Determination of 17 organophosphate pesticide residues in mango by modified QuEChERS extraction method using GC-NPD/GC-MS and hazard index estimation in Lucknow, India

Residue behaviour and health risk assessment of chlorpyrifos and mancozeb in apple fruits and soil

Mancozeb residue estimation was done using second derivative ultraviolet spectroscopy by Shimadzu ultraviolet-visible spectrophotometer, and chlorpyrifos was estimated by QuEChERS technique using GC-FPD. The persistence for chlorpyrifos was carried out at two locations, and for mancozeb, persistence studies were carried out at four locations. Initial deposits of mancozeb on apple fruits ranged from 1.33 to 1.63 mg/kg at the recommended dose and from 2.55 to 3.26 mg/kg at double the recommended dose at all four locations. Chlorpyrifos residues in apple fruits had an initial deposit of 0.94-0.99 mg/kg at recommended dose and 1.75-1.92 mg/kg at double the recommended dose. Mancozeb residues in apple fruit were below the detection limit (BDL) after 20 days at recommended dose and after 25 days at double the recommended dose at two locations, while mancozeb residue at the other two locations and the residues of chlorpyrifos at all locations reached BDL after 15 and 20 days at recommended and double the recommended doses, respectively. Half-life of mancozeb varied from 3.07 to 4.02 days at recommended dose and from 3.30 to 4.32 days at double the recommended dose, whereas chlorpyrifos residues dissipated to half their initial concentration on 2.33-2.35 days at recommended dose and 2.89-2.90 days at double the recommended dose. The soil samples showed no presence of residues of chlorpyrifos and mancozeb at harvest. The risk assessment revealed that hazard quotient for the intake of mancozeb was in the range of 0.06-0.13% and 0.20-0.44% for rural and urban population, while for the intake of chlorpyrifos, hazard quotient was in the range of 0.10-0.12% for rural population and 0.33-0.38% for urban population, and theoretical maximum dietary intake (9.67 × 10-5 mg/person and 3.18 × 10-4 mg/person for rural population and urban population in case of mancozeb and 3.22 × 10-5 mg/person and 1.06 × 10-4 mg/person for rural population and urban population in case of chlorpyrifos) was also found to be less than maximum permissible intake (1.38 mg/kg for mancozeb and 0.60 mg/kg for chlorpyrifos). The results of risk assessment thereby indicated that apple consumption does not pose a risk to human health.

Current-use pesticide exposure pathways in Czech adults and children from the CELSPAC-SPECIMEn cohort

INTRODUCTION

In this study, we aimed to characterise exposure to pyrethroids, organophosphates, and tebuconazole through multiple pathways in 110 parent-child pairs participating in the CELSPAC-SPECIMEn study.

METHODS

First, we estimated the daily intake (EDI) of pesticides based on measured urinary metabolites. Second, we compared EDI with estimated pesticide intake from food. We used multiple linear regression to identify the main predictors of urinary pesticide concentrations. We also assessed the relationship between urinary pesticide concentrations and organic and non-organic food consumption while controlling for a range of factors. Finally, we employed a model to estimate inhalation and dermal exposure due to spray drift and volatilization after assuming pesticide application in crop fields.

RESULTS

EDI was often higher in children in comparison to adults, especially in the winter season. A comparison of food intake estimates and EDI suggested diet as a critical pathway of tebuconazole exposure, less so in the case of organophosphates. Regression models showed that consumption per g of peaches/apricots was associated with an increase of 0.37% CI [0.23% to 0.51%] in urinary tebuconazole metabolite concentrations. Consumption of white bread was associated with an increase of 0.21% CI [0.08% to 0.35%], and consumption of organic strawberries was inversely associated (-61.52% CI [-79.34% to -28.32%]), with urinary pyrethroid metabolite concentrations. Inhalation and dermal exposure seemed to represent a relatively small contribution to pesticide exposure as compared to dietary intake.

