Nuclear and Chemical Accidents

1952

Dec. 12, Chalk River, nr. Ottawa, Canada: a partial meltdown of the reactor's uranium fuel core resulted after the accidental removal of four control rods. Although millions of gallons of radioactive water accumulated inside the reactor, there were no injuries.

1953

Love Canal, nr. Niagara Falls, N.Y.: was destroyed by waste from chemical plants. By the 1990s, the town had been cleaned up enough for families to begin moving back to the area.

1957

Oct. 7, Windscale Pile No. 1, north of Liverpool, England: fire in a graphite-cooled reactor spewed radiation over the countryside, contaminating a 200-square-mile area.

South Ural Mountains: explosion of radioactive wastes at Soviet nuclear weapons factory 12 mi from city of Kyshtym forced the evacuation of over 10,000 people from a contaminated area. No casualties were reported by Soviet officials.

1976

nr. Greifswald, East Germany: radioactive core of reactor in the Lubmin nuclear power plant nearly melted down due to the failure of safety systems during a fire.

1979

March 28, Three Mile Island, nr. Harrisburg, Pa.: one of two reactors lost its coolant, which caused overheating and partial meltdown of its uranium core. Some radioactive water and gases were released. This was the worst accident in U.S. nuclear-reactor history.

1984

Dec. 3, Bhopal, India: toxic gas, methyl isocyanate, seeped from Union Carbide insecticide plant, killing more than 2,000 and injuring about 150,000.

1986

April 26, Chernobyl, nr. Kiev, Ukraine: explosion and fire in the graphite core of one of four reactors released radioactive material that spread over part of the Soviet Union, eastern Europe, Scandinavia, and later western Europe. 31 claimed dead. Total casualties are unknown. Worst such accident to date.

1987

Sept. 18, Goiânia, Brazil: 244 people contaminated with cesium-137 from a cancer-therapy machine that had been sold as scrap. Four people died in worst radiation disaster in Western Hemisphere.

1999

Sept. 30, Tokaimura, Japan: uncontrolled chain reaction in a uranium-processing nuclear fuel plant spewed high levels of radioactive gas into the air, killing two workers and seriously injuring one other.

2004

Aug. 9, Mihama, Japan: nonradioactive steam leaked from a nuclear power plant, killing four workers and severely burning seven others.

Information Please® Database, © 2007 Pearson Education, Inc. All rights reserved.
http://www.infoplease.com/ipa/A0001457.html

Labels: air, earth, ozone, science, water

Where is acid rain a problem?

Acid rain is a problem in eastern Canada because many of the water and soil systems in this region lack natural alkalinity - such as a lime base - and therefore cannot neutralize acid naturally. Provinces that are part of the Canadian Precambrian Shield, like Ontario, Quebec, New Brunswick and Nova Scotia, are hardest hit because their water and soil systems cannot fight the damaging consequences of acid rain. In fact, more than half of Canada consists of susceptible hard rock (i.e., granite) areas that do not have the capacity to effectively neutralize acid rain. If the water and soil systems were more alkaline - as in parts of western Canada and southeastern Ontario - they could neutralize or "buffer" against acid rain naturally.

In western Canada, there is insufficient information at this time to know whether acid rain is affecting these ecosystems. Historically, lower levels of industrialization - relative to eastern Canada - combined with natural factors such as eastwardly moving weather patterns and resistant soils (i.e., soils better able to neutralize acidity), have preserved much of western Canada from the ravages of acid rain.

However, not all areas in western Canada are naturally protected. Lakes and soils resting on granite bedrock, for instance, cannot neutralize precipitation. These are the conditions found in areas of the Canadian Shield in northeastern Alberta, northern Saskatchewan and Manitoba, parts of western British Columbia, Nunavut and the Northwest Territories . Lakes in these areas are as defenseless to acid rain as those in northern Ontario. If sulphur dioxide and nitrogen oxide emissions continue to increase in western Canada, the same sort of harmful impacts that have happened in eastern Canada could occur.

Visit the Atlantic region web site for more information on acid rain in this region.

Visit The NatChem Website for information on how to obtain deposition data and maps.

http://www.ec.gc.ca/acidrain/acidfact.html

Labels: air, ocean, water, weather

What causes acid rain?

Acid deposition is a general term that includes more than simply acid rain. Acid deposition primarily results from the transformation of sulphur dioxide (SO₂) and nitrogen oxides into dry or moist secondary pollutants such as sulphuric acid (H₂SO₄), ammonium nitrate (NH₄NO₃) and nitric acid (HNO₃). The transformation of SO₂ and NOx to acidic particles and vapours occurs as these pollutants are transported in the atmosphere over distances of hundreds to thousands of kilometers. Acidic particles and vapours are deposited via two processes - wet and dry deposition. Wet deposition is acid rain, the process by which acids with a pH normally below 5.6 are removed from the atmosphere in rain, snow, sleet or hail. Dry deposition takes place when particles such as fly ash, sulphates, nitrates, and gases (such as SO₂ and NOx), are deposited on, or absorbed onto, surfaces. The gases can then be converted into acids when they contact water.

http://www.ec.gc.ca/acidrain/acidfact.html

Labels: air, ocean, water