Agricultural Pesticide Applications Research Articles

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.

Environmental Impacts of Pesticides - A Review

Pesticides are applied in various sectors such as agriculture, domestic, material building, personal and public health for control of weeds, pests, rodents; household and garden spray, control of animals and birds; incorporation of paints, glues, plastic protection sheeting; for application of clothing and skincare; and for control of malaria, dengue fever and cholera. In agriculture, chemicals are purposefully discharged into the environment. Application of pesticides in agriculture is a subcategory of the largest group of manufactured compounds used in the present world. Excessive and inappropriate use of pesticides has resulted in contamination of environment. Pesticides are degraded into organic micro pollutants that have negative effects on the environment. By the mechanism of biomagnification and bioconcentration, they cause deleterious effects on the living organisms. Ecological impacts of pesticides are different but they are chronic and inter-related. During precipitation, pesticides from land, float to aquatic systems and become harmful to fishes, birds, non-target creatures, etc. They also interact with injurious algal blooms, which enhances the original poisonous nature of the pesticides. This review focuses on environmental impacts of pesticides on contamination of water, fate, effects and behaviour in the environment, effects of contamination on natural resources, food safety, non-target organisms and threats to biodiversity. This study recommends application of suitable amounts of less harmful formulation of pesticides, as and when required.

Drvenaste biljke u fitoremedijaciji zagađenja poljoprivrednog zemljišta nitratima i pesticidima

Although plants have a natural potential for removing various types of pollutants from nature, phytoremediation is a relatively new area of research and has a commercial application. By intensive application of nitrogen fertilisers and pesticides in agriculture, their excessive amounts reach the soil and accumulate or flow into deeper layers of soil and groundwater. So far, most soil remediation studies have been done with herbaceous plants, but they have not shown high efficiency. The paper gives an overview of the possibilities and advantages of using woody plants in the phytoremediation of soils contaminated with nitrates and pesticides. The choice of woody species that can be successfully applied is limited and the best results were obtained with poplars and willows. Unlike nitrates, which are easily absorbed by trees, pesticides are complex organic compounds and their remediation takes place through mechanisms such as rhizodegradation and phytodegradation. Poplar, as the most commonly used woody species for phytoremediation, has shown high efficiency in removing nitrates and pesticides, especially herbicides. Examples of successful soil and groundwater remediation can be found in the remediation of atrazine, alachlor, metribuzin, paraquat and others.

Accounting and red uction path of carbon emission firom facility agriculture in China.

Facility agriculture, a typical agricultural production management mode, could affect carbon cycle due to its unique production environmental conditions and highly intensive utilization. With the five main sources as accounting objects, including agricultural film investment, energy consumption, pesticide and fertilizer application, CO2 fertilizer application, and facility soil, we estimated the amount and intensity of carbon emission of three facility agriculture (continuous greenhouse, solar greenhouse, and plastic greenhouse) in 31 provinces in 2018. The results showed that the total carbon emission of facility agriculture in China was 210.3817 million t CO2e, with the three facility agriculture types of plastic greenhouse, solar greenhouse, and continuous greenhouse accounting for 60.2%, 37.4% and 2.4%, respectively. Carbon emission of facility agriculture was mainly contributed by soil greenhouse gas, agricultural film and supplies investment. Carbon emission per unit area of continuous greenhouses was significantly lower than that of solar and plastic greenhouses. The scientific capital allocation rate and facility agriculture scale were the two main factors influencing the carbon emission in facility agriculture. Based on all the results, we presented the carbon emission reduction path from the three perspectives of improving the scientific investment, material consumption utilization rate, and facility area utilization rate of facility agriculture.

Pesticide effects on nitrogen cycle related microbial functions and community composition

The extensive application of pesticides in agriculture raises concerns about their potential negative impact on soil microorganisms, being the key drivers of nutrient cycling. Most studies have investigated the effect of a single pesticide on a nutrient cycling in single soil type. We, for the first time, investigated the effect of 20 commercial pesticides with different mode of actions, applied at their recommended dose and five times their recommended dose, on nitrogen (N) microbial cycling in three different agricultural soils from southern Australian. Functional effects were determined by measuring soil enzymatic activities of β-1,4-N-acetyliglucosaminidase (NAG) and l-leucine aminopeptidase (LAP), potential nitrification (PN), and the abundance of functional genes involved in N cycling (amoA and nifH). Effects on nitrifiers diversity were determined with amplicon sequencing. Overall, the pesticides effect on N microbial cycling was dose-independent and soil specific. The fungicides flutriafol and azoxystrobin, the herbicide chlorsulfuron and the insecticide fipronil induced a significant reduction in PN and β-1,4-N-acetylglucosaminidase activity (P < 0.05) (NAG) in the alkaline loam soil with low organic carbon content i.e. a soil with properties which typically favors pesticide bioavailability and therefore potential toxicity. For the nitrifier community, the greatest pesticide effects were on the most dominant Nitrososphaeraceae (ammonia-oxidizing archaea; AOA) whose abundance increased significantly compared to the less dominant AOA and other nitrifiers. The inhibiting effects were more evident in the soil samples treated with fungicides. By testing multiple pesticides in a single study, our findings provide crucial information that can be used for pesticide hazard assessment.

