Pre-evaluation of contaminated soil for oil field reactivation in Moloacan, Veracruz, Mexico [Pre-evaluación de suelos contaminados para la reactivación de campo petrolero en Moloacán, Veracruz, México]

This document presents studies to establish an Environmental Baseline for the oil sector in 13 wells in the Moloacán Field, in Veracruz, México regarding hydrocarbons in soils. Four factors were taken into account: visual soil assessment, methods for the hydrocarbon extraction (with two methods: the Soxhlet and the Petroflag), effects on fertility properties, and heavy metals content. The results show spills in every well with a high percentage of heavy fractions (mainly polar). However, these are not entirely visible because they are below or between the rhizosphere. Also, higher concentrations of hydrocarbons were found in specific sites such as old incinerators and waste pits. In the waste pits, pollutants had contact with the aquifer. In addition, in the determination of hydrocarbons, the Soxhlet method showed better results than the Petroflag one. Likewise, a relationship between these pollutants and the negative effects on soil properties, such as the increase in densities, electrical conductivity, and sands, as well as the decrease in field capacity and clays were found. Also, pH and salinity increased when the hydrocarbons exceeded the permissible limits (>4400 mg·kg-1). Finally, metals such as Cr, V, Ba, Hg, Ni, Pb, and Cd were also found, but only Ni was found at dangerous levels for agricultural use. © 2022, Universidad Autonoma Metropolitana. All rights reserved.

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