Multi-biomarker responses to pesticides in an agricultural population from Central Brazil

The Comet Assay as a Tool in Human Biomonitoring Studies of Environmental and Occupational Exposure to Chemicals-A Systematic Scoping Review

Biomonitoring of human populations exposed to chemical substances that can act as potential mutagens or carcinogens, may enable the detection of damage and early disease prevention. In recent years, the comet assay has become an important tool for assessing DNA damage, both in environmental and occupational exposure contexts. To evidence the role of the comet assay in human biomonitoring, we have analysed original research studies of environmental or occupational exposure that used the comet assay in their assessments, following the PRISMA-ScR method (preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews). Groups of chemicals were designated according to a broad classification, and the results obtained from over 300 original studies (n = 123 on air pollutants, n = 14 on anaesthetics, n = 18 on antineoplastic drugs, n = 57 on heavy metals, n = 59 on pesticides, and n = 49 on solvents) showed overall higher values of DNA strand breaks in the exposed subjects in comparison with the unexposed. In summary, our systematic scoping review strengthens the relevance of the use of the comet assay in assessing DNA damage in human biomonitoring studies.

Characterization of hepatotoxic effects induced by pyraclostrobin in human HepG2 cells and zebrafish larvae

Pyraclostrobin is a highly effective and broad-spectrum strobilurin fungicide. With the widespread use of pyraclostrobin to prevent and control crop diseases, its environmental pressure and potential safety risks to humans have attracted much attention. Herein, the toxicological risks of pyraclostrobin toward HepG2 cells and the mechanisms of intoxication in vitro were investigated. The liver toxicity of pyraclostrobin in zebrafish larvae was also evaluated. It was found that pyraclostrobin induced DNA damage and reactive oxygen species generation in HepG2 cells, indicating the potential genotoxicity of pyraclostrobin. The results of fluorescent staining experiments and the expression of cytochrome c, Bcl-2 and Bax demonstrated that pyraclostrobin induced mitochondrial dysfunction, resulting in cell apoptosis. Monodansylcadaverine staining and autophagy marker-related proteins LC3, p62, Beclin-1 protein expression showed that pyraclostrobin promoted cell autophagy. Furthermore, immunoblotting analysis suggested that pyraclostrobin induced autophagy accompanied with activation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/mTOR signaling pathway. Visualization of zebrafish liver and oil red staining indicated that pyraclostrobin could induce liver degeneration and liver steatosis in zebrafish. Collectively, these results help to better understand the hepatotoxicity of pyraclostrobin and provide a scientific basis for its safe applications and risk control.

Exposure to pesticide residues in honey and its potential cancer risk assessment

Honey is the most recognized natural food by-product derived from flower nectar and the upper aero-digestive tract of the honeybees. Significance of honey for its medicinal importance are well-documented in the world's oldest medical literatures. However, the current urbanization, environmental contaminations and changes in agricultural, as well as apiculture practices has led to various types of contaminations in honey. Among all, pesticide contamination has become one of the major issues worldwide. This review focuses on the recent updates concerning pesticides occurrence in honey, as well as how the repeated use and long-term exposure to honey contaminated with pesticide residues could affect the human physiological functions, possibly leading to the development of various cancers. Our findings suggests that uncontrolled use of pesticides in farming and apiculture practices leads to the occurrence of pesticides residues in honey. Therefore, regular consumption of such honey will pose a serious threat to human health, since most of the pesticides has been reported as potential carcinogens. This review will draw the attention of honey consumers, scientific communities, apiculture farmers, as well as governing bodies to strictly monitor the pesticide usage in floriculture, agriculture as well as other related practices.