Biocontrol potential of Pseudomonas stutzeri endophyte from Withania somnifera (Ashwagandha) seed extract against pathogenic Fusarium oxysporum and Rhizoctonia solani

Agricultural crops are susceptible to abiotic and biotic factors. Among biotic factors, plant pathogens attacks are prominent and significantly reduce the crop productivity and production. Long term application of synthetic pesticides in agriculture not only causes resistance development in pathogens but also deteriorates the soil quality and pollutes the ecosystem. In the current study, an investigation has been made with an objective to isolate an endophytic bacterium from Withania somnifera seed and evaluate its potential biocontrol activity against soil-borne pathogens like Fusarium oxysporum var. ciceri and Rhizoctonia solani. The molecular approach of bacterium identification using 16S rRNA sequencing methods includes kit based DNA extraction and PCR amplification and the isolated endophytic bacterium was identified as Pseudomonas stutzeri. In dual culture assay, the endophytic bacterium P. stutzeri PSIISS-1 effectively suppressed growth of pathogenic fungi F. oxysporum var. ciceri (61.0%) and R. solani (53.3%), respectively. In vivo studies were conducted with initial microbial inoculum size of 108cell/ml and the studies revealed that the bacterium P. stutzeri PSIISS-1 co-inoculated with R. solani had significantly inhibited the sheath blight disease with the efficacy of 76% in susceptible paddy MTU-7029. Simultaneously, co-inoculation of P. stutzeri PSIISS-1 along with the pathogen F. oxysporum var. ciceri in chickpea JG-14 variety resulted in reduction of wilt symptom up to 80.45%. Bacterial inhibitions against the pathogens were corroborated with chitinase, protease and lipase enzymatic activities. Based on the results obtained from the study, P. stutzeri showed biocontrol activity against plant pathogens which can be used as potential bio-pesticides.

Residential Proximity and Cumulative Risk Assessment of Agricultural Pesticide Applications in California

BACKGROUND AND AIM: Pesticide exposure based on residential proximity to agricultural applications has been associated with adverse health outcomes including developmental neurotoxicity such as reduced IQ and autism spectrum disorder, adverse birth outcomes such as low birth weight and birth defects as well as increased risk of cancer. However, epidemiological studies have primarily assessed individual pesticides or groups of pesticides sharing a common mechanism of action. In reality, individuals living near agricultural pesticide applications are exposed to a complex mixture of pesticides impacting a broad range of potential health harms. Here we develop a toxicity index for pesticide mixtures based on multiple chronic toxicity endpoints, and identify residential areas at greatest risk of adverse health outcomes due to pesticide exposure. METHODS: Data for pesticide applications were downloaded from the California Pesticide Use Reporting program (PUR). Over 400 active ingredients were assessed for chronic toxicity endpoints including carcinogenicity, neurotoxicity, endocrine disruption, thyroid toxicity and respiratory toxicity based on classifications from authoritative bodies including the EPA, IARC, and EFSA. We developed a toxicity index for each active ingredient based on the severity of the health outcome, the strength of the association, the reliability of the data source and the NOAEL if available. We then combined the toxicity index with application rates for all pesticides applied within a square mile. RESULTS:Pesticides with the greatest toxicity index include active ingredients previously associated with adverse health outcomes including organophosphates and carbamates. Other pesticides with high toxicity indices include neonicotinoids, pyrethroids and triazole fungicides. Residential areas of high risk of potential adverse health effects due to pesticide exposure from nearby agricultural applications were identified. CONCLUSIONS:Using the pesticide toxicity index and application rates in combination with residential proximity agricultural applications can help identify and prioritize high risk areas for future pesticide policy actions to best protect public health. KEYWORDS: pesticides, cumulative risk assessment, residential proximity

Leaching of 1,2,4-triazole from commercial barley seeds coated with tebuconazole and prothioconazole

