Extraktion och analys av PAH : En studie kring kontamineringshastigheten i mark

• Main Author: Nilsson, Karolina
• Format: Others
• Language: Swedish
• Published: Högskolan i Gävle, Miljövetenskap 2020
• Subjects: PAH; Ultraljudsbad; HPLC; Polycykliska aromatiska kolväten; PAH-16; Other Chemical Engineering; Annan kemiteknik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-33260

Polycyclic Aromatic Hydrocarbons (PAH) are an organic compound group consisting of cyclic molecules of two or more condensed benzene rings. All PAH are toxic to living organisms and their toxicity increases with increasing molecular weight. PAH are classified as environmental toxins but are currently not prohibited from emitting. The absence of a ban is based on the fact that the emission sources are difficult to eliminate. The present emissions mainly stem from wood burning, where heating is the primary purpose. Historically, PAH have also been released from various industrial activities. PAH are formed by incomplete combustion of organic matter at temperatures around 600°C. Thousands of tonnes are released annually and deposite over time in soils. The larger compounds become relatively immobile due to their unpolar properties. The longer the deposition takes place, the harder the PAH bind to the organic matter in the soil and cause that the decontamination work becomes more difficult over time. The remediation work is costly and because emissions are ongoing, this means that land that has been cleaned up in the long term will be re-contaminated.   The original purpose of this study has been to investigate the PAH contamination rate in a specific soil area. Originally, the purpose was also to investigate which factors affect the development of the contamination rate and potentially make the calculation work more difficult. Hypothetically, an average contamination rate could be obtained by combining measured concentrations of the PAH-16 standard from previous measurements at the same location with a current concentration from the same area plotted against time. However, measured values ​​from repeated measurements are missing. Thus, the recontamination rate at present cannot be calculated, at least not by this method. As part of future studies, it would be advisable to start taking soil samples, analyzing the PAH-16 and storing the values ​​in an existing environmental database in order to be able to monitor concentrations in soils over time. Part of the problem with this is that it is difficult to take a test at exactly the same location twice and concentrations can differ markedly even in small areas. A method for the precise selection of sampling site would therefore be appropriate to develop. The study describes the problems that are found in connection with extraction and analysis of PAH. In the extraction and analysis work itself, the most critical elements have been shown to be to extract all PAH substance from the soil sample and subsequently to avoid laboratory-related losses and to detect all compounds in the analysis. The study also reports on a number of factors that make it difficult to calculate the recontamination rate in the absence of measurement series missing.