Micromorphological Characteristics of Polluted Soils in Tehran Petroleum Refinery

Abstract

In this study, micromorphological properties of som e samples collected from pedons polluted with petroleum refinery wastes and some ad jacent unpolluted pedons were studied. After description of the studied pedons, d isturbed and undisturbed samples were collected for physicochemical and micromorphologica l analyses. The results showed that the physicochemical properties (i.e. structure, bul k density, pH, EC and organic matter) of the soils polluted with petroleum wastes were st rongly changed. Prolonged exposure of soils to the petroleum wastes resulted in the forma tion of specific and distinctive micromorphological features. Strongly developed gra nular microstructure and infillings of solid petroleum wastes alone or mixed with soil aggregates were some of the most important pedofeatures which were observed in deepe r horizons. The existence of excrement belonging to different soil micro and mac ro fauna, coatings, hypocoatings, quasicoatings, and zones depleted from petroleum di ssolvable materials at different depths were the other features throughout the pedon s. The type of developed pedofeatures was correlated with the state of petro leum wastes and their fluidity in penetration, deposition, or dissolving and removal of soil compounds. This study demonstrated that micromorphology can be used as a powerful technique in characterization of petroleum polluted soils. Keywords: Oil contamination, Pedofeatures, Physico-chemical properties, Soil quality, Technosols.