Pesticide Residues In Lettuce Research Articles

Efficacy of some washing solutions for removal of pesticide residues in lettuce

BackgroundWhen previous studies were examined, it was reported that a wide variety of pesticide residues were detected in lettuce (Bakırcı et al. in Food Chem 160:379–392, 2014; Balkan and Yılmaz in Food Chem 384:132516, 2022; Qin et al. in Food Res Int 72:161–167, 2015; Selim et al. in Res J Environ Sci 5:248–258, 2011). In addition, pesticide-contaminated lettuce poses a risk to consumers as it is a fresh food that is eaten raw. Therefore, pesticide removal processes must be applied before consumption. Some pesticide removal process, such as storage and heat treatment cannot be applied to lettuce because of unshelled, no long shelf life and consuming as fresh. Different practical methods are needed for the removal of pesticides process. The recommendations of suitable methods for cleaning salad materials in ready-to-eat sector, hotels, restaurants and homes are very important. It is important to reduce pesticide residues in vegetables and fruits that are consumed raw by washing them with non-toxic solutions. These approaches aim to protect public health. The study conducted in 2021 determined the effect of various washing treatments. For this purpose, before the washing trials, QuEChERS method was validated for determination of 7 pesticides in lettuce, by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Lettuce plants were grown in the greenhouse for the study. Lettuces were brought to the laboratory 24 h after pesticides were applied in the greenhouse. The samples were kept in 2 L washing solution for pesticide analysis.ResultsThe processing factor values of all washing applications were found below 1. This result shows that the residue level was reduced by washing solutions. Among the washing solution treatments, the rice vinegar washing solution was found to be most effective in reducing the pesticide residues which was due to the high degree in the pesticide degradation. Washing with filtered rice water also exhibited equivalent reduction capability similar to rice vinegar.ConclusionsThe effectiveness of washing solutions was different for boscalid, deltamethrin, fluopcolide, fluopyram, pyrimethanil, pyraclostrobin and sulfoxaflor. However, when the average removal of these pesticides was evaluated, the most effective solutions were rice vinegar, filtered rice water, carbonated water, NaCl + grape vinegar, hot tap water (40 °C), grape vinegar (6% acetic acid), grape vinegar + water, cold tap water (20 °C), lemon juice, baking soda water, grape vinegar (8% acetic acid), filtered mint water and grape vinegar (4% acetic acid), respectively. It was concluded that some of the solutions used in this study can significantly reduce exposure to pesticides for consumers.

Human health risk assessment of pesticides in lettuce and spinach grown in urban backyard garden soils

Pesticide residues in lettuce and spinach could be a serious human health concern since the average per capita consumption per day of leafy salad vegetables is ∼60 g. Here, we determined the leftover residues (LoR) of dimethoate, 2,4-D, glyphosate, and chlorothalonil in lettuce and spinach grown in three urban backyard soils to assess their potential human health hazards. Pesticide residues were extracted by QuEChERS method and quantified through LC-MS and LC-DAD. In most cases, residue levels in the vegetable samples were above the EU-MRLs. Soil organic carbon, silt, oxides of iron and aluminium negatively correlated (P < 0.05) with LoR of the pesticides while LoR positively correlated (P < 0.05) with contents of sand and clay, and pH. The estimated short-term intake (ESTI) values (mg kg1 day1) for dimethoate, 2,4-D, glyphosate and chlorothalonil even at recommended doses in case of lettuce and spinach were 0.003–9.90 × 103 and 0.005–37.10 × 103 for adults and children, respectively, whereas the corresponding estimated daily intake (EDI) values were 0.007–9.58 × 103 and 0.03–35.90 × 103. Accordingly, the calculated values of non-cancer acute health hazard (aHI <100%) and hazard quotient (HQ <1) indicated that consumption of salad vegetables grown in soils spiked with pesticides at doses recommended in agriculture does not pose human health risks. On the other hand, both lettuce and spinach grown in soils at ten-fold higher concentrations of dimethoate or chlorothalonil exceeded the threshold limit of aHI (>100%) for children and HQ > 1 for both children and adults, suggesting their potential acute and chronic health hazards. The present study, for the first time, provides health awareness about the consumption of pesticide-contaminated leafy vegetables grown in urban backyard garden soils.

Safety of foods sold in street fairs: analysis of pesticide residues in lettuce (Lactuca sativa L.)

