Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

Estro-Androgenic Disrupting Effects of Halogenated Disinfection Byproducts: A Comprehensive Evaluation and Comparison

Drinking water halogenated disinfection byproducts (DBPs) have become an increasing health concern. However, the endocrine-disrupting effects of DBPs have not been well evaluated, and the limited available data have inhibited a comprehensive understanding of their health risks. In this study, a total of 43 DBPs were evaluated for their estro-androgenic effects using two types of human breast cancer cells. Among the tested DBPs, 16 exhibited estrogenic/antiestrogenic/androgenic/antiandrogenic effects, and the effects could be observed even at concentrations typically detected in drinking water. Iodinated and polyhalogenated DBPs generally showed higher effects than other species. For a broader comparison, DBP endocrine-disrupting effect data from this study and previous studies were summarized. It was found that the endocrine disruption efficacy of DBPs followed the rank order of iodinated > brominated > chlorinated species, and halophenolic DBPs were potential endocrine-disrupting compounds. Moreover, molecular docking results demonstrated that the binding of DBPs to estro-androgenic receptors was dominated by hydrophobic bonding, hydrogen bonding, halogen bonding, and van der Waals forces. The force strength and molecular volume were related to the magnitude of the estro-androgenic effects. Iodinated DBPs and polyhalogenated DBPs tended to have larger binding forces than other analogues and thus exhibited stronger effects.

Antioxidant cysteine and methionine derivatives show trachea disruption in insects

To prevent the deterioration of the global environment, the reduction of chemical pesticide use and the development of eco-friendly pest control technologies are urgent issues. Our recent study revealed that the production of reactive oxygen species (ROS) by dual oxidase (Duox) plays a pivotal role in stabilizing the tracheal network by intermediating the tyrosine cross-linking of proteins that constitute trachea. Notably, the formation of dityrosine bonds by ROS can be inhibited by the intake of an antioxidant cysteine derivative N-acetyl-L-cysteine (NAC), which can suppress insect respiration. In this study, we screened for the derivatives showing insecticidal activity and tracheal formation inhibition. As a result of investigating the soybean pest bug Riptortus pedestris, cysteine and methionine derivatives showed respiratory formation inhibition and high insecticidal activity. In particular, NAC had a slow-acting insecticidal effect, while L-cysteine methyl ester (L-CME) showed relatively fast-acting insecticidal activity. Furthermore, the insecticidal activity of these derivatives was also detected in Drosophila, mealworms, cockroaches, termites, and plant bugs. Our results suggest that some antioxidant compounds have specific tracheal inhibitory activity in different insect species and they may be used as novel pest control agents upon further characterization.

Estrogenic compounds in drinking water: A systematic review and risk analysis

Estrogenic compounds are the endocrine disruptors that receive major attention because of their ability to imitate the natural female hormone, 17β-estradiol and cause adverse effects on the reproductive system of animals. The presence of estrogenic compounds in drinking water is a warning to assess the risks to which human beings are exposed. The present work has the objectives of carrying out a systematic review of studies that investigated estrogenic compounds in drinking water around the world and estimate the human health and estrogenic activity risks, based on the concentrations of each compound reported. The systematic review returned 505 scientific papers from the Web of Science®, SCOPUS® and PubMED® databases and after careful analysis, 45 papers were accepted. Sixteen estrogenic compounds were identified in drinking water, from the classes of hormones, pharmaceutical drugs and personal care products, plasticizers, corrosion inhibitors, pesticides and surfactants. Di-(2-ethylhexyl) phthalate (DEHP) was the compound found at the highest concentration, reaching a value of 1.43 mg/L. Non-carcinogenic human health risk was classified as high for 17α-ethynilestradiol and DEHP, medium for dibutyl phthalate, and low for bisphenol A. The estrogenic activity risks were negligible for all the compounds, except DEHP, with a low risk. None of the estrogenic compounds presented an unacceptable carcinogenic risk, due to estrogenic activity. However, the risk assessment did not evaluate the interactions between compounds, that occurs in drinking water and can increase the risks and adverse effects to human health. Nonetheless, this study demonstrates the need for improvement of drinking water treatment plants, with more efficient technologies for micropollutant removal.

An Integrated Approach of Bioassays and Non-Target Screening for the Assessment of Endocrine-Disrupting Activities in Tap Water and Identification of Novel Endocrine-Disrupting Chemicals

The safety of drinking water is a significant environmental issue of great concern for human health since numerous contaminants are often detected in drinking water and its sources. Boiling is a common household method used to produce relatively high-quality drinking water in some countries and regions. In this study, with the aid of an integrated approach of in vitro bioassays and non-target analysis based on high-resolution mass spectrometry coupled with liquid chromatography, alterations in endocrine-disrupting activities in tap water samples without and with boiling were revealed, as well as the potential endocrine-disrupting chemicals (EDCs) contributing to these alterations were identified. The organic extracts of tap water had no significant (ant)agonistic activities against an estrogen receptor (ER), progesterone receptor (PR), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR) at enrichment concentrations of ≤10 times, posing no immediate or acute health risk to humans. However, the presence of agonistic activities against PR and MR and antagonistic activities against ER, PR, GR, and MR in OEs of tap water at relatively higher enrichment concentrations still raise potential health concerns. Boiling effectively reduced antagonistic activities against these steroid hormone receptors (SHRs) but increased estrogenic and glucocorticoid activities in drinking water. Four novel potential EDCs, including one UV filter (phenylbenzimidazole sulfonic acid, PBSA) and three natural metabolites of organisms (beta-hydroxymyristic acid, 12-hydroxyoctadecanoic acid, and isorosmanol) were identified in drinking water samples, each of which showed (ant)agonistic activities against different SHRs. Given the widespread use of UV filters in sunscreens to prevent skin cancer, the health risks posed by PBSA as an identified novel EDC are of concern. Although boiling has been thought to reduce the health risk of drinking water contamination, our findings suggest that boiling may have a more complex effect on the endocrine-disrupting activities of drinking water and, therefore, a more comprehensive assessment is needed.

A pilot study of chlormequat in food and urine from adults in the United States from 2017 to 2023

Chlormequat chloride is a plant growth regulator whose use on grain crops is on the rise in North America. Toxicological studies suggest that exposure to chlormequat can reduce fertility and harm the developing fetus at doses lower than those used by regulatory agencies to set allowable daily intake levels. Here we report, the presence of chlormequat in urine samples collected from people in the U.S., with detection frequencies of 69%, 74%, and 90% for samples collected in 2017, 2018-2022, and 2023, respectively. Chlormequat was detected at low concentrations in samples from 2017 through 2022, with a significant increase in concentrations for samples from 2023. We also observed high detection frequencies of chlormequat in oat-based foods. These findings and chlormequat toxicity data raise concerns about current exposure levels, and warrant more expansive toxicity testing, food monitoring, and epidemiological studies to assess health effects of chlormequat exposures in humans. IMPACT: This study reports the detection of chlormequat, an agricultural chemical with developmental and reproductive toxicity, in the U.S. population and U.S. food supplies for the first time. While similar levels of the chemical were found in urine sampled from 2017 to 2022, markedly increased levels were found in samples from 2023. This work highlights the need for more expansive monitoring of chlormequat in U.S. foods and in human specimens, as well as toxicological and epidemiological study on chlormequat, as this chemical is an emerging contaminant with documented evidence of low-dose adverse health effects in animal studies.

An updated status of currently used pesticides in India: Human dietary exposure from an Indian food basket

Currently used pesticides (CUPs) were introduced to have lower persistence and bioaccumulation, and lesser bioavailability towards non-target species. Nevertheless, CUPs still represent a concern for both human health and the environment. India is an important agricultural country experiencing a conversion from the use of obsolete organochlorine pesticides to a newer generation of phytosanitary products. As for other developing countries, very little is known about the transfer of CUPs to the human diet in India, where systematic monitoring is not in place. In this study, we analyzed ninety four CUPs and detected thirty CUPs in several food products belonging to five types: cereals and pulses, vegetables, fruits, animal-based foods, and water. Samples were taken from markets in Delhi (aggregating food produced all over India) and in the periurban area of Dehradun (northern India) (representing food produced locally and through more traditional practices). Overall, chlorpyrifos and chlorpropham were the most detected CUPs with a detection frequency of 33% and 25%, respectively. Except for vegetables and fruits, the levels of CUPs in all other food types were significantly higher in samples from Delhi (p < 0.05). Exposure dosage of CUPs through different food matrices was calculated, and chlorpropham detected in potatoes had the maximum exposure dosage to humans (2.46 × 10-6 mg/kg/day). Risk analysis based on the hazard quotient technique indicated that chlorpyrifos in rice (2.76 × 10-2) can be a concern.

