Agricultural Pesticide Applications Research Articles

Spraying performance and deposition characteristics of an improved air-assisted nozzle with induction charging.

Electrostatic spraying technology can improve the efficiency of pesticide deposition on the surface of leaves and reduce the environmental pollution caused by pesticide drift, which has an important prospect in agricultural pesticide application. To improve the deposition and penetration of droplets in the crop canopy, we designed and optimized an air-assisted electrostatic nozzle and conducted the spraying performance experiment. Parameters, such as charge-to-mass ratio (CMR) and particle size, were tested and analyzed to obtain the suitable operating parameters of nozzle. The results proved that the improved air-assisted electrostatic nozzle has good atomization and chargeability. There is a good charging effect with a charging voltage of 3,000-5,000 V, the CMR increased 127.8% from 0.86 to 1.97 mC/kg as the charge voltage increases from 1,000 to 4,000 V, at an air pressure of 1.0bar and liquid flow rate of 200 ml/min. Furthermore, we designed a multi-factor orthogonal experiment, which was conducted using a four-factor, three-level design to investigate the effects of operational parameters and canopy characteristics on droplet deposition and penetration. Analysis of variance (ANOVA) and F-test were performed on the experiment results. The results showed that the factor effect on droplet penetration, in descending order, was as follows: spray distance, leaf area index, air pressure, and air pressure × spray distance. The factor effect on abaxial leaf deposition, in descending order, was as follows: air pressure, spray distance, air pressure × charge voltage, spray distance × charge voltage, and charge voltage. For optimal droplet penetration and abaxial leaf deposition, option A 3 B 1 D 2 (air pressure 1.5bar, spray distance 0.2m, charge voltage 2,500 V) is recommend. The spray nozzle atomization performance and deposition regulation were studied by experimental methods to determine the optimal values of operating parameters to provide a reference for electrostatic spray system development.

Pesticide contamination pattern from Morocco, insights into the surveillance situation and health risk assessment: a review.

The widespread application of pesticides in Morocco's agriculture renders their monitoring in food and environmental samples very necessary. Recent years have witnessed a growing interest in reporting studies related to the monitoring of pesticide residues in food, water, groundwater, and soil as well as their quantitative health risk assessment. Most published studies have been done by university researchers. However, the lack of research reproducibility remains a problem that considerably limits the possibility of exploiting data from the literature. Our study involves an extensive literature review utilizing search engines with keywords like "pesticide residues," "monitoring," "vegetables and fruits," "water and soil," "risk assessment," and "Morocco" from 2009 to 2023. Analysis of pesticide residues in foodstuffs and environmental samples highlights concerns over compliance with EU regulations, the health risks associated with pesticide exposure, and the necessity for comprehensive monitoring and risk assessment strategies. This paper could help influence policies to develop a strategy and action plan for the sound management of pesticides, including measures to reduce their use, raise awareness, and monitor compliance. Also, this paper could be useful for scientists interested in understanding the current situation and challenges regarding pesticide residues in Morocco, as well as countries with which commercial links exist.

FAKTOR-FAKTOR YANG BERHUBUNGAN DENGAN KEJADIAN HIPERTENSI PADA PETANI PADI DI DESA PRAJEGAN KECAMATAN SUKOREJO KABUPATEN PONOROGO

The application of pesticides in agriculture can have an impact in environmental quality and cause health problems for farmers. Prajegan Village is one of the villages that uses a large amount of pesticides and the highest cases of hypertension in Sukorejo District. The aimed of this study was to find out the factors related to the incidence of hypertension among paddy farmers in Prajegan Village, Sukorejo District, Ponorogo Regency. This type of study was analytic observational with a cross-sectional design. The total population in the research was 718 paddy farmers. The sample in this study was 97 paddy farmers who was taken by purposive sampling. The data were collected using a questionnaire and sphygmomanometer. The results showed that as many 58 farmers (59.8%) had hypertension, low education level was found in 67 farmers (69.1%), working period >5 years was found in 81 farmers (83.5%), inappropriate pesticide doses were found in 57 farmers (58.8%), risky spraying time was found in 13 farmers (13.4%), the average spraying frequency of 1x/week was found in 66 farmers (68%), and the use of PPE <5 was found in 57 farmers (58.8%). Chi-square test results showed that there is correlation between education level (p= 0.047), working period (p= 0.023), pesticide doses (p = 0.002), the use of PPE (p= 0.023), and there is no correlation between spraying time (p= 0.439) and spraying frequency (p= 1.000). From this study, it can be concluded that the factors related to the incidence of hypertension are education level, working period, pesticide doses, and the use of PPE.

