The use of agrochemicals, like neonicotinoid insecticides can threaten human and environmental health when they are transported from agricultural fields. To minimize environmental impact of neonicotinoid pesticides to non-target organisms, it is important to quantify the movement of neonicotinoids from agricultural fields and examine how conventional agricultural practices can be altered using best management practices to minimize neonicotinoid transport. We developed a proportional runoff sampler that is inexpensive, rugged, and adaptable to existing runoff quantification systems. The sampler accurately collected flow-weighted samples under a broad range of steady-state and variable flow conditions. We then incorporated the sampler, along with leachate and soil sampling techniques, in a two-year field study testing the effects of winter cover crops and different edge-of-field buffer strip plant types on movement of the neonicotinoid thiamethoxam (TMX) and its metabolite clothianidin (CLO) in treated agricultural fields. Due to dry weather and other complications, runoff and leachate data could not be statistically analyzed. Soil samples indicated that cover crops had no effect on insecticide retention, so cover crops may not be a viable strategy to prevent neonicotinoid transport. Soil TMX was higher in grass buffers than native forb buffers in 2020; however, this result was not repeated in 2021 when vegetative cover was more consistent across treatments. CLO concentration did not vary by buffer in either year. Therefore, buffer strip plant type may have less impact on TMX and CLO retention than other factors like plant density. / Master of Science / Since the 1950's high yield crops and the use of pesticides and fertilizers have helped farmers increase yields from agricultural land. Increased yields have helped food production keep pace with population growth, but the use of pesticides and fertilizers can pose a threat to human and environmental health. Neonicotinoid insecticides can kill not only agricultural pests but beneficial invertebrates like bees and butterflies when the pesticides leave agricultural fields. To lessen environmental impact of neonicotinoid pesticides to the environment, it is important to understand 1) how these insecticides move from agricultural fields, and 2) how conventional agricultural practices can be altered to minimize neonicotinoid transport. We first developed a runoff sampler that was inexpensive, low maintenance, and adaptable to existing systems used to measure runoff. The sampler collects water at a rate proportional to the runoff rate under constant and changing flow rates. We then used the sampler along with leachate and soil sampling techniques in a field study testing the effect of winter cover crops and the species planted in edge-of-field vegetated buffer strips on the amount of the neonicotinoid thiamethoxam (TMX) and its degradation product clothianidin (CLO) remaining in the soil of treated fields during two growing seasons. Due to dry weather and other complications, runoff and leachate data could not be statistically analyzed. Cover crops did not change soil pesticide concentration either year, so cover crops may not be a viable strategy for preventing neonicotinoid transport. Soil TMX was higher in grass buffers than native forb buffers in 2020; however, this result was not detected in 2021 when plant growth in buffers was more uniform across treatments. CLO concentration did not vary by buffer type in either year. Therefore, the species planted in buffer strips may not be as important to holding TMX and CLO in soils as other factors like plant density.

