Evaluation of contaminated urban soils
Introduction
Soil pollution is a degradation of soil quality associated with the presence of chemical substances.[1] It is defined as the increase in the concentration of chemical compounds, which causes harmful changes and reduces their potential use, both by human activity and by nature.[2][3].
Soil contamination is when solid, liquid or gaseous substances or elements are introduced that affect soil biota, plants, animal life and human health.
Soil can become contaminated in various ways: when underground storage tanks break, when pesticides are applied, by leaks from the sanitation network and blind wells, or by direct accumulation of industrial or radioactive products.
The most common chemicals are petroleum derivatives, solvents, pesticides and other heavy metals. This phenomenon is closely related to the degree of industrialization and intensity of the use of chemical products. Among the most significant soil contaminants are hydrocarbons such as petroleum and its derivatives, heavy metals common in batteries, Methyl tert-butyl ether (MTBE),[4] herbicides and pesticides generally sprayed on industrial crops and monocultures, and organochlorines produced by industry. Also the landfills and ecological belts that bury large amounts of garbage from cities. This contamination can affect health directly and by coming into contact with drinking water sources.
Regarding soil contamination, the risk is primarily to health, directly and when coming into contact with sources of drinking water. Delineating contaminated areas and resulting cleanup are time-consuming and costly tasks that require extensive geology, hydrography, chemistry, and computer modeling skills.
The main causes of soil pollution are: plastics dumped without control, uncontrolled discharges of organic matter from wastewater treatment plants or agricultural activities, application of pesticides (insecticides, herbicides, fungicides) without following safety instructions or radioactive substances from nuclear tests or industrial facilities that contaminate natural or artificial soil.[3] Soil pollution has been established as an important alteration that is directly reflected on the earth's surface, starting of different causes that are estimated to worsen over time if appropriate measures are not taken on the planet.
The main anthropogenic sources of soil pollution are chemicals, industrial activities, domestic, livestock and municipal waste, agrochemicals and petroleum products. These chemicals are released into the environment accidentally, for example, through oil spills or leaks from landfills, or intentionally, as occurs with the use of fertilizers and pesticides, irrigation with untreated wastewater, or application of sewage sludge to the soil.[5].