Changes in pest infestation levels, self-reported pesticide use, and permethrin exposure during pregnancy after the 2000-2001 U.S. Environmental Protection Agency restriction of organophosphates

Field agrochemical exposure impacts locomotor activity in wild bumblebees

Agricultural intensification has been identified as one of the key causes of global insect biodiversity losses. These losses have been further linked to the widespread use of agrochemicals associated with modern agricultural practices. Many of these chemicals are known to have negative sublethal effects on commercial pollinators, such as managed honeybees and bumblebees, but less is known about the impacts on wild bees. Laboratory-based studies with commercial pollinators have consistently shown that pesticide exposure can impact bee behavior, with cascading effects on foraging performance, reproductive success, and pollination services. However, these studies typically assess only one chemical, neglecting the complexity of real-world exposure to multiple agrochemicals and other stressors. In the summer of 2020, we collected wild-foraging workers of the common eastern bumblebee, Bombus impatiens, from five squash (Cucurbita) agricultural sites (organic and conventional farms), selected to represent a range of agrochemical, including neonicotinoid insecticide, use. For each bee, we measured two behaviors relevant to foraging success and previously shown to be impacted by pesticide exposure: sucrose responsiveness and locomotor activity. Following behavioral testing, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) chemical analysis to detect and quantify the presence of 92 agrochemicals in each bumblebee. Bees collected from our sites did not vary in pesticide exposure as expected. While we found a limited occurrence of neonicotinoids, two fungicides (azoxystrobin and difenoconazole) were detected at all sites, and the pesticide synergist piperonyl butoxide (PBO) was present in all 123 bees. We found that bumblebees that contained higher levels of PBO were less active, and this effect was stronger for larger bumblebee workers. While PBO is unlikely to be the direct cause of the reduction in bee activity, it could be an indicator of exposure to pyrethroids and/or other insecticides that we were unable to directly quantify, but which PBO is frequently tank-mixed with during pesticide applications on crops. We did not find a relationship between agrochemical exposure and bumblebee sucrose responsiveness. To our knowledge, this is the first evidence of a sublethal behavioral impact of agrochemical exposure on wild-foraging bees.

Associations of pyrethroid exposure with skeletal muscle strength and mass

This study aimed to examine the associations of pyrethroid exposure with handgrip strength and skeletal muscle mass and potential modification effects in US adults. The data from the National Health and Nutrition Examination Survey was used. Handgrip strength was determined with a handgrip dynamometer, and we quantified muscle mass by using the appendicular skeletal muscle index (ASMI). Urinary 3-Phenoxybenzoic Acid (3-PBA), a validated biomarker for pyrethroid exposure, was used in the primary analysis. After adjusting for other covariates, participants exposed to the highest tertile of 3-PBA exposure had significantly lower handgrip strength (β = -1.88, 95% CI: -3.29, -0.23, P = 0.026) than those exposed to the lowest tertile of 3-PBA. Similarly, the 3-PBA exposure was marginally significantly associated with ASMI (Tertile 3 vs. Tertile 1: β = -0.07, 95% CI: -0.14, -0.01, P = 0.056). Significant interactions were found between 3-PBA and body mass index (BMI) on handgrip strength and ASMI (P interaction < 0.05), which indicated a potential moderation effect of BMI on the associations. In conclusion, pyrethroid exposure was adversely associated with handgrip strength and skeletal muscle mass, especially in overweight and obese populations. Further studies are warranted to confirm our results and to explore the potential mechanisms.

Maternal and Paternal Household Pesticide Exposure During Pregnancy and Risk of Childhood Acute Lymphoblastic Leukemia

OBJECTIVE

The aim of this study was to investigate whether risk estimates for childhood acute lymphoblastic leukemia change when restricting model comparison groups to "nonpesticide exposure" (NPE10) households.

METHODS

Cases ( n = 1810) 15 years or younger were identified through Children's Cancer Group institutions between 1989 and 1993 and age-/sex-matched to controls ( n = 1951). Household pesticide use during pregnancy/month prior was collected via telephone. NPE10 comparison group reporting no parental exposure to 10 pesticide classes was identified.

RESULTS

Adjusted odds ratios increased from 15% to 49% when limiting the comparison to NPE10. Maternal termite insecticide exposure was associated with greatest risk (adjusted odds ratio, 4.21; 95% confidence interval, 2.00-8.88). There was minimal evidence of interaction by child sex or occupational pesticide exposure, and no monotonic dose-response pattern with frequency of use (times per year).

CONCLUSIONS

Elevated risks are consistent with published pooled-/meta-analyses and DNA damage. The consistency and magnitude of these associations warrant product labeling, exposure reduction interventions, or both.

Co-exposure of organophosphorus pesticides is associated with increased risk of type 2 diabetes mellitus in a Chinese population

OBJECTIVE

The epidemiological evidence of human exposure to organophosphorus pesticides (OPPs) with type 2 diabetes mellitus (T2DM) and prediabetes (PDM) is scarce. We aimed to examine the association of T2DM/PDM risk with single OPP exposure and multi-OPP co-exposure.

METHODS

Plasma levels of ten OPPs were measured using the gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) among 2734 subjects from the Henan Rural Cohort Study. We used generalized linear regression to estimate odds ratios (ORs) or β with 95% confidence intervals (CIs), and constructed quantile g-computation and Bayesian kernel machine regression (BKMR) models to investigate the association of OPPs mixture with the risk of T2DM and PDM.

RESULTS

High detection rates ranged from 76.35% (isazophos) to 99.17% (malathion and methidathion) for all OPPs. Several plasma OPPs concentrations were in positive correlation with T2DM and PDM. Additionally, positive associations of several OPPs with fasting plasma glucose (FPG) values and glycosylated hemoglobin (HbA1c) levels were observed. In the quantile g-computation, we identified significantly positive associations between OPPs mixtures and T2DM as well as PDM, and fenthion had the greatest contribution for T2DM, followed by fenitrothion and cadusafos. As for PDM, the increased risk was largely explained by cadusafos, fenthion, and malathion. Furthermore, BKMR models suggested that co-exposure to OPPs was linked to an increased risk of T2DM and PDM.

CONCLUSION

Our findings suggested that the individual and mixture of OPPs co-exposure were associated with an increased risk of T2DM and PDM, implying that OPPs might act an important role in the development of T2DM.

The quest for metabolic biomarkers of agrochemicals exposure via in vitro studies and suspect screening

Numerous agrochemicals, including pesticides and herbicides, are applied in modern agriculture, resulting in concerns for the ecosystem and human safety as humans are easily exposed to these compounds. Many agrochemicals, and their transformation products or metabolites, have shown toxicity in in vitro and in vivo studies. However, given the rapid development of novel agrochemicals, for many there is no information about their effects nor about metabolic transformations when ingested by humans. Tracing biomarkers may be the best method for assessing the impacts of agrochemicals. A combination of in vitro metabolism study and suspect screening of human samples (e.g., urine, blood) can be utilized to efficiently find biomarkers for agrochemical exposure. In the work reported here, we determined the in vitro metabolic profiling of six prioritized pesticides and synergists, namely boscalid, carbendazim, piperonyl butoxide, spiroxamine, dimethomorph and fludioxonil, in human liver microsomes. 17 major metabolites were structurally elucidated by high resolution mass spectrometry (HRMS). Major metabolic transformation processes (e.g., hydroxylation, demethylation and oxidation) were proposed for each pesticide. Individual in silico toxicity assessments showed that some metabolites had the same or even enhanced toxicity compared to parent compounds. Information about these metabolites obtained from HRMS was used for suspect screening in human activities related samples. Carbendazim and a metabolite of fludioxonil were identified in wastewater and laboratory urine samples, respectively. Our findings provide concrete evidence for the use of in vitro metabolites as biomarkers in biomonitoring studies of potential exposure to toxic chemicals.