Impaired spermatogenesis and associated endocrine effects of azole fungicides in peripubertal Xenopus tropicalis

Early life exposure to endocrine disrupting chemicals (EDCs) has been suggested to adversely affect reproductive health in humans and wildlife. Here, we characterize endocrine and adverse effects on the reproductive system after juvenile exposure to propiconazole (PROP) or imazalil (IMZ), two common azole fungicides with complex endocrine modes of action. Using the frog Xenopus tropicalis, two short-term (2-weeks) studies were conducted. I: Juveniles (2 weeks post metamorphosis (PM)) were exposed to 0, 17 or 178 µg PROP/L. II: Juveniles (6 weeks PM) were exposed to 0, 1, 12 or 154 µg IMZ/L. Histological analysis of the gonads revealed an increase in the number of dark spermatogonial stem cells (SSCs)/testis area, and in the ratio secondary spermatogonia: dark SSCs were increased in all IMZ groups compared to control. Key genes in gametogenesis, retinoic acid and sex steroid pathways were also analysed in the gonads. Testicular levels of 3β-hsd, ddx4 were increased and cyp19 and id4 levels were decreased in the IMZ groups. In PROP exposed males, increased testicular aldh1a2 levels were detected, but no histological effects observed. Although no effects on ovarian histology were detected, ovarian levels of esr1, rsbn1 were increased in PROP groups, and esr1 levels were decreased in IMZ groups. In conclusion, juvenile azole exposure disrupted testicular expression of key genes in retinoic acid (PROP) and sex steroid pathways and in gametogenesis (IMZ). Our results further show that exposure to environmental concentrations of IMZ disrupted spermatogenesis in the juvenile testis, which is a cause for concern as it may lead to impaired fertility. Testicular levels of id4, ddx4 and the id4:ddx4 ratio were associated with the number of dark SSCs and secondary spermatogonia suggesting that they may serve as a molecular markers for disrupted spermatogenesis.

In vitro exposure to triazoles used as fungicides impairs human granulosa cells steroidogenesis

Triazoles are the main components of fungicides used in conventional agriculture. Some data suggests that they may be endocrine disruptors. Here, we found five triazoles, prothioconazole, metconazole, difenoconazole, tetraconazole, and cyproconazole, in soil or water from the Centre-Val de Loire region of France. We then studied their effects from 0.001 µM to 1000 µM for 48 h on the steroidogenesis and cytotoxicity of ovarian cells from patients in this region and the human granulosa line KGN. In addition, the expression of the aryl hydrocarbon receptor (AHR) nuclear receptor in KGN cells was studied. Overall, all triazoles reduced the secretion of progesterone, estradiol, or both at doses that were non-cytotoxic but higher than those found in the environment. This was mainly associated, depending on the triazole, with a decrease in the expression of CYP51, STAR, CYP11A1, CYP19A1, or HSD3B proteins, or a combination thereof, in hGCs and KGN cells and an increase in AHR in KGN cells.

Anti-androgenic activity of novel flame retardants in mixtures: Newly identified contribution from tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO)

In recent decades, male infertility has been on the rise, largely attributed to exposure to chemicals with endocrine-disrupting properties. The adverse effects of disrupting androgen actions on the development and reproductive health of children and adolescents have been extensively studied. Flame retardants (FRs), used in consumer products to delay flammability, have been identified as antagonists of the androgen receptor (AR), potentially leading to adverse outcomes in male reproductive health later in life. This study examined the interaction of eight novel FRs with the AR, employing an in vitro AR-dependent luciferase reporter gene assay utilizing MDA-kb2 cells. The investigation revealed the anti-androgenic activity of tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), a frequently detected FR in the environment. Furthermore, TDBP-TAZTO contributed to anti-androgenic activity when combined with six other anti-androgenic FRs. The mixture effects were predicted by three commonly employed models: concentration addition (CA), generalized CA, and independent action, with the CA model showcasing the highest accuracy. This suggests that all FRs act through a similar mechanism, as further confirmed by in silico molecular docking, indicating limited synergy or antagonism. Importantly, in the mixtures, each FR contributed to the induction of anti-androgenic effects at concentrations below their individual effective concentrations in single exposures. This raises concern for public health, especially considering the co-detection of these FRs and their potential co-occurrence with other anti-androgenic chemicals like bisphenols. Therefore, our findings, along with previous research, strongly support the incorporation of combined effects of mixtures in risk assessment to efficiently safeguard population health.

Exposure to phenols, chlorophenol pesticides, phthalate and PAHs and mortality risk: A prospective study based on 6 rounds of NHANES

OBJECTIVES

Human exposure to various endocrine disrupting chemicals (EDCs) is widespread and long-lasting. The primary objective of this study was to prospectively evaluate the association of combined exposure of phenols, chlorophenol pesticides, phthalate and polycyclic aromatic hydrocarbons (PAHs) and mortality risk in a representative US population.

METHODS

The data on urinary levels of phenols, chlorophenol pesticides, phthalates, and PAH metabolites, were collected from participants aged ≥20 years in six rounds of the National Health and Nutrition Examination Survey (NHANES) (2003-2014). NHANES-linked death records up to December 31, 2015 were used to ascertain mortality status and cause of death. Cox proportional hazards and competing risk models were mainly used for chemical and mortality risk association analysis. The weighted quantile sum (WQS) regression and the least absolute shrinkage and selection operator regression were employed to estimate the association between EDC co-exposure and mortality risk.

RESULTS

High levels of mono-n-butyl phthalate, monobenzyl phthalate, and 1-napthol were significantly associated with increased risk of all cause, cardiovascular disease (CVD) and cancer mortality among all participants. WQS index was associated with the risks of all-cause (hazard ratio [HR] = 1.389, 95%CI: 1.155-1.669) and CVD mortality (HR = 1.925, 95%CI: 1.152-3.216). High co-exposure scores were associated with elevated all-cause (HR = 2.842, 95% CI: 1.2.094-3.858), CVD (HR = 1.855, 95% CI: 1.525-2.255), and cancer mortality risks (HR = 2.961, 95% CI: 1.468-5.972). The results of subgroup analysis, competing risk model, and sensitivity analysis were generally consistent with the findings from the main analyses, indicating the robustness of our findings.

CONCLUSIONS

This study provided the first epidemiological evidence that co-exposure to EDC at fairly low levels contributed to elevated mortality risk among US adults. The underlying mechanisms for the effects of EDC co-exposure on human health are worthy of future exploration.

Joint effects of phenol, chlorophenol pesticide, phthalate, and polycyclic aromatic hydrocarbon on bone mineral density: comparison of four statistical models

Exposure to phenols, phthalates, pesticides, and polycyclic aromatic hydrocarbons (PAHs) can harm the skeleton. However, data about the joint effects of these chemicals' mixture on bone health are limited. The final analysis involved 6766 participants aged over 20 years recruited from the National Health and Nutrition Examination Survey. Generalized linear regression, weighted quantile sum (WQS) regression, Bayesian kernel machine regression (BKMR), and quantile g-computation (qgcomp) were performed to investigate the association of the urinary levels of chemicals (three phenols, two chlorophenol pesticides, nine phthalates, and six polycyclic aromatic hydrocarbon [PAH] metabolites) with bone mineral density (BMD) measurements and osteoporosis (OP) risk. Generalized linear regression identified that benzophenone-3, 2,4-dichlorophenol, mono-n-butyl phthalate, 1-napthol, 3-fluorene, 2-fluorene, and 1-phenanthrene were significantly associated with lower BMD and increased OP risk. The WQS index was negatively associated with total femur, femoral neck, and lumbar spine vertebra 1 (L1) BMD among all the participants, with corresponding β (95% confidence interval) values of -0.028 g/cm2 (-0.040, -0.017), -0.015 g/cm2 (-0.025, -0.004), and -0.018 g/cm2 (-0.033, -0.003). In the BKMR analysis, the overall effect of the mixture was significantly associated with femoral neck BMD among males and OP risk among females. The qgcomp model found a significant association between co-exposure and L1 BMD among all the participants and among males. Our study presents compelling epidemiological evidence that co-exposure to phenols, chlorophenol pesticides, phthalates, and PAHs is associated with reduced BMD and elevated OP risk. It provides epidemiologic evidence for the detrimental effects of these chemicals on bone health.

Mammary Gland Development in Male Rats Perinatally Exposed to Propiconazole, Glyphosate, or their Mixture

This study aimed to assess whether perinatal exposure to propiconazole (PRO), glyphosate (GLY) or their mixture (PROGLY) alters key endocrine pathways and the development of the male rat mammary gland. To this end, pregnant rats were orally exposed to vehicle, PRO, GLY, or a mixture of PRO and GLY from gestation day 9 until weaning. Male offspring were euthanized on postnatal day (PND) 21 and PND60. On PND21, GLY-exposed rats showed reduced mammary epithelial cell proliferation, whereas PRO-exposed ones showed increased ductal p-Erk1/2 expression without histomorphological alterations. On PND60, GLY-exposed rats showed reduced mammary gland area and estrogen receptor alpha expression and increased aromatase expression, whereas PRO-exposed ones showed enhanced lobuloalveolar development and increased lobular hyperplasia. However, PROGLY did not modify any of the endpoints evaluated. In summary, PRO and GLY modified the expression of key molecules and the development of the male mammary gland individually but not together.

