Soil contamination or soil pollution as a part of land degradation is caused by the presence of xenobiotics (human-made) chemicals or other alteration within the natural soil environment. it's typically caused by industrial activity, agricultural chemicals or improper disposal of waste. the foremost common chemicals involved are petroleum hydrocarbons, polynuclear aromatic hydrocarbons (such as naphthalene and benzo(a)pyrene), solvents, pesticides, lead, and other heavy metals. Contamination is correlated with the degree of industrialization and intensity of chemical substance. the priority over soil contamination stems primarily from health risks, from direct contact with the contaminated soil, vapours from the contaminants, or from secondary contamination of water supplies within and underlying the soil. Mapping of contaminated soil sites and also the resulting cleanups are time-consuming and expensive tasks, requiring extensive amounts of geology, hydrology, chemistry, computer modeling skills, and GIS in Environmental Contamination, further as an appreciation of the history of business chemistry. In North America and Western Europe the extent of contaminated land is best known, with many of nations in these areas having a legal framework to spot and pander to this environmental problem. Developing countries tend to be less tightly regulated despite a number of them having undergone significant industrialization..