Alachlor Use and Cancer Incidence in the Agricultural Health Study: An Updated Analysis

Exposure to Pesticides and Breast Cancer in an Agricultural Region in Brazil

Rural workers are disproportionally exposed to pesticides and might be at an increased risk of developing chronic diseases. Here, we investigated the impact of pesticide exposure on breast cancer (BC) risk and disease profile in rural female workers. This is a case-control study that prospectively included 758 individuals. The study was conducted in the Southwest region of Paraná state in Brazil, a region characterized by family-based agriculture and intensive use of pesticides. We found that this region has a 41% higher BC diagnosis rate and 14% higher BC mortality rate than the mean rates in Brazil, as well as a pesticide trade volume about 6 times higher than the national average. We showed substantial exposure in this population and found that even women who did not work in the fields but performed equipment decontamination and clothes washing of male partners who worked in the fields had urine samples positive for glyphosate, atrazine, and/or 2,4-D. The crude association showed a significantly higher risk of BC among women exposed to pesticides (OR: 1.58, 95% CI 1.18-2.13). Adjusted analyses showed a lower and nonstatistically significant association (OR: 1.30, 95% CI 41 0.87-1.95). Stratification on disease profile showed a significantly higher risk of lymph node metastasis (adjusted OR: 2.19, 95% CI 1.31-3.72) in women exposed to pesticides. Our findings suggest that female populations exposed to pesticides are at a higher risk of developing BC with a more aggressive profile and draw attention to the need to monitor rural populations potentially exposed to pesticides in the field or at home.

Protein quality control systems in the endoplasmic reticulum and the cytosol coordinately prevent alachlor-induced proteotoxic stress in Saccharomyces cerevisiae

Alachlor, a widely used chloroacetanilide herbicide for controlling annual grasses in crops, has been reported to rapidly trigger protein denaturation and aggregation in the eukaryotic model organism Saccharomyces cerevisiae. Therefore, this study aimed to uncover cellular mechanisms involved in preventing alachlor-induced proteotoxicity. The findings reveal that the ubiquitin-proteasome system (UPS) plays a crucial role in eliminating alachlor-denatured proteins by tagging them with polyubiquitin for subsequent proteasomal degradation. Exposure to alachlor rapidly induced an inhibition of proteasome activity by 90 % within 30 min. The molecular docking analysis suggests that this inhibition likely results from the binding of alachlor to β subunits within the catalytic core of the proteasome. Notably, our data suggest that nascent proteins in the endoplasmic reticulum (ER) are the primary targets of alachlor. Consequently, the unfolded protein response (UPR), responsible for coping with aberrant proteins in the ER, becomes activated within 1 h of alachlor treatment, leading to the splicing of HAC1 mRNA into the active transcription activator Hac1p and the upregulation of UPR gene expression. These findings underscore the critical roles of the protein quality control systems UPS and UPR in mitigating alachlor-induced proteotoxicity by degrading alachlor-denatured proteins and enhancing the protein folding capacity of the ER.

Magnetite-driven Bio-Fenton degradation of chloroacetanilide herbicides by a newly isolated hydrogen peroxide producing bacterium Desemzia sp. strain C1

The efficiency of the Fenton reaction is markedly contingent upon the operational pH related to iron solubility. Therefore, a heterogeneous Fenton reaction has been developed to function at neutral pH. In the present study, the Bio-Fenton reaction was carried out using magnetite (Fe(II)Fe(III)2O4) and H2O2 generated by a newly isolated H2O2-producing bacterium, Desemzia sp. strain C1 at pH 6.8 to degrade chloroacetanilide herbicides. The optimal conditions for an efficient Bio-Fenton reaction were 10 mM of lactate, 0.5% (w/v) of magnetite, and resting-cells (O.D.600 = 1) of strain C1. During the Bio-Fenton reaction, 1.8-2.0 mM of H2O2 was generated by strain C1 and promptly consumed by the Fenton reaction with magnetite, maintaining stable pH conditions. Approximately, 40-50% of the herbicides underwent oxidation through non-specific reactions of •OH, leading to dealkylation, dechlorination, and hydroxylation via hydrogen atom abstraction. These findings will contribute to advancing the Bio-Fenton system for non-specific oxidative degradation of diverse organic pollutants under in-situ environmental conditions with bacteria producing high amount of H2O2 and magnetite under a neutral pH condition.