Earth's near-surface environment sustains nearly all terrestrial life, yet this critical zone is threatened by the environmental migration of new and potentially harmful compounds produced to support a growing human population. Traditional transport equations often fail to capture the environmental behavior of these emerging contaminants due to issues such as flow heterogeneity. Thus, there is a need to better evaluate controls on pollutant partitioning in Earth's critical zone. Our first study investigated the transport and distribution of the neonicotinoid insecticide thiamethoxam (TMX) by growing TMX-coated corn seeds in coarse vs fine-textured soil columns maintained with versus without growing corn plants. Fine-textured soil transported TMX at concentrations that were two orders of magnitude higher than coarse-textured soil, due to preferential flow in the fine-textured soil columns and higher evapotranspiration (ET) concentrating more TMX in the coarse-textured soil. Living plants increased the concentration of TMX at depth, indicating that growing plants may drive preferential transport of neonicotinoids. For the second study we planted TMX-coated corn seeds and maintained field plots with and without viable crops (n = 3 plots per treatment), measuring TMX concentrations in three hydrological compartments (surface runoff, shallow lateral flow, and deep drainage) and soil. TMX was transported in the highest concentrations via surface runoff, while also showing continual migration within the subsurface throughout the growing season. Plants facilitated downward migration of TMX in soil yet restricted losses in drainage. For our final study, we used a simple isotope mixing method to evaluate how preferential flow alters the influence of compound chemical properties on solute transport. We applied deuterium-labeled rainfall to plots containing manure spiked with eight veterinary antibiotics with a range of mobility, and quantified transport to suction lysimeters (30 and 90 cm). We showed that low preferential flow (<20%) eliminates the influence of compound chemical properties and, contrary to conventional understanding, more preferential flow (~ >20%) amplifies these chemical controls, with more mobile compounds appearing in significantly higher concentrations than less mobiles ones. Altogether, we provide a refined understanding of solute partitioning in the critical zone necessary to improve process-based transport modeling. / Doctor of Philosophy / Earth’s near-surface environment sustains nearly all terrestrial life, yet this critical zone is threatened by the environmental migration of new and potentially harmful pollutants produced to support a growing human population. Additionally, traditional mathematical methods fail to accurately describe the behavior of these emerging pollutants in soils due to complex flow patterns. Thus, scientists need to better understand how these pollutants contaminate water bodies in the critical zone. We first conducted a greenhouse experiment to understand and measure the amount of the neonicotinoid insecticide thiamethoxam (TMX) that could move from coated corn seeds through the soil environment. Water draining from fine-textured soil had >100 times more TMX than water draining from course-textured soil, due to commonly occurring fractures/cracks in the finer-particle soil and more evaporation from soil and plant leaves sequestering TMX in the sandy soil. Growing plants amplified TMX movement through soil voids to lower depths. We then conducted a field study to determine how much TMX could move to the surrounding environment throughout the corn growing season. We found that plants aided in downward movement of TMX yet restricted total losses from the plot overall by removing soil water. Our third study investigated the degree to which chemical pollutant properties control movement of solutes when water flows preferentially through soil void space. Common dairy manure was spiked with eight pollutants ranging in chemical attraction to soil and was added to an agricultural field. After irrigation, we found that when total drainage water was less than 20% derived from preferential flow, chemical properties had a negligible effect on the amount of pollutant in draining soil water. Contrary to conventional understanding, when draining water contained more than 20% preferential flow, chemical properties had a strong influence on the amount of pollutant detected. Altogether, we provide new understanding of how solutes move though the critical zone. These findings are necessary to create mathematical tools that more accurately depict pollutant behavior below-ground.

