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The presence of hydrocarbons in groundwater represents a serious risk of disease. This study tests the timing, concentration and amount of BTEX oil components during the oil vertical movement though small-scale lysimeters containing undisturbed soils of different textures and by simulating the fate of oil spills under continuous water application. Three soil types were studied: a sandy-textured, highly permeable Eutric Arenosol, AR-eu, a loamy/sandy-loamy textured Haplic Chernozem, CH-ha, and a loamy-clayey/clayey textured, swell-shrink, Luvic-Chernic Phaeozem, PH-ch-lv. Crude oil was applied as a batch application using an equivalent of 5 g oil /100 g of dry soil for a 0.02 m height in each lysimeter of the three soils studied. After oil-penetration into the soil, tap water was applied on a daily basis above the lysimeters according to infiltration rate. The breakthrough curves of the BTEX compounds show that the highest mobility in the investigated sandy AR-eu soils and loamy CH-ha soils was found for benzene followed by toluene. The other hydrocarbons only showed a limited mobility. There was no leachate from the swell-shrink PH-ch-lv soil. Soil texture and permeability thus play an important role in the movement of BTEX compounds toward the groundwater. After applying an amount of water of 200% from the total soil porosity, or an equivalent of 800-850 mm of precipitation, the leaching process did not end and there still is a leaching potential remained for these hydrocarbons. The highest amount leached per mm of effluent was also for benzene followed by toluene. There were highly significant, direct correlations between the amounts of the hydrocarbons leached and the cumulative effluent volume. The swell-shrink soils are still an effective barrier to hydrocarbons` movement toward groundwater. The BTEX aromatic hydrocarbons leached from the soils, if reach the groundwater, represent sources of pollution with severe risks for human health.

The objectives of the paper are to test if the nitrogen (mineral and organic), phosphorous and potassium fertilizers commonly used in field crops penetrate deep into the soils, and find out their leaching characteristics in the case of different-textured soils, in order to assess the potential environmental risk and recommend measures for limiting such losses. Three soil types were studied in undisturbed micro-lysimeters: sandy-textured Eutric Arenosol, AR-eu, loamy-textured Haplic Chernozem, CH-ha, and clayey-textured, swell-shrink Luvic-Chernic Phaeozem, PH-ch-lv. Two fertilizer applications containing amide N, as well as P2O5 and K2O were applied. Then distilled water was applied daily according to the infiltration rate simulating a wet season, and the effluent was collected. Soil texture and soil hydraulic properties determined the pattern of effluent concentration for all chemicals. K leaching losses from the root system zone of the soils presented the highest means, followed by N losses, while the lowest losses were found for P. Significant differences between the soils were found. Because various soil textures were studied with this experiment, the results might be used in similar environments from many countries. If global warming with extreme rain events continues, then fertilizer leaching losses could increase. To minimize nutrient leaching losses some measures are recommended. Further research should be focused on larger soil-texture diversity and cropped soils.