Association between Serum Per- and Polyfluoroalkyl Substance Levels and Risk of Central and Peripheral Precocious Puberty in Girls

Concerns about the endocrine-disrupting effects of per- and polyfluoroalkyl substances (PFASs) have raised questions about their potential influence on precocious puberty in girls, which is an emerging concern in some populations. However, epidemiological evidence is lacking. In this study, 882 serum samples were collected from girls with central precocious puberty (CPP, n = 226), peripheral precocious puberty (PPP, n = 316), and healthy controls (n = 340) in 2021 in Shanghai, China. The serum levels of 25 legacy and emerging PFASs and 17 steroids were measured. Results showed that PFAS exposure was positively associated with estradiol levels. Eleven PFASs were significantly or marginally associated with the higher odds of the overall precocious puberty. Across subtypes, PFASs were more clearly associated with PPP, while the associations with CPP were consistent in direction but did not reach statistical significance. These findings were consistent with the assessment of PFAS mixtures using quantile-based g-computation (qgcomp) and Bayesian kernel machine regression, with perfluorobutane sulfonate and 6:2 polyfluorinated ether sulfonate showing the highest contribution to joint effects. Although changes in serum estradiol could arise from various factors, our results suggest that the PFAS exposure may contribute to the increase in estradiol secretion, thereby increasing the risk of precocious puberty, especially PPP. The potential effects of PFASs on precocious puberty warrant further investigation, given the associated complications of public health concern, including psychological distress and increased risk of multiple diseases.

Exposure to non-persistent pesticides and sexual maturation of Spanish adolescent males

BACKGROUND

Several non-persistent pesticides are endocrine disrupting chemicals and may impact on sexual maturation.

OBJECTIVE

To examine the association between urinary biomarkers of non-persistent pesticides and sexual maturation in adolescent males in the Environment and Childhood (INMA) Project.

METHODS

The metabolites of several pesticides were measured in spot urine samples collected from 201 boys aged 14-17 years, including: 3,5,6-trichloro-2-pyridinol (TCPy), metabolite of chlorpyrifos; 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPy), metabolite of diazinon; malathion diacid (MDA), metabolite of malathion; diethyl thiophosphate (DETP) and diethyl dithiophosphate, non-specific metabolites of organophosphates; 3-phenoxybenzoic acid (3-PBA) and dimethyl cyclopropane carboxylic acid, metabolites of pyrethroids; 1-naphthol (1-NPL), metabolite of carbaryl; and ethylene thiourea (ETU), metabolite of dithiocarbamate fungicides. Sexual maturation was assessed using Tanner stages, self-reported Pubertal Development Scale, and testicular volume (TV). Multivariate logistic regression was employed to examine associations between urinary pesticide metabolites and the odds of being in Tanner stage 5 of genital development (G5) or pubic hair growth (PH5); stage ≥4 of overall pubertal development, gonadarche, and adrenarche; or having mature TV (≥25 mL).

RESULTS

DETP concentrations>75th percentile (P75) were associated with lower odds of being in stage G5 (OR = 0.27; 95% CI = 0.10-0.70), detectable TCPy with lower odds of gonadal stage≥4 (OR = 0.50; 95% CI = 0.26-0.96), and intermediate detectable MDA concentrations (<P75) with lower odds of adrenal stage≥4 (OR = 0.32; 95% CI = 0.11-0.94). Conversely, detectable concentrations of 1-NPL were associated with higher odds of adrenal stage≥4 (OR = 2.61; 95% CI = 1.30-5.24) but lower odds of mature TV (OR = 0.42; 95% CI = 0.19-0.90).

CONCLUSION

Exposure to certain pesticides may be associated with delayed sexual maturity in adolescent males.

Azole pesticide products and their hepatic metabolites cause endocrine disrupting potential by suppressing the homo-dimerization of human estrogen receptor alpha

We selected azole pesticides products that are managed by setting maximum residue limits (MRLs) in the Republic of Korea and describe the estrogen receptor (ER) α-related negative effect to endocrine system using in vitro Organization for Economic Cooperation and Development performance-based test guideline. No azoles were found to be an ERα agonist. Conversely, three azoles (bitertanol, cafenstrole, and tebufenpyrad) were determined to be ERα antagonists. In addition, the ERα antagonistic activities of bitertanol, cafenstrole, and tebufenpyrad were not significantly perturbed in the existence of phase I (hydroxylation, dealkylation, oxidation or reduction) and phase II (conjugation). Regarding the mechanism underlying their ERα-mediated endocrine disrupting potentials, ERα proteins cannot be translocated to the nucleus by suppressing the dimerization of ERα in the cytoplasm by bitertanol, cafenstrole, and tebufenpyrad. These data indicated that azole pesticide products show the capability to interfere the ERα-related human endocrine system. Furthermore, we identified the mechanism of ERα-mediated endocrine disrupting by azole insecticide products through this study.

Triazole pesticides exposure impaired steroidogenesis associated to an increase in AHR and CAR expression in testis and altered sperm parameters in chicken

Since several decades, we observe the decline of various bird populations that could be partly linked to the agricultural intensification and the use of large amount of pesticides. Even if triazoles compounds are the most widely used fungicides, their effects on the reproductive parameters in birds are not clearly known. In the present study, we investigated the in vitro effects of 8 triazoles compounds alone (propiconazole (PP, from 0 to 10 µM), prothioconazole (PT), epoxiconazole (Epox), tetraconazole (TT), tebuconazole (TB), difenoconazole (Dif), cyproconazole (Cypro), metconazole (MC) (from 0 to 1 mM)) on the male chicken reproductive functions by using testis explants, primary Sertoli cells and sperm samples. In testis, all triazoles at the higher concentrations for 48 h inhibited lactate and testosterone secretion mostly in association with reduced expression of HSD3B and/or STAR mRNA levels. These data were also associated with increased expression of the nuclear receptors Aryl Hydrocarbon Receptor (AHR) and Constitutive Androstane Receptor (CAR) mRNA levels in testis and for all triazoles except for PP a reduction in Sertoli cell viability. When focusing on the sperm parameters, we demonstrated that most of the triazoles (MC, Epox, Dif, TB, TT and Cypro) at 0.1 or 1 mM for either 2, 12 or 24 min of exposure decreased sperm motility and velocity and increased the percentage of spermatozoa abnormal morphology. At the opposite, PP increased sperm motility in a dose dependent manner after 2 min of exposure whereas no significant effect was observed in response to PT whatever the dose and the time of exposure. Moreover, these effects were associated with an increase in the production of reactive oxygen species in spermatozoa. Taken together, most of the triazoles compounds impair testis steroidogenesis and semen parameters potentially through an increase in AHR and CAR expression and in oxidative stress, respectively.

Data Availability Statement

All the data will be available.

The effect of conazoles on reproductive organs structure and function – a review

Conazoles are azole antifungals used in agricultural and pharmaceutical products. Exposure to conazole fungicides leads to several toxic endpoints, including reproductive and endocrine. The results of animal experiments have shown that various conazole fungicides at high doses affect the structure and functions of reproductive organs. In males, adverse effects of conazole fungicides are manifested in the testes, prostate, sperm viability, fertility and sexual behaviour. Reduced testis weight, testis atrophy and reduced or absent sperm production were frequently observed. In female genitalia, structural changes in the ovaries and uterus have been observed. The extent of the changes depends on the dose and duration of treatment. Triazoles affected the expression of multiple genes involved in steroid hormone metabolism and modulate enzyme activity of multiple cytochrome P450 (CYP) and other metabolic enzymes in mammalian liver and other tissues. Conazole fungicides act as endocrine disruptors. Conazoles have been reported to reduce oestradiol and testosterone production and to increase progesterone concentration, indicating the inhibition of enzymes involved in the conversion of progesterone to testosterone. The reproductive effects are consistent with impairment of testosterone homeostasis. The disruption in steroid homeostasis is a common mode of action, leading to abnormal reproductive development and diminished reproductive function. At high doses, azole fungicides affect reproductive organs and fertility in several species.