Pesticides are chemical contaminants that can be found in food. Those with the greatest residual representation include insecticides, fungicides, and herbicides. The objective of this study was to analyze the presence of pesticide residues in lettuce (Lactuca sativa L.) sold at street fairs. This was a quantitative, cross-sectional study, carried out in street fairs in Chapecó, state of Santa Catarina, with producers of fresh vegetables, and consumers, and also analyzed pesticide residues in lettuce from conventional and organic cultivation. Data were collected using a semistructured questionnaire, administered to all producers, and a sample of consumers. Pesticide residues were analyzed in lettuce as it is the most purchased food by consumers. Pesticides surveyed included azoxystrobin, deltamethrin, imidacloprid, and glyphosate, as they are the most frequently applied on farms, and in cultivation of vegetables. Of the 67 vendors active in the seven street fairs, 30 were vegetable and fruit producers, and of these, 17 were conventional producers and 13 were organic farmers. The analysis of pesticide residues in lettuce from conventional production showed residues of azoxystrobin and imidacloprid, but below the maximum residue limits allowed by Anvisa. In samples of organic lettuce, residues of the analyzed pesticides were not detected. From the analysis of residues in lettuce, it is inferred that the food is safe in terms of the pesticides analyzed and that municipal public policies should prioritize systematic monitoring to ensure food safety and encourage the production of organic food.

Application of deep brief network in transmission spectroscopy detection of pesticide residues in lettuce leaves

AbstractTo realize the quick, nondestructive detection of pesticide residues in lettuce leaves, a new method based on deep brief network (DBN) combined with near‐infrared transmission spectroscopy, was studied in this article. Two kinds of pesticide residues (fenvalerate and triazoline) and distilled water were sprayed on the surface of lettuce leaves, respectively. In addition, near infrared transmission spectroscopy was used for collecting spectral data of 240 lettuce samples. Furthermore, Savitzky–Golay combined with multiplicative scatter correction was used to denoise the raw spectral data. Then, after preprocessing spectral data, DBN was used to extract features and identify kinds of pesticide residues in lettuce leaves. Moreover，successive projection algorithm (SPA) was used to select characteristic wavelengths. After all, support vector machine (SVM), PLS‐DA, and k‐nearest neighbor were carried out to establish classification models based on full spectral data, data extracted by DBN and data extracted by SPA. Consequently, DBN–SVM performed best and the accuracy of training set and test set reached 98.89 and 95.00%, respectively. Hence, the method of near infrared transmission spectroscopy combined with DBN–SVM is practical for the qualitative analysis of pesticide residues in lettuce leaves.Practical applicationsUsing near infrared spectroscopy could detect the kinds of pesticide residues in lettuce leaves quickly and effectively. A new method involving deep brief network (DBN) was proposed to extract the features of spectral data. Results in this study showed that the DBN is feasible and effective for building classification models of different pesticide residues.

Study on pesticide residues classification of lettuce leaves based on polarization spectroscopy

AbstractIn order to effectively implement the rapid and nondestructive testing of pesticide residues in lettuce leaves, polarization spectral detection technology was used in this article. There were 90 pieces of lettuce leaves from five different groups, as well as a total of 450 samples of lettuce were used to collect polarization spectral information. CARS, IRIV, and SPA were used to obtain optimal wavelengths. BP neural network, KNN, and SVM were used to establish classification models. The results showed that the significance of these parameters from primary factor to secondary factor were incident zenith angle A, detector polarization angle D, detecting zenith angle B, and sample stage azimuth E, respectively. Besides, optimal level of A, B, D, and E were 60°, 45°, 30°, and 270°, respectively. Furthermore, the best classification model different kinds of pesticide residues in lettuce leaves was CARS‐SVM model, with calibration identification rate of 100%, prediction identification rate of 97.78%. It confirms that polarization spectral detection technology is a feasible and effective method for classifying different pesticide residues in lettuce leaves.Practical applicationsIt is of great significance to understand the effects of pesticide residues on the biological structure and to reveal new biological functions and mechanisms of action. In order to effectively implement the rapid and nondestructive testing of pesticide residues in lettuce leaves, polarization spectral detection technology was used in this article. In addition, the order and superior level of polarization spectral factor were obtained through the calculation of the range using orthogonal test. It confirms that the polarization spectra is a feasible and effective method for discriminating different pesticide residues in lettuce leaves.

