics of all pesticides sorption on the adsorbent was well defined by the pseudo-second-order model. The results obtained showed that the use of this plant be considered as one of the promising, natural, easily accessible and low-cost adsorbent for efficient and quantitative removal of pesticides from contaminated water.
... Therefore, it is necessary to study the removal or degradation methods of pesticide residues in the environment. Among various technologies studied to clean up residual pesticides, such as chemical oxidation, biotreatment, catalytic treatment, and filtration (Wu et al. 2007), biodegradation was considered an environment friendly approach. Many genetically engineered microorganisms (GEMs) capable of biodegrading pesticides were constructed by recombinant DNA technology (Ingham et al. 1995;Lan et al. 2006;Chungjatupornchai et al. 2011;Khodi et al. 2012). ...
Abstract Chemical pesticides are used widely and their residues are found in the environment. Pesticide pollution has become a global problem. To find an economical, effective and safety way to degrade residues of pesticides in environment, we constructed a genetically engineered bacterium (GEB) having the ability to degrade pesticides, emit green fluorescence and has a containment system by using a dual plasmid expression system. One plasmid contains the genes of enhanced green fluorescent protein (EGFP) and carboxylesterase B1 (CarE B1), which were cloned downstream of lambda PL promoter and expressed constitutively. The gene of CarE B1 encodes an insect-detoxifying enzyme possessing the degradability to organochloride pesticides, organophosphorus pesticides, carbamates, and pyrethoid insecticides. The other is the conditional suicide plasmid for containment system, in which the lethal gene used was the nuclease gene of Serratia marcescens without the leader-coding sequence and was placed downstream of T7 promoter. The GEB has wide prospects of application on cleanup of pesticide residues with its degradability to several pesticides and containment system.
... The results revealed that ozone fumigation can degrade pesticide residues more rapidly than those without ozone fumigation. The removal efficiency of pesticide residues may result from the oxidizing properties of ozone that can cause oxidation reactions with the pesticide residues and other organic substances for the degradation and removal of the pesticide residues from vegetable (Amvrazi 2011;Wu et al. 2007). ...
This research aims to apply gaseous ozone to degrade pesticides (cypermethrin and dicofol) residues in dried basil leaves and to investigate their qualities after fumigation. Sweet basil, holy basil, hairy basil, and tree basil were fumigated with 200 mg/L gaseous ozone. The result showed that half-life of cypermethrin and dicofol in dried basil under ozone fumigation were in the range of 13.1–31.6 and 9.4–18.9 min, respectively. Ozone fumigation exhibited at least 99.9% reduction of pesticide residue in comparison with self-degradation. In addition, this process does not significantly affect phenolic compounds and antioxidants in dried basil at 95% confidence level.
... 12 The efficacy of ozone in pesticide removal was reported for lettuce, grape, apple, mustard, lemon, orange, grapefruit, corn, wheat, and lychee. [13][14][15][16] Pulsed electric fields with 8-20 kV cm −1 electric field strength (EFS) and 6-26 pulses (P) achieved the removal of methamidophos and chlorpyrifos spiked in apple juice. 17 Acoustic cavitation generated by ultrasonic radiation destroys the chemical and organic contaminants such as pesticides in aqueous solution. ...
BACKGROUND
The consumption of pesticide‐contaminated sour cherries as fruit or juice has become a major health concern, and so the search for alternative processing technologies, such as pulsed electric fields (PEF), ozone (O), and ultrasonication (US) has intensified. The objectives of this experimental study of sour cherry juice were fourfold: (1) to quantify the removal efficiency of new processing technologies (PEF, O, US), and their combinations, for the pesticides chlorpyrifos ethyl, τ‐fluvalinate, cyprodinil, pyraclostrobin, and malathion; (2) to detect their impact on physical, bioactive, and sensory properties; (3) to determine their microbial inactivation levels for Escherichia coli O157:H7, Bacillus cereus, Pseudomonas syringae subs. Syringae, and Penicillum expansum; and (4) to jointly optimize multiple responses of physical, quality, and sensory properties, pesticides, and microbial inactivation.
RESULTS
Except for all the O treatments, the physical, bioactive and sensory properties of sour cherry juice were not adversely affected by the treatments. The joint optimization suggested PEF1 (24.7 kV cm⁻¹ for 327 μs), PEF2 (24.7 kV cm⁻¹ for 655 μs), PEF2 + O + US, US, and PEF2 + O as the five best treatments. PEF2 + O + US best achieved both pesticide removal and microbial inactivation.
CONCLUSION
PEF2 + O + US provided promising reductions in pesticide and microbial loads. © 2019 Society of Chemical Industry
Pesticides production, consumption, and disposal around the world are raising concerns day by day for their human and environmental health impacts. Among developing treatment technologies, ozonation has attracted the attention of many researchers in recent years. It is an emerging and promising technology for removing pesticides in the aqueous environment and degrading the residual pesticides from the fruits and vegetables (F&V) surfaces. This systematic review presents an extensive study of the degradation of different types of residual pesticides from F&V using ozonation, micro‐ and nanobubble (MNB) ozonation, or other advanced techniques such as microwaves/ultrasonication and advanced oxidation process. This review compiles the studies that reported the effect of MNB size on the dissolution of ozone gas in the washing medium and its effect on the degradation of residual pesticides from F&V. The mechanism and routes of pesticide degradation and how integrating MNB technology (MNBT) can help overcome economic losses, reduce health issues for consumers, and save the environment from harmful chemicals used in the pesticides are also discussed. The article encourages the development and utilization of MNBT not only in agriculture, but aquaculture, fisheries, food industries, food storage, and packing, for reducing/degrading the residual pesticides from foods and support environmental sustainability as well as improve international trade.
