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The identification and subsequent treatment of contaminated land and groundwater is currently being regulated by the Environment Agency. The closure of gasworks sites during the late 1960s left areas of land contaminated with undesirable residues of the manufactured gas process, which were left to cause further pollution by leaching into surface and groundwater. The techniques available to remediate these contaminated media are numerous, but most tend to suffer from at least one major disadvantage, usually time or cost.

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Land contamination by petroleum hydrocarbons is a widespread and global environmental pollution issue from recovery and refining of crude oil and the ubiquitous use of hydrocarbons in industrial processes and applications. Sustainable treatment of hydrocarbon-contaminated industrial land was considered with reference to seven published works on contaminated railway land including the track ballast, crude oil wastes and contaminated refinery soils. A methodology was developed to assess the level hydrocarbon contamination of track ballast (Anderson et al., 2000) and in Anderson et al. (2002, 2003) solvent and surfactant cleaning of ballast was investigated and potential environmental impacts of the processes examined. Optimisation of ex situ bioremediation of diesel-contaminated soil (Cunningham & Philp, 2000) demonstrated the efficacy of the addition of microorganisms (bioaugmentation) to enhance diesel biodegradation rates at field pilot scale. This work motivated a further study that examined a novel aeration approach incorporating ventilator turbines (cowls) for soil biopiles (Li et al., 2004). An optimised ex situ bioremediation for crude oil wastes was developed in Kuyukina et al. (2003) which demonstrated the efficacy of bioaugmentation and the application of biosurfactants. The final study investigated the potential application of biosurfactants to in situ remediation (Kuyukina et al., 2005) in laboratory soil columns contaminated with crude oil. The collected works are informative to those seeking to remediate hydrocarbon-contaminated industrial land and the sustainability of the approaches was considered.

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<p>This thesis compares different methods for risk assessment of a creosote contaminated site in Vansbro, Dalarna. In a complementary study the importance of using representative data for calibration and validation of stationary groundwater models is discussed. The time dependency between surface water levels and groundwater levels on the site in Vansbro is evaluated by step response analysis. The results show that the groundwater levels reflect only long-term variation in the surface water levels. Hence the use of such long-term means for calibration and validation of the stationary groundwater models is the only theoretically defendable alternative.</p><p>As a first step in the comparison of risk assessment methods the degree of contamination is evaluated on the basis of generic guideline values for contaminated soils, developed by the Swedish Environmental Protection Agency. The guidelines specifically developed for contaminated petrol stations are also taken into consideration. Secondly, a site-specific evaluation is carried out. The transport of contaminants from the soil to the on-site groundwater and nearby surface water is calculated using the mathematical models behind the aforementioned guideline values. The calculated groundwater concentrations show a poor agreement with observed data and the thesis points out several possible explanations of this deviation. A sensitivity analysis is carried out and the influence of biodegradation during the transport in the aquifer is evaluated. The results indicate that the deviation between observed and calculated groundwater concentrations cannot be explained by the absence of biodegradation in the mathematical models, but rather by other simplifications and uncertainties in estimated model parameters.</p><p>Finally, a risk assessment is made on the basis of observed groundwater concentrations instead of observed soil concentrations as in the assessments above. Observed groundwater concentrations are compared with guideline values for groundwater on contaminated sites. The risk of negative environmental effects in the surface water is evaluated based on the estimated inflow of contaminated groundwater and its concentration of contaminants. The inflow is estimated from the interpolation of observed groundwater levels as well as with two numerical groundwater models of varying hydrogeological complexity: a three-dimensional flow model developed in Visual MODFLOW and a two-dimensional flow model developed in TWODAN. The models are compared with respect to the calculated inflows of contaminated groundwater into the surface water body as well as their ability to reproduce observed groundwater levels. The results indicate that the differences between the models, with respect to the calculated inflows, are of lesser importance to the risk assessment in comparison with the uncertainties associated with other parameters. The choice to base the assessment on observed contaminant concentrations in either the soil or the groundwater is shown to be of crucial importance.</p> / <p>I detta examensarbete jämförs olika metoder att bedöma de hälsomässiga och miljömässiga risker som föreligger med ett kreosotförorenat markområde i Vansbro, Dalarna. I en kompletterande undersökning belyses vikten av att stationära grundvattenmodeller kalibreras och valideras mot tidskompatibla indata. Tidsberoendet mellan yt- och grundvattennivåer på området i Vansbro studeras genom stegsvarsanalys. Resultaten visar att grundvattennivåerna på området anpassar sig mycket långsamt efter rådande ytvattennivåer. Grundvattennivåerna återspeglar således medelvärden av ytvattennivåerna över en mycket lång tidsperiod. Därför är användandet av sådana medelvärden för kalibrering och validering av modellerna det enda teoretiskt försvarbara alternativet.</p><p>Som ett första steg i jämförelsen mellan olika riskbedömningsmetoder utvärderas föroreningssituationen baserat på uppmätta föroreningskoncentrationer i jorden och med hjälp av Naturvårdsverkets generella samt branschspecifika riktvärden för förorenad mark. Därefter genomförs en platsspecifik riskbedömning. Föroreningstransporten från markområdet till grundvattnet samt till ett närbeläget ytvatten beräknas med de matematiska modeller som användes av Naturvårdsverket vid framtagandet av ovannämnda riktvärden. Beräknade grundvattenkoncentrationer jämförs med uppmätta koncentrationer och resultaten visar på stora avvikelser. En känslighetsanalys utförs och inverkan av biologisk nedbrytning i akviferen utvärderas. Resultaten tyder på att avvikelsen mellan uppmätta och beräknade grundvattenkoncentrationer ej förklaras av att biologisk nedbrytning inte beaktas i modellerna utan att avvikelsen härrör från andra förenklingar och från osäkerheter i indata.</p><p>Slutligen genomförs en platsspecifik riskbedömning, motsvarande den ovan, men denna gång utifrån uppmätta föroreningskoncentrationer i grundvattnet. De uppmätta grundvattenkoncentrationerna jämförs direkt mot Naturvårdsverkets riktvärden för grundvatten på förorenade områden. Risken för negativa ekologiska effekter i ytvattnet utvärderas utifrån det beräknade inflödet av förorenat grundvatten samt dess koncentration. Inflödet beräknas överslagsmässigt utifrån interpolerade grundvattennivåer samt med två numeriska grundvattenmodeller av olika hydrogeologisk komplexitet: en tredimensionell flödesmodell uppbyggd i Visual MODFLOW och en tvådimensionell modell uppbyggd i TWODAN. Grundvattenmodellerna jämförs med avseende på det beräknade inflödet och med avseende på deras förmåga att beskriva observerade grundvattenförhållanden.Resultaten tyder på att skillnaden i det, med de olika metoderna, beräknade inflödet är av liten betydelse för riskbedömningen i förhållande till osäkerheter förknippade med övriga parametrar. Störst betydelse för riskbedömningen får valet att utgå från uppmätta föroreningskoncentrationer i antingen jorden eller grundvattnet.</p>

