The distribution of hydrocarbons on the east and south-west Irish coasts and in the Liffey Estuary

The nature and spatial distribution of hydrocarbons were studied in several Irish coastal and estuarine sites, using surface sediments and Mytilus edu lis as environmental indicators. The hydrocarbon load of the Liffey Estuary was assessed in detail. The range of hydrocarbon levels varied from those below the detection limit to chronic petroleum contamination. The petroleum origin was determined by the presence of typical petroleum characteristics , i.e. high concentrations, unresolved complex mixtures and an odd/even car bon ratio (carbon preference index (CPI)) of approximately 1.0. Low concent rations of hydrocarbons in coastal areas contrasted with elevated concentra tions of petroleum hydrocarbons in estuarine areas subject to anthropogenic activity. Liffey sediments were heavily contaminated. Mussels were the mor e effective indicator of hydrocarbon pollution at sites where the sediments were coarse and of low organic matter content.