Squoxin (1,1'-Methylendi-2-napthol) was tested in laboratory and field bioassays to evaluate its biological activity to rainbow trout (Salmo gairdneri), cutthroat trout (Salmo clarki), Utah chub (Gila atraria), carp (Cyprinus carpio), reside shiner (Richardsonius balteatus), and mountain sucker (Catostomus platyrhynchus) under various conditions of water quality and temperature. The compound was toxic to all species and most effective from greatest to least to mountain sucker, reside shiner, Utah chub, cutthroat trout, and rainbow trout and carp. Selectively and safety indices for Utah chub compared with the two species of trout indicated a selective control potential for squoxin in hard water at 12.1C and very hard water at 5.6C and 18C. Efficacy of squoxin for selective control of Utah chub in trout waters was similar to the selective control of the sea lamprey (Petromyzon marinus) with 3-trifluoromethyl-4-nitophenol (TFM) in which selection of time and place precedes toxicant use. The toxicity of squoxin was affected more by water temperature than by different water hardnesses or pH. The cumulative effects of various biological, chemical, and physical factors in field tests significantly reduced the toxicity of squoxin to fish.

There has been an increase in the incorporation of silver nanomaterials into consumer products due to their antimicrobial properties. Therefore there is potential for silver nanoparticles (Ag-NPs) to leach out into the environment during different life-cycle stages of these nanomaterial-containing products. Concern about the toxicity of Ag-NPs has led to investigations into their toxic effects on a variety of organisms mainly using acute and sub-chronic, single-generation exposures. The focus of this project was to understand the effects of long-term continuous multigenerational exposure to AgNO3 and Ag-NPs in both pristine and environmentally transformed forms, on the model organism, Caenorhabditis elegans, a soil nematode. A previous multigenerational C. elegans study, showed increased sensitivity in terms of reproductive toxicity, in response to AgNO3 and Ag-NPs, but not sulfidized Ag-NPs (sAg-NPs), with increasing generations of exposure. The reproductive toxicity persisted in subsequently unexposed generations even after rescue from the exposure. We hypothesized that genomic mutations and/or epigenetic changes were possible mechanisms by which the reproductive toxicity was inherited. We investigated the potential for induction of germline mutations in C. elegans after exposures for ten generations to AgNO3, Ag-NPs, and sAg-NPs using whole genome DNA sequencing. Epigenetic changes at histone methylation markers, (H3K4me2 and H3K9me3), and DNA methylation at adenosine (N6-methyl-2’-deoxyadenosine) were investigated after multigenerational exposure as well as after rescue from the exposure using enzyme-linked immunosorbent assays (ELISA) and liquid chromatography with tandem mass spectrometry (LC-MS/MS), respectively. Expression levels of the genes of methyltransferases and demethylases, associated with the histone methylation markers and DNA methylation, were also examined. Our results for germline mutations reveal no significant differences between the nematodes exposed to AgNO3 or pristine Ag-NPs when compared to controls. The significant increase in the number of transversion was observed only for sAg-NPs. However, a trend toward an increase in the total number of mutations was observed in all Ag treatments with some of those mutations having a predicted moderate or high impact. This potentially contributed towards reproductive as well as growth toxicity shown previously after ten generations of exposure in every treatment.. These results did not entirely support the multigenerational reproductive toxicity observed previously. Epigenetic responses at histone methylation markers revealed opposite patterns between pristine and transformed Ag-NPs with Ag-NPs causing a significant increase while exposure to sAg-NPs resulted in significant decrease in methylation at H3K4me2 mark. The increase in H3K4me2 levels was also inherited by subsequent unexposed generations rescued from Ag-NP exposure. Only sAg-NPs caused a significant decrease in methylation at H3K9me3 mark. Changes in mRNA levels for histone methyltransferases and demethylase corresponded with the histone methylation levels affected by Ag-NPs and sAg-NPs. For DNA methylation, a significant increase was observed only for AgNO3, which was not inherited after the rescue. In conclusion, while germline mutations with a high or moderate impact may affect reproduction, our results do not support this as a mechanism for the heritable increase in C. elegans sensitivity to reproductive toxicity from AgNO3 and pristine Ag-NPs. The epigenetic changes, however, do show partial correlation with the observed reproductive toxicity. The reproductive multigenerational effects of AgNO3 can be attributed to changes in DNA methylation whereas that of Ag-NPs can be attributed to changes in histone methylation. Further studies, focused on the investigation of changes in histone and DNA methylation levels at specific loci using chromatin immunoprecipitation sequencing (ChIP-Seq) and methylated DNA immunoprecipitation sequencing (MeDIP-Seq), respectively, are warranted for a better understanding of the impact of such changes.

