Brine Spillage in the Oil Industry: The Natural Recovery of an Area Affected by a Salt Water Spill near Swan Hills, Alberta

Michael Rowell
Jean Crepin
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Salt spills are liable to become more prevalent in the oil producing regions of Alberta as the volume of brine relative to crude oil increases with the depletion of the older oil-fields.

High concentrations of sodium chloride can cause severe damage to vegetation and produce long lasting structural damage to soils.  Although current knowledge into the reclamation specifically of areas affected by
oil-field salt water is not well advanced, certain treatments are commonly employed.  These involve calcium saturation of the soil, leaching with freshwater, addition of manure and fertilizer and reseeding with salt tolerant
plant species.

The results presented in this paper suggest that with certain organic soils, extensive treatment of spill areas may not be needed.  A three year monitoring program of an area near Swan Hills, Alberta showed a gradual
reduction of salts within the original spill area and a migration of salts into the surrounding drainage areas.  The spill had occurred in a very wet area of treed Black Spruce/Sphagnum bog which was readily leached at the
surface. In 1975, soil and water samples contained up to 22,400 ppm of chloride and 34,500 ppm of sodium.  By 1977 the maximum contents of chloride and sodium recorded at the site were 4467 ppm and 2781 ppm respectively.

Extensive damage to the trees and ground vegetation was observed in 1975.  Regrowth was active throughout the area in 1977 except in one small part near the original pipeline leak.

The main drainage catchment area is a small lake to the northwest of the spill.  Concentrations of chloride in the lake have increased from 180 ppm in 1975 to 372 ppm in 1977.

If more conventional techniques used in the reclamation of saline soils had been employed additional damage to the area may have been produced.  The extreme acidity of the soil and the saturated condition of the site would
have made the establishment of non-native plant species almost impossible.

Although the treatment of most mineral soils that have been affected with brines would require a considerable reclamation effort, many organic soils may best be left to reclaim naturally.