L’utilisation intensive de certains pesticides et leur relative persistance vont de pair avec la présence de résidus dans l’eau de surface et l’eau potable mais aussi dans les produits agricoles disponibles pour les consommateurs, y compris les denrées alimentaires. À l’heure actuelle, les effets des pesticides sur la vie aquatique et d’autres organismes non ciblés sont relativement bien connus, et la possibilité des effets sur l’être humain fait débat. Des normes de qualité ont été proposées pour l’eau, que ce soit des critères pour l’eau potable ou des critères de protection de la vie aquatique pour l’eau de surface. Des limites maximales de résidus (MRL) de pesticides ont également été établies pour certains produits, notamment les fruits et légumes. Un des défis pour les chercheurs est la mise en œuvre de nouvelles méthodes analytiques sensibles et robustes pour la quantification ultra-trace de ces composés, afin de déterminer si les différents échantillons sont conformes aux directives ou aux MRL. L’analyse des pesticides modérément polaires dans des matrices complexes repose tout d’abord sur la méthode d’extraction. Plusieurs options sont disponibles, telles que l’extraction liquide-liquide ou en phase solide (SPE, Solid Phase Extraction) pour les matrices aqueuses, ou encore dSPE de type QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) pour les matrices solides. Actuellement, la chromatographie en phase liquide couplée à la spectrométrie de masse en tandem représente un choix pertinent pour les analyses ultra-traces, mais sa mise en œuvre peut présenter certains défis. Dans ce contexte, les principaux objectifs de ce travail de recherche sont les suivants : i) proposer des méthodes analytiques rapides, sensibles et robustes pour déterminer des pesticides multi-classes aux niveaux d’exposition que l’on retrouve dans différentes matrices comme l’eau potable, les denrées alimentaires et l’urine comme matrice biologique, et ii) évaluer le lien entre les sources de contamination des divers pesticides et leur mobilité afin de documenter la distribution spatiale et temporelle dans l’eau de surface et l’eau potable au Québec. Pour les échantillons aqueux, une méthode SPE en ligne entièrement automatisée couplée à la chromatographie liquide haute performance et spectrométrie de masse en tandem a été développée. La méthode proposée est rapide (8 min par échantillon) avec des limites de détection comprises entre 0.1 et 5 ng L-1 pour les pesticides de la famille des néonicotinoïdes et l’atrazine. Pour les produits alimentaires tels que les fruits et légumes, l’optimisation d’une méthode de type QuEChERS a été réalisée. La méthode permet d’atteindre des niveaux de détection entre 0.05 ng g-1 et 2 ng g-1 pour une gamme de 22 pesticides couvrant 7 classes différentes, incluant les organophosphorés, les carbamates, les néonicotinoïdes et les triazines, entre autres. La robustesse des diverses méthodes a été démontrée par des expériences de contrôle qualité inter- et intra-journaliers afin de garantir l’exactitude, la précision et l’absence d'effets matriciels pour de longues séquences d’analyse. Les méthodes validées ont été appliquées à des échantillons réels, y compris des échantillons d’eau du robinet couvrant 52 villes de la province du Québec (Canada), 68 échantillons d’eau de surface (fleuve Saint-Laurent et tributaires), et 133 échantillons de laitue, pomme, raisin et tomates achetés sur les marchés locaux. Les résultats indiquent une forte occurrence de l’atrazine, la thiaméthoxame, la clothianidine et l’imidaclopride dans les échantillons d’eau et les quatre produits alimentaires. / The extensive use of certain pesticides and their relative persistence go on par with the presence of residue levels in surface water and drinking water, but also in agricultural products available to consumers (including foodstuffs). There are potential effects on aquatic life and non-target organisms, and the possibility of effects in humans remains a topical issue. Quality standards have been proposed for water, including criteria for drinking water and criteria for the protection of aquatic life (surface water). Maximum residue limits (MRLs) for pesticides have also been established for foodstuff, including fruits and vegetables. One of the challenges for researchers is the implementation of sensitive and robust analytical methods for the ultra-trace quantification of these compounds, with a view to determining whether the samples are compliant with guidelines or MRLs. The analysis of moderately polar pesticides in complex matrices relies notably on the extraction method. Diverse options are available, including liquid-liquid or solid phase extraction (SPE) for aqueous samples, and dSPE approaches such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) for solid samples. Liquid chromatography coupled to tandem mass spectrometry is usually selected for separation and detection at the ultra-trace level, but there are some pitfalls. In this context, the main objectives of the present research were as follows: i) to propose fast and robust analytical methods to determine multi-class pesticides at different exposure routes including drinking water and food, and ii) to evaluate the link between the contamination sources of various pesticides and their mobility to document their distribution in surface water and tap water in Quebec. For water samples, a fully automated on-line SPE method coupled to ultra-highperformance liquid chromatography tandem mass spectrometry was developed. The proposed method is rapid (8 min per sample) with detection limits between 0.1 and 5 ng L- 1 for neonicotinoids and atrazine. For food products (fruits and vegetables), a QuEChERS method was investigated. The optimized procedure shows limits of detection between 0.05 ng g-1 and 2 ng g-1 for a total of 22 pesticides encompassing 7 different classes, including organophosphorus compounds, carbamates, neonicotinoids and triazines, among others. The robustness of the various methods has been demonstrated by inter-day and intra-day iv quality control experiments to ensure suitable accuracy, precision, and the absence of matrix effects in long LC-MS batch sequences. The validated methods were applied to real samples, including tap water samples from 52 municipalities in the province of Quebec (Canada), 68 surface water samples from the St. Lawrence River and its main tributaries, and 133 fruits and vegetables samples (lettuce samples, apples, grapes and tomatoes) purchased from local markets. The results indicate a high occurrence of atrazine, thiamethoxam, clothianidin, and imidacloprid in the water samples and the four food products.

Since their emergence in the early 1990s, neonicotinoid use has increased exponentially to make them the world's most prevalent insecticides. Although there is considerable research concerning the lethality of neonicotinoids, their sub-lethal and developmental effects are still being explored, especially with regards to non-mammalian species. The goal of this research was to investigate the effects of the neonicotinoid imidacloprid on the morphological and physiological development of northern bobwhite quail (Colinus virginianus). Bobwhite eggs (n = 650) were injected with imidacloprid concentrations of 0 (sham), 10, 50, 100 and 150 grams per kilogram of egg mass, which was administered at day 0 (pre-incubation), 3, 6, 9, or 12 of growth. Embryos were dissected on day 19 when they were weighed, staged, and examined for any overt structural deformities. Embryonic heart, liver, lungs and kidneys were also weighed and preserved for future use. Treated embryos exhibited increased frequency of severely deformed beaks and legs, as well as larger hearts and smaller lungs at the higher dosing concentrations. Some impacts are more pronounced in specific dosing periods, implying that there may be critical windows of development when embryos are highly susceptible to neonicotinoid exposure. This investigation suggests that imidacloprid could play a significant role in chick survival and declining quail populations in treated regions of the country.