Advanced embedded generalized predictive controller based on fuzzy gain scheduling for agricultural sprayers with dead zone nonlinearities

Variable rate application of pesticides in agriculture can improve pest control and also increase food production. Nevertheless, incorrect spraying poses risks to the environment and human health, as well as may increase the total cost of production. Nowadays, it is quite known the importance of innovation in techniques and technologies to improve the spraying process in a variable rate application for pest control. This work presents a generalized predictive control (GPC) strategy to cope with nonlinearities. An extension of the stability analysis for constrained GPC controller for infinite horizons is also developed, which guarantees the stability of a fuzzy GPC for a limited variation of its tuning parameters λ and δ. Results show the usefulness in adding a fuzzy logic system, to cope with nonlinearities, leading to a conception of an advanced fuzzy GPC for a limited variation of its tuning parameters.

Atmospheric Transport of Adulticides Used to Control Mosquito Populations across an Urban Metropolitan Area

Pesticides registered with the U.S. EPA for mosquito control are called adulticides and are released directly into the atmosphere as aerosols to target flying mosquitos. This adulticide application approach is different from traditional (agricultural) pesticide applications, yet the fate and transport of adulticides in large metropolitan areas is largely unknown. The Houston Metropolitan Area encompasses eight counties, many of which require county-level mosquito control programs that utilize adulticides. Malathion and permethrin are the primary adulticides used by Harris County (HC) in Houston, TX, USA. Houston, like many other metropolitan areas, has an urban atmosphere supporting the oxidation of both gas and particle phase pollutants. During the summer mosquito season of 2016, we collected atmospheric total suspended particulate matter (PM) samples at Jones Forest (JF), located in Montgomery County (directly north of HC) to investigate the atmospheric transport and oxidation of adulticides in an urban atmosphere. Despite HC alternating the adulticide treatment schedule, we measured permethrin, malathion, and malaoxon (oxidation product of malathion), throughout the sampling campaign. These consistent measurements, in conjunction with 12 h backward trajectories, support the conclusion that JF is influenced by other county-level mosquito-control programs and agricultural pesticide use. This cross-county transport may impact adulticide effectiveness by supporting pesticide resistance in mosquito populations due to repeated exposures to pesticides. This study highlights the need for mosquito control collaborations between counties, especially in areas of urban expansion overlapping with agricultural activities.

Responses of soil bacterial and fungal denitrification and associated N2O emissions to organochloride pesticide

The extensive application of organochloride pesticides in agriculture has raised concerns about their potential negative impacts on soil microbial denitrification and associated N2O emissions. However, most studies have primarily focused on bacteria, and the contribution of fungi to N2O emissions and their response to organochloride pesticides have often been overlooked. In this study, 15N tracing combined with the respiration inhibition method was applied to examine the impacts of chlorothalonil on both fungal and bacterial denitrification. The results demonstrated that fungal N2O emissions dominated in the absence of chlorothalonil, accounting for 73 % of total N2O emissions. Chlorothalonil inhibited fungal and bacterial denitrification via different mechanisms and altered the main pathways of soil N2O emissions. Amplicon sequencing analyses indicated that chlorothalonil significantly reduced the abundances of N2O-producing fungi owing to its fungicidal effect and fungal N2O emissions significantly dropped. Molecular biological analyses revealed that chlorothalonil induced lower electron generation, transport, and consumption efficiencies, which led to the inhibition of denitrifying enzymes in bacteria. Bacterial N2O emissions dramatically increased and became the dominant source. These findings provide insights into the mechanisms by which N2O emissions from fungal and bacterial denitrification are influenced by chlorothalonil.

