Variability in urinary neonicotinoid concentrations in single-spot and first-morning void and its association with oxidative stress markers

Associations between specific volatile organic chemical exposures and cardiovascular disease risks: insights from NHANES

Introduction

An increasing body of research has demonstrated a correlation between pollutants from the environment and the development of cardiovascular diseases (CVD). However, the impact of volatile organic chemicals (VOC) on CVD remains unknown and needs further investigation.

Objectives

This study assessed whether exposure to VOC was associated with CVD in the general population.

Methods

A cross-sectional analysis was conducted utilizing data from five survey cycles (2005-2006, 2011-2012, 2013-2014, 2015-2016, and 2017-2018) of the National Health and Nutrition Examination Survey (NHANES) program. We analyzed the association between urinary VOC metabolites (VOCs) and participants by multiple logistic regression models, further Bayesian Kernel Machine Regression (BKMR) models and Weighted Quantile Sum (WQS) regression were performed for mixture exposure analysis.

Results

Total VOCs were found to be positively linked with CVD in multivariable-adjusted models (p for trend = 0.025), independent of established CVD risk variables, such as hypertension, diabetes, drinking and smoking, and total cholesterol levels. Compared with the reference quartile of total VOCs levels, the multivariable-adjusted odds ratios in increasing quartiles were 1.01 [95% confidence interval (CI): 0.78-1.31], 1.26 (95% CI: 1.05-1.21) and 1.75 (95% CI: 1.36-1.64) for total CVD. Similar positive associations were found when considering individual VOCs, including AAMA, CEMA, CYMA, 2HPMA, 3HPMA, IPM3 and MHBMA3 (acrolein, acrylamide, acrylonitrile, propylene oxide, isoprene, and 1,3-butadiene). In BKMR analysis, the overall effect of a mixture is significantly related to VOCs when all chemicals reach or exceed the 75th percentile. Moreover, in the WQS models, the most influential VOCs were found to be CEMA (40.30%), DHBMA (21.00%), and AMCC (19.70%).

Conclusion

The results of our study indicated that VOC was all found to have a significant association with CVD when comparing results from different models. These findings hold significant potential for public health implications and offer valuable insights for future research directions.

Widespread occurrence of two typical N, N'-substituted p-phenylenediamines and their quinones in humans: Association with oxidative stress and liver damage

While N, N'-substituted p-phenylenediamines (PPDs) and their quinone derivatives (PPDQs) have been widely detected in the environment, there is currently limited data on their occurrence in humans. In this study, we conducted the first serum analysis of two PPDs and PPDQs in the healthy and secondary nonalcoholic fatty liver disease (S-NAFLD) cohorts in South China. The concentrations of four oxidative stress biomarkers (OSBs), namely, 8-iso-prostaglandin F2α (8-PGF2α), 11β-prostaglandin F2α (11-PGF2α), 15(R)-prostaglandin F2α (15-PGF2α), and 8-hydroxy-2'-deoxyguanosine in serum samples were also measured. Results showed that N-(1,3-dimethybutyl)-N'-phenyl-p-phenylenediamine (6PPD) quinone was the predominant target analytes both in the healthy and S-NAFLD cohorts, with the median concentrations of 0.13 and 0.20 ng/mL, respectively. Significant (p < 0.05) and positive correlations were found between 6PPD concentration and 8-PGF2α, 11-PGF2α, and 15-PGF2α in both the healthy and S-NAFLD cohorts, indicating that 6PPD may be associated with lipid oxidative damage. In addition, concentrations of 6PPD in serum were associated significantly linked with total bilirubin (β = 0.180 μmol/L, 95%CI: 0.036-0.396) and direct bilirubin (DBIL, β = 0.321 μmol/L, 95%CI: 0.035-0.677) related to hepatotoxicity. Furthermore, 8-PGF2α, 11-PGF2α, and 15-PGF2α mediated 17.1%, 24.5%, and 16.6% of 6PPD-associated DBIL elevations, respectively. Conclusively, this study provides novel insights into human exposure to and hepatotoxicity assessment of PPDs and PPDQs.

Urinary neonicotinoid concentrations and obesity: A cross-sectional study among Chinese adolescents

Epidemiological and toxicological studies on neonicotinoids and obesity have been relevant to adults and young children, but data are limited in adolescents. This study aimed to examine the association between urinary neonicotinoid concentrations and obesity measures among Chinese adolescent. A total of 524 urine samples from 300 boys (11.3-16.1 years) and 224 girls (12.1-15.8 years) were collected to detect the concentrations of eleven neonicotinoids. Generalized linear regression, weighted quantile sum regression (WQS) and Bayesian kernel machine regression (BKMR) were used to estimate covariate-adjusted associations between detectable neonicotinoids and ten indicators of obesity. Nitenpyram concentration was associated with increased body mass index z-score (β = 0.170, 95% CI: 0.041, 0.299) and greater odds of being general obesity (OR = 2.46, 95% CI: 1.11, 5.46). N-desmethyl- acetamiprid concentration was associated with an increase in waist-to-height ratio (β = 0.102, 95% CI: 0.029, 0.176) and waist-to-hip ratio (β = 0.083, 95% CI: 0.011, 0.155). The concentrations of clothianidin (OR = 2.06, 95% CI: 1.10, 3.88) and flonicamid (OR = 2.39, 95% CI: 1.07, 5.32) were associated with greater odds of being abdominal obesity. In contrast, the concentrations of imidacloprid (OR = 0.35, 95% CI: 0.14, 0.88) and thiacloprid (OR = 0.28, 95% CI: 0.08, 0.99) were associated with lower odds of being general obesity. The estimates of general obesity and abdominal obesity increased significantly when concentrations of neonicotinoids mixture were at or above the 55th and 65th percentiles, respectively, compared to the 50th percentile concentration. Sex modified the association between nitenpyram and clothianidin and the risk of obesity with a positive association among boys, and a nonsignificant inverse association among girls. The findings suggest that these associations may be mixed and sex-specific.

Urinary biomarkers of exposure to organophosphate, pyrethroid, neonicotinoid insecticides and oxidative stress: A repeated measurement analysis among pregnant women

Exposure to insecticides may be associated with increased oxidative stress (OS), but few studies have assessed the associations of OS biomarkers (OSBs) with exposure to multiple insecticides and their mixture, especially in pregnant women who are a vulnerable population. In the present study, 1,094 Chinese pregnant women were recruited and a total of 3,282 urine samples were collected at their three trimesters to measure eight metabolites of organophosphates, three metabolites of pyrethroids, nine typical neonicotinoids/their metabolites, and three OSBs of DNA damage (8-OHdG), RNA damage (8-OHG), and lipid peroxidation (HNE-MA). Among the twenty target insecticide metabolites, sixteen of them were frequently detected; thirteen of them were detected in over 86% of all the urine samples except for imidacloprid (IMI, detection frequency: 72.9%), desnitro-imidacloprid (DN-IMI, 70.0%), and clothianidin (CLO, 79.6%). The reproducibility of their concentrations across the three trimesters was poor to fair (intraclass correlation coefficients <0.50). Multiparity and warm season were related to higher urinary levels of some insecticide metabolites, while higher education level and inadequate weight gain during pregnancy were significantly associated with lower concentrations of certain insecticide metabolites. Linear mixed model analyses suggested that almost all the frequently detected insecticide metabolites [other than 3-phenoxybenzoic acid (3-PBA)] were significantly associated with elevated levels of the three OSBs (8-OHdG, 8-OHG, and HNE-MA), where the percent change (Δ%) ranged 8.10-36.0% for 8-OHdG, 8.49-34.7% for 8-OHG, and 5.92-182% for HNE-MA, respectively, with each interquartile ratio (IQR)-fold increase in the concentrations of the individual exposure biomarkers. Weighted quantile sum models demonstrated that the insecticide metabolite mixture was positively associated with the three OSBs. Overall, urinary desmethyl-clothianidin (DM-CLO) and 3,5,6-trichloro-2-pyridinol (TCPy) were the top insecticide exposure biomarkers contributing to the association with 8-OHdG and 8-OHG levels, while PNP contributed the most to the association with HNE-MA levels. These findings suggested that gestational exposure to organophosphates, pyrethroids, neonicotinoids, their transformation products, and their mixture may increase oxidative damage to lipids, RNA, and DNA during pregnancy.

Biomonitoring of glyphosate and aminomethylphosphonic acid: Current insights and future perspectives

Glyphosate is one of the most widely used herbicides globally, raising concerns about its potential impact on human health. Biomonitoring studies play a crucial role in assessing human exposure to glyphosate and providing valuable insights into its distribution and metabolism in the body. This review aims to summarize the current trends and future perspectives in biomonitoring of glyphosate and its major degradation product of aminomethylphosphonic acid (AMPA). A comprehensive literature search was conducted, focusing on studies published between January 2000 and December 2022. The findings demonstrated that glyphosate and AMPA have been reported in different human specimens with urine as the dominance. Sample pretreatment techniques of solid-phase and liquid-liquid extractions coupled with liquid/gas chromatography-tandem mass spectrometry have achieved matrix elimination and accurate analysis. We also examined and compared the exposure characteristics of these compounds among different regions and various populations, with significantly higher levels of glyphosate and AMPA observed in Asian populations and among occupational groups. The median urinary concentration of glyphosate in children was 0.54 ng/mL, which was relatively higher than those in women (0.28 ng/mL) and adults (0.12 ng/mL). It is worth noting that children may exhibit increased susceptibility to glyphosate exposure or have different exposure patterns compared to women and adults. A number of important perspectives were proposed in order to further facilitate the understanding of health effects of glyphosate and AMPA, which include, but are not limited to, method standardization, combined exposure assessment, attention for vulnerable populations, long-term exposure effects and risk communication and public awareness.

Exposure levels and health implications of fungicides, neonicotinoid insecticides, triazine herbicides and their associated metabolites in pregnant women and men

Exposure to pesticides can pose a series of advance effects on human health. However, the exposure levels and health implications of the current use pesticides and their metabolites in both men and pregnant women remain unclear. In this study, an analytical method was developed to quantify fungicides, neonicotinoid insecticides, triazine herbicides, and their metabolites in the human serum. Fifty of the 73 target pesticides and metabolites were detected in the human serum of men and pregnant women from Wuxi, China, which included 11 triazine herbicides and metabolites, 17 neonicotinoid insecticides and metabolites, and 22 fungicides. Fungicides had the highest cumulative concentration (49.5 ng/mL), followed by neonicotinoid insecticides and metabolites (6.38 ng/mL), and triazine herbicides and metabolites (5.10 ng/mL). Moreover, the estimated daily intake (EDI) of fungicides was 10.4 and 12.7 times higher than that of triazine herbicides (included their metabolites) and neonicotinoid insecticides (included their metabolites), respectively. Of the three categories of pesticides, exposure to fungicides contributed to the highest exposure risk within the hazard quotient in the range of 5.1 × 10-3-0.17. Correlation analysis revealed that the pesticide exposure levels in human serum were correlated with their maximum residue levels in vegetables and fruits. Pesticide exposure has also been correlated with the weight and Body Mass Index (BMI) of humans based on structural equation modeling. This study provides new insights into the exposure of men and pregnant women to a cocktail of fungicides, neonicotinoid insecticides, triazine herbicides and their metabolites.