Chemical contaminants in blood and their implications in chronic diseases

Artificial chemical products are widely used and ubiquitous worldwide and pose a threat to the environment and human health. Accumulating epidemiological and toxicological evidence has elucidated the contributions of environmental chemical contaminants to the incidence and development of chronic diseases that have a negative impact on quality of life or may be life-threatening. However, the pathways of exposure to these chemicals and their involvements in chronic diseases remain unclear. We comprehensively reviewed the research progress on the exposure risks of humans to environmental contaminants, their body burden as indicated by blood monitoring, and the correlation of blood chemical contaminants with chronic diseases. After entering the human body through various routes of exposure, environmental contaminants are transported to target organs through blood circulation. The application of the modern analytical techniques based on human plasma or serum specimens is promising for determining the body burden of environmental contaminants, including legacy persistent organic pollutants, emerging pollutants, and inorganic elements. Furthermore, their body burden, as indicated by blood monitoring correlates with the incidence and development of metabolic syndromes, cancers, chronic nervous system diseases, cardiovascular diseases, and reproductive disorders. On this basis, we highlight the urgent need for further research on environmental pollution causing health problems in humans.

Insights into the metabolic pathways and biodegradation mechanisms of chloroacetamide herbicides

Chloroacetamide herbicides are widely used around the world due to their high efficiency, resulting in increasing levels of their residues in the environment. Residual chloroacetamides and their metabolites have been frequently detected in soil, water and organisms and shown to have toxic effects on non-target organisms, posing a serious threat to the ecosystem. As such, rapid and efficient techniques that eliminate chloroacetamide residues from the ecosystem are urgently needed. Degradation of these herbicides in the environment mainly occurs through microbial metabolism. Microbial strains such as Acinetobacter baumannii DT, Bacillus altitudinis A16, Pseudomonas aeruginosa JD115, Sphingobium baderi DE-13, Catellibacterium caeni DCA-1, Stenotrophomonas acidaminiphila JS-1, Klebsiella variicola B2, and Paecilomyces marquandii can effectively degrade chloroacetamide herbicides. The degradation pathway of chloroacetamide herbicides in aerobic bacteria is mainly initiated by an N/C-dealkylation reaction, followed by aromatic ring hydroxylation and cleavage processes, whereas dechlorination is the initial reaction in anaerobic bacteria. The molecular mechanisms associated with bacterial degradation of chloroacetamide herbicides have been explored, with amidase, hydrolase, reductase, ferredoxin and cytochrome P450 oxygenase currently known to play a pivotal role in the catabolic pathways of chloroacetamides. The fungal pathway for the degradation of these herbicides is more complex with more diversified products, and the degradation enzymes and genes involved remain to be discovered. However, there are few reviews specifically summarizing the microbial degrading species and biochemical mechanisms of chloroacetamide herbicides. Here, we briefly summarize the latest progress resulting from research on microbial strain resources and enzymes involved in degradation of these herbicides and their corresponding genes. Furthermore, we explore the biochemical pathways and molecular mechanisms for biodegradation of chloroacetamide herbicides in depth, thereby providing a reference for further research on the bioremediation of such herbicides.

Development and validation of an LC-MS/MS assay with multiple stage fragmentation for the quantification of alachlor in McF-7 cells

Alachlor is one of the most widely used herbicides and can also be a carcinogenic compound. It is of great significance to establish a sensitive analytical method for the determination of alachlor in the environment and organisms. In this study, a high-performance liquid chromatography tandem mass spectrometry cubed (LC/MS³) method was developed and validated to quantify alachlor in human breast cancer cells (McF-7 cells). The cell samples were processed by simple protein precipitation with acetonitrile, then the analytes were separated on a Waters AcQuity® UPLC BEH (2.1 × 50 mm I.D, 1.7 μm) column using the gradient elution with solvent A (0.1 % formic acid) and solvent B (acetonitrile) at a flow rate of 0.5 mL/min. MS³ detection in positive ion mode was used to detect the analytes. The MRM³ transitions at m/z 270.1 → 238.0 → 162.1 and 312.2 → 238.1 → 147.2 were used to determine alachlor and butachlor, respectively. The run time for each sample was only 4 min. This method was validated for various parameters including accuracy, precision, selectivity, linearity, lower limit of quantitation (LLOQ), etc. The LC/MS³ assay was linear in the concentration range 0.5-50 ng/mL (R² ≥ 0.995). For all concentrations, the precision is < 9.49 %, and the intra-day and intra-day accuracy is < 13.05 %. Cytotoxic potential of alachlor against McF-7 cell lines was measured by MTT method after 48 h of incubation. For alachlor, half maximal inhibitory concentration (IC₅₀) on McF-7 cells was 87.95 µg/mL. This method was successfully applied to cellular pharmacokinetic study of alachlor in McF-7 cells after administration with a dose of 20 μg/mL.

