Organochlorine and organophosphorus pesticides and bladder cancer: A case-control study

Effects of sub-lethal concentrations of lindane on histo-morphometric and physio-biochemical parameters of Labeo rohita

Lindane is a broad-spectrum insecticide widely used on fruits, vegetables, crops, livestock and on animal premises to control the insects and pests. The extensive use of pesticides and their residues in the soil and water typically join the food chain and thus accumulate in the body tissues of human and animals causing severe health effects. The study was designed to determine the toxicity effects of sub-lethal concentrations of lindane on hemato-biochemical profile and histo-pathological changes in Rohu (Labeo rohita). A significant increase in the absolute (p<0.05) and relative (p<0.05) weights was observed along with severe histo-pathological alterations in liver, kidneys, gills, heart and brain at 30μg/L and 45μg/L concentration of lindane. A significant (p<0.05) decrease in RBCs count, PCV and Hb concentration while a significant (p<0.05) increased leukocytes were observed by 30μg/L and 45μg/L concentrations of lindane at 45 and 60 days of the experiment. Serum total protein and albumin were significantly (p<0.05) decreased while hepatic and renal enzymes were significantly (p<0.05) increased due to 30μg/L and 45μg/L concentrations of lindane at days-45 and 60 of experiment compared to control group. The observations of thin blood smear indicated significantly increased number of erythrocytes having nuclear abnormalities in the fish exposed at 30μg/L and 45μg/L concentrations of lindane. ROS and TBARS were found to be significantly increased while CAT, SOD, POD and GSH were significantly decreased with an increase in the concentration and exposure time of lindane. The results showed that lindane causes oxidative stress and severe hematological, serum biochemical and histo-pathological alterations in the fish even at sub-lethal concentrations.

β-Hexachlorocyclohexane triggers neuroinflammatory activity, epigenetic histone post-translational modifications and cognitive dysfunction

Persistent organic pollutants (POPs), which encompass pesticides and industrial chemicals widely utilized across the globe, pose a covert threat to human health. β-hexachlorocyclohexane (β-HCH) is an organochlorine pesticide with striking stability, still illegally dumped in many countries, and recognized as responsible for several pathogenetic mechanisms. This study represents a pioneering exploration into the neurotoxic effects induced by the exposure to β-HCH specifically targeting neuronal cells (N2a), microglia (BV-2), and C57BL/6 mice. As shown by western blot and qPCR analyses, the administration of β-HCH triggered a modulation of NF-κB, a key factor influencing both inflammation and pro-inflammatory cytokines expression. We demonstrated by proteomic and western blot techniques epigenetic modifications in H3 histone induced by β-HCH. Histone acetylation of H3K9 and H3K27 increased in N2a, and in the prefrontal cortex of C57BL/6 mice administered with β-HCH, whereas it decreased in BV-2 cells and in the hippocampus. We also observed a severe detrimental effect on recognition memory and spatial navigation by the Novel Object Recognition Test (NORT) and the Object Place Recognition Task (OPRT) behavioural tests. Cognitive impairment was linked to decreased expression of the genes BDNF and SNAP-25, which are mediators involved in synaptic function and activity. The obtained results expand our understanding of the harmful impact produced by β-HCH exposure by highlighting its implication in the pathogenesis of neurological diseases. These findings will support intervention programs to limit the risk induced by exposure to POPs. Regulatory agencies should block further illicit use, causing environmental hazards and endangering human and animal health.

Polymorphisms in drug-metabolizing genes and urinary bladder cancer susceptibility and prognosis: Possible impacts and future management

Epidemiological studies have shown the association of genetic variants with risks of occupational and environmentally induced cancers, including bladder (BC). The current review summarizes the effects of variants in genes encoding phase I and II enzymes in well-designed studies to highlight their contribution to BC susceptibility and prognosis. Polymorphisms in genes codifying drug-metabolizing proteins are of particular interest because of their involvement in the metabolism of exogenous genotoxic compounds, such as tobacco and agrochemicals. The prognosis between muscle-invasive and non-muscle-invasive diseases is very different, and it is difficult to predict which will progress worse. Web of Science, PubMed, and Medline were searched to identify studies published between January 1, 2010, and February 2023. We included 73 eligible studies, more than 300 polymorphisms, and 46 genes/loci. The most studied candidate genes/loci of phase I metabolism were CYP1B1, CYP1A1, CYP1A2, CYP3A4, CYP2D6, CYP2A6, CYP3E1, and ALDH2, and those in phase II were GSTM1, GSTT1, NAT2, GSTP1, GSTA1, GSTO1, and UGT1A1. We used the 46 genes to construct a network of proteins and to evaluate their biological functions based on the Reactome and KEGG databases. Lastly, we assessed their expression in different tissues, including normal bladder and BC samples. The drug-metabolizing pathway plays a relevant role in BC, and our review discusses a list of genes that could provide clues for further exploration of susceptibility and prognostic biomarkers.

