Earth Science: Environmental Protection – Soil Pollution and Erosion
The availability of productive land suitable for cultivation is extremely important to ensure sufficient food supply. Such land is becoming scarce due to soil contamination and deforestation which cause soil erosion.
Today’s food production is increased by intensive agriculture and animal husbandry, as well as the targeted use of fertilizers and pesticides. This may not only pollute both the groundwater and surface water, especially when used in monocultures, but may also reduce the content of organic compounds, as well as the number of organisms living in the soil.
As a result the natural fertility of the soil is reduced. Areas that have already been cultivated are often lost forever due to overuse, waterlogging, salinization, and desertification.
Tropical rain forests are often sites that are cleared for agricultural purposes. More often than not, cultivating such land turns out to be problematic because many of these areas are hardly suitable for intense agricultural activities. Long-term use is usually only possible by selecting adapted seeds, fertilizers, and artificial irrigation. The latter may result in entire lakes drying out.
An example of this happening is the Aral Sea, which has completely dried out. The clear-cutting of rain forests for wood or cultivation leads to large-scale soil erosion. Valuable land is increasingly lost to housing developments, road construction, and the development of recreational areas. These developments seal the soil, lowering the groundwater level, change the microclimate adversely, and deprive plants and animals of their habitat.
The flood risk increases due to the lack of rainwater drainage pathways into the soil. Large quantities of waste are produced in the industrialized countries every year and often disposed of in unsafe locations. This waste includes toxic and sometimes even radioactive waste.
If landfill sites are insufficiently reinforced, toxic agents may seep into the lower layers of the ground and, in the worst case, contaminate the groundwater. Appropriate and safe disposal of toxic industrial waste products is very costly. Therefore this type of waste is often “exported” to developing countries where it may not be disposed of in an ecologically safe manner.
CATASTROPHIC FLOODING IN BANGLADESH
Due to the coinciding humid monsoons of the summer season and the melting snow from the Himalaya, Bangladesh frequently suffers from flooding. Clear-cutting in large forested areas results in soil erosion.
The Ganges and the Brahmaputra have to carry an increasing amount of sludge, which causes these rivers to overflow. Tropical cyclones followed by extremely high storm surges intensify the flooding that often re-suits in a catastrophe.