<p>U okviru ove doktorske disertacije pažnja je sa jedne strane posvećena razradi NMR&nbsp;spektrometrijskih i veoma osetljivih hromatografskih (HPLC/DADi HPLC/TLS) metoda, a sa&nbsp;druge strane razradi jednostavnijih spektrofotometrijskih i voltametrijskih metoda za određivanje&nbsp;odabranih neonikotinoida. Kao posebno vredan doprinos, razrađena je metoda pripreme ekolo&scaron;ki&nbsp;pogodne bizmut-film elektrode na staklastom ugljeniku i na planarnoj ugljeničnoj elektrodi.&nbsp;Efikasnost elektrode je upoređena sa elektrodom modifikovanom filmom od žive. Za ispitivanje&nbsp;povr&scaron;ine radnih elektroda primenjena je i (SEM/EDS) metoda. Razrađene metode su testirane za&nbsp;određivanje neonikotinoida iz komercijalnih formulacija, kao i iz uzoraka krompira, kukuruza,&nbsp;paprike, meda i povr&scaron;inske vode.</p> / <p>The Ph. D. thesis is concerned with the development of NMR spectrometric and very&nbsp;sensitive chromatographic (HPLC/DAD and HPLC/TLS) methods, on the one&nbsp; hand, and simpler&nbsp;spectrophotometric and voltammetric methods on the other, for the &nbsp;determination of selected&nbsp;neonicotinoids. As an especially valuable contribution, a procedure has&nbsp; been developed for the&nbsp;preparation of an environment-friendly bismuth film electrode on glassycarbon and planar&nbsp;carbon electrode. The achieved efficiency of such electrode was compared with that of mercury&nbsp;film electrode. Surface morphology of the working electrodes was studied by the SEM/EDS&nbsp;method. The developed methods have been tested for the determination of the neonicotinoids from&nbsp;their commercial formulations, as well as from samples of potato,&nbsp; maize, pepper, honey, and&nbsp;surface water.</p>

The purpose for using pesticides is to kill organisms that cause damage (so-called pests) on various crops and thus prevent possible crop losses. Their side effect is a negative impact on non-target organisms. The presented diploma thesis is focused on the effect of neonicotinoids on invertebrates particularly on spiders. Its main goal was to document their influence on behavioral parameters influencing dispersal abilities such as locomotion and tendency to spread by wind (so-called ballooning). The diploma thesis compares the influence of neonicotinoids on model species, Pardosa lugubris (Walckenaer, 1802) and Phylloneta impressa (L. Koch, 1881) with different modes of prey hunting and compares the influence on adult and nymphal stages. Pesticides Actara® 25 WG, Biscaya® 240 OD, Confidor® 200 OD and Mospilan® 20 SP were applied to the spiders under laboratory conditions and their effect was tested at different concentrations and different methods of application. The biggest impact on spiders had Confidor. It clearly had the most significant negative effect on mobility and a tendency to spider wind propagation. The lethal effects were caused by neonicotinoids in nymphal individuals Pardosa lugubris, especially Confidor (even 100% mortality for tarsal application). During an experiment studying the...

In this study, some important aspects of the relationship between honey bees (Apis mellifera L.) and pesticides have been investigated. In the first part of the research, the effects of the exposure of honey bees to neonicotinoids and fipronil contaminated dusts were analyzed. In fact, considerable amounts of these pesticides, employed for maize seed dressing treatments, may be dispersed during the sowing operations, thus representing a way of intoxication for honey bees. In particular, a specific way of exposure to this pesticides formulation, the indirect contact, was taken into account. To this aim, we conducted different experimentations, in laboratory, in semi-field and in open field conditions in order to assess the effects on mortality, foraging behaviour, colony development and capacity of orientation. The real dispersal of contaminated dusts was previously assessed in specific filed trials. The results showed a significant effect on mortality of neonicotinoids and fipronil contaminated dusts, both in laboratory and in semi-field trials. However, no effects were evidenced in honey bees orientation capacity.In the second part, the impact of various pesticides (chemical and biological) on honey bee biochemical-physiological changes, was evaluated. Different ways and durations of exposure to the tested products were also employed. Three experimentations were performed, combining Bt spores and deltamethrin, Bt spores and fipronil, difenoconazole and deltamethrin. Several important enzymes (GST, ALP, SOD, CAT, G6PDH, GAPDH) were selected in order to test the pesticides induced variations in their activity. In particular, these enzymes are involved in different pathways of detoxification, oxidative stress defence and energetic metabolism. The analysis of different biochemical indicators highlighted some interesting physiological variations that can be linked to the pesticide exposure. We therefore stress the attention on the possibility of using such a methodology as a novel toxicity endpoint in environmental risk assessment.

