Dimethoate In Water Research Articles

UV-metal ion synergistic activation of ferrate(VI) for the degradation of dimethoate

The improvement in the degradation efficiency of dimethoate was achieved through the activation of UV light and metal ions. The study found that Fe(VI) was effectively activated by Cu(II), Fe(III), and Fe(II), resulting in an improved removal rate of dimethoate in water, with the activation efficiency of Cu(II) > Fe(III) > Fe(II). Under UV irradiation, the synergistic activation effects of UV-Cu(II) and UV-Fe(III) were most pronounced and positively correlated with light intensity. The mineralization rate of dimethoate by UV-Fe(III)-Fe(VI) reached up to 37 %, significantly outperforming the Cu(II)-Fe(VI) system. The main active species in the Cu(II)-Fe(VI) and Fe(III)-Fe(VI) systems were Cu(III) and Fe(IV)/Fe(V), while those in the UV-Fe(III)-Fe(VI) were ·OH and ·O2- radicals, respectively. In the UV-metal ions activated Fe (VI) system, the main degradation mechanisms of dimethoate were hydrolysis, cleavage, oxidation, and recombination. The impacts of water quality parameters on degradation efficiency were also investigated, finding that Cl- had almost no effect, while SO42- had a slight repression effect, and HCO3-, CO32- and NO2- exhibited strong inhibitory effects. Finally, the promising application of the UV-metal ion-Fe(VI) system in actual water environments was proposed, achieving effective removal with minimal environmental risks.

Upotreba sondi cink dioksida za praćenje biološke i hemijske kontaminacije vode u civilne i vojne svrhe

Mainly organic pollutants, and their random wide application threatens human health and ecosystems. It is clear that detoxifying toxic insecticides from aquatic systems remains a global priority. In this study, a zinc oxide nanocatalyst with suitable properties was synthesized to achieve complete degradation of some insecticides from aqueous media. ZnO catalyst was used in normal and nano size as part of an advanced oxidation process in the presence of H2O2 and UV rays. The complete detoxification of the tested pesticides after treatment with the most effective process (ZnO(s)/H2O2/UV) was then investigated by biochemical treatment research. The effect of ZnO water treatment was also investigated. Interestingly, this study reported that the degradation rates of the investigated insecticides were faster using nano-sized ZnO catalysts than plain ZnO catalysts as well as zinc dioxide probes. In this sense, complete decomposition of the investigated insecticides (100%) in the ZnO(s)/H2O2/UV system was achieved after 320 min of irradiation. Water treatment with zinc oxide nanocatalyst improved the quality of water parameters. Together, the advanced oxidation processes using ZnO nanocatalyst can be considered as a promising treatment technology for the complete detoxification of methomyl and dimethoate in water. However, further research is warranted to identify potential breakdown products.

Life-sustaining of H+ in S(IV)/Fe(VI) system for efficient removal of dimethoate in water: Active species identification and mechanism

The present study developed a prolonged oxidizable sulfur(IV)/ferrate(VI) system for the generation of hydroxyl radical (OH) and sulfate radical (SO4−) within 120 min, and proposed a reaction mechanism. In the presence of H+ in solution, the S(IV)/Fe(IV) system provided excellent oxidation performance of refractory organics O,O-dimethyl-S-methylcarbamoyl methyl phosphorothioate (dimethoate, a widely used organophosphorus pesticide) within 120 min. The degradation efficiency of dimethoate in the bisulfite/Fe(VI) system (e.g., 90.06% dimethoate) was higher than that in the sulfite/Fe(VI) system (e.g., 51.03% dimethoate), while Fe(VI) alone degraded 27.81% of dimethoate. In the S(IV)/Fe(VI) system, the active species consisted of Fe(VI) (including the highly-reactive iron-based intermediate species, i.e. Fe(V) and Fe(IV)), OH and SO4−, with OH being identified as the main active species, contributing more than half of the total. The degradation mechanism of dimethoate in the S(IV)/Fe(VI) system mainly included the cleavage of the S-P bond, C-S bond and the oxidation of the P = S bond. Two plausible degradation pathways were proposed based on the detected transformation products. Dimethoate could be efficiently degraded when the [bisulfite]/[Fe(VI)] molar ratio was 4:1 with a low Fe(VI) dosage (218 µM), the changes in HA and HCO3− concentrations affected the transformation of dimethoate, the presence of Cl−, SO42− and NO3− had a negligible effect, and the S(IV)/Fe(VI) system performed well in real waters. The S(IV)/Fe(VI) system has excellent oxidation performance for the removal of organic pollutants in water, with a final pH (pH = 6.6) close to neutral and ultimate products of SO42− and Fe(OH)3, which has great potential for engineering applications.