Pesticide residues in adults living near a bioenergy plant with 85,000 tons of contaminated wetcake

Neonicotinoid insecticide use is on the rise worldwide due to its broad-spectrum insecticidal action and exclusive approach of neurotoxic action. Besides application during the cultivation of several crops, all seed companies coat their seeds with neonicotinoids to have increased protection against insects during germination. Despite reduced mammalian toxicity, neonicotinoids have harmful effects on non-target non-mammalian organisms such as bees, an essential part of maintaining the ecosystem. In addition, epidemiologic studies have linked human exposure to neonicotinoids with poor developmental and neurological outcomes. Starting in 2015, the AltEn bioenergy plant near Mead, Nebraska, USA, used coated seeds for their ethanol production and failed to properly dispose of byproducts, causing environmental contamination that still exists. This pilot study reports the human urinary levels of neonicotinoids in samples collected during 2022-2023 in the population living in areas close to this now-closed bioenergy plant. Our results show that approximately 30% of the urine samples are contaminated with at least one of the targeted neonicotinoids or their transformed products. The most frequently detected parent neonicotinoid was clothianidin, which accounts for 13% of the samples. However, 5-hydroxy-imidacloprid, the transformed imidacloprid product, is detected in 27% of the samples, ranging from 1.2 to 42 ng/mL. In conclusion, the environmental contamination near Mead, Nebraska, due to improper storage and disposal of highly contaminated byproducts, puts the nearby population at risk from continuous exposure to neonicotinoids through air and dust particles and possible water contamination.

Association between maternal urinary neonicotinoid concentrations and child development in the Japan Environment and Children's Study

BACKGROUND

Recent studies have reported the effect of neonicotinoid (NEO) exposures on development in human. However, information about the risk of childhood development delays due to NEO exposures is limited.

OBJECTIVES

The study aimed to examine the association between NEO exposure and child development up to 4 years of age using data of the Japan Environment and Children's Study.

METHODS

The study employed urinary NEO and metabolite concentrations in the first and second or third trimesters; the Japanese translation of the Ages and Stages Questionnaire (third edition; J-ASQ-3) scores on developmental delay in five domains, namely communication, gross motor skills, fine motor skills, problem solving, and personal-social characteristics from 6 months to 4 years of age; and self-reported questionnaire data. The associations between urinary NEO concentrations and J-ASQ-3 results were analysed using the treed distributed lag mixture model. A total of 8538 participants were included in statistical analyses.

RESULTS

The determination rates of urinary acetamiprid-N-desmethyl (dm-ACE), clothianidin (CLO), dinotefuran (DIN) and thiamethoxam (THX) were greater than 50%. Median urinary dm-ACE, CLO, DIN and THX concentrations were 0.34, 0.14, 0.22 and 0.05 ng/ml, respectively, in samples collected during gestational weeks < 23, and 0.28, 0.12, 0.18 and 0.04 ng/ml, respectively, in those collected during gestational weeks ≥ 23. The binomial scores divided by the cut-off values of the J-ASQ were used in the treed distributed lag mixture model. The highest percentage for a domain with a value less than the cut-off value was 'problem solving' at 6 months of age among all the J-ASQ-3 scores (10.5%). There was no statistically significant association between maternal urinary dm-ACE, CLO, DIN and THX concentrations during pregnancy and the J-ASQ-3 results up to 4 years of age. Objective assessment of child development in different populations may be warranted to confirm our findings.

MtDNA Copy Number in Oral Epithelial Cells Serves as a Potential Biomarker of Mitochondrial Damage by Neonicotinoid Exposure: A Cross-Sectional Study

As the mitochondrial DNA copy number (mtDNAcn) has been reported to be a biomarker for mtDNA damage in honeybees when exposed to sublethal neonicotinoids, the feasibility of using human mitochondria as a predictor upon neonicotinoid exposure remains elusive. This study investigated the association between the urinary neonicotinoid and the relative mtDNAcn (RmtDNAcn) of oral epithelial cells collected in a cross-sectional study with repeated measurements over 6 weeks. The molecular mechanism underlying neonicotinoid-caused mitochondrial damage was also examined by in vitro assay. Herein, the average integrated urinary neonicotinoid (IMIRPF) concentration ranged from 8.01 to 13.70 μg/L (specific gravity-adjusted) during the sampling period. Concomitantly, with an increase in the urinary IMIRPF, the RmtDNAcn significantly increased from 1.20 (low group) to 1.93 (high group), indicating potential dose-dependent mitochondrial damage. Furthermore, the linear regression analysis confirmed the significant correlation between the IMIRPF and RmtDNAcn. Results from in vitro assays demonstrated that neonicotinoid exposure led to the inhibition of the genes encoding mitochondrial oxidative phosphorylation (OXPHOS) complexes I and III (e.g., ND2, ND6, CytB, and CYC1), accompanied by increased reactive oxygen species production in SH-SY5Y cells. Conjointly, neonicotinoid exposure led to mitochondrial dysfunction and a resulting increase in the RmtDNAcn, which may serve as a plausible biomarker in humans.

Exposure to multiple neonicotinoid insecticides, oxidative stress, and gestational diabetes mellitus: Association and potential mediation analyses

As the most extensively used insecticides worldwide, neonicotinoid insecticides (NNIs) have received a growing global concern over their adverse health effects. This study aimed to assess the associations of urinary concentrations of NNIs in early pregnancy with gestational diabetes mellitus (GDM) and the mediation roles of oxidative DNA damage, RNA damage, and lipid peroxidation in the associations. With a prospective nested case-control study, 519 GDM cases and 519 controls were matched on the infant's sex and maternal age. Urinary biomarkers of NNIs exposure and oxidative stress were measured in early pregnancy. We estimated the associations of single and the mixture of NNIs and their metabolites with GDM by conditional logistic regression and quantile g-computation models, respectively. The mediating roles of oxidative stress were evaluated by the structural equation model. The odds of GDM significantly increased by 15 %, 18 %, 26 %, 42 %, 49 %, and 13 % in each unit increment of ln-transformed concentrations of urinary imidacloprid (IMI), imidacloprid-olefin (IMI-olefin), desnitro-imidacloprid (DN-IMI), thiamethoxam (THM), clothianidin, and desmethyl-clothianidin, respectively. Exposure to the mixture of NNIs was associated with increased odds of GDM (adjusted OR: 1.76; 95 %CI: 1.45, 2.13). Advanced maternal age enhanced the associations of 5-hydroxy-IMI, DN-IMI, and IMI-olefin with GDM (P < 0.05), and being overweight/obese before pregnancy strengthened the effects of IMI, IMI-olefin, and THM on GDM (P < 0.05). In the association of NNIs exposure and GDM, the proportions mediated by oxidative DNA damage, RNA damage, and overall oxidative stress were 9.8 %, 11.8 %, and 14.5 %, respectively (P < 0.05). Exposure to individual NNIs and a mixture of NNIs were associated with GDM, and maternal age and pre-pregnancy BMI may modify the association. The possible mechanism underlying the association between NNIs and GDM may involve oxidative damage to nucleic acids.

Neonicotinoid insecticides and their metabolites: Specimens tested, analytical methods and exposure characteristics in humans

The use of neonicotinoid insecticides (NEOs) has been rising globally due to their broad-spectrum insecticidal activity, unique mode of neurotoxic action and presumed low mammalian toxicity. Given their growing ubiquity in the environment and neurological toxicity to non-target mammals, human exposure to NEOs is flourishing and now becomes a big issue. In the present work, we demonstrated that 20 NEOs and their metabolites have been reported in different human specimens with urine, blood and hair as the dominance. Sample pretreatment techniques of solid-phase and liquid-liquid extractions coupled with high performance liquid chromatography-tandem mass spectrometry have successfully achieved matrix elimination and accurate analysis. We also discussed and compared exposure characteristics of these compounds among types of specimens and different regions. A number of important knowledge gaps were also identified in order to further facilitate the understanding of health effects of NEO insecticides, which include, but are not limited to, identification and use of neuro-related human biological samples for better elucidating neurotoxic action of NEO insecticides, adoption of advanced non-target screening analysis for a whole picture in human exposure, and expanding investigations to cover non-explored but NEO-used regions and vulnerable populations.

Urinary neonicotinoid insecticides and adiposity measures among 7-year-old children in northern China: A cross-sectional study

BACKGROUND

Neonicotinoid insecticides (NEOs) are emerging synthetic insecticides used in various pest management regimens worldwide. Toxicology studies have indicated the obesogenic potential of NEOs, but their associations with adiposity measures are largely unknown.

OBJECTIVES

We aimed to assess urinary levels of NEOs/metabolites and their associations with children's adiposity measures, and to further investigate the potential role of oxidative stress.

METHODS

This study included 380 children who participated in the 7th year's follow-up of the Laizhou Wan Birth Cohort in northern China. Urinary levels of seven NEOs and two metabolites and a biomarker of lipid peroxidation named 8-iso-prostaglandin-F2α (8-iso-PGF2α) were detected. A total of nine indicators of adiposity were measured. Body mass index (BMI) z-score ≥85th percentile was defined as overweight/obesity, and waist-to-height ratio (WHtR) ≥0.5 was considered as abdominal obesity. Multiple linear regression, binary logistic regression and mediation analysis were performed.

RESULTS

Six NEOs [imidacloprid (IMI, 99.7%), clothianidin (CLO, 98.9%), dinotefuran (DIN, 97.6%), thiamethoxam (THM, 95.5%), acetamiprid (ACE, 82.9%), thiacloprid (THD, 77.6%)] and two metabolites [N-desmethyl-acetamiprid (N-DMA, 100.0%), 6-chloronicotinic acid (6-CINA, 97.9%)] exhibited high detection rates. Multiple linear regressions showed positive associations of waist circumference with urinary levels of IMI and THM, of WHtR with IMI and THM levels, and of body fat percentage with 6-CINA levels. In contrast, exposure to N-DMA was negatively associated with body fat percentage and fat mass index. Binary logistic regressions further revealed that higher IMI levels were associated with overweight/obesity (OR = 1.556, 95% CI: 1.100, 2.201) and abdominal obesity (OR = 1.478, 95% CI: 1.078, 2.026) in children. 8-iso-PGF2α demonstrated 27.92%, 69.52% and 35.37% mediating effects in the positive associations of IMI, THD and THM with WHtR, respectively. Sex modified the associations of DIN with body fat mass (p_int = 0.032), body fat percentage (p_int = 0.009), fat mass index (p_int = 0.037) and the overweight/obesity rate (p_int = 0.046), with negative associations in girls and nonsignificant positive associations in boys.