CONCLUSION

In our study population, findings indicate diet plays a significant role in exposure to the analysed pesticides. We found an influence of potential exposure due to spray drift and volatilization among the subpopulation residing near presumably sprayed crop fields to be minimal in comparison. However, the lack of data indicating actual spraying occurred during the critical 24-hour period prior to urine sample collection could be a significant contributing factor.

Green Spectrophotometric Determination of Organophosphate in Selected Fruits and Vegetables

A simple, sensitive, precise, and environmentally safe spectrophotometry method was developed and validated for the determination of organophosphate in various fruits and vegetables using a UV-Visible spectrophotometer using a magnesia mixture. The volume of reagent used for analysis and the stability of the color complex were also optimized. The drug showed a stable white color complex at 420 nm. The greenness of the methods was estimated using an ecoscale (84), the Green Analytical Procedure Index, and AGREE (0.89), which were found to be excellent green method based on spectrophotometric determination. The method was validated using ICH guidelines and has acceptable values for linearity (0.5-2.5 mg/ml), accuracy (98.5-102.5%), precision, robustness, limit of detection (0.16 mg), and limit of quantification (0.486 mg). The concentration of the organophosphate in the analyzed sample was in the range of 0.003 to 2.45 mg. Altogether, the proposed green analytical method was found to be a simple, selective, sensitive, accurate, and ecofriendly method for the analysis of organophosphate in various fruits and vegetables.

Determination of multi-class pesticide residues in food commodities from Gujarat, India and evaluation of acute and chronic health risk

An increasing concern for food safety has drawn attention to the overuse of pesticides, which pose a risk to public health. The present study determined 61 pesticide residues in 120 samples of cauliflower, green chili, cucumber, grapes, bananas and mangoes samples, and these were collected from markets in Ahmedabad, Gandhinagar, Surendranagar, Anand and Sabarkantha districts of Gujarat state, India. The samples were extracted and analyzed using ultra-high performance liquid chromatography-time of flight mass spectrometry (UHPLC-q-TOF-MS) and Gas chromatography-tandem mass spectrometry (GC-MS/MS). In addition, the health risk assessment associated with pesticide residues were evaluated by calculating the Hazard Quotient (HQ) and Hazard Index (HI), which indicate a value of less than 1 is safe for consumption. Out of 61 pesticide residues, 29 residues were detected in 107 samples; 68 samples showed multiple residues, and 39 samples found a single residue. Pesticides such as dimethoate, λ-cyhalothrin, fenvalerate, bifenthrin, and cyfluthrin were frequently detected in samples. HI in adults and adolescents confirmed a value less than 1 in cauliflower, cucumber, grapes and mango samples and greater than 1 in green chili and banana samples, respectively. The overall results depicted that, no considerable risk was observed in the selected food commodities. However, green chili and banana samples were found to exhibit marginal risk to human health. As a result, proper application, implementation of control plans, and continuous monitoring are required to prevent the risk and safeguard human health.

Multi-residue Analysis, Probabilistic Dietary Risk Assessment of 241 Pesticides in Wheatgrass (Triticum sp.) using LC-MS/MS in Combination with QuEChERS Extraction

Wheatgrass is consumed as an important nutritious herbal food supplement across the globe; however, limited studies have been reported on analysis of multi-class pesticides in this complex nutrient rich natural product. An analytical method was developed for the estimation of 241 pesticides in random Wheatgrass samples collected from Delhi-Northern Capital Region (Delhi-NCR). Extraction was performed by QuEChERS, cleaning was performed by dispersive solid phase and the extracts were analyzed using Triple Quadrupole Liquid Chromatography Mass Spectrometry. The limit of quantification was 0.5 μg /kg, which is well below European Union-Maximum Residue Level. The coefficient of determination was >0.991 across calibration range of 0.5-100 μg /kg. The Relative Standard Deviation values for 231 pesticides based on 10 replicates of samples spiked at 10 μg /kg were <5%. Among random samples, 54% confirmed the presence of at least one pesticide. Results indicated the presence of 8 different pesticides among 38% of total population with Metribuzin at 299.7 μg /kg and Carfentrazone-ethyl at 19.47 μg/kg exceeding the permissible limits among 6% of total estimated population. The chronic and acute risk quotients as calculated were less than 1, indicating non-significant dietary risk to consumers. However, the presence of pesticides above permissible limit is likely to result in adverse health effects to the consumers of herbal supplements from urban population and incorporating measures would be useful to ensure the quality and safety of wheatgrass consumption.