Advanced Oxidation Processes Using Zinc Oxide Nanocatalyst for Detoxification of Some Highly Toxic Insecticides in an Aquatic System Combined With Improving Water Quality Parameters

Pesticides are among the major organic pollutants, and their random extensive applications threaten human health and ecosystems. Clearly, detoxification of toxic insecticides from the aquatic system remains a global priority. In the present study, a zinc oxide nanocatalyst was synthesized with suitable properties to achieve complete degradation of some insecticides (dimethoate and methomyl) from aqueous media. The ZnO catalyst was used in normal and in nano-size as a part of an advanced oxidation process in the presence of H2O2 and UV rays. The complete detoxification of the tested pesticides after treatment with the most effective process (ZnO(s)/H2O2/UV) was then examined by exploring the biochemical and histopathological changes in the liver and kidneys of treated rats compared to the control. The effect of water treatment by ZnO (nano)/H2O2/UV on the water quality parameters of treated water was also investigated. Interestingly, the present study reported that the degradation rates of the investigated insecticides were faster using the nano-sized ZnO catalyst than the regular ZnO catalyst. In this respect, complete decomposition of the tested insecticides (100%) under the ZnO(s)/H2O2/UV system was achieved after 320 min of irradiation. The half-lives of the tested insecticides under ZnO(c)/H2O2/UV were 43.86 and 36.28 for dimethoate and methomyl, respectively, while under the ZnO(c)/H2O2/UV system, the half-live values were 27.72 and 19.52 min for dimethoate and methomyl, respectively. On the other hand, there were no significant changes in the biochemical and histological parameters of rats treated with remediated water when compared to the control group. The treatment of water by zinc oxide nanocatalyst improved the quality of water parameters. Collectively, advanced oxidation processes using ZnO nanocatalyst can be considered as a promising treatment technology for the complete detoxification of methomyl and dimethoate in water. However, further research is warranted for the identification of the potential breakdown products.

Photocatalytic Detoxification of Some Insecticides in Aqueous Media Using TiO2 Nanocatalyst.

The present study was performed to fabricate a titanium dioxide (TiO2) nanocatalyst with proper characteristics for the removal of some insecticides (dimethoate and methomyl) from aqueous media. A TiO2 catalyst of regular (TiO2—commercial—/H2O2/UV) or nano (TiO2—synthesized—/H2O2/UV) size was employed as an advanced oxidation process by combining it with H2O2 under light. Moreover, the total detoxification of insecticides after treatment with the most effective system (TiO2(s)/H2O2/UV) was also investigated through exploring the biochemical alterations and histopathological changes in the liver and kidneys of the treated rats. Interestingly, the present study reported that degradation rates of the examined insecticides were faster using the TiO2 catalyst of nano size. Complete degradation of the tested insecticides (100%) was achieved under the TiO2(s)/H2O2/UV system after 320 min of irradiation. The half-life values of the tested insecticides under H2O2/TiO2(c)/UV were 43.86 and 36.28 for dimethoate and methomyl, respectively, whereas under the H2O2/TiO2(c)/UV system, the half-life values were 27.72 and 19.52 min for dimethoate and methomyl, respectively. On the other hand, no significant changes were observed in the biochemical and histopathological parameters of rats administrated with water treated with TiO2(s)/H2O2/UV compared to the control, indicating low toxicity of the TiO2 nanocatalyst-. Altogether, the advanced oxidation processes using TiO2 nanocatalyst can be considered as a promising and effective remediation technology for the complete detoxification of methomyl and dimethoate in water. However, further future research is needed to identify the possible breakdown products and to verify the safety of the used nanomaterials.

Chlorpyrifos and Dimethoate in Water and Sediments of Agricultural Drainage Ditches in Northern Sinaloa, Mexico.