Association between serum pyrethroid insecticide levels and incident type 2 diabetes risk: a nested case-control study in Dongfeng-Tongji cohort

Pyrethroid insecticides have been extensively used worldwide, but few studies explored the prospective association between pyrethroid exposure and incident type 2 diabetes (T2D). We conducted a nested case-control study of 2012 paired cases and controls, and measured eight pyrethroid insecticides in the baseline sera. We used conditional logistic regression models to estimate odds ratios (ORs) with 95% confidence intervals, and constructed multiple-pollutant models to investigate the association of pyrethroid mixture with incident T2D risk. The median concentrations (detection rates) were 3.53 μg/L (92.45%), 0.52 μg/L (99.80%), 1.16 μg/L (90.61%) and 1.43 μg/L (99.95%) for permethrin, cypermethrin, fenvalerate, and deltamethrin, respectively. Compared to participants with serum fenvalerate levels in the first quartile, the multivariable-adjusted ORs of incident T2D were 1.20 (95% CI 0.86-1.67), 1.41 (0.97-2.05), and 2.29 (1.27-4.11) for the second, third and fourth quartile (P trend = 0.01). Spline analysis further confirmed the positive association between serum fenvalerate levels and incident T2D risk (P for overall association = 0.006). Furthermore, mixture models revealed a positive association of pyrethroid mixture with incident T2D risk, with serum fenvalerate ranked as the top contributor (proportion of relative contribution: > 70%). We found that high concentrations of serum pyrethroid insecticides were significantly associated with an increased risk of incident T2D. The elevated risk was largely explained by fenvalerate. Further investigations are urgently needed to confirm our findings and elucidate the underlying mechanisms, given the widespread use of pyrethroids and the global pandemic of diabetes.

Maternal and fetal tissue distribution of α-cypermethrin and permethrin in pregnant CD-1 mice

Pyrethroid insecticides are widely used throughout agriculture and household products. Recent studies suggest that prenatal exposure to these insecticides may adversely affect fetal development; however, little is known about the distribution of these chemicals in pregnant animals. The present study aimed to address this gap in knowledge by investigating the distribution of two commonly used pyrethroid insecticides, permethrin and α-cypermethrin, in maternal and fetal tissues of pregnant CD-1 mice. Dams were dosed from gestational days 6 to 16 via oral gavage with permethrin (1.5, 15, and 50 mg/kg), α-cypermethrin (0.3, 3, and 10 mg/kg), or corn oil vehicle. Pyrethroid levels were determined in gestational day 16 tissues collected 90 min after the final dose was administered. Across maternal tissues, levels of both pyrethroids were the highest in maternal ovaries, followed by liver and brain, respectively. In addition, levels of both pyrethroids in maternal tissues and placenta were significantly higher than those in the fetal body and amniotic fluid, suggesting that these compounds may exhibit low transfer across the mouse placenta. While additional toxicokinetic studies are needed to verify the time course of pyrethroids in the fetal compartment, these findings support investigation into indirect modes of action relevant to the effects of pyrethroids on mammalian fetal development.

Does Insect Aversion Lead to Increased Household Pesticide Use?

In many human societies, domestic insect pests often evoke feelings of disgust, fear and aversion. These common feelings may translate to increased use of household pesticides. No study has ever explored this possibility and consequently, efforts to mitigate public exposure to domestic pesticides typically focus on addressing knowledge gaps. We tested the hypothesis that negative emotions toward insects may motivate people to use pesticides, by interviewing 70 participants and assessing their insect aversion levels using a computerized test. Contrary to our hypothesis, we found no effect of insect aversion on pesticide use. However, we did find that personal attributes and preferences such as wishing to avoid exposure to toxic chemicals, being vegetarian and taking frequent nature walks reduced pesticide use, in addition to low infestation levels and physical attributes of the housing unit. We emphasize the importance of conducting future studies in various societies, where insect aversion and other factors may have different effects on household pesticide use. Such studies may provide culture-specific insights that could foster the development of next-generation urban IPM (Integrated Pest Management) public education programs, which will address not only knowledge gaps, but also emotional aspects and personal attributes that lead to unnecessary or excessive use of household pesticides.

Prevalence of Cockroaches, Bed Bugs, and House Mice in Low-Income Housing and Evaluation of Baits for Monitoring House Mouse Infestations

Pests are frequently found in homes, especially in apartment buildings in low-income communities. We investigated the prevalence and patterns of pest infestations in low-income communities in four cities (Jersey City, Linden, Paterson, Trenton) in New Jersey, USA. Resident interviews, visual inspections, and the placement of monitors were used to identify pest infestations. A total of 1,753 apartments from 19 buildings or building complexes were accessed. The infestation rates of cockroaches, bed bugs (Cimex lectularius L.), and house mice (Mus musculus domesticus Schwarz and Schwarz) were 37, 9, and 20%, respectively. Among apartments with cockroaches, 97.8, 2.5, and 0.8% had German cockroach [Blattella germanica (L.)], American cockroach [Periplaneta americana (L.)], and Oriental cockroach (Blatta orientalis L.), respectively. The percentage of residents who were aware of the presence of cockroaches, bed bugs, and house mice was 70.8, 55.3, and 56.8%, respectively. The prevalence of pest infestation was associated with resident ethnicity and gender. Among 856 interview responses, 78% implemented methods themselves to control pests in their homes in the past six months. Chocolate spread detected 99% of house mouse infestations and was much more sensitive than three commercial blank baits. Significant differences were also observed in the feeding preference of the three commercial blank baits.

Effects of prenatal exposure to pyrethroid pesticides on neurodevelopment of 1-year- old children: A birth cohort study in China

Pregnant women have been ubiquitously exposed to pyrethroid pesticides. Previous studies, mainly based on third trimester measurements of maternal urinary pyrethroid metabolites, have reported inconsistent findings in the effects of prenatal pyrethroid exposure on children's neurodevelopmental outcomes. The purpose of this study was to clarify if pyrethroid exposure during the entire three trimesters of pregnancy may be associated with deleterious effects on infant neurodevelopmental status, particularly at a high dosage of exposure. We measured maternal urinary concentrations of pyrethroid metabolites in all trimesters of pregnancy and assessed children's neurodevelopment at one year of age using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). Multiple linear regression models were used to estimate the effects of metabolites (3-PBA, 4 F-3-PBA, cis-DBCA) in each trimester on BSID-III composite scores. Logistic regression analyses were applied to predict developmental delay vs non-delayed status (cut-off composite score of below 80 for developmental delay) based on the maternal levels of pyrethroid metabolites. In the first, second and third trimesters of pregnancy, the detection rates of pyrethroid metabolites were 94.7%, 90.7%, and 89.0%; the 50th percentiles of exposure level were 0.24 μg/g, 0.24 μg/g and 0.21 μg/g for 3-PBA, 0.14 μg/g, 0.17 μg/g and 0.15 μg/g for 4 F-3PBA, 0.21 μg/g, 0.25 μg/g and 0.19 μg/g for cis-DBCA respectively. In the second trimester, 3-PBA was inversely associated with Cognition and Language scores [β = -3.34 (95% CI = -6.11, -0.57) and β = -2.90 (95% CI = -5.20, -0.61), respectively], and significantly increased the risk of Cognition and Language developmental delay [OR= 1.64 (95% CI = 1.03, 2.62) and OR = 1.52 (95% CI = 1.06, 2.19), respectively]; cis-DBCA was inversely associated with Adaptive Behavior scores [β = -0.73 (95% CI = -1.27, -0.19)], and significantly increased the risk of Adaptive Behavior developmental delay [OR= 1.11 (95% CI = 1.02, 1.21)]. When the maternal levels of pyrethroid metabolites were stratified into the regression models according to the 90th percentile of exposure, in the first trimester, Cognition and Motor scores were inversely associated with higher cis-DBCA [β = -7.19 (95% CI = -12.97, -1.41) and β = -8.20 (95% CI = -13.35, -3.05), respectively], Language scores were inversely associated with higher 3-PBA [β = -6.01 (95% CI = -10.96, -1.06)]; in the second trimester, Cognition scores were inversely associated with higher cis-DBCA [β = -6.64 (95% CI = -12.51, -0.76)], Language scores were inversely associated with higher 3-PBA [β = -5.17 (95% CI = -10.07, -0.27)] and cis-DBCA [β = -5.40 (95% CI = -10.28, -0.52)]. We concluded that pyrethroid exposure in the first and second trimesters was associated with poorer infants neurodevelopmental outcomes at one year of age, and these effects were particularly pronounced at high levels of pyrethroid exposure.

The association of prenatal and childhood pyrethroid pesticide exposure with school-age ADHD traits

BACKGROUND

Pyrethroid insecticides are commonly used in residential settings, and their use has increased rapidly. Although research has been scarce, they have been reported to be associated with impaired neurodevelopment. Moreover, susceptible exposure windows and the long-term effects of pyrethroids have not been investigated. We examined the association between pyrethroid exposure and attention-deficit/hyperactivity disorder (ADHD) symptoms over time, with exposure windows spanning from the prenatal period to school-age.