Pets, Genuine Tools of Environmental Pollutant Detection

In a shared environment, our companion animals became unintended sentinels for pollutant exposure consequences, developing even earlier similar conditions to humans. This review focused on the human-pet cohabitation in an environment we all share. Alongside other species, canine and feline companions are veritable models in human medical research. The latency period for showing chronic exposure effects to pollutants is just a few years in them, compared to considerably more, decades in humans. Comparing the serum values of people and their companion animals can, for example, indicate the degree of poisonous lead load we are exposed to and of other substances as well. We can find 2.4 times higher perfluorochemicals from stain- and grease-proof coatings in canine companions, 23 times higher values of flame retardants in cats, and 5 times more mercury compared to the average levels tested in humans. All these represent early warning signals. Taking these into account, together with the animal welfare orientation of today's society, finding non-invasive methods to detect the degree of environmental pollution in our animals becomes paramount, alongside the need to raise awareness of the risks carried by certain chemicals we knowingly use.

Organochlorine pesticides and epigenetic alterations in thyroid tumors

Purpose

Cancer incidence depends on various factors e.g., pesticide exposures which cause epigenetic alterations. The present research aimed to investigate the organochlorine pesticides (OCPs) impacts on promoter methylation of three tumor-suppressor genes and four histone modifications in thyroid nodules in 61 Papillary thyroid carcinoma (PTC) and 70 benign thyroid nodules (BTN) patients.

Methods

OCPs were measured by Gas chromatography. To identify promoter methylation of TSHR, ATM, and P16 genes, the nested-methylation-specific PCR (MSP) was utilized, and histone lysine acetylation (H3K9, H4K16, and H3K18) and lysine methylation (H4K20) were detected by performing western blot analysis.

Results

Further TSHR methylation and less P16 methylation were observed in PTC than in BTN. No substantial difference was detected for ATM methylation between PTC and BTN groups. Also, OCP dramatically increased the odds ratio of TSHR (OR=3.98, P=0.001) and P16 (OR=5.65, P<0.001) methylation while confounding variables reduced the chances of ATM methylation arising from 2,4-DDE and 4,4-DDT influence. Hypomethylation of H4K20 and hypo-acetylation of H3K9, H4K16, and H3K18 (P<0.001) were observed in PTC samples than BTN. Furthermore, OCPs substantially decreased the odds ratio of H3K9 (OR=3.68, P<0.001) and H4K16 (OR=6.03, P<0.001) acetylation.

Conclusion

The current research indicated that OCPs could contribute to PTC progression by TSHR promoter hypermethylation and decreased acetylation of H3K9 and H4K16. In addition, in PTC patients, assessing TSHR promoter methylation and acetylation of H3K9 and H4K16 could have predictive values.

Pesticides and Bladder Cancer: Mechanisms Leading to Anti-Cancer Drug Chemoresistance and New Chemosensitization Strategies

Multiple risk factors have been associated with bladder cancer. This review focuses on pesticide exposure, as it is not currently known whether agricultural products have a direct or indirect effect on bladder cancer, despite recent reports demonstrating a strong correlation. While it is known that pesticide exposure is associated with an increased risk of bladder cancer in humans and dogs, the mechanism(s) by which specific pesticides cause bladder cancer initiation or progression is unknown. In this narrative review, we discuss what is currently known about pesticide exposure and the link to bladder cancer. This review highlights multiple pathways modulated by pesticide exposure with direct links to bladder cancer oncogenesis/metastasis (MMP-2, TGF-β, STAT3) and chemoresistance (drug efflux, DNA repair, and apoptosis resistance) and potential therapeutic tactics to counter these pesticide-induced affects.