CONCLUSIONS

School-age children in northern China were widely exposed to NEOs/metabolites. Urinary levels of NEOs/metabolites were associated with adiposity measures through the mediating role of 8-iso-PGF2α. These associations were mixed, and a sex-specific effect might exist.

Infantile Internal and External Exposure to Neonicotinoid Insecticides: A Comparison of Levels across Various Sources

Little is known about exposure of infants to neonicotinoid insecticides (NEOs). In this study, concentrations of six parent NEOs (p-NEOs) and N-desmethyl-acetamiprid (N-dm-ACE) were measured in urine and whole blood samples from infants, in addition to breast milk, infant formula, and tap water collected in South China. The p-NEO with the highest median concentration in urine (0.25 ng/mL) and blood (1.30) samples was dinotefuran (DIN), while imidacloprid (IMI) was abundant in breast milk (median: 0.27 ng/mL), infant formula (0.22), and tap water (0.028). The older infants (181-360 days) might face higher NEO and N-dm-ACE exposure than younger infants (0-180 days). Blood samples contained a significantly (p < 0.01) higher median concentration of ∑₆p-NEOs (2.03 ng/mL) than that of urine samples (0.41), similar to acetamiprid (ACE), IMI, thiacloprid (THD), DIN, and N-dm-ACE, suggesting that NEOs readily partition into blood. Furthermore, breast-fed infants tend to have higher exposure levels than formula-fed infants. Infant formula prepared with tap water augmented the daily intake of ∑NEOs. The external sources contributed 80% of the total dose to IMI and clothianidin (CLO) exposure, while other unknown sources contributed to ACE, THD, and DIN exposure in infants. To the best of our knowledge, this is the first study to assess levels and sources of infantile exposure to NEOs through internal and external exposure assessment.

Prevalence of neonicotinoid insecticides in paired private-well tap water and human urine samples in a region of intense agriculture overlying vulnerable aquifers in eastern Iowa

A pilot study among farming households in eastern Iowa was conducted to assess human exposure to neonicotinoids (NEOs). The study was in a region with intense crop and livestock production and where groundwater is vulnerable to surface-applied contaminants. In addition to paired outdoor (hydrant) water and indoor (tap) water samples from private wells, urine samples were collected from 47 adult male pesticide applicators along with the completions of dietary and occupational surveys. Estimated Daily Intake (EDI) were then calculated to examine exposures for different aged family members. NEOs were detected in 53% of outdoor and 55% of indoor samples, with two or more NEOs in 13% of samples. Clothianidin was the most frequently detected NEO in water samples. Human exposure was ubiquitous in urine samples. A median of 10 different NEOs and/or metabolites were detected in urine, with clothianidin, nitenpyram, thiamethoxam, 6-chloronicotinic acid, and thiacloprid amide detected in every urine samples analyzed. Dinotefuran, imidaclothiz, acetamiprid-N-desmethyl, and N-desmethyl thiamethoxam were found in ≥70% of urine samples. Observed water intake for study participants and EDIs were below the chronic reference doses (CRfD) and acceptable daily intake (ADI) standards for all NEOs indicating minimal risk from ingestion of tap water. The study results indicate that while the consumption of private well tap water provides a human exposure pathway, the companion urine results provide evidence that diet and/or other exposure pathways (e.g., occupational, house dust) may contribute to exposure more than water contamination. Further biomonitoring research is needed to better understand the scale of human exposure from different sources.

Urinary Biomarkers and Point-of-Care Urinalysis Devices for Early Diagnosis and Management of Disease: A Review

Biosensing and microfluidics technologies are transforming diagnostic medicine by accurately detecting biomolecules in biological samples. Urine is a promising biological fluid for diagnostics due to its noninvasive collection and wide range of diagnostic biomarkers. Point-of-care urinalysis, which integrates biosensing and microfluidics, has the potential to bring affordable and rapid diagnostics into the home to continuing monitoring, but challenges still remain. As such, this review aims to provide an overview of biomarkers that are or could be used to diagnose and monitor diseases, including cancer, cardiovascular diseases, kidney diseases, and neurodegenerative disorders, such as Alzheimer’s disease. Additionally, the different materials and techniques for the fabrication of microfluidic structures along with the biosensing technologies often used to detect and quantify biological molecules and organisms are reviewed. Ultimately, this review discusses the current state of point-of-care urinalysis devices and highlights the potential of these technologies to improve patient outcomes. Traditional point-of-care urinalysis devices require the manual collection of urine, which may be unpleasant, cumbersome, or prone to errors. To overcome this issue, the toilet itself can be used as an alternative specimen collection and urinalysis device. This review then presents several smart toilet systems and incorporated sanitary devices for this purpose.

First evidence of neonicotinoid insecticides in human bile and associated hepatotoxicity risk

Neonicotinoids (NEOs) are widely applied in agricultural lands and are widespread in different environments, accelerating threats to ecosystems and human health. A number of in vitro/in vivo studies have reported adverse effects of NEOs on mammalian health, but the link between NEO exposure and toxic effects on human liver remains unclear. We randomly recruited 201 participants and quantified eight commercialized NEOs in bile. High frequency and concentration of detection indicate low degradation of human liver on NEOs. The main NEOs are nitenpyram and dinotefuran, which contribute to about 86% of the total residual levels of eight NEOs, due to the highest solubility in bile and are not degraded easily in liver. In contrast, imidacloprid and thiacloprid are major compounds in human blood, according to previous studies, suggesting that individual NEOs behave differently in blood and bile distribution. There was no statistical difference in NEO residues between cancer and non-cancer participants and among the different participant demographics (e.g., age, gender, and body mass index). The serum hematological parameters -bile acid, total bilirubin, cholesterol and alkaline phosphatase -were positively correlated with individual NEO concentrations, suggesting that NEO exposure affects liver metabolism and even enterohepatic circulation. The study first examined the NEO residues in human bile and provided new insights into their bioavailability and hepatoxicity risk.

A simultaneous, high-throughput and sensitive method for analysing 13 neonicotinoids and metabolites in urine using a liquid chromatography-tandem mass spectrometry

A simultaneous, high-throughput and sensitive method for analysing nine neonicotinoid pesticides (NEOs) and four metabolites (NEOms) in urine using a liquid chromatography-tandem mass spectrometry (LC-MSMS) was developed. The method detection limit (MDL) and lowest concentration minimum reporting limit (LCMRL) of the nine NEOs were 0.0013-0.048 ng/ml and 0.0050-0.17 ng/ml, respectively. The MDL and LCMRL of the four NEOms were 0.0052-0.52 ng/ml and 0.011-1.6 ng/ml, respectively. Intermediate precision for the nine NEOs and four NEOms was 7.5-12.5% and 7.4-10.9%, respectively. Accuracy for the nine NEOs and four NEOms was 3.83-5.60% and 3.01-29.2%, respectively. The developed method was applied to analyse urine samples collected from participants of a large-scale birth cohort study, namely, the Japan Environment and Children's Study (JECS). •The NEO and NEOm concentrations in 100 µl urine samples were analysed using a highly sensitive LC-MSMS.•Automated solid phase extraction in a 96-well plate was utilised to achieve high-throughput analysis.•Intermediate precision and accuracy were less than 12.5% and 94.8-99.1%, respectively.

Pesticides monitoring in biological fluids: Mapping the gaps in analytical strategies

Pesticides play a key-role in the development of the agrifood sector allowing controlling pest growth and, thus, improving the production rates. Pesticides chemical stability is responsible of their persistency in environmental matrices leading to bioaccumulation in animal tissues and hazardous several effects on living organisms. The studies regarding long-term effects of pesticides exposure and their toxicity are still limited to few studies focusing on over-exposed populations, but no extensive dataset is currently available. Pesticides biomonitoring relies mainly on chromatographic techniques coupled with mass spectrometry, whose large-scale application is often limited by feasibility constraints (costs, time, etc.). On the contrary, chemical sensors allow rapid, in-situ screening. Several sensors were designed for the detection of pesticides in environmental matrices, but their application in biological fluids needs to be further explored. Aiming at contributing to the implementation of pesticides biomonitoring methods, we mapped the main gaps between screening and chromatographic methods. Our overview focuses on the recent advances (2016-2021) in analytical methods for the determination of commercial pesticides in human biological fluids and provides guidelines for their application.

Occurrence of emerging bisphenol S analogues in urine from five occupational populations in South China

Bisphenol S (BPS) and its 11 emerging analogues were investigated in 325 urine samples from five occupational populations in South China. Besides BPS, ten emerging BPS analogues were newly identified and detected in the urine. It should be noted that urinary concentrations of dominant BPS analogues of 2,4'-bis(hydroxyphenyl)sulfone (2,4-BPS), bis(3-allyl-4-hydroxyphenyl)sulfone (TGSA) and diphenylsulfone (DPS) were 1.1-2.3 times higher than that of BPS, with overall detection frequencies at 74-91 %. The median sum concentrations of the target 12 bisphenols (ng/mL) were found highest in urine from cashiers (1.12), followed by water plant staffs (0.994), teachers (0.552), doctors (0.408) and power plant staffs (0.333). The composition profile of the urinary dominant bisphenols was occupational-dependent, with 2,4-BPS accounting for 45-73 % in cashiers and power plant staffs, and with DPS and TGSA for 74-82 % among doctors, teachers and water plant staffs. Significant correlations were found among the most frequently detected bisphenols in cashiers, indicating their common application and emission pathways. The median exposures based on estimated daily intakes (EDIs, ng/kg bw/day) for the 12 bisphenols in cashiers and water plant staffs (31.6-35.6) were 1.8-3.4 times higher than those of teachers, doctors and power plant staffs (10.6-17.5). This is the first study to identify multiple emerging BPS analogues in urine from occupational populations, especially cashiers and water plant staffs.

