CES - Water Purification Kit: Key Points

These "key messages" are a set of selected facts about the topic that have been written in a manner to appeal to a general audience. You may want to pick and choose from these statements as appropriate for your audience and topic, or use them as a guide for your presentation.

Problem Statement

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More than half of the wetlands in the United States (excluding Alaska) have already been destroyed. Although scientists have shown that wetlands and streamside riparian zones play an essential role in purifying water, these important ecosystems continue to be cleared, drained, converted to farmland, filled for housing developments and industrial facilities, and used as receptacles for waste. (13,15)

General

•	Natural purification services provide human society with a multitude of economic, health, and recreational benefits. (2,5)
•	Wetlands act as nutrient and contaminant buffers between the land and adjacent rivers, streams, groundwater, lakes, and coastal areas. They can purify water before it reaches the drinking water source. (5,9)
•	Riparian areas along rivers and streams act as "living filters" that intercept, absorb, and store sediments and biogeochemically transform excess pollutants carried in runoff from adjacent lands. (3,8)

Specifics (nutrients, algal blooms, thermal pollution)

•	Wetlands can remove 20–60% of heavy metals in the water, trap 80–90% of the sediment from runoff, and eliminate 70–90% of the entering nitrogen (11). Riparian (streamside) forests can reduce nitrogen concentrations in runoff and floodwater by up to 90% and phosphate concentrations up to 50% (3).
•	Wetlands reduce nutrient loading into water bodies. Excess nutrients often promote undesirable weed growth and algal blooms. Algal blooms are a major cause of fish kills. (2,5)
•	Excessive nutrients (phosphorous and nitrogen) coming from fertilized lawns, golf courses, animal waste, and other sources harm water supplies by prompting excessive algae growth which can lead to drinking water that smells bad, tastes bad, or is unhealthy for human consumption. (1)
•	Excess nitrogen can result in acidification of water and soils leading to long term changes in plant and animal communities and loss of biodiversity. In the Mississippi River, nitrate concentration has more than doubled since 1965. Restoration and retention of wetlands and riparian areas are effective in preventing excess nitrogen from entering waterways. (17)
•	Streamside forests protect rivers and streams from overheating. "Thermal pollution" can harm fish by decreasing the availability of oxygen in the water. Thermal pollution promotes the growth of pathogens and other microorganisms and can trigger large algal blooms. (3)

Economic/Recreation

•	In New York City, the replacement cost of natural water purification services is estimated at $6 to $8 billion in capital costs. By contrast, the cost of maintaining purification services by restoring the integrity of the watershed and thus the purification services is approximately $1 billion. (10,12)
•	The drinkable water supply for a large percentage of the population in the United States comes from watersheds that are protected to some degree. Over half of the human population in the western United States derive water supplies from National Forest watersheds which are managed by the U.S. Forest Service. (14)
•	Drinking water disinfection and treatment can be costly. It is more expensive to prepare polluted water for public consumption that it is to prepare relatively clean water. (13)
•	More than half of all U.S. adults hunt, fish, birdwatch, or photograph wildlife. These activities add billions of dollars to the national economy annually (4). In 1996, an estimated 37 billion dollars was spent in the U.S. on fishing related expenditures alone (16).

Health

•	There is an important relationship between the health of aquatic ecosystems and human health. Natural purification processes can often keep pathogens from reaching drinking water. Once pathogens enter drinking water, pathogens that are harmful to humans can be difficult to remove. (6)
•	More than 100 types of human pathogenic viruses may be present in fecal-contaminated waters. Giardia, an intestinal parasite that is difficult to remove from source water, has been found in higher concentrations in waters receiving industrial and urban pollution than in waters flowing through protected forested watersheds.(7)

Sources

1.	Carpenter, S. R., N. F. Caraco, D. L. Correll, R. W. Howarth, A. N. Sharpley, and V. H. Smith. Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen. 1998. Ecological Applications 8(3):559–568.

2.	EPA 1995. Wetlands Fact Sheet. EPA 843-F-95-001.

3.	EPA 1993. The Role and Function of Forest Buffers In the Chesapeake Bay Basin for Non-Point Source Management. EPA, Annapolis, MD, Chesapeake Bay Program Report. CBP/TRS 91/93.

4.	EPA Office of Water, Wetlands, Oceans, Watersheds: www.epa.gov/owow/wetlands/facts/contents.html

5.	Ewel, K.C. 1997. Water Quality Improvement by Wetlands. pp. 329–344. In G. C. Daily ed. Natures Services: Societal Dependence on Natural Ecosystems. Island Press. Washington DC.

6.	Ewel, K.C. 1988. The Use of Wetlands for Wastewater Treatment. Water Quality Bulletin 13:21–24,32.

7.	Francy, D.S, Myers, D.N, Helsel, D.R. 2000. Microbiological Monitoring for the U.S. Geological Survey National Water Quality Assessment Program. US Geological Survey Water Resources Investigation Report # 00-4018.

8.	Lowrance, R., Todd, R., Fail, J., Hendrickson, O., Leonard, R., Asmussen, L. 1984. Riparian Forests as Nutrient Filters in Agricultural Watersheds. BioScience 34 (6).

9.	Naiman, R.J., Magnuson, J.J., McKnight, D.M., and Stanford, J.A. 1995. The Freshwater Imperative: A Research Agenda. Island Press, Washington, DC.

10.	New York City Department of Environmental Protection, Watershed Agreement: www.ci.nyc.ny.us/html/dep/html/agreement.html

11.	North Carolina State University web site: www.bae.ncsu.edu/programs/extension/wqg/

12.	President's Committee of Advisors on Science and Technology. 1998. Teaming with Life: Investing in Science to Understand and Use America's Living Capital. .

13.	Postel, S., and S. Carpenter. 1997. Freshwater Ecosystem Services. Pp. 195–214. In G. C. Daily ed. Natures Services: Societal Dependence on Natural Ecosystems. Island Press. Washington DC.

14.	Pringle, C. M. 2000. Threats to U.S. Public Lands From Cumulative Hydrological Alterations Outside of Their Boundaries. Ecological Applications 10(4): 971–989.

15.	Sierra Club Wetlands Fact Sheet: http://tamalpais.sierraclub.org/wetlands/

16.	U.S. Department of the Interior, Fish & Wildlife Service, and U.S. Department of Commerce, Bureau of the Census. 1997. 1996 National Survey of Fishing, Hunting, and Wildlife Associated Recreation.

17.	Vitousek, P. M., J. D. Aber, R. W. Howarth, G. E. Likens, P. A. Matson, D. W. Schindler, W. H. Schlesinger and D. Tilman. 1997. Human Alteration of the Global Nitrogen Cycle: Sources and Consequences. Ecological Applications 7(3): 737–750. Ecological Applications 7(3): 737–750.