Ch 5 Human Impact on an Ecosystem 1 Pollution

Need to know Define the term: Pollution. State areas affected by pollution. State mechanisms to control pollution. Explain the difference between the terms pollutant and pollution. Discuss the ecological impact of one human activity.

Human Impact on Ecosystems We are going to look at 3 ways that humans affect ecosystems: Pollution Conservation Waste Management

Pollution Pollution is the addition of harmful substances to the environment. It is the most harmful human impact and affects air, fresh water, sea, soil and land. Pollution is any human addition (contamination) to a habitat or the environment that leaves it less able to sustain life. Pollutants are substances / Chemicals of human origin that harm the environment.

Some Types of Pollution Domestic Pollution Industrial/Air Pollution River/Water Pollution Agricultural Pollution – slurry, if it gets into a river/pond

Pollutants are substances that cause harm to the environment. CO2 from burning fossil fuels SO2 from factory chimney are produced by human activities

Pollutants Some pollutants are normally present in an environment, e.g. CO2 but levels are increased by human activity. Other pollutants never exist in an environment e.g. oil slick, CFCs

Learning Check 1 Explain the term Pollution. Name some Types of Pollution. Explain the term Pollutant.

Effect of one pollutant from one area - Agricultural, Industrial or Domestic Source Effects Agricultural Slurry & Fertiliser Washed or leached from land Formation of algal blooms and eutrophication Industrial Sulphur dioxide Burning fossil fuels Forms ‘acid rain’ Domestic Plastic bags Shopping Non-biodegradable Suffocate small animals, Litter

Eutrophication & Algal bloom Eutrophication: a condition where lakes become over-enriched with nutrients, resulting from excess artificial fertilisers washed into rivers and lakes. There is a rapid increase in the growth of alga - algal bloom as they use up the nutrients.

Eutrophication & Algal bloom When all the nutrients are used up the algae die and are broken down by bacteria, which use up the oxygen in the water resulting in the death of aquatic organisms such as fish.

Eutrophication animation Water Pollution Water pollution - Kate Bush

Control of Pollutants in the selected area - Agricultural, Industrial or Domestic Control Measures Agricultural Slurry & Fertiliser Avoid spreading these: on wet, waterlogged, frozen or steeply sloping land within 1.5m of any watercourse. Industrial Sulphur dioxide Fit catalytic scrubbers in factory chimneys Domestic Plastic bags Bag tax/levy. Reuse/Recycle bags

Learning Check 2 Explain the term Eutrophication. Explain the term Algal bloom. Give an example of a method used to Control Agricultural Pollutants. Give an example of a method used to Control Industrial Pollutants. Give an example of a method used to Control Domestic Pollutants.

Ecological impact of one human activity – Industrial Pollution Burning Fossil Fuels Air pollution caused by human activities, including industrial and energy production, the burning of fossil fuels and increased use of certain types of transport, causes serious health problems for hundreds of thousands of Europeans every year. A 2004 World Health Organization evaluation found that air pollution contributed to 100,000 premature deaths and the loss of 725,000 working days annually in Europe.

Acid rain Burning of fossil fuels releases acidic oxides into the air - Sulphur dioxide (SO2) and nitrogen oxides. SO2 dissolves in rainwater to form sulphuric acid (H2SO4) The resulting rain is very acidic – pH 4.0, normal rain water - pH 5.5. Acid deposition,/ acid rain as it is commonly known, occurs when emissions of sulfur dioxide (SO2) and oxides of nitrogen (NOx) react in the atmosphere with water, oxygen, and oxidants to form various acidic compounds. These compounds then fall to the earth in either dry form (such as gas and particles) or wet form (such as rain, snow, and fog).

Video on Coal-Combustion-and-Acid-Rain Air pollution Facts

From 1997 to 2006 the EU-27 recorded a 28 % decline in weighted emissions of acidification gases.

While government policies aimed at reducing  acid rain have largely been effective, acid rain still continues to affect ecological systems and is  likely contributing to forest degradation, fish kills, and tainted water quality. During the early 1980s and 90s, dramatic visions of acid precipitation corroding buildings and killing trees captured the minds of the public.

Effects of Acid Rain Causes soil to become more acidic. The lower pH causes minerals e.g. Al, K, Ca and Mg, required for normal plant growth to be washed (leached) from the soil into lakes and water supplies. Soil becomes impoverished and fish die in highly mineralised water. Inhibits chlorophyll formation. Burns the leaves of plants.

6. Erodes limestone buildings 7. Causes breathing difficulties – irritates the delicate lining of the lungs

Effects of acid rain & global warning

6. Erodes limestone buildings 7. Causes breathing difficulties – irritates the delicate lining of the lungs

Dealing with acid rain Reducing the quantity of fossil fuels burned. Using catalysts to treat chimney gases (scrubbers are fitted to the insides of chimneys). Catalytic converters fitted to modern cars. Developing alternative ‘clean’ energy sources. A catalytic converter (colloquially, "cat" or "catcon") is a device used to reduce the array of emissions from an internal combustion engine. A catalytic converter works by using a catalyst to stimulate a chemical reaction in which the by-products of combustion are converted to produce less harmful and/or inert substances, such as the very poisonous carbon monoxide to carbon dioxide. In automobiles, this typically results in 90% conversion of carbon monoxide, hydrocarbons, and nitrogen oxides into less harmful gases. Most of the world now has emissions regulations which cars with petrol (gasoline) and other spark-ignition engines can only meet with catalytic converters.

Learning Check 3 What is acid rain? How is acid rain formed? List some of the effects of acid rain. How can the probloms dealing with acid rain be controlled?

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