Agrochemical use has been increasing in both developing and the developed nations. The unsafe handling and use of agrochemicals can lead to accumulation of hazardous chemicals in the body, causing adverse effects on health. This quantitative cross sectional study sought to understand the level of awareness, practices, and perceptions of safe chemical handling by agrochemical using the Theory of Planned Behavior. This study was conducted among 260 farmers in Plateau State, Nigeria. Data on background knowledge and practices of safe agrochemical handling by farmers were collected using a structured paper based, interviewer-€administered questionnaire. Descriptive statistics revealed that the most practiced precautions by participants were washing work clothes separately (56.9%) and taking a shower soon after application of agrochemicals (53.6%). Findings from this study suggest that farmers had good knowledge of safe use of agrochemicals and majority of them 91.9% were knowledgeable about the possible effects of these chemicals on health. A Chi square test showed a statistically significant association between marital status and engagement in safe agrochemical handling X2 (2, N = 260) = 7.34, p <. 05 and level of education X2 (4, N = 260) = 35.12, p <. 05. Results of Binary logistic regression indicated that the variable training on safe agrochemical handling with an odds ratio 8.31 was a good predictor for safe agrochemical handling An important finding in this study however was a low level of adoption for the use of Personal Protective Equipment. Priority should be given to developing safety educational and certification programs for farmers with emphasis on the safe handling practices.

Investigate the interaction of nanomaterials with biological systems, known as nano-bio interaction is of great interest for the assessment of the concern arising from nanomaterials progressive use. Such interaction determines nanomaterials potential effect on human and environment becomes more and more important to understand how they interact with living organisms and the environment. The novel physicochemical characteristics of nanomaterials, such as their small size, large surface area to volume ratio and surface energy, may initiate new toxicological effects due to nanomaterials ability to enter into the biological systems through adsorption and dissolution and modify the structure of various macromolecules An example of these interactions is the adsorption of proteins on nanoparticles surface forming what is known as the 'protein corona'. Therefore, being able to understand how these molecules and other biologically important species are adsorbed and interact, should help us to reduce any adverse impacts of nanoparticles on human health and the environment. Due to the importance of surface composition and surface functionality in nanotoxicology, analytical tools that can probe the change in the structure and composition of the nanoparticles in aqueous media are crucial but remain limited. Therefore in this work, in situ characterization of the liquid–solid interface to probe surface adsorption of environmentally and biologically relevant media on nanoparticle surfaces has been conducted. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy provides the molecular information that allows for the determination of the adsorption mode such as conformational and structural changes of the coordinating ligand. Surface adsorption of titanium dioxide (TiO2) nanoparticles have been investigated in different biological media typically used for toxicity studies and show that the surface composition of TiO2 nanoparticles depends to a large extent on the composition of the medium due to surface adsorption. Moreover, hydrodynamic diameter and surface charge of TiO2 NPs were evaluated using dynamic light scattering DLS. The results indicated that TiO2 NPs undergo different trends in aggregation upon the adsorption of biological media on its surface and zeta potential measurements showed surface charge alterations which are consistent with the aggregation study. In order to understand the dynamic transformations of nanomaterials in biological environments, the effect of dissolution has been predicted. Copper oxide CuO and zinc oxide ZnO nanoparticles were used to study dissolution due to their instability in biological media. Once these particles exposed to solutions they release their ions and tend to aggregate. Therefore, the dissolution of these materials was conducted at size ca. 24 nm and nanoparticles coated with proteins and humic acid employing simulated lung fluids as models to develop a better understanding of how these properties effect the solubility and stability in biological systems. From this study, it was found that both copper oxide and zinc oxide NPs showed different trends in dissolution. Cu and Zn ions once coated with proteins and HA highly dissolved in ALF at low pH 4.5 compared with other fluids (Gamble’s solution and water) at extracellular pH which shows only slightly enhanced in the basal condition. The acidity of ALF may explain the higher solubility of metals that are phagocytized versus those that remain extracellular. Some general conclusions can be drawn from these investigations. It seems that analytical tools to characterize the interfacial region between nanopaerticles and these complex systems provide a reasonably good qualitative and quantitative description of the interactions.

