Characterization of Organophosphate Pesticides in Urine and Home Environment Dust in an Agricultural Community

Thesis (Master's)--University of Washington, 2016-06

Public Perceptions and Pesticides - A Case Study of the Willapa Bay Oyster Bed Spraying Permit of 2015

Thesis (Master's)--University of Washington, 2016-06

Factors that influence the prevalence of acaricide resistance and tick-borne diseases

This manuscript provides a summary of the results presented at a symposium organized to accumulate information on factors that influence the prevalence of acaricide resistance and tick-borne diseases. This symposium was part of the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP), held in New Orleans, LA, USA, during August 10-14, 2003. Populations of southern cattle ticks, Boophilus microplus, from Mexico have developed resistance to many classes of acaricide including chlorinated hydrocarbons (DDT), pyrethroids, organ ophosphates, and formamidines (amitraz). Target site mutations are the most common resistance mechanism observed, but there are examples of metabolic mechanisms. In many pyrethroid resistant strains, a single target site mutation on the Na+ channel confers very high resistance (resistance ratios: >1000x) to both DDT and all pyrethroid acaricides. Acetylcholine esterase affinity for OPs is changed in resistant tick populations. A second mechanism of OP resistance is linked to cytochrome P450 monooxygenase activity. A PCR-based assay to detect a specific sodium channel gene mutation that is associated with resistance to permethrin has been developed. This assay can be performed on individual ticks at any life stage with results available in a few hours. A number of Mexican strains of B. microplus with varying profiles of pesticide resistance have been genotyped using this test. Additionally, a specific metabolic esterase with permethrin-hydrolyzing activity, CzEst9, has been purified and its gene coding region cloned. This esterase has been associated with high resistance to permethrin in one Mexican tick population. Work is continuing to clone specific acetylcholinesterase (AChE) and carboxylesterase genes that appear to be involved in resistance to organophosphates. Our ultimate goal is the design of a battery of DNA- or ELISA-based assays capable of rapidly genotyping individual ticks to obtain a comprehensive profile of their susceptibility to various pesticides. More outbreaks of clinical bovine babesisois and anaplasmosis have been associated with the presence of synthetic pyrethroid (SP) resistance when compared to OP and amidine resistance. This may be the result of differences in the temporal and geographic patterns of resistance development to the different acaricides. If acaricide resistance develops slowly, herd immunity may not be affected. The use of pesticides for the control of pests of cattle other than ticks can affect the incidence of tick resistance and tick-borne diseases. Simple analytical models of tick- and tsetse-bome diseases suggest that reducing the abundance of ticks, by treating cattle with pyrethroids for example, can have a variety of effects on tick-bome diseases. In the worst-case scenario, the models suggest that treating cattle might not only have no impact on trypanosomosis but could increase the incidence of tick-bome disease. In the best-case, treatment could reduce the incidence of both trypanosomosis and tick-bome diseases Surveys of beef and dairy properties in Queensland for which tick resistance to amitraz was known were intended to provide a clear understanding of the economic and management consequences resistance had on their properties. Farmers continued to use amitraz as the major acaricide for tick control after the diagnosis of resistance, although it was supplemented with moxidectin (dairy farms) or fluazuron, macrocyclic lactones or cypermethrin/ chlorfenvinphos. (C) 2004 Published by Elsevier B.V.

Discrimination among host plants (Leucaena species and accessions) by the psyllid pest Heteropsylla cubana and implications for understanding resistance

1 The herbivorous bug Heteropsylla cubana Crawford (Homoptera: Psyllidae) is a pest of the cattle fodder crop Leucaena (Leguminosae: Mimosoideae). The interaction between the psyllid and three varieties of its Leucaena host plant was investigated in relation to the apparent resistance of some Leucaena varieties (Leucaena leucocephala, Leucaena pallida and their hybrids) to attack. 2 Field trials demonstrated that adult psyllids distinguished among the different varieties of Leucaena over a distance, and were attracted to L. leucocephala in significantly higher numbers than to L. pallida or to the hybrid. Pesticide treatment increased the attractiveness of Leucaena plants, even of those deemed to be psyllid resistant. Numbers of psyllid eggs and nymphs, sampled in the field, reflect the arrival rates of adults at the three plant varieties. 3 Wavelength reflectance data of the three Leucaena varieties were not significantly different from one another, suggesting that psyllids cannot discriminate among the three plants using brightness or wavelength cues. There was a differential release of caryophyllene among the three varieties. Release of caryophyllene in L. leucocephala and the hybrid appeared to be influenced by environmental conditions. 4 Experiments demonstrated that caryophyllene (at least on its own) did not influence the behaviour of leucaena psyllids in relation to leucaena plants. 5 The results suggest that host plant volatiles cannot be dismissed as significant in the interaction between the leucaena psyllid and its Leucaena host plants. Further avenues for investigation are recommended and these are related to novel ways of understanding resistance in insect plant inter-relationships.