In northern Sinaloa state, Mexico, little is known on organophosphate pesticide transport and fate in agricultural drainage systems. Spatial and temporal variation of chlorpyrifos and dimethoate was assessed in two agricultural drainage ditches (Buenaventura and Burrión) and risk for aquatic life was estimated. Analysis was made by high performance liquid chromatography and risk estimates were determined following international reference frameworks. In water, the highest chlorpyrifos concentration in the Buenaventura ditch was 5.49µgL-1, and 3.43µg L-1 in the Burrión ditch. Dimethoate was quantified only once in both ditches (0.44µgL-1 and 0.49µgL-1). In sediment, chlorpyrifos was quantified only in the Burrión ditch (242µgkg-1). Chlorpyrifos concentrations surpassed water and sediment quality criteria, representing a hazard for environmental and human health, as both ditches discharge into the Gulf of California and are used for capture of commercial species such as the grey mullet (Mugil cephalus) and cauque prawn (Macrobrachium americanum).

Assessment of the effects of atrazine, dichlorodiphenyltrichloroethane, and dimethoate on freshwater fish (Oreochromis mossambicus): a case study of the A2 farmlands in Chiredzi, in the southeastern part of Zimbabwe.

A study was carried out to assess the levels and effects of atrazine, dimethoate, and dichlorodiphenyltrichloroethane on freshwater fish (Oreochromis mossambicus). Water and fish were sampled once from a dam within the Hippo Valley A2 farmlands in Chiredzi, in the southeastern part of Zimbabwe. The samples were screened for atrazine, dimethoate, and dichlorodiphenyltrichloroethane (DDT), the pesticides commonly used in the region. Atrazine and dimethoate are pesticides commonly used in the control of weeds and pests in the agricultural production of sugarcane in Hippo Valley, Chiredzi region. The effects of the pesticides on biochemical endpoints of the sampled fish were determined. The analyzed biochemical end parameters were superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase activities in liver and white muscle fish extracts. Dichlorodiphenyltrichloroethane was observed in water and fish muscle tissue at concentrations of 131.3 μg/l and 171.7 μg/kg, respectively, while atrazine was detected at concentrations of 6.15 μg/l and 142.0 μg/kg in water and fish muscle tissue, respectively. The observed concentrations of atrazine and DDT in water samples were above the limits permissible by the World Health Organization in drinking water. Dimethoate was found in concentrations of 4.21 μg/l and 1.30 μg/kg in water and fish muscle tissue respectively. The observed concentration of dimethoate in water was below the acceptable limit set by the Guidelines for Canadian Drinking Water. Antioxidant enzyme activities were increased significantly (p < 0.05) in fish exposed to water from Hippo Valley, Chiredzi, when compared with the controls. The enhanced activities of the studied antioxidant enzyme system were attributed to exposure to pollutants in the water body. Alterations of the biochemical integrity of fish indicate negative effects of the pesticides on the well-being of fish and undoubtedly other aquatic biota as well.

A simple spectroscopic method to determine dimethoate in water samples by complex formation

A simple and rapid method for the determination of dimethoate in water was developed based on the monitoring of the complex formation between bis 5-phenyldipyrrinate of nickel (II) and the herbicide dimethoate. The method showed a short response time (10 s), high selectivity (very low interference from other sulfate and salts), high sensitivity (limit of detection (LOD) 0.45 µM, limit of quantitation (LOQ) of 1.39 µM), and a Kd of 2.4 µM. Stoichiometry experiments showed that complex formation occurred with a 1:1 relation. The method was applied to different environmental water samples such as lagoon, stream, urban, and groundwater samples. The results indicated that independently from the water source, the method exhibited high precision (0.25–2.47% variation coefficient) and accuracy (84.42–115.68% recovery). In addition, the method was also tested using an effluent from a wastewater treatment plant from Mexico; however, the results indicated that the presence of organic matter had a pronounced effect on the detection.

