Chapter 11 - glossary

 

acid rain
acid precipitation caused by emissions of sulphur dioxide (SO2), nitrogen oxides (NOx), and ammonia (NH3), of which sulphur emissions are the primary source

acidification of lakes and streams
most evident in Norway, Sweden, Finland, and Scotland; seen as clearer water and declining fish populations, due to the precipitation of humic substances, and failure of fish to reproduce in acidic water

acidification of soil
depends on the size of the acid depositions, and the buffering capacity (ability to resist pH changes) of soil and water

caesium-137 (137Cs)
one of the most dangerous radio nuclides emitted from nuclear fission; it has a half-life of about 30 years; the most relevant nuclide of long term concern in the fallout from the 1986 Chernobyl accident; it is absorbed by lichens and fungi

Chernobyl accident
the 26 April 1986 nuclear reactor melt down in the Chernobyl nuclear power plant in the Ukrainian that caused a massive amount of radioactive fallout that spread into Western Europe, and the rest of the world

Convention on Long-Range Transboundary Air Pollution
International agreement from 1979 to reduce and control air pollution in Europe

critical loads
an exposure below which significant harmful effects on sensitive elements of the environment do not occur according to current knowledge, the limits should be set so as to protect even the most sensitive organisms and ecosystems; critical loads have been worked out for acid deposition (acidification) and nitrogen addition (eutrophication)

dry deposition
pollutants coming down in the form of gases and particles, falling directly on vegetation, buildings, or other surfaces

eutrophying air pollution
air pollution mainly caused by nitrogen oxides and ammonia

film detectors
radiation detectors that use photographic film with a sensitive emulsion, that covers the surface of the device, and is darkened by ionising radiation

forest decline
damage seen as discolouring and dead areas on leaves and needles, and defoliation (loss of leaves); older trees are more hard hit than the younger ones; trees in mountain regions have as a rule suffered more damage than those in low-lying parts, coniferous and deciduous species are about equally affected

gas ionisation detectors
radiation detectors that use such gases as argon or methane, or mixtures of argon with methane or neon, in closed tubes as absorbers of electrons; ionising radiation may change a gas molecule into an ion

Geiger-Müller counter
detector consisting of a gas tube, a hollow cathode and a wire anode in its centre, in which ionizing particles cause an electric pulse recorded that is recorded or produces a proportional noise through connection with a loudspeaker; Geiger-Müller tubes are used as hand held devices for routine checking of contamination

nuclear fusion
fusing of hydrogen nuclei to form heavier nuclei emitting at the same time a large amount of energy; not a harnessable form of energy at present

nuclear power
a widely used energy source in the Baltic Sea region, introduced in the 1970s, that primarily depends on fission of uranium to produce nuclear energy

photochemical oxidants
air pollutants formed under the influence of sunlight; ozone usually accounts for more than 90% of the photochemical oxidants

pollutant fallout
pollutants reaching the ground either in their original or a transformed state, wet or dry deposition

radioactive half-life
time for half an amount of a radioactive substance to disintegrate

radioactivity
radiation that originates in the nucleus of an atom

radioiodines 131I
radioisotope with a half-life of eight days that accumulates in the thyroid glands and can cause thyroid and blood cancer

radionuclides
a nuclide that is radioactive

radon
a gaseous element that decays into the "radon daughters," which release alpha and beta particles and are highly dangerous to life forms, especially when inhaled

scintillation counters
detector in which ionizing radiation cause scintillations, light pulses, produced when the radiation interacts with fluors measured by recording of light pulses in a solid crystal of fluorescent material

wet depositions
pollutants coming down in rain, snow, or other forms e.g. fog

volatile organic compounds, VOC
hydrocarbons of which the alkenes, aldehyds, and aromatics are most effective in contributing to the formation of ground-level ozone.