Soil and Water Contamination Levels in an Out-of-Service Oil Distribution and Storage Station in Michoacan,Mexico

An oil distribution and storage station (ODSS) in Michoacan, Mexico was active from 1963 to 1999. Out-of-service since then, it is now subject to a dismantling process. From the results of this study it was concluded that ODSS soil is contaminated mainly with TPH, BTEX, MTBE, Pb, Fe, Cr, and Zn. Total petroleum hydrocarbons and metal contamination is clearly localised in three main area: in front of the TV-284 storage tank, along the area where the train railway was once situated, and the zone near the pumping house. Pb was detected in groundwater in concentrations higher than 0.025 mg l^-1. A health risk assessment (HRA) was carried out. From the HRA results, it was proposed to reduce the benzene, iron, MTBE, lead, and xylene concentrations from their current values to 0.0072, 6,000, 0.21, 400, and 100 mg kg^-1, respectively. Total petroleum hydrocarbon concentration must be reduced from 59,000 to 2,000 mg kg^-1. Remediation of the ODSS soil with regard to the high TPH, MTBE, Pb, Cr and benzene concentrations appears feasible and will allow the use of the old ODSS with new soil uses at middle and long term.