New USGS groundwater studies explain what, when, and how contaminants may reach public-supply wells.

All wells are not equally vulnerable to contamination because of differences in three factors: the general chemistry of the aquifer, groundwater age, and direct paths within aquifer systems that allow water and contaminants to reach a well.

More than 100 million people in the United States receive their drinking water from public groundwater systems, which can be vulnerable to naturally occurring contaminants such as radon, uranium, arsenic, and man-made compounds, including fertilizers, septic-tank leachate, solvents and gasoline hydrocarbons.

The USGS tracked the movement of contaminants in groundwater and in public-supply wells in four aquifers in California, Connecticut, Nebraska and Florida. The importance of each factor differs among the various aquifer settings, depending upon natural geology and local aquifer conditions, as well as human activities related to land use and well construction and operation. Findings in the four different aquifer systems can be applied to similar aquifer settings and wells throughout the nation.

Complete findings, fact sheets, maps and decision support tools are available.

"Our findings can help public-supply well managers protect drinking water sources by prioritizing their monitoring programs and improving decisions related to land use planning, well modifications or changes in pumping scenarios that might help to reduce movement of contaminants to wells," said Sandra Eberts, USGS groundwater study team leader.

Research on the vulnerability of public-supply wells began in 2001. The USGS has also been working since 1991 to study the occurrence of more than 600 naturally occurring and man-made chemicals from more than 1,100 wells used for public supply across the nation. Scientists found that chemicals are frequently detected, often in mixtures, but seldom at concentrations likely to affect human health.

The quality of drinking water from the nation’s public-water systems is regulated by the U.S. Environmental Protection Agency under the Safe Drinking Water Act. Related links to sources of information on public-supply wells are available. USGS studies are intended to complement drinking water monitoring required by federal, state and local programs, which focus primarily on post-treatment compliance monitoring.

Highlights on the four studies:

In the Central Valley aquifer system near Modesto, Calif., the USGS found that agricultural and urban development have enabled uranium to move from sediments to water in the upper part of the aquifer. This water can drain down the well when it is not pumping and enter the lower aquifer. When pumping resumes, contaminant concentrations can be temporarily elevated in water pumped from the well. As a result of USGS findings, public-supply well managers have changed their pumping schedule, which has reduced the amount of contaminated water pumped from the well.

In the glacial aquifer system in Woodbury, Conn., the USGS found that the young age of the water throughout the aquifer makes it vulnerable to contamination from man-made compounds. The USGS also found that dry wells used in Woodbury to capture storm water runoff reroute the potentially contaminated water directly into the aquifer used as a drinking water source. This direct transfer prevents soil and unsaturated sediments near the land surface from filtering out some of the contaminants.

In the High Plains aquifer near York, Neb., the USGS found some contaminants in a public-supply well that seems protected by overlying clay. Nearby irrigation wells have allowed water containing nitrate and volatile organic compounds to leak down from an overlying shallow aquifer into the aquifer that serves as the drinking water source for the public-supply well.

In the Floridan aquifer system near Tampa, Fla., the USGS found that a large percentage of young water and contaminants from a shallow sand aquifer travels quickly along natural conduits until it reaches a supply well in a lower rock aquifer that serves as a drinking water source. Because of these natural conduits, the supply well is vulnerable to the man-made contaminants in the upper aquifer, and the mixing of waters from the two aquifers has caused arsenic concentrations to increase in water reaching the supply well.

Source: USGS

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Learn more about the California study.

Learn more about the Connecticut study.

Learn more about the Nebraska study.

Learn more about the Florida study.

Learn more about public-supply well contamination in a USGS video podcast.

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WASHINGTON - Will 2010 be the warmest year on record? How do the recent U.S. "Snowmageddon" winter storms and record low temperatures in Europe fit into the bigger picture of long-term global warming? NASA has launched a new web page to help people better understand the causes and effects of Earth's changing climate.

The new "A Warming World" page hosts a series of new articles, videos, data visualizations, space-based imagery and interactive visuals that provide unique NASA perspectives on this topic of global importance.

The page includes feature articles that explore the recent Arctic winter weather that has gripped the United States, Europe and Asia, and how El Nino and other longer-term ocean-atmosphere phenomena may affect global temperatures this year and in the future. A new video, "Piecing Together the Temperature Puzzle," illustrates how NASA satellites monitor climate change and help scientists better understand how our complex planet works.

The new web page is available on NASA's Global Climate Change Web site at: http://climate.nasa.gov/warmingworld

For more information about NASA and agency programs, visit: http://www.nasa.gov

Source: NASA

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A few days ago, the presence of armed men clad in camouflaged clothes near the Panex nuclear facility near Armadillo, Texas, caused an alarm and lock-down in the plant until the situation could be properly assessed.

It was a scary event; after all, armed men wearing camo clothes near a nuclear installation does sound scary and it is perfectly understandable that the plat and local authorities preferred to play safe. In the end it was a false alarm provoked by the presence of two men hunting legally with the corresponding permits in a neighbouring property, about three kilometres away from the secure installation. They were employees of the plant itself with a day off, and they were not doing anything illegal, but were they doing the correct thing?

The first conclusion of this strange incident is that it is indeed better to be safe than sorry and that the preventive measures taken were right. Until a real measure of the dangers implied in any sort of emergency is obtained, in such cases it is better to assume the worst-case scenario. That would be, a terrorist attack in concoction for which consequences could be far worse than a technical inconvenience.

But on the other hand, acting just legally will not save these hunters from the wrath of their bosses, who lost probably a small fortune due to the plant lock-down and will in all certainty, receive one or more inspections in their nuclear facility. And having said that, in the end, the incident was provoked by what could be understood as a series of mistakes committed by employees of the plant itself. Enjoying a day off doesn't excuse them from not having reasoned properly, and that could easily translate into questions that inspectors and investigators would put forward to the plant's managers: Do they have employees in such an industry that have little or no common sense?

Three kilometres might look like a great distance; you cannot say that someone is marauding around your home if he stays three thousand metres away, but consider this: Many anti-tank missiles, capable of inflicting serious damage in most types of protected or shielded structures, have such and even larger action ranges, meaning that three kilometres could be interpreted as a comfortable distance from which to point and shoot a lethal heavy weapon in order to perpetrate a terrorist attack.

This shows the difference between a simple employee, even if he or she enjoys a comfortable position at work, and a leader. Our culture turns employees into little more than human machines that perform tasks that robots and computers are still unable to do; the price that is paid for that is lack of independent, intelligent decision. This doesn't mean that employees are fools, rather that they have been domesticated and turned incapable in seeing further than their cubicles. More should be expected from employees, but also from their leaders that shouldn't turn them into mere machines.

These employees didn't tell anyone about their intentions simply because they did not think about the issue; putting safety first wasn't or isn't part of their minds despite the fact that they work in a maximum-security installation. They seem to have been acting thorough their lives as Homer Simpson when he goes to work at Springfield's nuclear power plant. They didn't say anything about what they were going to do simply because nobody asked them to and because they do not have the initiative required to say that on their own.

Moreover: Someone who goes outdoors to climb, hunt, hike, fly or sail should tell someone about his or her plans, just in case. So, in the case of people that should be very careful in their workplace and should have assimilated the same care in their daily actions, such an omission is hard to forgive.

Source: Pablo Edronkin, Andinia.com

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