Water Pollution

5. Reducing this is the key to protecting oceans
7. RElease waterborne and airborne toxins that damage fisheries, kill birds, reduce tourism, and poison seafood
11. This process is used to kill disease-carrying bacteria and some viruses
13. "It is a hard truth to swallow, but nature does not care if we live or die. We cannot survive without oceans, for example, but they can do just fine without us."
15. Environmentalist who calls for redesigning the sewage treatment system
16. Bacteria used in secondary sewage treatment to remove dissolved oxygen-demanding organic wastes
17. Processed petroleum products
19. More than 150 cities in the U.S. use natural or artificially created these to treat sewage as a lower-cost alternative to expensive waste treatment plants
20. According to them, improvements to U.S. households regarding drinking water would cost each household an average of $30 a year
21. Oil as it comes out of the ground

1. Tanker that released a huge amount of oil and contaminated 1,500 kilometers offshore
2. Bear the brunt of the inputs of pollutants and wastes into the ocean
3. River's watershed that contains more than half of all U.S. croplands
4. Sewage treatment that uses screens and grit tanks to remove large floating objects
6. This outbreak infected more than 300,000 people and caused at least 3,500 deaths
8. Percent of waste entering the Chesapeake Bay and then flushed into the Atlantic Ocean
9. 85% of the sewage from large cities along this sea is discharged into the sea untreated
10. By itself, primary treatment removes this percent of suspended solids
12. City that is known for its water purity
14. Here, households receive a strip of cloth for filtering out cholera-producing bacteria from drinking water
18. Percentage that scientists estimate of oil that can ever be cleaned up from a major spill