Abstract
This paper present results on soil contamination with petroleum
hydrocarbons (PHs) on soil sorptivity and hydrophobicity under different
soil moistures. The micro-infiltrometer method was used in laboratory
experiment to determine the soil water repellency index (R) and the
water drop penetration time (WDPT) test. The increase in PHs
contamination contributed to soil repellency and caused a decrease in
water sorptivity. The negative effect of contamination with PHs on soil
sorptivity depended on soil moisture and was marked especially clearly
after exceeding the critical moisture threshold. However, contamination
by PHs did not reveal significant changes when ethanol was used instead
of water. The R index and the WDPT test revealed a similar trend,
inversely related to the level of soil contamination with PHs. The total
amount of water available to plants in non-contaminated soil was
19.04%, while contamination equal to 100 g kg -1
caused a decrease to 6.36%. Hydrophobization of water-conducting pore
surfaces by petroleum hydrocarbons severely reduced infiltration and
destroyed the existing hydrological system of naturally hydrophilic
soil. The almost three-fold decrease in total amount of water has a
fundamental influence on increasing the risk of soil drought. The soil
water repellency causes a decrease in resistance to droughts and slows
the alimentation process of soil water retention. The results obtained
indicated that the interrelations presented between the level of PHs
contamination, soil sorptivity, water repellency, and soil moisture are
key to predicting the environmental effects of contamination and
effective soil remediation.