Organophosphate ester exposure among Chinese waste incinerator workers: Urinary levels, risk assessment and associations with oxidative stress

Organophosphate esters (OPEs), which are frequently used as flame retardants and plasticizers in versatile products, are readily released to the external environment. Although workers at municipal waste incineration plants may be extensively exposed to OPEs, only scarce health monitoring and risk assessments have been conducted in this population. In this study, we investigated the levels of eight metabolites of organophosphate esters (mOPEs) and the oxidative stress marker 8-hydroxy-2-deoxyguanosine (8-OHdG) in urine samples from 73 waste incinerator workers and 97 general residents from Shenzhen, China between September 2016 and June 2017. The overall detection rate of mOPEs was 82.2 %-100 %, and higher concentrations of di-p-cresyl phosphate and chlorinated mOPEs [bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2propyl) phosphate (BCIPP), bis(1,3-dichloro-2-propyl) phosphate) (BDCIPP)] were found among incinerator workers than among general residents. The incinerator workers also showed significantly higher levels of 8-OHdG than general residents, but the measured levels of most mOPEs were not significantly correlated with the level of 8-OHdG; this may be because co-exposure to multiple toxic compounds can lead to oxidative stress. Risk assessment using Monte Carlo simulations revealed that 95 % of the incinerator workers were free from non-carcinogenic effects due to OPEs exposure (hazard index = 0.27, 95 % CI: 0.09, 0.77). However, the carcinogenic risk of tris(2-chloroethyl) phosphate (TCEP) for incinerator workers was between 10-6 and 10-4. These results indicate that incinerator workers are extensively exposed to OPEs, and better protective measures need to be implemented.

Neonicotinoid Insecticides and Their Metabolites Can Pass through the Human Placenta Unimpeded

Studies on neonicotinoid (NEO) exposure in pregnant women and fetuses are scarce, and transplacental transfer of these insecticides is unknown. In this study, parent NEOs (p-NEOs) and their metabolites (m-NEOs) were determined in 95 paired maternal (MS) and cord serum (CS) samples collected in southern China. Imidacloprid was the predominant p-NEO in both CS and MS samples, found at median concentrations of 1.84 and 0.79 ng/mL, respectively, whereas N-desmethyl-acetamiprid was the most abundant m-NEO in CS (median: 0.083 ng/mL) and MS (0.13 ng/mL). The median transplacental transfer efficiencies (TTEs) of p-NEOs and m-NEOs were high, ranging from 0.81 (thiamethoxam, THM) to 1.61 (olefin-imidacloprid, of-IMI), indicating efficient placental transfer of these insecticides. Moreover, transplacental transport of NEOs appears to be passive and structure-dependent: cyanoamidine NEOs such as acetamiprid and thiacloprid had higher TTE values than the nitroguanidine NEOs, namely, clothianidin and THM. Multilinear regression analysis revealed that the concentrations of several NEOs in MS were associated significantly with hematological parameters related to hepatotoxicity and renal toxicity. To our knowledge, this is the first analysis of the occurrence and distribution of NEOs in paired maternal-fetal serum samples.

Daily Variability in Urinary Artificial Sweeteners and Its Association with Oxidative Stress Biomarkers

Urinary artificial sweeteners (ASs) have been proved to be useful biomarkers for assessing their dietary intakes; however, it is unclear how well a spot urine sample may represent a longer-term exposure. Therefore, a longitudinal study was designed and six ASs and two oxidative stress biomarkers, namely, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA), were determined. Acesulfame (ACE) and saccharin (SAC) were detected in most urines with concentration ranges of Collapse

Key Words

• artificial sweeteners
• exposure assessment
• human biomonitoring
• oxidative stress biomarkers
• variability

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MESH Headings

• Humans
• 8-Hydroxy-2'-Deoxyguanosine
• Biomarkers/urine
• Deoxyguanosine
• Longitudinal Studies
• Oxidative Stress
• Saccharin
• Sweetening Agents

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Grants Collapse

Affiliation(s)

Yumeng Shi MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Hongkai Zhu MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Fei Wang Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
Shucong Chen MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Ke Xu MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Lei Wang MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
Hongwen Sun MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China

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An assessment of exposure to several classes of pesticides in pet dogs and cats from New York, United States

Exposure of pet dogs and cats to pesticides used in and around homes (e.g., lawns and gardens) is a significant health concern. Furthermore, some pesticides are directly used on dogs and cats for flea, lice, and tick control. Despite this, little is known regarding the extent of pesticide exposure in pets. In this study, we determined the concentrations of 30 biomarkers of pesticide exposure in urine collected from dogs and cats in New York State, USA: 6 dialkylphosphate (DAP) metabolites of organophosphates (OPs); 14 neonicotinoids (neonics); 3 specific metabolites of OPs; 5 pyrethroids (PYRs); and 2 phenoxy acids (PAs). The sum median concentrations of these 30 pesticide biomarkers (ΣPesticides) in dog and cat urine were 35.2 and 38.1 ng/mL, respectively. Neonics were the most prevalent in dogs (accounting for 43% of the total concentrations), followed by DAPs (17%), PYRs (16%), OPs (13%), and PAs (∼10%). In cat urine, neonics alone accounted for 83% of the total concentrations. Elevated concentrations of imidacloprid were found in the urine of certain dogs (max: 115 ng/mL) and cats (max: 1090 ng/mL). Some pesticides showed gender- and sampling location- related differences in urinary concentrations. We calculated daily exposure doses of pesticides from the measured urinary concentrations through a reverse dosimetry approach. The estimated daily intakes (DIs) of chlorpyrifos, diazinon, and cypermethrin were above the chronic reference doses (cRfDs) in 22, 76, and 5%, respectively, of dogs. The DIs of chlorpyrifos, parathion, diazinon, and imidacloprid were above the cRfDs in 33, 14, 100, and 29%, respectively, of cats. This study thus provides evidence that pet dogs and cats are exposed to certain pesticides at levels that warrant immediate attention.

Variability of urinary biomarkers of neonicotinoid insecticides in Chinese population: Implications for human exposure assessment

Neonicotinoids are a class of the most widely used insecticides worldwide with a short biological half-life. The levels of neonicotinoids and their metabolites in urine have been detected as biomarkers for human exposure assessment. To understand the reliability of a single measurement of urinary neonicotinoid biomarkers in representing a true longer-term average exposure, in this study we evaluated the temporal variability of 14 neonicotinoids and/or their metabolites over one year in 114 Chinese young adults. The detection rates of 14 neonicotinoid biomarkers ranged from 18% to 100%. The intraclass correlation coefficients (ICCs) of most neonicotinoid biomarkers indicated poor (ICC <0.4) reproducibility in spot urine samples during 1-week, 1-month, or 1-year periods, except for 5-hydroxy-imidacloprid (5-OH-IMI) within 1-week showing fair to good reproducibility (ICC = 0.40). Log-transformed 5-OH-IMI, dinotefuran, 1-methyl-3-(tetrahydro-3-furylmethyl) urea, N-desmethyl-acetamiprid, and N-desmethyl-thiamethoxam required a minimum of 2-4 spot urine samples over one year to obtain a reliable exposure evaluation. Using two or three spot urine samples to categorize the "true" exposure of the highest tertile indicated the higher specificities (0.60-1.00) than the sensitivities (0.24-0.93). We recommend that at least 2-4 spot urine samples are used to assess 1-year neonicotinoid exposure and seasonal variations should be considered when scheduling urine sample collection. This study provides a reference for appropriate sampling method and research design for the exposure assessment of neonicotinoids in biomonitoring and epidemiological studies.

A high-throughput microplate toxicity screening platform based on Caenorhabditis elegans

Caenorhabditis elegans (C. elegans), an established model organism, has been widely used in environmental toxicology research. However, most of the current toxicity testing methods based on worms are time-consuming. In this study we aimed to develop an automated and highly-integrated platform for high-throughput and in situ toxicity testing. Considering the superiority of C. elegans as a neurotoxicological model, this platform mainly evaluates general toxicology and neurotoxicology endpoints, which are usually induced by metals and pesticides, the major environmental contaminants. Microplates were used as a worm culturing system, which have good compatibility with any commercial microplate applicable instruments. We developed a microfluidic-based module for worm dispensing, and an image acquisition/analysis module for monitoring worms and detecting toxicity endpoints in bright filed. These were collectively incorporated with a commercial pipetting workstation for automated food/drug delivery and a high-content analysis system for fluorescence detection. The integrated platform achieved an efficient on-demand worm dispensing, long-term maintenance, regular monitoring and imaging, survival assay and behavioral analyses, and visualized gene reporter assay. Moreover, "Lab on Web" was achieved by connecting the platform to the web for remote operation, worm monitoring, and phenotype calculation. To demonstrate the ability of the platform for automated toxicity testing assays; worms were treated with cadmium and longevity, neurotoxicity, developmental toxicity and gst-4 expression were evaluated. We determined its feasibility and proposed the potential application in high-throughput toxicity screening for environmental risk assessment in the nearest future.

Variability in urinary concentrations of primary aromatic amines

Despite their known carcinogenic potential, primary aromatic amines (AAs) continue to be used in various consumer products. Human exposure to AAs is a subject of current concern. Although urinary measurements are used in the assessment of exposure, little is known about within- and between-individual temporal variability in urinary concentrations of AAs. In this study, we determined the concentrations of 30 AAs, nicotine and cotinine in 213 first morning void (FMV) urine samples collected longitudinally for over a five-week period from 15 participants residing in the Albany area of New York State, USA. Eight AAs, namely, aniline, 2-naphthylamine (2-NA), p-cresidine (p-CD), p-toluidine (p-TD), o/m-toluidine (o/m-TD), 4-chloroaniline (4-CA), 4,4'-methylenedi-o-toluidine (4,4'-MDA), and 2,6-dimethylaniline (2,6-DMA) were found in urine at a detection frequency (DF) in the range of 68-100%. Aniline and 2,6-DMA were the predominant compounds found at median concentrations of 6.0 and 3.81 ng/mL, respectively. Intraclass correlation coefficients (ICCs) of all urinary AA concentrations, except for 4-CA, showed moderate to poor predictability (ICC values ranged 0.248-0.697). Gender and ethnicity-related variations in ∑₈AA concentrations were significant. Spearman's correlations among AA concentrations suggested that the sources of exposure were not related to tobacco smoke. No significant correlations existed between AAs concentrations and oxidative stress biomarkers (OSBs). The estimated daily intakes of AAs calculated based on urinary concentrations were several orders of magnitude below the tolerable daily intakes.