METHODS

Using 524 mother-child pairs, we measured urinary concentrations of 3-phenoxybenzoic acid (3-PBA), a major pyrethroid metabolite, and asked parents to fill-out the ADHD Rating Scale IV (ARS). We used Poisson regression to identify the susceptible periods of pyrethroid exposure, by correlating various 3-PBA exposure windows (prenatal, ages 2, 4, 6 and 8) with ADHD symptoms at ages 6 and 8.

RESULTS

Doubling of prenatal and age 2 3-PBA concentrations was associated with increased ADHD symptoms at age 6 (2.7% change, 95% confidence interval [CI]: 0.3, 5.2; 5.2% change [95% CI: 0.5, 10.2], respectively). The 3-PBA concentrations at age 4 and age 6 were linked with ADHD symptoms at age 8 (2.7% change [95% CI: 0.3, 5.3]; 3.3% change [95% CI: 0.2, 6.4], respectively). There were no clear sex-specific patterns in association.

DISCUSSION

Both prenatal and early-childhood exposure to 3-PBA were found to be associated with ADHD symptoms. Exposure during pregnancy, and at ages 2 to 6 were found to be susceptible periods for pyrethroid neurotoxicity at ages 6 and 8.

Household pesticide exposures and infant gross motor development in the MADRES cohort

BACKGROUND

The development of motor skills in infancy is a vital neurodevelopmental milestone. Although previous studies have explored the neurotoxic effects of agricultural pesticides on infants' motor development, limited research has examined early postnatal household pesticide use on infants' motor development, particularly among urban communities.

OBJECTIVE

This study examined the association between early postnatal household pesticide use and infants' gross and fine motor development at 6 months of age.

METHODS

Questionnaires were administered via telephone to 296 mother-infant dyads in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) pregnancy cohort. Early life household pesticide use was assessed via questionnaire administered when infants turned 3 months old and gross and fine motor development was assessed by the Ages and Stages Questionnaire (ASQ-3) at 6 months old. Infant gross motor scores were reverse coded so that higher scores indicated lower gross motor performance. Negative binomial regressions were performed to assess the relationship between household pesticide use and infant gross motor development.

RESULTS

Infants were predominantly Hispanic (78.7%) and full term (gestational age at birth: 39.0 ± 1.9 weeks), with 22.3% of maternal participants reporting household use of rodent and insect pesticides. Adjusting for recruitment site, maternal age, ethnicity, household income, education, infant corrected age, infant sex, and home type, infants with maternal-reported household use of rodent and insect pesticides had 1.30 times higher expected gross motor scores (95% confiidence interval 1.05, 1.61) than infants with no reported use of household pesticides, with higher scores indicating reduced gross motor performance.

CONCLUSIONS

Our results suggest household use of rodent and insect pesticides may harm infants' gross motor development in early childhood. Future research should evaluate the impact of specific household chemicals in infant biospecimens and their associations with infant motor development to confirm these findings.

Parenting, Pesticides and Adolescent Psychological Adjustment: A Brief Report

Pesticides used to control insects, such as pyrethroids, are neurotoxicants, yet adolescent researchers often overlook their potential role in adolescent psychological adjustment. This brief report is guided by bioecological theory and considers the possible independent and interactive effects of environmental pyrethroid pesticide exposure for adolescent depressive symptoms. Self-reported adolescent appraisals of the parent-child relationship and depressive symptoms were obtained from a convenience sample of impoverished, predominantly Latino urban youth (n = 44). Exposure to environmental pyrethroids was obtained from wipe samples using a standardized protocol. Parent-adolescent conflict was higher in households with bifenthrin than those without, and adolescent depressive symptoms were elevated in homes where cypermethrin was detected. In addition, the presence of bifenthrin in the home attenuated the protective effects of parental involvement on adolescent depressive symptoms. The current results suggest that adolescent mental health researchers must consider the synergistic combinations of adolescents' environments' physical and social features. Given the endemic presence of pesticides and their neurotoxic function, pesticide exposure may demand specific attention.

Exposure to Sub-Lethal Doses of Permethrin Is Associated with Neurotoxicity: Changes in Bioenergetics, Redox Markers, Neuroinflammation and Morphology

Permethrin (PERM) is a member of the class I family of synthetic pyrethroids. Human use has shown that it affects different systems, with wide health dysfunctions. Our aim was to determine bioenergetics, neuroinflammation and morphology changes, as redox markers after subacute exposure to PERM in rats. We used MDA determination, protein carbonyl assay, mitochondrial O₂ consumption, expression of pro-inflammatory cytokines and a deep histopathological analysis of the hippocampus. PERM (150 mg/kg and 300 mg/kg body weight/day, o.v.) increased lipoperoxidation and carbonylated proteins in a dose-dependent manner in the brain regions. The activities of antioxidant enzymes glutathione peroxidase, reductase, S-transferase, catalase, and superoxide dismutase showed an increase in all the different brain areas, with dose-dependent effects in the cerebellum. Cytokine profiles (IL-1β, IL-6 and TNF-α) increased in a dose-dependent manner in different brain tissues. Exposure to 150 mg/kg of permethrin induced degenerated and/or dead neurons in the rat hippocampus and induced mitochondrial uncoupling and reduction of oxidative phosphorylation and significantly decreased the respiratory parameters state 3-associated respiration in complex I and II. PERM exposure at low doses induces reactive oxygen species production and imbalance in the enzymatic antioxidant system, increases gene expression of pro-inflammatory interleukins, and could lead to cell damage mediated by mitochondrial functional impairment.

Combined Maternal Exposure to Cypermethrin and Stress Affect Embryonic Brain and Placental Outcomes in Mice

Prenatal exposure to cypermethrin is a risk factor for adverse neurodevelopmental outcomes in children. In addition, maternal psychological stress during pregnancy has significant effects on fetal neurodevelopment and may influence end-stage toxicity to offspring by altering maternal xenobiotic metabolism. As such, this study examined effects of maternal exposure to alpha-cypermethrin and stress, alone and in combination, on offspring development, with a focus on fetal neurotoxicity. CD1 mouse dams were administered 10 mg/kg alpha-cypermethrin or corn oil vehicle via oral gavage from embryonic day 11 (E11) to E14. In addition, dams from each treatment were subjected to a standard model of restraint stress from E12 to E14. Cypermethrin treatment impaired fetal growth, reduced fetal forebrain volume, and increased ventral forebrain proliferative zone volume, the latter effects driven by combined exposure with stress. Cypermethrin also impaired migration of GABAergic progenitors, with different transcriptional changes alone and in combination with stress. Stress and cypermethrin also interacted in effects on embryonic microglia morphology. In addition, levels of cypermethrin were elevated in the serum of stressed dams, which was accompanied by interacting effects of cypermethrin and stress on hepatic expression of cytochrome P450 enzymes. Levels of cypermethrin in amniotic fluid were below the limit of quantification, suggesting minimal transfer to fetal circulation. Despite this, cypermethrin increased placental malondialdehyde levels and increased placental expression of genes responsive to oxidative stress, effects significantly modified by stress exposure. These findings suggest a role for interaction between maternal exposures to cypermethrin and stress on offspring neurodevelopment, involving indirect mechanisms in the placenta and maternal liver.

Effects of pyrethroids on brain development and behavior: Deltamethrin

Deltamethrin (DLM) is a Type II pyrethroid pesticide widely used in agriculture, homes, public spaces, and medicine. Epidemiological studies report that increased pyrethroid exposure during development is associated with neurobehavioral disorders. This raises concern about the safety of these chemicals for children. Few animal studies have explored the long-term effects of developmental exposure to DLM on the brain. Here we review the CNS effects of pyrethroids, with emphasis on DLM. Current data on behavioral and cognitive effects after developmental exposure are emphasized. Although, the acute mechanisms of action of DLM are known, how these translate to long-term effects is only beginning to be understood. But existing data clearly show there are lasting effects on locomotor activity, acoustic startle, learning and memory, apoptosis, and dopamine in mice and rats after early exposure. The most consistent neurochemical findings are reductions in the dopamine transporter and the dopamine D1 receptor. The data show that DLM is developmentally neurotoxic but more research on its mechanisms of long-term effects is needed.