Revelation of bioremediation approaches for hexachlorocyclohexane degradation in soil

This review elucidates different bioremediation approaches used for degradation of HCH from contaminated sites. It highlights the significance of degradative pathways, microbial diversity and impact of different environmental factors for developing viable bioremediation strategies. The application of innovative biotechnological approaches and a thorough understanding of HCH biodegradation pathways show great promise for the creation of long-term solutions to HCH pollution and the restoration of polluted soil ecosystems. Bioremediation technologies viz. biostimulation, bioaugmentation, phytoremediation have been considered till date for treating HCH-contaminated sites. Different bacterial and fungal strains have been reported for degradation of HCH residues. However, these methods are limited to γ-HCH degradation, at laboratory scale and achieving lower success rate for large scale demonstration trials. This review presents a theoretical background for degradation of different HCH isomers in soil through plants, microbes and through their cooperative interactions. This work briefly overviews the substantial contamination of the environment by HCH residues, along with spontaneous evolution of degradation pathways through various HCH degrading microbes. Bioremediation mechanism and pathways of HCH degradation through plants and microbes have been discussed thoroughly. Through molecular and genetic investigations, the complex metabolic pathways used by these microbes, including reductive dechlorination, hydrolysis, and ring cleavage, has been clarified. This study seeks to give a thorough summary of recent discoveries and developments in bioremediation methods for soil HCH degradation. Numerous microbial consortia, including fungi, plants, and bacteria have been recognised as important participants in the transformation of HCH.

Construction of a ratiometric fluorescent sensing platform based on near-infrared carbon dots for organophosphorus pesticides detection

In this work, a convenient ratiometric fluorescent platform was designed to measure organophosphorus pesticides (OPs) based on acetylcholinesterase (AChE), acetylthiocholine (ATCh), manganese dioxide nanosheets (MnO₂), near-infrared carbon dots (RCDs) and o-phenylenediamine (OPD). In this platform, a direct oxidation of OPD by MnO₂ generated the luminescent product 2,3-diaminophenolazine (DAP) through intrinsic oxidase activity, while RCDs served as a fluorescent reference indicator. In the presence of AChE and ATCh, the enzymatic hydrolysate thiocholine (TCh) would reduce MnO₂ nanosheets to Mn²⁺, leading to the quenching of DAP fluorescence. On the other hand, OPs can inhibit the catabolism of ATCh by AChE thus acting as a recognizer of OPs. According to these reactions, OPs were quantitatively analyzed by the intensity ratio of fluorescence emitted from RCDs and DAP (F₅₆₀/F₆₇₆). The constructed platform can detect OPs with the range of 0.2-0.6 μM with a detection limit of 4.3 nM. Figure A ratiometric fluorescent probe based on carbon dots was obtained and using it to determine the concentration of organophosphorus pesticides.

Organochlorine pesticides induce thyroid tumors through oxidative stress; an in vivo and in silico study

Thyroid disease is one of the most common endocrine problems around the world. Among the numerous factors, exposure to environmental elements such as pesticides is associated with an increase in the incidence of thyroid disorders. The aim of the present study was to investigate the role of organochlorine pesticides (OCPs) in induction of oxidative stress (OS) and development of thyroid tumors. This case-control study was conducted on 61 patients with papillary thyroid carcinoma (PTC), 70 patients with benign thyroid nodules (BTN), and 73 healthy individuals as control. Seven derived OCPs residues measured by gas chromatography (GC), and enzyme activities of acetylcholinesterase (AChE), superoxide dismutase3 (SOD3), catalase (CAT), glutathione peroxidase3 (GPx3) and paraoxonase1 (PON1) and also, non-enzymatic antioxidant including; malondialdehyde (MDA), total antioxidant capacity (TAC), protein carbonyl (PC), and nitric oxide (NO) biomarkers in all participants were investigated. Furthermore, all of the above enzymes were docked against measured OCPs. The results revealed that β-HCH, γ-HCH, 2,4 DDE, 4,4 DDE, 2,4-DDT, and 4,4-DDT levels along with MDA, NO, and PC levels were elevated, while AChE, SOD3, GPx3, CAT, and PON1 activities and TAC levels were decreased in the PTC and BTN groups compared with the control group. Therefore, OCPs might play a role in the development of thyroid tumors through several mechanisms including generation of OS. Importantly, in silico analysis confirmed the in vivo findings.