Childhood exposure to non-persistent pesticides and pubertal development in Spanish girls and boys: Evidence from the INMA (Environment and Childhood) cohort

This study assessed cross-sectional associations between urinary metabolites of non-persistent pesticides and pubertal development in boys and girls from urban and rural areas in Spain and examined effect modification by body mass index (BMI). Four metabolites of insecticides (TCPy, metabolite of chlorpyrifos; IMPy, metabolite of diazinon; DETP, non-specific metabolite of organophosphates; 3-PBA, metabolite of pyrethroids) and the metabolite of ethylene-bis-dithiocarbamate fungicides (ETU) were quantified in urine collected in 2010-2016 from 7 to 11-year-old children (606 girls, 933 boys) participating in the INMA Project. Pubertal development was ascertained by Tanner stages and/or parent-reported Pubertal Development Scale (PDS). Associations between pesticide metabolites and odds of being in stage 2+ for breast development (girls), genital development (boys), pubic hair growth (girls and boys), and/or overall puberty onset, gonadarche, and adrenarche (PDS for girls and boys) were examined by mixed-effect logistic regression. Effect modification by BMI was explored by interaction terms and stratified analysis. In girls, DETP and ETU concentrations>75th percentile (P75) were associated with higher odds of overall puberty development (OR [95%CI] = 1.86 [1.07-3.24] and 1.71 [1.03-2.83], respectively, for > P75 vs. undetected concentrations), while ETU > P75 was also associated with higher odds of breast development (OR [95%CI] = 5.55 [2.83-12.91]), particularly in girls with underweight/normal weight (OR [95%CI] = 10.08 [2.62-38.76]). In boys, detection of TCPy (40%) and 3-PBA (34%) was associated with higher odds of genital development (OR [95%CI] = 1.97 [1.08-3.57] and 2.08 [1.15-3.81], respectively), and the association with 3-PBA was observed in boys with overweight/obesity alone. In addition, ETU > P75 was associated with higher odds of genital development in boys with underweight/normal weight (OR [95%CI] = 2.89 [1.08-7.74]) but higher DETP with lower odds of puberty in boys with overweight/obesity (OR [95%CI] = 0.94 [0.89-0.99] per log-unit increase in concentration). Results suggest an association of childhood exposure to ETU and certain insecticides with earlier puberty in girls and boys that may be modified by child BMI.

Non-additive mixture effects of benzo[a]pyrene and pesticides in vitro and in vivo: Role of AhR signaling

Polycyclic aromatic hydrocarbons (PAHs) and pesticides are two major groups of environmental contaminants which humans are simultaneously exposed to. However, potential mixture interactions of these groups of chemicals are not well-studied. In this study, the effects of binary mixtures of the PAH benzo[a]pyrene (B[a]P) and the commonly used pesticides chlorpyrifos, paraquat and tebuconazole on human liver HepG2 cells were investigated. The results showed that binary mixtures of B[a]P and paraquat or tebuconazole mainly caused additive effects on cell viability and cytochrome P4501a1 (CYP1A1) expression compared to single compound exposures. In contrast, the binary mixture with chlorpyrifos interacted antagonistically on cell viability and ROS production, whereas synergistic effects were observed for induction of CYP1A1 expression. B[a]P and chlorpyrifos also inhibited the activity of recombinant human CYP1A1 enzyme. To verify the synergistic in vitro results, zebrafish (Danio rerio) embryos were exposed to binary mixtures of B[a]P and chlorpyrifos. The mixtures caused synergistic induction of CYP1A expression, as well as synergistic developmental toxicity on multiple endpoints including non-inflated swim bladder, yolk-sac and pericardial edema, and spinal deformation. The effects were reduced upon morpholino-mediated knockdown of the aryl hydrocarbon receptor (AhR), indicating an AhR-dependence of the synergistic toxicity. Altogether, these data suggest that the combination of AhR activation and CYP1A1 inhibition is responsible for the underlying non-additive interaction between B[a]P and chlorpyrifos in vitro and in vivo.

Inhibition of Oocyte Maturation by Malathion and Structurally Related Chemicals in Zebrafish (Danio rerio) After In Vitro and In Vivo Exposure

Oogenesis is the process by which a primary oocyte develops into a fertilizable oocyte, making it critical to successful reproduction in fish. In zebrafish (Danio rerio), there are five stages of oogenesis. During the final step (oocyte maturation), the maturation-inducing hormone 17α,20β-dihydroxy-4-pregnen-3-one (MIH) activates the membrane progestin receptor, inducing germinal vesicle breakdown. Using in vitro assays, it has been shown that anthropogenic stressors can dysregulate MIH-induced oocyte maturation. However, it is unknown whether the in vitro assay is predictive of reproductive performance after in vivo exposure. We demonstrate that a known inhibitor of oocyte maturation, malathion, and a structurally related chemical, dimethoate, inhibit oocyte maturation. However, malaoxon and omethoate, which are metabolites of malathion and dimethoate, did not inhibit oocyte maturation. Malathion and dimethoate inhibited maturation to a similar magnitude when oocytes were exposed for 4 h in vitro or 10 days in vivo, suggesting that the in vitro zebrafish oocyte maturation assay might be predictive of alterations to reproductive performance. However, when adult zebrafish were exposed to malathion for 21 days, there was no alteration in fecundity or fertility in comparison with control fish. Our study supports the oocyte maturation assay as being predictive of the success of in vitro oocyte maturation after in vivo exposure, but it remains unclear whether inhibition of MIH-induced oocyte maturation in vitro correlates to decreases in reproductive performance. Environ Toxicol Chem 2022;41:1381-1389. © 2022 SETAC.

Magnetic solid-phase extraction based on zirconium-based metal-organic frameworks for simultaneous enantiomeric determination of eight chiral pesticides in water and fruit juices

A novel multi-residue method, magnetic solid-phase extraction combined with LC-MS/MS, was proposed for simultaneous enantiomeric determination of eight chiral pesticides in water and fruit juices. Fe₃O₄@C@UiO-66 was firstly used to extract and enrich pesticides, showing excellent adsorption capacity, which was proved by adsorption kinetic and thermodynamic experiments. Multiple extraction parameters were optimized by Plackett-Burman and Box-Behnken design. Under optimized conditions, good linearity (1.0-200 ng L^-1, R² ≥ 0.9953) for all analytes, detection limits (0.10 to 0.35 ng L^-1), quantitation limits (0.35 to 1.00 ng L^-1), recoveries (83.68-95.99%), and precision (intra-day RSD ≤ 7.06%, inter-day RSD ≤ 9.40%) were obtained, meeting the requirements of pesticides residues analysis. It is worth mentioning that eight chiral pesticides can be separated quickly within 19 min. The above results indicate that the proposed method with satisfactory sensitivity and accuracy has the potential for routine analysis of chiral pesticide residues in aqueous samples.

Ginger reserves testicular spermatogenesis and steroidogenesis in difenoconazole-intoxicated rats by conducting oxidative stress, apoptosis and proliferation

Difenoconazole, a triazole fungicide, can induce reproductive toxicity in aquatic species, but the probable mechanisms of this hazard in mammals are not formally reported. Here, we have examined the possible ameliorative efficiency of the ginger aqueous extract against the reproductive toxicity of difenoconazole in male rats. Thirty-six animals were equally divided into six groups: control, ginger aqueous extract (50 mg/kg), difenoconazole (15 mg/kg), difenoconazole (30 mg/kg) and ginger co-treated with two doses of difenoconazole. Difenoconazole markedly decreased sperm count, motility and normality percentage, together with the Johnson score. Difenoconazole also significantly reduced serum testosterone, luteinizing hormone and follicle-stimulating hormone levels, as well as the activities of testicular steroidogenic acute regulatory protein and 17 β-hydroxysteroid dehydrogenases. Furthermore, difenoconazole brought a significant decrease in the testicular activity of catalase, but it increased the activity of glutathione peroxidase. Moreover, difenoconazole upregulated the testicular transcripts of Bax and caspase-3, increased Ki-67 immunoreactivity and induced histoarchitecture alterations plus DNA damage. Remarkably, ginger co-treatment preserved sperm toxicity, restored hormone profiles, increased steroidogenic activity and prevented oxidative injury-promoted testicular apoptosis. In conclusion, phenolic acids and flavonoids of ginger can reserve spermatogenesis and steroidogenesis in difenoconazole-intoxicated rats by improving testicular redox status, inhibiting apoptosis and refining proliferation capacity.

Sex Reversal and Performance in Fitness-Related Traits During Early Life in Agile Frogs

Sex reversal is a mismatch between genetic sex (sex chromosomes) and phenotypic sex (reproductive organs and secondary sexual traits). It can be induced in various ectothermic vertebrates by environmental perturbations, such as extreme temperatures or chemical pollution, experienced during embryonic or larval development. Theoretical studies and recent empirical evidence suggest that sex reversal may be widespread in nature and may impact individual fitness and population dynamics. So far, however, little is known about the performance of sex-reversed individuals in fitness-related traits compared to conspecifics whose phenotypic sex is concordant with their genetic sex. Using a novel molecular marker set for diagnosing genetic sex in agile frogs (Rana dalmatina), we investigated fitness-related traits in larvae and juveniles that underwent spontaneous female-to-male sex reversal in the laboratory. We found only a few differences in early life growth, development, and larval behavior between sex-reversed and sex-concordant individuals, and altogether these differences did not clearly support either higher or lower fitness prospects for sex-reversed individuals. Putting these results together with earlier findings suggesting that sex reversal triggered by heat stress may be associated with low fitness in agile frogs, we propose the hypothesis that the fitness consequences of sex reversal may depend on its etiology.