Inference of emission history of neonicotinoid pesticides from marine sediment cores impacted by riverine runoff of a developed agricultural region: The Pearl River Basin, China

Neonicotinoids (NEOs), as the most-consumed pesticides on a global scale, have posed a serious threat to human health and ecological environment. Information regarding the emission history of NEOs is of great importance to improve the prediction of their environmental loading and biological risk potential. In the present study, contamination levels and compositions of 12 NEOs were identified in 8 sediment cores from the Lingdingyang Estuary, which was impacted by agricultural emissions in riverine runoff of the Pearl River Basin for centuries. The total concentration of 12 target NEOs (∑₁₂NEOs) ranged from 0.02 to 69.5 ng/g dw along the sediment core profile, with a mean of 12.9 ± 15.9 ng/g dw. Net deposition fluxes and concentrations of 5 parent NEOs experienced a remarkable exponential increase in the vertical profile of sediment cores, except for imidacloprid (IMI). Despite the similar exponential growth before 2012, subsequent decreased levels of IMI in historical sediment indicated its gradual replacement by other NEOs. IMI was the NEO with the highest frequency of 80.3% and the highest mean concentration of 7.66 ± 8.76 ng/g dw. The ecological risk assessment of NEOs suggests that 65.1% of sediment samples exceeded the chronic threshold for aqueous organisms using equilibrium partitioning approach. Since downward diffusion of NEOs in the Lingdingyang Estuary was rectified by their rapid desorption, the sedimentary record probably provided an accurate illustration of agricultural NEO emissions in the Pearl River Basin, China. The recent NEO inventory in the adjacent waters of core sites was estimated with a mean of 76.8 tons/yr. This study provides insights into the role of agricultural emission in riverine runoff in the environmental loads of NEOs in the historical sediment.

Exposure to neonicotinoid insecticides and their characteristic metabolites: Association with human liver cancer

Neonicotinoid insecticides (NEOs) are commonly applied for pest control in China and around the world. Previous studies reported that NEOs are hepatotoxic to mammals. However, limited studies have explored the associations between NEOs exposure and liver disease. In the present study, we detected six parent NEOs (p-NEOs), including acetamiprid, thiacloprid, dinotefuran, clothianidin, imidacloprid, and thiamethoxam, and five characteristic metabolites (m-NEOs), including 5-hydroxy-imidacloprid, olefin-imidacloprid, N-desmethyl-acetamiprid, 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine and 1-methyl-3-(tetrahydro-3-furyl methyl) urea, in blood samples collected from healthy donors (n = 100; females vs. males: 45 vs. 55; age: 22-91 years) and liver cancer patients (n = 274; females vs. males: 118 vs. 156; age: 11-88 years) in one hospital from Guangzhou city, South China. NEOs were frequently detected (61%-94%) in blood samples, with median concentrations ranging from 0.19 ng/mL to 1.28 ng/mL and 0.20 ng/mL to 2.03 ng/mL for healthy and liver cancer populations, respectively. olefin-imidacloprid was the most abundant NEOs in healthy and liver cancer populations, accounting for 23.4% and 20.7%, respectively. Significant positive correlations among most m-NEOs concentrations were found, and associations between m-NEOs and their corresponding p-NEOs were positively correlated. These findings indicated that the sources of m-NEOs were both endogenous and exogeneous. Females had higher median concentrations of NEOs and their metabolites than males. Moreover, the α-fetoprotein values and blood concentrations of target analytes (r = 0.428-0.601, p < 0.05) were positively correlated. Meanwhile, associations between the concentrations of p-NEOs and m-NEOs and liver cancer were found (odds ratio = 2.33-9.02, 95% confidence interval = 0.31-22.7, p < 0.05), indicating that human exposure to NEOs and their metabolites might increase the odds of liver cancer prevalence. Our work provided a new insight into the hepatotoxicity of NEOs and their metabolites, and human health risks of exposure to these pollutants warranted further studies.

Human exposure to neonicotinoids and the associated health risks: A review

Neonicotinoids (NEOs) are a class of broad-spectrum insecticides dominant in the global market. They were distributed extensively in the environment and occurred frequently in humans. Potential health effects of NEOs, such as neurological toxicity and diabetes to non-targeted mammals, have raised concerns. This review summarizes analytical methods of NEOs in human samples, their internal exposure levels and composition profiles in urine, blood, hair, breast milk, saliva and tooth samples with global comparisons, and daily NEOs exposure dose and relative health risks.Urinary NEOs levels in Asian populations were substantially higher than those in the U.S. and Europe, which may be due to different dietary patterns and insecticide applications across regions. N-desmethyl acetamiprid, 5-hydroxy-imidacloprid and olefin-imidacloprid were dominant among detected NEOs. NEO metabolites exhibited higher detection frequencies and levels than their parent compounds in humans, while investigations on NEO metabolites remain much limited. Current exposure assessments mainly focused on short-term urine analysis, while biomaterials for long-term monitoring, such as hair, nail and other alternatives, should also be considered. Large-scale epidemiological studies are critically needed to elucidate potential health outcomes associated with NEOs exposure.

Urinary neonicotinoid concentrations and pubertal development in Chinese adolescents: A cross-sectional study

BACKGROUND

Animal studies suggest that exposure to certain neonicotinoids may interfere with the normal function of endocrine system in mammals. However, evidence from human studies is limited.

OBJECTIVES

This study conducted a cross-sectional analysis to examine urinary neonicotinoids concentrations in Chinese adolescents and its association with pubertal development.

METHODS

774 urine samples from 439 boys (median age: 13.7 years; 25th-75th percentile: 12.7-14.5 years) and 335 girls (median age: 13.7 years; 25th-75th percentile: 12.7-14.5 years) were collected for determination of ten neonicotinoids (imidacloprid, nitenpyram, acetamiprid, thiacloprid, imidaclothiz, thiamethoxam, clothianidin, dinotefuran, flonicamid, sulfoxaflor) and one metabolite (N-desmethyl-acetamiprid). Urinary creatinine was detected for concentration adjustment. Pubertal development including pubic hair, axillary hair, genitalia (boys), testicular volume (boys) and breast (girls) assessed by Tanner stages and others (spermarche, facial hair for boys and menarche for girls) were obtained by physical examination and questionnaire. Logistic and bayesian kernel machine regression were used to investigate the association between neonicotinoids concentrations and pubertal developments.

RESULTS

High detection rates ranged from 72.0% to 100.0% for all neonicotinoids. Boys and girls with thiacloprid concentration at the >75th percentile had lower stage of genitalia development (OR: 0.83, 95% CI: 0.33-0.93) and higher stage of axillary hair development (OR: 1.46, 95% CI: 1.12-3.41), respectively, compared with those at the <25th percentile. The estimate change in genitalia stage was significantly different at or above the 75th percentile concentration of neonicotinoids mixture compared to the 50th percentile concentration. No associations were found between other urinary neonicotinoids and other indicators of puberty.

CONCLUSIONS

Higher thiacloprid concentration was associated with delayed genitalia development in boys and early axillary hair development in girls. Neonicotinoids mixture was negatively associated with genitalia stage in the joint effect. Given the characteristic of the cross-sectional study, our results need further confirmation of the causal relationship.

Prenatal neonicotinoid insecticides Exposure, oxidative Stress, and birth outcomes

BACKGROUND

An increasing number of studies have reported neonicotinoid insecticides (NEOs), the emerging alternatives to conventional insecticides, may increase oxidative stress and cause adverse health effects, but limited is known about the prenatal NEOs exposures and their impact on birth outcomes.

OBJECTIVES

We investigated the levels of prenatal exposure to NEOs/metabolites, to assess their associations with birth outcomes, and investigate whether these associations could be mediated by oxidative stress using 8-OHdG as the biomarker.

METHODS

We studied 296 mother-infant pairs recruited from Laizhou Wan Birth Cohort in 2010 - 2013. Two NEOs (IMI and ACE), three metabolites (6-CN, ND-ACE, and 2CTCA), and 8-OHdG were measured in maternal urine collected before delivery. Birth outcomes including birth weight, birth length, ponderal index (PI), head circumference, and gestational age, were acquired. We examined the associations between NEOs/metabolites and birth outcomes using multivariable linear regression. Mediation analysis was conducted to clarify the role of 8-OHdG on the association of NEOs/metabolites exposure and birth outcomes.

RESULTS

Highest detection rate was observed for ACE (100.0%), followed by IMI (98.3%) and 6-CN (98.0%), suggesting the common exposure of pregnant women. The highest median concentration was observed for 6-CN with creatinine-adjusted median levels of 9.58 μg/g creatinine. A decrease in newborns' head circumference was observed with a 10-fold increase in IMI (β = -1.83; 95% CI = -3.04, -0.62) and ACE (β = -2.27; 95% CI = -3.56, -0.98). An increase in newborns' PI was observed with a 10-fold increase in IMI (β = 0.40; 95% CI = 0.03, 0.75). Maternal 8-OHdG demonstrated 38.5-65.5% mediating effects in the negative association of IMI, ACE, 2-CTCA with head circumference. These associations might differ between boys and girls.

CONCLUSIONS

Pregnant women were widely exposed to NEOs/metabolites in China. Results suggested the potential impacts of prenatal exposure to certain neonicotinoid insecticides on head circumference. Urinary 8-OHdG may partly mediate these associations.

Exposure assessment of neonicotinoid insecticides and their metabolites in Chinese women during pregnancy: A longitudinal study

Neonicotinoid insecticides (NNIs) are the most widely used insecticides globally and ubiquitous in the environment, which has led to widespread human exposure. However, studies on internal exposure levels of NNIs and their metabolites in pregnant women are scarce. In this study, we measured nine parent NNIs and ten main metabolites in 1224 urine samples donated by 408 pregnant women at three trimesters. In the urine samples, the unadjusted vs. specific gravity (SG) adjusted median concentrations and detection frequencies (DFs) of desmethyl-acetamiprid (DM-ACE; 1.01 vs. 1.08 ng/mL; DF: 99.7%), 5-hydroxy-imidacloprid (5-hydroxy-IMI; 0.54 vs. 0.56 ng/mL; 98.5%), imidacloprid-olefin (IMI-olefin; 0.41 vs. 0.44 ng/mL; 99.3%), and desnitro-imidacloprid (DN-IMI; 0.12 vs. 0.12 ng/mL; 90.4%) were higher than their corresponding parent NNIs, acetamiprid (ACE; <0.01 vs. <0.01 ng/mL; 26.4%) and imidacloprid (IMI; 0.04 vs. 0.04 ng/mL; 69.9%). The unadjusted and SG-adjusted median concentrations of clothianidin (CLO), thiamethoxam (THM), and desmethyl-clothianidin (DM-CLO) were 0.05 vs. 0.07, 0.05 vs. 0.06, and 0.04 vs. 0.05 ng/mL, with the DFs of 61.0%, 57.5%, and 75.7%, respectively. The cumulative exposure level, imidacloprid-equivalent total NNIs (IMI_eq), was generated by the relative potency factor approach considering the toxic effects of NNIs and their metabolites. The unadjusted IMI_eq varied from 0.17 ng/mL (SG-adjusted: 0.20) to 1969 ng/mL (SG-adjusted: 1817) with a median of 14.1 ng/mL (SG-adjusted: 14.1). A decreased trend was observed in urinary NNIs and their metabolites throughout the three trimesters. Maternal age, educational level, and household income were related to the concentrations of NNIs and their metabolites. DM-ACE, 5-hydroxy-IMI, and IMI-olefin were significantly lower in winter than in autumn; DN-IMI, THM, CLO, and DM-CLO were significantly higher in both summer and autumn than in winter. The maximum estimated daily intake of IMI_eq [34.8 μg/kg-body weight (bw)/d] was lower than the chronic reference dose of IMI (57 μg/kg-bw/d) currently recommended by the United States Environmental Protection Agency. Human health risk of exposure to NNIs and their main metabolites warranted further studies.