Effects of Photosystem II inhibiting herbicides on mangroves - preliminary toxicology trials

Mangroves are sensitive to the root application of Photosystem II inhibiting herbicides and Avicennia marina is more sensitive than other mangroves tested. Seedlings of four mangrove species, including two salt-excreting species (A. marina and Aegiceras corniculatum) and two salt-excluding species (Rhizophora stylosa and Ceriops australis) were treated with a range of concentrations of the herbicides diuron, ametryn and atrazine. Assessment of responses required the separation of seedlings into two groups: those that had only their roots exposed to the herbicides through the water (A. marina and R. stylosa) and those that had both roots and leaves exposed to herbicides through the water (A. corniculatum and C australis). Salt-excreting species in each group were more susceptible to all herbicide treatments than salt-excluding species, indicating that root physiology was a major factor in the uptake of toxic pollutants in mangroves. Submergence of leaves appeared to facilitate herbicide uptake, having serious implications for seedling recruitment in the field. Each herbicide was ranked by its toxicity to mangrove seedlings from most damaging to least effective, with diuron > ametryn > atrazine. The relative sensitivity of A. marina found in these pot trials was consistent with the observed sensitivity of this species in the field, notably where severe dieback had specifically affected A. marina in the Mackay region, north eastern Australia. (c) 2004 Elsevier Ltd. All rights reserved.

Dissipation of acetochlor and its distribution in surface and sub-surface soil fractions during laboratory incubations

Pesticides in soil are subject to a number of processes that result in transformation and biodegradation, sorption to and desorption from soil components, and diffusion and leaching. Pesticides leaching through a soil profile will be exposed to changing environmental conditions as different horizons with distinct physical, chemical and biological properties are encountered. The many ways in which soil properties influence pesticide retention and degradation need to be addressed to allow accurate predictions of environmental fate and the potential for groundwater pollution. Degradation and sorption processes were investigated in a long-term (100 days) study of the chloroacetanilide herbicide, acetochlor. Soil cores were collected from a clay soil profile and samples taken from 0-30cm (surface), 1.0-1.3m (mid) and 2.7-3.0m (deep) and treated with acetochlor (2.5, 1.25, 0.67 mu g acetochlor g(-1) dry wt soil, respectively). In sterile and non-sterile conditions, acetochlor concentration in the aqueous phase declined rapidly from the surface and subsoil layers, predominantly through nonextractable residue (NER) formation on soil surfaces, but also through biodegradation and biotic transformation. Abiotic transformation was also evident in the sterile soils. Several metabolites were produced, including acetochlor-ethane sulphonic acid and acetochlor-oxanilic acid. Transformation was principally microbial in origin, as shown by the differences between non-sterile and sterile soils. NER formation increased rapidly over the first 21 days in all soils and was mainly associated with the macroaggregate (> 2000 mu m diameter) size fractions. It is likely that acetochlor is incorporated into the macroaggregates through oxidative coupling, as humification of particulate organic matter progresses. The dissipation (ie total loss of acetochlor) half-life values were 9.3 (surface), 12.3 (mid) and 12.6 days (deep) in the non-sterile soils, compared with 20.9 [surface], 23.5 [mid], and 24 days [deep] in the sterile soils, demonstrating the importance of microbially driven processes in the rapid dissipation of acetochlor in soil.