Identification of pesticide residues in lettuce leaves based on near infrared transmission spectroscopy

AbstractTo explore the nondestructive and accurate qualitative detection method of pesticide residues in vegetables, lettuce leaves were taken as carrier and pesticides (fenvalerate and chlorpyrifos) were taken as research object. The near infrared spectral data of lettuce leaves was collected by using near infrared spectrometer NIRez (950–1,650 nm), then it was preprocessed by SNV algorithm and SG‐SNV combination, respectively. The successive projections algorithm (SPA), competitive adaptive reweighted sampling (CARS), iteratively retaining informative variables (IRIV), and combination of two of them were used to select characteristic wavelengths from the preprocessed spectral data, respectively. In this study, support vector machine (SVM) was used to classify pesticide residues in lettuce leaves. Because the classification performance of SVM was influenced by parameters c (penalty coefficient) and g (kernel function parameter), so the parameters c and g of SVM were optimized by gravitational search algorithm (GSA). Finally, identification models were built on the full wavelengths and the selected characteristic wavelengths, respectively. Final result showed that CARS‐IRIV‐GSA‐SVM model had the best performance, and the classification accuracy of training set and predication set reached 100 and 98.33%. Therefore, near infrared transmission spectroscopy can be applied to the qualitative detection of pesticide residues in lettuce leaves.Practical applicationsLettuce leaves can be eaten raw, but pesticide residues in lettuce leaves are likely to do harm to human health. Near infrared transmission spectroscopy, a fast and nondestructive technology, can be used to detect pesticide residues in lettuce leaves. Furthermore, the small NIR spectrometer used in this study can also provide some idea for the production of portable pesticide residue detector. This study demonstrated that near infrared transmission spectroscopy can be applied to the qualitative detection of pesticide residues in lettuce leaves.

Discrimination of pesticide residues in lettuce based on chemical molecular structure coupled with wavelet transform and near infrared hyperspectra

AbstractTo facilitate more quickly and effectively detect the types of pesticide residues on the surface of lettuce, a method involving the chemical molecular structure coupled with wavelet transform (CMS‐WT) was proposed to extract the characteristic wavelength. Five different kinds of pesticide residues were sprayed on the surface of lettuce, respectively, dimethoate, acephate, phoxim, dichlorvos, avermectin (the ratio of pesticides and water were 1:1000). In addition, the near infrared hyperspectral image information of 200 samples in five different kinds of pesticides residue in lettuce were achieved by the NIR hyperspectral imaging system (870–1780 nm). The region of interest (ROI) in hyperspectral image of samples was selected to get the near infrared spectral data by the software of ENVI. Furthermore, CMS‐WT was used to extract the most influential wavelengths. Four characteristic intervals were extracted by comparing the different of pesticides in chemical molecular structures, respectively, 875—1050 nm, 1050—1250 nm, 1350—1550 nm, 1650—1780 nm. Further, the best combination of eight features were selected according to the reorder of the size of the singular value by wavelet transform algorithm using db6 as wavelet basis function, respectively, 919.18, 944.25, 972.25, 1194.20, 1363.81, 1426.69, 1673.29, 1680.74 nm. Finally, SVM model was established according to the extracted characteristic spectral data. The results showed that the calibration and prediction accuracy of SVM model established by the best combination of eight features were all achieved 100%. It confirms that the CMS‐WT feature extraction algorithm is feasible and effective for building models of different pesticide residues in lettuce.Practical applicationsWell understanding the effect of pesticide residues to biological structure is very important for revelation of novel biological function and mechanism of action of the protein. To facilitate more quickly and effectively detect the types of pesticide residues on the surface of lettuce, a method involving the chemical molecular structure coupled with wavelet transform (CMS‐WT) was proposed to extract the characteristic wavelength in this article. It confirms that the CMS‐WT feature extraction algorithm is feasible and effective for building models of different pesticide residues in lettuce.

Effect of Irrigating with Slightly Acidic Electrolyzed Water on LettucePhotosynthesis under Mild Water Stress