Laser-induced graphene (LIG) has gained popularity for electrochemical water disinfection due to its efficient antimicrobial activity when activated with low voltages. However, the antimicrobial mechanism of LIG electrodes is not yet fully understood. This study demonstrated an array of mechanisms working synergistically to inactivate bacteria during electrochemical treatment using LIG electrodes, including the generation of oxidants, changes in pH-specifically high alkalinity associated with the cathode, and electro-adsorption on the electrodes. All these mechanisms may contribute to the disinfection process when bacteria are close to the surface of the electrodes where inactivation was independent of the reactive chlorine species (RCS); however, RCS was likely responsible for the predominant cause of antibacterial effects in the bulk solution (i.e., ≥100 mL in our study). Furthermore, the concentration and diffusion kinetics of RCS in solution was voltage-dependent. At 6 V, RCS achieved a high concentration in water, while at 3 V, RCS was highly localized on the LIG surface but not measurable in water. Despite this, the LIG electrodes activated by 3 V achieved a 5.5-log reduction in Escherichia coli (E.coli) after 120-min electrolysis without detectable chlorine, chlorate, or perchlorate in the water, suggesting a promising system for efficient, energy-saving, and safe electro-disinfection.
Pesticide residues on food are threatening human health and wellbeing, ecological security. Food processing is one of the necessary ways to eliminate residues to guarantee the safety and sustainable development of the environment. This review outlines the mechanisms, applications, and factors influencing the efficiency as well as their limitations of pesticide residue elimination technologies. Conventional thermal processing technologies like drying, blanching, baking, and roasting have been proved to reduce pesticides extensively whereas sometimes concentration effects occur, and more toxic metabolites or by-products are generated. Additionally, the negative effects on quality attributes of fruits and vegetables (F&V) should be considered. Several innovative non-thermal processing technologies like ultrasound, cold plasma, high-pressure processing, and pulsed electric fields have flourished currently, which show great ability to eliminate pesticide residues significantly with minimal impact on the quality of F&V. In particular, heat-sensitive nutrients like ascorbic acid, phenolics, and carotenoids would retain to a great extent. Similarly, these technologies have their limitations. Furthermore, there is much information about combined processing technology affecting the pesticide behaviors of F&V. Finally, the future developments for pesticide elimination of these technologies are identified and discussed.
BACKGROUND
Treatment by ozone water is an emerging technology for the degradation of pesticide residues in vegetables. The ozone dissolved in water generates hydroxyl radicals (·OH), which are highly effective in decomposing organic substances, such as malathion and carbosulfan.
RESULTS
We found that washing pak choi with 2.0 mg L⁻¹ ozone water for 30 min resulted in 58.3% and 38.2% degradation of the malathion and carbosulfan contents respectively, and the degradation rates of these pure pesticides were 83.0% and 66.3% respectively. In addition, the ‘first + first’‐order reaction kinetic model was found to predict the trend in the pesticide content during ozone water treatment. Based on investigations by gas chromatography–mass spectrometry combined with the structures of the pesticides, the by‐products generated were identified. More specifically, the ozonation‐based degradation of carbosulfan generated carbofuran and benzofuranol, whereas malathion produced succinic acid and phosphoric acid. Although some new harmful compounds were formed during degradation of the parent pesticides, these were only present in trace quantities and were transient intermediates that eventually disappeared during the reaction.
CONCLUSION
Our results, therefore, indicate that ozone water treatment technology for pesticide residue degradation is worthy of popularization and application. © 2022 Society of Chemical Industry.
Food contamination is a critical problem that necessitates ongoing food pathogen control at every stage of the manufacturing process. In the food industry, it is critical to maintain product quality and safety. They can be accomplished in a variety of ways, some of which are more technologically advanced than others. The role, contribution, importance, and influence of ozone as a disinfectant used to regulate and eliminate the presence of unfavourable bacteria in food products, as well as to extend their shelf life and remove unwanted odours, are discussed in the study. Several researchers have studied the qualities and applications of ozone, demonstrating that ozone treatment technology may be used on a wide range of foods, including fruits, vegetables, spices, meat and seafood, and beverages. Besides food industry, ozone is also used in agriculture crop production in the way of soil application, foliar spraying and irrigation. A combination of such papers, as described in this review, can be helpful in determining acceptable ozone treatment parameters as well as factors affecting improved food quality and safety. It also includes a critical assessment of the benefits and drawbacks of ozone's use in the food industry.
Dissipation of an organophosphorus pesticide, trichlorfon, in natural and waxed apples during storage was studied. The results showed that the trichlorfon content in natural and waxed apples decreased by 85% and 64%, respectively, during storage. The morphology of the surface film was dense and regular, which resulted in a higher water vapor resistance and a lower respiration rate in the waxed apples. This indicates that waxing affected the dissipation of pesticide residues in the apple storage environment, increasing food safety risk. Ozone was used to remove the residual pesticides on the apple surface. The trichlorfon degradation rate reached 73%. The ozone treatment had no effect on the surface color of the apple, which means that the fruit can be pre-treated with ozone prior to waxing or storage.
Recently an advanced oxidative process (AOP) combining H2O2 and UV-C light was observed to be effective at controlling Listeria monocytogens and Escherichia coli O157:H7 and degrading chlorpyrifos residues on the surface of apples. Little is known about the application of AOP for the degradation of other pesticide residues. This study examined degradation of boscalid, pyraclostrobin, fenbuconazole and glyphosate by 3% (w/v) H2O2, UV-C (254 nm) irradiation and their combination on apple skin and glass. The extent of degradation was not significantly different between the AOP and optimal individual treatment. However, treatment susceptibility was different with glyphosate most effectively degraded by H2O2 exposure (up to 98% on apple, 3% (w/v) H2O2 at 30⁰C for 15 min) while boscalid, pyraclostrobin and fenbuconazole were more effectively degraded by UV-C (up to 88%, 100% and 70% degradation after ∼11,000 mJ/cm²). Suggestions for possible causes of degradation are proposed.
The piezoelectric direct discharge (PDD) is a
comparatively new type of atmospheric pressure
gaseous discharge for production of cold plasma.
The generation of such discharge is possible
using the piezoelectric cold plasma generator (PCPG)
which comprises the resonant piezoelectric transformer (RPT)
with voltage transformation ratio of more than 1000,
allowing for reaching the output voltage >10 kV
at low input voltage, typically below 25 V.
As ionization gas for the PDD, either air or various gas mixtures are used.
Despite some similarities with corona discharge
and dielectric barrier discharge,
the ignition of micro-discharges directly at the ceramic
surface makes PDD unique in its physics and application potential.
The PDD is used directly, in open discharge structures,
mainly for treatment of electrically nonconducting surfaces.
