Scholarly record

CARCINOGENIC RISK ASSESSMENT OF HEAVY METALS CONTAMINATION DUE TO ACCIDENTAL OIL SPILLS ON SOIL

PhD. student Mihaela Alexandra Stoian, Lecturer Dr. Diana Mariana Cocarta, Professor Dr. Adrian Badea, PhD. student Delia Micaela Dumitru

Abstract

Oil spills are the main cause of pollution with crude oil. Contamination with crude oil affects the environment (soil underground and surfaces, groundwater and water surface, air quality), plants, and health of animals and humans. Soil pollution with crude oil implies contamination with Polychlorinated Biphenyls, Polycyclic Aromatic Hydrocarbons, Monocyclic Aromatic Hydrocarbons and different heavy metals. The contaminated soil investigated in the framework of the present work was collected from a bioremediation platform, before that soil is undergoing to the remediation treatment. Initially, soil was excavated from a contaminated area with oil spills. The currently paper is illustrating the potential risks on human health of heavy metals from oil contaminated soil. Known heavy metals as carcinogenic to humans were analyzed: Arsenic, Cadmium, Hexavalent Chromium, Nickel and Lead. Concentrations of these heavy metals from soil samples were identified and were compared with thresholds for a sensitive and less sensitive use of soil (alert and intervention) according to the Romanian regulation in force. The values for contaminants concentration do not exceed the alert or intervention thresholds, excepting Lead with a measured concentration of 53.91 mg/kgd.w. Lead measured concentration was between alert and intervention thresholds, for sensitive use of soil (50 mg/kgd.w for alert, respectively 250 mg/kgd.w for intervention) and lower respect to the less sensitive use of soil (100 mg/kgd.w for alert, respectively 1000 mg/kgd.w for intervention). Carcinogenic risk to humans was quantified through the approach that is using the evaluation of exposure of all the relevant exposure pathways according to the considered scenarios: industrial or agricultural. For the assessment of the carcinogenic risk associated to soil contamination with heavy metals, in case of the industrial considered scenario, two pathways of exposure were considered: ingestion and dermal contact. The agricultural scenario involves the assessment of the exposure through ingestion of contaminated soil (accidentally) and ingestion of vegetable and animal products. The estimated carcinogenic risk associated to exposure to soil contaminated with heavy metals was 7.29 x 10-6 for industrial use of soil and 3.77 x 10-4 for agricultural use of soil, which exceed the acceptable value for risk of 10-6 indicated by the World Health Organization. The obtained results suggest that a remediation treatment must be applied to the contaminated soil, independently of the considered scenario.

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