Associations of organophosphate metabolites with thyroid hormone and antibody levels: findings from U.S. National Health and Nutrition Examination Survey (NHANES)

Studies have shown that organophosphate pesticides (OPs) exposure may disrupt thyroid endocrine functions in animal models, agricultural population, occupational workers, and work-related population. However, the relationships between OPs exposure and thyroid hormone levels in the general population are unclear. This study aimed to explore the relationships of OPs exposure with thyroid hormone and antibody levels in the general population. We analyzed a sample of 1089 US adults from the National Health and Nutrition Examination Survey (NHANES) 2001-2002. OPs exposure was estimated using measures of six non-specific dialkyl phosphate metabolites (DAPs), e.g., dimethylphosphate (DMP). Multiple linear regression models were used to examine the associations of OPs exposure with thyroid hormone and antibody levels. The medians of urinary ∑DAPs detected in males and females were 32.98 nmol/g creatinine and 40.77 nmol/g creatinine, with statistical significance (p = 0.001). After controlling for sociodemographic factors, we found that concentrations of urinary OPs metabolites were positively associated with the serum thyroid stimulating hormone (TSH) in the general US population, particularly in males; OPs metabolites were associated with the serum TgAb, tT3, fT3, and TSH. These findings showed that thyroid hormone and antibody disruption are probably associated with OPs exposure in the general population; more studies are needed to confirm our findings.

Dye-Encapsulated Lanthanide-Based Metal-Organic Frameworks as a Dual-Emission Sensitization Platform for Alachlor Sensing

As an important factor affecting global agricultural output, pesticides have a significant impact on the ecosystem. It is an urgent task to accurately and conveniently detect pesticide residues after their application. Herein, a fluorescent dye@MOF platform was designed via the encapsulation of rhodamine B (RhB) into the MOF structure (named RhB@HNU-48), which can significantly enhance the sensing sensitivity of alachlor with an ultralow detection limit of 0.59 ppb. The improved sensitivity of RhB@HNU-48 to pesticides was attributed to the host-guest interactions that affect the excitation and emission spectra of the composites. Based on the sensing capability of RhB@HNU-48, a logic gate was built to evaluate the safety level of alachlor residues in rivers and soil. The preparation of photofunctionalized MOF composites through modulation of host-guest interactions offers a promising strategy for the construction of desired sensors for agricultural residues.

Non-specific degradation of chloroacetanilide herbicides by glucose oxidase supported Bio-Fenton reaction

Bio-Fenton reaction supported by glucose oxidase (GOx) for producing H₂O₂ was applied to degrade persistent chloroacetanilide herbicides in the presence of Fe (Ⅲ)-citrate at pH 5.5. There were pH decrease to 4.3, the production of 8 mM H₂O₂ and simultaneous consumption to produce •OH radicals which non-specifically degraded the herbicides. The degradation rates followed the order acetochlor ≈ alachlor ≈ metolachlor > propachlor ≈ butachlor with the degradation percent of 72.8%, 73.4%, 74.0%, 47.4%, and 43.8%, respectively. During the Bio-Fenton degradation, alachlor was dechlorinated and filtered into catechol via the production of intermediates formed through a series of hydrogen atom abstraction and hydrogen oxide radical addition reactions. The current Bio-Fenton reaction leading to the production of •OH radicals could be applied for non-specific oxidative degradation to various persistent organic pollutants under in-situ environmental conditions, considering diverse microbial metabolic systems able to continuously supply H₂O₂ with ubiquitous Fe(II) and Fe(III) and citrate.

