Possible effects of soil contamination by light non-aqueous phase liquids (LNAPLs) on soil water parameters and their consequences.

摘要

In central Germany, a loess derived site contaminated with very different light non-aqueous phase liquids (LNAPLs) emanating from production of mineral oils, was evaluated with respect to soil water retention to investigate the conditions and possibilities of deep percolation. At 4 subsites, undisturbed cores (100 cm3) were sampled from profile depths ranging between 2 and 9 m. The water retention characteristics and bulk density were determined. Results indicate that in most cases > 50% of the pore volume (PV) is occupied by water held at matrix potentials of ?15000 hPa and only approximately 10% of PV may be occupied by quickly draining water (matrix potential > -60 hPa). LNAPLs strongly decrease the surface tension gamma to values ranging from20 to 45 m.Nm-1 and increase the angle of contact alpha to 20-45?(from literature) as compared to values of 72.75 mN.m-1 and 0?for pure water. Thus, it is almost impossible to derive the correct pore size distributions of the material studied and other contaminated material from the water retention characteristics. The effect of the changed surface tension and angle of contact on the water regime (deep percolation, capillary rise) of contaminated profiles results in an enhancement of deep percolationand a restriction in capillary rise.