Imidacloprid is a neonicotinoid pesticide used to protect against biting and sucking insects. Land managers rely on its systemic properties, however long-term studies investigating imidacloprid effects on ecosystem function are limited. This study investigated imidacloprid applications to Tsuga caroliniana and Tsuga canadensis over time and compared concentrations to measures of ecosystem function including soil respiration, microbial function, and invertebrate density. Results indicate that imidacloprid is persistent (p0.5). Microbial function and invertebrate density were not significantly different between control and treatment locations nor did imidacloprid concentrations correlate with ecosystem functional indicator activity (p>0.05). It is evident that imidacloprid does not affect ecosystem function over time, however care should be taken when applying it in sensitive locations where endemic, threatened, and endangered organisms reside.

Fruit set in cucurbit crops such as watermelon is entirely dependent upon pollinators, which makes them an important aspect of grower management. This reliance on pollinators means that growers must consider them when making pest management decisions, especially when using pesticides, which can have a negative impact on pollinators. Thus, pest management in watermelon production faces a potential trade-off between pests and pollinators. The ways in which growers manage this trade-off could have a large impact on the communities of both groups and the yield of the crop. <br>

<p><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning /> <w:ValidateAgainstSchemas /> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables /> <w:SnapToGridInCell /> <w:WrapTextWithPunct /> <w:UseAsianBreakRules /> <w:DontGrowAutofit /> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <mce:style><! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0pt 5.4pt 0pt 5.4pt; mso-para-margin:0pt; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} --><!--[endif] --></p><p class="MsoBodyText" style="margin-bottom: 0.0001pt;">U disertaciji je izvr&scaron;ena voltametrijska karakterizacija i određivanje pet&nbsp;neonikotinoidnih insekticida (imidakloprida, tiametoksama, klotianidina, nitenpirama i&nbsp;acetamiprida) na različitim elektrodama na bazi ugljenika, kao &scaron;to su elektroda od&nbsp;ugljenične paste, elektroda od staklastog ugljenika i bizmut-filmom modifikovani&nbsp;staklasti ugljenik. Pored ispitivanja u model-rastvorima, razvijene visokoosetljive&nbsp;diferencijalne pulsne voltametrijskemetode su primenjene za određivanje neonikotinoida&nbsp;u realnim uzorcima. Neonikotinoidi su određivani u uzorcima rečne vode i komercijalnim&nbsp;formulacijama, a praćena je i njihova fotolitička i fotokatalitička razgradnja. Radi&nbsp;potvrđivanja voltametrijskih rezultata, izvedena su komparativna merenja uz primenu&nbsp;tečne hromatografije sa detektorom od niza dioda i infracrvenespektrometrije. Detekcija&nbsp;pojedinih degradacionih proizvoda nastalih u toku ispitivanih fotodegradacionih procesa&nbsp;je praćena tečnohromatografskom metodom sa tandemskom masenospektrometrijskom&nbsp;detekcijom. Proučavana je povr&scaron;inska struktura CR 5 grafitnog praha, elektrode od&nbsp;ugljenične paste na bazi trikrezil-fosfata i elektrode od staklastog ugljenika pomoću&nbsp;skenirajuće elektronske mikroskopije.</p> / <p>This thesis is concerned with the voltammetric characterization and&nbsp;determination of five neonicotinoid insecticides (imidacloprid, thiamethoxam,&nbsp;clothianidin, nitenpyram and acetamiprid) at different carbon-based electrodes such as&nbsp;carbon paste, glassy carbon and bismuth-film modified glassycarbon. In addition to the&nbsp;investigations in model solutions, the developed highly sensitive differential pulse&nbsp;voltammetric methods were applied for the determination of neonicotinoids in real&nbsp;samples. Neonicotinoids were determined in river water samples, commercial&nbsp;formulations, and their photolytic and photocatalytic degradation was also monitored. To&nbsp;confirm the voltammetric results, comparative measurements were performed by liquid&nbsp;chromatography with diode-array detector and infrared spectrometry. Detection of some&nbsp;degradation products formed during the photodegradation processes was monitored using&nbsp;liquid chromatography with tandem mass-spectrometric detection. The surface structure&nbsp;of CR 5 graphite powder, tricresyl phosphate-based carbon paste electrode and glassy&nbsp;carbon electrode was investigated by scanning electron microscopy.</p>