Sequencing a new target genome: The Boophilus microplus (Acari : Ixodidae) genome project

The southern cattle tick, Boophilus microplus (Canestrini), causes annual economic losses in the hundreds of millions of dollars to cattle producers throughout the world, and ranks as the most economically important tick from a global perspective. Control failures attributable to the development of pesticide resistance have become commonplace, and novel control technologies are needed. The availability of the genome sequence will facilitate the development of these new technologies, and we are proposing sequencing to a 4-6X draft coverage. Many existing biological resources are available to facilitate a genome sequencing project, including several inbred laboratory tick strains, a database of approximate to 45,000 expressed sequence tags compiled into a B. microplus Gene Index, a bacterial artificial chromosome (BAC) library, an established B. microplus cell line, and genomic DNA suitable for library synthesis. Collaborative projects are underway to map BACs and cDNAs to specific chromosomes and to sequence selected BAC clones. When completed, the genome sequences from the cow, B. microphis, and the B. microphis-borne pathogens Babesia bovis and Anaplasma marginale will enhance studies of host-vector-pathogen systems. Genes involved in the regeneration of amputated tick limbs and transitions through developmental stages are largely unknown. Studies of these and other interesting biological questions will be advanced by tick genome sequence data. Comparative genomics offers the prospect of new insight into many, perhaps all, aspects of the biology of ticks and the pathogens they transmit to farm animals and people. The B. microplus genome sequence will fill a major gap in comparative genomics: a sequence from the Metastriata lineage of ticks. The purpose of the article is to synergize interest in and provide rationales for sequencing the genome of B. microplus and for publicizing currently available genomic resources for this tick.

The fabrication of biodegradable nanospheres from novel hydroxalkanoates for the delivery of actives of pharmaceutical and agricultural interest

This work describes the fabrication of nanospheres from a range of novel polyhydroxyalkanoates supplied by Monsanto, St Louis, Missouri, USA for the delivery of selected actives of both pharmaceutical and agricultural interest. Initial evaluation of established microsphere and nanosphere fabrication techniques resulted in the adoption and optimisation of a double sonication solvent evaporation method involving the synperonic surfactant F68. Nanospheres could be consistently generated with this method. Studies on the incorporation and release of the surrogate protein Bovine Serum Albumin V demonstrated that BSA could be loaded with between 10-40% w/w BSA without nanosphere destabilisation. BSA release from nanospheres into Hanks Balanced Salts Solution, pH 7.4, could be monitored for up to 28 days at 37°C. The incorporation and release of the Monsanto actives - the insecticide Admire® ({ 1-[(6-chloro-3-pyridinyl)methyIJ-N-nitro-2-imidazolidinimine}) and the plant growth hormone potassium salt Gibberellic acid (GA3K) from physico-chemically characterised polymer nanospheres was monitored for up to 37 days and 28 days respectively, at both 4°C and 23°C. Release data was subsequently fitted to established kinetic models to elaborate the possible mechanisms of release of actives from the nanospheres. The exposure of unloaded nanospheres to a range of physiological media and rural rainwater has been used to investigate the role polymer biodegradation by enzymatic and chemical means might play in the in vivo release of actives and agricultural applications. The potential environmental biodegradation of Monsanto polymers has been investigated using a composting study (International Standard ISO/FDIS 14855) in which the ultimate aerobic biodegradation of the polymers has been monitored by the analysis of evolved carbon dioxide. These studies demonstrated the potential of the polymers for use in the environment, for example as a pesticide delivery system.

Some aspects of the analytical chemistry of malathion

A thorough investigation of the recommended colorimetric method for the determination of malathion (an organophosphorus pesticide) has led to the identification of the major cause of all the problems with which the method suffers. The method, which involves the extraction of the copper (II) complex or the hydrolysis product of malathion from aqueous solution into immiscible organic solvents, has many drawbacks. For example, the colour of the organic extract fades very quickly and a slight increase in the contact time of the hydrolysis product and the copper reagent within the aqueous solution, results in a decrease in the ab-solute absorbance. Also, the presence of any reducing agents can be a significant source of error. In the present work, it has been shown that the basic cause of all these problems is the ability of copper (II) ion to be reduced to copper (I) ion. It has further been shown that these problems can be resolved by re-placing copper (II) by bismuth (III). This has led to the development of a modified colorimetric method for the determination. of malathion, which has distinct advantages over all other existing methods in terms of reagents required, ease in application, avoidance of interferences and stability of colour for extended periods of time. The modified colorimetric method described above has been further improved by making use of a ligand exchange reaction involving dithizone. The resulting final organic extract in this case is bright orange in colour, the absorbance of which can be measured even with simple photometers. The usefulness of the modified colorimetric method has been demonstrated by determining malathion in technical products, and in aqueous solution containing the compound down to sub ppm levels. The scope and applicability of atomic absorption spectrophotometry has been extended by demonstrating for the first time that the technique can be used for the indirect determination of malathion. Almost all of the work described above has been accepted for publication by international journals and considerable interest in the work has been shown by chemists working in the field of pesticide analysis and research.

