The pollution of the soil and subsoil involves the alteration of the natural chemical composition of the soil by human activity.
Its principal causes include:
• non-biodegradable refuse
• waste waters
• plant health products
• heavy metals
• organic solvents
This type of pollution leads to the alteration of the chemico-physical and biological balance of the soil, making it prone to erosion and landslides, and may lead to harmful substances entering and climbing up the food chain.
The substances that leach down to groundwater aquifers can damage their delicate equilibrium. Interference with the latter may occur and, as a result, cause hazardous alterations to drinking water, even to that for human consumption.