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Farmworkers and their families may experience increased levels of agricultural pesticides in their homes due to both (1) take-home/soil track-in on shoes, clothes and skin, and (2) air infiltration from nearby agriculture fields via agricultural pesticide drift in the vapor phase or adhered to resuspended soil particles. This dissertation estimates the relative contributions o the take-home/soil track-in and air infiltration pathways of agricultural pesticides into homes, as well as identifies the risk factors for increased in-home agricultural pesticide levels for farmworkers and their families living near agriculture fields. Samples of outdoor air, yard soil, and house dust from 21 farmworkers' homes in Yuma County, Arizona were collected and analyzed for a suite of agricultural pesticides. To capture household information, such as behaviors, demographics, and housing structure, a participant questionnaire was administered at the time of the sampling. A pesticide transport model was developed, evaluated, and applied to quantify relative contributions of the air infiltration and the take-home/soil track-in pathways of agricultural pesticides into the house dust of the farmworkers' homes. To explore a wide-range of potential risk factors for increased agricultural pesticide levels in the homes, traditional statistical methods and Classification and Regression Tree (CART) analyses were used. The results of this study, found that the air infiltration pathway contributes to over 90% of some agricultural pesticides in the house dust found in the farmworkers' homes. In addition, among the influential risk factors for increased in-home agricultural pesticide levels was the home being a closer distance to an agricultural field, as well as the home having carpeted floors, more farmworkers per square footage of the home, and less months of heating and cooling the home. It is suggested that future intervention efforts to reduce in-home agricultural pesticide levels put more emphasis on targeting the air infiltration pathway, and take into consideration relevant risk factors for increased pesticide levels in the home.

The East Shetland Basin is a superb natural laboratory in which to study the role that normal fault growth and linkage has in determining petroleum prospectivity. Use of several high density 3D seismic volumes and over 250 boreholes permits key aspects of the Late Jurassic rift and its Permo-Triassic precursor to be analysed and its role on hydrocarbon trap formation, reservoir distribution and migration determined. The regional interpretation has revealed the generation of a North Sea archipelago of Upper Jurassic islands, the role of relay ramps in controlling syn-rift sediment dispersal patterns and the impact of normal faults of the later episode crossing and offsetting those generated by the earlier phase. The uplift, erosion and meteoric flushing of Upper Jurassic and older strata within the exposed fault blocks could potentially have huge consequences for the Brent play by enhancing reservoir properties and hence, help identify new play opportunities down-dip of major structures. Fault control on sediment dispersal can also be documented in a more localized study on the Cladhan Field, the site of a pronounced basin-margin relay ramp. This recent discovered set of syn-rift density flows illustrates how the development and distribution of depositional gradients and transport pathways form subtle play types. The Cladhan area is just one of several locations throughout the East Shetland Basin where the interaction of multiple rift phases is influential in the structural feedback after the Upper Jurassic rifting event. The delicate interaction and reactivation of underlying structural trends creates a series of multi-tiered fault block systems which can define several aspects of a petroleum system, depending upon the strike, polarity and level of reactivation of faults from one rift to another. The observations of fault growth and linkage in the Northern North Sea may provide generic lessons that help in determining petroleum prospectivity in other hydrocarbon rift basins (e.g. E. Africa and the N. Atlantic seaboard of North America).

Historical change in the geomorphology, hydrodynamics, and surficial sediment of the tidal delta system of Tauranga Harbour are investigated with the general aim of analysing The general aims of this thesis are: firstly to analyse historical changes to inlet delta system geomorphology using historical hydrographic charts, secondly, to conduct hydrodynamic numerical modelling using historical bathymetries to access changes in peak spring flow and potential net tidal sediment transport, and thirdly, to analyse historical changes in surficial sediment and bedforms. Geomorphic change was investigated through plotting difference in bathymetry graphs and conducting cross sections taken from digisitied bathymetries obtained from historical hydrographic charts from 1852, 1879, 1901, 1927, 1954 and a modern bathymetry from 2006. Two-dimensional hydrodynamic numerical modelling was conducted to investigate the changes in peak tidal current flow and potential net sediment transport between 1852 and 2006. Changes in surficial sediment patterns were determined through completing a side scan sonar survey with associated sediment samples for ground truthing of grain size and underwater videography to gather surficial shell coverage information. This was used to produce a surficial sediment coverage map which was compared to historical studies Major geomorphological findings include that the shipping channel appears to have induced minor change in the geomorphology of the FTD but such changes are similar to those identified in the historical bathymetries of 1852, 1879, 1901, 1927, 1954 prior to dredging. Significant changes have occurred on the ETD, with the majority of the ETD showing scour of 1 m while the terminal lobe has extended seawards. This is associated with historical (since 1852) narrowing of the inlet from Panepane Point to Mt Maunganui by ~ 900 m. Hydrodynamic numerical modelling has shown a significant increase in potential net tidal sediment transport in the Cutter Channel due to dredging, while the Maunganui Roads Channel shows a reduction of net potential tidal sediment transport that is associated with the dredging of this channel. The area surrounding Panepane Point undergoes significant increases and decreases in net potential tidal sediment transport both before and after dredging Investigation of the surficial sediment patterns over the FTD and ETD from sidescan sonar and bottom samples show that between 1983 and 2007 there has been a northwards extension of the area of major shell (greater than 50 %) converge in the main ebb channel as well as reduction in major shell converge in flood tidal delta ebb shield region. The Maunganui Roads Channel changes from sitly sands to medium and fine sands.

Intra-archipelago waterways, including tidal strait networks, present a complex set of barriers to, and conduits for sediment transport between marine basins. Tidal straits may also be the least well understood tide-dominated sedimentary environment. To address these issues, currents, sediment transport pathways, and seabed sedimentology & geomorphology were studied in the central Salish Sea (Gulf and San Juan Islands region) of British Columbia, Canada and Washington State, USA. A variety of data types were integrated: 3D & 2D tidal models, multibeam bathymetry & backscatter, seabed video, grab samples, cores and seismic reflection. This dissertation included the first regional sediment transport modelling study of the central Salish Sea. Lagrangian particle dispersal simulations were driven by 2D tidal hydrodynamics (~59-days). It was found that flood-tide dominance through narrow intra-archipelago connecting straits resulted in the transfer of sediment into the inland Strait of Georgia, an apparent sediment sink. The formative/maintenance processes at a variety of seabed landforms, including a banner bank with giant dunes, were explained with modelled tides and sediment transport. Deglacial history and modern lateral sedimentological and morphological transitions were also considered. Based on this modern environment, adjustments to the tidal strait facies model were identified. In addition, erosion and deposition patterns across the banner bank (dune complex) were monitored with 8-repeat multibeam sonar surveys (~10 years). With these data, spatially variable bathymetric change detection techniques were explored: A) a cell-by-cell probabilistic depth uncertainty-based threshold (t-test); and B) coherent clusters of change pixels identified with the local Moran's Ii spatial autocorrelation statistic. Uncertainty about volumetric change is a considerable challenge in seabed change research, compared to terrestrial studies. Consideration of volumetric change confidence intervals tempers interpretations and communicates metadata. Techniques A & B may both be used to restrict volumetric change calculations in area, to exclude low relative bathymetric change signal areas. / Graduate / 2018-12-07