It is also applied as a plasma bridge
to bias different excitation electrodes,
applicable for a broad range of substrate materials.
In this review, the most important architectures
of the PDD based discharges are presented.
The operation principle, the main operational characteristics
and the example applications, exploiting the specific properties of
the discharge configurations, are discussed.
Due to the moderate power achievable by PCPG,
of typically less than 10 W, the focus of this review is on applications
involving thermally sensitive materials, including
food, organic tissues, and liquids.
Recently an advanced oxidative process (AOP) combining H 2 O 2 and UV-C light was observed to be effective at controlling Listeria monocytogens (Murray et al., 2018) and Escherichia coli O157:H7 and degrading chlorpyrifos residues on the surface of apples (Ho et al., 2020). Little is known about the application of AOP for the degradation of other pesticide residues. This study examined degradation of boscalid, pyraclostrobin, fenbuconazole and glyphosate by 3% (w/v) H 2 O 2 , UV-C (254 nm) irradiation and their combination on apple skin and glass. The extent of degradation was not significantly different between the AOP and optimal individual treatment. However, treatment susceptibility was different with glyphosate most effectively degraded by H 2 O 2 exposure (up to 98% on apple, 3% (w/v) H 2 O 2 at 30□C for 15 min) while boscalid, pyraclostrobin and fenbuconazole were more effectively degraded by UV-C (up to 88%, 100% and 70% degradation after ~11,000 mJ/cm ² ). Suggestions for possible causes of degradation are proposed.
Agricultural pesticide use is ongoing and consumer concern regarding the safety of pesticide residues on produce has generated interest in techniques that can safely reduce residues post-harvest. Recently an advanced oxidative process has shown promise in substantial residue reduction on the surface of produce. Given the potential for oxidative transformation of pesticides to generate transformation products with greater toxicity than the parent residue, take for example the oxon products of the organophosphorus insecticides, it is important to consider what transformation products are generated by pesticide exposure to an oxidative process and their potential toxicity. In this study, previously published transformation products of boscalid, pyraclostrobin, fenbuconazole and glyphosate were identified after exposure to 3% hydrogen peroxide, UV-C irradiation or their combination in an advanced oxidative process on glass, their oral toxicity, carcinogenicity and developmental toxicity were identified in-silico and an initial tier hazard assessment was conducted. Of the 87 total structures that were searched for, 53 were detected by UPLC-QTOF-MS and identified by mass spectra: 15, 13, 22 and 3 structures for boscalid, pyraclostrobin, fenbuconazole and glyphosate respectively, including the parent residues. Oral toxicity of the transformation products of pyraclostrobin and glyphosate was similar to or lower than the parent residue. Several transformation products of boscalid and fenbuconazole were estimated to be significantly more orally toxic than their parent residues. While the majority of the transformation products of boscalid, pyraclostrobin and fenbuconazole were predicted to be carcinogenic there were 11 that were consistently identified to have carcinogenic potential by several assessments. 29 of the 53 molecules were predicted to be probable developmental toxicants. An initial tier hazard assessment was conducted for Cramer rules classification and mutagenicity using the threshold of toxicological concern approach and predicted rat oral LD50. Two exposure scenarios were considered, one highly protective considering each transformation product to be at the highest maximum residue limit (MRL) for the pesticide and whole produce consumption at the highest consumption rate from the USEPA Exposures Handbook, the other considering only apple consumption with the relevant MRL. As indicated by the hazard assessment, several transformation products of boscalid, pyraclostrobin and fenbuconazole should be strongly considered for further testing, either by quantifying their production or in-vivo and in-vitro toxicity tests due to their predicted toxicity and associated hazard.
محصولات تازه از قبیل میوهها و سبزیجات ناقل میکروارگانیسمهای بیماریزا شناخته شدهاند که اغلب منجر به شیوع بیماریهای انتقال یافته از غذا و خطرات مشابه در سلامت عمومی میشوند. در حین فراوری محصولات تازه، جهت از بین بردن تودهی میکروبی که از عمل شستشو برجای میمانند، پاککنندهها و ضدعفونی کنندههای قوی مورد نیاز هستند. درعین حال که چنین پاک کنندهها و ضدعفونی کننده ها به عنوان یک عامل ضدمیکروبی باید بسیار موثر باشند، همزمان آنها باید مقرون به صرفه، سازگار با محیط زیست، بیخطر برای سلامت عمومی و دارای اثر کمی برروی خصوصیات تغذیهای و حسی محصولات تازه نیز باشند. در این مطالعه، اثر ضدعفونیکنندههای مختلف شیمیایی از جمله ازون، دیاکسیدکلر، هیدروژن پراکسید، پروکسی استیک اسید و آب اکسیدکننده الکترولیز شده برای کاهش فساد میکروبی و افزایش عمر مفید محصولات تازه بدون افت کیفیت محصولات نهایی، مرور و بررسی میشود .بنابراین هدف از این مقاله بررسی ویژگیها و کاربرد ضدعفونیکنندههای نوین شیمیایی برای محصولات تازه از قبیل میوهها و سبزیجات میباشد.
Since the beginning of the widespread use of pesticides, their removal from food has become a serious concern. In this study, the removal of residual pesticides (malathion and carbosulfan) from pak choi via treatment with ozonated water was investigated. Under the optimal treatment conditions, i.e., 2.0 mg/L ozonated water and a treatment duration of 15 min, malathion and carbosulfan were degraded by 53.0 and 33.0%, respectively, without any significant changes in color. Even though there was a slight decrease in vitamin C content (∼7.9 mg/100g) following the treatments, a significant decrease in the microbial colonies on the vegetables was observed. Additionally, the pesticide degradation mechanism showed good fitting with a “first+first”-order kinetic model (R² > 0.9), and the slope (k) indicated that ozone had a more prominent degradation effect on malathion than on carbosulfan. Therefore, this study provides a theoretical basis for controlling agricultural pesticide residues in household applications.