Exposures to pesticides and risk of cancer: Evaluation of recent epidemiological evidence in humans and paths forward

Knowledge of the role in cancer etiology of environmental exposures as pesticides is a prerequisite for primary prevention. We review 63 epidemiological studies on exposure to pesticides and cancer risk in humans published from 2017 to 2021, with emphasis on new findings, methodological approaches, and gaps in the existing literature. While much of the recent evidence suggests causal relationships between pesticide exposure and cancer, the strongest evidence exists for acute myeloid leukemia (AML) and colorectal cancer (CRC), diseases in which the observed associations were consistent across several studies, including high-quality prospective studies and those using biomarkers for exposure assessment, with some observing dose-response relationships. Though high-quality studies have been published since the IARC monograph on organophosphate insecticides in 2017, there are still gaps in the literature on carcinogenic evidence in humans for a large number of pesticides. To further knowledge, we suggest leveraging new techniques and methods to increase sensitivity and precision of exposure assessment, incorporate multi-omics data, and investigate more thoroughly exposure to chemical mixtures. There is also a strong need for better and larger population-based cohort studies that include younger and nonoccupationally exposed individuals, particularly during developmental periods of susceptibility. Though the existing evidence has limitations, as always in science, there is sufficient evidence to implement policies and regulatory action that limit pesticide exposure in humans and, hence, further prevent a significant burden of cancers.

Biomonitoring of organochlorine pesticides and cancer survival: a population-based study

Organochlorine pesticides (OCPs) are endocrine-disrupting chemicals (EDCs) that even at very low levels can cause cancer by increasing the activity of tumor cells and suppressing the immune system. There is also little information on OCPs and survival after diagnosis. The aim of this study was to monitor the concentration of OCPs in the blood serum of cancer patients and its relationship with their socio-demographic characteristics and ultimately that impact on survival time and hazard ratio (HR). This cross-sectional study included 89 diagnosed patients with cancer in Isfahan, Iran. 12 types of OCPs were measured in serum by gas chromatography (7GC) with an electron capture detector and equipped with mass spectrometer (MS). Also, participants' questionnaire was completed to collect information. T-test, ANOVA, and Chi-square tests were used to evaluate the association between serum levels of OCPs and quantitative and qualitative information of patients. Survival analysis was also examined based on Kaplan-Meier method, log-rank test, and Cox model. The mean of total OCPs in patients' serum was calculated to be 1.82 ± 1.36 μg/L. Concentration of 2,4' DDE had a significant relationship with body mass index (BMI) (kg/m²) (P < 0.05). In addition, gender revealed a significant correlation in estimating survival time (P < 0.05). Non-exposure to OCPs showed a positive effect on increasing the life expectancy of patients. Lindane and endosulfan increased the risk of death by 16% and 37%, respectively, with insignificant P value (P > 0.05). The findings of the present study showed adverse effects of OCPs on patients' survival time and increased mortality of HR. Moreover, as the first research conducted in the study area, it is suggested management of environmental, individual and social factors that could be influenced the biological accumulation of OCPs in humans and cause health promotion.

Occupational exposure to pesticides in farmworkers and the oxidative markers

Organophosphate (OPPs) and organochlorine pesticides (OCPs) are the two predominant forms of pesticides extensively used all around the world and are being reconsidered as environmental pollutants. The current study sought to assess the role of socioeconomic factors on the level of pesticides residues and the oxidative effects of exposure to OPPs and OCPs among the farmworkers of southeast Iran. In this cross-sectional study, 192 farmworkers and 74 non-farmworkers (controls) were involved. Gas chromatography (GC) was performed to measure the serum levels of organochlorine chemicals (2,4-DDT, 4,4-DDT, 2,4-DDE, 4,4-DDE, α-HCH, β-HCH, and γ-HCH). Furthermore, acetylcholinesterase (AChE) activity, arylesterase activity of paraoxonase-1 (PON-1), and several oxidative stress (OS) markers were assessed. In addition, the impact of several parameters such as home to farm distance, education level, ventilation status, and personal protective equipment (PPE) on pesticide levels was analyzed. The levels of OCPs in the farmworkers were significantly higher than the control subjects. In addition, AChE activity, arylesterase activity of PON-1, and total antioxidant capacity in farmworkers were significantly less, and MDA levels were higher than the controls. Education level was associated with farmworkers' protective behavior. The current findings suggested that some phased out OCPs can still be measured in human samples in the southeast of Iran. Furthermore, the current study demonstrated that exposure to OCPs and OPPs was accompanied by adverse consequences regarding OS parameters and subsequent health problems. In addition, the findings of the present study suggest that improving farmworkers' education might be associated with reduced exposure to pesticides and less adverse health effects.

