Wax has been extracted from pest formations in Europe and especially in Britain. However, little or no work have been done in the United States. The increased demand for waxes and the limited supply of domestic origin has made the study of the sources and characteristics of domestic waxes desirable. Extensive work have been done with montan wax, which is similar to peat wax, in the United States. The object of this research is to establish a suitable process for extraction of wax from pest material, and to determine the chemical and physical nature of the wax. The process may not be made economically sound, yet it may be of value to the nation's economy.

Peat soils are known to be a significant emitter of atmospheric greenhouse gasses. However, the spatial and temporal variability in production and release of greenhouse gases (such as methane) in peat soils remains uncertain, particularly for low-latitude peatlands like the Florida Everglades, as the majority of studies on gas dynamics in peatlands focus on northern peatlands. The purpose of the work outlined here is focused on understanding the spatial and temporal variability in biogenic gas dynamics (i.e. production and release of methane and carbon dioxide) by implementing various experiments in the Florida Everglades at different scales of measurement, using noninvasive hydrogeophysical methods. Non-invasive methods include ground-penetrating radar (GPR), gas traps, time-lapse cameras, and hydrostatic pressure head measurements, that were constrained with direct measurements on soil cores like porosity, and gas composition using gas chromatography. By utilizing the measurements of in-situ gas volumes, we are able to estimate gas production using a mass balance approach, explore spatial and temporal variabilities of gas dynamics, and better constrain gas ebullition models. A better understanding of the spatial and temporal variability in gas production and release in peat soils from the Everglades has implications regarding the role of subtropical wetlands in the global carbon cycle, and can help providing better production and flux estimates to help global climate researchers improve their predictions and models for climate change. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Thesis (M.Sc.), Memorial University of Newfoundland, 2000. / Bibliography: leaves 133-144.

Peatlands are areas with an accumulated layer of peat soil that are considered global stores of carbon, acting as a net sink of carbon dioxide and a net source of methane. Recent studies in coastal peatlands have shown how that a rise in sea level may contribute to the degradation of peat soils due to the inland progression of the saltwater interface, which may result in physical changes within the peat matrix that may eventually result in peat collapse. For example, earlier studies in boreal peat soils described the effect of pore dilation as a result of increased salinity in peat soils, while recent studies in Everglades peat soils showed specific salinity thresholds that may represent a permanent loss of the structural integrity of the peat matrix that may represent early stages of peat collapse. While most of these previous efforts have focused on drivers, recent work has also explored conceptual models to better understand the mechanisms inducing peat collapse. However, few datasets exists that consistently compare differences in physical properties under different in‐situ salinity conditions. In this study differences in the physical properties of peat soils across a salinity gradient along the western edge of Big Cypress National Preserve are investigated to test how differences in salinity may induce physical changes in the soil matrix. The physical properties targeted for this study include porosity, hydraulic conductivity, and carbon content. Measurements are conducted at the laboratory scale using peat cores and monoliths collected at selected locations to investigate: 1) how overall soil physical properties change spatially over a salinity gradient at the km scale moving from permanently saline to freshwater conditions; and 2) how physical properties change spatially at specific sites as dependant on vegetation boundaries and proximity to collapsed soils. This study has implications for better understanding the potential relation between physical changes of the soil matrix and the phenomena of peat collapse in the Everglades as saltwater intrusion progresses inward and alters freshwater ecosystems. Furthermore, a better mechanistic understanding of the peat collapse phenomenon can potentially help mitigate its occurrence. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 95-96. / by William Kensett Nuttle. / M.S.

