The Assessment of Organophosphate Pesticide Exposure among School Children in Four Regions of Thailand: Analysis of Dialkyl Phosphate Metabolites in Students' Urine and Organophosphate Pesticide Residues in Vegetables for School Lunch

Environmental pesticide exposure and its association with hematological parameters and inflammation indices among school-aged children in Mexico

Few studies have investigated the association between pesticide exposure and immune-inflammatory indices in children. We conducted a cross-sectional study of 369 school-aged children from three Mexican communities with varying levels of agricultural production. Blood samples were collected to calculate immune-inflammatory indices, and pooled hand-washing samples from 30 randomly selected children per community were analyzed for pesticide metabolites. Urinary dialkylphosphates (DAP) were determined in pooled samples per community. Multivariable logistic regression models assessed associations between pesticide exposure and immune-inflammatory indices (>median vs. Collapse

Key Words

• Children
• DAP
• Inflammation indices
• Pesticide

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MESH Headings

• Humans
• Mexico/epidemiology
• Male
• Child
• Female
• Environmental Exposure/adverse effects
• Cross-Sectional Studies
• Pesticides/urine
• Pesticides/adverse effects
• Pesticides/toxicity
• Inflammation/blood
• Inflammation/chemically induced
• Inflammation/epidemiology
• Biomarkers/blood
• Biomarkers/urine
• Environmental Monitoring
• Environmental Pollutants/urine
• Pesticide Residues
• Adolescent

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Affiliation(s)

Miguel Alfonso Ruiz-Arias Programa de Maestría y Doctorado en Ciencias Biológico Agropecuarias, Área de Ciencias Ambientales, Universidad Autónoma de Nayarit, Nayarit, Mexico; Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico
Yael Yvette Bernal-Hernández Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico
Irma Martha Medina-Díaz Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico
Ana M Mora Center for Environmental Research and Community Health (CERCH), School of Public Health, University of California, Berkeley, CA 94720, United States
José Francisco Herrera-Moreno Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico; Secretaría de Ciencia, Humanidades, Tecnología e Innovación (SECIHTI), Padrón de Investigadoras e Investigadores por México, Mexico
Briscia Socorro Barrón-Vivanco Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico
Cyndia Azucena González-Arias Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico
Francisco Alberto Verdín-Betancourt Unidad Especializada de Ciencias Ambientales. CENITT, Av. Emilio M. González S/N. Ciudad del Conocimiento, Tepic, Nayarit, Mexico
José Antonio Aguilar-Bañuelos Programa de Maestría y Doctorado en Ciencias Biológico Agropecuarias, Área de Ciencias Ambientales, Universidad Autónoma de Nayarit, Nayarit, Mexico; Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico
Juan Manuel Agraz-Cibrián Unidad Académica de Ciencias Químico Biológicas y Farmacéuticas, Universidad Autónoma de Nayarit, Tepic 63000, Mexico
José Francisco Zambrano-Zaragoza Unidad Académica de Ciencias Químico Biológicas y Farmacéuticas, Universidad Autónoma de Nayarit, Tepic 63000, Mexico
Pedro de Jesús Bastidas-Bastidas Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (Residuos de Plaguicidas), Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Unidad Culiacán, Carretera a Eldorado Km. 5.5, Mexico
Aurora Elizabeth Rojas-García Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado. Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. Col. Centro, C.P, Tepic, Nayarit 63000, Mexico.

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Portable Thiocholine-Based Sensor for Monitoring Blood Cholinesterase Activity and Detecting Organophosphate and Carbamate Pesticides Using Personal Glucose Meters

The widespread use of organophosphate and carbamate pesticides in agriculture poses significant health risks due to their cholinesterase (ChE) inhibitory effects. However, existing detection methods are often expensive and require specialized facilities, limiting their accessibility. This study developed a cost-effective, portable, and sensitive sensor using personal glucose meter (PGM) technology to detect ChE activity in human blood and pesticide residues in vegetables. A thiocholine-based assay was designed to measure ChE activity via PGM, enabling the assessment of enzyme inhibition caused by pesticide exposure. The optimized PGM-based sensor achieved limits of detection (LODs) of 0.138 ppm for mevinphos and 0.113 ppm for carbofuran in standard solutions, with strong correlations (R > 0.99) between standard and fortified samples, indicating high sensitivity and accuracy. The method demonstrated reliable detection of ChE inhibition at pesticide concentrations as low as 0.05 ppm. The developed sensor offers a portable and efficient tool for point-of-care diagnostics, environmental monitoring, and food safety applications. This approach enhances public health protection by enabling accessible pesticide detection. Future work will focus on expanding detection capabilities, improving specificity and stability, and conducting clinical validation for broader applications.