Differential Bioaccumulation Patterns of α, β-Hexachlorobenzene and Dicofol in Adipose Tissue from the GraMo Cohort (Southern Spain)

To identify bioaccumulation patterns of α-, β- hexachlorocyclohexane (HCH) and dicofol in relation to sociodemographic, dietary, and lifestyle factors, adipose tissue samples of 387 subjects from GraMo cohort in Southern Spain were analyzed. Potential predictors of these organochlorine pesticides (OCP) levels were collected by face-to-face interviews and assessed by multivariable linear and logistic regression. OCPs were detected in 84.2% (β-HCH), 21.7% (α-HCH), and 19.6% (dicofol) of the population. β-HCH levels were positively related to age, body mass index (BMI), mother's occupation in agriculture during pregnancy, living in Poniente and Alpujarras, white fish, milk and water consumption, and negatively related to being male, living near to an agricultural area, working ≥10 years in agriculture, and beer consumption. Detectable α-HCH levels were positively related to age, BMI, milk consumption, mother's occupation in agriculture during pregnancy, and negatively with residence in Poniente and Alpujarras, Granada city, and Granada Metropolitan Area. Residence near to an agricultural area, smoking habit, white fish and water consumption, and living in Poniente and Alpujarras, Granada city and Granada Metropolitan Area were negatively associated with detectable dicofol levels. Our study revealed different bioaccumulation patterns of α, β-HCH and dicofol, probably due to their dissimilar period of use, and emphasize the need for assessing the exposure to frequently overlooked pollutants.

Geospatial Assessment of Pesticide Concentration in Ambient Air and Colorectal Cancer Incidence in Arkansas, 2013-2017

Exposure to various agricultural pesticides has been linked to colorectal cancer (CRC), mostly among farmworkers and applicators. Given the potential pesticide drift in ambient air, residents near farmland may be exposed to carcinogenic pesticides even if they are not actively engaged in pesticide application. Pesticide air pollution at the county level was estimated using the 2014 National Air Toxics Assessment. CRC incidence data were acquired from the Arkansas Central Cancer Registry for 2013-2017. We ran ordinary least squares (OLS) regression models, finding significant spatial autocorrelation of residuals for most models. Using geographically weighted regression (GWR) we found age-adjusted CRC incidence rates vary in an increasing west-to-east gradient, with the highest rates in the Arkansas Delta region. A similar gradient was observed in the distribution of the population living below the poverty line and the population percentage of Black people. Significant associations between Trifluralin (crude model only), Carbon Tetrachloride, and Ethylene Dibromide with CRC incidence rates in OLS models only explained 5-7% of the variation and exhibited spatial autocorrelation of residuals. GWR models explained 24-32% (adjusted r² 9-16%) of CRC incidence rate variation, suggesting additional factors may contribute to the association between pesticides and CRC.

Gradual reduction of susceptibility and enhanced detoxifying enzyme activities of laboratory-reared Aedes aegypti under exposure of temephos for 28 generations

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Aedes aegypti mosquitoes were exposed to temephos for 28 generations.

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This exposure led to a 7.83-fold decrease in temephos toxicity.

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With increase in generational time, Ae. aegypti exhibited increased detoxification.

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Increased detoxification correlated with increase in detoxifying enzymes.

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Repeated exposure of Ae. aegypti to temephos could lead to pesticide resistance.

Temephos, an organophosphate insecticide, is widely accepted for the control of Aedes aegypti, vector of infectious diseases such as dengue, chikungunya, yellow fever, and zika. However, there are claims that repeated and indiscriminate use of temephos has resulted in resistance development in exposed mosquito populations. The present study attempts to evaluate the continuous performance of temephos on the Ae. aegypti population, in laboratory conditions, in terms of toxicity and the effect on marker enzymes associated with metabolic resistance. Results of the toxicity bioassay showed that after the initial exposure, toxicity increased till F4 generation by 1.65 fold, and continuous exposure resulted in a 7.83 fold reduction in toxicity at F28 generation. Percent mortality result showed a marked reduction in mortality with the passage of generations while using the same series of concentrations, viz. 2 ppm, which was 100 % lethal at the initial nine generations, could kill only 22.66 % at F28. Resistance to organophosphates is mainly governed by metabolic detoxifying enzyme families of esterases, glutathione-s-transferase, and cytochrome P450. Analysis of these metabolic detoxifying enzymes showed an inverse trend to toxicity (i.e. toxicity increased in early generations as enzyme activity dropped and then dropped as enzyme activity increased). At the initial exposure, enzyme activity decreased in 2–4 generations, however, repeated exposure led to a significant increase in all the metabolic detoxifying enzymes. From the toxicity level as well as marker enzyme bioassay results, it can be inferred that mosquitoes showed increased detoxification in generational time with an increase in enzymes associated with metabolic detoxification. In conclusion, repeated application of temephos led to resistance development in Ae. aegypti which may be associated with the increase in metabolic detoxifying enzyme activities.