Exposição a agrotóxicos e desenvolvimento de câncer no contexto da saúde coletiva: o papel da agroecologia como suporte às políticas públicas de prevenção do câncer

RESUMO Atualmente, a agricultura brasileira é caracterizada pelo crescente consumo de agrotóxicos e fertilizantes químicos, inserindo-se no modelo de produção baseado nos fundamentos do agronegócio. As novas técnicas de cultivo baseadas no agronegócio resultaram na expansão das monoculturas sobre os ecossistemas naturais, com o consequente desmatamento, desequilíbrio e perda da biodiversidade; e o aumento da contaminação do solo, da água e do ar pelos agrotóxicos. No que tange à saúde humana, a literatura científica tem demonstrado que a contaminação química decorrente do uso de agrotóxicos na agricultura implica adoecimento dos trabalhadores rurais expostos ocupacionalmente aos agrotóxicos, dos moradores da área rural, além de consumidores de alimentos contendo resíduos de agrotóxicos. Entre os efeitos sobre a saúde humana associados à exposição a agrotóxicos, os mais preocupantes são as intoxicações crônicas, caracterizadas por infertilidade, abortos, malformações congênitas, neurotoxicidade, desregulação hormonal, imunotoxicidade, genotoxicidade e câncer. Sendo assim, neste ensaio, apresenta-se uma revisão narrativa com dados presentes na literatura científica nacional e internacional referentes à associação entre a exposição a agrotóxicos e o desenvolvimento de câncer no contexto da saúde coletiva e o papel da alimentação saudável e da agroecologia como suporte às políticas públicas de prevenção do câncer.

A systematic review and meta-analysis of occupational exposures and risk of follicular lymphoma

BACKGROUND

The etiology of follicular lymphoma (FL), a common non-Hodgkin lymphoma subtype, is largely unknown.

OBJECTIVE

We performed a systematic review and meta-analysis of observational studies examining the relationship between occupational exposures and FL risk.

METHODS

We searched Ovid MEDLINE, Ovid EMBASE, and Web of Science for eligible observational studies examining job titles or occupational exposures prior to January 1, 2020. We performed a narrative synthesis and used random-effects models to generate meta-estimates of relative risk (RR) with 95% confidence intervals (95%CI) for exposures reported by three or more studies.

RESULTS

Fifty-eight studies were eligible. Ten cohort and 37 case-control studies quantified FL risk in relation to any exposure to one or more occupational groups or agents. Eight cohort and 19 case-control studies examined dose-response relationships. We found evidence of a positive association with increasing plasma concentration of dichlorodiphenyldichloroethylene (DDE; meta-RR = 1.51, 95%CI = 0.99, 2.31; I² = 0.0%) and polychlorinated biphenyls (PCBs; meta-RR = 1.47, 95%CI = 0.97, 2.24; I² = 8.6%). We observed a positive association with exposure to any solvent (meta-RR = 1.16, 95%CI = 1.00, 1.34; I² = 0.0%) and chlorinated solvents (meta-RR = 1.35, 95%CI = 1.09, 1.68; I² = 0.0%). Single studies reported a significant positive dose-response association for exposure to any pesticide, hexachlorobenzene, any organophosphate, diazinon, metolachlor, carbaryl, lindane, trichloroethylene, oils/greases, and extremely low-frequency magnetic fields. Job title-only analyses suggested increased risk for medical doctors and spray painters, and decreased risk for bakers and teachers. Overall, studies demonstrated low risk of bias, but most studies examined small numbers of exposed cases.

CONCLUSIONS

Current evidence indicates a positive association between FL and occupational exposure to DDE, PCBs, any solvent and chlorinated solvents. Our findings may help guide policies and practices on the safe use of solvents and inform models of lymphomagenesis. Future studies with larger sample sizes and comprehensive quantitative exposure measures may elucidate other avoidable carcinogenic exposures.

Dicamba use and cancer incidence in the agricultural health study: an updated analysis

BACKGROUND

The herbicide dicamba has been commonly used agriculturally and residentially. Recent approval of genetically engineered dicamba-resistant crops is expected to lead to increased dicamba use, and there has been growing interest in potential human health effects. A prior analysis in the Agricultural Health Study (AHS) suggested associations between dicamba and colon and lung cancer. We re-evaluated dicamba use in the AHS, including an additional 12 years and 2702 exposed cancers.

