21.   Bringing in a supply of polluted water would be of very little use to northern China.

22.   But bigger projects to clean up polluted water, one of the most severe border problems, for example, have been delayed or never started.

23.   But the FDA frequently failed to take prompt enforcement action against the foreign companies, whose problems included the use of polluted water and a lack of quality controls.

24.   But whatever promise the new technology holds, there have been several highly publicized illegal discharges of polluted water in Alaska in recent years.

25.   But while MTBE has cleaned the air, it has polluted water, forcing the closure of wells from Maine to California, including several in Massachusetts.

26.   Crews built an interceptor trench and berm at the site to prevent oil and polluted water from the cleanup operation from entering the bay.

27.   Environmentalists have long criticized the sugar industry for releasing polluted water into the Everglades.

28.   For example, it has provided electronic data bases, like toxic release inventories and summaries of advice on limiting consumption of freshwater fish from polluted waters.

29.   Gravity pulls the polluted water through each of the tanks, placed on a descending slope.

30.   He has developed a simple, inexpensive system of disinfecting polluted water with ultraviolet light.