Non-destructive methods to assess pesticide exposure in free-living bats

Bat populations are dwindling worldwide due to anthropogenic activities like agriculture, however the role that pesticide exposure plays on these declines is unclear. To address these research gaps, we first need to develop reliable methods to detect and monitor exposure to environmental pollutants and its effects on free-living bats. The use of biomarkers is a sensitive and informative tool to study sublethal effects in wildlife, however it requires laboratory validation and integrative approaches to be applicable to free-living species. In this study, we propose a set of non-destructive biomarkers to evaluate pesticide exposure in free-ranging bats and validated their suitability with dose-exposure experiments in captivity. We selected three biomarkers that have been widely used in vertebrate ecotoxicology and that combined represent sensitive, specific, and ecologically relevant responses to pollutants: DNA damage, AChE activity, and leukocyte profiles. We used two insectivorous bat species as model species Eptesicus fuscus (laboratory) and Pteronotus mexicanus (field). We found that micronuclei frequency (genotoxicity) and AChE activity (exposure and neurotoxicity) were robust indicators of toxicant exposure. The validity of this set of endpoints was supported by their consistent performance in laboratory and field experiments as well as by the significant correlation among them. Leukocyte profile (systemic stress) results were not consistent between laboratory and field studies, suggesting further evaluation of its suitability is needed. Integrative approaches, like the one we used here, maximize the insights about toxicant effects by combining the information of single biomarkers into more meaningful inferences, which can be applied to environmental risk assessments in wildlife. Furthermore, the use of non-destructive, cost-effective biomarkers is imperative when assessing toxicant exposure and effects in vulnerable wildlife and it should be a priority in the field of wildlife toxicology.

Comparison of the drinking water standard for pesticides of the Brazil with other countries

The objective was to compare the types and concentrations of pesticides allowed in the water potability standard for human supply in Brazil with other countries considered to be the largest consumers of pesticides in dollars invested in purchase/trade. This is a descriptive and documentary study, with data collection in regulations available in official government websites in Brazil, USA, China, Japan, France, Germany, Canada, Argentina, India, Italy, and World Health Organization (WHO). Since Germany, France and Italy are part of the European Union (EU), the legislative resolution of the European Parliament was adopted. Pesticides number and maximum permitted values (MPV) differ between the countries and WHO. In the Brazilian ordinance there are forty pesticides, a number like the USA, Canada, China, and WHO, but that represents only 8% of the total pesticides registered for agricultural use in Brazil. When comparing the ordinance of Brazil with EU the values are only the same for Aldrin + Dieldrin. For other, amounts between 2 and 5000 times more are allowed in Brazil. Brazilian regulations do not establish a total value for the mixture of pesticides in water, only individual limits, which together can reach 1677.13 μg/L, while in EU standards it is only 0.5 μg/L. The study showed discrepancies of the pesticides allowed in water potability standard of the Brazil with other countries, but features 12 pesticides with the same concentrations as WHO guidelines, thus, a worldwide standardization in water potability regulations is necessary to promote health and reducing risk of exposure.

Toxic effects of pesticides on cellular and humoral immunity: an overview

People are exposed to pesticides through food, drinking water, and the environment. These compounds are associated with several disorders, such as inflammatory diseases, rheumatoid arthritis, cancer, and a condition related to metabolic syndrome. The immunotoxicants or immunotoxic compounds can cause a wide variety of effects on immune function, altering humoral immunity and cell-mediated immunity, resulting in adverse effects to the body. Here, immune system disorders are highlighted because they are closely linked to multiple organs, including the nervous, endocrine, reproductive, cardiovascular, and respiratory systems, leading to transient or permanent changes. Therefore, this study reviewed the mechanisms involved in the immunotoxicity of fungicides, herbicides, and insecticides in cells, animals, and humans in the past 11 years. According to the studies analyzed, the pesticides interfere with innate and adaptive immune functions, but the effects observed mainly on cellular and humoral immunity were highlighted. These compounds affected specific immune cells, causing apoptosis, changes in factor nuclear kappa B (NF-κB) expression, pro-inflammatory factors interleukin 6 (IL-6), interleukin 8 (IL-8), interferon-gamma (IFN-γ), chemokines (CXCL-c1c), and anti-inflammatory factor, such as interleukin 10 (IL-10). To verify the threats of these compounds, new evaluations with immunotoxicological biomarkers are necessary. HighlightsPesticides interfere with the innate and adaptive immune response.Cells, animals and human studies demonstrate the immunotoxicity of pesticides in the cellular and humoral immune response.Fungicides, herbicides, and insecticides alter the immune system by various mechanisms, such as pro-inflammatory and anti-inflammatory factors.

