Is organic farming safer to farmers' health? A comparison between organic and traditional farming

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.

Exposure Levels of Pyrethroids, Chlorpyrifos and Glyphosate in EU-An Overview of Human Biomonitoring Studies Published since 2000

Currently used pesticides are rapidly metabolised and excreted, primarily in urine, and urinary concentrations of pesticides/metabolites are therefore useful biomarkers for the integrated exposure from all sources. Pyrethroid insecticides, the organophosphate insecticide chlorpyrifos, and the herbicide glyphosate, were among the prioritised substances in the HBM4EU project and comparable human biomonitoring (HBM)-data were obtained from the HBM4EU Aligned Studies. The aim of this review was to supplement these data by presenting additional HBM studies of the priority pesticides across the HBM4EU partner countries published since 2000. We identified relevant studies (44 for pyrethroids, 23 for chlorpyrifos, 24 for glyphosate) by literature search using PubMed and Web of Science. Most studies were from the Western and Southern part of the EU and data were lacking from more than half of the HBM4EU-partner countries. Many studies were regional with relatively small sample size and few studies address residential and occupational exposure. Variation in urine sampling, analytical methods, and reporting of the HBM-data hampered the comparability of the results across studies. Despite these shortcomings, a widespread exposure to these substances in the general EU population with marked geographical differences was indicated. The findings emphasise the need for harmonisation of methods and reporting in future studies as initiated during HBM4EU.

Risk Factors for Brain Health in Agricultural Work: A Systematic Review

Certain exposures related to agricultural work have been associated with neurological disorders. To date, few studies have included brain health measurements to link specific risk factors with possible neural mechanisms. Moreover, a synthesis of agricultural risk factors associated with poorer brain health outcomes is missing. In this systematic review, we identified 106 articles using keywords related to agriculture, occupational exposure, and the brain. We identified seven major risk factors: non-specific factors that are associated with agricultural work itself, toluene, pesticides, heavy metal or dust exposure, work with farm animals, and nicotine exposure from plants. Of these, pesticides are the most highly studied. The majority of qualifying studies were epidemiological studies. Nigral striatal regions were the most well studied brain area impacted. Of the three human neuroimaging studies we found, two focused on functional networks and the third focused on gray matter. We identified two major directions for future studies that will help inform preventative strategies for brain health in vulnerable agricultural workers: (1) the effects of moderators such as type of work, sex, migrant status, race, and age; and (2) more comprehensive brain imaging studies, both observational and experimental, involving several imaging techniques.

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.

Pyrethroid based pesticides - chemical and biological aspects

Human and animal welfare primarily depends on the availability of food and surrounding environment. Over a century and half, the quest to identify agents that can enhance food production and protection from vector borne diseases resulted in the identification and use of a variety of pesticides, of which the pyrethroid based ones emerged as the best choice. Pesticides while improved the quality of life, on the other hand caused enormous health risks. Because of their percolation into drinking water and food chain and usage in domestic settings, humans unintentionally get exposed to the pesticides on a daily basis. The health hazards of almost all known pesticides at a variety of doses and exposure times are reported. This review provides a comprehensive summation on the historical, epidemiological, chemical and biological (physiological, biochemical and molecular) aspects of pyrethroid based insecticides. An overview of the available knowledge suggests that the synthetic pyrethroids vary in their chemical and toxic nature and pose health hazards that range from simple nausea to cancers. Despite large number of reports, studies that focused on identifying the health hazards using doses that are equivalent or relevant to human exposure are lacking. It is high time such studies are conducted to provide concrete evidence on the hazards of consuming pesticide contaminated food. Policy decisions to decrease the residual levels of pesticides in agricultural products and also to encourage organic farming is suggested.

Occupational exposure to pesticides: Genetic danger to farmworkers and manufacturing workers - A meta-analytical review

In the last decades, the use of pesticides has grown worldwide. However, there is great worry about the impact of pesticides on human health, due to their wide distribution and possible long-term effects. Complex mixtures with different formulations are often used, including a variety of genotoxic compounds. Thus, genotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. This study aimed to conduct a meta-analytical review of possible genetic damage resulting from occupational exposure in farmworkers and workers employed in pesticide production, both ever in comparison to non-exposed people, using comet assay (CA), micronucleus test (MN) and telomere length (TL) data available in the scientific literature. A total of 145 datasets were evaluated. The results showed that the occupationally exposed workers had more DNA damage in CA and MN than non-exposed workers. The TL result did not show difference between groups. When the data were categorized by gender (male, female or both), crop (general, tobacco, fruits, soybeans, cotton) and occupation (manufacturing or farmworkers), the study found that the exposed group always presented higher damage than the non-exposed individuals, in CA and MN. More studies with TL are needed to obtain a more precise response, and to segregate the effect of tobacco farming from pesticide exposure. When TL was segregated by gender, women and men presented difference between exposed and non-exposed groups. In general, the publication bias impact was modest. If all relevant studies were included, the key finding (i.e. the effect of pesticide exposure increases the genotoxicity and mutation rate) would probably remain unchanged. Lastly, it is important to highlight the importance of the use of personal protective equipment (PPE), and offer safer options to farmworkers (e.g. organic farming or less toxic alternatives).