This study optimized the method for ozone (O3) degradation of prometryn in the clam Ruditapes philippinarum and evaluated toxicity changes during ozone degradation. The gas chromatography method for the detection of prometryn was appropriately improved. The linear range was 5 to 500 ng/mL, with a correlation coefficient of 0.9964. The addition concentration of prometryn was 0.025 to 0.100 mg/kg, the recovery was 77.97 to 85.00%, the relative standard deviation (n = 6) was 2.36 to 7.86%, and the limit of detection was 0.3 μg/kg. Using the central composite design in two experiments, ozone as gas and ozone dissolved in water, the effect of degradation rate was studied on three variables: ozone concentration, temperature, and exposure time. Ozone as gas and ozone dissolved in water have the same degradation effect on prometryn. The O3 concentration was 4.2 mg/L, the temperature was 40°C, the exposure time was 10 min, and the maximum degradation rate was 89.94 and 89.69% for the two experiments, respectively. In addition, the toxicity of ozone degradation products was evaluated using buffalo rat liver cells. After ozone treatment for 30 min, the toxicity of the ozone degradation products was reduced to 52.15% compared with that of prometryn itself. The toxicity of the ozone degradation products increased slightly when the ozonation time was prolonged; the toxicity at 180 min was greater than that of the parent compound prometryn. Overall, the application of ozone degradation of pesticide residues is a promising new technology. This study determined better degradation conditions for prometryn in R. philippinarum and also provided a theoretical basis for the widespread use of ozone technology in the future.
Highlights:
In recent years, prometryn was utilized as watergrass remover in the aquaculture industry, resulting in the accumulated residual in the aquatic products. The present study focuses on the ozone degradation of prometryn in the Ruditapes philippinarum. The ozone concentration in water increased along with the injection time (60min). The contents of hydroxyl (·OH) and superoxide (O2·-) radicals increased along with the ozone injection time. The effects of temperature, pH, prometryn initial concentration and ozone concentration on the removal efficiency of prometryn were evaluated. The maximum removal efficiency of 86.12% was obtained under the conditions of pH 7, prometryn initial concentration 0.05 mg/kg and the ozone concentration 4.2 mg/L at 28 °C for 30 min. Ion chromatography (IC) and Fourier transform infrared (FT-IR) spectroscopy results show that the S and N atoms in the outer layer of the triazine ring during the prometryn degradation process were oxidized and removed. A total of 30 intermediate compounds were identified using the gas chromatography-mass spectrometry (GC-MS) method. Combined with the IC and FT-IR results, three possible degradation pathways of prometryn were proposed. The prometryn was finally degraded into some small molecules with reduced toxicity by 63.16% for 120 min ozonization treatment. Overall, our work provides a novel approach for prometryn degradation in Ruditapes philippinarum, which can be extended for removing the residues of agricultural and veterinary drugs in other aquatic products.
In this research, the capability of ozonation and peroxone treatment for the simultaneous disinfection and decontamination of wash water from the fresh-cut industry has been investigated at pilot plant scale (10 L). The removal efficiency of six organic microcontaminants (OMCs) (four of them priority substances) and the inactivation of two foodborne pathogens (Escherichia coli O157:H7 and Salmonella enteritidis) in synthetic fresh-cut wastewater (SFCWW) has been assessed. Ozonation and peroxone (O3 with 20 mgL-1 of H2O2) process has been investigated under several operational conditions: natural SFCWW pH (6.25) and basic pH (11), and two different initial ozone production (0.09 and 0.15 gO3 L-1 h-1). Results showed that the highest efficiency for OMCs removal (85%) and pathogen inactivation (>5-Log) were obtained with ozonation treatment at natural pH. OMCs degradation was obtained after 120 min of treatment with an ozone dose of 27.4 mgO3 L-1. First order kinetic constant of each OMC degradation was obtained, and two clear different groups have been identify based on their degradation profiles, which have been correlated with their chemical structure. G1-OMC [terbutryn > buprofezin > azoxystrobin] > G2-OMC [imidacloprid > simazine > thiamethoxam]. As for bacterial inactivation, up to 10 min of treatment time and an ozone dose of <8.6 mgO3 L-1 were required to reach the detection limit (2 CFU mL-1), showing E. coli O157:H7 a higher susceptibility to be inactivated (k: 2.79 min-1) than S. enteritidis (k: 1.47 min-1). Moreover, from the techno-economical and toxicological assessment of the treated water with the best operational condition, can be highlighted: i) a slight acute toxicity for V. fischeri (47 ± 2.3% of luminescence inhibition), ii) an acute toxicity for Daphnia magna (100% of immobilization) and iii) a total cost of the treatment of 1.16 € m-3.
The native microflora survival and quality retention of fresh-cut onions treated by ozonated water (OW) with ozone concentration of 1.4 mg L⁻¹, for 1, 3, and 5 min during storage at 4°C for 14 days were investigated. The pesticide residue removal effect of OW treatment for 5 min was also determined. The results show that all OW treatments significantly inhibited the growth of aerobic bacteria, coliforms, and yeasts during storage, with the OW treatment for 5 min allowing the lowest growth rates. OW treatment for 1 min significantly reduced the weight loss of fresh-cut onions during a longer storage time (8–14 d). All OW treatments reduced the respiration rate and the softening of fresh-cut onions, exhibiting better overall quality retention than the control samples. In addition, OW treatment for 5 min significantly reduced the residual levels of five tested pesticides (dimethyl dichlorovinyl phosphate, cypermethrin, chlorpyrifos, methomyl, and omethoate) compared with water treatment. These results indicate that treatment with OW is a promising strategy to control the microbial growth, preserve the quality and reduce pesticide residual of fresh-cut onions.
Abbreviations: OW: ozonated water; PCA: plate count agar; VRBA: violet red bile agar; PDA: potato dextrose agar; DDVP: dimethyl dichlorovinyl phosphate
Catalytic ozonation is promising as one of the advanced oxidation processes because of its effective use of ozone and its improved treatability of organic compounds through radical reactions. In this article, we investigated the feasibility of microporous silicates as a potential catalyst for a catalytic ozonation process. Organophosphorus insecticide, dichlorvos (DDVP), was employed as a model chemical for assessing conventional ozonation and catalytic ozonation, because its oxidative intermediate is toxic and is not degraded by direct ozonation. It was found that ozone was well adsorbed and simultaneously decomposed in microporous silicates, resulting in the production of possible radical species. In the presence of microporous silicates, radical reactions by decomposed ozone were evidenced by phosphate ion release that shows a degradation of a toxic intermediate of DDVP. Accordingly, cytotoxicity was successfully decreased. In a continuous treatment process combining a conventional ozonation vessel and a microporous silicate column for an effective use of residual ozone, enhanced degradation of DDVP was demonstrated by a decrease of DOC, an increase of the PO4(3-) concentration and reduction in the cytotoxicity. This new treatment mechanism is likely to be promising as an advanced water treatment process particularly when we think about better toxicity reduction of wastewaters.