Pesticide exposure and related health problems among farmworkers' children: a case-control study in southeast Iran

Pesticides are potentially hazardous chemicals that can cause injury to human health and the environment. The purpose of this study was to evaluate organophosphate pesticides (OPPs) and organochlorine pesticides (OCPs) exposure in farmworkers' children aged 6 to 11 years in Jiroft city in southeastern Iran. One hundred twenty farmworkers' children as case and 53 non-farmworkers' children aged 6 to 11 years as control were selected and the serum levels of OCPs were measured by using gas chromatography in all participants. In addition, erythrocyte acetylcholinesterase (AChE) and arylesterase activity of paraoxonase-1 (PON-1) were measured to evaluate OPPs effects. Catalase (CAT), superoxide dismutase3 (SOD3), glutathione peroxidase (GPx3) activities, and the levels of serum malondialdehyde (MDA), total antioxidant capacity (TAC), nitric oxide (NO), and protein carbonyl (PC) were measured to investigate OCPs and OPPs effects on oxidative stress (OS). The serum levels of beta-HCH, 4,4 DDE, and 4,4 DDT in the case group were significantly higher than the control group. In addition, in the case group, AChE, PON-1, CAT, SOD3, and GPx3 activities and the levels TAC were significantly lower, while MDA, PC, and NO levels were significantly higher than the control group. OCPs as illegal pesticides are present in southeast Iran and children are exposed to OCPs and OPPs in the studied area. In addition, higher serum levels of pesticides may be a major contributor in OS development, as a cause of many diseases.

Cancer risk and nullity of Glutathione-S-transferase mu and theta 1 in occupational pesticide workers

Occupational exposure to pesticides has been associated with adverse health conditions, including genotoxicity and cancer. Nullity of GSTT1/GSTM1 increases the susceptibility of pesticide workers to these adverse health effects due to lack of efficient detoxification process created by the absence of these key xenobiotic metabolizing enzymes. However, this assertion does not seem to maintain its stance at all the time; some pesticide workers with the null genotypes do not present the susceptibility. This suggests the modulatory role of other confounding factors, genetic and environmental conditions. Pesticides, aggravated by the null GSTT1/GSTM1, cause genotoxicity and cancer through oxidative stress and miRNA dysregulation. Thus, the absence of these adverse health effects together with the presence of null GSTT1/GSTM1 genotypes demands further explanation. Also, understanding the mechanism behind the protection of cells - that are devoid of GSTT1/GSTM1 - from oxidative stress constitutes a great challenge and potential research area. Therefore, this review article highlights the recent advancements in the presence and absence of cancer risk in occupational pesticide workers with GSTT1 and GSTM1 null genotypes.

Multiple Roles of Mesoporous Silica in Safe Pesticide Application by Nanotechnology: A Review

Pollution related to pesticides has become a global problem due to their low utilization and non-targeting application, and nanotechnology has shown great potential in promoting sustainable agriculture. Nowadays, mesoporous silica-based nanomaterials have garnered immense attention for improving the efficacy and safety of pesticides due to their distinctive advantages of low toxicity, high thermal and chemical stability, and particularly size tunability and versatile functionality. Based on the introduction of the structure and synthesis of different types of mesoporous silica nanoparticles (MSNs), the multiple roles of mesoporous silica in safe pesticide application using nanotechnology are discussed in this Review: (i) as nanocarrier for sustained/controlled delivery of pesticides, (ii) as adsorbent for enrichment or removal of pesticides in aqueous media, (iii) as support of catalysts for degradation of pesticide contaminants, and (iv) as support of sensors for detection of pesticides. Several scientific issues, strategies, and mechanisms regarding the application of MSNs in the pesticide field are presented, with their future directions discussed in terms of their environmental risk assessment, in-depth mechanism exploration, and cost-benefit consideration for their continuous development. This Review will provide critical information to related researchers and may open up their minds to develop new advances in pesticide application.