The effects of the fungicides fenhexamid and myclobutanil on SH-SY5Y and U-251 MG human cell lines

Mixtures of pesticides in foodstuffs and the environment are ubiquitous in the developed world and although agents are usually exhaustively tested individually, the toxicological implications of pesticide mixtures are underreported. In this study, the effects of two fungicides, fenhexamid and myclobutanil were investigated individually and in combination on two human cell lines, SH-SY5Y neuronal cells and U-251 MG glial cells. After 48. h of incubation with increasing concentrations of pesticides ranging from 1 to 1000. μM, gene expression profiles were studied in addition to toxicity end points, including cell viability, mitochondrial depolarisation as well as cellular glutathione maintenance. There were no significant differences between the susceptibility of the two cell lines in terms of cell viability assessment or mitochondrial membrane potential, when agents were administered either individually or in combination. By contrast, in the presence of the fungicides, the SH-SY5Y cells showed significantly greater susceptibility to oxidative stress in terms of total thiol depletion in comparison with the astrocytic cells. Treatment with the two pesticides led to significant changes in the cell lines' expression of several genes which regulate cell cycle control and growth (RB1, TIMP1) as well as responses to DNA attrition (ATM and CDA25A) and control of apoptosis (FAS). There was no evidence in this study that the combination of fenhexamid and myclobutanil was significantly more toxic than individual exposure, although gene expression changes suggested there may be differences in the sub-lethal response of both cell lines to both individual and combined exposure.

The potential application of pyroligneous acid in the UK agricultural industry

This paper highlights the potential benefits of smoke recovery from the production of biochar in crop management through it application as an antimicrobial agent against plant disease and as a pesticide. The study reports on the findings of zone inhibition assays on selected plant pathogens (Agrobacterium tumefacien and Xanthomonas campestris), growth studies on selected plants (Raphanus sativus and Vicia faba), and toxicity studies performed on arthropods (Myzus persicae and Tetranychus urticae). The results suggested a strong benefit to crop management in terms of crop protection against selected causal agents responsible for plant disease, with zones of inhibition observed on both Agrobacterium tumefacien and Xanthomonas campestris when inoculated with pyroligneous acid (liquid smoke) at 10% dilution. Similarly, its potential as a bio-pesticide are favorable, with a reported 20%–30% of arthropods affected (knocked out/mortality) after exposure for 48 hours.

An aquatic risk assessment of ethion and bromacil inputs to the C-25 Canal and Indian River Lagoon

Pesticide monitoring in St. Lucie County by various local, state and federal agencies has indicated consistent residues of several pesticides, including ethion and bromacil. Although pesticides have long been known to pose a threat to non-target species and much background monitoring has been done, no pesticide aquatic risk assessment has been done in this geographical area. Several recognized United States Environmental Protection Agency (USEPA) methods of quantifying risk are employed here to include hazard quotients (HQ) and probabilistic modeling with sensitivity analysis. These methods are employed to characterize potential impacts to aquatic biota of the C-25 Canal and the Indian River Lagoon (in St. Lucie County, Florida) based on current agricultural pesticide use and drainage patterns. The model used in the analysis incorporates available physical-chemical property data, local hydrology, ecosystem information, and pesticide use practices. HQ's, probabilistic distributions, and field sample analyses resulted in high levels of concern (LOCs), which usually indicates a need for regulatory action, including restrictions on use, or cancellation. ^

Efeitos de fungicidas alternativos em folhas de Carthamus tinctorius L. (Asteraceae), potencial espécie para cultivo em agricultura familiar