Brazilian workers occupationally exposed to different toxic agents: A systematic review on DNA damage

The evaluation of genotoxicity in workers exposed to different toxic agents is very important, especially considering the association between these exposures in a chronic context and DNA damage. Assessing biomarkers of exposure and, when possible, early biomarkers of effect, contributes to elucidating the potential toxic mechanisms involved in genotoxicity and its contribution to chronic non-communicable diseases. In Brazil, the biggest country in South America, workers are exposed to hazardous physical and chemical agents. Considering that these exposures occur, in most cases, throughout the worker's whole life, this is an important public health concern in Brazil. Therefore, this systematic review aims to analyze occupational exposure to chemical and physical agents and the association with DNA damage in studies carried out in Brazil from 1980 to 2021. A systematic and comprehensive literature search was performed in different databases based on occupational exposure to chemical and physical agents and DNA damage. Only full articles on studies that investigated experimental evidence on occupational exposure in Brazil and assessed DNA damage were included, amounting to 89 articles. Five main occupational exposure groups were identified: pesticides (36%), organic solvents (20%), dust and particles (16%), metals (11%), and ionizing radiation (6%). Another group called "others" included studies (11%) that did not fall into these main groups. It was found that comet assay and micronucleus tests are the most adopted methods to detect DNA damage. Occupational exposures were most associated with DNA damage. However, further improvements in study design would be needed to better characterize the association between biomonitoring and DNA damage, particularly to account for confounding factors.

Exposure to Airborne Pesticides and Its Residue in Blood Serum of Paddy Farmers in Malaysia

Background: Pesticides manage pests and diseases in agriculture, but they harm the health of agricultural workers. Concentrations of thirteen pesticides were determined in personal air and blood serum of 85 paddy farmers and 85 non-farmers, thereafter associated with health symptoms. Method: Samples were analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Results: The median concentration of pesticides in personal air samples ranged from 10.69 to 188.49 ng/m3 for farmers and from 5.79 to 73.66 ng/m3 for non-farmers. The median concentration of pesticides in blood serum was from 58.27 to 210.12 ng/mL for farmers and 47.83 to 62.74 ng/mL for non-farmers. Concentration of eleven pesticides in personal air and twelve pesticides in blood serum were significantly higher in farmers than non-farmers (p < 0.05). All pesticides detected in personal air correlated significantly with concentration in the blood serum of farmers (p < 0.05). Health symptoms reported by farmers were dizziness (49.4%), nausea (47.1%), cough (35.3%), chest pain (30.6%), breathing difficulty (23.5%), sore throat (22.4%), vomiting (18.8%), phlegm (16.5%), and wheezing (15.3%). Concentration of pesticides in personal air, blood serum, and health symptoms were not significantly associated. Conclusion: Occupational exposure to pesticides significantly contaminates blood serum of farmers compared to non-farmers.

Impact of Pesticides on Human Health in the Last Six Years in Brazil

Every year, Brazil intensifies its activity in agriculture and, as a result, it has become one of the biggest consumers of pesticides in the world. The high rate of these substances raises environmental and human health concerns. Therefore, we collected papers from PubMed, Scopus, Scielo, and Web of Science databases, from 2015 to 2021. After a blind selection using the software Rayyan QCRI by two authors, 51 studies were included. Researchers from the South and the Southeast Brazilian regions contributed to most publications, from areas that concentrate agricultural commodity complexes. Among the pesticides described in the studies, insecticides, herbicides, and fungicides were the most frequent. The articles reported multiple toxic effects, particularly in rural workers. The results obtained can be used to direct policies to reduce the use of pesticides, and to protect the health of the population.

