Natürliche und anthropogene organische Spurenstoffe in küstennahen Meeressedimenten: Gehalte und Verteilung von polyaromatischen Kohlenwasserstoffen

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a class of hazardous substances, which as a result of pyrolytic processes become ubiquitous in the environment and accumulate in water body sediments. Their isolation, quantitation and distribution patterns are the subject of this work, which in its first part deals with method development and testing (extraction, fractionation, solvent gradients, detector settings) and an extensive literature study on PAH patterns in environmental material. The second part affords data on PAH contents and patterns found in coastal surface sediments and some other matrices (water column, shore material). Results are presented in groups according to the regional provenance of samples and are discussed with respect to sources and preservation conditions. Data rely on RP-18-HPLC for standard PAHs and additional capillary GC measurements for other polycyclic and open chain compounds. Investigated sediments originate from the German North and Baltic Seas, from the central Norwegian Voering-Plateau and two Brazilian coastal areas. PAH contents ranged from about one (subrecent fine material) to 17 000 (harbour mud) ppb (total of 13 priority compounds according to U.S. EPA). Profiles of alkyl homologues and content ratios of PAHs with sceletons of differing environmental stability allowed to differentiate between samples, but not always to clearly discern petrogenic contributions from predominantly pyrogenic PAH assemblages. Perylene, biogenic alkylhydrochrysenes and -picenes as well as long-chain aliphatics with a terrestrial signature proved to be valid indicators of input sources and depositional features; the homologue profile of long-chain n-aldehydes appeared as a potential marker for sugar cane. A larger set of PAH compounds up to MW=302 as chemical parameters and the possible existence of a diagenetic relationship between perylene and hexahydroperylene are described and proposed for future testing.