EFECTOS DE LAS AGUAS RESIDUALES DE POZOS PETROLEROS SOBRE LOS SUELOS DE SABANAS UBICADAS CERCA DE EL FURRIAL, ESTADO MONAGAS, VENEZUELA

Abstract

In terrestrial environments affected by oil operations, oil drilling and sewage fluids (SF) represent an environmental and aesthetic problem of importance. Before watered to the environment, SF rich in suspended solids and with potential contaminants, are transported to a tank treated with a flocculant agent and corrected for pH. The resulting waters are then disposed to the local savannas. It is important to know the effects that those treated SF may have on the surrounding ecosystems. This contribution aims to analyze the levels of soluble salts and heavy metals in the soils adjacent to oil wells located in the eastern part of the Venezuelan savannas after irrigation with treated SF. The treated SF watered to the environment have a liming effect on the natural acidity of soils. In general, no high levels of heavy metals (Fe, Mn, Cu and Zn) were found nor soluble aluminum in treated soils, which is due to the rise in pH after treatment. The soils treated with effluents generally had a higher sodium concentration. However, there is no potential environmental risk in the amounts of soluble sodium released to the sandy ultisols since the good internal drainage of these and the proper precipitation of the area allow the soon eviction of salts without danger of salinization. Nevertheless, strict monitoring is recommended, in particular of the pH levels of wastewater before being irrigated to the surrounding savannas.