Chlorophyll and solanine syntheses as influenced by cultivars, specific gravities, light intensities, and duration of exposure to light were studied in potato (Solanum tuberosum, L.) tubers. Chemicals, gamma radiation, clear polyethylene packaging in 15 per cent co 2 , and storage at subatmospheric pressure were employed to control the formation of these two compounds. The toxicity of solanine to mice, the fungus Trichoderma viride, and cholinesterase inhibition patterns in rabbits and a dog were evaluated. The influence of the central nervous system stimulating drugs was investigated to find if they counteracted solanine toxicity. Of the 11 cultivars tested, tubers of Bounty, Kennebec, Nor chip, and Red Lasoda were most sensitive to greening and solanine development. LaChipper and Platte tubers were least susceptible to greening and their solanine contents were minimum. The significant differences in chlorophyll and solanine formation among cultivars showed that greening potential is a cultivar characteristic. xi Chlorophyll development in tubers was inversely related to their specific gravity. Solanine synthesis was, however, not dependent on specific gravity. Studies on effect of four light intensities on Kennebec potato tubers that were stored for nearly 6 months showed that more chlorophyll formed at 100 and 150 ft-c than at 50 and 200 ft-c light intensities. Generally, chlorophyll formation increased with increased light intensity up to 100 ft-c, slowly and steadily declined up to 150 ft-c, and sharply declined at 200 ft-c. There were no significant differences in the solanine contents of the tubers after exposure to these light intensities. The duration of exposure of the tubers to 100 ft-c revealed that solanine and chlorophyll contents increased linearly with the duration of exposure up to the sixth and tenth day, respectively. There was no difference in the amount of chlorophyll formed at the end of the tenth and fifteenth day. The solanine contents were rather constant from the sixth to the tenth day and then slightly declined at the end of the fifteenth day. The respiration of the tubers did not seem to have an apparent relationship to solanine and chlorophyll formation. Investigation on the control of greening showed that two chemicals, Ethrel (2-chloroethylphosphonic acid) and Alar (succinamic acid, 2, 2-dimethylhydrazide) when applied at 10, 000 ppm by vacuum injection technique, were significantly effective in inhibiting chlorophyll and solanine syntheses. Ethrel was most effective in controlling the chlorophyll formation and the least solanine xii was formed after the Alar treatment. The dose of 10 krads of gamma radiation inhibited 80 per cent, while polyethylene packaging with 15 per cent co 2 , only 32 per cent of chlorophyll synthesis. Storage of tubers at subatmospheric pressure of 126 mm-Hg resulted in complete inhibition of chlorophyll formation. The irradiation, co 2 environment either alone or in combination, and subatmospheric pressure treatments did not affect solanine synthesis. Solanine was toxic to mice, rabbits, a dog, and the fungus Trichoderma viride. The LD 50 for intraperitoneal (ip) administration, single dose, in mice was 32. 3 mg of solanine per Kg body weight, the 19/20 confidence limits being 27. 6 - 37. 