This study has provided fundamental information on the fate of urine nitrogen (N) when applied to pasture soils. In this work the three pasture soils used were a Bruntwood silt loam (BW), an old well-developed (lime and fertilizer incorporated and farmed for more than 20 years) peat soil (OP) and a young peat (YP) which was less developed (farmed for about 10 years). Initial soil chemical and physical measurements revealed that the peat soils were acidic, had higher cation exchange capacities, had greater carbon:nitrogen ratios and were better buffered against changes in soil pH than the BW soil. However, the BW soil was more fertile with a higher pH. The peat soils had lower bulk densities and higher porosities. Four experiments were performed. In the first experiment ¹⁵N-labelled urine was applied at 500 kg N ha⁻¹ to intact soil cores of the three soils. Treatments imposed were the presence and absence of a water table at two temperatures, 8°C or 23° C, over 11-14 weeks. ¹⁵N budgets were determined. This first experiment showed that the nitrification rate was faster in the BW soil and was retarded with a water table present. Significant leaching of nitrate occurred at 8°C in the BW soil without a water table. This was reduced when a water table was present. Leaching losses of urine-N were lower in the peat soils than in the BW soil. Apparent denitrification losses (i.e. calculated on a total-N recovery basis) ranged from 18 to 48 % of the ¹⁵N-applied with the greatest losses occurring in the peat soils. The second experiment examined denitrification losses, over 30 days, following the application of synthetic urine-N at 420 kg N ha⁻¹ to small soil cores situated in growth cabinets. The effects of temperature (8°C or 18°C) and synthetic urine (presence or absence) were measured on the BW and OP soils. Nitrous oxide (N₂0) measurements were taken from all soil cores and a sub-set of soil cores, at 18°C, had ¹⁵N-labelled synthetic urine-N applied so that ¹⁵N-labelled nitrogen gases could be monitored. This experiment showed that the application of synthetic urine and increased soil temperature enhanced denitrification losses from both soils. Denitrification losses, at 18°C, as ¹⁵N-labelled nitrogen gases accounted for 24 to 39 % of the nitrogen applied. Nitrous oxide comprised less than half of this denitrification loss. Losses of N₂0 in leachate samples from the soil cores accounted for less than 0.1 % of the nitrogen applied. A third experiment, using Iysimeters, was performed over a 150 day period in the field. The six treatments consisted of the 3 soils with applied synthetic urine, with or without a simulated water table; each replicated three times. Lysimeters were installed in the field at ground level and ¹⁵N-labelled synthetic urine-N was applied (500 kg N ha⁻¹) on June 4 1992 (day 1). Nitrification rates differed between the soils following the trend noticed in the first experiment. As in the first experiment, nitrate was only detected in the leachate from the BW soil and the inclusion of a water table reduced the concentration of nitrate. In the BW soil, the leachate nitrate concentrations exceeded the World Health Organisation's recommended limit (< 10 mg N L-1) regardless of water table treatment. No nitrate was detected in the leachates from the peat soils but there was some leaching of organic-N (< 5 % of N added) in all the peat soil treatments. Denitrification losses were monitored for the first 100 days of the experiment. In the BW soil without a water table, N₂0 production peaked at approximately day 20 and accounted for 3 % of the nitrogen applied. In the peat soils the measured denitrification losses accounted for less than 1 % of the nitrogen applied. Apparent denitrification losses in the peats were, however, calculated to be approximately 50 % of the ¹⁵N-labelled synthetic urine-N applied. It is postulated that the difference between apparent denitrification losses and those measured could have been due to; loss of dinitrogen in leachate, protracted production of dinitrogen below detectable limits, production of denitrification gases after measurements ceased (i.e. days 100 to 150) and entrapment of dinitrogen in soil cores. Due to the apparent denitrification losses being so high, further research into this nitrogen loss pathway was performed. The fourth and final experiment measured denitrification directly using highly enriched (50 atom %) ¹⁵N-labelled synthetic urine-N. It was performed in a growth cabinet held initially at 8°C. The ¹⁵N-labelled synthetic urine was applied at 500 kg N ha⁻¹ to small soil cores of each soil type. Fluxes of N₂0 and ¹⁵N-labelled gases were measured daily for 59 days. On day 42 the temperature of the growth cabinet was increased to 12°C in an attempt to simulate the mean soil temperature at the end of the field experiment. Up to this time, production of nitrogenous gases from the YP soil had been very low. Interpretation of gaseous nitrogen loss in the YP soil was difficult due to the possibility of chemodenitrification occurring. However, in the OP and BW soils, gaseous losses of nitrogen (determined as ¹⁵N-labelled gas) represented 16 and 7 % of the nitrogen applied respectively. Nitrous oxide comprised approximately half of this gaseous nitrogen loss, in both the OP and BW soils. This work implies that urine-N applied to the mineral soil (BW) could potentially threaten the quality of ground water due to nitrate contamination through leaching. In contrast, denitrification appears to be the major loss mechanism from the peat soils, with the production of nitrous oxide being the primary focus for any environmental concern. Future work should examine the fate of the nitrate leached from the BW soil and the potential for dilution, plant uptake or denitrification below a 30 cm soil depth. A better understanding of the denitrification mechanisms could help reduce denitrification and thereby improve the efficiency of nitrogen use and reduce the output of nitrous oxide.