METHODS

The AHS is a prospective cohort of pesticide applicators in Iowa and North Carolina. At enrollment (1993-1997) and follow-up (1999-2005), participants reported dicamba use. Exposure was characterized by cumulative intensity-weighted lifetime days, including exposure lags of up to 20 years. We estimated relative risks (RR) and 95% confidence intervals (CI) using multivariable Poisson regression for incident cancers diagnosed from enrollment through 2014/2015.

RESULTS

Among 49 922 applicators, 26 412 (52.9%) used dicamba. Compared with applicators reporting no dicamba use, those in the highest quartile of exposure had elevated risk of liver and intrahepatic bile duct cancer (nexposed = 28, RRQ4 = 1.80, CI: 1.26-2.56, Ptrend < 0.001) and chronic lymphocytic leukaemia (CLL, nexposed = 93, RRQ4 = 1.20, CI: 0.96-1.50, Ptrend = 0.01) and decreased risk of myeloid leukaemia (nexposed = 55, RRQ4 = 0.73, CI: 0.51-1.03, Ptrend = 0.01). The associations for liver cancer and myeloid leukaemia remained after lagging exposure of up to 20 years.

CONCLUSIONS

With additional follow-up and exposure information, associations with lung and colon cancer were no longer apparent. In this first evaluation of liver and intrahepatic bile duct cancer, there was an association with increasing use of dicamba that persisted across lags of up to 20 years.

Synthetic Pesticides and Health in Vulnerable Populations: Agricultural Workers

PURPOSE OF REVIEW

This review aims to summarize epidemiological literature published between May 15, 2018, and May 14, 2019, that examines the relationship between exposure to synthetic pesticides and health of agricultural workers.

RECENT FINDINGS

Current research suggests that exposure to synthetic pesticides may be associated with adverse health outcomes. Agricultural workers represent a potentially vulnerable population, due to a combination of unique social and cultural risk factors as well as exposure to hazards inherent in agricultural work. Pesticide exposure among agricultural workers has been linked to certain cancers, DNA damage, oxidative stress, neurological disorders, and respiratory, metabolic, and thyroid effects. This review describes literature suggesting that agricultural workers exposed to synthetic pesticides are at an increased risk of certain cancers and neurological disorders. Recent research on respiratory effects is sparse, and more research is warranted regarding DNA damage, oxidative stress, metabolic outcomes, and thyroid effects.

Challenging the concept of de novo acute myeloid leukemia: Environmental and occupational leukemogens hiding in our midst

Myeloid neoplasms like acute myeloid leukemia (AML) originate from genomic disruption, usually in a multi-step fashion. Hematopoietic stem/progenitor cell acquisition of abnormalities in vital cellular processes, when coupled with intrinsic factors such as germline predisposition or extrinsic factors such as the marrow microenvironment or environmental agents, can lead to requisite pre-leukemic clonal selection, expansion and evolution. Several of these entities have been invoked as "leukemogens." The known leukemogens are numerous and are found in the therapeutic, occupational and ambient environments, however they are often difficult to implicate for individual patients. Patients treated with particular chemotherapeutic agents or radiotherapy accept a calculated risk of therapy-related AML. Occupational exposures to benzene, dioxins, formaldehyde, electromagnetic and particle radiation have been associated with an increased risk of AML. Although regulatory agencies have established acceptable exposure limits in the workplace, accidental exposures and even ambient exposures to leukemogens are possible. It is plausible that inescapable exposure to non-anthropogenic ambient leukemogens may be responsible for many cases of non-inherited de novo AML. In this review, we discuss the current understanding of leukemogens as they relate to AML, assess to what extent the term "de novo" leukemia is meaningful, and describe the potential to identify and characterize new leukemogens.