9 mg. Plasma and erythrocytic cholinesterase inhibition in rabbits indicated that solanine was a weak to moderate inhibitor of both specific and nonspecific cholinesterase. There was less inhibition of erythrocytic cholinesterase than that of plasma in vivo. In an anesthetized dog, cumulative doses of solanine showed a quick inhibition of cholinesterase but rapid recovery · was noted in the case of serum enzyme, while there was no inhibition of the red cell enzyme. A prior intraperitoneal dose of 2 mg/Kg of atropine sulfate lowered the mortality after ip injection into mice at 40 mg/Kg of solanine from 9/10 to 5/10. Similar application of pargyline (5 mg/Kg ip) and amphetamine (5 mg/Kg ip) had no effect on mortality from solanine. Atropine influence appeared antagonistic and counteracted solanine toxicity. The concentration of 10 mg of solanine per 100 ml of potato-dextroseagar medium had no effect on the Trichoderma viride fungus growth, while at a concentration of 200 mg, the growth ceased. The (Lethal Concentration) Lc 50 was 102. 2 mg/100 ml, and 19/20 confidence limits being 83. 85 - 124. 6 mg.

Vanadium compounds have been reported to cause numerous toxicological effects including NAD(P)H oxidation and lipid peroxidation. The purpose of this thesis is to determine the active form of vanadium in causing these effects, and to determine any possible free radical involvement in these processes. Vanadium-stimulated oxidation of NADH was studied spectrophotometrically and by electron spin resonance spectroscopy. In 25 mM sodium phosphate buffer at pH 7. 4, vanadyl , (V(IV)), is slightly more effective in stimulating NADH oxidation than was vanadate (V(V)). Addition of a superoxide generating system, xanthine/xanthine oxidase, results in a marked increase in NADH oxidation by vanadyl, and to a lesser extent, by vanadate. In contrast, addition of hydrogen peroxide did not change the NADH oxidation by vanadate, but greatly enhanced NADH oxidation by vanadyl. Use of the spin trap DMPO in reaction mixtures containing vanadyl and hydrogen peroxide or a superoxide generating system resulted in the detection by ESR of hydroxyl radical. Hydroxyl radical was also detected in the system containing vanadate plus superoxide. It was found that superoxide is capable of reducing vanadate to vanadyl, and that vanadyl is capable of reaction with hydrogen peroxide in a Fenton-like mechanism to produce hydroxyl radical. Hydroxyl radical is suggested to be the active species involved in NADH oxidation. Other reductants, such as thiols, are also capable of supporting vanadate-stimulated NADH oxidation . The above results indicat that ability of vanadium to act in a Fenton-like mechanism is an important process in the vanadium-stimulated oxidation of NADH. Vanadyl was found to be the active form of vanadium involved in initiating and stimulating lipid peroxidation in purified and partially purified fatty acid micelle preparations. Hydroxyl radicals were shown to be involved in initiating diene conjugation when vanadyl and hydrogen peroxide were added together in the reaction mixture. Furthermore, hydroxyl radicals were shown to be generated in the vanadyl-catalyzed decomposition of fatty acid lipoperoxides. The results of this study indicat that the ability of vanadium compounds to oxidize NADH and to stimulate lipid peroxidation are related by the common mechanism of hydroxyl radical production from the reaction of vanadyl with hydrogen peroxide.

