Pollution is the introduction of harmful materials into the environment. Sometimes naturally occurring substances can be unsafe if their presence causes damage or disrupts natural cycles in the ecosystem. For example, fertilizers can benefit plants by supplying necessary nutrients, but overapplication can kill plants with the potential that drift or runoff will affect other nontargeted areas. The once-useful fertilizer now becomes a pollutant.
Land can be polluted directly through improper disposal of contaminants. The landscape theoretically functions like a target, with pollutants from the air and water also harming the environment. Air pollution sources include acid rain, which is caused by industrial emissions and particulate matter deposition from fires and combustion. Water pollution can in turn contaminate the land through agricultural and urban runoff.
The environmental impacts of land pollution depend upon the nature of the pollutant. Herbicides and fungicides degrade relatively quickly in the environment. However, nonselective pesticides can potentially harm any organism that comes in contact with it, regardless of whether it was the initial target. These poisonous agents can cause cancer and birth defects, as well as short-term skin irritations.
Industrial pollution can slow plant growth and reduce crop yield, according to a 2004 study published in the Encyclopedia of Plant and Crop Science. Some toxins persist in the environment without breaking down readily. This lack of action allows these pollutants to accumulate and become more toxic in higher concentrations.
The significance of land pollution is a function of the harm it causes. A 2007 Cornell University study estimated that pollution causes 40 percent of all deaths worldwide each year. Land pollution rarely affects only the landscape. As trash decomposes, it can release toxins into the air or into groundwater sources, compounding its effects.
Adding to the effects and significance of land pollution is the cost of cleanup. Decontamination of polluted soils, for example, requires extensive measures that can be costly. The effects of land pollution become not only environmental, but also economic. Enforcement by the U.S. Environmental Protection Agency in fiscal year 2009 resulted in 387 new environmental crime cases and commitments to clean up over 700 million pounds of hazardous waste by violators of environmental regulations. Enforcement also will bring in over $5 billion in investments for pollution cleanup.
The results of EPA enforcement illustrate the need for resources to continue to monitor compliance of land pollution issues as well as the need for education and awareness. It is essential that the general public as well as businesses become more aware of the impact of land pollution both on the environment and on people.