Importance of soil-water relations in assessing the endpoint of bioremediated soils. II. Water-repellency in hydrocarbon contaminated soils.

摘要

Water movement was studied in a hydrocarbon-contaminated soil, the same soil after 3 years of bioremediation, and a control soil from the same site. There was a critical soil water content around 18% (bioremediated soil) and 20% (contaminated soil),above which the sorptivity of the contaminated soil was near that of the control soil. For soils with water contents below this value, there was a strong divergence in sorptivity between contaminated and control or bioremediated soils. These results suggest that water availability in contaminated soils will be highly dependent on soil water properties as water potential approaches the permanent wilting point (-1.5 MPa matrix potential). Infiltration of water into air dry (2% moisture content, w/w) hydrocarbon-contaminated soils was up to three orders of magnitude slower than for the control soil. For air-dried soils, the infiltration rate of the contaminated and bioremediated soils was constant over time. This was in contrast to the control soil whereinfiltration rate was a function of the reciprocal of the square root of time.