[Encyclios]

Soil pollution

Soil and subsoil pollution is caused mainly by the accumulation of solid and liquid waste produced by domestic and industrial activities and by the not always wise use of fertilizers and pesticides in agricultural activities. With regard to municipal solid waste, one can distinguish between rapidly decomposing putrescible organic waste, which is dangerous because it encourages the proliferation of insects and rodents, vectors of disease, and those that are not or slowly biodegradable, such as plastics, wood, paper, metal compounds, gangs, demolition materials, etc.

Industrial discharges directly into the ground can lead, if the soil is not impermeable, to the contamination of groundwater and affect its potability. The massive use of fertilizers promotes, through soil leaching, conditions of water eutrophication. Moreover, chemical fertilizers contain as impurities traces of toxic substances (arsenic, cadmium, lead, copper) that accumulate in the soil; in addition to altering the natural balance, they can pass into the edible parts of plants, which can thus become dangerous to health.

Pesticides also cause serious interference in ecosystems. These toxic substances (DDT and similar) are found concentrated in the organisms of Vertebrates and Invertebrates, after having passed through all the stages of the food chain, from plants to consumers. The case of the increasing rarefaction of birds of prey will serve as an example, in whose organism a very high concentration of pesticides taken with food and responsible for the complete sterility of these animals has been detected.