Diurnal variability in urinary volatile organic compound metabolites and its association with oxidative stress biomarkers

Volatile organic compounds (VOCs) are ubiquitous environmental pollutants that are associated with birth defects, leukemia, neurocognitive deficits, reproductive impairment and cancer in humans exposed to these compounds. Exposure to VOCs can be assessed by measuring their metabolites in urine. Little is known, however, about the temporal variability in urinary VOC metabolite (VOCM) concentrations within- and between-individuals. In this study, we determined the variability in the concentrations of 38 VOCMs in urine samples collected from 19 healthy individuals across a period of 44 days. We also measured seven biomarkers of oxidative stress (lipid, protein and DNA damage) in urine to assess the relationship of VOC exposure to oxidative stress. Seventeen VOCMs had detection frequencies (DFs) of >60% in urine, and we limited further data analysis to those compounds. The creatinine-adjusted geometric mean concentrations of VOCMs ranged from 2.70 μg/g to 327 μg/g in spot and 2.60 μg/g to 551 μg/g in first morning void (FMV) urine samples. Calculation of the intra-class correlation coefficients (ICCs) for 17 VOCM concentrations to assess their predictability and repeatability in urinary measurements showed ranges of 0.080-0.425 in spot and 0.050-0.749 in FMV urine samples, revealing notable within-individual variability. Our results suggest that taking only single measurements of VOCM concentrations in urine in epidemiological investigations may lead to exposure misclassification. In addition, VOCM concentrations were significantly and positively correlated with oxidative stress biomarkers. This study thus provides important information for formulating sampling strategies in the biomonitoring of VOC exposure in human populations.

Assessment of ameliorative effects of organic dietary interventions on neonicotinoid exposure rates in a Japanese population

Neonicotinoid insecticides (NNIs) are a popular class of insecticides used in various pest management regimens worldwide. Biomonitoring studies continuously report high exposure rates of NNIs in various human populations across the globe. Yet, there is no validated countermeasure for combating the recent exponential rise in NNI exposure rates observed in human populations. The current study assessed the impacts of organic dietary interventions on NNI exposure rates in a Japanese population. A total of 103 volunteers were recruited into the study. Subjects were either served with Organic diets for 5 and 30 days or conventional diets. A total of 919 repeated urine samples were collected from the participants and then subjected to LC-MS/MS analysis to determine urinary concentrations of 7 NNIs parent compounds and an NNI metabolite. Eight NNIs were detected; with a decreasing detection frequency (%Dfs) pattern; desmethyl-acetamiprid (dm-ACE) (64.96%) > dinotefuran (52.12%), imidacloprid (39.61%) > clothianidin (33.95%) > thiamethoxam (28.51%) > acetamiprid (12.62%) > nitenpyram (5.33%) > thiacloprid (2.83%). Dinotefuran, dm-ACE, and clothianidin recorded the highest concentrations in the subjects. The %Df of NNIs in the 5-days or 30-days organic diet group were lower than those of the conventional diet consumers. The organic diet group showed lower rates of multiple NNI exposures than those of the conventional diet consumers. The mean and median cumulative levels of NNIs (median IMI_eq) were significantly lower in the organic diet group than the conventional diet group (p < 0.0001). The estimated daily intakes (EDIs) of NNIs were higher in adults than children, but less than 1% of NNI cRfDs, except for clothianidin, which exhibited a %cRfD of 1.32 in children. Compared to the conventional diet group, the 5- and 30-day organic dietary intervention showed drastic reductions in NNI EDIs. Findings from the present study give credence to organic dietary interventions as potential ameliorative strategies for NNI exposure rates in human populations.

Urinary neonicotinoid insecticides in children from South China: Concentrations, profiles and influencing factors

Neonicotinoid insecticides can selectively interact with the unique nicotinic acetylcholine receptor subtypes in insects and are considered to be low toxic to mammals. However, there is still insufficient knowledge on human exposure to neonicotinoid insecticides, especially for children. This study aimed to investigate urinary concentrations and profiles of neonicotinoid insecticides in South China children and to analyze potential influencing factors. Six neonicotinoid insecticides, including imidacloprid (IMI), thiamethoxam (THM), acetamiprid (ACE), clothianidin (CLO), thiacloprid (THD) and dinotefuran (DIN), exhibited high detection frequencies (>90%) in urine samples collected from 305 children, suggesting broad exposure in South China children. The median concentrations were determined to be 0.13, 0.21, 0.01, 0.19, 0.002 and 1.64 μg/L, respectively. Among the target neonicotinoids, urinary concentrations of CLO and THM exhibited a significant and positive correlation between each other (p < 0.05), suggesting similar sources of these two chemicals.

Analysis of 19 urinary biomarkers of oxidative stress, nitrative stress, metabolic disorders, and inflammation using liquid chromatography–tandem mass spectrometry

Environmental chemical exposures have been associated with cancer, diabetes, hormonal and immunological disorders, and cardiovascular diseases. Some direct effects of chemical exposure that are precursors to adverse health outcomes, including oxidative stress, nitrative stress, hormonal imbalance, neutrophilia, and eosinophilia, can be assessed through the analysis of biomarkers in urine. In this study, we describe a novel methodology for the determination of 19 biomarkers of health effects: malondialdehyde (MDA), 8-isoprostaglandin-F_2α (8-PGF_2α), 11-β-prostaglandin-F_2α (11-PGF_2α), 15-prostaglandin-F_2α (15-PGF_2α), 8-iso-15-prostaglandin-F_2α (8,15-PGF_2α), 8-hydroxy-2′-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-HdG), 8-hydroxyguanine (8-HG), dityrosine (diY), allantoin (Alla), and two metabolic products of 4-hydroxynonenal (HNE), namely 4-hydroxy-2-nonenal glutathione (HNE-GSH) and 4-hydroxy-2-nonenal mercapturic acid (HNE-MA) (in total, 12 oxidative stress biomarkers, OSBs); 8-nitroguanosine (8-NdG), 8-nitroguanine (8-NG), and 3-nitrotyrosine (NY) (3 nitrative stress biomarkers, NSBs); chlorotyrosine (CY) and bromotyrosine (BY) (2 inflammatory biomarkers); and the advanced glycation end-products (AGEs) N^ε-carboxymethyllysine (CML) and N^ε-carboxyethyllysine (CEL) (2 metabolic disorder biomarkers). Since these biomarkers are trigged by a variety of environmental insults and produced by different biomolecular pathways, their selective and sensitive determination in urine would help broadly elucidate the pathogenesis of diseases mediated by environmental factors.

Multiple neonicotinoids in children's cerebro-spinal fluid, plasma, and urine

BACKGROUND

Neonicotinoids (NN) are selective neurotoxic pesticides that bind to insect but also mammal nicotinic acetycholine receptors (nAChRs). As the most widely used class of insecticides worldwide, they are ubiquitously found in the environment, wildlife, and foods, and thus of special concern for their impacts on the environment and human health. nAChRs are vital to proper brain organization during the prenatal period and play important roles in various motor, emotional, and cognitive functions. Little is known on children's contamination by NN. In a pilot study we tested the hypothesis that children's cerebro-spinal fluid (CSF) can be contaminated by NN.

METHODS

NN were analysed in leftover CSF, blood, and urine samples from children treated for leukaemias and lymphomas and undergoing therapeutic lumbar punctions. We monitored all neonicotinoids approved on the global market and some of their most common metabolites by ultra-high performance liquid chromatography-tandem mass spectrometry.

RESULTS

From August to December 2020, 14 children were consecutively included in the study. Median age was 8 years (range 3-18). All CSF and plasma samples were positive for at least one NN. Nine (64%) CSF samples and 13 (93%) plasma samples contained more than one NN. Thirteen (93%) CSF samples had N-desmethyl-acetamiprid (median concentration 0.0123, range 0.0024-0.1068 ng/mL), the major metabolite of acetamiprid. All but one urine samples were positive for ≥ one NN. A statistically significant linear relationship was found between plasma/urine and CSF N-desmethyl-acetamiprid concentrations.

CONCLUSIONS

We have developed a reliable analytical method that revealed multiple NN and/or their metabolites in children's CSF, plasma, and urine. Our data suggest that contamination by multiple NN is not only an environmental hazard for non-target insects such as bees but also potentially for children.

Serum concentrations of neonicotinoids and their characteristic metabolites in elderly population from South China: Association with osteoporosis

Neonicotinoids (NEOs) are extensively applied in global agricultural production for pest control but have adverse effects on human health. In this study, the concentrations of six NEOs and three characteristic metabolites were investigated by collecting 200 serum samples from an elderly population in China. Results showed that the NEOs and their metabolites were widely detected (89%-98 %) in the serum samples from the osteoporosis (OP) (n = 120) and non-OP (n = 80) population, and their median concentrations ranged from 0.04 ng/mL to 5.99 ng/mL and 0.01 ng/mL to 2.02 ng/mL, respectively. N-desmethyl-acetamiprid (ACE-dm) was the most abundant NEOs in the serum samples. Gender-related differences were found in concentrations of most NEOs and their metabolites in serum, with males having higher target analytes than females. Significantly (p < 0.05) positive correlations were observed among most NEO concentrations, suggesting that exposure source of these substances is common or related. However, associations between the concentrations of characteristic metabolites and their corresponding NEOs were insignificant, probably because the exogenous intake are the primary sources of metabolites of NEOs instead of the internal biotransformation. The associations between NEO concentrations (i.e., ACE-dm, dinotefuran, and olefin-imidacloprid) and OP (OR = 2.33-6.92, 95 % CI = 0.37-16.9, p-trend < 0.05) indicate that NEO exposure is correlated with increased odds of prevalent OP. This study is the first to document the profiles of NEOs and their metabolites in serum samples collected from an elderly population in South China and examine the relationships between NEO exposure and OP.