The Biosurfactants Mannosylerythritol Lipids (MELs) as Stimulant on the Germination of Lactuca sativa L.

The application of pesticides in agriculture leads to improved crop quality and promotes high productivity. However, the uninterrupted use of these chemicals is directly related to environmental impacts, affecting biodiversity and the health of ecosystems and humans. In this sense, mannosylerythritol lipids (MELs) are a promising alternative, as they are biosurfactants with antimicrobial, amphiphilic characteristics, and low toxicity. Thus, in search of a partial reduction in the use of chemical pesticides in agriculture, this work aimed to evaluate the biostimulant effect of one of the homologs of MELs–MEL-B on the germination of Monica lettuce seeds (Lactuca sativa L.) and the influence on plant growth and root development. The seeds germinated in different concentrations of MEL-B. The incidence of germinated seeds, the germination index, and the average germination time were evaluated. MEL-B at 158 mg/L stimulated seed germination, growth, and seedling development parameters by 65%, while concentrations of 316 and 632 mg/L did not exceed 45% for these parameters. It was observed that MEL-B at 158 mg/L biostimulated the appearance of lateral roots and promoted only 7% of root stress, a difference of 47% for roots grown with MEL-B at 632 mg/L. Furthermore, MEL-B at 158 mg/L was the highest concentration at which there was no phytotoxic effect of MEL-B on seeds. The increase in enzymatic activity corroborates the phytotoxic effect and seed stress at concentrations of 316 and 632 mg/L, showing results of 47% and 54% of stressed roots. In an unprecedented way, this study proved that MEL-B has a biostimulant and phytotoxic effect related to its concentration.

Spray Characterization of an Unmanned Aerial Vehicle for Agricultural Spraying

Sustainability and higher efficiency in crop production are possible with the use of new technologies. The use of unmanned aerial vehicles (UAVs) brings many advantages, both in terms of monitoring agricultural areas and pesticide applications, and allows for early disease and damage detection as well as its application in areas without access to conventional sprayers. This study established parameters for spraying with clean water using a DJI Agras 14 MG-1P (RTK) UAV. Droplet distribution and droplet analyses were examined in the experiments carried out at different heights (1.5, 2.0, and 2.5 m) and flow rates (10, 15, 20, 25, and 30 L/ha). Droplets were analyzed using DepositScan. Coefficients of Variation of droplet distribution decreased with the increasing spray rate. The trials with the closest values to uniformity were spraying applications made at a flight height of 2.0 m. When evaluating pesticide efficacy according to the number of droplets per unit area, insecticides and all herbicides can be effective at applications at flight heights of 1.5 and 2.0 m and spray rates of 20 L/ha. While all spraying is done at flight heights of 1.5 and 2.0 m and spray rates of 25 L/ha, fungicides are ineffective when applied from a height of 2.5 m. As a result, this study found measurements made at a 2.0 m altitude and a 20 L/ha spray rate to have the highest coverage rate and the lowest drift potential.

