TPH-contaminated Mexican Refinery Soil: Health Risk Assessment and the First Year of Changes

Abstract

The soil of a coastal Mexican refinery is quite contaminated, especially by hydrocarbons, with detected concentrations up to 130000 mg kg(-1) as TPHs (total petroleum hydrocarbons). The main sources of contamination are pipelines, valves, and old storage tanks, besides the land disposal of untreated hydrocarbon sediments derived from the cleaning of storage tanks. A health risk assessment (HRA) was carried out in order to measure the risk hazard indexes and clean-up standards for the refinery soil. HRA suggested the following actions to be taken: benzene concentrations must be reduced in eight of the 16 studied refinery zones to 0.0074-0.0078 mg kg(-1). Also, vanadium concentration must be reduced in two zones up to a concentration of 100 mg kg(-1). In only one of all of the studied zones, benzo(a)pyrene concentration must be reduced to 0.1 mg kg(-1). After 1 yr, TPHs showed a diminution of about 52%. Even though TPHs concentrations were variable, during 1999 the average concentrations were as much as 15.5 times the goal concentration. For year 2000, TPHs concentrations were only 7.4-fold the proposed value. For the 1999-2000 period, PAHs (polycyclic aromatic hydrocarbons) concentrations decreased by 82%. Some PAHs with 2, 3, 4, and 5 aromatic rings were removed up to 100% values.

Operation of a 27‐m3 biopile for the treatment of petroleum‐contaminated soil

“…Note that this TPH level is more than ten times the concentration of the 100-m 3 biopile previously reported (Iturbe et al, 2004a). Design and operation issues are discussed, including microbiological and respirometric aspects.…”

“…The soil is contaminated mainly by TPH-diesel and TPH-gasoline fractions (see Exhibit 1), BTEX, PAHs, and some metals (Iturbe et al, 2004a).…”

“…In a previous work (Iturbe et al, 2004a), the authors evaluated the treatment of a soil contaminated with about 4,600 mg/kg of TPH, and four PAHs (phenanthrene, naphthalene, fluorene, and pyrene) at different concentrations (total PAH concentration of 13.07 mg/kg). The authors employed a 100-m 3 biopile to treat the soil in 66 days.…”

Ex-Situ Remediation Technologies for Environmental Pollutants: A Critical Perspective

“…They achieved an approximately 27 % increase in metal removal by the use of biodegradable chelates and permeable barriers. Iturbe et al ( 2004 ) conducted a fi eld experiment to remediate an out-of-service oil distribution and storage station contaminated with PAHs, BTEX, MTBE, diesel and gasoline in Mexico by using biopile and soil washing methods between 1966 and 2000. Washing approximately 1600 m 3 soil using non-ionic surfactant and biopiling (operated for 66 days) removed more than 93 % of the total contaminants in 500 days.…”

Source Apportionment of Petroleum Hydrocarbon Contamination in Karst Fissure Groundwater

“…Starting from the 1970, some studies had confirmed that the anthropogenic sources of petroleum hydrocarbons pollutants in groundwater, including the domestic and industrial wastes, the combustion of some fuels, as well as the transformation of non-hydrocarbon natural products into hydrocarbon-forming rocks [5]. Soils in the coastal areas of Mexico are severely polluted caused by refineries, and the main sources of pollutants result from the disposal of oil pipelines, valves, old tanks and untreated hydrocarbon deposits from cleaning tanks [6]. More than 30% petrol stations and most of the refineries, chemical plants in Britain existed the phenomena of leakage and arbitrary emission, leading to the serious petroleum hydrocarbons contamination of groundwater in gas station and petrochemical enterprises [7].…”