A brownfield is previously developed land which suffers from actual or perceived contamination due to past uses. The City of Ottawa, like many of Canada's municipalities, is faced with a significant inventory of brownfields. As the legacy of industrial activities in earlier times, these sites have become an environmental threat, blight to the community and economic loss for their owners and the City. Unlike many of Ontario's more highly industrialized municipalities, Ottawa has a less industrialized history and, as the Nation's Capital, faces unique brownfield challenges and development climate, requiring a policy approach that is tailored to the Ottawa development market. Ottawa's major brownfield sites are owned by different levels of governments and private firms, ranging from the National Capital Commission owned LeBreton Flats to the City of Ottawa owned Bayview Yards. This thesis intends to examine current development trends for brownfields, impediments and opportunities for development, assess the efficacy of current policies and provide suggestions for the improvement of the existing brownfield development planning process in Ottawa, using an applied research method. This study is developed through interviews with key informants, a collective case study analysis, a literature review and site visits. This thesis intends to study current policy and provide recommendations to improve Ottawa's approach to brownfield development. The City of Ottawa has developed a Brownfield Community Improvement Plan, featuring multiple grant programs which has proved to be successful in incentivizing the development of brownfield sites which otherwise would have remained idle. However, the creation and development of this policy was a challenging process, requiring review and improvement in light of ongoing development applications. The findings of this paper indicate the policy has been successful due to its encouragement of brownfield projects which otherwise would not have occurred. In addition, case studies of Bayview Yards, CLC Rockcliffe Lands, Lansdowne Park, LeBreton Flats, 1357 Baseline Road and 300 West Hunt Club Road illustrate the pursuit of significant brownfield development projects in the City. However, despite its success, some challenges still exist which the City of Ottawa must endeavour to overcome. By tackling these challenges, the City could further aid in erasing brownfields from Ottawa's urban fabric and leave a legacy to its residents, characterized by a robust urban centre free from severe environmental contamination.

A brownfield is previously developed land which suffers from actual or perceived contamination due to past uses. The City of Ottawa, like many of Canada's municipalities, is faced with a significant inventory of brownfields. As the legacy of industrial activities in earlier times, these sites have become an environmental threat, blight to the community and economic loss for their owners and the City. Unlike many of Ontario's more highly industrialized municipalities, Ottawa has a less industrialized history and, as the Nation's Capital, faces unique brownfield challenges and development climate, requiring a policy approach that is tailored to the Ottawa development market. Ottawa's major brownfield sites are owned by different levels of governments and private firms, ranging from the National Capital Commission owned LeBreton Flats to the City of Ottawa owned Bayview Yards. This thesis intends to examine current development trends for brownfields, impediments and opportunities for development, assess the efficacy of current policies and provide suggestions for the improvement of the existing brownfield development planning process in Ottawa, using an applied research method. This study is developed through interviews with key informants, a collective case study analysis, a literature review and site visits. This thesis intends to study current policy and provide recommendations to improve Ottawa's approach to brownfield development. The City of Ottawa has developed a Brownfield Community Improvement Plan, featuring multiple grant programs which has proved to be successful in incentivizing the development of brownfield sites which otherwise would have remained idle. However, the creation and development of this policy was a challenging process, requiring review and improvement in light of ongoing development applications. The findings of this paper indicate the policy has been successful due to its encouragement of brownfield projects which otherwise would not have occurred. In addition, case studies of Bayview Yards, CLC Rockcliffe Lands, Lansdowne Park, LeBreton Flats, 1357 Baseline Road and 300 West Hunt Club Road illustrate the pursuit of significant brownfield development projects in the City. However, despite its success, some challenges still exist which the City of Ottawa must endeavour to overcome. By tackling these challenges, the City could further aid in erasing brownfields from Ottawa's urban fabric and leave a legacy to its residents, characterized by a robust urban centre free from severe environmental contamination.