Ninth International Conference on Permafrost ... - IARC Research

The Oil Pollution Influence of Frozen Soils on Their Geophysical CharacteristicsYu.D. ZykovThe Moscow State University, Geological Faculty, Geocryology DepartmentA.V. KoshurnikovThe Moscow State University, Geological Faculty, Geocryology DepartmentI.V. AnisimovaThe Moscow State University, Geological Faculty, Geocryology DepartmentT.E. MironovaThe Moscow State University, Geological Faculty, Geocryology DepartmentHigh rates of oil-extracting development and processindustries in the cryolitozone have created a sharpgeoenvironmental problem. It is pollution of naturaltechnicalsystems by oil and its products. The general lossesof oil are estimated within the limits of 2–10% from annualextraction or from 5 to 25 million tons a year (Arens 1994,Masur 1995), in western Siberia approximately 0.7 and 0.4million tons in the Timano-Pechora region (Permafrost …2002).In the Geocryology Department at Moscow StateUniversity, a special program on studying moving pollutingorganic substances (Ershov et al. 1996, Chuvilin et al. 2001)has been carried out. It is found that oil migrates in frozensoil and is present even at negative temperatures (up to -20°Cand below). The research is confirmed recently in laboratory(Chuvilin et al. 2001) and field (Biggar et al. 1998).Hydro carbonic pollution leads to change in thetemperature-humid mode of soil thawing due to change inheat conductivity and thermal capacity—properties of frozendisperse soils as the bases of engineering constructions. Itcan also lead to development of negative geocryologicalprocesses and phenomena (Korolev 2001).Thus, detection of and supervision over the dynamics ofthe pollution process became one of the serious ecologicalproblems. Geophysical methods can be an important toolif the change in frozen soil properties laws is known. Forthese purposes laboratory research is executed at some set ofvalues of a pollution degree (Z), from 0 to 10% (to weight ofa mineral part) (Zykov et al. 2003).Specific electric resistance (ρ) and polarizability (η) wereУЭС, Омм100000100001000100101measured by peak-phase method on “Spectrum” equipment(Open Company, Moscow State University–Geophysics)with the installation of four-electrodes. Speeds of longitudinalwaves (Vp) were measured by ultrasonic equipment UD4-130 (Scientific Industrial Union “LUCH”) on frequencies 60and 100 kHz.The executed measurements have shown that, in mostcases, pollution causes a decrease in ρ (УЭС) [u.e.r.] andV p. Thus, apparently from the resulting figures, in soils notsalted, at negative temperatures, the influence of pollutionis shown more strongly (Fig. 1). Except for what is wellУЭС, Омм10000010000100010010-40 -20 0 20 t, 40о С1 2 3 4 5Figure 1. Temperature dependences УЭС [u.e.r.] (ρ) in oil and innot salted polluted sand; a degree of pollution (Z) and humidity(W). 1 – Z = 0, W = 20%; 2 – Z = 0, W = 10%; 3 – Z = 2.5%, W =10%; 4 – Z = 10%, W = 0; 5 – oil.V p, м/с40003000200010000 ,1-40 -20 0 20 t, о 40 С0-40 -20 0 20 t, 40о С1 2 2' 3 3'Figure 2. Temperature dependences. A: УЭС [u.e.r.], and B: V in the sand salted by solution NaCl of various concentration (С) with variousPdegree of pollution (Z) at the fixed humidity (W = 10%). 1 – C = 0.0476; 2 – Z = 0; 2 – C = 0.0476; Z = 2.5%; 2 ′ – C = 0.0476; Z = 5%; 3 – C= 0.0909; Z = 2.5%; 3 ′ – C = 0.0909; Z = 5%.367