pollution

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Across
  1. 2. the material left behind after the treatment of sewage- it is often toxic
  2. 3. waste from nuclear power plants
  3. 5. sewage can be treated with this method
  4. 7. toxic gas released from automobile emissions
  5. 9. contamination of water by fluoride
  6. 10. a poisonous element
  7. 12. where arsenic deposits are often present
  8. 13. excessive amounts of eroded soil particles carried by flowing water
  9. 14. gas which causes air pollution
  10. 16. most common disinfectant
  11. 18. running large quantities of water through soil to leach out pollutants
  12. 20. a unit for measuring the intensity of sound
Down
  1. 1. bacteria and other micro-organisms are used to clean up the soil in this process
  2. 4. sediments reduce this process
  3. 6. sludge is often.
  4. 8. acids, salts, heavy metals etc. are _________ chemicals
  5. 11. one of the main pollutants of air
  6. 15. type of cancer caused by arsenic
  7. 17. pesticide present in bottled water
  8. 19. pesticides and fertilizers cause_______pollution