Non-thermal plasma needle as an effective tool in dimethoate removal from water

Intensive use of pesticides requires innovative approaches for their removal from the environment. Here we report the method for degradation of dimethoate in water using non-thermal plasma needle and analyze kinetics of dimethoate removal and possible degradation pathways. The effects of dimethoate initial concentration, plasma treatment time, Argon flow rate and the presence of radical promoters on the effectiveness of proposed method are evaluated. With argon flow rate of 0.5 slm (standard litres per minute) 1 × 10−4 M dimethoate can be removed within 30 min of treatment. Using UPLC analysis it was confirmed that one of the decomposition products is dimethoate oxo-analogue omethoate, which is in fact more toxic than dimethoate. However, the overall toxicity of contaminated water was reduced upon the treatment. The addition of H2O2 as a free radical promoter enhances dimethoate removal, while K2S2O8 results with selective conversion to omethoate. Using mass spectrometry in combination with the theoretical calculations, possible degradation pathways were proposed. The feasibility of the proposed method for dimethoate degradation in real water samples is confirmed. The proposed method is demonstrated as a highly effective approach for dimethoate removal without significant accumulation of undesirable toxic products and secondary waste.

Gold-nanoparticle-based fluorescent “turn-on” sensor for selective and sensitive detection of dimethoate

A simple approach to fabricate a highly selective and sensitive dimethoate probe was developed based on Rhodamine B (RB)-functionalized gold nanoparticles (AuNPs). The quenching of RB fluorescence in the presence of AuNPs in the solution, mediated by fluorescence resonance energy transfer, was observed. In the presence of dimethoate, the fluorescence intensity of the RB-AuNP solution is gradually recovered when dimethoate molecules displace RB molecules on the surface of the AuNPs, which significantly increased the fluorescence intensity of RB. Fluorescence is proportional to the dimethoate concentration in the range of 0.005–1.0 ppm (R2 = 0.989), and the LOD was 0.004 ppm. The recoveries of dimethoate in water and fruit samples were 86–116% with a good RSD (< 9.3%). Because of its high sensitivity, excellent selectivity, and convenient fabrication process, this method is a promising candidate for dimethoate screening.

Electrochemical biomimetic sensor based on oxime group-functionalized gold nanoparticles and nitrogen-doped graphene composites for highly selective and sensitive dimethoate determination

A novel, sensitive, and selective electrochemical sensor based on oxime-functionalized gold nanoparticles (AuNPs) and nitrogen-doped graphene (NG) composites (NG/AuNPs) was developed for the direct electrochemical detection of dimethoate, a non-electroactive organophosphorus pesticide (OP). 2-(4-Mercaptobutoxy)-1-naphthaldehyde oxime (MNO), a new organic molecule containing –SH and oxime synthesized by our group, was decorated onto electrodes through the S–Au bond between –SH of MNO and AuNPs. NG/AuNPs were modified on the electrode to provide acting sites for MNO and to amplify current response. The results indicated that the reduction current of MNO was increased, and the selectivity, sensitivity, and stability of the sensor were improved. Dimethoate was detected by using MNO as an electroactive probe through the nucleophilic substitution between oxime and dimethoate. Under optimal conditions, the sensor displayed a linear range from 1 × 10−12 to 4 × 10−8 M with a low detection limit of 8.7 × 10−13 M (S/N = 3). Results indicated that the sensor was successfully applied to detect dimethoate in water, tomato, and orange samples. Interference study analyses were investigated using the prepared electrode, which exhibited an acceptable result.

Application of dielectric barrier discharge plasma for degradation and pathways of dimethoate in aqueous solution

Increasing concerns on environmental water quality have led to the development of effective techniques to remove or decompose water pollutants for health purposes. This paper reported dielectric barrier discharge (DBD) plasma-induced degradation and effects of degradation parameters and degradation pathways of dimethoate in aqueous solution. DBD parameters including discharge power and air-gap distance, dimethoate initial concentration, and radical intervention with radical promoters or scavenger were investigated for their effects on the degradation efficiency by determination of the remaining concentration of dimethoate in the treated solution using HPLC. In addition, identification of intermediates and products were explored using GC–MS, UV–VIS spectrometer and FT-IR techniques. The corresponding DBD plasma degradation pathways of dimethoate were also proposed. The result shows that the degradation efficiency is greater than 96% at the optimum degradation parameters: dimethoate initial concentration=20mgL−1, applied power=85W, air-gap distance=5mm, and treatment time=7min. The degradation efficiency is clearly accelerated by adding radical promoters, but sharply decelerated in the presence of radical scavenger. These results have revealed a novel effective method for dimethoate degradation, demonstrated hydroxyl radical (OH) playing an important role in the degradation pathways, and suggested potential application of DBD plasma for degradation of dimethoate in water.