Human exposure to bisphenol AF and diethylhexylphthalate increases susceptibility to develop differentiated thyroid cancer in patients with thyroid nodules

Pollutants represent potential threats to the human health, being ubiquitous in the environment and exerting toxicity even at low doses. This study aims at investigating the role of fifteen multiclass organic pollutants, assumed as markers of environmental pollution, most of which exerting endocrine-disrupting activity, in thyroid cancer development. The increasing incidence of differentiated thyroid cancer (DTC) may be related to the rising production and environmental dissemination of pollutants. Fifty-five patients, twenty-seven with diagnosis of benign thyroid nodules and twenty-eight suffering from differentiated thyroid cancer, were enrolled and the concentration levels of seven bisphenols, two phthalates (i.e. di(2-ethylhexyl) phthalate (DEHP) and its main metabolite, mono-(2-ethyl-hexyl) phthalate) (MEHP)), two chlorobenzenes, (1,4-dichlorobenzene and 1,2,4,5-tetrachlorobenzene), and 3 phenol derivatives (2-chlorophenol, 4- nonylphenol, and triclosan) were determined in their serum by using a validated analytical method based on high performance liquid chromatography with ultraviolet tandem fluorescence detection. A significant relationship was found between malignancy and the detection in the serum of both bisphenol AF and DEHP. Indeed, their presence confers a more than fourteen times higher risk of developing differentiated thyroid cancer. Relationship between these two pollutants and the risk of malignancy was dose-independent and not mediated by higher thyroid stimulating hormone levels. Even if a conclusive evidence cannot still be drawn and larger prospective studies are needed, the exposure to low doses of environmental endocrine-disrupting contaminants can be considered consistent with the development of thyroid cancer.

Cancer incidence in the Agricultural Health Study after 20 years of follow-up

PURPOSE

To evaluate cancer incidence in the Agricultural Health Study (AHS), a cohort of private pesticide applicators, their spouses, and commercial applicators, based on 12,420 cancers, adding 5,989 cancers, and 9 years of follow-up since last evaluation.

METHODS

We calculated age, year, sex, and race-adjusted standardized incidence ratios (SIR) and 95% confidence intervals (CI) for cancer sites in the AHS relative to the general population.

RESULTS

Overall AHS cancer incidence was lower than the general population (SIR_private = 0.91, CI 0.89-0.93; SIR_spouse = 0.89, CI 0.86-0.92; SIR_commercial = 0.83, CI 0.76-0.92), with notable deficits across applicators and spouses for oral cavity, pancreas, and lung cancers. Cancer excesses included prostate cancer, lip cancer, certain B-cell lymphomas (e.g., multiple myeloma), acute myeloid leukemia (AML), thyroid cancer, testicular cancer, and peritoneal cancer. The lung cancer deficit was strongest among applicators reporting potential exposure to endotoxin at study enrollment (tasks such as raising animals and handling stored grain).

CONCLUSIONS

Although an overall deficit in cancer was observed, there were notable exceptions, including newly observed excesses for AML, thyroid, testicular, and peritoneal cancers. Furthermore, endotoxin exposure may, in part, account for observed lung cancer incidence deficits. Cancer incidence patterns in the AHS suggest farm exposures' relevance to cancer etiology.

Exposição ocupacional a agrotóxicos, riscos e práticas de segurança na agricultura familiar em município do estado do Espírito Santo, Brasil

Resumo Objetivo: caracterizar a exposição ocupacional, percepção do risco, práticas de segurança e fatores associados ao uso de equipamento de proteção individual (EPI) durante a manipulação de agrotóxicos. Métodos: estudo transversal com amostra representativa de agricultores de Santa Maria de Jetibá, Espírito Santo. Procedeu-se à caracterização sociodemográfica e ocupacional dos agricultores com exposição direta a agrotóxicos e a identificação dos ingredientes ativos e classificação toxicológica dos produtos utilizados. Resultados: foram referidas 106 marcas comerciais, 45 grupos químicos e 77 ingredientes ativos. Houve predomínio do herbicida glifosato. Dos 550 agricultores avaliados 89% referiram uso de agrotóxicos extremamente tóxicos, 56,3% utilizavam mais de cinco agrotóxicos e 51% trabalhavam há mais de 20 anos em contato direto com estes produtos. Metade não lia rótulo dos agrotóxicos, mais de um terço não observava o tempo de carência para colheita e reaplicação e nem o de reentrada na lavoura; 71,4% não utilizavam EPI ou utilizavam de forma incompleta. Entre os fatores associados à não utilização do EPI, destaca-se a classe socioeconômica (p = 0,002), baixa escolaridade (p = 0,05), falta de suporte técnico (p < 0,001) e não leitura dos rótulos (p < 0,001). Conclusão: os agricultores apresentaram exposição ocupacional prolongada a múltiplos agrotóxicos de elevada toxidade, referindo práticas inseguras de manuseio.