Experience with the use of Biomarkers as Risk Indicators in Environmental Risk Assessment of oil based discharges offshore

An approach using probabilistic risk assessment for off shore oil based discharges utilising biomarkers has recently been developed (called “Biomarker Bridges). The purpose is to enable the use of biological responses (biomarkers) as Risk Indicators in procedures for Environmental Risk Assessment. The aim of the present paper is to discuss experiences gained from applying the Biomarker Bridges approach to existing data from the monitoring of an offshore oil field. The data are from the biomonitoring case study of an oil field on the Norwegian Continental Shelf. The field had no discharge of produced water at the time of the survey and sediment contaminated with drill cuttings was expected to be the main source of contamination. Applying the Biomarker Bridges approach revealed that different response patterns could indeed be detected using this method when compared to responses that would commonly be associated with produced water. Examination of the different biomarker responses in this pattern revealed effects of a different chemical discharge than produced water.