An attempt was made to detect pesticides remaining in river water and raw water for tap water supply, located in an agricultural area. As a result, 11 kinds of pesticides were detected. The residual pesticides in water were also degraded to by-products, since chlorine is a strong oxidant that does not exist in natural conditions. Organophosphate pesticides containing P = S bonds were easily degraded and produced oxons (P = O) as a primary by-product. Thiobencarb was also degraded by chlorination, producing chlorobenzyl alcohol, chlorotoluene, chlorobenzyl chloride, chlorobenzoic acid and chlorobenzyl aldehyde as chlorination by-products. Also, when thiobencarb was detected in raw water, the above by-products were detected in the filtered water in a purification plant for water supply. Therefore, the management and control of pesticides in drinking water and ambient water quality management should include testing for chlorination by-products.
The effect of radical scavengers such as bicarbonate and tert-butanol on the MnII catalysed ozonation of atrazine, an important herbicide and well-established radical probe substance, was studied using a conventional gas bubble-contacting column. It was found that the presence of a small amount of MnII (0.3–1.2 mg/l) greatly increased the degradation rate of atrazine, with the formation of by-product compounds of a lower molecular weight and a greater polarity (as indicated by shorter retention times in HPLC chromatography). However, the presence of either bicarbonate or tert-butanol had a negative effect on the degradation of atrazine. With an increase of bicarbonate concentration, the oxidation rate of atrazine by MnII-catalysed ozone was substantially reduced and a correspondingly higher residual ozone was observed. In the presence of tert-butanol, greater reductions of the degradation rate of atrazine were observed and the decomposition of ozone was greatly retarded, resulting in a higher residual ozone; this was the case for either ozone oxidation alone or MnII-catalysed ozone oxidation. These results appear to confirm that the degradation of atrazine by ozone in the presence of MnII follows a radical mechanism. It is believed that MnII catalyses the decomposition of ozone through the formation of intermediate manganese species (such as MnIV), leading to the generation of hydroxyl radicals.
For drinking water companies, it is important to predict the lifetime of granular activated carbon (GAC) for the removal of pesticides. Full-scale experiments in pilot GAC filters are expensive and time-consuming, but fast laboratory experiments do not have the accuracy necessary for a realistic prediciton of the breakthrough curves of pesticides. The problems with these experiments and the models used for the translation of these experiments to full-scale columns are discussed.Although at the moment laboratory experiments do not predict full-scale behaviour satisfactorily, they are very useful in evaluating new combinations of treatment methods or new adsorbents. In the small-scale column tests, combinations of ozone/activated carbon and nanofiltration/activated carbon are evaluated. Also, the performance of activated carbon fibres are evaluated on a small scale.
The effectiveness of chlorinated and ozonated water dips in the dissipation of azinphos-methyl, captan and formetanate hydrochloride in solution and on fresh and processed apples was examined. All three pesticides in model systems solution decreased 50–100% with chlorine and ozone treatment. Captan and formetanate-HCl were both rapidly degraded in 50 and 500 mg liter−1 chlorine solutions at pH 7 and 10.7. Ozonation was also effective in degrading the pesticides. Rate of degradation of the pesticides generally increased at higher pH and temperature. Pesticide residues on fresh apples and in processed products were also reduced by chlorine and ozone washes; chlorine (500 mg liter−1) being the most effective wash treatment. Ozone wash at 0.25 mg liter−1 was not as effective owing to its low concentration, its instability in water and the high organic content of the wash water.
The decomposition of diazinon in aqueous solution by ozonation was studied under various solution pH values, gaseous ozone dosages, gaseous pressure, alkalinity levels and solution temperatures. Ozonation has been shown to be feasible for achieving nearly complete decomposition of diazinon within 1 h. The surface tension of aqueous solution was found to be affected by the dissolved diazinon and influenced the oxidation mechanism of diazinon by ozonation in aqueous solution. The gas–liquid reaction model was well used to describe the transfer and reaction behaviors of reacting species in the system. The quasi-global kinetics based on a simplified consecutive reaction scheme was developed to describe the temporal behavior of diazinon decomposition in aqueous solution by ozonation.
A Penicillium lilacinum BP303 was found to be able to degrade various organophosphorus pesticides by cleaving PO in the phosphotriesters bond and PS linkage in the phosphothiolesters effectively. The novel fungal enzyme hydrolyzing methyl parathion, parathion, paraoxon, coumaphos, demeton-S, phosmet, and malathion has been purified to homogeneity and characterized. It is a monomeric structure with a molecular mass of 60,000 Da, a pI of 4.8, and the enzyme activity was optimal at 45 °C and pH 7.5, The activities were strongly inhibited by Hg2+, Fe3+, ρ-chloromercuribenzoate, iodoacetic acid, and N-ethylmaleimide, while Cu2+, β-mercaptoethanol, dithiothreitol, dithioerythritol, glutathione, and detergents slightly activated the enzyme. As judged by catalytic efficiencies, paraoxon is the preferred substrate.
Pesticide residues in vegetables and fruits continue to generate concern in the general population mainly about their potential long term adverse effects such as cancer. The pesticides currently in use include a wide variety of compounds belonging to different chemical classes. More than 800 chemicals marketed as multiple formulations, are used in the European Union, as insecticides, herbicides, fungicides. Pesticides have been considered potential chemical mutagens. Experimental data revealed that various agrochemical ingredients possess mutagenic properties inducing gene mutation, chromosomal alteration or DNA damage. The genotoxic potential for agrochemical ingredients is generally low: they give positive results in few genotoxicity tests. In human biomonitoring studies genetic damage associated with pesticides has been detected for high exposure levels and intensive use. The genetic effects depend on quantity and variety of chemical formulations consumed. Improvements of agricultural practices and of safety of work conditions has reduced the genotoxic hazard. The most recent studies failed to reveal genotoxic damage. This evidence suggests a negligible risk for general population exposed to very low levels of residues.
