Significance

• According to American River, almost 40 percent of U.S. rivers are degraded. The primary source of the pollution affecting the aquatic resources is agricultural runoff, according to the U.S. Environmental Protection Agency (EPA). While the environmental impacts are severe, the cost in human lives is even greater. A 2007 study by Cornell University found that 40 percent of all deaths across the globe are caused by pollution.
  
  

Sources

• Human activity causes most pollution. Upward trends in atmospheric conditions such as carbon dioxide concentration coincide with the Industrial Revolution. Air pollution in the form of greenhouse gas emissions has raised the surface temperature of Earth, causing sea temperatures to rise and acidification of ocean waters to increase. In addition, acid rain has acidified soils and water resources, rendering some areas ecological dead zones, unable to support any life.
  
  

Types

• Land pollution comes in many forms, from direct contamination of the ecosystem from litter or sewage discharge to indirect types such as nonpoint source pollution. Nonpoint source pollution occurs when precipitation over the land causes runoff from urban settings or farmlands to wash into surface water sources such as lakes and ponds. Land cover and topography play a role in determining the extent of the environmental contamination.
  
  

Long-Term Effects

• Land pollution is especially insidious when it carries long-term impacts. Some contaminants such as mercury and lead persist in the environment and do not degrade over time. Rather, their negative effects increase as concentrations of toxins rise, if left unchecked. Ironically, in some cases human activity is necessary to mitigate the effects of land pollution caused by people.
  
  

Prevention/Solution

• The first step toward alleviating land pollution is awareness. For example, regulations imposed by states and the EPA brought upon over a 70 reduction of sulfur dioxide emissions from 1980 to 2008, lessening the impacts of acid rain on the land. Indeed, the message is being heard. A 2009 Harris Interactive poll found that more than 80 percent of Americans take actions to reduce their carbon footprint by such activities as installing energy-efficient light bulbs or buying a more fuel-efficient vehicle.