Perceptions about Healthy Eating and Emotional Factors Conditioning Eating Behaviour: A Study Involving Portugal, Brazil and Argentina

This study analysed the perceptions about healthy eating as well as some emotional factors conditioning eating behaviour in a sample of people from Portugal, Brazil and Argentina. This is a descriptive cross-sectional study involving a non-probabilistic sample of 2501 participant. Data was collected through a questionnaire applied to adult citizens residing in their respective countries. For data analysis chi-square tests were used, and associations were evaluated by Cramer's coefficients. Moreover, a tree classification analysis was conducted for variables related with perceptions about healthy eating and emotional conditioning of eating behaviour. The results revealed that participants' perceptions are generally in agreement with healthy eating. However, significant differences were found between countries (p = 0.018) and by levels of education (p < 0.0005), with a more accurate perception for Portugal and at the university level. The existence of statistically significant associations between all sociodemographic variables considered and the conditioning of eating behaviour by emotional motivations should be noted. Tree classification analysis showed that the most important discriminant sociodemographic variable for perceptions about healthy eating was education, followed by professional area and country, while the most relevant discriminants for emotional conditioning of eating behaviour were country and then living environment and sex. Thus, it is important to consider these variables in initiatives that aim to promote adherence to behaviours that contribute to the health and well-being of the population.

Biomarkers of occupational exposure to pesticides: Systematic review of insecticides

INTRODUCTION

Pesticides are widely used around the world, and rural workers have greater risk of poisoning. The use of biomarkers for insecticides can contribute to the diagnosis and prevention of poisoning.

OBJECTIVE

To identify, in the scientific literature, the biomarkers of occupational exposure to insecticides of different insecticide classes.

METHODS

The PubMed, Lilacs and Embase databases were analyzed using a systematic search strategy and in accordance with the criteria established by the PRISMA methodology. Articles with information related to the use of biomarkers to identify active ingredients, or insecticide metabolites, or effects on the human biological matrices were analyzed.

RESULTS

A total of 840 studies was found, and 30 met the selection criteria. The search identified 118 results for insecticide biomarkers, of which 45% were of exposure, 42% of effect, and 14% of susceptibility. Additionally, 78 were possible biomarkers, and only 67 confirmed to be different biomarkers for insecticides. Acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 3,5,6-trichloro-2-pyridinol (TCP-y), specific for Chlorpyrifos, were among the most common biomarkers identified; however, most metabolites found were non-specific.

CONCLUSION

Various insecticide biomarkers were mentioned; nonetheless, only a few are specific and used to identify the wide range of insecticides to which farm workers are exposed.

A model of farmers intentions towards organic farming: A case study on rice farming in Thailand

Determining the factors that influence intentions towards organic farming (IOF) is a challenge. This research applied the theory of planned behaviour to determine factors which influence farmers'. There are six causal factors: attitudes towards farming behaviour, group-norm influences on farming behaviour, perceived behavioural control of farmers, comparative usefulness of behaviours, perceived of risk of farming and support of government policy. The purpose of this article is to explore the influential factors for conserving and cumulating organic farming behaviours, which are compared between organic and conventional rice farmers. The result provides government agencies an outline of how to increase organic farming, especially for smallholder farmers, and the long-term benefits will decrease poisonous contamination and increase human health.

Exposure to Pesticides and Health Effects on Farm Owners and Workers From Conventional and Organic Agricultural Farms in Costa Rica: Protocol for a Cross-Sectional Study

Background

Pesticide use is increasing in low- and middle-income countries (LMICs) including Costa Rica. This increase poses health risks to farm owners, farm workers, and communities living near agricultural farms.

Objective

We aimed to examine the health effects associated with occupational pesticide exposure in farm owners and workers from conventional and organic smallholder farms in Costa Rica.

