Matching.
1. the continuous movement of water between the earth's surface and the atmosphere
2. pollutes water sources by dumping wastes in rivers, streams, and oceans
3. the leading cause of water contamination in countries without water treatment plants
4. a source of water pollution caused by the overuse of pesticides and fertilizers
5. caused by an overabundance of organic matter in water supplies
6. the decomposition of organic matter by microorganisms
7. a chemical pollutant that can enter the water cycle through agricultural or domestic use
8. can cause the contamination of underground water supplies if poured on the ground
9. a metal that leaks into water supplies via the soil or aging water systems

putrefaction
petroleum
agriculture
industry
sewage
pesticides
hydrological cycle
eutrophication
lead