Analysis of six pyrethroid insecticide metabolites in cord serum using a novel gas chromatography-ion trap mass spectrometry method

Pyrethroid insecticides are commonly used for residential and commercial pest control in the US. Pregnant women and their fetuses are vulnerable to pesticide exposures during critical windows of neurodevelopment. Biomonitoring for exposure requires accurate and sensitive methods to assess exposures during pregnancy. The objective of this study was to develop a sensitive analytical method to measure pyrethroid metabolite concentrations in cord serum. Six pyrethroid metabolites, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (c/t-DCCA), trans-chrysanthemum dicarboxylic acid (t-CDCA), cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (c-DBCA), 4-fluoro-3-phenoxybenzoic acid (FPBA), and 3-phenoxybenzoic acid (3PBA) were extracted from cord serum by a dichloromethane liquid-liquid extraction, derivatized by 1,1,1,3,3,3-hexafluoro-2-propanol carboxylic acid esterification, and then measured by gas chromatography/ion trap mass spectrometry. Limits of detection ranged from 0.02 to 0.6 ng/mL. Sixty-three cord serum samples were collected from maternal-fetal dyads in central New Jersey to test for pyrethroid metabolites. Non-specific metabolites, 3PBA, t-DCCA, and t-CDCA, were detected most frequently, present in 29%, 6.3% and 6.3% of samples, respectively. Sensitivities were comparable or greater than other published studies assessing pyrethroid metabolites in cord blood. Comparisons with other literature-reported studies emphasize the importance of method sensitivity when assessing exposures at biologically relevant concentrations.

Environmental exposure to pyrethroid pesticides in a nationally representative sample of U.S. adults and children: The National Health and Nutrition Examination Survey 2007-2012

Pyrethroids are an important class of insecticides, and thousands of tons of these compounds are used in the United States every year. This study characterized exposures to pyrethroids and assessed demographic, socioeconomic, and lifestyle factors that modulate pyrethroid exposure using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012, a nationally representative survey of the non-institutionalized population of the United States. Urinary levels of commonly used biomarkers of pyrethroid exposure, including 3-phenoxybenzoic acid (3-PBA), 4-fluoro-3-phenoxybenzoic acid (F-PBA), and cis-dibromovinyl-dimethylcyclopropane carboxylic acid (DBCA), were determined by liquid chromatography-tandem mass spectrometry. The detection rate of 3-PBA, a nonspecific metabolite of several pyrethroids, was 78.1% in adults (N = 5233) and 79.3% in children (N = 2295). The detection rates of all other pyrethroid metabolites were <10%. The median urinary level of 3-PBA in adults was 0.47 μg/L (interquartile range, 0.14-1.22 μg/L). For children, the median urinary level was 0.49 μg/L (interquartile range, 0.17-1.29 μg/L). Age, gender, family income-to-poverty ratio (PIR), levels of physical activity, alcohol intake, and body mass index were associated with 3-PBA levels in adults. In children, age, gender, race/ethnicity, and PIR were associated with 3-PBA levels. 3-PBA levels also differed significantly across NHANES cycles, with higher levels observed in NHANES 2011-2012. Geometric mean 3-PBA levels in U.S. adults were 0.41 μg/L in NHANES 2007-2008, 0.41 μg/L in NHANES 2009-2010, and 0.66 μg/L in NHANES 2011-2012. In U.S. children, geometric mean 3-PBA levels were 0.40 μg/L in NHANES 2007-2008, 0.46 μg/L in NHANES 2009-2010, and 0.70 μg/L in NHANES 2011-2012. These results demonstrate that pyrethroid exposures remain a current environmental health concern and lay the foundation for further preclinical and epidemiological studies assessing human health risks associated with pyrethroids.

Residential pyrethroid insecticide use, urinary 3-phenoxybenzoic acid levels, and attention-deficit/hyperactivity disorder-like symptoms in preschool-age children: The Environment and Development of Children study

Previous animal studies have reported that pyrethroids can cause dopamine system abnormalities and attention-deficit/hyperactivity disorder (ADHD) phenotypes. However, epidemiological studies investigating the associations between pyrethroid exposure and ADHD are limited. We aimed to investigate the association between pyrethroid exposure and ADHD-like symptoms among preschool-age children. We used data from 385 children at 4 years of age participating in the Environment and Development of Children (EDC) study. We evaluated pyrethroid exposure through questionnaires and urinary 3-phenoxybenzoic acid (3-PBA) concentrations. We assessed ADHD-like symptoms using the Korean ADHD rating scale (K-ARS). We conducted negative binomial regressions to evaluate the associations between pyrethroid exposure and ADHD-like symptoms. Residential use of insecticide adhesive (β = 0.42, 95% CI: 0.11, 0.74) and insecticide spray (β = 0.33, 95% CI: 0.08, 0.59) was associated with an increase in log-transformed creatinine-adjusted urinary 3-PBA concentrations. Residential insecticide adhesive use was associated with a 51.6% increase in K-ARS scores (95% confidence interval [CI]: 6.3, 116.1) among boys, when compared with non-users. When compared with creatinine-adjusted 3-PBA levels <0.50 μg/g creatinine, creatinine-adjusted 3-PBA levels ≥3.80 μg/g creatinine were associated with a 58% increase in K-ARS scores (95% CI: 0.1, 150.5) among boys. We found associations of residential pyrethroid insecticide use and urinary 3-PBA concentrations with K-ARS scores among preschool-age boys. Since the present study explored cross-sectional associations in preschool-age children, the possibility of reverse causality cannot be dismissed. Further studies implementing a cohort study design are warranted.

The effect of non-organophosphate household pesticides exposure during pregnancy on infants birth sizes and growth rate: a cohort study

Background

To date, there is limited evidence on the effect of antenatal exposure to non-organophosphate household pesticides on infant health. Our hypothesis is that antenatal exposure to non-organophosphate household pesticides will be associated with birth sizes and infant growth rate.

Methods

In this prospective cohort study, 284 mother-infant pairs were studied. Mothers were recruited at the third trimester in two primary care centers and one private hospital in Jakarta, Indonesia. Mothers filled out questionnaires about exposure to non-organophosphate household pesticides at the 3rd trimester of pregnancy. Birth weight and length were measured at birth. Afterwards, the weight, height, and head circumference (HC) were measured at 7 days, 1, 2, 4, and 6 months of age. Linear mixed modeling and linear regression was performed to calculate growth rate of each infant. Multivariable linear regression adjusted for confounders was used to assess the association between household pesticides exposure and birth sizes and infant growth rate.

Results

Based on self-report questionnaires, 133 (46.8%) mothers were exposed to household pesticides during pregnancy. The mean HC at day 7 in the exposed group was − 7.1 mm (95%CI -13.1;-1.2) lower than in the non-exposed group. The difference was more prominent in the non-mosquito pesticide group (linear regression coefficient: − 22.1 mm, 95%CI -36.5;-7.6). No material associations were found between antenatal exposure to household pesticides with other growth measures, including weight gain, length gain, HC increment and weight-to-length gain rates. No modification of effects by breastfeeding was found.

Conclusions

Our findings suggest that antenatal exposure to household non-organophosphate pesticides is associated with smaller head circumference at birth.

Prenatal exposure to pesticides and risk for holoprosencephaly: a case-control study

BACKGROUND

Pesticide exposure during susceptible windows and at certain doses are linked to numerous birth defects. Early experimental evidence suggests an association between active ingredients in pesticides and holoprosencephaly (HPE), the most common malformation of the forebrain in humans (1 in 250 embryos). No human studies to date have examined the association. This study investigated pesticides during multiple windows of exposure and fetal risk for HPE. It is hypothesized that pre-conception and early pregnancy, the time of brain development in utero, are the most critical windows of exposure.

METHODS

A questionnaire was developed for this retrospective case-control study to estimate household, occupational, and environmental pesticide exposures. Four windows of exposure were considered: preconception, early, mid and late pregnancy. Cases were identified through the National Human Genome Research Institute's ongoing clinical studies of HPE. Similarly, controls were identified as children with Williams-Beuren syndrome, a genetic syndrome also characterized by congenital malformations, but etiologically unrelated to HPE. We assessed for differences in odds of exposures to pesticides between cases and controls.

RESULTS

Findings from 91 cases and 56 controls showed an increased risk for HPE with reports of maternal exposure during pregnancy to select pesticides including personal insect repellants (adjusted odds ratio (aOR) 2.89, confidence interval (CI): 0.96-9.50) and insecticides and acaricides for pets (aOR 3.84, CI:1.04-16.32). Exposure to household pest control products during the preconception period or during pregnancy was associated with increased risk for HPE (aOR 2.60, OR: 0.84-8.68). No associations were found for occupational exposures to pesticides during pregnancy (aOR: 1.15, CI: 0.11-11.42), although exposure rates were low. Higher likelihood for HPE was also observed with residency next to an agricultural field (aOR 3.24, CI: 0.94-12.31).