DEVELOPMENT AND FABRICATION OF AGRICULTURAL PEST CONTROL SYSTEM

Research is “creative and systematic work undertaken to increase the stock of knowledge”. It involves the collection, organization and analysis of information to increase understanding of a topic or issue. Efficient use of pesticides can helpful to control plant pests and diseases to increasethe crop yields. The use of agrochemicals can effectively enhance the quantity and quality of crop;however, it increases the environmental risks in recent years. Pesticide application utilizes the to a significant percentage of the production cost. During chemical plant protectionpractices, over application of pesticide or inefficient spraying equipment may cause serious issueson human healthand the environment. Effective pesticide application is a critical activity during crop production season that requires efficient spraying machinery with proper calibration as well as relevant regulations to reduce off-target spray deposition. Thus, the significant among all the factors which are influencing the degree of off-target spray deposition is the design and application spraying technology Conventional agricultural pesticide application practices havedeveloped a contradiction among the yield enhancement, cost effectiveness and environmental protection. Therefore, pesticides have to be applied using suitable spraying systems to avoid adverse effects on environment as well as human health. Thus, in recent decades, spraying methods and technologieshave been undergoing continuous evolution. Conventional sprayerswere very laborious and International Journal of Scientific Research in Engineering and Management (IJSREM) Volume: 07 Issue: 01 | January - 2023 Impact Factor: 7.185 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM17568 | Page 2 requirevery heavy machinery to operating them in the field. They increasethe application amount because of no proper application method for spraying nozzles, crop foliage detection, and weather parameters. advancement in spray application technologies increase crop production and increase pesticide efficiency on weed and insects in the field. Spray loss in the form ofspray drift, weather effects, target detection, and control flow nozzles problem solved by advancedpesticide applicationtechnologies. The time-consuming problem for tank refilling is reduced withultra-low volume sprayers and fine droplet spray nozzles. With time the crop maintaining technology-advance fromweeds and pest, detection to spray application nozzles. The objective of this chapter is to highlight the attachments conceived by both electronics and mechanical components which implies for the working of agricultural spraying machine.

Determination of the Application Parameters of Spraying Drones for Crop Production in Hazelnut Orchards

Hazelnut, which has the most common cultivation area after almonds and walnuts among the shell fruits in the world, contains high levels of fat, protein, carbohydrates, various minerals and vitamins. Hazelnut has a broad growing area around the world, and Turkey accounts for 58% of world production with 776,000 tons annually. With this production capacity, Turkey ranks first in hazelnut production over the world. Harmful insects in hazelnut trees are the main factors that reduce hazelnut yield and quality. Pesticides are sprayed with backpack sprayers in the fight against these pests in hazelnut trees. Farmers are directly exposed to pesticides in these practices, which use high amounts of pesticides and water. In recent years, the use of unmanned agricultural vehicles in agriculture has increased. Drones are also used in pesticide applications in agriculture. In this study, the suitability of pesticide applications with the drone in hazelnut fields in Giresun province in terms of field conditions and spraying efficiency was investigated. In September 2021, applications were made with DJI Agras MG-1P model spraying drone in a selected hazelnut orchard in Uzgur village of Giresun province. The drone has 4 Teejet XR11001VS fan jet nozzles. Water-sensitive papers were placed on different regions on the hazelnut trees to be sprayed for drop measurements. In the experiments, hazelnut trees were sprayed using water at different heights and spraying rates. 6 flights were carried out at 1.5 and 2 meters altitudes and 1, 2 and 3 L.da-1 spray rates, and three hazel trees were sprayed as three repetitions in each flight. After the flight trials, the water-sensitive papers were scanned on the scanner, and the volume median diameters and the number of droplets per square centimetre were calculated in the DepositScan software. As a result of the analyses done, it was observed that the applications performed at 1 L.da-1 and 2 L.da-1 spray rates would not be sufficient in terms of spraying efficiency. As the drone flight altitude increased, the accumulation of the drops on the inner leaves decreased. In terms of drop distribution, the most homogeneous application parameter was found to be 1.5 meters high above the upper leaves of the hazel trees and 3 L.da-1 spray rate.

Assessing the ecological risk and ecotoxicity of the microbially mediated restoration of heavy metal-contaminated river sediment