Metolachlor [2-chloro-N-(2-methyl-6-ethylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] or methyl parathion [O,O-dimethyl-4-nitrophenyl phosphorothioate] at (1–2) × 10−4 M was rapidly decomposed using a photoassisted Fenton reaction (Fe3+/H2O2/u.v.). At 10−2 M H2O2 and blacklight u.v. (300–400 nm) comparable in intensity to midday summer sunlight, metolachlor reacted in 8 min and was completely mineralized to HCl (40 min), inorganic N (7:1 ratio of NH3 and HNO3, > 2 h), and CO2 (6 h). The aromatic ring was mineralized in 2.5 h. The transient organic intermediates identified—chloroacetate, oxalate, formate, serine, and several derivatives with the aromatic ring intact—indicate non-selective attack on the molecule. Under the same conditions, methyl parathion reacted in 5 min giving quantitative yields of HNO3 and H2SO4 (5 min) and H3PO4 (30 min). Oxalic acid, 4-nitrophenol, dimethyl phosphoric acid, and traces of O,O-dimethyl-4-nitrophenyl phosphoric acid were identified as intermediates and shown to be oxidized further. Solutions of 14C-4-nitrophenol evolved HNO3 concomitant with disappearance of starting material, and evolved 14CO2 within 45 min. Based on the intermediates and their yields the initial oxidant attack on methyl parathion appears to be on the PS group leading to elimination of 4-nitrophenol and dimethyl phosphate. The results suggest that photoassisted Fenton oxidation can be a mild and effective remedy for dilute pesticide wastes.
Solutions of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) with concentrations up to near saturation at pH 3.0 and at 25 °C have been treated with ozone and ozonation catalyzed with Fe2+ and/or UVA light. Direct ozonation yields a slow depollution, while all contaminants are completely removed under UVA irradiation. The highest oxidizing power is achieved when Fe2+ and UVA light are combined, since greater amounts of oxidizing hydroxyl radical are generated and Fe3+ complexes are photodecomposed. The initial mineralization rate is enhanced when herbicide concentration increases and more hydroxyl radicals are produced by the catalyzed ozonation processes. The herbicide decay always follows a pseudo first-order reaction. Reverse-phase chromatography allows the detection and quantification of aromatic intermediates such as 2,4-dichlorophenol, 4,6-dichlororesorcinol and chlorohydroquinone. In all treatments, fast dechlorination reactions take place leading to chloride ion accumulation in the medium. The evolution of generated carboxylic acids such as glycolic, glyoxylic, maleic, fumaric and oxalic has been followed by ion-exclusion chromatography. Only oxalic acid remains stable in the O3 system, being quickly mineralized to CO2 by hydroxyl radicals formed in the O3/UVA one. A high stability of oxalic acid in the O3/Fe2+ system has also been found, since it yields Fe3+-oxalato complexes. These species are photodecarboxylated under UVA irradiation in the O3/Fe2+/UVA system. A possible reaction pathway for 2,4-D mineralization involving all intermediates detected is proposed.
Acute toxicity, accumulation and excretion of four organophosphorous insecticides (diazinon, malathion, fenitrothion and EPN) and their oxidation products (diazinon oxon, malaoxon, fenitrothion oxon and EPN oxon) were studied for killifish (Oryzias latipes). The 48-hr LC50 was 4.4 mg l-1 for diazinon, 1.8 mg l-1 for malathion, 3.5 mg l-1 for fenitrothion, 0.58 mg l-1 for EPN, 0.22 mg l-1 for diazinon oxon, 0.28 mg l-1 for malaoxon, 6.8 mg l-1 for fenitrothion oxon, and 0.16 mg l-1 for EPN oxon. The bioconcentration factors (BCF) of diazinon oxon 0.5, malaoxon 1.1, fenitrothion oxon 2.3 and EPN oxon 11 in the whole body of the fish were much lower than those of diazinon 49, malathion 11, fenitrothion 122 and EPN 1124. As reference data, partition coefficients between n-octanol and water (Pow) were measured for these chemicals. The BCF values of each pesticide and its oxidation product were consistent with the Pow values. The excretion rate constants (k) from the whole body of the fish were 0.12 hr-1 for diazinon, 0.27 hr-1 for malathion, 0.11 hr-1 for fenitrothion, 0.02 hr-1 for EPN, 0.30 hr-1 for fenitrothion oxon and 0.59 hr-1 for EPN oxon. The rates of diazinon oxon and malaoxon could not be measured, but were presumed to be as rapid as or more rapid than those of fenitrothion oxon and EPN oxon. The results suggest that the contamination of fish and other aquatic organisms by the oxidation products in the environment is very low.
The organophosphorus compound pirimiphos methyl was oxidized in water under ozonolysis in the presence of formulating agents. A rapid sample handling procedure was developed based on liquid-solid extraction with nonporous carbon cartridges. This sorbent material allowed recovery of the polar degradation products (DPs). Analysis of oxidized solutions was performed with both GC-ion trap (IT)-MS using either electron impact or chemical ionization as ionization modes and LC-atmospheric pressure ionization (API)-MS using either an ionspray (ISP) or an atmospheric pressure chemical ionization (APCI) interface in order to confirm the presence of DPs. The performances of both technologies were evaluated for structure elucidation and quantitation by using pirimiphos methyl, 2,4-aminophenol and cyanuric acid as external standards of DPs. LC-API-MS techniques allowed the detection of six DPs, of which two were not detected by GC-IT-MS techniques, even after a derivatization procedure with BF3-MeOH reagent. ISP was the most suitable ionization method for identifying the DPs, because sodium or potassium adduct ions were of great help in confirming the molecular mass of unknowns. APCI provided more fragmentation patterns than ISP. However unequivocal identification of all DPs was impossible and only a tentative degradation pathway of pirimiphos methyl in water under ozone is proposed. At the end of the reaction time, DPs accounted for between 70 and 85% of the initial concentration of methyl pirimiphos.