Ph.d.-afhandling. Den kongelige Veterinær- og Landbohøjskole, 2002. / Haves også i trykt udg.

Abstract Mercury is a global pollutant that accumulates easily in forest soils, even in remote areas. Mercury accumulated in soils can be subsequently released into surface waters causing an increased eco-toxicological and human health risk. The most toxic form of mercury to humans and wildlife is methyl mercury (MeHg), which can be formed in the environment via methylation processes. In freshwaters, MeHg is readily accumulated in fish, which are the main source of human exposure to MeHg. The determination of both total mercury and MeHg concentrations in environmental samples, such as natural waters and soils, is important in environmental risk assessment. This study involved the development of analytical methods for the determination of ultra-trace total mercury and MeHg concentrations in humic-rich natural water and peat soil samples. Each developed method was carefully optimized and validated by using real natural water and peat soil samples, certified reference materials and/or reference methods. The cold vapor inductively coupled plasma mass spectrometry (CV-ICP-MS) method developed during this study was found to be a reliable method for the determination of total ultra-trace mercury concentrations in natural freshwaters. Purge and trap gas chromatography, coupled to an ICP-MS, was used in mercury speciation analysis. Together with species-specific isotope dilution this technique proved to be a reliable method in MeHg determinations. Prior to instrumental determination, MeHg was successfully isolated from humic-rich water and peat soil samples using N2-assisted distillation. The analytical methods developed in this study were successfully applied to an investigation of the effects of forest harvesting practices on the mobilization of mercury in boreal forest catchments. / Tiivistelmä Elohopeaa pääsee ilmakehään sekä luonnollisista lähteistä (mm. tulivuorenpurkaukset ja kiviaineksen rapautuminen), että ihmisen toiminnan kautta. Elohopean viipymäaika ilmakehässä on hyvin pitkä, minkä vuoksi se voi kulkeutua kauas päästölähteestä ennen päätymistään maaperään ja vesistöihin. Ympäristössä olevasta epäorgaanisesta elohopeasta voi muodostua erittäin myrkyllistä metyylielohopeaa, joka rikastuu helposti ravintoketjussa. Metyylielohopean muodostuminen on merkittävä osa elohopean biogeokemiallista kiertoa, minkä vuoksi metyylielohopean määrittäminen näytteen kokonaiselohopeapitoisuuden ohella antaa tärkeää tietoa elohopean käyttäytymisestä ympäristössä. Tutkimuksessa kehitettiin analyysimenetelmät, joilla määritettiin ultrapieniä kokonaiselohopea- ja metyylielohopeapitoisuuksia humuspitoisista luonnonvesistä ja turvemaanäytteistä. Tutkimuksessa käytetyt näytteet oli kerätty turvemaametsien valuma-alueilta Sotkamosta. Luonnonvesinäytteiden kokonaiselohopeapitoisuuksien määrityksessä käytettiin kylmähöyrymenetelmää (CV) yhdistettynä induktiiviplasma-massaspektrometriaan (ICP-MS). Vesi- ja turvenäytteiden metyylielohopeapitoisuuksien määrityksessä elohopeaspesiekset erotettiin kaasukromatografisesti (GC) ja määritettiin isotooppilaimennus-ICP-MS:lla. Ennen GC-ICP-MS -määritystä näytteet esikäsiteltiin typpiavusteisella tislausmenetelmällä ja esikonsentroitiin ’purge and trap’ -tekniikalla. CV-ICP-MS ja ’purge and trap’ GC-ICP-MS -menetelmät optimoitiin huolellisesti sekä laiteparametrien, että reagenssimäärien suhteen. Menetelmillä saatavien tulosten oikeellisuus varmistettiin vertailumateriaalien ja/tai vertailumenetelmien avulla. Kehitettyjä analyysimenetelmiä hyödynnettiin tutkimuksessa, jossa seurattiin metsähakkuiden mahdollisia vaikutuksia elohopean huuhtoutumiseen ja metyloitumiseen ojitetuilla turvemailla.