Seed dressing with fungicide or insecticide is a standard procedure for growing major crops, but very little is known about the leaching risk and the general fate of pesticides from coated seeds. Triazole fungicides are commonly used seed dressing fungicides and recently, there has been increasing concern that 1,2,4-triazole, a major degradation product of several triazole fungicides, may leach to groundwater in concentrations exceeding the 0.1 μg/L threshold limit of the European Union. We therefore carried out a laboratory column experiment with commercial barley seeds coated with the triazole fungicides tebuconazole and prothioconazole to study the fate of the fungicides and their degradation products, especially 1,2,4-triazole. Our experiment showed that the fungicides themselves were relatively immobile in the soil columns, but also that leaching of 1,2,4-triazole will occur no matter if tebuconazole or prothioconazole is used as seed dressing. Relatively high 1,2,4-triazole concentrations (up to 0.8 μg/L) were measured in the column leachates, but when the experiment was terminated after 63 days, a total of only 1 % of the fungicides was recovered as 1,2,4-triazole in the leachate. Our results suggest that seed dressing pesticides should be considered together with spray applications when estimating the total 1,2,4-triazole load from agriculture and that seed dressing pesticides and their degradation products should be included when evaluating leaching risks from pesticide applications in agriculture.

Future of Insecticide Seed Treatment

Seed treatment as a method of local application of pesticides in precise agriculture reduces the amount of pesticides used per unit area and is considered to be the safest, cheapest and most ecologically acceptable method of protecting seeds and young plants from pests in the early stages of their development. With the introduction of insecticides from the neonicotinoid group in the mid-1990s, the frequency of seed treatment increased. Due to suspected negative effects on pollinators, most of these insecticides are banned in the European Union. The ban has therefore led to a reduction in the number of active substances approved for seed treatment and to an increased re-use of active substances from the group of pyrethroids as well as other organophosphorus insecticides, which pose potentially very serious risks, perhaps even greater than those of the banned neonicotinoids. The objective of this review is to analyze the advantages and disadvantages of seed treatment and the potential role of insecticide seed treatment in reducing the negative impact of pesticides on the environment. The main disadvantage of this method is that it has been widely accepted and has become a prophylactic protective measure applied to almost all fields. This is contrary to the principles of integrated pest management and leads to an increased input of insecticides into the environment, by treating a larger number of hectares with a lower amount of active ingredient, and a negative impact on beneficial entomofauna. In addition, studies show that due to the prophylactic approach, the economic and technical justification of this method is often questionable. Extremely important for a quality implementation are the correct processing and implementation of the treatment procedure as well as the selection of appropriate insecticides, which have proven to be problematic in the case of neonicotinoids. The ban on neonicotinoids and the withdrawal of seed treatments in oilseed rape and sugar beet has led to increased problems with a range of pests affecting these crops at an early stage of growth. The results of the present studies indicate good efficacy of active ingredients belonging to the group of anthranilic diamides, cyantraniliprole and chlorantraniliprole in the treatment of maize, soybean, sugar beet and rice seeds on pests of the above-ground part of the plant, but not on wireworms. Good efficacy in controlling wireworms in maize is shown by an insecticide in the naturalites group, spinosad, but it is currently used to treat seeds of vegetable crops, mainly onions, to control onion flies and flies on other vegetable crops. Seed treatment as a method only fits in with the principles of integrated pest management when treated seeds are sown on land where there is a positive prognosis for pest infestation.

Rapid detection of diazinon as an organophosphorus poison in real samples using fluorescence carbon dots

Due to the growing population of the world and the concerns related to food security, the application of pesticides in agriculture has increased in order to increasing the production efficacy. Excessive use of such chemicals can lead to serious contaminations in environmental and food chains. In this way, it is necessary to find more accurate and fast approaches to the detection of pesticide residuos in food. In this paper, a simple, rapid and inexpensive nanosensor based on fluorescence carbon dots (CDs) has been reported for the detection of diazinon on real samples. The synthesized CDs were characterized using UV–vis and fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive x-ray spectroscopy (EDX). The obtained CDs showed maximum fluorescence emission at 485 nm when excited at 393 nm. Upon the addition of diazinon, the emission was quenched accordingly with a concentration-dependent manner. The designed nanosensor could specifically detect diazinon in comparison to other organophosphorus poisons. The sensor has achieved a limit of detection (LOD) of 0.038 ± 0.01 µM and a dynamic linear range of up to 13 µM.

