BURIAL AND BREAKDOWN OF OIL IN COASTAL DUNE SYSTEMS

摘要

In 1992 and 1994, sites where oiled beach material, resulting from tanker spills at sea, had been buried in sand dunes in 1978 were located. Analysis of samples from one site (Hemsby, Norfolk) was inconclusive but samples from Pendine in south Wales contained small quantities of hydrocarbon residues and bacterial populations capable of metabolizing catechol. Gas sampling also showed elevated concentrations of volatile hydrocarbons and carbon dioxide within the deposit compared with controls in adjacent sand dunes. Following the beaching of heavy fuel oil at Pendine in January 1994, oiled sand from the beach was deposited in the nearby dune system and a monitoring experiment was set up. Evidence of hydrocarbon degradation was found soon after deposition and was especially rapid close to the previous deposit. Progress of the oil decomposition is being monitored by collection and analysis (chemical and microbiological) of core samples and in-situ measurements of gaseous emissions. Because of problems of sand being moved by the wind and consequent concentration of oil residues on the surface, alternative methods of surface stabilization by vegetation are also being tested.