What is Contaminated Land?

Land that is contaminated contains substances in or under the land that are actually or potentially hazardous to health or the environment. Britain has a long history of industrial production and throughout the UK there are numerous sites where land has become contaminated by human activities such as mining, industry, chemical and oil spills and waste disposal. Contamination can also occur naturally as result of the geology of the area, or through agricultural use.

What are the risks?The presence of contamination in the ground does not necessarily mean that there is a problem. In many cases there will be minimal risk from living or working on contaminated ground. Indeed many contaminated sites have been successfully and safely redeveloped to provide high quality housing and working environments.

In a few cases some sites are so contaminated that they present an unacceptable risk to human health or the environment. Human exposure to contaminants can be through inhalation of dust or gases, contact with soil, or through food grown on the land. Leachates (pollutants draining from the site in liquid form) can pollute groundwater and rivers or ponds. Some contaminants may be corrosive, and some can pose a risk of explosive fire.

The effects on human health and on the environment will depend on the type and amount of contaminant involved.

How long does contamination last?This is very specific to the contaminant and the local circumstances of the site.

Once a contaminant reached the soil it may break down or be neutralised; be washed out by rain; evaporate or remain in the soil building up to high concentrations. What happens will depend on the balance between the rate of input and the rate of removal of the contaminant, the properties of the contaminant and the soil, the rate of rainfall and the activity if the soil organisms. When contaminants build up, it may not be permanent. However, soil can sometimes remain polluted indefinitely.

Brownfield development and contaminated land

There are areas in towns and cities that have fallen into disuse. Some have been left as unsightly wasteland or derelict buildings are known as "Brownfield" land. These sites can have a detrimental effect on the environment and social quality of the area and it is therefore beneficial to redevelop these sites.

Much of this Brownfield land is contaminated and in past years has often been considered unattractive to clean up and bring back into beneficial use, especially where there have been alternative “Greenfield” sites available. However, modern technologies and approaches have enabled this kind of land to be brought back into beneficial uses.

The Government now wants to bring as much Brownfield land as possible back into use and is encouraging the regeneration of previously developed land to limit unnecessary development of Greenfield sites and preserve the countryside. Strict targets have been set to encourage building of the majority of new houses on brownfield land.

Cleaning up contaminated land.Until recently, contamination usually became an issue only where there was a pollution incident, or where the site was selected for redevelopment through the planning process. Now, under the requirements of Part 2A of the Environmental Protection Act (EPA) 1990, local authorities are required to make assessments of land in their areas to decide which sites are or could be causing harm or pollution and to take action to ensure that it is made safe. This might result in the original polluters, landowners, and other responsible persons (including domestic property owners) becoming responsible for cleaning up a site.

If land is found to be contaminated, it must be restored to a state in which is it “suitable for use”. The local authority will agree with the responsible persons the degree to which the land should be cleaned up, in relation to the risk that the land is posing to health or the environment and pollution of watercourses and groundwater.

In the case of redevelopment, the developer will be responsible for ensuring that the site is suitable for its intended use, and in most cases the enforcement of any remediation requirements will be made via formal agreements such as planning conditions and building control.

What solutions are available?A site affected by contamination may need remedial treatment before it can be used redeveloped, and “Remediation Notices” can be issued under EPA to ensure treatment of land in existing use. There are many ways in which this may be achieved, ranging from “dig and dump” (taking contaminated soils away to licensed landfill sites) to the use of techniques that treat soil and water either in-situ or at the site of origin to remove, destroy or reduce the amount or potency of the contamination. The choice of approach is very site specific and depends on various factors such as the type of contamination, the physical circumstances of the site, ongoing site use and the regulatory requirements.

(http://www.environmental-protection.org.uk/land-quality/contaminated-land)

Reducing Acid Rain

There are several ways to reduce acid rain − more properly called acid deposition − ranging from societal changes to individual action. It is critical that acid deposition be reduced, not only in the United States and Canada, but also throughout the world to preserve the integrity of natural habitats, as well as to reduce damage to man-made structures.

EPA has taken steps to limit the amount of NOx and SO2 emitted into the atmosphere because they are the main contributors to acid deposition.

Additionally, individuals and society as a whole can participate in various efforts to help reduce acid deposition:

Understand acid deposition’s causes and effects

Clean up smokestacks and exhaust pipes

Use alternative energy sources

Restore a damaged environment

Look to the future

Take action as individuals

Understand acid deposition’s causes and effects

To understand acid deposition’s causes and effects, and to track changes in the environment, scientists from EPA, state governments, and academia study acidification processes. They collect air and water samples and measure them for various characteristics such as pH and chemical composition, and research the effects of acid deposition on human-made materials such as marble and bronze. Finally, scientists work to understand the effects of sulfur dioxide (SO2) and nitrogen oxides (NOx) − the pollutants that cause acid deposition and contribute to particulate matter − on human health.

To solve the acid rain problem, people need to understand how acid rain damages the environment. They also need to understand what changes could be made to the air pollution sources that cause the problem. The answers to these questions help leaders make better decisions about how to control air pollution and therefore, how to reduce − or even eliminate − acid rain. Because there are many solutions to the acid rain problem, leaders have a choice of which options or combination of options are best.