Impairment of caprine oocyte maturation in vitro and alteration of granulosa cells functions by widely used fungicide mancozeb

Mancozeb is classified as an endocrine disruptor; thus the present study was carried out to investigate the impact of mancozeb on mammalian ovarian functions using in vitro caprine oocyte maturation and granulosa cell culture models. Caprine cumulus oocyte complexes (COCs) and granulosa cells were cultured under standard culture conditions and treated with mancozeb concentrations of 0.3, 3, and 30 μg/ml along with a control for 24 h and assessed. Granulosa cell viability and progesterone concentration in spent culture media after treatments were also assessed. Mancozeb significantly decreased (P < 0.05) the oocytes cumulus expansion and the maturation of caprine oocytes. Marked changes in granulose cell morphology were observed with 30 μg/ml mancozeb and significantly reduced (P < 0.05) cell viability. Interestingly, the same concentrations significantly increased (P < 0.05) the progesterone secretion by the cells. Significant reduction of granulosa cells viability and reduction of cumulus expansion and suppression of metaphase plate formation in oocyte can impair the fertilization ability and developmental potential of the oocytes. High progesterone concentration due to mancozeb treatment may suppress LH surge and suppress ovulation. In conclusion, mancozeb suppresses granulosa cells viability, reduces cumulus expansion, and suppresses metaphase plate formation but induces progesterone secretion from granulosa cells that may inhibit LH surge for ovulation process.

Predicting the Activation of the Androgen Receptor by Mixtures of Ligands Using Generalized Concentration Addition

Concentration/dose addition is widely used for compounds that act by similar mechanisms. But it cannot make predictions for mixtures of full and partial agonists for effect levels above that of the least efficacious component. As partial agonists are common, we developed generalized concentration addition, which has been successfully applied to systems in which ligands compete for a single binding site. Here, we applied a pharmacodynamic model for a homodimer receptor system with 2 binding sites, the androgen receptor, that acts according to the classic homodimer activation model: Each cytoplasmic monomer protein binds ligand, undergoes a conformational change that relieves inhibition of dimerization, and binds to DNA response elements as a dimer. We generated individual dose-response data for full (dihydroxytestosterone, BMS564929) and partial (TFM-4AS-1) agonists and a competitive antagonist (MDV3100) using reporter data generated in the MDA-kb2 cell line. We used the Schild method to estimate the binding affinity of MDV3100. Data for individual compounds fit the homodimer pharmacodynamic model well. In the presence of a full agonist, the partial agonist had agonistic effects at low effect levels and antagonistic effects at high levels, as predicted by pharmacological theory. The generalized concentration addition model fits the empirical mixtures data-full/full agonist, full/partial agonist, and full agonist/antagonist-as well or better than relative potency factors or effect summation. The ability of generalized concentration addition to predict the activity of mixtures of different types of androgen receptor ligands is important as a number of environmental compounds act as partial androgen receptor agonists or antagonists.

Evaluation of Gonadal Alterations in a Population Environmentally Exposed to a Mixture of Endocrine Active Pesticides

Although there are studies that show that some pesticides produce gonadal dysfunction and gonadal cancer in different animals, there are not many studiesregardinghumans. This study determined the prevalence and risk in humans of developing ovarian or testicular dysfunction or cancer in areas with distinct exposure to pesticides, which have endocrine disrupting properties. A population-based case-control study was carried out on humans living in ten health districts of Andalusia (Southern Spain) classified as areas of high or low environmental exposure to pesticides according to agronomic criteria. The study population included 5332 cases and 13,606 controls. Data were collected from computerized hospital records between 2000 and 2018.The risk of gonadal dysfunction or cancer was significantly higher in areas with higher use of pesticides in relation to those with lower use.

Developmental reproductive toxicity and endocrine activity of propiconazole in the Xenopus tropicalis model

Environmental pollutants and especially endocrine disrupting chemicals (EDCs) are implicated as one of the drivers of the amphibian declines. To advance the understanding of the risks of EDCs to amphibians, methods to determine endocrine-linked adverse effects are needed. The aims were to 1) develop a partial life-cycle assay with the model frog Xenopus tropicalis to determine endocrine perturbation and adverse developmental effects, and 2) determine effects of propiconazole in this assay. Propiconazole is a pesticide with multiple endocrine modes of action in vitro. Its potential endocrine activity and adverse effects in amphibians remain to be elucidated. Tadpoles were exposed to 0, 33 and 384 μg propiconazole/L during critical developmental windows until completed metamorphosis. At metamorphosis, a sub-sample of animals was analysed for endpoints for disruption of estrogen/androgen (sex ratio, brain aromatase activity) and thyroid pathways (time to metamorphosis). The remaining individuals were kept unexposed for 2 months post-metamorphosis to analyze effects on sexual development including gonadal and Müllerian duct maturity and gametogenesis. At metamorphosis, brain aromatase activity was significantly increased in the high-dose group compared to control. In both propiconazole groups, an increased proportion of individuals reached metamorphosis faster than the mean time for controls, suggesting a stimulatory effect on the thyroid system. At 2 months post-metamorphosis, testis size, sperm and Müllerian duct maturity were reduced in the low-dose males, and the liver somatic index in males was increased in both propiconazole groups, compared with controls. In conclusion, our results show that propiconazole exposure caused endocrine perturbations and subsequent hepatic and reproductive effects evident at puberty, indicating persistent disruption of metabolism and male reproductive function. Our findings advance the development of methodology to determine endocrine and adverse effects of EDCs. Moreover, they increase the understanding of endocrine perturbations and consequent risk of adverse effects of azoles in amphibians.

The fungicide Mancozeb reduces spheroid attachment onto endometrial epithelial cells through downregulation of estrogen receptor β and integrin β3 in Ishikawa cells

Mancozeb is a metal-containing ethylene bis-dithiocarbamate fungicide widely used in agriculture. Ethylene thiourea (ETU) is the primary metabolite of Mancozeb. Mancozeb has been associated with spontaneous abortions and abnormal menstruation in women. However, the effects of Mancozeb and ETU on embryo attachment remain unknown. The human blastocyst surrogate trophoblastic spheroids (JEG-3), endometrial epithelial surrogate adenocarcinoma cells (Ishikawa), or human primary endometrial epithelial cells (EECs) monolayer were used in the spheroid attachment models. Ishikawa and EECs were pretreated with different concentrations of Mancozeb or ETU for 48 h before the attachment assay. Gene expression profiles of Ishikawa cells were examined to understand how Mancozeb modulates endometrial receptivity with Microarray. The genes altered by Mancozeb were confirmed by qPCR and compared with the ETU treated groups. Mancozeb and ETU treatment inhibited cell viability at 10 μg/mL and 5000 µg/mL, respectively. At non-cytotoxic concentrations, Mancozeb at 3 μg/mL and ETU at 300 μg/mL reduced JEG-3 spheroid attachment onto Ishikawa cells. A similar result was observed with human primary endometrial epithelial cells. Mancozeb at 3 μg/mL modified the transcription of 158 genes by at least 1.5-fold in Microarray analysis. The expression of 10 differentially expressed genes were confirmed by qPCR. Furthermore, Mancozeb decreased spheroid attachment possibly through downregulating the expression of endometrial estrogen receptor β and integrin β3, but not mucin 1. These results were confirmed in both overexpression and knockdown experiments and co-culture assay. Mancozeb but not its metabolite ETU reduced spheroid attachment through modulating gene expression profile and decreasing estrogen receptor β and integrin β3 expression of endometrial epithelial cells.

Bioassay guided analysis coupled with non-target chemical screening in polyethylene plastic shopping bag fragments after exposure to simulated gastric juice of Fish

In this study, fragments of polyethylene plastic bags were treated with simulated gastric juice of fish for 16 h. Following solid-phase extraction, methanol eluents caused acute toxicity to embryos and larvae of Japanese medaka. Chromatographic fractions (polar to more non-polar with numbers increasing) of the extract were evaluated for toxicity and estrogenic activity using medaka and an estrogen receptor (ER) cell-line. Fractions 6 and 9 had the highest estrogenic effects with relative hydrophobic chemicals. The vtg expression in fraction 6 was 22-fold higher than control, and the ER cellular response in fraction 9 was 8.5-fold higher than controls. Following non-target screening (NTS), several novel phthalates and phenols were identified in the above two fractions. Fractions 1 and 2 appeared to be primarily responsible for the acute toxicity observed with the whole extract. The hatching rate decreased to 36 % in fraction 2, and was not observed following exposure to fraction 1. NTS of these fractions indicated 635 and 808 entities, respectively, most without toxicity information. These results indicate plastic leachates from gastric juices of fish are complex mixtures of many compounds that can have acute reproductive and sublethal endocrine impacts in fish.