MPH-GST sensing microplate for easy detection of organophosphate insecticides

OBJECTIVE

To develop a convenient and efficient means for organophosphate (OP) insecticide detection, a simple, cost-effective, and easy-to-use absorbance-based sensing device was generated using methyl parathion hydrolase fused with glutathione-S-transferase (MPH-GST) covalently immobilized onto a chitosan film-coated microplate.

RESULTS

With methyl parathion (MP) as a representative substrate, this MPH-GST sensing microplate had the detection limit of 0.1 µM and the linear range of 0.1-50 µM. Despite its highest stability at 4 °C, it was considerably stable at 25 °C with high activity for 30 days. It was also most stable at pH 8.0 and could be efficiently reused up to 100 rounds. The device revealed a high percentage of recovery for tap water spiked with a known concentration of MP, which was also comparable to the result obtained from gas chromatography-mass spectrometry. It also showed a high recovery of 82-100% with MP spiked agricultural products and satisfactory results with non-spiked samples. This immobilized enzyme sensing system was more sensitive and efficient than the whole cell system from our previous work.

CONCLUSIONS

All of the advantages of the MPH-GST sensing microplate developed have rendered it suitable for rapid and convenient OP screening, and for being a bio-element for fabricating a potential optical biosensor in the future.

Co-exposure risks of pesticides residues and bacterial contamination in fresh fruits and vegetables under smallholder horticultural production systems in Tanzania

This study was carried out to investigate the risks of simultaneous exposure to pesticide residues and bacteria contaminants in locally produced fresh vegetables and vegetables in Tanzania. A total of 613 samples were analyzed for pesticide residues, out of which 250 were also analyzed for bacterial contamination. Overall, 47.5% had pesticide residues, 74.2% exceeded Maximum Residue Levels (MRLs). Organophosphorus (95.2%), organochlorines (24.0%), pyrethroids (17.3%), and carbamates (9.2%) residues dominated. MRL values were mostly exceeded in tomatoes, onions, watermelons, cucumbers, Chinese cabbage, and sweet paper. Tetramethrin (0.0329-1.3733 mg/kg), pirimiphos-methyl (0.0003-1.4093 mg/kg), permethrin (0.0009-2.4537 mg/kg), endosulfan (beta) (0.0008-2.3416 mg/kg), carbaryl (0.0215-1.5068 mg/kg), profenofos (0.0176-2.1377 mg/kg), chlorpyrifos (0.0004-1.2549 mg/kg) and dieldrin (0.0011-0.5271 mg/kg) exceeded MRLs. The prevalence of bacteria contamination was high (63.2%). Enterobacter (55.6%) Pseudomonas aeruginosa (32.4%), E. coli (28.2%), Citrobacter (26.8%), Klebsiella oxytoca (14.8%), and Salmonella (7.7%) were isolated. Furthermore, 46.4% tested positive for both pesticide residues and bacterial contaminants. Vegetables from farms (60.7%) contained more dual contaminants than market-based vegetables (41.8%). This may have resulted from excessive pesticide use and unhygienic handling of fresh fruits and vegetables at production level. Binary logistic regression showed that fresh fruits and vegetables with pesticide residues were 2.231 times more likely to have bacteria contaminants (OR: 2.231; 95% CI: 0.501, 8.802). The contamination levels of pesticide residues and bacterial contaminants could be perceived as a serious problem as most fresh fruits and vegetables recorded values of pesticide residues far above the MRLs with pathogenic bacteria isolated in higher proportions. MRLs was higher in most vegetables consumed raw or semi-cooked such as watermelons, carrots, cucumber, tomatoes, onion and sweet paper. There is an urgent need to develop pesticide monitoring and surveillance systems at farmer level, educating farmers and promoting the use of greener pesticides to mitigate the health effects of pesticides and bacterial contaminants.