A micromorfologia é a ciência que permite estudar o solo e seus componentes em amostras indeformadas em uma escala microscópica permitindo identificar feições relacionados a sua formação e processos atuantes que podem ser aplicadas em estudos de gênese, física, mineralogia, microbiologia do solo, entre outros. Para que isso seja possível é necessário formar um material rígido o suficiente para ser laminado a partir de amostras indeformadas de solo, através do processo de impregnação de solo. No entanto, para esse procedimento são utilizados atualmente, resinas plásticas (e.g. poliéster e epóxi), e dentre elas a resina poliéster, pode ser consideradas tóxica à saúde humana devido a presença do monômero de estireno na composição, além disso há o risco de danos ao meio ambiente devido a produção de resíduos oriundos de materiais tóxicos. No Brasil, por exemplo, há poucos laboratórios que realizam o processo de impregnação de amostras de solos para análises micromorfológicas, provavelmente, devido a toxicidade dos reagentes. Diante da importância da técnica para a Ciência do Solo, torna-se fundamental buscar alternativas para a técnica de micromorfologia do solo, que sejam economicamente viáveis, e que assegurem a segurança de atividades que envolvam substâncias e produtos químicos, visando garantir a proteção da saúde, da vida e das condições normais do ambiente, contribuindo para um desenvolvimento sustentável sem comprometer a qualidade do produto final. Assim, o presente trabalho teve como objetivo eliminar ou substituir a utilização do monômero de estireno no processo de impregnação de solos por substâncias similares menos tóxicas ao manuseio e avaliar o uso de soluções de resina poliéster e soluções de resina epóxi com diferentes diluentes (estireno, acetona e álcool) no processo de impregnação de amostras de solo (argiloso, textura média e arenoso). Para isso, foram utilizadas 2 tipos de resinas: resina poliéster Arazyn 1.0#00, resina poliéster Arazyn 1.0#0.8 e resina Epóxi Epoxiglass 1504; e diferentes solventes, sendo estes: o monômero de estireno, acetona P.A e álcool etílico absoluto (99,5%). Os tratamentos foram avaliados tanto para confecção de blocos quanto na fabricação de lâminas delgadas. Além disso, avaliação da qualidade da impregnação na confecção dos blocos de solo foi feita a partir dos parâmetros: odor, cor, volume de material gasto, solubilidade do pigmento, polimerização e secagem, corte, número de reimpregnações e custos dos reagentes. Também foi verificado na qualidade final do produto, a quantidade de poros não impregnados e uma avaliação qualitativa das lâminas. Verificou-se que a resina poliéster arazyn 1.0#08 tendo a acetona como solvente apresentou resultados satisfatórios na impregnação de solos, na confecção de blocos polidos e lâminas delgadas, para ambos os tipos de solo estudados. Porém, não foi capaz de substituir totalmente o estireno, contudo promove uma redução significativa do uso do estireno devido a possibilidade de substituição por acetona. Por outro lado, o tratamento com resina epóxi apresenta grande limitação da qualidade das lâminas delgadas não sendo obtidos resultados satisfatórios no produto final. No entanto, pode ser considerado uma alternativa para trabalhos que analisam apenas blocos polidos, uma vez que apresentou resultados positivos, em todas as texturas de solo que foram impregnadas. / Micromorphology uses optical microscopy and associated techniques to study soil\'s components at the microscopic scale for undisturbed samples. This technique allows identification of features related to soil processes and formation that can be applied to soil\'s genesis, physics, mineralogy, microbiology, among others. To perform these analysis, it is commonly used rigid materials to produce thin sections from undisturbed soil samples by the soil impregnation process. However, the plastic resins (e.g., polyester resin) containing the styrene monomer is considered toxic for human health. In addition, the wastes production from toxic materials may pose environmental risks. In Brazil, for instance, there are few laboratories performing the impregnation process of soil samples for micromorphological analysis, probably because of the reagents toxicity. Thus, given the importance of micromorphology for Soil Science, it is critical to seek other alternatives for soil micromorphology analysis. These alternatives must be economically feasible, chemically safe, non-hazardous for human health, attending environmental compliances, and contributing to sustainable development without compromising the product quality. Consequently, our work aimed to eliminate or replace the use of styrene monomer in the soil impregnation process by similar substances less toxic