CONCLUSIONS

Observational findings are consistent with experimental evidence and suggest that exposure to personal, household, and agricultural pesticides during pregnancy may increase risk for HPE. Further investigations of gene by environment interactions are warranted.

Opportunities for evaluating chemical exposures and child health in the United States: the Environmental influences on Child Health Outcomes (ECHO) Program

The Environmental Influences on Child Health Outcomes (ECHO) Program will evaluate environmental factors affecting children's health (perinatal, neurodevelopmental, obesity, respiratory, and positive health outcomes) by pooling cohorts composed of >50,000 children in the largest US study of its kind. Our objective was to identify opportunities for studying chemicals and child health using existing or future ECHO chemical exposure data. We described chemical-related information collected by ECHO cohorts and reviewed ECHO-relevant literature on exposure routes, sources, and environmental and human monitoring. Fifty-six ECHO cohorts have existing or planned chemical biomonitoring data for mothers or children. Environmental phenols/parabens, phthalates, metals/metalloids, and tobacco biomarkers are each being measured by ≥15 cohorts, predominantly during pregnancy and childhood, indicating ample opportunities to study child health outcomes. Cohorts are collecting questionnaire data on multiple exposure sources and conducting environmental monitoring including air, dust, and water sample collection that could be used for exposure assessment studies. To supplement existing chemical data, we recommend biomonitoring of emerging chemicals, nontargeted analysis to identify novel chemicals, and expanded measurement of chemicals in alternative biological matrices and dust samples. ECHO's rich data and samples represent an unprecedented opportunity to accelerate environmental chemical research to improve the health of US children.

Nano-curcumin versus curcumin in amelioration of deltamethrin-induced hippocampal damage

We aimed to prove that oxidative stress is the main mechanism responsible for hippocampal neurotoxicity induced by deltamethrin (DLM). The protective role of curcumin (CMN) and nano-curcumin (NCMN) over this toxicity was studied. The rats were categorized into four groups: control, DLM, CMN and NCMN. The study continued for 30 days. Hippocampus was processed for histological, biochemical and immunohistochemical studies. Caspase-3, glial fibrillar acidic protein (GFAP), acetylcholinesterase (AChE), malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) were measured for DLM-induced oxidative stress (increased MDA by 354%/decreased GSH by 61%, SOD by 61%, CAT 57%). Oxidative stress induced apoptosis of hippocampal neurons through increasing Nrf2, gamma-glutamyl cysteine synthetase heavy subunit (GCS-HS) and light subunit (GCS-LS) and decreasing AChE. It increases the activity of astrocytes through increasing GFAP. Finally, oxidative stress has a bad impaction on cognitive function. Improvement of oxidative stress was observed with use of CMN and NCMN (decrease of MDA/increase of GSH, SOD, CAT). The level of Nrf2, GCS-HS and GCS-LS decreased, while AChE, GFAP increased. Improvement of cognitive function was observed in both groups. In conclusion, oxidative stress is the common mechanism responsible for DLM-induced hippocampal neurotoxicity. It exerts apoptosis of hippocampal neurons through increasing Nrf2, HS-GCS, LS-GCS and decreasing AChE. In addition, it activates astrocytes through increasing expression of GFAP. The protective role of CMN and CMMN is related to their potent antioxidant effect. Much improvement has been detected with NCMN as compared to CMN.

Toxic effect of alpha cypermethrin, an environmental pollutant, on myocardial tissue in male wistar rats

α-Cypermethrin (CYP) is a pyrethroid insecticide-like environmental pollutant, widely found in the environment. New research links exposure to high levels of CYP to health damage; however, little is known about the effect of CYP on cardiovascular disease. The purpose of the present study was to evaluate, for the first time, biochemical and cardiovascular changes in male rats resulting from subchronic CYP exposure. The animals were divided into three groups: group 1 served as the control, group 2 (CYP1) received 4 mg/kg of CYP by gavage, and group 3 (CYP2) received 8 mg/kg of CYP by gavage, for 8 weeks each. Results showed that both CYP1 and CYP2 markedly increased plasma concentrations of cardiac markers (LDH, CK-MB, and troponin-T). Moreover, compared to the control group, CYP treatment elevated cardiac oxidative stress, as shown by increased MDA level and decreased activity of SOD, CAT, and GSH-Px. In addition, CYP2 caused a significant increase of 42% the concentration of total cholesterol and more than 75% in triglycerides compared to the control group. Furthermore, DNA fragmentation and collagen deposition were both amplified owing to CYP toxicity. This harmful effect was confirmed by a histological study using H-E and Sirius Red staining. Overall, our results clearly proved the cardiotoxicity caused by α-cypermethrin.

Toxicokinetics of cis- and trans-Permethrin: Influence of Isomer, Maturation, and Sex

Permethrin exposure of children and adults is widespread in many populations, but knowledge of its relative toxicokinetics (TK) and health risks in immature age groups is lacking. Studies were conducted in rats to determine the influence of immaturity and sex (on plasma and target organ dosimetry of each of the insecticide’s 2 isomers, cis- and trans-permethrin [CIS and TRANS]). Postnatal day 15, 21, and 90 (adult), Sprague Dawley rats were orally administered a graduated series of doses of CIS and TRANS in corn oil. Serial sacrifices were conducted over 24 h to obtain plasma, brain, liver, skeletal muscle, and fat profiles of CIS and TRANS. Levels of TRANS decreased relatively rapidly, despite administration of relatively high doses. Concentrations of each isomer in plasma, brain, and other tissues monitored were inversely proportional to the animals’ age. The youngest pups exhibited 4-fold higher plasma and brain area under the curves than did adults. Little difference was observed in the TK of CIS or TRANS between adult male and female rats, other than higher initial plasma and liver CIS levels in females. Elevated exposure of the immature brain appears to be instrumental in increased susceptibility to the acute neurotoxicity of high-dose permethrin (Cantalamessa [1993]), but it remains to be established whether age-dependent TK is relevant to long-term, low-level risks.

Changes in Indoor Insecticide Residue Levels after Adopting an Integrated Pest Management Program to Control German Cockroach Infestations in an Apartment Building

Insecticide use in homes leads to human exposure to insecticide residues that persist in the environment. Integrated pest management (IPM) programs have been known to be more environmentally friendly for managing German cockroach (Blattella germanica L.) infestations, but their effect on indoor insecticide residue levels are not well understood. An IPM program consisting of applying cockroach gel baits and placing insect sticky traps as the primary treatment methods were implemented. Floor wipe samples were collected from the bedroom and kitchen floors of 69 apartments with German cockroach infestations at 0 months and again at 12 months from 49 of the 69 apartments sampled at 0 months. Levels of 18 insecticide residues were measured. The mean insecticide residue concentration per apartment decreased by 74% after 12 months. The number of insecticides detected per apartment decreased from 2.5 ± 0.2 to 1.5 ± 0.2 (mean ± standard error). Indoxacarb residue was only detected in two apartments at 12 months despite the fact that an average of 32 ± 4 g 0.6% indoxacarb gel bait was applied per apartment. IPM implementation can result in significant reduction in the insecticide residue concentrations and number of detected insecticides in floor dust samples.

Pesticide interactions and risks of sperm chromosomal abnormalities

Disentangling the separate and synergistic effects of chemicals poses methodological challenges for accurate exposure assessment and for investigating epidemiologically how chemicals affect reproduction. We investigated combined exposures to ubiquitous contemporary use pesticides, specifically organophosphates (OP) and pyrethroids (PYR), and their association with germ cell abnormalities among adult men. Fluorescence in situ hybridization was used to determine disomy in sperm nuclei and urine was analyzed for concentrations of PYR metabolites (3-phenoxybenzoic acid; 3PBA) and OP dialkyl phosphate (DAP) metabolites. Incidence rate ratios using Poisson models were estimated for each disomy type by exposure quartile of DAP metabolites and 3PBA, controlling for confounders. The shape of the associations between PYRs, OPs and disomy were frequently nonmonotonic. There were consistent interactions between OP and PYR metabolite concentrations and the risk for sperm abnormalities. Taking both chemicals into account simultaneously resulted in quantitatively different associations than what was reported previously for OPs and PYRs separately, demonstrating the importance of modeling multiple concentrations simultaneously. Methods investigating interactions using Poisson models are needed to better quantify chemical interactions and their effects on count-based health outcomes, the importance of which was shown here for germ cell abnormalities.