Abstract. To investigate if slightly acidic electrolyzed water (SAEW) can alleviate mild water stress on plants, we compared the influence of irrigating with SAEW and tap water on growth, chlorophyll content, and photosynthetic characteristics in lettuce (Lactuca sativa L. cv. Italy lettuce) under mild water stress. In this study, lettuce was irrigated with SAEW and tap water at different times. The available chlorine concentration, pH, and oxidation-reduction potential (ORP) of SAEW were 27.75 mg/L, 5.0 and 819 mV, respectively. Both SAEW treatments (long time watering before water stress and re-watering after water stress) showed increases in stem diameter, root length, and biomass accumulation in lettuce when compared with tap water treatments, which meant that inhibition in plant growth was greatly alleviated. Besides, lettuce treated with SAEW maintained a relatively high gas exchange and significantly increased water use efficiency (WUE), showing the better adaptation to water stress. The quality of lettuce was also investigated, and the vitamin C (VC) content in lettuce was not evidently different between these two treatments. Therefore, irrigation with SAEW on lettuce may enhance the photosynthetic efficiency and alleviate the impact of water stress on lettuce growth without destroying VC content of lettuce. Taking the disinfection effect of SAEW into consideration, this work provided a feasible way to lower the risks of pesticide residues in lettuce and alleviate the water stress at the same time.

Determination of Multi-Class Pesticide Residues in Lettuce and Cucumber by GC-MSD and the Degradation Study on Vegetables Simultaneously

A multi-residue method for determination of pesticide residues in vegetables, using ethyl acetate extraction and determination by means of GC–MSD, is presented. The method includes as many as 27 pesticides such as organophosphorous, organohalogen, organonitrogen and pyrethroids pesticides, which are in common use or forbidden on vegetables in China. After extraction with ethyl acetate, the extract is concentrated and evaporated to dryness and redissolved in ethyl acetate before injection on GC–MSD. The recoveries were obtained in the range 70–100% with 5 exceptions in lettuce and 7 exceptions in cucumber, relative standard deviations between 1.92% and25.39% by means of standard addition to the vegetables blank extracts. The degradation of some pesticides in the 27 was studied by the method developed, the mixture of the pesticides commercial formulations was sparged on the vegetables, then the residues of samples obtained in different time were determined by the developed method. The determination indicated that (all pesticides were used as the instruction): 1.a pesticide, used on different plants, the quantity of the pesticide on the part for people’s dietary differs greatly; 2. some pesticides, degradating slowly and with a large dose, are inappropriate used on vegetables which remain on cropland for a short time. This research does not develop models for pesticides degradation, but provides some data on the safe intervals of the pesticides and a potential method for the study of multi-class pesticides safe intervals on a plant simultaneously.

Determination of Pesticide Residues in Lettuce by Gas Chromatography with Electron-Capture Detection

A sensitive, rapid, and simple multiresidue method for the simultaneous determination of 19 pesticides in different varieties of lettuce (Lactuca sativum) was developed. Lettuce samples were extracted by homogenization with acetone and partitioned into ethyl acetate-cyclohexane. Subsequent sample cleanup was not needed. Final determination was made by capillary gas chromatography (GC) with electron-capture detection (ECD). Confirmation analysis of pesticides was performed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recovery by the GC-ECD method obtained for these compounds varied from 66.4 to 119.2% with relative standard deviations < 7.7%. The GC-ECD method has good linearity, and the detection limit for the pesticides studied varied from 0.1 to 3.8 microg/kg. The proposed method was used to determine pesticide levels in different types of lettuce grown in soils from experimental fields.

Simplified multiresidue method for determination of pesticide residues in lettuce by gas chromatography with nitrogen-phosphorus detection.

A rapid and simple method has been developed for simultaneous determination of different classes of pesticide in different varieties of lettuce (Lactuca sativum). Lettuce samples were extracted by homogenization with acetone and partitioned into ethyl acetate-cyclohexane. Subsequent sample clean-up was not needed. Pesticide residues were determined by capillary gas chromatography with nitrogen-phosphorus detection (NPD). Confirmatory analysis of the pesticides was performed by capillary gas chromatography coupled with mass spectrometry in selected-ion-monitoring (SIM) mode. Recovery at two levels of fortification (ca. 0.05 and 0.20 mg kg(-1)) ranged from 63.9 to 118.6%, and relative standard deviations were below 9.5%. The proposed method was used to determine pesticide levels in different types of lettuce grown in soil from experimental fields.

Multi-residue screening of pesticides in vegetables, fruits and baby food by stir bar sorptive extraction–thermal desorption–capillary gas chromatography–mass spectrometry

The performance of stir bar sorptive extraction (SBSE) for the enrichment of pesticides from vegetables, fruits and baby food samples is discussed. After extraction with methanol, an aliquot is diluted with water and SBSE is performed for 60 min. By applying a new thermal desorption unit (TDU), fully automated and unattended desorption of 98 stir bars is feasible, making SBSE very cost-effective. The presence of pesticide residues is elucidated with the retention time locked gas chromatography–mass spectroscopy method (RTL-capillary GC–MS). With SBSE–RTL-capillary GC–MS operated in the scan mode, more than 300 pesticides can be monitored in vegetables, fruits and baby food. The multi-residue method (MRM) described provides detectabilities from the mg/kg (ppm) to the sub-μg/kg (ppb) level, thereby complying with the maximum residue levels (MRLs) set by regulatory organizations for pesticides in different matrices. Several examples, i.e. pesticide residues in lettuce, pears, grapes and baby food, illustrate the potential of SBSE–RTL-capillary GC–MS.