Ten years of research on synergisms and antagonisms in chemical mixtures: A systematic review and quantitative reappraisal of mixture studies

BACKGROUND

Several reviews of synergisms and antagonisms in chemical mixtures have concluded that synergisms are relatively rare. However, these reviews focused on mixtures composed of specific groups of chemicals, such as pesticides or metals and on toxicity endpoints mostly relevant to ecotoxicology. Doubts remain whether these findings can be generalised. A systematic review not restricted to specific chemical mixtures and including mammalian and human toxicity endpoints is missing.

OBJECTIVES

We conducted a systematic review and quantitative reappraisal of 10 years' of experimental mixture studies to investigate the frequency and reliability of evaluations of mixture effects as synergistic or antagonistic. Unlike previous reviews, we did not limit our efforts to certain groups of chemicals or specific toxicity outcomes and covered mixture studies relevant to ecotoxicology and human/mammalian toxicology published between 2007 and 2017.

DATA SOURCES, ELIGIBILITY CRITERIA

We undertook searches for peer-reviewed articles in PubMed, Web of Science, Scopus, GreenFile, ScienceDirect and Toxline and included studies of controlled exposures of environmental chemical pollutants, defined as unintentional exposures leading to unintended effects. Studies with viruses, prions or therapeutic agents were excluded, as were records with missing details on chemicals' identities, toxicities, doses, or concentrations.

STUDY APPRAISAL AND SYNTHESIS METHODS

To examine the internal validity of studies we developed a risk-of-bias tool tailored to mixture toxicology. For a subset of 388 entries that claimed synergisms or antagonisms, we conducted a quantitative reappraisal of authors' evaluations by deriving ratios of predicted and observed effective mixture doses (concentrations).

RESULTS

Our searches produced an inventory of 1220 mixture experiments which we subjected to subgroup analyses. Approximately two thirds of studies did not incorporate more than 2 components. Most experiments relied on low-cost assays with readily quantifiable endpoints. Important toxicity outcomes of relevance for human risk assessment (e.g. carcinogenicity, genotoxicity, reproductive toxicity, immunotoxicity, neurotoxicity) were rarely addressed. The proportion of studies that declared additivity, synergism or antagonisms was approximately equal (one quarter each); the remaining quarter arrived at different evaluations. About half of the 1220 entries were rated as "definitely" or "probably" low risk of bias. Strikingly, relatively few claims of synergistic or antagonistic effects stood up to scrutiny in terms of deviations from expected additivity that exceed the boundaries of acceptable between-study variability. In most cases, the observed mixture doses were not more than two-fold higher or lower than the predicted additive doses. Twenty percent of the entries (N = 78) reported synergisms in excess of that degree of deviation. Our efforts of pinpointing specific factors that predispose to synergistic interactions confirmed previous concerns about the synergistic potential of combinations of triazine, azole and pyrethroid pesticides at environmentally relevant doses. New evidence of synergisms with endocrine disrupting chemicals and metal compounds such as chromium (VI) and nickel in combination with cadmium has emerged.

CONCLUSIONS, LIMITATIONS AND IMPLICATIONS

These specific cases of synergisms apart, our results confirm the utility of default application of the dose (concentration) addition concept for predictive assessments of simultaneous exposures to multiple chemicals. However, this strategy must be complemented by an awareness of the synergistic potential of specific classes of chemicals. Our conclusions only apply to the chemical space captured in published mixture studies which is biased towards relatively well-researched chemicals.

SYSTEMATIC REVIEW REGISTRATION NUMBER

The final protocol was published on the open-access repository Zenodo and attributed the following digital object identifier, doi: https://doi.org//10.5281/zenodo.1319759 (https://zenodo.org/record/1319759#.XXIzdy7dsqM).

Endocrine-disrupting activity of mancozeb

The objective of the present study was to review the existing data on the mechanisms involved in the endocrine disrupting activity of mancozeb (MCZ) in its main targets, including thyroid and gonads, as well as other endocrine tissues that may be potentially affected by MCZ. MCZ exposure was shown to interfere with thyroid functioning through impairment of thyroid hormone synthesis due to inhibition of sodium-iodine symporter (NIS) and thyroid peroxidase (TPO) activity, as well as thyroglobulin expression. Direct thyrotoxic effect may also contribute to thyroid pathology upon MCZ exposure. Gonadal effects of MCZ involve inhibition of sex steroid synthesis due to inhibition of P450scc (CYP11A1), as well as 3β-HSD and 17β-HSD. In parallel with altered hormone synthesis, MCZ was shown to down-regulate androgen and estrogen receptor signaling. Taken together, these gonad-specific effects result in development of both male and female reproductive dysfunction. In parallel with clearly estimated targets for MCZ endocrine disturbing activity, namely thyroid and gonads, other endocrine tissues may be also involved. Specifically, the fungicide was shown to affect cortisol synthesis that may be mediated by modulation of CYP11B1 activity. Moreover, MCZ exposure was shown to interfere with PPARγ signaling, being a key regulator of adipogenesis. The existing data also propose that endocrine-disrupting effects of MCZ exposure may be mediated by modulation of hypothalamus-pituitary-target axis. It is proposed that MCZ neurotoxicity may at least partially affect central mechanisms of endocrine system functioning. However, further studies are required to unravel the mechanisms of MCZ endocrine disrupting activity and overall toxicity.

Placental transfer of pesticides studied in human placental perfusion

To investigate the transplacental transport of pesticides, the pyrethroid cypermethrin and the fungicide azoles, propiconazole and bitertanol were tested in the placental perfusion model. Cypermethrin, propiconazole and bitertanol were also tested in the BeWo cell transfer model. The pesticides were chosen with the selection criteria: use in Denmark, significant treated areas and knowledge on hormone-disrupting effects. Propiconazole and bitertanol showed rapid transfer and adsorbance to the system in both placental perfusion and BeWo cell system, whereas cypermethrin had a slower transport across the placental cell layers in the two models. There was no difference between data of the single pesticides and their mixture in either placental perfusion or BeWo cell transfer model. Both the placental perfusion model and the BeWo cell model metabolized the pesticides and released metabolites into both foetal and maternal circulation. Using human exposure models, this study shows the potential exposure of the human foetus to pesticides cypermethrin, propiconazole and bitertanol and their metabolites.

Determination and ecological risk assessment of two endocrine disruptors from River Buffalo, South Africa

4-tert-Octylphenol (4-tOP) and triclosan (TCS) are endocrine disruptors which have been detected in environmental matrices such as air, soil and water at ultra-low levels. Exposure to endocrine disruptors may account at least in part, for the global increase in the incidence of non-communicable diseases like cancers and diabetes and may also lead to an imbalance in the aquatic ecosystem. River Buffalo is an important natural resource in the Eastern Cape of South Africa serving more than half a million people. The presence of the two compounds in the river water hitherto unknown was investigated during winter seasons using solid-phase extraction and gas chromatography-mass spectrometric techniques. The sampling points differed by some physicochemical parameters. The concentration of 4-tOP ranged 0-755 ng/L, median value 88.1 ng/L while that of TCS ranged 0-1264.2 ng/L and the median value was 82.1 ng/L. Hazard quotient as an index of exposure risk varied according to daphnids ˃ fish ˃ algae for 4-tOP exposure while HQ for TCS exposure was algae > daphnids = fish showing that both compounds were capable of causing imbalance in the aquatic ecosystem. Graphical abstract.

Exposure to organophosphorus insecticides and increased risks of health and cancer in US women

Results of this paper provide evidence that chronic long-term exposure to organophosphorus insecticides poses a significantly higher health risk for US women than for men, based on dialkylphosphate biomarker data from NHANES cycles 2003-2012. The risk of cardiovascular disease for female non-smokers aged 60-85 years in the highest dimethylthiophosphate (DMTP) urinary concentration quartile is 3.0 (odds ratio, OD = 3.0, 95%CI 1.4-6.4) times higher than that in the lowest quartile. Women with higher urinary DMTP concentrations also have significantly higher risk of asthma at the ages 6-39 years and an apparently higher risk of chronic bronchitis at the ages 60-85. Overall cancer risk is significantly higher for female non-smokers aged 60-85 years in the higher urinary DMTP quartiles (OD = 2.7, 95% CI 1.3-5.9). Increasing risks of breast cancer for female smokers and prostate cancer for male smokers aged 60-85 years with higher exposure to organophosphorus insecticides in the US are also significant.

