Prioritisation of Crude Oil Contaminated Sites to Inform Risk Decision Making Using Soil Quality Index

Abstract

Crude oil contaminated sites delineation by soil quality index (SQI) is presented. This study used SQI proposed by the Canadian Council of Ministers of the Environment (CCME) to delineate three genuinely petroleum-contaminated sites in the Niger Delta, Nigeria to prioritise sites to inform risk decision making and/or remediation. In assessing the potential impact on human health risks at the contaminated sites, soil screening levels (SL) and gas chromatography-mass spectrometry (GC-MS) reference concentrations of total petroleum hydrocarbon (TPH) fractions with higher exposure potential (nC10-nC16, nC16-nC35, nC35-nC40), and risk indicator compound (benzo[a]pyrene) were used in calculating the SQI scores. The sites were assessed by scoring them on a scale spanning from 0 to 100, where 0 indicates a very high level of human health risks and 100 indicates no action is required. The following results were obtained: (a) Site 1, SQI=36.9. This indicates high priority for remediation; (b) Site 2, SQI=49.1, which implies there is high priority for remediation and (c) Site 3 (SQI=45), which means site 3 requires high priority for remedial action. Thus, SQI method can be used to prioritse crude oil contaminated sites to enhance risk classification and decision-making and provide further insight to the contaminated land sector.