Residential proximity to pesticide application as a risk factor for childhood central nervous system tumors

BackgroundPesticide exposures have been examined previously as risk factors for childhood brain cancers, but few studies were able to assess risk from specific agents. ObjectiveTo evaluate risks for childhood central nervous system tumors associated with residential proximity to agricultural pesticide applications. MethodsUsing the California Cancer Registry, we identified cancer cases less than 6 years of age and frequency matched them by year of birth to 20 cancer-free controls identified from birth certificates. We restricted analyses to mothers living in rural areas and births occurring between 1998 and 2011, resulting in 667 cases of childhood central nervous system tumors and 123,158 controls. Possible carcinogens were selected per the Environmental Protection Agency's (US. EPA) classifications, and prenatal exposure was assessed according to pesticides reported by the California Department of Pesticide Regulation's (CDPR) Pesticide Use Reporting (PUR) system as being applied within 4000m of the maternal residence at birth. We computed odds ratios for individual pesticide associations using unconditional logistic and hierarchical regression models. ResultsWe observed elevated risks in the hierarchical models for diffuse astrocytoma with exposure to bromacil (OR: 2.12, 95% CI: 1.13–3.97), thiophanate-methyl (OR: 1.64, 95% CI: 1.02–2.66), triforine (OR: 2.38, 95% CI: 1.44–3.92), and kresoxim methyl (OR: 2.09, 95% CI: 1.03–4.21); elevated risks for medulloblastoma with exposure to chlorothalonil (OR: 1.78, 95% CI: 1.15–2.76), propiconazole (OR: 1.60, 95% CI: 1.02, 2.53), dimethoate (OR: 1.60, 95% CI: 1.06, 2.43), and linuron (OR: 2.52, 95% CI: 1.25, 5.11); and elevated risk for ependymoma with exposure to thiophanate-methyl (OR: 1.72, 95% CI: 1.10–2.68). ConclusionOur study suggests that exposure to certain pesticides through residential proximity to agricultural applications during pregnancy may increase the risk of childhood central nervous system tumors.

Using Soft Sensors as a Basis of an Innovative Architecture for Operation Planning and Quality Evaluation in Agricultural Sprayers

One of the major problems facing humanity in the coming decades is the production of food on a large scale. The production of large quantities of food must be conducted in a sustainable and responsible manner for nature and humans. In this sense, the appropriate application of agricultural pesticides plays a fundamental role since pesticide application in a qualified manner reduces human and environmental risks as well as the costs of food production. Evaluation of the quality of application using sprayers is an important issue, and several quality descriptors related to the average diameter and distribution of droplets are used. This paper describes the construction of a data-driven soft sensor using the parametric principal component regression (PCR) method based on principal component analysis (PCA), which works in two configurations: with the input being the operating conditions of the agricultural boom sprayers and its outputs being the prediction of the quality descriptors of spraying, and vice versa. The soft sensor provides, in one configuration, estimates of the quality of pesticide application at a certain time and, in the other, estimates of the appropriate sprayer-operating conditions, which can be used for control and optimization of the processes in pesticide application. Full cone nozzles are used to illustrate a practical application as well as to validate the usefulness of the soft sensor designed with the PCR method. The selection of historical data, exploration, and filtering of data, and the structure and validation of the soft sensor are presented. For comparison purposes, the results with the well-known nonparametric k-Nearest Neighbor (NN) regression method are presented. The results of this research reveal the usefulness of soft sensors in the application of agricultural pesticides and as a knowledge base to assist in agricultural decision-making.

Ambient Pyrethroid Pesticide Exposures in Adult Life and Depression in Older Residents of California's Central Valley.

Pyrethroid pesticide exposures may be associated with the onset of depression in later life via disruption of dopaminergic, serotonergic, and neurological functioning. We sought to investigate the association between living near agricultural pyrethroid pesticide applications and depression measures in central California, using two waves (PEG 1&2, total N = 1,654) of a case control study of Parkinson’s disease (PD). At enrollment, participants self-reported history of use of depression medications and dates of MD-diagnosed depression and anxiety. Participants also completed a Geriatric Depression Scale-Short Form upon enrollment. We used the California Pesticide Use Registry to assign estimated ambient pyrethroid pesticide exposures at participant’s home addresses over the 5 years before the index date (date of outcome, or an age-matched year for participants without the outcome). We used logistic and linear regression to evaluate associations between living near any pyrethroid applications over the 5-year index period and measures of depression and anxiety. We also evaluated modification by study wave and PD status. We observed associations of pyrethroids with depression, depression medications, and anxiety (adjusted odds ratio [aOR] depression = 1.54, 95% confidence interval [CI] 1.14, 2.07; aOR depression medications = 1.68, 95% CI 1.25, 2.25; aOR anxiety = 1.60, 95% CI 1.17, 2.18). However, we observed no associations with mild/moderate depressive symptoms according to the GDS score at enrollment (aOR = 1.04, 95% CI 0.77, 1.42). We did not observe a consistent modification of the pyrethroid-depression associations by study wave and PD status. Ambient pyrethroid pesticide exposures may be associated with measures of depression in later life.