Gut microbiota: An underestimated and unintended recipient for pesticide-induced toxicity

Pesticide pollution residues have become increasingly common health hazards over the last several decades because of the wide use of pesticides. The gastrointestinal tract is the first physical and biological barrier to contaminated food and is therefore the first exposure site. Interestingly, a number of studies have shown that the gut microbiota plays a key role in the toxicity of pesticides and has a profound relationship with environmental animal and human health. For instance, intake of the pesticide of chlorpyrifos can promote obesity and insulin resistance through influencing gut and gut microbiota of mice. In this review, we discussed the possible effects of different kinds of widely used pesticides on the gut microbiota in different experimental models and analyzed their possible subsequent effects on the health of the host. More and more studies indicated that the gut microbiota of animals played a very important role in pesticides-induced toxicity, suggesting that gut micriobita was also the unintended recipient of pesticides. We hope that more attention can focus on the relationship between pesticides, gut microbiota and environmental health risk assessment in near future.

Deltamethrin Exposure Daily From Postnatal Day 3-20 in Sprague-Dawley Rats Causes Long-term Cognitive and Behavioral Deficits

Pyrethroids are synthetic insecticides that act acutely on voltage gated sodium channels to prolong channel opening and depolarization. Epidemiological studies find that exposure to pyrethroids are associated with neurological and developmental abnormalities in children. The long-term effects of type II pyrethroids, such as deltamethrin (DLM), on development have received little attention. We exposed Sprague-Dawley rats to DLM by gavage at doses of 0, 0.25, 0.5, and 1.0 mg/kg/day from postnatal day (P) 3-20 in a split-litter design. Following behavioral testing as adults, monoamine levels, release, and mRNA were assessed via high performance liquid chromatography, microdialysis, and qPCR, respectively. Long-term potentiation (LTP) was assessed at P25-35. Developmental DLM exposure resulted in deficits in allocentric and egocentric learning and memory, increased startle reactivity, reduced conditioned contextual freezing, and attenuated MK-801 induced hyperactivity compared with controls. Startle and egocentric learning were preferentially affected in males. Deltamethrin-treated rats exhibited increased CA1 hippocampal LTP, decreased extracellular dopamine release by microdialysis, reduced dopamine D1 receptor mRNA expression in neostriatum, and decreased norepinephrine levels in the hippocampus. The data indicate that neonatal DLM exposure has adverse long-term effects on learning, memory, startle, glutamatergic function, LTP, and norepinephrine.

Estimating the cumulative human exposures to pyrethroids by combined multi-route PBPK models: Application to the French population

Human biomarkers of exposure to pyrethroid insecticides are usually urinary concentrations of metabolites that can be specific to a pyrethroid or common to several compounds. We developed a global toxicokinetic model that links the external exposure to four widely-used pyrethroids and their isomers (deltamethrin and cis and trans isomers of permethrin, cypermethrin, and cyfluthrin) to the urinary concentrations of metabolites (cis- and trans-DCCA, 3-PBA, F-PBA and DBCA). This global model includes physiologically based pharmacokinetic models for each parent compound and one-compartment models for the metabolites. Existing in vivo, in vitro and in silico data were used for model calibration, and human toxicokinetic data for model evaluation. Overall, the global model reproduced the data accurately as about 90% of predictions were inside the 3-fold error interval. A sensitivity analysis showed that the most influent parameter for each urinary metabolite concentration was the fraction of parent compound that is transformed into that metabolite. The global model was then tested with realistic exposures for the French population: the predictions were consistent with biomonitoring data. The global model is a tool that will improve the interpretation of biomonitoring data for pyrethroids.

Organic diet intervention significantly reduces urinary pesticide levels in U.S. children and adults

BACKGROUND

Previous diet intervention studies indicate that an organic diet can reduce urinary pesticide metabolite excretion; however, they have largely focused on organophosphate (OP) pesticides. Knowledge gaps exist regarding the impact of an organic diet on exposure to other pesticides, including pyrethroids and neonicotinoids, which are increasing in use in the United States and globally.

OBJECTIVE

To investigate the impact of an organic diet intervention on levels of insecticides, herbicides, and fungicides or their metabolites in urine collected from adults and children.

METHODS

We collected urine samples from four racially and geographically diverse families in the United States before and after an organic diet intervention (n = 16 participants and a total of 158 urine samples).

RESULTS

We observed significant reductions in urinary levels of thirteen pesticide metabolites and parent compounds representing OP, neonicotinoid, and pyrethroid insecticides and the herbicide 2,4-D following the introduction of an organic diet. The greatest reductions were observed for clothianidin (- 82.7%; 95% confidence interval [95% CI]: - 86.6%, - 77.6%; p < 0.01), malathion dicarboxylic acid (MDA), a metabolite of malathion (- 95.0%; 95% CI: - 97.0%, - 91.8%; p < 0.01), and 3,5,6-trichlor-2-pyridinol (TCPy), a metabolite of chlorpyrifos (- 60.7%; 95% CI: - 69.6%, - 49.2%; p < 0.01). Metabolites or parent compounds of the fungicides boscalid, iprodione, and thiabendazole and the neonicotinoid insecticide imidacloprid were not detected among participants in our study.

CONCLUSION

An organic diet was associated with significant reductions in urinary excretion of several pesticide metabolites and parent compounds. This study adds to a growing body of literature indicating that an organic diet may reduce exposure to a range of pesticides in children and adults. Additional research is needed to evaluate dietary exposure to neonicotinoids, which are now the most widely used class of insecticides in the world.

Toxicokinetics of Deltamethrin: Dosage Dependency, Vehicle Effects, and Low-Dose Age-Equivalent Dosimetry in Rats

There is increasing concern that infants and children may be at increased risk of neurological effects of pyrethroids, the most widely used class of insecticide. The objectives of this investigation were to (1) characterize the dose-dependent toxicokinetics (TK) of deltamethrin (DLM) for exposures ranging from environmentally relevant to acutely toxic; (2) determine the influence of an aqueous versus oil vehicle on oral absorption and bioavailability; and (3) determine whether DLM exhibits low-dose, age-equivalent internal dosimetry. Serial arterial plasma samples were obtained for 72 h from adult, male Sprague Dawley rats given 0.05-5.0 mg DLM/kg as an oral bolus in corn oil (CO). DLM exhibited linear, absorption rate-limited TK. Increases in maximum plasma concentration (Cmax) and AUC∘∞ were directly proportional to the dose. Oral bioavailability was quite limited. The vehicle and its volume had modest effect on the rate and extent of systemic absorption in adult rats. Postnatal day (PND) 15, 21, and 90 (adult) rats received 0.10, 0.25, or 0.50 mg DLM/kg orally in CO and were sacrificed periodically for plasma, brain, and liver collection. Age-dependent differences between PND 15 and 90 plasma Cmax and AUC∘24 values progressively diminished as the dose decreased, but there was a lack of low dose age equivalence in these brain and liver dosimeters. Other maturational factors may account for the lack of the low-dose age equivalence in brain and liver. This investigation provides support for the premise that the relatively low metabolic capacity of immature subjects may be adequate to effectively eliminate trace amounts of DLM and other pyrethroids from the plasma.

Urinary levels of pyrethroid pesticides and determinants in pregnant French women from the Elfe cohort

Pyrethroids are insecticides which are widely used for agricultural and domestic purposes. The general population can be exposed to them. Given the suspected effects of pesticides on the development of the foetus, exposure to pyrethroids during pregnancy is a major public health concern. The objective of this paper is to describe the urinary levels of the following five pyrethroid metabolites and their associated determinants among pregnant French women in 2011 enrolled in the Elfe cohort (n = 1077): a) 3-phenoxy benzoic (3-PBA), b) 4‑fluoro‑3‑phenoxy benzoic acid (4-F-3-PBA), c) Cis‑3‑(2,2dibromovinyl)‑2,2‑dimethyl cyclopropane-carboxylic acid (Cis-DBCA); d) Cis‑3‑(2,2dichlorovinyl)‑2,2‑dimethyl cyclopropane-carboxylic acid (Cis-DCCA) and e) Trans-3‑(2,2dichlorovinyl)‑2,2‑dimethyl cyclopropane-carboxylic acid (Trans-DCCA). The distribution levels were estimated for each pyrethroid metabolite. Multivariable analyses helped determine the predictors of these levels. All metabolites except 4-F-3-PBA were detected in all the urine samples. The mean urinary concentration of the sum of the metabolites (3-PBA, Cis-DBCA, Cis-DCCA, Trans-DCCA) was 1.18 μg/L, with the highest concentrations observed for 3-PBA. A comparison of these levels with other studies showed that pregnant French women tend to be more exposed to pyrethroids than their American counterparts, less exposed than Chinese and Caribbean mothers, and have similar exposure to Japanese mothers. In our study, urinary levels of pyrethroid metabolites were positively related to smoking during pregnancy, consuming fish and alcohol, domestic pesticide use and living in the vicinity of crops during pregnancy. These findings highlight the importance of non-dietary pathways when evaluating exposure to pyrethroids.