to the handling and evaluate the use of polyester resin solutions and epoxy resin solutions with different diluents (styrene, acetone and alcohol) in the impregnation process of soil samples (clayey, medium and sandy texture). We conducted an investigation using two resins, as follows: Arazyn 1.0 # 00 polyester resin, Arazyn 1.0 polyester resin # 0.8 and Epoxy resin Epoxiglass 1504; and the following solvents: styrene monomer, acetone and absolute ethyl alcohol (99.5%). We evaluated both blocks confection and thin sections manufacture. We also assessed the impregnation quality during soil blocks preparation based on the following parameters: odor, color, amount of material spent, pigment solubility, polymerization and drying, cutting, number of reimpregnations, and reagent costs. Within the product quality we also evaluate the non-impregnated pores quantities besides a qualitative evaluation of the thin sections. We found the polyester resin Arazyn 1.0 # 08 (containing acetone as a solvent) had satisfactory results in the impregnation of soil samples for both block soils and thin sections using the three soil texture types. Even though this treatment significantly decreased the use of styrene due to the potential substitution for acetone, we were unable to completely replace the styrene. On the other hand, the epoxy resin demonstrated limitations regarding the thin section quality, so that the results were not satisfactory for the final product. The epoxy resin can be considered a good alternative for analyzing soil blocks solely, since it presented positive results for the three impregnated soil textures.

No description available.

For decades, researchers have been working to better understand the effects of acid and metal toxicity to aquatic organisms and to develop ways to effectively mitigate these detrimental effects. Acid mine drainage (AMD) causes environmental pollution that affects many countries having historic or current mining industries. Both surface and underground mining have the potential to create AMD and therefore adversely affect the local and adjacent environments. Through malignant mining and farming practices, damming rivers and the changing climate, surface freshwater resources are rapidly being reduced in Australia. Mine pit lakes offer a large freshwater resource that if managed correctly may sustain significant environmental, social and economic benefits from selected end uses for the future. However, assessment of mine pit lakes needs to be achieved to validate end use options. The Collie Basin located in the southwest of Western Australia is a coal mining area with many abandoned open cast mines (OCM). Some of these OCM have filled with water forming mine pit lakes that are affected by AMD. The result is large freshwater bodies with moderate to high concentrations of metals and a low pH. High concentration of metals combined with low pH is of environmental concern to both the aquatic and terrestrial ecosystem. Nevertheless, remediation techniques for AMD are available and applicable to these acidic lakes. However, the lakes in the Collie Basin are low in sulphatic compounds, therefore, restricting the use of the most common remediation treatment of bioremediation with sulphate reducing bacteria. Three remediation treatments were assessed for there efficacy in toxicity amelioration to three mine pit lakes. The treatments assessed were Limestone addition, phosphorus addition and a Rapid Catalytic Oxidation (RCO) treatment. / Toxicity assessment was achieved by means of comparing physico-chemical data to guideline trigger values and biological assessment. Biological assessment was achieved with three commonly used but ecologically and geographically relevant species. The bioassay species were the alga Chlorella protothecoides, the crustacean Ceriodaphnia cf dubia and the protozoa Tetrahymena thermophila. Aquaculture is being trialled adjacent to one of the pit lakes in limestone treated mine pit lake water. Therefore, the aquaculture fish species Bidyanus bidyanus early life stages were also used to assess residual toxicity from treated mine pit lake water. Limestone remediation of pit lake water demonstrated good reduction of dissolved metal concentrations with the exception of Zn and the ability to increase pH to circum-neutral. Biological assessment of limestone treated pit lake water showed that toxicity was removed to the three bioassay species and to the aquaculture species B. bidyanus early life stages. A larger field- scale mesocosm experiment with limestone treatment in situ is recommended. Assessment of the mesocosm experiment with biological and chemical analysis will confirm the efficacy of this treatment for full scale use.

Abstract not available