Anthropogenic activities such as mining, smelting industries, and the application of pesticides in agriculture might result in contamination of multiple heavy metals in the environment. Heavy metal contamination of sediment is a serious environmental problem, and thus the remediation of contaminated sediment is a worldwide challenge. Several strategies have been developed for the remediation of contaminated sediment, however the ecological risk and ecotoxicity of the restored sediment have rarely been evaluated. We assessed whether river sediment highly contaminated with heavy metals could be restored using microbial bioleaching followed by evaluating the residual toxicity and ecological risk of the microbially remediated sediment. Sequential extraction revealed that the bioavailable levels of Cu, Ni, and Zn in the contaminated sediment exceeded sediment quality guideline (SQG) thresholds. It was consequently found that acidophilic sulfur-oxidizing Acidicaldus sp. SV5 effectively bioleached Cu, Ni, and Zn from the contaminated sediment, reducing the bioavailable fraction of these elements below SQG thresholds. The ecological risk assessment indicated that SV5-driven remediation significantly reduced the potential ecological risk of the contaminated sediment. The residual ecotoxicity of the microbially remediated sediment was also tested with the soil nematode Caenorhabditis elegans. There was a significant decrease in the body burden of Cu, Ni, and Zn in C. elegans and a reduction in the toxicological effect on survival, growth, and reproduction in the microbially remediated sediment. Our study suggests that a combination of chemical analysis, chemical-based ecological risk assessment, and ecotoxicity tests would be helpful for the development of efficient and eco-friendly strategies for the restoration of contaminated sediment, which could be incorporated into sediment quality management practices.

Knowledge about Pesticides Use and Consumption of Fruit and Legumes in Growers and Consumers in the Province of Nador, Morocco. Results from a Survey Study.

Introduction: Pesticides are increasingly used in agriculture to protect crops against diseases, insect pests, weeds, etc. Pesticides leave residues and chemical active material, which can affect the health of consumers. Several epidemiological studies have demonstrated a link between pesticide residues in fruits and vegetables and disease infestations in humans and problems related to sterility, allergies, and even carcinogenic diseases. Consumer awareness and the application of strict legislation about the application of pesticides in agriculture remain as a good alternative to face this issue. Methods: This survey was carried out in the region of Nador, North-East of Morocco. It is a quantitative study of a representative sample made up of 100 consumers and 50 farmers in relation to fruit and vegetables and the use of pesticides. Results: Most consumers are not aware of the danger of pesticides and residues in fruits and vegetables. In addition, the survey revealed that potato, tomato, apples, and bananas are the most consumed. These foods are usually characterized by a high rate of application of pesticides and with a higher rate of pesticides residues. In addition, surveys carried out in farmers, revealed that they consider the economic and agronomic interest of the application of these pesticides without considering the residual effects on health. Moreover, a high rate of sterility was observed among these surveyed farmers (31%). Conclusions: The consumers are less aware of the danger of pesticides. The choices of farmers are only accentuated on the aspect of economic use of these products and not on the health and environment.

7.4 Adolescent Pesticide Exposure and ADHD Risk: Mechanisms of Immediate Effect and Long-Term Vulnerability

ADHD risks in adolescents are substantial, dramatically increasing failed relationships, unemployment, and accidental injury and death as youth enter adulthood. Adolescents have substantial pesticide exposure, especially those youth employed as agricultural pesticide applicators, which are jobs they hold in many countries. Exposures in adolescent pesticide applicators to chlorpyrifos and cypermethrin have links with ADHD symptoms and related cognitive processes, acutely and persistently. No animal studies have examined pesticide exposures during adolescence for their impacts on ADHD-relevant outcomes needed to understand multiple aspects of this relationship: 1) causality; 2) the importance of individual pesticides vs their combination; 3) mechanisms playing a role in outcomes; and 4) any longer-term risk for youth.

Geographic and record-based pesticide exposure assessment, biologic exposure signatures, and chronic disease modelling in California