Proposing new approaches for the risk characterisation of single chemicals and chemical mixtures: The source related Hazard Quotient (HQS) and Hazard Index (HIS) and the adversity specific Hazard Index (HIA)

A hazard quotient (HQ) for a single chemical and the hazard index (HI) for a mixture of chemicals were first described as approaches for risk characterisation by the EPA. HQ is defined as the ratio of exposure to an appropriate reference dose such as the ADI. HI is the sum of the HQs of the chemicals in a mixture. HQ and HI have been used to characterise risk after various exposure scenarios. However, both approaches have a significant limitation in the way they are used. The accurate use of HQ or HI requires estimation of aggregate exposure, that is, exposure to a given chemical(s) from all possible relevant sources. In many studies, risk is assessed assuming exposure from a specific source such as, consumption of water or a specific food item, in which chemical(s) concentration(s) have been measured. In this case the classic HQ/HI approach can result in significant underestimation of risk. For this purpose, we developed an alternative approach, named as Source Related HQ (HQs) where HQS is the ratio of the exposure from the specific source of interest to the respected reference values. According to our approach the HQS, before being compared to the reference dose, should be adjusted by a correction factor, in order to simulate aggregated exposure. A correction factor can be calculated based on the permitted exposure contribution from the specific source to the permitted aggregated exposure. Another important limitation specific to the HI approach is the use of chemical specific ADIs that do not correspond to the same critical effect. In this study, we present an analysis based on the individual critical effects, in order to derive the critical effect and an adversity specific Hazard Index (HIA) and risk characterisation for the whole mixture.

Determination of pesticide and phthalate residues in tea by QuEChERS method and their fate in processing

In this study, the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied for the analysis of the multiclass pesticide residues of 12 organochlorines (OCs), 9 organophosphates (OPs), 11 synthetic pyrethroids (SPs), 4 herbicides, 6 phthalates in raw tea (loose tea, branded tea and herbal tea), and tea infusion in 4 different containers (glass cup, earthen cup, plastic bag and disposal cup). In loose tea and branded tea residues, malathion (0.257 and 0.118 mg kg^-1), cypermethrin (0.065 and 0.030 mg kg^-1), and fenvalerate (0.032 and 0.030 mg kg^-1) were detected, respectively. In herbal tea, residues of only cypermethrin (0.053 mg kg^-1) and fenvalerate (0.045 mg kg^-1) were detected. Tea infusion samples contained in a plastic bag were found to be contaminated with only dibutyl phthalate (DBP) (0.038 mg kg^-1). Disposable cup was found to be contaminated with DBP (0.026 mg kg^-1) and diethyl phthalate (DEP) (0.004 mg kg^-1). Further, to know the processing behavior of pesticides, the spiked raw tea was subjected to tea infusion at different brewing times (2, 5, 10 min). The analysis demonstrated that dimethoate, dichlorvos, and malathion had shown more than 10 % of translocation at 5 min of brewing time. Further brewing for 10 min revealed the reduction in concentration of pesticides. Leaching of phthalate residues from different plastic containers was also studied at 10, 30, and 60 min. DBP, benzyl butyl phthalate (BzBP), and di-2-(ethylhexyl) phthalate (DEHP) were leached in the tea infusion samples packed in plastic bags. On the other hand, in disposable cups, leaching of DBP, DEP, and dimethyl phthalate were found. The concentration of phthalate residues increased with retention time. Pesticide and phthalate contaminants were recorded at low quantities in few samples only.