Methods

We conducted a cross-sectional study involving 300 owners and workers from organic and conventional horticultural smallholder farms in Zarcero County, Costa Rica. During the baseline study visit, we administered a structured, tablet-based questionnaire to collect data on sociodemographic characteristics, pesticide exposure, and health conditions (eg, respiratory and allergic outcomes and acute pesticide intoxication symptoms) and administered a neurobehavioral test battery (eg, Finger Tapping Test and Purdue Pegboard); we measured blood pressure, anthropometry (height, weight, and waist circumference), and erythrocytic acetylcholinesterase activity and also collected urine samples. In addition, a functional neuroimaging assessment using near-infrared spectroscopy was conducted with a subset of 50 study participants. During the follow-up study visit (~2-4 weeks after the baseline), we administered participants a short questionnaire on recent pesticide exposure and farming practices and collected hair, toenail, and urine samples. Urine samples will be analyzed for various pesticide metabolites, whereas toenails and hair will be analyzed for manganese (Mn), a biomarker of exposure to Mn-containing fungicides. Self-reported pesticide exposure data will be used to develop exposure intensity scores using an exposure algorithm. Furthermore, exposure-outcome associations will be examined using linear and logistic mixed-effects regression models.

Results

Fieldwork for our study was conducted between May 2016 and August 2016. In total, 113 farm owners and 187 workers from 9 organic and 83 conventional horticultural smallholder farms were enrolled. Data analyses are ongoing and expected to be published between 2019 and 2020.

Conclusions

This study is one of the first to examine differences in health effects due to pesticide exposure between farm owners and workers from organic and conventional smallholder farms in an LMIC. We expect that this study will provide critical data on farming practices, exposure pathways, and how occupational exposure to pesticides may affect farm owners and workers’ health. Finally, we hope that this study will allow us to identify strategies to reduce pesticide exposure in farm owners and workers and will potentially lay the groundwork for a future longitudinal study of health outcomes in farm owners and workers exposed to pesticides.

International Registered Report Identifier (IRRID)

DERR1-10.2196/10914

Markers of genotoxicity and oxidative stress in farmers exposed to pesticides

The effects of chronic exposure to pesticides can lead to the development of several diseases, including different types of cancer, since the genotoxic and mutagenic capacity of these substances can be observed. The objective of this study is to investigate the relation between the occupational exposure to various pesticides and the presence of DNA damage and oxidative stress. Blood samples from 50 rural workers (41 men and 9 women) exposed to pesticides, 46 controls (20 men and 26 women) from the same city (Antônio Carlos, Santa Catarina state, Brazil) and 29 controls (15 men and 14 women) from another city (Florianópolis, Santa Catarina state, Brazil), were evaluated using the comet assay and the cytokinesis-block micronucleus (CBMN) technique for genetic damage, and the test of thiobarbituric acid reactive substances (TBARS) and catalase (CAT) activity for the oxidative stress. Cholinesterase activities were also determined, but there was no statistical difference among exposed workers and controls. Significant differences were found in DNA damage among groups. The comet assay performed on peripheral blood lymphocytes of these individuals had a significantly higher DNA damage index in the exposed group comparing to controls (p < 0.0001). MNi (p < 0.001), NBUDs (p < 0.005) and NPBs (p < 0.0001) were also found to be significantly higher in the exposed group. The TBARS values were significantly higher comparing to the Florianopolis control group (p < 0.0001). Even though CAT values were higher than controls, there was no statistical difference. Thus, it is concluded that the exposed individuals, participants of this study, are more subject to suffer genetic damage and, consequently, more susceptible to diseases resulting from such damages.

Pyrethroid epidemiology: a quality-based review

Pyrethroids are commonly used around the home and in agricultural production to control insects. Human contact to one or more pyrethroid insecticides is likely. Numerous epidemiology studies have evaluated the association between health outcomes in humans and pyrethroid exposure. The purpose of this review was to identify and evaluate the quality of pyrethroid-related epidemiology studies that addressed chronic health effects, and compare findings with animal toxicology studies. We evaluated the quality of 61 studies published between 2000 and 2016 by using elements of outcome, exposure metric, exposure level, and study design. None of the 61 publications demonstrated strong quality for all elements. A few of the outcome measures were strong, particularly those relying upon medical diagnoses. Most of the pyrethroid epidemiology studies used a poor exposure metric, relying upon a single sample of pyrethroid urinary metabolites, which is subject to misclassification of past exposures. In addition, many studies were a cross-sectional design, preventing an evaluation of the temporality of the exposure-disease association. Furthermore, none of the effects observed in the epidemiological literature was concordant with toxicological effects noted in extensive testing of pyrethroids in animals. In order to provide more robust data on potential health outcomes from low dose exposure to pyrethroid insecticides, future epidemiological studies should fully characterize an adverse outcome, include exposure validation components, and quantify exposure over time.

How does exposure to pesticides vary in space and time for residents living near to treated orchards?