Background and Aims: For the past 50 years, California has been recording agricultural pesticide applications in a pesticide use reports (PUR) database; i.e. documenting use for several hundred pesticide active ingredients. These data can be employed in exposure assessment purposes targeting specific pesticides and pesticide mixtures and study a range of adverse health outcomes. Methods: In collaboration with M. Cockburn at USC, my team at UCLA has generated a geographic information system tool that uses these records in conjunction with land use data to generate spatio-temporal exposure measures for the California population living near agricultural applications. Over the past 2 decades we have used this tool kit to estimate pesticide related health effects including studies of adverse birth outcomes, autism, cerebral palsy, childhood brain cancers, Parkinson’s and Alzheimer’s disease. Results: I will present and discuss common as well as special challenges for exposure assessment and the results of the studies we conducted in the past 2 decades. Furthermore, we investigated whether long- or shorter-term exposures to agricultural use pesticides assessed with the PUR tools generate exposure signals in biological systems and bio-fluids, i.e. relying on human blood samples from older adult residents of central California to examine metabolomic patterns, methylation changes, and influences that certain pesticides have on the gut microbiome. Using integrative omics analyses, we also examined overlap between pesticide-associated biologic pathways and pathways known to be perturbed in certain diseases. Conclusions: These studies help to systematically identify physiologic responses to chronic pesticide exposures. Eventually this will help to better understand how low-level chronic pesticide exposures may contribute to chronic brain diseases in real world exposure scenarios. Keywords: pesticides, exposure assessment, Parkinson’s disease, neurodevelopment, multi-omics

Assessment of volatile organic compound emissions from pesticides in China and their contribution to ozone formation potential.

Solvents, components of pesticide emulsifiable concentrates (ECs), emit quantities of volatile organic compounds (VOCs) into the atmosphere. In the air, their active involvement in oxidative chemical reactions with oxidants exposed to ultraviolet solar radiation can result in the formation of ozone. The quantitative assessment of VOC emissions from agricultural pesticide applications remains hampered by many factors, especially the volatility coefficient of solvents in pesticides. Therefore, this study identified solvents in 20 widely used pesticide products in China. The volatility coefficients of the solvents were investigated based on a spraying test to evaluate VOC emissions from agricultural pesticide applications and their ozone formation potential (OFP). The results suggest that VOC emissions from agricultural pesticide applications amount to 0.60 Mt in 2017, with insecticides, fungicides, and herbicides contributing 0.39 Mt, 0.12 Mt, and 0.09 Mt of VOCs, respectively. Since VOC emission and maximum incremental reactivity (MIR) led to an OFP value (2.1g ozone/g product) for insecticides, a primary consideration should be to decrease use of solvents with high volatility coefficients and large MIR values in insecticide products. This work could provide valuable insights regarding response options to reduce VOC emissions and ozone formation.

Racial and social disparities in Ventura County, California related to agricultural pesticide applications and toxicity

Application of agricultural pesticides poses health concerns for farmworkers and for local communities due to pesticide drift from spraying or fumigation, pesticide volatilization into the air, contamination of household dust, as well as direct exposure for people who work in agriculture and their families. In this analysis of pesticide use records for Ventura County, California (USA) from 2016 to 2018, we identified the most prevalent toxicological effects of the pesticides applied. We also developed a cumulative toxicity index that incorporates specific toxicity endpoints for individual pesticides, the severity and strength of association for each endpoint, and the reliability of the data sources. Combining the toxicity index for each pesticide with the pounds applied within each square mile section in Ventura County, we calculated the total toxicity-weighted pesticide use and identified pesticides associated with higher potential risk to health. Analysis of U.S. Census data for Ventura County found a greater percentage of Hispanic/Latino, African American and Asian community members in township sections with a greater volume of pesticides applied and higher toxicity-weighted pesticide use. Similarly, areas with limited economic and social resources had elevated pesticide application overall and elevated toxicity-weighted pesticide use. The combination of toxicological and demographic analyses presented in this study provides information that can support the development of policies to protect public health from excessive exposure to pesticides and better environmental health protection for socially vulnerable populations.

