Summary and conclusions: environmental effects of North Sea oil and gas developments

Abstract

From the Abstract: “Offshore platforms are a source of chronic pollution from production water, but in recent years there has been a marked increase in the use of oil-based drilling muds and it is estimated that 20 Mt per year of petroleum hydrocarbons are added to the sea in oil-contaminated drill cuttings. The effect of these additions has been studied in the laboratory, in mesocosms and in field surveys which, together yield a consistent picture. Within a radius of a few hundred metres of a platform there is impoverishment of the benthic fauna. Closest to the platform the production of anoxic conditions through smothering and the activity of sulphide-producing bacteria is probably more significant than the toxic effect of the oil-based muds. Outside this immediate zone of impact, the oil results in organic enrichment and enhanced populations of some of the fauna. The total area affected is, in the context of the North Sea, minuscule. There is no evidence that plankton is materially affect and the success of commercial fisheries dependent upon the plankton crop is more influence by fishery practices than by any other factor. Seabird populations, about which there was formerly