Emissions waste deposit-derived

Chapter 2 contains two studies related to groundwater contamination as a result of two different anthropogenic activities. The first study (chapter 2.1) focuses on emissions derived from a leaking waste deposit landfill. The chemical characterisation as well as the identification of specific contaminants are main objectives. Further on, using a set of specific waste deposit derived marker compounds the spatial distribution as well as a time trend was characterised in order to assess the risk of the waste deposit derived effluents. 

Several xenobiotics identified in both the seepage water and the leakage water on the same concentration level were not only persistent but also specific for the waste deposit-derived emission. Hence these stable source indicators (e.g. DEET, NBBS and propyphenazone) appear to be appropriate tracers for the subsequent route of the contamination derived from the waste deposit landfill. 

PAHs from vehicle emissions constitute a minor, but measurable, source of soil PAHs (Table 25.3). The majority of highway-derived PAHs appears to be deposited within 3.8 m of the road, but the influence of the highway may extend to nearly 70 m (Johnston and Harrison 1984). The use of composted muiucipal wastes for conditioning agricultural soils is not recommended, as these contain at least nine identified carcinogeiuc PAHs (Martens 1982). 

A contamination with several C1-C4 alkylated pyrazines, cyclopentapyrazines and pyridines was discovered in the second extracts. These compounds are described in detail as primary products of the Maillard reaction, the non-enzymic browning reaction between carbohydrates and amino acids (e.g. Mulders, 1973 Chen et al., 1998). Therefore, the occurence of these specific pyrazines and pyridines suggested either contemporary degradation processes of carbohydrates with amino acids or ammonia within the deposit landfill or the emission of waste derived Maillard products generated already before deposition. 

Benzene, toluene, and their derivatives enter the atmosphere by various mechanisms such as controlled emissions from consumer industries, volatilization from waste dumps and landfill sites, intentional spraying and dusting, and from automobile exhaust. Since such compounds are moderately soluble in water, they are probably washed out of the atmosphere with rainfall, deposited in surface waters, and then evaporated back into the atmosphere. Although this recycling process may be a significant source of aromatic... 

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