Analysis of pesticide residues in lettuce by large volume-difficult matrix introduction-gas chromatography-time of flight-mass spectrometry (LV-DMI-GC-TOF-MS).

A multi-residue method is described that eliminates the need for a clean-up step and thus allows the rapid determination of pesticides in crude extracts of lettuce. Samples were extracted with a mixture of ethyl acetate, Na2SO4 and NaHCO3 and the crude extracts analysed directly using large volume-difficult matrix introduction (LV-DMI) in combination with gas chromatography-time of flight-mass spectrometry (GC-TOF-MS). The LV-DMI procedure described was evaluated for the analysis of dimethoate, pyrimethanil, chlorothalonil, vinclozolin, furalaxyl and oxadixyl. Satisfactory response was obtained at the lowest calibrated level (LCL) of 0.0025 microg ml(-1), with good linearity over the range 0.0025-0.5 microg ml(-1) (0.005-1.0 mg kg(-1) equivalent). Average recoveries between 73 and 118% were obtained at the 0.01-0.5 mg kg(-1) levels with RSD values < or = 13%.

상추의 생산단계별 Chlorpyrifos 및 Procymidone의 잔류허용기준 설정

상추의 생산단계에서의 잔류허용기준 설정과 최종 소비단계에서의 안전성 평가자료로 활용하기 위하여 지금까지 상추수확물에서의 잔류수준과 검출빈도가 높은 것으로 알려진 살충제 chlorpyrifos 및 살균제 procymidone의 포장상태에서의 생물학적 반감기, 보관상태에 따른 잔류량 변화 그리고 세척형태에 따른 제거율을 조사하였다. 시설재배포장에서 상추중두 약제의 살포농도별 생물학적 반감기를 측정한 결과 기준량 살포의 경우 chlorpyrifos 1.2일 및 procymidone 1.3일 배량살포의 경우에는 chlorpyrifos 1.5일 및 procymidone 2.6일로 나타났다. 유통과정중에서 일어날 수 있는 두 가지 농약의 잔류량 변화를 알아보기 위해서 실온(20<TEX>$^{\circ}C$</TEX>) 및 냉장(4<TEX>$^{\circ}C$</TEX>) 상태로 보관하면서 두 약제의 잔류량 변화를 조사한 결과 반감기는 실온저장시 chlorpyrifos 3.8일, procymidone 20.9일이었고, 냉장저장시에는 chlorpyrifos 12.4일 procymidone 20.9일로 나타나 두 약제 모두 실온저장보다 냉장저장시 잔류량의 감소가 훨씬 느린 것으로 나타났다. 세척방법에 의한 잔류농약의 감소량을 조사한 결과 세제 사용시의 평균 제거율은 chlorpyrifos 48.3%, procymidone 52.6%로 나타났고, 물 사용 시에는 chlorpyrifos 31.3%, procymidone 38.1%로 나타났다. Two pesticides commonly used for lettuce cultivation including chlorpyrifos and procymidone were subjected to a field residue trial to ensure safety of terminal residues in the harvest. After pesticides were applied at standard and double rates in a foliar spray, leaf persistence of their residues was investigated far 10 days prior to harvest. Even though far exceeded the tolerances, initial leaf residues were rapidly dissipated with time and remained only 0.4<TEX>$\sim$</TEX>7.2% of the residues in the harvest. As well fitted by the first-order kinetics, biological half-lives of the pesticide residues in lettuce leaves ranged 1.2<TEX>$\sim$</TEX>2.6 days. Slow dissipation of the residues in the harvest was observed during storage at room temperature and 4<TEX>$^{\circ}C$</TEX> for 7 days. Portions of dislodgeable residues which resided in detergent washings decreased as time elapsed. Patterns in dissipation and distribution of dislodgeable residues were not largely affected by the application rate of pesticides. It is concluded that timing of pesticide application, that is, pre-harvest interval would be the first factor to determine the terminal residue level in edible portions of lettuce.