Cancer and occupational exposure to pesticides: a bibliometric study of the past 10 years

Occupational exposure to pesticides has been identified as a major trigger of the development of cancer. Pesticides can cause intoxication in the individuals who manipulate them through either inhalation, ingestion, or dermal contact. Given this, we investigated the association between the incidence of cancer and occupational exposure to pesticides through a bibliometric analysis of the studies published between 2011 and 2020, based on 62 papers selected from the Scopus database. The results indicated an exponential increase in the number of studies published over the past decade, with most of the research being conducted in the USA, France, India, and Brazil, although a further 17 nations were also involved in the research on the association between cancer and pesticides. The principal classes of pesticides investigated in relation to their role in intoxication and cancer were insecticides, herbicides, and fungicides. The types of cancer reported most frequently were multiple myeloma, bladder cancer, non-Hodgkin's lymphoma, prostate cancer, leukemia, and breast cancer. Despite the known association between pesticides and cancer, studies are still relatively scarce in comparison with the global scale of the use of these xenobiotic substances, which is related to the increasing demand for agricultural products throughout the world.

Exposure to environmental concentrations of natural pyrethrins induces hepatotoxicity: Assessment in HepG2 cell lines and zebrafish models

Natural pyrethrins are one variety of botanical pesticide, and are commonly used in organic and ecological agriculture. However, the hepatotoxicity of natural pyrethrins is unknown. In this study, the impact of natural pyrethrins on human HepG2 cells, which are prominent cell model for toxic-induced hepatotoxicity evaluations, was investigated in accordance with the ROS production and the mechanism of DNA damage and repair. And we report the liver toxicity of natural pyrethrins in zebrafish. Our result revealed a significant increase in ROS production, suggesting oxidative stress. Besides, the most notable genotoxic effect of oxidation-induced DNA damage was observed for natural pyrethrins, as detected by neutral comet assay and γH2AX/8-oxoG staining. As revealed by the results, oxidative DNA damage is responsible for the cytotoxic exposure of natural pyrethrins to HepG2 cells in humans. The observed damage is chronic toxicity, which may cause irreversible DNA damage and more severe toxic effects on human HepG2 cells. This can account for the complicated response to DNA impairment. Visual observations of zebrafish liver and oil red staining also demonstrated that natural pyrethrins induced liver degeneration, liver size changes and liver steatosis in zebrafish. In conclusion, the health of humans can be endangered by natural pyrethrins as a result of hepatotoxicity.

Evaluation of genotoxicity in bat species found on agricultural landscapes of the Cerrado savanna, central Brazil

Habitat loss and fragmentation together represent the most significant threat to the world's biodiversity. In order to guarantee the survival of this diversity, the monitoring of bioindicators can provide important insights into the health of a natural environment. In this context, we used the comet assay and micronucleus test to evaluate the genotoxic susceptibility of 126 bats of eight species captured in soybean and sugarcane plantation areas, together with a control area (conservation unit) in the Cerrado savanna of central Brazil. No significant differences were found between the specimens captured in the sugarcane and control areas in the frequency of micronuclei and DNA damage (comet assay). However, the omnivore Phyllostomus hastatus had a higher frequency of nuclear abnormalities than the frugivore Carollia perspicillata in the sugarcane area. Insectivorous and frugivorous bats presented a higher frequency of genotoxic damage than the nectarivores in the soybean area. In general, DNA damage and micronuclei were significantly more frequent in agricultural environments than in the control area. While agricultural development is an economic necessity in developing countries, the impacts on the natural landscape may result in genotoxic damage to the local fauna, such as bats. Over the medium to long term, then DNA damage may have an increasingly negative impact on the wellbeing of the local species.

Evidence on Human Exposure to Pesticides and the Occurrence of Health Hazards in the Brazilian Population: A Systematic Review

Brazil is among the biggest pesticide consumers in the world, with its population severely exposed to tons of such substances, both because of environmental contamination and occupational use. The health consequences of pesticide exposure are well-documented, but still sparse regarding Brazilian population. This study systematically reviewed the Brazilian studies published that address the relationship between exposure to pesticides and health problems in the Brazilian population. Also, information about pesticide use in Brazil is provided. The included studies showed that exposure to pesticides has a relevant impact on the health of the Brazilian population, regardless of age and gender, and on workers in rural areas or not. Most poisoning events seem to result from the continuous use of pesticides, whether occupationally or environmentally, characterizing a public health problem. The major consequences reported in literature were damage to the central nervous system, cancer, deleterious effects on rural workers' health, intoxications, malformations, and endocrine changes. These findings point out the need to understand the impact of chronic exposure to pesticides on severely exposed people and highlight the importance of creating public policies to protect them and avoid disease occurrence.

