Soil contamination

Soil contamination, soil pollution, or land pollution as a part of land degradation is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment. It is typically caused by industrial activity, agricultural chemicals or improper disposal of waste. The most common chemicals involved are petroleum hydrocarbons, polynuclear aromatic hydrocarbons (such as naphthalene and benzo(a)pyrene), solvents, pesticides, and heavy metals. The concern over soil contamination stems primarily from health risks, from direct contact with contaminated soil or consumption of plants growing in contaminated soil, vapour inhalation from the contaminants, or from secondary contamination of water supplies within (groundwater) and underlying the soil (aquifer). Mapping of contaminated soil sites and the resulting cleanups are time-consuming and expensive tasks, and require expertise in geology, hydrology, chemistry, computer modelling, and GIS in Environmental Contamination, as well as an appreciation of the history of site pollution. It has been suggested that the examination of humus forms, which necessitates only a cursory glance upon ground floor thickness and structure of the underlying mineral horizon, could used at low cost for the early detection and mapping of potential soil contamination. In North America and Europe the extent of contaminated land is best known for as many of the countries in these areas have a legal framework to identify and deal with this environmental problem. Other countries tend to be less tightly regulated despite some of them have undergone significant industrialization and are searching for more regulation.