Aquatic & Terrestrial Environmental Impacts
Aquatic Environmental Impacts
Water Pollution
Changes in water characteristics caused by human activities have a significant impact on the hydrosphere. Pollution stems from the overexploitation of aquatic ecosystems and water resources.
Contamination of Aquatic Environments
According to the WHO, water is considered contaminated when it loses its suitability for its intended use. This contamination manifests as changes in temperature, color, and density, rendering the water harmful to humans.
Contaminants of Aquatic Environments
Foreign substances introduced into water bodies can be categorized as follows:
- Organisms and substances that harm living things: These include bacteria, viruses, and parasitic worms, which can spread diseases. Chemical contaminants such as PVC, DDT, and radioactive waste also fall under this category.
- Substances that decrease oxygen content in the water: Increased temperature and decomposing organic matter contribute to oxygen depletion.
- Substances that impair the natural values of water: Turbidity hinders the passage of light, affecting photosynthesis and altering water properties.
Effects of Aquatic Pollution
Rivers and Lakes
Rivers: Rivers naturally carry salts and other solids, contributing to natural pollution. However, human activities introduce waste that rivers cannot effectively eliminate. The retrieval mechanism of water depends on its mobility and capacity for renewal, but this mechanism fails when excessive substances are present. Consequently, the water may look and smell unpleasant, making it difficult to reuse for various purposes.
Lakes: Lakes are static water bodies with limited clearance capacity, making them more susceptible to pollution than rivers. Eutrophication, an increase in the mass of water, particularly nitrates, leads to excessive algae and plant growth. This, in turn, increases oxygen consumption, harming aquatic life. To mitigate this, it’s crucial to avoid domestic and agricultural waste, purify water, and reduce phosphorus in detergents. Thermal pollution from industries can also raise water temperatures, disrupting reproductive cycles in lakes and rivers.
Contamination of Groundwater
Aquifers are easily altered, and excessive extraction from wells can lead to depletion. Alterations in watercourses can even cause rivers to dry up. Groundwater contamination can result from excessive fertilizer and pesticide use, over-extraction, septic tanks, cesspools, ranching, and industrial activities. Unlike rivers, groundwater cannot be easily purified. It takes hundreds of years for natural debugging to occur, and artificial debugging is both difficult and expensive.
Pollution of the Seas and Oceans
Seas and oceans are the ultimate recipients of all river and groundwater flows, making them vulnerable to contamination. Despite their vast volume and natural treatment capacity, the increasing influx of pollutants poses a significant threat. Oil spills, depending on the type of oil (crude or refined), quantity, and proximity to the coast, can have devastating consequences. Marine animals can die from oil impregnation, and fishing activities near the shore can be severely affected. Oil slick removal can be achieved through natural processes (albeit slow) or artificial removal processes. Bioremediation, involving the introduction of microorganisms capable of degrading petroleum, is considered the most effective method.
Indices of Water Quality
Water quality is assessed based on various parameters. Physical parameters like turbulence and clarity depend on microorganisms. Two commonly used chemical parameters are dissolved oxygen and biological oxygen demand (BOD). The chemical oxygen demand (COD) and pH are also important indicators. Biological parameters assess the number of microorganisms, including viruses, bacteria, fungi, and algae, present in the water.
Terrestrial Environmental Impacts
Soil Contamination
From an economic perspective, waste encompasses all discarded materials generated by consumption activities. From an ecological standpoint, waste includes all forms of energy or material discharged into the environment. There are five main types of waste:
- Municipal solid waste: Generated in urban areas, this heterogeneous mix comprises household and commercial waste.
- Medical waste: Generated in hospitals and pharmaceutical facilities.
- Agriculture and forest residues: This includes agricultural and livestock excrement. Pesticides, widely used in agriculture, are a major cause of soil pollution.
- Industrial waste: Often containing toxic and hazardous substances like arsenic and cadmium.
- Radioactive waste: Containing radioisotopes with varying half-lives (short-lived, less than 30 years, or long-lived, more than 30 years). The intensity of their activity can be low or medium (research or medical waste) or high (power plants).
Deforestation and Desertification
The disappearance of forests has different implications depending on the type of forest. In temperate forests, the abundance of organic matter in the soil helps retain fertility, making restoration possible. However, in tropical forests with limited soil organic matter, deforestation is more detrimental as vegetation struggles to regenerate. The consequences of deforestation include soil erosion, changes in the water cycle, reduced photosynthetic processes, loss of biodiversity, and desertification.