Determination of trace dimethoate in milk and river water by kinetic spectrophotometry using malachite green and potassium periodate

In the present study, a new sensitive and simple kinetic-spectrophotometric method for the determination of the insecticide dimethoate [O,O-dimethyl-S-(N-methyl-carbomoylmethyl)-phosphoro-dithioate] is developed. The method is based on the inhibition effect of dimethoate on the oxidation of malachite green (MG) by potassium periodate (KIO4) in the presence of Mn(II) ions. Inhibition kinetics of this catalytic reaction was investigated in the presence of dimethoate and the possibility of its analytical application was evaluated. The important variables that affected the reaction rate were investigated and the optimum conditions giving maximum sensitivity were established. Dimethoate was determined with linear calibration graph in the interval from 4.58 to 41.22 μg/mL. The optimized conditions yielded a theoretical detection limit of 1.24 μg/mL based on the 3S b criterion. The RSDs of the method (n = 5) were 1.2–4.9% for the concentration interval of dimethoate from 4.58 to 41.22 μg/mL. The reaction was monitored spectrophotometrically by measuring the change in absorbance over time at 615 nm. The method was applied to the determination of dimethoate in waters and milk, and was compared with the spectrophotometric method. The quantitive method developed on the basis of inhibition kinetics is practical, fast and economical. For this reason, it is open for new application fields.

Feasibility research on rapid detection of dimethoate in water by near-infrared spectroscopy

Near infrared (NIR) spectroscopy combined with chemometrics is used for the rapid detection of dimethoate in water without sample preparation. In order to overcome the non-linear phenomenon least-squared support vector machines (LS-SVM) is utilized. Classification accuracy of the training set and the testing set were 100% when two parameters, γ and σ2 (270.191 and 29.60, respectively), were chosen by the Simplex optimizing algorithm. The entire operating procedure, which takes less than 2 minutes per sample to complete, is rapid, convenient and environmentally acceptable. It shows potential for the rapid screening of dimethoate in water samples.

Multi-Residue Analysis of Some Polar Pesticides in Water Samples with SPE and LC–MS–MS

In the present study a multi-residue analytical method was developed for monitoring some polar pesticides such as acephate, methamidophos, carbofuran, isoproturon, dimethoate in water with SPE (solid-phase extraction) and LC–MS–MS. Acetochlor was taken as surrogate, and alachlor as internal standard. SPE with different types of columns was compared with LLE (liquid-liquid extraction). Further, the breakthrough volume for different pesticides was determined. The results showed that the selected pesticides can be determined very sensitively with LC–MS–MS. The minimum detectable quantity (MDQ) for each pesticide was about 1.0 ng. To date, SPE cartridge studies showed that the Oasis HLB cartridges were suitable for further studies. However, for Oasis HLB cartridge, different pesticide showed different breakthrough volume. The results showed that for acephate and methamidophos, the breakthrough volume was about 30 mL of water sample, much less than the breakthrough volume of other pesticides studied. Because of the higher vapor pressure and higher Henry's constant of methamidophos, dimethoate and carbofuran, much attention should be paid on their losses in the evaporation step of the experiment. This analytical method can be applied to determine pesticide contamination in environmental water samples.

Analysis of pesticide residues by on‐line reversed‐phase liquid chromatography–gas chromatography in the oil from olives grown in an experimental plot

AbstractThis paper describes the use of a fully automated on‐line reversed‐phase liquid chromatography–gas chromatography (RPLC‐GC) method for the determination of four organophosphorus pesticides (dimethoate, methidathion, chlorpyriphos and fenitrothion) in olive oil. These pesticides are among those more extensively used to control pests and disease in olive trees. Various treatments with these pesticides, at various doses and stages of olive ripening, were carried out in an olive grove. The olives were harvested in mid‐December and immediately processed into oil in the laboratory. Fully automated analyses by on‐line RPLC‐GC using the through oven transfer adsorption desorption (TOTAD) interface was carried out without any kind of sample pretreatment other than a simple filtration step. A statistical analysis was performed. No dimethoate remained in the oil owing to the high solubility of dimethoate in water. Differences between the other three pesticide residues were significant. Chlorpyriphos provided the lowest residues, followed by fenitrothion and methidathion. Treatments carried out in June did not leave residues in the oil, but all the treatments carried out in October and December led to pesticide residues that were higher than the limits of detection. Copyright © 2005 Society of Chemical Industry