The extensive use of pesticides in agriculture can entail risks for environment and non-target organisms. Hence the need to assess the nature and degree of the risk and at the same time to take preventive measures aimed at minimizing possible damages. The aim of the present study was to investigate the pesticide residues in food and the human body (maternal, young) in the Eastern Romania area, between 1996 and 1997. The organochlorine pesticide residues were analyzed using gas-chromatographic method. DDT-total and HCH-total were determined in 'food' (milk, bread, diets, coffee) sampled in the Eastern Romania area; 'maternal body' (placenta, milk, urine) and 'young body' (serum, urine) from the Iassy district. These pollutants present in all analyzed products involve the necessity of the pollution reduction by a rational use of the pesticides and the continuation of the chemical pollutants determination in the environment elements for cancer prevention and the control of the exposure to environmental carcinogens and their effects.
The photolysis of selected pesticides in aqueous solutions has been investigated. The photolysis produced different intermediate substances, which were also found to be soil and microbial degradation products. The phototransformation in the presence of TiO2 and humic substances leads to a disappearance of these compounds. The reaction rate is dependent on the semiconductor oxide and concentration. Photoproducts were isolated and characterized by different spectroscopic methods. Results from this study indicate that degradation products of isoproturon are more toxic on Daphnia magna than on the parent compound.
Residue levels of organochlorine pesticides have been determined in raw fruits, vegetables and tubers from markets in Nigeria. In the fruits, total HCH, aldrin and total DDT were detected in 77, 38 and 30% of all samples, respectively. In the vegetables, total HCH, HCB, total DDT and aldrin were detected from 95, 53, 50 and 30%, respectively, of all samples. Aldrin + dieldrin, total HCH, and total DDT were detected from 98, 79 and 49%, respectively, of all tuber samples. Other pesticides were below their detection limits. The average levels were generally low and none were above the FAOs maximum residue limits.
In April 1995, the US Geological Survey began a study to determine the occurrence and temporal distribution of 49 pesticides and pesticide metabolites in air and rain samples from an urban and an agricultural sampling site in Mississippi. The study was a joint effort between the National Water-Quality Assessment and the Toxic Substances Programs and was part of a larger study examining the occurrence and temporal distribution of pesticides in air and rain in the Mississippi River basin. Concurrent high-volume air and wet-only deposition samples were collected weekly. The air samplers consisted of a glass-fiber filter to collect particles and tandem polyurethane foam plugs to collect gas-phase pesticides. Every rain and air sample collected from the urban and agricultural sites had detectable levels of multiple pesticides. The magnitude of the total concentration was 5-10 times higher at the agricultural site as compared to the urban site. The pesticide with the highest concentration in rain at both sites was methyl parathion. The pesticide with the highest concentration in the air samples from the agricultural site was also methyl parathion, but from the urban site the highest concentration was diazinon followed closely by chlorpyrifos. More than two decades since p,p'-DDT was banned from use in the United States, p,p'-DDE, a metabolite of p,p'-DDT, was detected in every air sample collected from the agricultural site and in more than half of the air samples from the urban site.
The non-genotoxic effects of two commonly used pesticides, 1,1-bis (p-chlorophenyl)-2,2,2-trichloroethane (DDT) and malathion, and one widely used commercial insect repellent N,N-diethy-m-toluamide (DEET) on gap junction intercellular communication (GJIC) were determined using a rat liver epithelial cell line. Malathion and DDT reversibly inhibited GJIC in a treatment time- and dose-dependent manner at non-cytotoxic doses, whereas, DEET did not inhibit GJIC. Malathion was very reactive with ozone, while DEET and DDT did not react to any appreciable extent with ozone. The mixtures of ozonation products from malathion and DEET did not inhibit GJIC. The mixtures of ozonation by-products formed from DDT inhibited GJIC, but to a lesser extent than did DDT, itself. These results suggest that ozone can effectively remove malathion from solution without forming GJIC-toxic products, but is less effective in eliminating DEET and DDT from solution.
The degradation of carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate), a frequently used carbamate derivative pesticide that is considered a priority pollutant, is carried out in batch reactors by means of single oxidants: ozone, UV radiation and Fenton's reagent; and by the advanced oxidation processes (AOPs) constituted by combinations of ozone plus UV radiation, UV radiation plus H(2)O(2), and UV radiation plus Fenton's reagent (photo-Fenton system). For all these reactions, the apparent pseudo-first-order rate constants are evaluated in order to compare the efficiency of each process. In addition and by means of a competition kinetic model, the rate constants for the reaction of carbofuran with ozone and with hydroxyl radicals are also determined. The improvement in the decomposition levels of carbofuran reached by the combined processes in relation to the single oxidants, due to the generation of the very reactive hydroxyl radicals, is also established in every process. For the oxidant concentrations applied, the most effective process in removing carbofuran was the photo-Fenton system.
The degradation of mono- and dichlorophenylureas under ozone/hydrogen peroxide conditions was investigated in order to establish the effect of the structural parameters. The N-dimethyl phenylureas (mono- and dichloro) appear to differ strongly from the corresponding N-methyl N-methoxy analogues in terms of disappearance of the parent pesticide and evolution of the by-products identified by MS and MS-MS. The degradation rate of the latter is slower by a factor of 2.5 giving rise to additional pathways (hydroxylation of the phenyl ring and carbinolamine intermediate). Experiments with 14C-labelled compounds allow a complete determination of the mass balances obtained after solid-phase-extraction (SPE). This study demonstrates the interest of SPE for reaction monitoring and compares the performances of different types of phases for this purpose used alone or in combination. Mineralisation is also evaluated regarding 14CO2 production and found to contribute up to 20% in the degradation process.
Anodic Fenton treatment (AFT) is a new technology that has several advantages over classic Fenton treatment and electrochemical Fenton treatment. The oxidation of diazinon by AFT using different electrolytes has been investigated. NaCl, KCl and Na2SO4 show similar effects on the extent and rate of oxidation, and the data can be fitted quite well by the AFT kinetics model. Use of NaNO3 as the electrolyte causes low-efficiency electrolysis and a subsequent low oxidation rate for diazinon. The NaCl concentration level in the anodic half-cell and the concentration ratio between the two half-cells is optimized at 0.04M and 4:1 (cathodic/anodic), respectively. The activation energy of diazinon oxidation by anodic Fenton treatment is estimated to be 12.6 +/- 0.6 kJ mol(-1), which is less than half of that for aqueous chlorine treatment. Diazoxon is the intermediary oxidation product. The oxidation of diazinon as a formulated product has also been investigated. Its dissipation kinetics can also be fitted quite well by the AFT model. Compared with the oxidation of pure diazinon, the oxidation rate of formulated diazinon is much lower, an indication that many formulation ingredients compete with diazinon for reaction with the hydroxyl radical.
