Landfills are waste disposal sites. They are often man-made depressions in the ground, or mounds above the ground, with a lining designed to prevent any leakage of waste materials, as explained by the Environmental Research Foundation. However, landfills can leak through the base, or overflow, resulting in negative impacts on the surrounding environment.
According to the U.K. Environmental Agency, about two-thirds of landfill waste is biodegradable organic matter from households, business and industry. As this material decomposes in landfill sites, it releases methane gas. Methane is a very potent greenhouse gas, up to 20 times more effective at trapping heat in the atmosphere than carbon dioxide, according to the U.S. Environmental Protection Agency. Therefore, methane emissions from landfill sites can potentially exacerbate global warming. However, according to the U.K. Environmental Agency, much of this methane gas is used to produce electricity, in turn producing carbon dioxide as a by-product, which has a weaker global warming effect. Additionally, the air surrounding landfill sites can smell unpleasant, due to the decaying organic waste.
Impact on Biodiversity
According to the Romanian Ministry of Environment and Forests, the development of a landfill site means the loss of approximately 30 to 300 species per hectare. Moreover, changes in local species assemblages, with the loss of some mammals and birds in favour of species that feed on refuse, such as rats and crows, can be expected. In addition, changes in vegetation will become apparent, regardless of the duration of the landfill site, as the ecosystem will be irreversibly changed.
As rain falls on landfill sites, the organic and inorganic constituents are dissolved, forming a highly toxic leachate, as explained by Canterbury Environmental Education Centre. This leachate collects at the base of the landfill and usually contains high levels of toxic metals, ammonia, toxic organic compounds and pathogens. Any leakage or escape of this leachate can result in serious contamination of the local groundwater. Furthermore, this mixture usually has a high biological oxygen demand, meaning it can quickly deoxygenate water. Therefore, if it were to reach rivers or lakes, it would result in a loss of aquatic life.
Effect on Soil Fertility
The mixture of toxic substances and decaying organic material can impact the soil quality of the areas surrounding a landfill site. This can compound the effects on biodiversity as local vegetation may cease to grow and/or be permanently altered.
Visual and Health Impact
Landfill sites are often very unpopular with local residents, as explained by the Canterbury Environmental Education Centre. This is due to the sites themselves ruining the natural landscape. In addition, the smell, traffic, noise and vermin that accompany landfills can lower house prices. The spread of disease, as a result of the increase in vermin surrounding landfills, is also an issue, with other adverse health effects, such as birth defects, cancer and respiratory illnesses also being linked with exposure to landfill sites.