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