Neurobehavioral Performance in Preschool Children Exposed Postnatally to Organophosphates in Agricultural Regions, Northern Thailand

Evidence of the effects of postnatal exposure to organophosphates (OPs) on children's neurodevelopment remains limited but crucial. This cross-sectional study evaluated exposure to OPs and neurobehavioral performance in 172 preschool children. Urinary dialkyl phosphate (DAP) metabolites, biomarkers for exposure to OPs, were measured. The neurobehavioral assessments included motor skills, memory, and cognitive function, measured using the Purdue pegboard test, digit span test, object memory test, and visual-motor integration. Multiple linear regression models were employed to explore the associations between urinary DAP metabolite levels and neurobehavioral performance, adjusting for potential confounders. Findings revealed that children of farming parents had higher urinary levels of dimethylphosphate (DMP) (Beta = 0.730, 95% CI = 0.138, 1.322, p value = 0.016) and diethylphosphate (DEP) (Beta = 0.668, 95% CI = 0.044, 1.291, p value = 0.036). Additionally, high fruit consumption correlated with increased urinary DEP levels (Beta = 0.398, 95% CI = 0.063, 0.733, p value = 0.020). Critically, elevated urinary DEP was associated with poorer fine motor coordination, affecting performance in the Purdue pegboard test for the dominant hand (Beta = -0.428, 95% CI = -0.661, -0.194, p value < 0.001), the preferred hand (Beta = -0.376, 95% CI = -0.603, -0.149, p value = 0.001), and both hands (Beta = -0.524, 95% CI = -0.773, -0.276, p value < 0.001). These findings highlight the role of parental occupation and diet in children's OP exposure and suggest that OP exposure negatively impacts fine motor coordination. Targeted interventions, such as promoting organic diets, enhancing workplace safety, and ongoing biomonitoring, are vital to reduce neurodevelopmental risks for vulnerable populations.

Organophosphate insecticide exposure and respiratory symptoms among school children in Northern Thailand: Interaction by biomass burning, dampness and season

The aim was to study associations between dialkylphosphates (DAPs), organophosphate (OP) metabolites in urine, biomarkers of OP insecticide exposure, and respiratory symptoms among children in upper northern Thailand. We recruited junior high school children in randomly selected schools in four cities (N = 337), with repeated data collection in wet and dry seasons. Urine was collected and analyzed for six OP metabolites, with creatinine adjustment. Total DAP was expressed as sum of DAPs. Data on respiratory symptoms was collected by a standardized questionnaire. Associations were analyzed by multiple logistic regression. Totally 11.3 % lived in farm families. Total DAPs concentration was higher in dry season (p = 0.002) but did not differ between farm and non-farm children. Total DAPs in wet season was associated with current wheeze (p = 0.019), current asthma attacks (p = 0.012) and attacks of breathlessness in last 12 months (p = 0.021). Total DAPs in dry season was associated with current wheeze (p = 0.042), and associations between DAPs and respiratory symptoms were stronger for dimethylphosphate metabolites (DMPs) than for diethylphosphate metabolites (DEPs). DMPs are produced by certain OP pesticides. Biomass burning inside or outside the home, and dampness or mold at home, enhanced the association between total DAPs and attacks of breathlessness. In conclusion, OP pesticide exposure, measured as urinary DAPs, was higher in dry season and similar in farm and non-farm children. OPs exposure, especially to DMP related pesticides, can increase asthmatic symptoms, especially in wet season. Combined exposure to OP and smoke from biomass burning, or dampness and mold, can further increase the prevalence of attacks of breathlessness. There is a need to reduce OP insecticide and biomass smoke exposure among Thai children. Since different pesticides can be used in different seasons, studies on respiratory health effects of OPs pesticide exposure should be done in different seasons.