Prenatal exposure to organochlorine pesticides is associated with increased risk for neural tube defects

Neural tube defects (NTDs) are among the most common and disabling fetal congenital defects. Organochlorine pesticides (OCPs) are ubiquitous in the environment. In this study, 119 women who had NTD-affected pregnancies (cases) and 119 women who delivered healthy neonates (controls) were recruited in a rural area of Northern China. We used concentrations of OCPs in umbilical cord tissue as markers of prenatal exposure to investigate the association between in utero exposure to OCPs and NTD risk. Concentrations of 20 OCPs were quantified by gas chromatography-mass spectrometry, and 16 of the 20 OCPs were included in the analyses. Odds ratios and 95% confidence intervals (95% CIs) for the associations between levels of individual OCPs and NTD risk were estimated separately with logistic regression adjusting for potential confounders. The combined effects of exposure to the 16 OCPs as a mixture were analyzed with Bayesian kernel machine regression (BKMR). Logistic regression showed that the risk for NTDs increased 5.44-fold (95% CI, 2.21-13.41) for β-hexachlorocyclohexane, 2.51-fold (95% CI, 1.07-5.86) for endosulfan I, 3.78-fold (95% CI, 1.60-8.89) for endosulfan II, 3.42-fold (95% CI, 1.44-8.12) for ο,ρ'-dichlorodiphenyldichloroethane, and 2.89-fold (95% CI, 1.22-6.86) for ρ,ρ'-dichlorodiphenyltrichloroethane when the concentration of each of these OCPs was above its median (exposed) compared to below its median (non-exposed). Other OCPs were not associated with NTD risk in multivariate models. In BKMR, NTD risk increased almost linearly with concentrations of the 16 OCPs as a mixture, which suggests joint effects on NTD risk. Exposure to α-hexachlorocyclohexane, β-hexachlorocyclohexane, endosulfan II, ο,ρ'-dichlorodiphenyldichloroethane, and ρ,ρ'-dichlorodiphenyldichloroethane was associated with an increased risk for NTDs when levels of the remaining 15 OCPs were taken into account. Taken together, these findings show that prenatal exposure to OCPs is associated with increased risk for NTDs.

Pesticide exposure and related health problems among family members of farmworkers in southeast Iran. A case-control study

BACKGROUND

Pesticides used in agriculture are some of the most common pollutants in the world. This study aimed to investigate the effects of Organophosphorus Pesticides (OPPs) and Organochlorine Pesticides (OCPs) on the families of farmworkers in the southeast of Iran.

METHODS

In the present case-control study, 141 family members of farmworkers (as the case group) and 59 family members of non-farmworkers (as the controls) were recruited. Serum levels of OCPs such as α-HCH, β-HCH, γ-HCH, 2,4-DDE, 4,4-DDE, 2,4-DDT, and 4,4-DDT were determined. In addition, erythrocyte acetylcholinesterase (AChE) activity, malondialdehyde (MDA), total antioxidant capacity (TAC), protein carbonyl (PC), nitric oxide (NO) serum levels, arylesterase activity of paraoxonase 1 (PON-1), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity were determined in all participants. Furthermore, distance to farmlands, education, crops, type, and the number of consumed fruits were evaluated for each individual separately.

RESULTS

The erythrocyte AChE activity and serum activities of GPx, SOD, and PON-1 and TAC levels were significantly decreased, whereas the concentration of MDA, PC, NO, and seven OCPs were significantly increased in the farmworkers' families as compared to the controls. Spearman correlation and linear regression suggest that OCPs increase the oxidative stress in farmworkers' family members. Moreover, distance, education, farming precedence, products, and ventilation had significant effects on the OCP levels and increased the odds ratio of OCP levels in farmworkers' families.

CONCLUSION

With regards to the data obtained in this study, it was revealed that OCPs as illegal pesticides and OPPs were higher than expected in the farmworkers' family members. Furthermore, exposure to OCPs and OPPs, apart from the other effects on the body, leads to oxidative stress (OS) that may cause serious diseases in the exposed populations.

