<p>U okviru doktorske disertacije opisane su jedinstvene fiziĉko-hemijske karakteristike<br />grupe supstanci benzena, toluena, etilbenzena i ksilena koje pripadaju istraživanjima<br />najnovijeg trenda nauĉne javnosti. Posebno su opisane perzistencija i<br />pseudoperzistencija, transport, distribucija i negativan i toksiĉan uticaj na zdravlje<br />ĉoveka i životnu sredinu. Sprovedena su eksperimentalna istraživanja zavisnosti<br />koncentracionih nivoa BTEX jedinjenja u izduvnim gasovima i operativnih parametara<br />eksperimentalnog motora SUS. Na osnovu dobijenih rezultata eksperimentalnih<br />istraživanja definisan je emisioni model BTEX jedinjenja simulacijom kretanja<br />putniĉkog automobila Fiat Punto Classic u skladu sa NEDC ciklusom koji na<br />odgovarajući naĉin reprezentuje standarde uslove vožnje u evropskim gradovima.</p> / <p>In this thesis, the unique physicochemical characteristics of a group of substances<br />consisting of benzene, toluene, ethylbenzene and xylene have been described.<br />Special emphasis has been placed on their characteristics of persistence and pseudopersistence,<br />transport, distribution and the negative and toxic influence on human<br />health and the environment. The experimental research of the interdependence of the<br />concentration levels of BTEX compounds in the exhaust gases and the operational<br />parameters of the experimental IC engine has been conducted. Based on the<br />experimental research results, the emission model of the BTEX compounds has been<br />defined by a simulation of movement of a Fiat Punto Classic passenger car in<br />accordance with the NEDC cycle, which appropriately represents the standard driving<br />conditions in European cities. Research conducted within the thesis represents the<br />newest trend of investigation in the scientific world.</p>

Contaminant transport modeling is being used more often at petroleum hydrocarbon contaminated sites in an attempt to aid engineers in evaluating the feasibility of natural attenuation as a remediation alternative in groundwater systems. In this research, a three-dimensional sequential electron acceptor computer model, SEAM3D, developed by Waddill and Widdowson (1997) was used to simulate contaminant transport at a leaking underground storage tank site in Beaufort, South Carolina. Gasoline containing benzene, toluene, ethylbenzene, and xylene (BTEX) as well as methyl tertiary butyl ether (MTBE) leaked into the subsurface at the site late in 1990, and monitoring of the water table elevations and contaminant concentrations began in 1993. Using the field data, the groundwater flow model MODFLOW was used to develop and calibrate a flow model for the Laurel Bay site using GMS (Groundwater Modeling System) v2.1. MODFLOW was coupled with the SEAM3D contaminant transport model, and the available concentration levels were used to calibrate, verify, and validate the site model. The results indicated that SEAM3D simulated complex, interconnected processes including biodegradation, and the transport of multiple hydrocarbon compounds, electron acceptors, and end products over time and space at a specific petroleum hydrocarbon contaminated site. Once the model was calibrated and verified, the model output was used to study the changes in contaminant mass distribution, contaminant mass loss, and mass loss rates for each terminal electron accepting process (TEAP) over time. It was found that the natural attenuation capacity of the aquifer was insufficient to stabilize the plume and prevent it from reaching the defined point of contact (POC). Contamination was shown to have reached the POC by 1994, just four years into the simulation. Results indicated that despite oxygen limitation within the BTEX plume, aerobic biodegradation was responsible for the greatest amount of mass loss, close to 70 %, relative to the sum of the anaerobic processes after 20 years. / Master of Science