Effect of wheat species (Triticum aestivum vs T. spelta), farming system (organic vs conventional) and flour type (wholegrain vs white) on composition of wheat flour - Results of a retail survey in the UK and Germany - 3. Pesticide residue content

Wheat is a major component of the Northern European diet and contributes significantly to dietary pesticide exposure. Here we report results of a 2-year retail survey, which compared pesticide residues in organic and conventional, whole-grain and white, common and Spelt wheat flour brands available in the UK and Germany. Pesticide residues were detected significantly more frequently in conventional (87%) than organic (25%) flour samples. Chlormequat, a plant growth regulator, was the most frequently detected compound. Total concentrations of pesticide residues were (a) ~4 times higher in conventional than organic, (b) ~100% higher in common than Spelt wheat flour and (c) ~110% higher in conventional whole-grain than white flour samples, but (d) not significantly different in organic whole-grain and white flour. Results suggest that the use of organic wheat products allows increased whole-grain cereal consumption in line with nutritional recommendations, without an increase in dietary pesticide intake.

Agrochemicals and obesity

Obesity has become a very large concern worldwide, reaching pandemic proportions over the past several decades. Lifestyle factors, such as excess caloric intake and decreased physical activity, together with genetic predispositions, are well-known factors related to obesity. There is accumulating evidence suggesting that exposure to some environmental chemicals during critical windows of development may contribute to the rapid increase in the incidence of obesity. Agrochemicals are a class of chemicals extensively used in agriculture, which have been widely detected in human. There is now considerable evidence linking human exposure to agrochemicals with obesity. This review summarizes human epidemiological evidence and experimental animal studies supporting the association between agrochemical exposure and obesity and outlines possible mechanistic underpinnings for this link.

Organophosphate Pesticide Exposure and Breast Cancer Risk: A Rapid Review of Human, Animal, and Cell-Based Studies

BACKGROUND

Organophosphate pesticides (OPs) are one of the most commonly used classes of insecticides in the U.S., and metabolites of OPs have been detected in the urine of >75% of the U.S.

POPULATION

While studies have shown that OP exposure is associated with risk of neurological diseases and some cancers, the relationship between OP exposure and breast cancer risk is not well understood.

METHODS

The aim of this rapid review was to systematically evaluate published literature on the relationship between OP exposure and breast cancer risk, including both epidemiologic and laboratory studies. Twenty-seven full-text articles were reviewed by searching on Pubmed, EMBASE, and Cochrane databases.

RESULTS

Some human studies showed that malathion, terbufos, and chlorpyrifos were positively associated with human breast cancer risk, and some laboratory studies demonstrated that malathion and chlorpyrifos have estrogenic potential and other cancer-promoting properties. However, the human studies were limited in number, mostly included agricultural settings in several geographical areas in the U.S., and did not address cumulative exposure.

CONCLUSIONS

Given the mixed results found in both human and laboratory studies, more research is needed to further examine the relationship between OP exposure and breast cancer risk, especially in humans in non-agricultural settings.

Testosterone recuperates deteriorated male fertility in cypermethrin intoxicated rats

The present study investigates the protective effects of testosterone against reproductive toxicity induced by cypermethrin (50 mg/kg body weight) in rats. Significant reduction in the testicular and accessory sex organ weights were observed in cypermethrin-treated rats over controls. Cypermethrin intoxication significantly reduced testicular daily sperm count, epididymal sperm count, sperm motility, sperm viability and HOS-tail coiled sperm accompanied by significant reduction in the activity levels of testicular steroidogenic enzymes such as 3β- and 17β- hydroxysteroid dehydrogenases in rats as compared to controls. Further, qPCR studies indicated that the mRNA expression levels of steroidogenic acute regulatory protein (StAR) significantly decreased in cypermethrin-treated rats over controls. Molecular docking analysis indicated that the binding affinity of cypermethrin (- 11.2 kcal/mol) towards StAR protein was greater as compared to its natural ligand, cholesterol (- 8.2 kcal/mol) suggesting improper cholesterol channeling across the testis. Significant reduction in the circulatory levels of testosterone was also recorded in cypermethrin-exposed rats. An increase in pre- and post-implantation loss was observed in rats cohabited with cypermethrin-treated rats. On the other hand, testosterone (4.16 mg/kg body weight) treatment ameliorated cypermethrin-induced reprotoxic effects in rats. To conclude, cypermethrin-induced deterioration of suppressed reproductive performance in male rats could be linked to its antiandrogenic effects and on the other hand, testosterone-mediated protection of male reproductive health in cypermethrin-treated rats at least in part occurs via restoration of testosterone biosynthesis, spermatogenesis and sperm maturation events.

Organophosphate toxicity: updates of malathion potential toxic effects in mammals and potential treatments

Organophosphorus insecticides toxicity is still considered a major global health problem. Malathion is one of the most commonly used organophosphates nowadays, as being considered to possess relatively low toxicity compared with other organophosphates. However, widespread use may lead to excessive exposure from multiple sources. Mechanisms of MAL toxicity include inhibition of acetylcholinesterase enzyme, change of oxidants/antioxidants balance, DNA damage, and facilitation of apoptotic cell damage. Exposure to malathion has been associated with different toxicities that nearly affect every single organ in our bodies, with CNS toxicity being the most well documented. Malathion toxic effects on liver, kidney, testis, ovaries, lung, pancreas, and blood were also reported. Moreover, malathion was considered as a genotoxic and carcinogenic chemical compound. Evidence exists for adverse effects associated with prenatal and postnatal exposure in both animals and humans. This review summarizes the toxic data available about malathion in mammals and discusses new potential therapeutic modalities, with the aim to highlight the importance of increasing awareness about its potential risk and reevaluation of the allowed daily exposure level.

Impact of pesticide coexposure: an experimental study with binary mixtures of lambda-cyhalothrin (LCT) and captan and its impact on the toxicokinetics of LCT biomarkers of exposure

This study aimed at gaining more insights into the impact of pesticide coexposure on the toxicokinetics of biomarkers of exposure. This was done by conducting an in vivo experimental case-study with binary mixtures of lambda-cyhalothrin (LCT) and captan and by assessing its impact on the kinetic profiles of LCT biomarkers of exposure. Groups of male Sprague-Dawley rats were exposed orally by gavage to LCT alone (2.5 or 12.5 mg/kg bw) or to a binary mixture of LCT and captan (2.5/2.5 or 2.5/12.5 or 12.5/12.5 mg/kg bw). In order to establish the temporal profiles of the main metabolites of LCT, serial blood samples were taken, and excreta (urine and feces) were collected at predetermined intervals up to 48 h post-dosing. Major LCT metabolites were quantified in these matrices: 3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropane carboxylic (CFMP), 3-phenoxybenzoic acid (3-PBA), 4-hydroxy-3-phenoxybenzoic acid (4-OH3PBA). There was no clear effect of coexposure at the low LCT dose on the kinetics of CFMP and 3-PBA metabolites, based on the combined assessment of temporal profiles of these metabolites in plasma, urine and feces; however, plasma levels of 3-PBA were diminished in the coexposed high-dose groups. A significant effect of coexposure on the urinary excretion of 4-OH3PBA was also observed while fecal excretion was not affected. The temporal profiles of metabolites in plasma and in excreta were further influenced by the LCT dose. In addition, the study revealed kinetic differences between metabolites with a faster elimination of 3-PBA and 4-OH3BPA compared to CFMP. These results suggest that the pyrethroid metabolites CFMP and 3-PBA, mostly measured in biomonitoring studies, remain useful as biomarkers of exposure in mixtures, when pesticide exposure levels are below the reference values. However, the trend of coexposure effect observed in the benzyl metabolite pathway (in particular 4-OH3BPA) prompts further investigation.

Agrochemicals and neurogenesis

Agrochemicals or pesticides are compounds widely used to prevent, destroy or mitigate pests such as insects, rodents, herbs and weeds. However, most of them also act as environmental estrogens, anti-estrogens and/or antiandrogenic chemicals. In addition, both herbicides (such as glyphosate and paraquat) and insecticides (such as pyrethroids, organophosphates, neonicotinoids and rotenone) have been shown to exert significant adverse effects on hippocampal neurogenesis. These effects are particularly important because neurogenesis dysregulation could be associated with cognitive decline and neuropathologies such as Alzheimer's disease. This review focuses on the most commonly used agrochemicals in Argentina and their effects on the hippocampal neurogenesis of mammals. It also discusses the disruption of hormone synthesis and action as a possible mechanism through which these chemical compounds could alter the brain functions. Finally, we propose some lines of research to study the potential endocrine mechanisms involved in the effects of agrochemicals on human health and biodiversity.

