###### Abstract  
Oil contamination in soil from a variety of sources, including accidental leaks, industrial activities, and improper waste disposal, involves disrupting ecosystems, contaminating water, harming human health, and diminishing agricultural productivity. Bioremediation is becoming the most important method accepted as a treatment for hydrocarbon-polluted soil using indigenous microbial flora, which aims to restore soils to their pre-hydrocarbon pollution characteristics. We will follow in our article to give some examples of good practices for bioremediation of oil-polluted soils in some sites in NE Romania. In a first step, all the oil extraction wells in NW Romania were mapped, both those in operation and those abandoned, reaching 695 wells. For 7 case studies, soil profiles were taken from the vicinity of the well column and from points close to it located in the well casing, for which the concentration of total petroleum hydrocarbons was determined. Using GIS spatial interpolation techniques, the theoretical concentration of petroleum hydrocarbons in the soil was determined. The polluted soil was transported to the bioremediation station, where it was exposed to bioremediation procedures, and the period and duration until the soil was brought to the accepted parameters in terms of allowable concentrations were analysed. The time required varies between 17 and 36 weeks needed for bioremediation. Following practical applications, it can be concluded that the time required for bioremediation is directly dependent on the initial concentration of pollutants and the number of chemical and physical interventions applied to the soil. bioremediation; TPH concentration; GIS interpolation; petroleum hydrocarbon solution +
Footnote †: journal: Applied sciences  
Despite this, in 2018, Romania was the largest oil and gas producer in Central and Eastern Europe [2]. According to the National Institute of Statistics, 8.8% of Romania's total energy resources in 2020 were oil resources [2]. According to information provided by the Romanian Association of Oil Exploration and Production Companies (ROPEPCA), in 2018, Romania, there were 450 oil and gas fields and over 13,000 active wells. Of these, there are 255 commercial oil and gas fields with approximately 9450 oil wells and 830 gas wells nationwide, where oil agreements are held by a single company, 153 commercial fields with approximately 3200 gas wells, for which oil agreements are held by a single company operating in the natural gas sector; to which are added another 39 fields for which oil development-exploitation and oil exploitation agreements have been concluded, with various companies as holders. Most of these are mature fields with an exploitation period of more than 25 to 30 years [3]. A 2017 update of the register established that the number of contaminated sites in Romania's oil and gas industry is 516, and 60 sites have been classified as decontaminated. Exploration and production wells were not considered individually due to their large number. Instead, groups of wells were classified as contaminated sites if subsurface contamination was recorded at that location. Previous expert studies have identified 17 contaminated sites and 67 potentially contaminated sites in Bihor County in northwest Romania, inventoried until 2015 [4]. Petroleum hydrocarbons are a complex mixture of organic compounds with different molecular weights that affect soil properties and can have irreversible effects on vegetation, wildlife, and human health. Bioremediation measures aim to change the petroleum composition of the soil, which will lead to a change in the biological toxicity of the soil [5]. According to measurements and experiments [1] on the effects of hydrocarbon-polluted soils on seed germination of maize, wheat, cotton, and pea, it was found that maize and wheat have a high tolerance to TPH (Total Petroleum Hydrocarbons) contamination.