The Assessment of Hydrocarbon Contamination in Contrasting Sedimentary Environments

This chapter outlines an established approach for hydrocarbon analysis in sediments, the sources of hydrocarbons in the marine environment, and the importance of understanding the sedimentary environment of deposition and the reservoir of contaminants it can represent. To supplement national monitoring programmes, government and industry have commissioned work on polycyclic aromatic hydrocarbons in several United Kingdom estuaries, including Milford Haven Waterway, Southampton Water and Sullom Voe. These areas have some of the longest-established and largest oil industry sites in the UK, and they have been monitored intensively and successfully through most of their histories as oil, gas and petrochemicals ports. However, few economically and ecologically important UK estuaries and coastal zones have a particularly long history of advanced chemical “fingerprinting” to assist monitoring the specific sources, fates and effects of sediment hydrocarbons. As such, the UK approach has not compared well with the efforts of the United States of America in terms of apportionment of contaminant sources, albeit driven in part by the latter’s focus on litigation. As well as distinguishing natural and anthropogenic inputs from background conditions, hydrocarbon fingerprinting methods can directly improve the ability to discriminate between individual hydrocarbon sources using knowledge of their composition, age and relative weathering. An understanding of the manufacturing processes and their chronology can help discriminate among multiple sources of pollutant hydrocarbons and also contribute to life cycle analysis and studies of product footprints. There is a need to track the ubiquity, fate, persistence and effects of hydrocarbons and petrochemicals in the environment. However, the use of fingerprinting faces challenges that include high cost, potentially unwelcome discovery of liability, sediment movements and patchiness, biodegradation effects on clarity of the fingerprint, and over-printing by chronic inputs from non-point sources such as air pollution and river runoff.