Associations of neonicotinoids with insulin and glucose homeostasis parameters in US adults: NHANES 2015-2016

Neonicotinoids are replacement insecticides increasingly used for organophosphates, methylcarbamates, and pyrethroids. Experimental evidence suggests neonicotinoids may affect glucose metabolism and insulin secretion through pancreatic β cell dysfunction, oxidative stress, and inflammation. However, no epidemiologic study has investigated neonicotinoids as potential diabetogens. We examined associations between neonicotinoids with insulin and glucose homeostasis parameters among 1381 non-diabetic adults in the National Health and Nutrition Examination Survey (2015-2016). Urinary concentrations of acetamiprid, clothianidin, imidacloprid, N-desmethyl-acetamiprid, and 5-hydroxy-imidacloprid were quantified. Fasting plasma glucose, insulin, and hemoglobin A_1c (HbA_1c) were assessed. Insulin resistance was defined as a homeostatic model assessment of insulin resistance ≥2.5. We used weighted linear and logistic regression to estimate associations between detectable neonicotinoids with insulin and glucose homeostasis parameters compared to non-detectable neonicotinoid concentrations. Weighted detection frequencies for imidacloprid, 5-hydroxy-imidacloprid, and N-desmethyl-acetamiprid were 4.4 %, 21.5 %, and 32.8 %, respectively. Detectable imidacloprid (β = -4.7 μIU/mL, 95 % confidence interval [CI] -8.5, -0.8) and 5-hydroxy-imidacloprid (β = -2.4 μIU/mL, 95 % CI -4.6, -0.2) were associated with lower fasting plasma insulin levels. Individuals with detectable 5-hydroxy-imidacloprid had lower odds of insulin resistance (odds ratio [OR] = 0.3, 95 % CI 0.2, 0.7). We observed evidence of sexually dimorphic associations between N-desmethyl-acetamiprid with glucose (p_int = 0.079) and 5-hydroxy-imidacloprid with HbA_1c (p_int = 0.038), with patterns suggesting positive associations in males and negative associations in females. Associations between 5-hydroxy-imidacloprid and insulin were modified by body mass index (BMI) (p_int = 0.013). We additionally observed age modified associations between 5-hydyroxy-imidacloprid and glucose (p_int = 0.048). Results suggest neonicotinoids may be associated with insulin and glucose homeostasis indices and call for prospective studies to examine the metabolic impact of these replacement insecticides in humans.

Development of an analytical method based on solid-phase extraction and LC-MS/MS for the monitoring of current-use pesticides and their metabolites in human urine

Pyrethroids, organophosphorus pesticides and fipronil have been listed as priority chemicals in human biomonitoring studies because of their wide use and potential health effects in humans. The determination of 13 pesticides, including pyrethroids (deltamethrin, cypermethrin, permethrin, cyfluthrin, bifenthrin), organophosphorus (chlorpyrifos, chlorpyrifos-methyl, and malathion), fipronil, neonicotinoids (imidacloprid, acetamiprid and thiacloprid) and triazole (prothioconazole), together with 13 corresponding metabolites in human urine samples was achieved by solid-phase extraction and analysis by liquid chromatography coupled to tandem mass spectrometry. All targeted compounds, except malathion dicarboxylic acid, were measured with a mean within-accuracy (n = 5) of 71%-114% (RSD: 1%-14%) and between-run (n = 15) accuracy of 80%-118% (RSD: 2%-14%). Limits of quantitation of the targeted analytes ranged from 0.1 to 16 pg/mL. The detection result of urine samples from 25 volunteers indicated that the detection frequencies of 3,5,6-trichloro-2-pyridinol (median: 448 pg/mL), 6-chloropyridine-3-carboxylic acid (median: 193 pg/mL), 2-methyl-3-phenylbenzoic acid (median: 181 pg/mL), 3-phenoxybenzoic acid (median: 99 pg/mL), 2-isopropyl-6-methyl-4-pyrimidinol (median: 77 pg/mL), cyfluthrin (median: 59 pg/mL), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (cis-DCCA, median: 53 pg/mL), trans-DCCA (median: 25 pg/mL), prothioconazole (median: 21 pg/mL), imidacloprid (median: 7 pg/mL), and prothioconazole-desthio (median: 1 pg/mL) were > 50%. The obtained results show that the validated method is suitable for the human biomonitoring of these current-use pesticides and their metabolites.

Urinary concentrations of neonicotinoid insecticides were related to renal tubular dysfunction and neuropsychological complaints in Dry-zone of Sri Lanka

Neonicotinoids are systemic insecticides used since the 1990’s , that possess renal tubular toxicity. We conducted a field-based descriptive study in the North Central Dry-zone of Sri Lanka, where chronic kidney disease (CKD) of unknown etiology has been increasing since the 1990’s. To elucidate the relationship between renal tubular dysfunctions and urinary neonicotinoids concentrations, we collected spot urine samples from15 CKD patients, 15 family members, and 62 neighbors in 2015, analyzed two renal tubular biomarkers, Cystatin-C and L-FABP, quantified seven neonicotinoids and a metabolite N-desmethyl-acetamiprid by LC–MS/MS; and we investigated their symptoms using a questionnaire. Cystatin-C and L-FABP had a positive correlation (p < 0.001). N-Desmethyl-acetamiprid was detected in 92.4% of the urine samples, followed by dinotefuran (17.4%), thiamethoxam (17.4%), clothianidin (9.8%), thiacloprid and imidacloprid. Dinotefuran and thiacloprid have never been registered in Sri Lanka. In High Cystatin-C group (> 70 μg/gCre, n = 7), higher urinary concentration of dinotefuran (p = 0.009), and in Zero Cystatin-C group (< LOQ, n = 7), higher N-desmethyl-acetamiprid (p = 0.013), dinotefuran (p = 0.049), and thiacloprid (p = 0.035), and more complaints of chest pains, stomachache, skin eruption and diarrhea (p < 0.05) were found than in Normal Cystatin-C group (n = 78). Urinary neonicotinoids may be one of the potential risk factors for renal tubular dysfunction in this area.

Variability in urinary biomarkers of human exposure to polycyclic aromatic hydrocarbons and its association with oxidative stress

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants. Urinary concentrations of mono-hydroxylated metabolites of PAHs (OH-PAHs) have been used as biomarkers of these chemicals' exposure in humans. Little is known, however, with regard to intra- and inter-individual variability in OH-PAH concentrations and their association with oxidative stress. We conducted a longitudinal study of measurement of urinary concentrations of 15 OH-PAHs and 7 oxidative stress biomarkers (OSBs) of DNA damage [8-hydroxy-2'-deoxyguanosine (8-OHdG)], lipid [malondialdehyde (MDA) and F₂-isoprostanes (PGF_2α)] and protein [o,o'-dityrosine (diY)] peroxidation in 19 individuals for 44 consecutive days. Metabolites of naphthalene (OHNap), fluorene (OHFlu), phenanthrene (OHPhe), and pyrene (OHPyr) were found in >70% of 515 urine samples analyzed, at sum concentrations (∑OH-PAH) measured in the range of 0.46-60 ng/mL. After adjusting for creatinine, OHNap and ∑OH-PAH concentrations exhibited moderate predictability, with intra-class correlation coefficients (ICCs) ranging from 0.359 to 0.760. However, ICC values were low (0.001-0.494) for OHFlu, OHPhe, and OHPyr, which suggested poor predictability for these PAH metabolites. Linear mixed-effects analysis revealed that an unit increase in ∑OH-PAH concentration corresponded to 4.5%, 5.3%, 20%, and 21% increase in respective urinary 8-OHdG, MDA, PGF_2α, and diY concentrations, suggesting an association with oxidative damage to DNA, lipids, and proteins. The daily intakes of PAHs, calculated from urinary concentrations of OH-PAHs, were 10- to 100-fold below the current reference doses. This study provides valuable information to design sampling strategies in biomonitoring studies and in assigning exposure classifications of PAHs in epidemiologic studies.

Association between Haematological Parameters and Exposure to a Mixture of Organophosphate and Neonicotinoid Insecticides among Male Farmworkers in Northern Thailand

Exposure to insecticides may result in various health problems. This study investigated the association between haematological parameters and exposure to a mixture of organophosphate (OP) and neonicotinoid (NEO) insecticides among male farmworkers in Fang district, Chiang Mai province, northern Thailand. Concentrations of urinary dialkylphosphates, non-specific metabolites of OPs, and NEOs and their metabolites and haematological parameters were measured in 143 male farmworkers. The Bayesian kernel machine regression model was employed to evaluate the associations. Exposure to a mixture of insecticides was significantly associated with the mean corpuscular haemoglobin concentration (MCHC) when the concentrations of all the compounds and their metabolites were at the 60th percentile or higher compared with the 50th percentile. Furthermore, exposure to clothianidin (CLO) showed a decreasing association with MCHC when all the other insecticides were at their mean concentrations. CLO was the most likely compound to reduce MCHC, and this was confirmed by sensitivity analysis. These findings suggest that exposure to NEO insecticides, especially CLO, affects the haematological status relating to haemoglobin parameters.

An integrated approach, based on mass spectrometry, for the assessment of imidacloprid metabolism and penetration into mouse brain and fetus after oral treatment

Imidacloprid is an insecticide belonging to neonicotinoids, a class of agonists of the nicotinic acetylcholine receptors that shows higher affinities in insects compared to mammals. However, recent evidence show that neonicotinoids can bind to the mammalian receptors, leading to detrimental responses in cultured neurons. We developed an analytical strategy which uses mass spectrometry with multiple reaction monitoring (targeted approach) and high-resolution acquisitions (untargeted approach), which were applied to quantify imidacloprid and to identify its metabolites in biological tissues after oral treatments of mice. Mouse dams were treated with doses from 0.118 mg/kg bw day up to 41 mg/kg day between gestational days 6-9. Results showed quantifiable levels of imidacloprid in plasma (from 30.48 to 5705 ng/mL) and brain (from 20.48 to 5852 ng/g) of treated mice, proving the passage through the mammalian blood-brain barrier with a high correspondence between doses and measured concentrations. Untargeted analyses allowed the identification of eight metabolites including imidacloprid-olefin, hydroxy-imidacloprid dihydroxy-imidacloprid, imidacloprid-nitrosimine, desnitro-imidacloprid, 6-chloronicotinic acid, 5-(methylsulfanyl)pyridine-2-carboxylic acid and N-imidazolidin-2-ylidenenitramide in plasma and brain. Moreover, analysis of embryonic tissues after oral treatment of mouse dams showed detectable levels of imidacloprid (816.6 ng/g after a dose of 4.1 mg/Kg bw day and 5646 ng/g after a dose of 41 mg/Kg bw day) and its metabolites, proving the permeability of the placenta barrier. Although many studies have been reported on the neurotoxicity of neonicotinoids, our study paves the way for a risk assessment in neurodevelopmental toxicity, demostrating the capability of imidacloprid and its metabolites to pass the biological barriers.

