U.S. Water News Online
RESTON, Va. -- From urban growth to infectious diseases and newly identified contaminants in water, greater demands are being placed on our planet's natural resources. Scientists from the U.S. Geological Survey are tackling these new scientific challenges as they emerge.
"The United States and the world face significant challenges in the years to come," said Charles Groat, director of the U.S. Geological Survey. "Over the past century, humans have become agents of significant change to our planet. We have reshaped rivers and coastlines. We have brought new species of plants and animals to places they could never have reached on their own. And, we have increased our vulnerability to the extreme events that are part of Earth's natural processes -- earthquakes, floods, volcanoes, landslides, droughts, and hurricanes."
As the global population continues to grow, he added, people will place greater and greater demands on the resources of our planet, including mineral and energy resources, open space, water, and plant and animal resources. As a result of these changing demands and needs, said Groat, USGS scientists see many scientific challenges for the next century.
Safe, clean water
Safe drinking water is vital to the health of citizens in every community. Reliance on water treatment plants and chlorination is important to safe drinking water but it is clear that strategies must go beyond treatment to protection of water sources. Increasing urbanization of land used as sources of drinking water, microbial pathogens resistant to chlorination, and proliferation of new synthetic chemical compounds that may have adverse health effects, are challenging the effectiveness of treatment technology.
The 21st century will see increased awareness that drinking water supplies are whole systems that include source-water areas, groundwater wells and surface water intakes, treatment plants and distribution systems. USGS scientists are helping communities protect their drinking water sources by designing computer models and other tools and conducting research to help communities identify, manage, and protect source water areas.
Continual development and production of new chemical compounds has dramatically improved food quality, human health, and our daily lives. Increasing knowledge of the close relationship between human activities and the environment has made it clear that the chemical compounds we use can find their way into the nation's water resources. Preliminary results from a USGS study indicate that many compounds commonly used in everyday life are turning up at very low concentrations in streams across the country.
Examples of some of the compounds found to date include acetaminophen, caffeine, codeine, cotinine (a nicotine metabolite), 17b-estradiol (a hormone), and sulfamethoxazole (an antibiotic). For many of these compounds, the USGS study will provide the earliest data on their environmental occurrence in the nation. The impacts of these chemicals on humans or aquatic life, at the low concentrations they are found in the environment, are generally unknown, but the USGS is working in partnership with health and environmental science agencies as the study proceeds.
A major scientific issue in the early part of the 21st century will be the eutrophication of water -- the presence of excess amounts of the nutrients nitrogen and phosphorus that cause increased growth of aquatic plants, which consume the dissolved oxygen in water needed by other aquatic life. Growth of the human population will increase the demand for food. This will in turn lead to further increases in the use of fertilizers, which could put even more stress on coastal areas, as well as freshwater bodies.
USGS scientists are measuring the transport of nitrogen and phosphorus to coastal areas by major rivers to determine how much of the nutrients that enter the streams actually move downstream and how much is lost or transformed to harmless forms.
The nation's water infrastructure
The objectives for the nation's infrastructure of dams, levees, navigation systems and diversions for water were developed between 1930 and 1970, with an emphasis on water for agriculture, electric power, navigation, flood prevention, water for cities and industry and dilution of wastes. These objectives are still valid, but the values and laws under which these systems operate today have a number of added objectives: enhancement of aquatic and streamside or riparian habitat, recreational opportunities and a general desire for preservation of natural environments for future generations.
These challenges will require scientists to collaborate with water managers to predict how changes in the management of our water infrastructure will affect its traditional goals and serve the newer environmental goals. USGS scientists are looking at the physical and biological results of modifying or removing these systems.
Coastal waters -- pristine or polluted?
The earth's seemingly boundless oceans and scenic coastlines have limits. The oceans cannot provide unlimited fish to feed growing populations, nor can they absorb unlimited wastes from human activity. As population growth near and adjacent to the coasts increases water quality and ecosystems are impacted and vulnerable shorelines are eroded. Algal blooms, oxygen deficient zones and Pfiesteria are some of the negative impacts resulting from excess nutrients that end up in coastal waters.
Even after discharge waters are cleaned up, previously deposited contaminated sediments on the sea floor can be "churned up" by storm waves and continue to negatively impact the offshore ecosystems. USGS scientists are locating, characterizing and quantifying how these sediments and associated contaminants are distributed.
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