What is soil contamination?
Soil contamination refers to soil contamination with abnormal concentrations of toxic substances. It is a serious environmental concern as it is home to many health hazards. For example, exposure to soils that contain high concentrations of benzene increases your risk of leukemia. It is important to understand that all soils contain compounds that are harmful/toxic to humans and other living organisms. However, the concentration of such substances in uncontaminated soils is low enough that they pose no threat to the surrounding ecosystem. When the concentration of one or more of these toxic substances is high enough to cause damage to living organisms, the soil is said to be contaminated. The main cause of soil contamination is usually one of the following: Agriculture (excessive/inappropriate use of pesticides) Excessive industrial activity Mismanagement or ineffective disposal of waste The challenges faced in soil remediation (soil decontamination) are closely related to the extent of soil contamination. The higher the contamination, the greater the need for remediation resources. CAUSES AND TYPES OF SOIL CONTAMINATION Phenomena such as erosion, organic carbon loss, increased salt content, compaction, acidification and chemical contamination are the main causes of current soil degradation. In addition, FAO distinguishes between two types of soil contamination: Specific pollution: explained by particular causes, which occurs in small areas whose reasons can be easily identified. Land pollution like this is usually found in cities, former factories, around roads, illegal landfills and wastewater treatment stations. Widespread pollution: covers large areas and has several causes whose reasons are difficult to identify. Cases like these involve the spread of pollutants by air-underground-water systems and seriously affect human health and the environment. Among the most common causes of soil pollution caused by human activity, FAO highlights industry, mining, military activities, waste - including technological waste - and wastewater management, agriculture, livestock and the construction of urban and transport infrastructures. What are the negative consequences of soil contamination? Soil pollution has a wide spectrum of negative consequences affecting plants, animals, humans and the ecosystem as a whole. Because children are more susceptible to disease, contaminated soil poses a greater threat to them. This subsection details some important effects of soil contamination. Effects on humans Soil contaminants can exist in all three phases (solid, liquid and gaseous). Therefore, these contaminants can enter the human body through various channels, such as direct skin contact or inhalation of dust from contaminated soil. Short-term effects of human exposure to contaminated soil include:
Exposure to high levels of lead can result in permanent damage to the nervous system. Children are particularly vulnerable to lead. CNS (central nervous system) depression. Damage to vital organs such as the kidney and liver. Increased risk of developing cancer. It should be noted that many soil pollutants, such as oil hydrocarbons and industrial solvents, have been linked to congenital disorders in humans. Soil contamination can therefore have several negative effects on human health. Effects on plants and animals Since soil contamination is often accompanied by a decrease in nutrient availability, plant life ceases to thrive in these soils. Soils contaminated with inorganic aluminum can be toxic to plants. In addition, this type of contamination often increases soil salinity, making it inhospited for the growth of plant life. Plants that grow in contaminated soils can accumulate high concentrations of soil contaminants through a process known as bioaccumulation. When these plants are consumed by herbivores, all accumulated contaminants pass through the food chain. This can result in the loss/extinction of many desirable animal species. In addition, these pollutants can reach the top of the food chain and manifest as diseases in humans. How can soil contamination be controlled? Several technologies have been developed to address soil remediation. The following are some important strategies followed for the decontamination of contaminated soils. Excavation and subsequent transport of contaminated soils to remote and uninhabited locations. Removing contaminants by thermal remediation: the temperature rises to force contaminants to pass into the steam phase, after which they can be collected by steam extraction. Bioremediation or phytoremediation involves the use of microorganisms and plants for soil decontamination. Mycoremediation involves the use of fungi for the accumulation of heavy metal contaminants.
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Air pollution has become the biggest environmental cause of premature death, overtaking poor sanitation and a lack of clean drinking water. According to the WHO, more than 3.5 million people are being killed each year by the air that they breathe in urban areas, and the number is rising. Air pollution now kills twice as many people as HIV/AIDS. That’s the stark message from the latest OECD report, The Cost of Air Pollution: Health Impacts of Road Transport.
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