A Comprehensive Review on Pesticide Residues in Human Urine

Numerous studies worldwide have evaluated pesticide residues detected in urine. This review serves as a contribution to this field by presenting an overview of scientific research studies published from 2001 to 2023, including details of study characteristics and research scope. Encompassing 72 papers, the review further delves into addressing key challenges in study design and method used such as sampling and analytical approaches, results adjustments, risk assessment, estimations, and results evaluation. The review explores urinary concentrations and detection frequency of metabolites of organophosphates and pyrethroids, as well as herbicides such as 2,4-D and glyphosate and their metabolites, across various studies. The association of the results with demographic and lifestyle variables were explored. While farmers generally have higher pesticide exposure, adopting organic farming practices can reduce the levels of pesticides detected in their urine. Residence close to agricultural areas has shown high exposure in some cases. Dietary exposure is especially high among people adopting a conventionally grown plant-rich dietary pattern. A higher detection level and frequency of detection are generally found in females and children compared to males. The implications of transitioning to organic and sustainable plant-rich diets for reducing pesticide exposure and potential health benefits for both adults and children require further investigation.

Advancing micro-electrometric techniques for the detection of organophosphate and carbamate residues using cricket cholinesterase

The widespread use of organophosphate (OP) and carbamate (CM) pesticides requires efficient and cost-effective detection methods. This study introduces a micro-electrometric method using cricket cholinesterase (ChE) to detect OP and CM residues, providing a rapid and economical alternative to conventional chromatographic techniques. The parameters of the method, including the substrate concentration, incubation temperature, and incubation time, were optimized. By leveraging the sensitivity of cricket ChE to OP and CM inhibition, this approach translates enzyme inhibition into an electrical signal to quantify pesticide levels, achieving an impressive limit of detection (LOD) from 0.036 to 0.086 parts per million (ppm). This method demonstrated reproducibility and stability, making it suitable for field applications and on-site testing across various environmental matrices. This research represents a significant advancement in pesticide residue analysis with potential applications in the development of portable biosensor devices for real-time environmental monitoring and public health protection.

Pesticides impacts on human health and the environment with their mechanisms of action and possible countermeasures

Pesticides are chemical constituents used to prevent or control pests, including insects, rodents, fungi, weeds, and other unwanted organisms. Despite their advantages in crop production and disease management, the use of pesticides poses significant hazards to the environment and public health. Pesticide elements have now perpetually entered our atmosphere and subsequently contaminated water, food, and soil, leading to health threats ranging from acute to chronic toxicities. Pesticides can cause acute toxicity if a high dose is inhaled, ingested, or comes into contact with the skin or eyes, while prolonged or recurrent exposure to pesticides leads to chronic toxicity. Pesticides produce different types of toxicity, for instance, neurotoxicity, mutagenicity, carcinogenicity, teratogenicity, and endocrine disruption. The toxicity of a pesticide formulation may depend on the specific active ingredient and the presence of synergistic or inert compounds that can enhance or modify its toxicity. Safety concerns are the need of the hour to control contemporary pesticide-induced health hazards. The effectiveness and implementation of the current legislature in providing ample protection for human health and the environment are key concerns. This review explored a comprehensive summary of pesticides regarding their updated impacts on human health and advanced safety concerns with legislation. Implementing regulations, proper training, and education can help mitigate the negative impacts of pesticide use and promote safer and more sustainable agricultural practices.