The currently main development model on global society is driven by an economic rationality that endangers the environment and social justice. More and more, attention to this way of production and consumption is increasing, boosting research for sustainable development, with an environmental rationality that can harmonize nature preservation and welfare of all socioeconomic classes. One of the efforts on this sense is changing the sources supplying the energy demand, replacing fossil fuels for renewable and cleaner sources, such as biofuels. Carthamus tinctorius (safflower) is an oilseed crop with potential for biodiesel production, with good oil yield and chemical profile, allied to good adaptation to climates such like the northeastern semiarid lands of Brazil. With public policies fomentation, the use of this species may be an interesting alternative for family farming. In farming in general, the use of pesticides to prevent and combat diseases and plagues is common, which is not a sustainable practice. Thus, there are researched alternative, less dangerous substances. In this study, it was aimed to assess if neem (Azadirachta indica) leaf extract (20% m/v) and Bordeaux mixture (copper sulfate) have effects on safflower. It was also aimed to verify acceptance of farmers on safflower crop in Apodi, a municipality in Rio Grande do Norte state, Brazil, in view of it being localized in the aimed region for this crop cultivation. Besides that, understanding that the farmers’ knowledge and inclination to adopt the crop is fundamental for the introduction of this species and socioeconomic growth due to its exploration. In addition, a booklet with basic information on safflower was produced. In the field experiment, the fungicides were pulverized on plants cultivated in field experimental plots, with collection of leaf samples for analysis on anatomy, cuticle, and epicuticular wax morphology, the protective layer that interfaces with the surrounding ambient. In Apodi, forty-five farmers from Potiguar Cooperative of Apiculture and Sustainable Rural Development (COOPAPI) underwent semi-structured interviews, which also addressed their assessment on currently cultivated crops and perception of pesticide uses and sustainable alternatives. After comparing using analysis of variance, it was found that there was no difference between treatments in the experiment, as well as no anatomical or morphological modifications. Safflower acceptation among farmers was wide, with 84% of interviewees believing in a perspective of good incomes. The current scenario, comprised of low crop diversity, fragile in face of droughts and plagues, can partially explain this opinion. The booklet was effective in catching people attention for the species potential. There was wide acknowledgement on the importance of alternative pesticides, justified by health security. Based on the assessed parameter in the results of this research, the treatments here utilized may be recommended as fungicides for safflower. Given the crop susceptibility to fungi in heavy rainy period, it is advised that its potential introduction on the region shall be focused on semiarid areas.

Investigação da rota biohidrometalúrgica com Acidithiobacillus ferrooxidans/thiooxidans para recuperação do cobalto de baterias de íons lítio descartadas

The recycling of metals from secondary sources can be advantageous. Among the metals of interest, we have cobalt, a metal used for various purposes. As regards the secondary sources of cobalt, the lithium-ion batteries can be considered, since they contain cobalt oxide in their composition (LiCoO2). This way, the objective of this work was to use the microorganism strains (Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans) to bioleach the LiCoO2 extracted from discarded lithium ion batteries with emphasis on the recovery of cobalt for synthesis of new materials of interest. The lineage growth occurred in T&K medium and the growth investigation was made by observing the media, by platelet growth and microscope analysis. Then, the inoculum was standardized on 5 x 106 cells mL-1 and used in bioleaching tests. The bioleaching was investigated: the microorganism nature: separate strains and A. ferrooxidans and A. thiooxidans consortium, bioleaching time (0 to 40 days), inoculum proportion (5 to 50% v/v), energy source (iron and sulfur) and residue concentration (1063 to 8500 mg L-1 of cobalt). The cobalt concentration in the media was found by atomic absorption spectrometry and the medium pH was monitored during the bioleaching. The results show that the amount of bioleached cobalt increases with time and the iron concentration. The bioleaching with A. thiooxidans was not influenced by the addition of sulfur. The use of the two lineages together did not improve the bioleaching rates. Among the lineages, the A. thiooxidans presented better results and was able to bioleach cobalt amounts above 50% in most of the experiments. A. thiooxidans presented lower bioleaching rates, with a maximum of 50% after 24 days of experiment. After reprocessing by bioleaching, the cobalt in solution was used for synthesis of new materials: such as LiCoO2 cathode and as adsorbent pesticide double lamellar hydroxide (HDL Co-Al-Cl) by the Pechini and co-precipitation methods. The reprocessed LiCoO2 presented a unique stoichiometric phase relative to the HT-LiCoO2 structure similar to the JCPDS 44-0145, presenting electrochemical activity when tested as a cathode material. The double lamellar hydroxide Co-Al-Cl was tested as pesticide adsorbent, being possible to adsorb around 100% of the pesticide. The bioleaching was efficient in the recovery of cobalt present in lithium-ion batteries and microorganisms presented high tolerance to the residue, being able to bioleach even at higher LiCoO2 concentrations. The cobalt bioleaching medium did not impair the synthesis phases and the obtained materials presented structure and activity similar to the sintered materials from the reagents containing cobalt.