Clean up smokestacks and exhaust pipes.Almost all of the electricity that powers modern life comes from burning fossil fuels such as coal, natural gas, and oil. Acid deposition is caused by two pollutants that are released into the atmosphere when fossil fuels are burned: sulfur dioxide (SO2) and nitrogen oxides (NOx). Coal accounts for most U.S. SO2 emissions and a large portion of NOx emissions. Sulfur is present in coal as an impurity, and it reacts with air when the coal is burned to form SO2. In contrast, NOx is formed when any fossil fuel is burned.

There are several options for reducing SO2 emissions, including using coal containing less sulfur, washing the coal, and using devices called “scrubbers” to chemically remove the SO2 from the gases leaving the smokestack. Power plants can also switch fuels − for example, burning natural gas creates much less SO2 than burning coal. Certain approaches will also have the additional benefit of reducing other pollutants such as mercury and carbon dioxide (CO2). Understanding these “co-benefits” has become important in seeking cost-effective air pollution reduction strategies. Finally, power plants can use technologies that do not burn fossil fuels. Each of these options, however, has its own costs and benefits; there is no single universal solution.

Similar to scrubbers on power plants, catalytic converters reduce NOx emissions from cars. These devices have been required for over 20 years in the United States, and it is important to keep them working properly. Recently, tailpipe restrictions were tightened to help curb NOx emissions. EPA also continues to make, changes to gasoline that allow it to burn cleaner.

Use alternative energy sources.There are other sources of electricity besides fossil fuels. They include nuclear power, hydropower, wind energy, geothermal energy, and solar energy. Nuclear and hydropower are used most widely in the United States, while wind, solar, and geothermal energy have not yet been harnessed on a large enough scale to make them economically-feasible alternatives.

There are also alternative energies, such as natural gas, batteries, and fuel cells, available to power automobiles.

All sources of energy have environmental costs as well as benefits. Some types of energy are more expensive to produce than others, which means that not all Americans can afford all of them. Nuclear power, hydropower, and coal are the cheapest forms of energy today, but advancements in technologies and regulatory developments may change this in the future. All of these factors must be weighed when deciding which energy source to use today and which to invest in for tomorrow.

Restore a damaged environment.Acid deposition penetrates deeply into the fabric of an ecosystem, changing the chemistry of the soil and streams and narrowing − sometimes to nothing − the space where certain plants and animals can survive. Because there are so many changes, it takes many years for ecosystems to recover from acid deposition, even after emissions are reduced and the rain pH is restored to normal. For example, while visibility might improve within days, and small or episodic chemical changes in streams improve within months, chronically acidified lakes, streams, forests, and soils can take years to decades, or even centuries (in the case of soils) to heal.

However, there are some things that people can do to bring back lakes and streams more quickly. Limestone or lime (a naturally occurring basic compound) can be added to acidic lakes to “cancel out” the acidity. This process, called liming, has been used extensively in Norway and Sweden but is not used very often in the United States Liming tends to be expensive, has to be done repeatedly to keep the water from returning to its acidic condition, and is considered a short-term remedy in only specific areas, rather than an effort to reduce or prevent pollution. Furthermore, it does not solve the broader problems of changes in soil chemistry and forest health in the watershed, and it does nothing to address visibility reductions, materials damage, and risk to human health. However, liming does often permit fish to remain in a lake, allowing the native population to survive in place until emissions reductions reduce the amount of acid deposition in the area.

Look to the future.As emissions from the largest known sources of acid deposition − power plants and automobiles − are reduced, EPA scientists and their colleagues must assess the reductions to make sure they are achieving the results that Congress anticipated when it created the Acid Rain Program in 1990. If these assessments show that acid deposition is still harming the environment, Congress may begin to consider additional ways to reduce emissions that cause acid deposition. It may consider additional emission reductions from sources that have already been controlled, or methods to reduce emissions from other sources. Congress may also focus on energy efficiency and alternative energy. Implementation of cost-effective mechanisms to reduce emissions and their impact on the environment will continue to evolve.

Take action as individuals.It may seem like there is not much that one individual can do to stop acid deposition. However, like many environmental problems, acid deposition is caused by the cumulative actions of millions of individual people. Therefore, each individual can also reduce their contribution to the problem and become part of the solution. Individuals can contribute directly by conserving energy, since energy production causes the largest portion of the acid deposition problem. For example, you can:

Turn off lights, computers, and other appliances when you're not using them.

Use energy-efficient appliances: lighting, air conditioners, heaters, refrigerators, washing machines, etc. For more information, see EPA’s ENERGY STAR Program.

Only use electric appliances when you need them.

Keep your thermostat at 68°F in the winter and 72°F in the summer. You can turn it even lower in the winter and higher in the summer when you are away from home.

Insulate your home as best you can.

Carpool, use public transportation, or better yet, walk or bicycle whenever possible

Buy vehicles with low NOx emissions, and properly maintain your vehicle.

Be well informed.

(http://www.epa.gov/acidrain/reducing/index.html)

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