The degradation of phorate, a highly toxic organic phosphate pesticide, in aqueous solution by photolytic ozonation was studied under various experimental conditions. The rate constants of phorate decomposition and formation of various anions by photolytic ozonation were roughly independent of the solution's pH value. The initial step of the photolytic decomposition of phorate is considered to be the breakage and subsequent oxidation of the P=S double bond on the phorate molecule, followed by isomerization and consequent oxidation of various organic intermediates.
The ozonation of herbicide 2,4-dichlorophoxyacetic acid (2,4-D) was studied and modeled at different initial pH levels and initial concentrations. The degradation rate of 2,4-D was found to increase with the initial pH level and decrease with initial 2,4-D concentration. A two-stage ozonation of 2,4-D was observed, in which the initial stage of ozonation was slightly faster than the second stage due to the higher initial (saturated) ozone concentration; under these circumstances, the direct molecular ozone oxidation was likely to predominate. At the second stage, the indirect radical oxidation became more significant in determining the overall 2,4-D oxidation, and the reaction was more pH-dependent. A mathematic model associated with the analytical solutions consisting of direct and indirect oxidations contributed by the molecular ozone and free radical is proposed. The proposed model is capable of predicting the decay of 2,4-D quantitatively by ozonation at different initial pH levels and initial 2,4-D concentrations.
Column studies were conducted to determine the ability of ozone to degrade aniline and trifluralin in soil. Ozone rapidly degraded aniline from soil under moist soil conditions, 5% (wt). Removal of 77-98% of [UL-14C]-aniline was observed from soil columns (15 ml, i.d. = 2.5 cm), exposed to 0.6% O(3) (wt) at 200 ml/min after 4 min. Initial ozonation products included nitrosobenzene and nitrobenzene, while further oxidation led to CO(2). Ring-labeled-[UL-14C]-trifluralin removal rates were slower, requiring 30 min to achieve removals of 70-97%. Oxidation and cleavage of the N-propyl groups of trifluralin was observed, affording 2,6-dinitro-4-(trifluoromethyl)-aniline, 2,6-dinitro-N-propyl-4-(trifluoromethyl)-benzamine, and 2,6-dinitro-N-propyl-N-acetonyl-4-(trifluoromethyl)-benzamine. Base solutions revealed that trifluralin was similarly oxidized to CO(2), where 72-83% of the activity recovered comprised 14CO(2). Use of ozone-rich water improved contaminant removal in trifluralin-amended soil columns, but did not improve removal in aniline, pentachloroaniline, hexachlorobenzene amended soil columns, suggesting that ozonated water may improve contaminant removal for reactive contaminants of low solubility.
The photocatalytic degradation of the organophosphorus insecticide diazinon in aqueous suspensions has been studied by using titanium dioxide as a photocatalyst. The degradation of the insecticide was a fast process and included the formation of several intermediates that were identified using GC/ion-trap mass spectrometry with EI or CI in positive and negative ionization mode and HPLC/electrospray-QqTOF mass spectrometry. Since primarily hydroxy derivatives were identified in these aqueous suspensions, the mechanism of degradation was probably based on hydroxyl radical attack. The initial oxidative pathways of the degradation of diazinon involved the substitution of sulfur by oxygen on the Pz.dbnd6;S bond, cleavage of the pyrimidine ester bond, and oxidation of the isopropyl group. Exact mass measurements of the derivatives allowed the elemental formula of the molecules to be determined confidently. Similarities to the metabolic pathways occurring in living organisms were observed.
A dynamic system based on the water/air equilibrium at the interface within the length of a microporous tube has been used to determine experimentally the Henry's law constants (HLC) of two pesticides: metolachlor and diazinon. The measurements were conducted over the temperature range 283-301 K. At 293 K, HLCs values are (42.6+/-2.8) x 10(3) (in units of M atm(-1)) for metolachlor and (3.0+/-0.3)x10(3) for diazinon. The obtained data were used to derive the following Arrhenius expressions: HLC=(3.0+/-0.4) x 10(-11) exp((10,200+/-1,000)/T) for metolachlor and (7.2+/-0.5) x 10(-15) exp((11,900+/-700)/T) for diazinon. At a cumulus cloud temperature of 283 K, the fractions of metolachlor and diazinon in the atmospheric aqueous phase are about 57% and 11% respectively. In order to evaluate the impact of a cloud on the atmospheric chemistry of both studied pesticides, we compare also their atmospheric lifetimes under clear sky (tau(gas)), and cloudy conditions (tau(multiphase)). The calculated multiphase lifetimes (in units of hours) are significantly lower than those in gas phase at a cumulus temperature of 283 K (in parentheses): metolachlor, 0.4 (2.9); diazinon, 1.9 (5.0).
Determination of multiresidue of pesticides in vegetable by gas chromatography
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Investigation of organic phosphorus pesticides residue in summer vegetables
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Occurrence of pesticides in rain and air in urban and agricultural area of Mississippi
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Identification photocatalytic degradation products of diazinon on TiO 2 aqueous suspensions using GC/MS/ MS and LC/MS with quadrupole time-of-flight mass spectrometry
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products of diazinon on TiO 2 aqueous suspensions using GC/MS/
MS and LC/MS with quadrupole time-of-flight mass spectrometry.
Journal of American for Mass Spectrometry, 14, 803-817.
Survey of food poisoning by organosphorus pesticide at an employee refectory
- Deng
Determination of multiresidue of pesticides in vegetable by gas chromatography
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Survey of pesticides contaminated vegetable in Xi’an, China
- Ma
Degradation of pesticides by chlorination during water purification. Groundwater contamination, environmental restoration, and diffuse source pollution
- Magara