Farmworker and nonfarmworker Latino immigrant men in North Carolina have high levels of specific pesticide urinary metabolites

This article compares detections and concentrations of specific organophosphate (OP), bis-dithiocarbamate, and pyrethroid pesticide urinary metabolites among Latino male farmworkers and nonfarmworkers in North Carolina. Data are from interviews and urine samples collected in 2012 and 2013. Farmworkers and nonfarmworkers frequently had detections for OP and pyrethroid pesticide urinary metabolites. Detection of bis-dithiocarbamate urinary metabolites was less frequent, but substantial among the nonfarmworkers. The concentrations of organophosphate, bis-dithiocarbamate, and pyrethroid pesticide urinary metabolites were high for farmworkers and nonfarmworkers compared to National Health and Nutrition Examination Survey results. Pesticide urinary metabolite detection was not associated with occupation in nonfarmworkers. Research for reducing pesticide exposure among farmworkers remains important; research is also needed to determine pesticide exposure pathways among Latino nonfarmworkers.

Pest Prevalence and Evaluation of Community-Wide Integrated Pest Management for Reducing Cockroach Infestations and Indoor Insecticide Residues

Pest infestations in residential buildings are common, but community-wide pest survey data are lacking. Frequent insecticide applications for controlling indoor pests leave insecticide residues and pose potential health risks to residents. In this study, a community-wide pest survey was carried out in a housing complex consisting of 258 units in 40 buildings in New Brunswick, New Jersey. It was immediately followed by implementation of an integrated pest management (IPM) program in all the cockroach-infested apartments and two bed bug apartments with the goal of eliminating pest infestations, reducing pyrethroid residues, and increasing resident satisfaction with pest control services. The IPM-treated apartments were revisited and treated biweekly or monthly for 7 mo. Initial inspection found the top three pests and their infestation rates to be as follows: German cockroaches (Blattella germanica L. [Blattodea: Blattellidae]), 28%; rodents, 11%; and bed bugs (Cimex lectularius L. [Hemiptera: Cimicidae]), 8%. Floor wipe samples were collected in the kitchens and bedrooms of 20 apartments for pyrethroid residue analysis before the IPM implementation; 17 of the 20 apartments were resampled again at 7 mo. The IPM program reduced cockroach counts per apartment by 88% at 7 wk after initial treatment. At 7 mo, 85% of the cockroach infestations found in the initial survey were eliminated. The average number of pyrethroids detected decreased significantly from 6 ± 1 (mean ± SEM) and 5 ± 1 to 2 ± 1 and 3 ± 1 in the kitchens and bedrooms, respectively. The average concentrations of targeted pyrethroids residue also decreased significantly in the kitchens and bedrooms.

Pyrethroid pesticide residues in the global environment: An overview

Pyrethroids are synthetic organic insecticides with low mammalian toxicity that are widely used in both rural and urban areas worldwide. After entering the natural environment, pyrethroids circulate among the three phases of solid, liquid, and gas and enter organisms through food chains, resulting in substantial health risks. This review summarized the available studies on pyrethroid residues since 1986 in different media at the global scale and indicated that pyrethroids have been widely detected in a range of environments (including soils, water, sediments, and indoors) and in organisms. The concentrations and detection rates of agricultural pyrethroids, which always contain α-cyanogroup (α-CN), such as cypermethrin and fenvalerate, decline in the order of crops > sediments > soils > water. Urban pyrethroids (not contain α-CN), such as permethrin, have been detected at high levels in the indoor environment, and 3-phenoxybenzoic acid, a common pyrethroid metabolite in human urine, is frequently detected in the human body. Pyrethroid pesticides accumulate in sediments, which are a source of pyrethroid residues in aquatic products.

Assessment of complex water pollution with heavy metals and Pyrethroid pesticides on transcript levels of metallothionein and immune related genes

Alteration of immunological function of an aquatic organism can be used as an indicator for evaluating the direct effect of exposure to pollutants. The aim of this work is to assess the impact of complex water pollution with special reference to Pyrethroid pesticides and heavy metals on mRNA transcript levels of Metallothionine and some immune related genes of Nile tilapia (Oreochromas Niloticus). Residues of six heavy metals and six Pyrethroid were assessed in water as well as fish tissues at three different sites of Lake Burullus, located at Northern Egypt. Variations of water physicochemical properties associated with different levels of heavy metals at the three different sections were recorded. Tissue residues of Fe, Mn and Zn, Cu, Ni exceed water levels in contrast to elevated water level of Pb. All assessed Pyrethroids are detected in fish tissue samples with higher concentration (3-42 folds) than that found in water samples especially Cypermethrin. Significant down-regulation of expression levels of metallothionein (MT) at the three sections of the lake was observed. The expression of immune related genes (IgM) and inflammatory cytokines (TNF, IL.8 and IL.1) were affected. IgM and TNF were significantly down-regulated at eastern and western section of the lake; meanwhile the expression of IL8 is down regulated at the three sections of the lack. IL1 was significantly up-regulated at eastern and middle sections. We conclude that, variable gene expression of MT and immune-related genes at the three sections of the lack impose different response to complex water pollution in relation to variable aquatic environment.

Prenatal exposure to lambda-cyhalothrin alters brain dopaminergic signaling in developing rats

The present study is focused to decipher the molecular mechanisms associated with dopaminergic alterations in corpus striatum of developing rats exposed prenatally to lambda-cyhalothrin (LCT), a new generation type II synthetic pyrethroid. There was no significant change in the mRNA and protein expression of DA-D1 receptors at any of the doses of LCT (0.5, 1 and 3mg/kg body weight) in corpus striatum of developing rats exposed prenatally to LCT on PD22 and PD45. Prenatal exposure to LCT (1 and 3mg/kg body weight) resulted to decrease the levels of mRNA and protein of DA-D2 receptors in corpus stratum of developing rats on PD22 as compared to controls. Decrease in the binding of 3H-Spiperone in corpus striatum, known to label DA-D2 receptors was also distinct in developing rats on PD22. These rats also exhibited decrease in the expression of proteins - TH, DAT and VMAT2 involved in pre-dopaminergic signaling. Further, decrease in the expression of DARPP-32 and pCREB associated with increased expression of PP1α was evident in developing rats on PD22 as compared to controls. Interestingly, a trend of recovery in the expression of these proteins was observed in developing rats exposed to LCT at moderate dose (1.0mg/kg body weight) while alteration in the expression of these proteins continued to persist in those exposed at high dose (3.0mg/kg body weight) on PD45 as compared to respective controls. No significant change in the expression of any of these proteins was observed in corpus striatum of developing rats prenatally exposed to LCT at low dose (0.5mg/kg body weight) on PD22 and PD45 as compared to respective controls. The results provide interesting evidence that alterations in dopaminergic signaling on LCT exposure are due to selective changes in DA-D2 receptors in corpus striatum of developing rats. Further, these changes could be attributed to impairment in spontaneous motor activity on LCT exposure in developing rats.

Effects of an environmentally-relevant mixture of pyrethroid insecticides on spontaneous activity in primary cortical networks on microelectrode arrays

Pyrethroid insecticides exert their insecticidal and toxicological effects primarily by disrupting voltage-gated sodium channel (VGSC) function, resulting in altered neuronal excitability. Numerous studies of individual pyrethroids have characterized effects on mammalian VGSC function and neuronal excitability, yet studies examining effects of complex pyrethroid mixtures in mammalian neurons, especially in environmentally relevant mixture ratios, are limited. In the present study, concentration-response functions were characterized for five pyrethroids (permethrin, deltamethrin, cypermethrin, β-cyfluthrin and esfenvalerate) in an in vitro preparation containing cortical neurons and glia. As a metric of neuronal network activity, spontaneous mean network firing rates (MFR) were measured using microelectorde arrays (MEAs). In addition, the effect of a complex and exposure relevant mixture of the five pyrethroids (containing 52% permethrin, 28.8% cypermethrin, 12.9% β-cyfluthrin, 3.4% deltamethrin and 2.7% esfenvalerate) was also measured. Data were modeled to determine whether effects of the pyrethroid mixture were predicted by dose-addition. At concentrations up to 10μM, all compounds except permethrin reduced MFR. Deltamethrin and β-cyfluthrin were the most potent and reduced MFR by as much as 60 and 50%, respectively, while cypermethrin and esfenvalerate were of approximately equal potency and reduced MFR by only ∼20% at the highest concentration. Permethrin caused small (∼24% maximum), concentration-dependent increases in MFR. Effects of the environmentally relevant mixture did not depart from the prediction of dose-addition. These data demonstrate that an environmentally relevant mixture caused dose-additive effects on spontaneous neuronal network activity in vitro, and is consistent with other in vitro and in vivo assessments of pyrethroid mixtures.