Farmers exposed to pesticides have almost five times more DNA damage: a meta-analysis study

We carried out a meta-analytical review of possible DNA damage resulting from occupational exposure to pesticides in farmers in the scientific literature. After the search, screening, and eligibility criteria steps, we included 42 studies to analyze random effect calculation. DNA damage in farmers occupationally exposed to pesticides represents an effect of SMD 4.63 [CI 95% 3.94-5.32; p <0.001]. We observed a high heterogeneity rate between the studies and an asymmetry of the bias analysis results. We performed a meta-regression on the parameters. The Olive Tail Moment (OTM) was the most effective comet assay parameter in the evaluated studies. The Damage Index (DI) was more conservative and highlighted the variability between studies caused by distinct methodologies that showed more significant effects and greater deviations. An analysis of confounding factors demonstrated a slight DNA damage in smokers who were occupationally exposed to pesticides compared to nonsmokers, indicating genotoxicity but smaller than the pesticide effect. The present study shows the greater risk that occupationally exposed rural workers have of developing related diseases due to pesticides' genotoxic effect.

Exposure to pesticides and oxidative stress in Brazilian agricultural communities

BACKGROUND

Oxidative stress may be an important mechanism linking pesticide exposure to several diseases. We evaluated the association between pesticide exposures and oxidative stress biomarkers in Brazilian agricultural workers.

METHODS

A cross-sectional study was conducted in healthy agricultural (N = 52) and non-agricultural workers (N = 68) in a rural community in Rio de Janeiro State, Brazil. Regular pesticide use, sociodemographic, and lifestyle information was obtained by questionnaire. Oxidative stress biomarkers (N = 7) were measured in serum and plasma. We calculated percent differences and 95% confidence intervals (CI) in oxidative stress biomarkers for use of pesticides adjusted for sex, age, education, smoking, and alcohol consumption, using multiple linear regression.

RESULTS

Living close to or in the fields was associated with glutathione peroxidase activity but not with any other markers. We observed significant positive associations between 8-isoprostane levels and activities of glutathione reductase, glutathione peroxidase, and glutathione-S-transferase with reported use of certain insecticides, fungicides, and herbicides. Our results also indicate a significant and negative association between glutathione-S-transferase activity and insecticide use.

CONCLUSIONS

These findings suggest that use of pesticides may be associated with differences in oxidative stress biomarkers.

Cytotoxicity and genotoxicity of methomyl, carbaryl, metalaxyl, and pendimethalin in human umbilical vein endothelial cells

Pesticides have adverse effects on the cellular functionality, which may trigger myriad of health consequences. However, pesticides-mediated toxicity in the endothelial cells (ECs) is still elusive. Hence, in this study, we have used human umbilical vein endothelial cells (HUVECs) as a model to quantify the cytotoxicity and genotoxicity of four pesticides (methomyl, carbaryl, metalaxyl, and pendimethalin). In the MTT assay, HUVECs exposed to methomyl, carbaryl, metalaxyl, and pendimethalin demonstrated significant proliferation inhibition only at higher concentrations (500 and 1000 μM). Likewise, neutral red uptake (NRU) assay also showed proliferation inhibition of HUVECs at 500 and 1000 μM by the four pesticides, confirming lysosomal fragility. HUVECs exposed to the four pesticides significantly increased the level of intracellular reactive oxygen species (ROS). Comet assay and flow cytometric data exhibited DNA damage and apoptotic cell death in HUVECs after 24 h of exposure with methomyl, metalaxyl, carbaryl, and pendimethalin. This is a first study on HUVECs signifying the cytotoxic-genotoxic and apoptotic potential of carbamate insecticides (methomyl and carbaryl), fungicide (metalaxyl), and herbicide (pendimethalin). Overall, these pesticides may affect ECs functions and angiogenesis; nonetheless, mechanistic studies are warranted from the perspective of vascular biology using in vivo test models.