DEFINITIONS

• IONISING RADIATION

  radiation that can knock electrons out of the atoms of a substance
• HALF- LIFE

  time it takes per half the nuclei to decay in a radioactive sample
• EXPOSURE

  how long a person is exposed to radiation
• CRITICAL PATHWAY

  route that radiation takes through the ecosystem
• ALPHA RADIATION

  radiation which has a low penentration power, travels short distances
• CRITICAL GROUP

  groups of people who are considered particularly likely to be exposed to certain forms of pollution
• GAMMA RADIATION

  radiation which has high penetration power and travels large distances
• ACUTE

  small intense or severe
• CHRONIC

  persistent or recurring