Determination of spatial distribution in soil and investigation of air-soil phase transition of PAH and OCP compounds

Persistent organic pollutants (POPs) are organic compounds that are resistant to physical, chemical and biological degradation. POPs are generally halogenated organic compounds and are characterized as such compounds accumulating in fat mass, have low water solubility and high lipid solubility. They pose serious health problems via accumulating in fatty tissues of humans and animals through food chain due to their resistant structures which remain long period without degradation in the environment. Furthermore, these compounds create environmental and health problem in global scale due to their ability of long-range transport through air flows. POPs, such as PAHs (polyaromatic hydrocarbons), PCBs (polychlorinated biphenyls) and OCPs (organochlorine pesticides) are semi-volatile compounds. Due to their semi-volatile features, they can be transported long distances in the atmosphere before accumulation occurs. Moreover, due to their physical-chemical features, they are convenient to long-range transport both in vapor phase and in adsorbed form on particulate matters. PAHs are semi-volatile organics that consist of two or more compounds of aromatic rings. Organic pollutants in soil media like PAHs are known to be carcinogen. Nowadays, in most countries, studies are implemented in order to explore PAH pollution levels in soil and possible distribution of their sources. OCPs were widely used throughout the world and they were prohibited in most countries after their toxicity and persistency were proven. In some countries, the use of isodrin and andrin were banned since 1972, but lindane was allowed to be used only under special circumstances. Since the wide use of organic environmental pollutants such as hexachloro cyclohexanes (HCH) and dichloro dimethyl trichloroethan (DDT) in agriculture are spreading globally through moving with air and water. OCPs are known to be resistant to biodegradation, thus they can show cyclic behavior in food chain and can exceed the expected concentration at the end of chain. In this thesis, spatial distribution of OCPs and PAHs in soils both in Anatolian and in European part of Istanbul has been investigated. Sampling was made on a total of 35 points at both sides of Istanbul, having rural and urban characteristic. According to the results, samples of OCPs in 7 months, all α- HCH and DDT compounds showed dominant behaviour of acenaphthylene PAH compounds. In the pollution maps of PAHs and OCPs, PAHs showed intensive distribution focusing on industrial zone (west of Istanbul), ships stations (north of İstanbul), on shipyard (southeast) and on passage of ships in part of the Strait, and intensive distribution of OCPs were generally detected in west, southwest, in part of the Strait and in nearshore locations in Istanbul. Result of the fugacity calculations showed that light and medium molecular weight PAHs tend to evaporate in the warmer months and soil behaves as the secondary source. Soil served as reservoir for OCP compounds for the whole year.