engleski

Monitoring Forest Ecosystem Soils in the Oilfield Area of Central Croatia

Investigations of forest soil contamination with oil and/or drilling fluids in the oilfield of Žutica in Central Croatia were conducted in six localities selected in the spring of 2003. Five sample plots sized 25 x 25 m were established in the localities affected with diverse types of soil pollution, regardless of whether it was mud ditch or a point of pipe burst in the pipe system within the field itself. One sample plot was designated as a control plot. Sampling is done twice a year at three soil depths. After sampling and general soil characterisation, the content of total and mineral oils (oil hydrocarbons) in the soil and in water eluate, electrical conductivity and heavy metal content were measured in composite samples. The content of total and mineral oil is still periodically determined in the same points of the plots. Past results indicate that the soil is not loaded with heavy metals and salts ; however, the results differ with regard to total and mineral oils. In view of the fact that plots 1-5 were established in the locations of detected pollution of soil with drilling fluids, it is evident that these influences differ significantly. They may involve climatic effects (hydrocarbon biodegradation), liquid gas quantity or distribution in the area, leading to varying degrees of changed concentrations (due to microrelief, soil humidity or surface water). According to preliminary research results, increased oil hydrocarbons content is found in the entire soil profile in the area of the restored mud ditch. The highest hydrocarbon load is present in the part of the micro-depression affected by an oil slick. In other localities, preliminary measurements do not indicate loading of soil with hydrocarbons.

soil contamination; soil monitoring; oilfield

nije evidentirano