This study investigated changes over 25 years (1987-2012) in pesticide usage in orchards in England and Wales and associated changes to exposure and risk for resident pregnant women living 100 and 1000 m downwind of treated areas. A model was developed to estimate aggregated daily exposure to pesticides via inhaled vapour and indirect dermal contact with contaminated ground, whilst risk was expressed as a hazard quotient (HQ) based on estimated exposure and the no observed (adverse) effect level for reproductive and developmental effects. Results show the largest changes occurred between 1987 and 1996 with total pesticide usage reduced by ca. 25%, exposure per unit of pesticide applied slightly increased, and a reduction in risk per unit exposure by factors of 1.3 to 3. Thereafter, there were no consistent changes in use between 1996 and 2012, with an increase in number of applications to each crop balanced by a decrease in average application rate. Exposure per unit of pesticide applied decreased consistently over this period such that values in 2012 for this metric were 48-65% of those in 1987, and there were further smaller decreases in risk per unit exposure. All aggregated hazard quotients were two to three orders of magnitude smaller than one, despite the inherent simplifications of assuming co-occurrence of exposure to all pesticides and additivity of effects. Hazard quotients at 1000 m were 5 to 16 times smaller than those at 100 m. There were clear signals of the impact of regulatory intervention in improving the fate and hazard profiles of pesticides used in orchards in England and Wales over the period investigated.

Organic food and the impact on human health

In the last decade, the production and consumption of organic food have increased steadily worldwide, despite the lower productivity of organic crops. Indeed, the population attributes healthier properties to organic food. Although scientific evidence is still scarce, organic agriculture seems to contribute to maintaining an optimal health status and decreases the risk of developing chronic diseases. This may be due to the higher content of bioactive compounds and lower content of unhealthy substances such as cadmium and synthetic fertilizers and pesticides in organic foods of plant origin compared to conventional agricultural products. Thus, large long-term intervention studies are needed to determine whether an organic diet is healthier than a diet including conventionally grown food products. This review provides an update of the present knowledge of the impact of an organic versus a conventional food diet on health.

Different end-points to assess effects in systemic lupus erythematosus patients exposed to pesticide mixtures

Systemic Lupus Erythematosus (SLE) is an autoimmune disease with high female predominance in reproductive years. It is characterized by a pronounced inflammation and production of a variety of autoantibodies. SLE pathogenesis is influenced by genes, hormones and environmental agents. The aim of this study was assess the possible effect of environmental pesticide mixtures in SLE patients. Oxidative DNA damage was measured using the comet assay modified by enzyme Endo III for detection of oxidized bases (Endo Sites), and oxidative stress by the measurement of the activity of catalase (CAT), superoxide dismutase (SOD) and lipid peroxidation (TBARS). Eighty-nine patients with diagnosis of SLE were included, 46% of them came from areas highly sprayed with pesticides and were compared with patients from urban areas with the same clinical and socio-demographic characteristics (p≥0.155). In order to identify factors that could predict DNA damage and oxidative stress, a binary logistic regression model with independent variables was developed: place of residence (p=0.007) have 75% of positive predictive value while smoking habit (p=0.186) have a 56% negative predictive value. The Odd Ratio (OR) obtained indicate that lupus patients living in rural areas presented 3.52 times more oxidative DNA damage compared to those living in the city. The prospects of applying biomarkers to assess exposure and biological effects, such as DNA damage and oxidative stress in autoimmune diseases, allow improving the characterization of individual risk.

The use of the lymphocyte cytokinesis-block micronucleus assay for monitoring pesticide-exposed populations

Pesticides are widely used around the world, and hundreds of millions of people are exposed annually in occupational and environmental settings. Numerous studies have demonstrated relationships between pesticide exposure and increased risk of cancers, neurodegenerative and neurodevelopmental disorders, respiratory diseases and diabetes. Assessment of genotoxicity of pesticides and biomonitoring their effect in exposed populations is critical for a better regulation and protection, but it can be complicated because pesticides are often used as complex mixtures. The cytokinesis-block micronucleus assay in human lymphocytes (L-CBMN) is a validated method of assessment of DNA damage induced by clastogenic and aneuploidogenic mechanisms. The goal of this review is to provide an updated summary of publications on biomonitoring studies using this assay in people exposed to pesticides in different settings, and to identify gaps in knowledge, and future directions. A literature search was conducted through MedLine/PubMed and TOXLINE electronic databases up to December 2015. A total of 55 full-text articles, related to 49 studies, excluding reviews, were selected for in depth analysis, divided by the settings where exposures occurred, such as chemical plant workers, pesticide sprayers, floriculturists, agricultural workers and non-occupationally exposed groups. Majority of studies (36 out of 49) reported positive findings with L-CBMN assay. However, most of the studies of professional applicators that used single pesticide or few compounds in the framework of specific programs did not show significant increases in MN frequency. A decreased level of pesticide-induced genotoxicity was associated with the proper use of personal protection. In contrast, subjects working in greenhouses or during intensive spraying season and having acute exposure, showed consistent increases in MN frequency. Overall, this analysis confirmed that L-CBMN is an excellent tool for pesticide biomonitoring, and can validate the effects of educational and intervention programs on reducing exposure and genetic damage.