Simultaneous quantification of imidacloprid and its metabolites in tissues of mice upon chronic low-dose administration of imidacloprid

This study aimed to (i) develop a sensitive method for simultaneous detection and quantification of imidacloprid (IMI) and seven of its metabolites in tissue specimens, and to (ii) determine the biodistribution of the IMI compounds in tissues of C57BL/6J male mice; after exposure to 0.6 mg/kg bw/day of IMI (10% of no observable adverse effect level of IMI) through a powdered diet for 24 weeks. We successfully developed a method which was accurate (recoveries were ≥ 70% for most compounds), sensitive (LODs ≤ 0.47 ng/mL and LOQs ≤ 1.43 ng/mL were recorded for all detected compounds, R2 ≥ 0.99) and precise (RSDs ≤ 20%) for routine analysis of IMI and seven of its metabolites in blood and various tissue matrices. After bio-distributional analysis, IMI and five of its metabolites were detected in mice. Brain, testis, lung, kidney, inguinal white adipose tissue and gonadal white adipose tissue mainly accumulated IMI, blood and mesenteric white adipose tissue mainly accumulated IMI-olefin; liver mainly accumulated desnitro-IMI; pancreas predominately accumulated 4-hydroxy-IMI. The desnitro-dehydro-IMI and the desnitro-IMI metabolites recorded tissue-blood concentration ratios ≥ 1.0 for testis, brain, lung and kidney. The cumulative levels of the six detected IMI compounds (Σ6 IMI compounds) were found in the decreasing order: blood > testis > brain > kidney > lung > iWAT > gWAT > mWAT > liver > pancreas. Altogether, this study provided essential data needed for effective mechanistic elucidation of compound-specific adverse outcomes associated with chronic exposures to IMI in mammalian species.

Human Exposures to Neonicotinoids in Kumasi, Ghana

Neonicotinoid insecticides (NNIs) are now popular in many agricultural systems across Africa; however, the extent of human exposures to NNIs in African countries is scarcely reported. The present study evaluates neonicotinoid exposures in the consumer population of Kumasi, a cosmopolitan city in Ghana. A total of 75 human urine samples were collected from healthy volunteers (nonfarmers, aged 13-80 yr) and analyzed with a liquid chromatography electrospray ionization tandem mass spectrometry system. Seven NNIs and 3 NNI metabolites were detected in the following pattern (frequency, median concentration, maximum concentration): N-dm-acetamiprid (94.7%, 0.41 µg/L, 8.79 µg/L) > imidacloprid (70.7%, 0.15 µg/L, 211.62 µg/L) > N-(6-chloro-3-pyridylmethyl)-N-ethyl-N'-methylformamidine (62.2%, 0.43 µg/L, 53.85 µg/L) > 2-[N-(6-chloro-3-pyridylmethyl)-N-ethylamino]-2-(methylimino)acetic acid (56.8%, 0.10 µg/L, 3.53 µg/L) > clothianidin (40%, >limit of quantification [LOQ], 0.45 µg/L) > nitenpyram (18.7%, >LOQ, 0.14 µg/L) ≈ thiamethoxam (18.7%, >LOQ, 0.21 µg/L) > dinotefuran (12.0%, >LOQ, 1.01 µg/L) > acetamiprid (2.7%, >LOQ, 0.08 µg/L) ≈ thiacloprid (2.7%, >LOQ, 0.14 µg/L). Approximately 92% of the subjects were found to be exposed to multiple neonicotinoids simultaneously. The mean, median, and maximum imidacloprid equivalent of the relative potency factor of NNIs were found to be 1.6, 0.5, and 22.52, respectively. The median estimated daily intakes of acetamiprid, imidacloprid, and nitenpyram were 0.47, 1.27, and 0.02 µg/kg/d for females and 0.91, 0.66, and 0.08 µg/kg/d for males, respectively. The maximum daily intakes of all the NNIs were <1% of their chronic reference doses (cRfDs), except for imidacloprid and thiacloprid which recorded maximum daily intakes corresponding to 17.97 and 8.28% of cRfDs, respectively. To the best of our knowledge, the present study is the first biomonitoring report on neonicotinoid insecticides in Africa. Environ Toxicol Chem 2021;40:2306-2318. © 2021 SETAC.

Occurrence and distribution of neonicotinoids and characteristic metabolites in paired urine and indoor dust from young adults: Implications for human exposure

Neonicotinoid insecticides (NEOs) are widely used for pest control worldwide. The profile of NEOs in paired urine and indoor dust has not yet been reported in China. In this study, 40 paired samples (i.e., 160 urine and 40 indoor dust) were collected from university students and dormitories from Guangzhou City of China to measure the concentrations of six NEOs and their three metabolites. Target analytes were frequently detected in paired urine (81%-98%) and indoor dust (75%-95%) samples, with median concentrations ranging from 0.02 [specific gravity (SG) adjusted: 0.02] to 2.08 (SG-adjusted: 2.38) ng/mL in urine and from 0.05 to 2.74 ng/g in indoor dust. 5-Hydroxy-imidacloprid was predominant in urine, while N-desmethyl acetamiprid was predominant in indoor dust samples, accounting for 56% and 37%, respectively. 1-Methyl-3-(tetrahydro-3-furylmethyl) urea, a dinotefuran degradate, was measured for the first time in indoor dust, with the median level of 1.02 ng/g. Significant gender-related differences (p < 0.05) in the urinary concentrations of most NEOs were found. We calculated the estimated daily intake (EDI) of target compounds from urine and indoor measurements. The EDIs of target analytes varied among all urine and indoor dust samples, with median values ranging from 0.51 (SG-adjusted: 0.56) to 51.6 (SG-adjusted: 52.8) ng/kg bw/day and from 0.04 to 2.10 pg/kg bw/day, respectively. Moreover, the median EDIs_urine of most target analytes in females were significantly higher than (p < 0.05) those in males. The median EDIs_dust of target compounds in dust from female dormitories were slightly higher than that in dust from male dormitories. These findings indicated that females were more exposed to NEO than males. Thus, the potential health risks of exposure to NEOs and their metabolites in female adults should be addressed in future studies. To our knowledge, this study is the first to report the profiles of NEOs and their metabolites in paired urine and indoor dust samples from young adults in China.

Profiles of neonicotinoid insecticides and characteristic metabolites in paired urine and blood samples: Partitioning between urine and blood and implications for human exposure

Neonicotinoid insecticides (NEOs) are widely used for pest control worldwide. However, only a few studies have analyzed NEOs and their metabolites in blood samples, and no study has measured the concentrations of NEOs and their metabolites in paired urine and blood samples. In this study, six NEOs and three characteristic metabolites were detected in 196 paired urine and blood samples collected from young adults from China. The NEOs and their metabolites were widely detected in paired urine (67%-91%) and blood (64%-97%) samples, and the median levels ranged within 0.01-1.15 ng/mL in urine and 0.08-0.80 ng/mL in blood. Olefin-imidacloprid (Of-IMI) and 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF) were the most abundant target compounds in the urine (32.4%) and blood (26.4%) samples, respectively. Gender-related differences were observed in the concentrations of most NEOs and their metabolites in the urine and blood samples. The partitioning of target analytes between blood and urine (NEOs-B/NEOs-U ratios) was also calculated in this study. The B/U ratios of most NEOs and their metabolites were below 1, and positive correlations were observed between urine and blood in most levels of NEOs and their metabolites. This finding indicates that urinary levels are good predictors of human exposure to NEOs and their metabolites. The estimated daily intake (EDI) and the imidacloprid-equivalent (IMI_eq) levels of NEOs and their metabolites in 196 young adults were also determined. The median EDI values (ng/kg bw/day) of ΣNEOs (sum of NEOs and their metabolites) and IMI_eq in females (194.9 and 458.2) were slightly higher than (p > 0.05) those in males (157.1 and 439.7). This finding shows young adults are extensively exposed to NEOs and their metabolites. To our knowledge, this study is the first to report about NEOs and their metabolites in paired samples of urine and blood in China.

Exposure to Organophosphate and Neonicotinoid Insecticides and Its Association with Steroid Hormones among Male Reproductive-Age Farmworkers in Northern Thailand

Several studies indicated organophosphate (OP) and neonicotinoid (NEO) insecticides are endocrine disruptors; however, data are scarce. This cross-sectional study recruited 143 male farmworkers aged 18-40 years in Fang district, Chiang Mai province, northern Thailand. OP exposure was assessed by measuring urinary dialkylphosphate (DAPs) using a gas-chromatography flame photometric detector. Urinary NEOs, their metabolites (NEO/m) and serum steroid hormones were measured using liquid chromatography-tandem mass spectrometry. Characteristics of participants were determined by face-to-face interviews. DAPs and five NEO/m were detected in more than 60% of samples. The concentration of diethylphosphate was highest among DAP metabolites (geometric mean concentration (GM: 23.9 ng/mL) and the concentration of imidacloprid (IMI) was highest among NEO/m (GM: 17.4 ng/mL). Linear regression models showed that the IMI level was positively associated with testosterone, dehydrocorticosterone (DHC) and dehydroepiandrosterone (DHEA) levels. Imidacloprid-olefin and DHEA levels were positively associated. Thiamethoxam (THX) were inversely associated with DHC and deoxycorticosterone levels. Clothianidin (CLO), THX and N-desmethyl-acetamiprid levels were positively associated with the androstenedione level. CLO and THX levels were inversely associated with the cortisone level. In conclusion, the association between NEO insecticides exposure and adrenal androgens, glucocorticoids and mineralocorticoids, suggest potential steroidogenesis activities. Our findings warrant further investigation.

Oxidative stress and decreased dopamine levels induced by imidacloprid exposure cause behavioral changes in a neurodevelopmental disorder model in Drosophila melanogaster

Neurodevelopmental disorders, such as Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) are responsible for behavioral deficits in children. Imidacloprid is a nicotinic acetylcholine receptor agonist, capable of causing behavioral changes in Drosophila melanogaster, similar to the ADHD-like phenotypes. We assess whether behavioral damage induced by imidacloprid exposure in Drosophila melanogaster is associated with neurochemical changes and whether these changes are similar to those observed in neurodevelopmental disorders such as ASD and ADHD. The fruit flies were divided into four groups, exposed to either a standard diet (control) or a diet containing imidacloprid (200, 400 or 600 ρM) and allowed to mate for 7 days. After hatching, the progeny was subjected to in vivo and ex vivo tests. The ones exposed to imidacloprid showed an increase in hyperactivity, aggressiveness, anxiety and repetitive movements, as well as, a decrease in social interaction. Furthermore, exposure to imidacloprid decreased dopamine levels, cell viability and increased oxidative stress in the flies' progeny. These results demonstrated that the behavioral damage induced by imidacloprid exposure involves a reduction in dopamine levels and oxidative stress and that these neurochemical changes are in line with the events that occur in ASD and ADHD-like phenotypes in other models.