Application of agricultural pesticides in a peak period induces an abundance decline of metazoan zooplankton in a lake ecosystem

The contamination of pesticides has been recognized as a major stressor in fresh water ecosystems in terms of the losses of services and population declines and extinctions. However, information on the adverse effects of pesticides on zooplankton communities under natural field conditions are still lacking, although zooplankton is quite sensitive to most of pesticides in laboratory studies. In this study, a natural lake ecosystem (Liangzi Lake) was used to determine the relationship between pesticide contamination and abundance decline of metazoan zooplankton. In August 2020, the comprehensive trophic level indexes and the abundance of phytoplankton in the 14 sampling sites of Liangzi Lake were comparable, but the abundance of metazoan zooplankton showed significant variations across two orders of magnitude. These results suggested that other factors, such as pesticide contamination, might be responsible for the variations of metazoan zooplankton community. Furthermore, the responsible pesticides were screened, and totally 29 pesticides were obtained. Finally, five pesticides were identified to provide more than 99.4% toxic contributions and chlorpyrifos and cypermethrin were two main causal agents. These results were further supported by laboratory exposure experiments using D. magna and field study in November 2020, where the concentrations of the 29 pesticides were strongly decreased and the abundance of metazoan zooplankton was comparable across the 14 sites of Liangzi Lake. Taken together, this work provided an evidence that the contamination of pesticides might be responsible for the abundance decline of metazoan zooplankton in a natural freshwater ecosystem.

Pesticides Exposure and Thyroid Hormone Levels Among Agricultural Workers and Pesticide Applicators: A Systematic Review

Introduction: Presently, the global consumption of pesticides including insecticides, herbicides, and fungicides to protect crops is increasing. Pesticides' role as Endocrine-Disrupting Chemicals (EDCs) has gained great concern in the field of thyroid hormones. Therefore, this systematic review aimed to determine the link of pesticide exposure with thyroid hormone levels among male agricultural workers and pesticide applicators. Discussion: It was discovered that the majority of reviewed articles have similar results concerning the effects of pesticide exposure on the serum levels of thyroid hormones among either farmworkers or pesticide applicators. Commonly, insecticides, herbicides, and fungicides are known as one of the EDCs. The results showed the elevation of TSH and T4 serum levels mostly occurred among groups exposed to insecticide application only rather than those exposed to various pesticide types. Moreover, the hormonal change differed based on each class of pesticide. Conclusion: This review suggests that some types of pesticides extensively used in agriculture might be involved in the increase and decrease in thyroid hormone levels among exposed individuals. Further studies should assess specific types of pesticides and the adverse health effects which involve confounding factors to yield robust analysis.

The effect of rising wages of agricultural labor on pesticide application in China

This paper focuses on the issue of how rising wages of agricultural labor affect pesticide application. Using survey data of 3399 rice farmers from 12 provinces in southern China between 2018 and 2019, this paper estimates the effect of wages of agricultural labor on pesticide application by employing the control function (CF) approach. The results suggest that a 10% rise in labor wages corresponds to a 6.88% increase in pesticide dosage and a 4.46% increase in pesticide expenses. Furthermore, this paper analyzes the heterogeneous effects of rising labor wages on pesticide dosage. The results reveal that the positive effect of labor wages on pesticide dosage is weaker for farmers who receive rice subsidies and have cooperative membership but it is stronger for farmers with more rice cultivation experience and those who use more chemical fertilizers. According to these findings, this study proposes policy implications for reducing pesticide application in terms of developing agricultural technologies, encouraging farmers to join cooperatives, and calling on governments to increase crop subsidies.

Application of copper(II)-based chemicals induces CH3Br and CH3Cl emissions from soil and seawater

Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are major carriers of atmospheric bromine and chlorine, respectively, which can catalyze stratospheric ozone depletion. However, in our current understanding, there are missing sources associated with these two species. Here we investigate the effect of copper(II) on CH3Br and CH3Cl production from soil, seawater and model organic compounds: catechol (benzene-1,2-diol) and guaiacol (2-methoxyphenol). We show that copper sulfate (CuSO4) enhances CH3Br and CH3Cl production from soil and seawater, and it may be further amplified in conjunction with hydrogen peroxide (H2O2) or solar radiation. This represents an abiotic production pathway of CH3Br and CH3Cl perturbed by anthropogenic application of copper(II)-based chemicals. Hence, we suggest that the widespread application of copper(II) pesticides in agriculture and the discharge of anthropogenic copper(II) to the oceans may account for part of the missing sources of CH3Br and CH3Cl, and thereby contribute to stratospheric halogen load.