Relationship between agrochemical compounds and mammary gland development and breast cancer

The exposure to agrochemical pesticides has been associated with several chronic diseases, including different types of cancer and reproductive disorders. In addition, because agrochemical pesticides may act as endocrine disrupting chemicals (EDCs) during different windows of susceptibility, they can increase the risk of impairing the normal development of the mammary gland and/or of developing mammary lesions. Therefore, the aim of this review is to summarize how exposure to different agrochemical pesticides suspected of being EDCs can interfere with the normal development of the mammary gland and the possible association with breast cancer. It has been shown that the mammary glands of male and female rats and mice are susceptible to exposure to non-organochlorine (vinclozolin, atrazine, glyphosate, chlorpyrifos) and organochlorine (endosulfan, methoxychlor, hexachlorobenzene) pesticides. Some of the effects of these compounds in experimental models include increased or decreased mammary development, impaired cell proliferation and steroid receptor expression and signaling, increased malignant cellular transformation and tumor development and angiogenesis. Contradictory findings have been found as to whether there is a causal link between the exposure or the pesticide body burden and breast cancer in humans. However, an association has been observed between pesticides (especially organochlorine compounds) and specific subtypes of breast cancer. Further studies are needed in both humans and experimental models to understand how agrochemical pesticides can induce or promote changes in the development, differentiation and/or malignant transformation of the mammary gland.

Integrated Approach to Evaluate the Association between Exposure to Pesticides and Idiopathic Premature Thelarche in Girls: The PEACH Project

Several pesticides are recognized as endocrine-disrupting chemicals (EDCs) since they can interfere with the dysregulation of sexual, thyroid and neuro-endocrine hormones. Children are particularly vulnerable to the adverse effects of EDCs due to their developmental stage, peculiar lifestyle and dietary habits. In this context, the exposure to pesticides represents an important risk factor associated with early development. This study deals with the possible association between exposure to pesticides and idiopathic premature thelarche in girls from areas of intensive agriculture practice in the Centre of Italy. An integrated approach was set up, including: (i) a case-control study on girls with idiopathic premature thelarche; (ii) the evaluation of multiple pesticides exposure in girls; (iii) the evaluation of multiple pesticides in food; (iv) the dietary intake of pesticide residues; (v) the assessment of toxicological effects of widely used pesticides by in vitro model. Data integration will provide an estimate of the predictive risk of potential effects on girls' health, linked to dietary intake.

Effects of two little-studied environmental pollutants on early development in anurans

Despite intensive ecotoxicological research, we still know relatively little about the ecological impacts of many environmental contaminants. Filling these knowledge gaps is particularly important regarding amphibians, because they play significant roles in freshwater and terrestrial ecosystems, and their populations are declining worldwide. In this study, we investigated two pollutants that have been poorly studied in ecotoxicology despite their widespread occurrence in surface waters: the herbicide terbuthylazine and the pharmaceutical drug carbamazepine. We exposed two anuran species throughout their larval development to each of two environmentally relevant concentrations of each pollutant, and recorded mortality and 17 sub-lethal endpoints up to several months after exposure. Mortality was low and unrelated to treatment. In agile frogs (Rana dalmatina), we found that treatment with 0.3 μg/L terbuthylazine decreased tadpole activity and reduced fat bodies in juveniles, whereas treatment with 50 μg/L carbamazepine decreased spleen size and increased spleen pigmentation. In common toads (Bufo bufo), treatment with 0.003 μg/L terbuthylazine increased body mass at metamorphosis, treatment with 0.3 μg/L terbuthylazine increased the size of optic tecta, and treatment with 0.5 μg/L carbamazepine decreased hypothalamus size. Treatment with 50 μg/L carbamazepine reduced the feeding activity of toad tadpoles, decreased their production of anti-predatory bufadienolide toxins, and increased their body mass at metamorphosis; juvenile toads in this treatment group had reduced spleen pigmentation. Neither treatments affected the time to metamorphosis, post-metamorphic body mass, or sex ratios significantly. These results show that environmental levels of both terbuthylazine and carbamazepine can have several sub-lethal effects on anurans, which may be detrimental to individual fitness and population persistence in natural conditions. Our findings further highlight that toxic effects cannot be generalized between chemicals of similar structure, because the terbuthylazine effects we found do not conform with previously reported effects of atrazine, a related and extensively studied herbicide.

Disruption of 17β-estradiol secretion by persistent organic pollutants present in human follicular fluid is dependent on the potential of ovarian granulosa tumor cell lines to metabolize estrogen

Endocrine-disrupting chemicals (EDCs), such as perfluorooctanoate, perfluorooctane sulfonate, 2,2-dichlorodiphenyldichloroethylene, hexachlorobenzene, and polychlorinated biphenyl 153 are persistent pollutants that are found in human follicular fluid (FF). These compounds may affect endocrine function, disrupt steroid secretion by granulosa cells, and play a role in granulosa cell tumor (GCT) development. GCTs demonstrate endocrine activity, expressing aromatase and secreting 17β-estradiol (E2). We aimed to determine the effects of a mixture of EDCs, similar to that found in human FF, on human granulosa tumor cell lines representing the juvenile (JGCT) and adult (AGCT) forms (COV434 and KGN cells, respectively). We found that all the individual compounds and mixtures tested altered granulosa tumor cell function by disrupting E2 secretion. In KGN cells, which possess significantly higher basal aromatase gene expression, and therefore secrete more E2 than JGCT cells, EDC mixtures activated estrogen receptors (ERs) and G protein-coupled receptor-30 signaling, thereby stimulating E2 secretion, without affecting aromatase expression. By contrast, in COV434 cells, which demonstrate higher CYP1A1 expression, a key mediator of estrogen metabolism, than KGN cells, EDC mixtures reduced E2 secretion in parallel with increases in the 2-hydroxyestrogen 1/E2 ratio and CYP1A1 expression, implying an upregulation of E2 metabolism. These results indicate that the EDC mixture present in FF disrupts E2 secretion in JGCT and AGCT cells according to the estrogen metabolic potential of the cell type, involving both classical and non-classical ER pathways.

Environmental Water Pollution, Endocrine Interference and Ecotoxicity of 4-tert-Octylphenol: A Review

4-tert-Octylphenol is a degradation product of non-ionic surfactants alkylphenol polyethoxylates as well as raw material for a number of industrial applications. It is a multimedia compound having been detected in all environmental compartments such as indoor air and surface waters. The pollutant is biodegradable, but certain degradation products are more toxic than the parent compound. Newer removal techniques from environmental waters have been presented, but they still require development for large-scale applications. Wastewater treatment by plant enzymes such as peroxidases offers promise in total removal of 4-tert-octylphenol leaving less toxic degradation products. The pollutant's endocrine interference has been well reported but more in oestrogens than in any other signalling pathways through which it is believed to exert toxicity on human and wildlife. In this paper we carried out a review of the activities of this pollutant in environmental waters, endocrine interference and relevance to its toxicities and concluded that inadequate knowledge of its endocrine activities impedes understanding of its toxicity which may frustrate current efforts at ridding the compound from the environment.

Pesticides in Surface Waters in Argentina Monitored Using Polar Organic Chemical Integrative Samplers

Polar Organic Chemical Integrative Samplers (POCIS) were deployed in two watersheds in Córdoba province and one watershed in Buenos Aires province in Argentina. The fungicides, tebuconazole, carbendazim and azoxystrobin, and the herbicides, atrazine, dicamba and 2,4-D were detected in POCIS deployed in each of the three watersheds. Estimated time weighted average concentrations of atrazine were greater than 2 µg/L at the outflow of Brava Lake in Buenos Aires province, and this concentration exceeds the Canadian water quality guideline for protection of aquatic life. The concentrations of all other pesticides were less than 400 ng/L. The distribution of pesticides detected in surface waters indicated that the sources were runoff from agricultural and urban lands and discharges from wastewater treatment plants.

Serum estradiol levels in infertile men with non-obstructive azoospermia

PURPOSE

To report the different patterns of estradiol levels in infertile men with non-obstructive azoospermia and correlate these levels with their clinical and laboratory findings.

MATERIALS AND METHODS

A retrospective study was launched, and a retrieval of data for infertile men with non-obstructive azoospermia (n = 166) and fertile controls (n = 40) was performed. The retrieved data included demographics, clinical findings, scrotal duplex, semen analysis, and hormonal assay (testosterone, follicle-stimulating hormone, luteinizing hormone, prolactin, and estradiol).

RESULTS

Our findings showed a wide spectrum of estradiol concentrations. The patients were arranged into three groups (high, normal, and low estradiol groups). The normal estradiol group was the most prevalent (71.1%). Testosterone, gonadotrophins, testicular volumes, and the number of patients with jobs in polluted workplaces showed significant differences among the study groups (p = 0.001, <0.001, <0.001, and 0.004, respectively). Age, body mass index, varicocele prevalence, prolactin, and smoking habits did not show any significant differences among the groups. Obesity was lacking in the low estradiol group, but it had significantly higher prevalence in the normal (p = 0.013) or high group (p = 0.023) compared with the controls.

CONCLUSION

Serum estradiol, in infertile men with non-obstructive azoospermia, may be present at different levels. It is recommended that estradiol be measured in infertile men with non-obstructive azoospermia when there is an alteration in testosterone concentration, obesity, a polluted workplace occupation, or before trying hormonal therapy. Extended studies are highly recommended to provide a clear clue whether alterations in estradiol concentrations in men with non-obstructive azoospermia are the cause or a consequence of the condition.