Integrated transcriptomic and metabolomic analyses reveal the toxic effects of dimethoate on green vegetable soya bean seedlings

The insecticide dimethoate, an organophosphate, has been used on crops, soybeans, fruits, and vegetables since the 1960s and is considered one of the most widely used pesticides. However, the understanding of the molecular mechanisms of dimethoate in crops, especially crop seedlings, is still limited. The green vegetable soya bean (Glycine max merr) is usually used as a vegetable-like fruit of soybean in many Asian countries. This study aimed to analyze the effect of dimethoate on the growth of green vegetable soya bean seedlings at the metabolic and transcriptional levels. An integrated analysis of the transcriptome and metabolome was performed to determine the responses of green vegetable soya bean seedlings to different concentrations (D1 for low dose, D2 for high dose and C for control) of dimethoate. In omics analyses, 4156 differentially expressed genes (DEGs) and 1935 differentially abundant metabolites (DAMs) were identified in the D1/C comparison, and 11,162 DEGs and 819 DAMs were identified in D2/C. Correlation analyses revealed dimethoate affected the metabolic pathways of green vegetable soya beans such as the biosynthesis of secondary metabolites and microbial metabolism in diverse environmental pathways, demonstrating that even small doses of dimethoate can affect green vegetable soya bean seedlings in a short period of time. Our study further enriches our understanding of the molecular mechanisms by which green vegetable soya beans are treated with dimethoate and provides a deeper understanding of the effects of dimethoate on crops.

Methylated dialkylphosphate metabolites of the organophosphate pesticide malathion modify actin cytoskeleton arrangement and cell migration via activation of Rho GTPases Rac1 and Cdc42

The non-cholinergic molecular targets of organophosphate (OP) compounds have recently been investigated to explain their role in the generation of non-neurological diseases, such as immunotoxicity and cancer. Here, we evaluated the effects of malathion and its dialkylphosphate (DAP) metabolites on the cytoskeleton components and organization of RAW264.7 murine macrophages as non-cholinergic targets of OP and DAPs toxicity. All OP compounds affected actin and tubulin polymerization. Malathion, dimethyldithiophosphate (DMDTP) dimethylthiophosphate (DMTP), and dimethylphosphate (DMP) induced elongated morphologies and the formation of pseudopods rich in microtubule structures, and increased filopodia formation and general actin disorganization in RAW264.7 cells and slightly reduced stress fibers in the human fibroblasts GM03440, without significantly disrupting the tubulin or vimentin cytoskeleton. Exposure to DMTP and DMP increased cell migration in the wound healing assay but did not affect phagocytosis, indicating a very specific modification in the organization of the cytoskeleton. The induction of actin cytoskeleton rearrangement and cell migration suggested the activation of cytoskeletal regulators such as small GTPases. We found that DMP slightly reduced Ras homolog family member A activity but increased the activities of Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division control protein 42 (Cdc42) from 5 min to 2 h of exposure. Chemical inhibition of Rac1 with NSC23766 reduced cell polarization and treatment with DMP enhanced cell migration, but Cdc42 inhibition by ML-141 completely inhibited the effects of DMP. These results suggest that methylated OP compounds, especially DMP, can modify macrophage cytoskeleton function and configuration via activation of Cdc42, which may represent a potential non-cholinergic molecular target for OP compounds.

Methylated and ethylated dialkylphosphate metabolites of organophosphate pesticides: DNA damage in bone marrow cells of Balb/c mice

Dialkylphosphates (DAPs), metabolites of organophosphate (OP) pesticides, are widely distributed in the environment and are often used as biomarkers of OP exposure. Recent reports indicate that DAPs may be genotoxic, both in vitro and in vivo. We have examined the genotoxicity of the methylated DAPs dimethyldithiophosphate (DMDTP) and dimethylphosphate (DMTP) and the ethylated DAPs diethyldithiophosphate (DEDTP) and diethylphosphate (DETP), in comparison with their parental compounds, malathion and terbufos, respectively, in bone marrow polychromatic erythrocytes (PCE) of male and female Balb/c mice. We also compared DNA damage (comet assay) induced by DMDTP and dimethyl phosphate (DMP) in human cell lines. Both DMDTP and DMP caused DNA damage in peripheral blood mononuclear cells, HeLa cells, and the hepatic cell lines HepG2 and WRL-68. In the in vivo micronucleus assay, methylated and ethylated DAPs increased micronucleated PCE cells in both male and female mice. Female mice were more susceptible to DNA damage. In comparison to their parental compounds, methylated DAPs, particularly DMTP, were more genotoxic than malathion; DEDTP, DETP, and terbufos were similar in potency. These results suggest that DAPs may contribute to DNA damage associated with OP pesticide exposure.