Physical Sciences and Mathematics Commons^™

Coastal Watershed Monitoring And Management: Geomorphology, Geochemistry, And Hydrologic Modeling Of Los Peñasquitos Creek, Ca, Ravleen Khalsa-Basra

Theses

Rivers in semi-arid climates are directly influenced by local geographic and hydrologic conditions and impacted by modifications to hydrology via urbanization. Changes can influence erosion, morphology, habitat sustainability, and watershed health. In highly urbanized southern California coastal regions, these rare open spaces provide vital ecosystem services. Los Peñasquitos Creek in San Diego County is one such watershed. Using stream surveying and laboratory methods we quantified channel characteristics, grain size distribution, total metal concentration [M], organic carbon (%OC), and phosphate to longitudinally characterize the creek for improved management. Results identified three distinct reaches in the watershed (upper, middle, lower). Downstream, depth …

Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright

Theses

Anomalously elevated arsenic concentrations occur at an abandoned artisanal mine site in an open space recreational park in urban San Diego County, California. Although mining at the site ceased 100 years ago little to no remediation efforts took place leaving shafts, adits, waste piles and derelict infrastructure accessible by inquisitive hikers and adventurers frequenting Black Mountain Open Space Park. This study evaluates the geochemical mechanisms of As transport downgradient from the mine and examines the contribution of both climate and urbanization on the restriction of As mobility. Sediment As concentrations reach 2,320 mg/kg (483 times background crustal concentrations; n=73) along …

Applications Of Pure And Recycled Polymeric Micronanofiber For The Removal Of Oil Spills, Afra Gharib Khamis Al-Blooshi Al-Blooshi

Theses

Cleaning oil spills is a universal concern due to its environmental impact. The aim of this study is to study the effectiveness and applications of pure and recycled polymers in clean-up and the recovery of crude oil from oil spills. In this study, micro-nanofibers of analytical-grade and commercial polystyrene samples were prepared by electrospinning technique. Fiber size distribution was shown to vary with the electrospinning parameters and type of polymer. Fibrous sorbents prepare hereafter were investigated for their efficiency in removing oil spills. Results showed a variation in the sorption capacities of the fibers to various types of crude oils …

Toxicodynamics And Biotransformation Of Azaspiracids Incorporating Liquid Chromatography-Tandem-Mass Spectrometry (Lc-Ms/Ms) Techniques., Daniel O'Driscoll

Theses

Azaspiracids (AZAs) are a family of lipophilic polyether marine biotoxins, that have caused a number of human intoxication incidents in Europe since 1995, which was the first incident reported following the consumption by consumers of intoxicated shellfish {Mytilus edulis). This class of phycotoxins has been responsible for extended closures of shellfisheries in various locations around Europe, where levels of AZAl-3 are regulated in shellfish. Since their discovery in 1995, AZAs have become the focus of extensive research, resulting in the discovery of numerous analogues. Only AZAl and AZA2 have been found in phytoplankton and all the other analogues are believed …

The Application Of Lc-Ms Technologies For The Detection Of Triazine Herbicides In Water, Michael Cahill

Theses

The triazine herbicides, including, simazine (6-chloro-N,N’-diethyl-1,3,5-triazine-2,4- diamine), atrazine (2-chloro-4-ethylamino-6-isopropylamino-l,3,5-triazine) and cyanazine were developed as selective weed killers. Their design function is to disrupt the photosynthesis of broad-leafed plants. In the intensive production of grasses (e.g. wheat, cereals, etc.) broad-leafed plants growing in the grass production area are economically costly, competitors with the grasses for nutrients; their removal is facilitated by triazines herbicides and simazine and atrazine are the predominant compounds used. Significant amounts of triazine herbicides are consumed by the agricultural industry each year. However, due to the indiscriminate use of pesticides/herbicides, traces of herbicides have been found in run-off …

Solvent Targeting, Avoidance And Recovery Trials (Start), Kealan Allen

Theses

Solvent is the largest-volume raw material used at Janssen Pharmaceutical (Ire) Ltd. Over 2.2 million m³ were used in 2004. The top 13 solvents make up 99% of this amount. There are two main uses for solvent on site, processing and cleaning. Processing uses 55% of the total solvent used on site, cleaning uses the remainder.

Waste solvent forms the majority of the hazardous waste produced at Janssen. Three treatment options exist at present for this waste: incineration, recovery for reuse and energy recovery. All of the hazardous waste produced on site must be exported for these treatment options, …