Immune response of Brazilian farmers exposed to multiple pesticides

Occupational exposure to pesticides has been identified as a factor that predisposes to disorders of the immune system. Immunosuppression, autoimmunity, cancer of various organs and other diseases in people who apply these products have been reported by the studies. This study aimed to investigate the relationship between occupational exposure to pesticides and the immunological profile in 43 farmers exposed to mixtures of pesticides for at least 15 years. A control group composed of 30 individuals without a history of occupational exposure to pesticides was also evaluated. Peripheral blood samples were processed by flow cytometry and cells were labelled with an 8-color monoclonal antibody panel. Plasma cytokines were also measured. Significant increase in classical monocytes (p < 0.001) and dendritic cells (p < 0.001) in the exposed group was observed as well in total T cells (p = 0.04), central memory CD8 T cells (p = 0.02) and effector memory CD8 T cells (p = 0.01). On the other hand, the activation markers of T cells as the expression of CD57, HLA-DR, CD25 and CD28 were evaluated and no difference was found between groups. When the B cells were analyzed, a significant decrease in total B cells (p = 0.01), regulatory B cells (p < 0.001) and plasmablasts (p < 0.001) in the exposed group, compared to healthy controls, was observed. Pro-inflammatory IL-6 was significantly elevated (p = 0.04) in the plasma of farmers compared to that of controls. The constant antigenic stimulus that occurs during exposure to pesticides can favor the recruitment of dendritic cells and macrophages (APCs) presents in the skin and respiratory tract. In the secondary lymphoid organs, the CD4 T and B cells that process such antigens are possibly undergoing proliferative exhaustion, with the consequent depletion of all mature B subpopulations. The resulting drop in humoral immunity may be offset by an increase in the number of circulating CD8 T lymphocytes due to their cytotoxic action.

Insights Into the Biodegradation of Lindane (γ-Hexachlorocyclohexane) Using a Microbial System

Lindane (γ-hexachlorocyclohexane) is an organochlorine pesticide that has been widely used in agriculture over the last seven decades. The increasing residues of lindane in soil and water environments are toxic to humans and other organisms. Large-scale applications and residual toxicity in the environment require urgent lindane removal. Microbes, particularly Gram-negative bacteria, can transform lindane into non-toxic and environmentally safe metabolites. Aerobic and anaerobic microorganisms follow different metabolic pathways to degrade lindane. A variety of enzymes participate in lindane degradation pathways, including dehydrochlorinase (LinA), dehalogenase (LinB), dehydrogenase (LinC), and reductive dechlorinase (LinD). However, a limited number of reviews have been published regarding the biodegradation and bioremediation of lindane. This review summarizes the current knowledge regarding lindane-degrading microbes along with biodegradation mechanisms, metabolic pathways, and the microbial remediation of lindane-contaminated environments. The prospects of novel bioremediation technologies to provide insight between laboratory cultures and large-scale applications are also discussed. This review provides a theoretical foundation and practical basis to use lindane-degrading microorganisms for bioremediation.

Gene-environment interactions between GSTs polymorphisms and targeted epigenetic alterations in hepatocellular carcinoma following organochlorine pesticides (OCPs) exposure

Exposure to environmental pollutant organochlorine pesticides (OCPs) and the role of tumour suppressor GSTs gene polymorphisms as well as epigenetic alterations have all been well reported in hepatocarcinogenesis. However, the interplay between environmental risk factors and polymorphic tumour suppressor genes or epigenetic factors in hepatocellular carcinoma (HCC) development remains ambiguous. Herein, we investigated the relationship of three GSTs polymorphisms (GSTT1 deletion, GSTM1 deletion, GSTP1 rs1695) as well as GSTP1 promoter region DNA methylation and HCC risk with a particular focus on the interaction with OCPs exposure among 90 HCC cases and 99 controls in a Chinese population. Serum samples were analysed for OCPs exposure employing gas chromatography coupled with mass selective detector (GC-MS). GSTs polymorphisms and epigenetic alterations were determined using high-resolution melting PCR (HRM PCR) and DNA sequencing. After adjusting for confounders (HBV infection, smoking, alcohol consumption, BMI, age, gender), OCPs exposure and GSTP1 methylation is significantly associated with elevated risk of HCC, while no significance is observed for GSTs polymorphisms. Moreover, the effects of OCPs exposure on HCC risk are more pronounced amongst GSTP1 (Ile/Val + Val/Val) and GSTP1 promoter methylation subjects than those who were GSTP1 (Ile/Ile) and unmethylated subjects. The interactions between OCPs exposure and GSTP1 genotype as well as GSTP1 epigenetic status are statistically significant. The current study demonstrates the importance of gene-environment interactions in the multifactorial development of HCC.