Photocatalytic oxidation of organic pollutants in water

The primary photo-oxidation at pollutant level concentration of dodecylbenzene sulfonate (DBS), azynphos-methyl and dimethoate in water has been studied in homogeneous and heterogeneous media by using a 400 W lamp with a solar spectral distribution, and TiO 2 and FeCl 3 as catalysts. Two different geometries of differential batch-recycled reactors were used: first, a concentric tubular reactor with the lamp placed at the tube axis and second, a flow through parallel-plate reactor. An incidence radial model and a linear source spherical emission (LSSE) model with a Monte-Carlo approach to account for scattering of light have been used for the light intensity distribution. Data showed a molar concentration reduction of 30% for DBS in 150 min with light and TiO 2. When FeCl 3 was used as photocatalyst, concentration of DBS was reduced by 70%. Similar behavior found for azynphos-methyl was reduced to 85% in 20 min after irradiation with FeCl 3; 100% in 20 min with TiO 2 and 100% in 2 min with TiO 2 and FeCl 3. Approximately the same performance obtained for dimethoate was completely oxidized in 20 min after irradiation of slurry solution of TiO 2 with FeCl 3. From these data kinetic equations were obtained by assuming a free-radical mechanism for oxidation of hydrocarbons. Pollutants present no activity to solar light, but when FeCl 3 or TiO 2 were used, pollutants were decomposed; being the value of kinetic constant of order 10 4 cm 2/einst. When the solution was irradiated with a FeCl 3 and TiO 2 together, the rate increased about 10 times more. Also, deactivation of catalyst was studied by X-ray diffraction, TG and DTA methods.

Coating combined with dimethoate as a quarantine treatment against fruit flies (Diptera: Tephritidae)

Abstract Grapefruits infested with Caribbean fruit fly, Anastrepha suspensa (Loew), larvae were coated with Nature Seal containing 1.5% hydroxypropyl cellulose or Sta-Fresh 360 HS with or without 300 ppm dimethoate. Another treatment was dipped in 300 ppm dimethoate in water, and a final group of infested grapefruits remained untreated (control). Coating or dimethoate alone reduced the number of Caribbean fruit fly larvae emerging from grapefruits significantly (95% confidence level). The combination of coating plus dimethoate yielded 93–98.7% less larvae than either coating or dimethoate alone. Dimethoate residues in the pulp of grapefruits coated with Sta-Fresh 360 HS plus dimethoate (

Determination of dimethoate in water by cathodic stripping square‐wave voltammetry

AbstractThis article describes the direct‐determination of the pesticide dimethoate In river water in an alkalin media and accumulaton medium through cathodic stripping voltammetry. By employing an alkaline potential of 30 mV, reduction peak appears at −0.7 V. The detection limit is 1 ng ml−1.

Extractive spectrophotometric determination of dimethoate with molybdate and Methylene Blue by a flotation–dissolution method

A sensitive extraction spectrophotometric method based on flotation–dissolution is described for the determination of trace levels of the organophosphorus pesticide dimethoate. Dimethoate is converted into a molybdophospho complex by reaction with ammonium molybdate in sulfuric acid medium. The complex floating on the interface of the aqueous and organic layers along with Methylene Blue as an ion associate is separated and dissolved in acetone. The colour system obeys Beer's law in the range 0.02–0.16 µg ml–1 of dimethoate. The molar absorptivities of the system calculated in terms of phosphorus and dimethoate are 1.5 × 105(±100) l mol–1 cm–1 and 1.08 × 106(±100) l mol–1 cm–1, respectively. The standard deviation and relative standard deviation were 0.006 µg ml–1 and 3.2%, respectively. The method was satisfactorily applied to the determination of dimethoate in water, soil and plant materials.