Urinary Concentrations of Insecticide and Herbicide Metabolites among Pregnant Women in Rural Ghana: A Pilot Study

Use of pesticides by households in rural Ghana is common for residential pest control, agricultural use, and for the reduction of vectors carrying disease. However, few data are available about exposure to pesticides among this population. Our objective was to quantify urinary concentrations of metabolites of organophosphate (OP), pyrethroid, and select herbicides during pregnancy, and to explore exposure determinants. In 2014, 17 pregnant women from rural Ghana were surveyed about household pesticide use and provided weekly first morning urine voids during three visits (n = 51 samples). A total of 90.1% (46/51) of samples had detectable OP metabolites [geometric mean, GM (95% CI): 3,5,6-trichloro-2-pyridinol 0.54 µg/L (0.36–0.81), para-nitrophenol 0.71 µg/L (0.51–1.00)], 75.5% (37/49) had detectable pyrethroid metabolites [GM: 3-phenoxybenzoic acid 0.23 µg/L (0.17, 0.32)], and 70.5% (36/51) had detectable 2,4-dichlorophenoxyacetic acid levels, a herbicide [GM: 0.46 µg/L (0.29–0.73)]. Concentrations of para-nitrophenol and 2,4-dichlorophenoxyacetic acid in Ghanaian pregnant women appear higher when compared to nonpregnant reproductive-aged women in a reference U.S. population. Larger studies are necessary to more fully explore predictors of exposure in this population.

Assessment of the inhibitory effects of pyrethroids against human carboxylesterases

Pyrethroids are broad-spectrum insecticides that widely used in many countries, while humans may be exposed to these toxins by drinking or eating pesticide-contaminated foods. This study aimed to investigate the inhibitory effects of six commonly used pyrethroids against two major human carboxylesterases (CES) including CES1 and CES2. Three optical probe substrates for CES1 (DME, BMBT and DMCB) and a fluorescent probe substrate for CES2 (DDAB) were used to characterize the inhibitory effects of these pyrethroids. The results demonstrated that most of the tested pyrethroids showed moderate to weak inhibitory effects against both CES1 and CES2, but deltamethrin displayed strong inhibition towards CES1. The IC₅₀ values of deltamethrin against CES1-mediated BMBT, DME, and DMCB hydrolysis were determined as 1.58μM, 2.39μM, and 3.3μM, respectively. Moreover, deltamethrin was cell membrane permeable and capable of inhibition endogenous CES1 in living cells. Further investigation revealed that deltamethrin inhibited CES1-mediated BMBT hydrolysis via competitive manner but noncompetitively inhibited DME or DMCB hydrolysis. The inhibition behaviors of deltamethrin against CES1 were also studied by molecular docking simulation. The results demonstrated that CES1 had at least two different ligand-binding sites, one was the DME site and another was the BMBT site which was identical to the binding site of deltamethrin. In summary, deltamethrin was a strong reversible inhibitor against CES1 and it could tightly bind on CES1 at the same ligand-binding site as BMBT. These findings are helpful for the deep understanding of the interactions between xenobiotics and CES1.

Developmental neurotoxicity of succeeding generations of insecticides

Insecticides are by design toxic. They must be toxic to effectively kill target species of insects. Unfortunately, they also have off-target toxic effects that can harm other species, including humans. Developmental neurotoxicity is one of the most prominent off-target toxic risks of insecticides. Over the past seven decades several classes of insecticides have been developed, each with their own mechanisms of effect and toxic side effects. This review covers the developmental neurotoxicity of the succeeding generations of insecticides including organochlorines, organophosphates, pyrethroids, carbamates and neonicotinoids. The goal of new insecticide development is to more effectively kill target species with fewer toxic side effects on non-target species. From the experience with the developmental neurotoxicity caused by the generations of insecticides developed in the past advice is offered how to proceed with future insecticide development to decrease neurotoxic risk.

Neurodevelopmental Delay Diagnosis Rates Are Increased in a Region with Aerial Pesticide Application

A number of studies have implicated pesticides in childhood developmental delay (DD) and autism spectrum disorder (ASD). The influence of the route of pesticide exposure on neurodevelopmental delay is not well defined. To study this factor, we examined ASD/DD diagnoses rates in an area near our regional medical center that employs yearly aerial pyrethroid pesticide applications to combat mosquito-borne encephalitis. The aim of this study was to determine if areas with aerial pesticide exposure had higher rates of ASD/DD diagnoses. This regional study identified higher rates of ASD/DD diagnoses in an area with aerial pesticides application. Zip codes with aerial pyrethroid exposure were 37% more likely to have higher rates of ASD/DD (adjusted RR = 1.37, 95% CI = 1.06-1.78, p = 0.02). A Poisson regression model controlling for regional characteristics (poverty, pesticide use, population density, and distance to medical center), subject characteristics (race and sex), and local birth characteristics (prematurity, low birthweight, and birth rates) identified a significant relationship between aerial pesticide use and ASD/DD rates. The relationship between pesticide application and human neurodevelopment deserves additional study to develop safe and effective methods of mosquito prevention, particularly as communities develop plans for Zika virus control.

Self-reported pregnancy exposures and placental DNA methylation in the MARBLES prospective autism sibling study

Human placenta is a fetal-derived tissue that offers a unique sample of epigenetic and environmental exposures present in utero. In the MARBLES prospective pregnancy study of high-risk younger siblings of children with autism spectrum disorder (ASD), pregnancy and environmental factors collected by maternal interviews were examined as predictors of placental DNA methylation, including partially methylated domains (PMDs), an embryonic feature of the placental methylome. DNA methylation data from MethylC-seq analysis of 47 placentas of children clinically diagnosed at 3 years with ASD or typical development using standardized assessments were examined in relation to: child's gestational age, birth-weight, and diagnosis; maternal pre-pregnancy body mass index, smoking, education, parity, height, prenatal vitamin and folate intake; home ownership; pesticides professionally applied to lawns or gardens or inside homes, pet flea/tick pouches, collars, or soaps/shampoos used in the 3 months prior to or during pregnancy. Sequencing run, order, and coverage, and child race and sex were considered as potential confounders. Akaike information criterion was used to select the most parsimonious among candidate models. Final prediction models used sandwich estimators to produce homoscadisticity-robust estimates of the 95% confidence interval (CI) and P-values controlled the false discovery rate at 5%. The strongest, most robust associations were between pesticides professionally applied outside the home and higher average methylation over PMDs [0.45 (95% CI 0.17, 0.72), P = 0.03] and a reduced proportion of the genome in PMDs [-0.42 (95% CI - 0.67 to -0.17), P = 0.03]. Pesticide exposures could alter placental DNA methylation more than other factors.

Childhood Leukemia: A Preventable Disease

In contrast to most pediatric cancers, there is a growing body of literature, nationally and internationally, that has implicated the role of several environmental indoor and outdoor hazards in the etiology of childhood leukemia. For example, exposures to solvents, traffic, pesticides, and tobacco smoke have consistently demonstrated positive associations with the risk of developing childhood leukemia. Intake of vitamins and folate supplementation during the preconception period or pregnancy has been demonstrated to have a protective effect. Despite the strength of these findings, the dissemination of this knowledge to clinicians has been limited. Some children may be more vulnerable than others as documented by the high and increasing incidence of childhood leukemia in Hispanics. To protect children's health, it is prudent to establish programs to alter exposure to those factors with well-established associations with leukemia risk rather than to suspend judgment until no uncertainty remains. This is particularly true because other serious health outcomes (both negative and positive) have been associated with the same exposures. We draw from historical examples to put in perspective the arguments of association versus causation, as well as to discuss benefits versus risks of immediate and long-term preventive actions.