Rising flood waters across the Midwest, in some places the worst in decades, have put hundreds of lives at risk and triggered a state of emergency in Mason City, Iowa. Rising floodwaters have inundated the town, causing a breach in a levee and prompting officials to shut down the water treatment plant.

Dozens of people have been evacuated from their homes, and residents have been asked not to drink the water or to flush their toilets without adequate replacement water. In addition, restaurants have been advised to close. The flooding has caused water to come in over one of the underground storage tanks in the water treatment plant causing water to seep into the tank and contaminating the water, according to a city official. Water also seeped onto the floor of the lower level of the plant, forcing plant workers to shut off the power. The plant has about a day and a half supply of water, and officials expect the plant to be closed for a minimum of two days.

A state team will help Mason City public works assess conditions at the city's water treatment plant and help to bring the plant back into operation as quickly as possible, according to a news release from Iowa Governor Chet Culver.

To read more about the impact of floods, please go to the
Federal Emergency Management Agency

A genetic tool used by medical researchers may also be used in a novel approach to remove harmful microbes and viruses from drinking water. In a series of proof-of-concept experiments, Duke University engineers demonstrated that short strands of genetic material could successfully target a matching portion of a gene in a common fungus found in water and make it stop working. If this new approach can be perfected, the researchers believe that it could serve as the basis for a device to help solve the problem of safe drinking water in Third World countries without water treatment facilities.

The relatively new technology, known as RNA interference (RNAi), makes use of short snippets of genetic material that match -- like a lock and key -- a corresponding segment of a gene in the target. When these snippets enter a cell and attach to the corresponding segment, they can inhibit or block the action of the target gene. This approach is increasingly being used as a tool in biomedical research, but has not previously been applied to environmental issues.

The first prototypes would likely involve a filter "seeded" with RNAi that would eliminate pathogens as the water passed through it. These filters would likely need to be replaced regularly, researchers said, adding that they believe it would theoretically be possible to create a living, or self-replicating system, which would not require replacement.

The researchers are currently conducting additional experiments targeting other regions of the fungus' genome. For their proof-of-concept experiments, they tested RNAi on a non-essential, yet easy to monitor, gene. They are now testing this approach to silence or block genes essential to the viability of the pathogen.

They are also planning to test this strategy in water that contains a number of different pathogens at the same time, as well as trying to determine the optimal concentration needed in the water to be effective.

The experiments were funded by Duke's Pratt School of Engineering.

To read more about this study, please go to:
Duke's Pratt School of Engineering

After a long winter, pool owners around the country are pulling the covers off of their backyard pools and calling the pool guy to get ready for the summer heat. A recent New York Times article took a look at a movement among pool owners to reduce the amount of chlorine in pools or go completely chlorine free, although the pool industry remains skeptical of this practice.

Alternative technologies aren't new, but they have grown in popularity in recent years as people who dislike swimming in chlorinated water become aware of their options.

TechnoPure, a company based in Uxbridge, Mass., makes a system that pumps pool water through a chamber containing coated titanium plates which oxidize and burn off organic waste. Copper and zinc ions sanitize the water, resulting in a pool that's virtually maintenance free in terms of chemicals, according to the company's founder.

Another company, DEL Ozone, based in San Luis Obispo, Calif., makes generators that inject ozone gas into the water as it recirculates, oxidizing bacteria and killing microorganisms. The generators are usually employed as a supplemental sanitizer to reduce reliance on chlorine, but according to the vice president for corporate compliance and market development at DEL, it's possible to rely solely on ozone by using a larger generator and running the recirculating pump continuously. (Energy efficient pumps are available.)

In spite of the popularity and demand for these technologies, industry experts say that no one has come up with as effective a sanitation method as chlorine.

To read more about this story, please go to:
The New York Times

Last week, restaurants removed tomato slices from sandwiches and grocery stores plucked red plum tomatoes from their produce aisles following a nationwide alert that raw tomatoes may have infected scores of people with a rare form of salmonella. Slowly, restaurants and grocery stores have begun to offer tomatoes again, as the FDA closes in on the origin of the contaminated tomatoes.

Food and Drug Administration officials had warned consumers to avoid Roma, red plum and red round tomatoes not attached to a vine because they may carry Salmonella , a bacteria that causes severe abdominal pain and diarrhea. Since April, 228 persons in 23 states have been infected with Salmonella with the same genetic fingerprint.

Salmonella is more frequently associated with poultry, which carry the bacteria. But produce is increasingly a vehicle for salmonella infection as well. Scientists and public-health experts don't completely understand how pathogens contaminate produce. The bacteria can be found in animal feces, which can spread through contaminated water, manure or improper handling.

It can enter tomatoes through the roots or flowers, or through cracks in the skin of the fruit or the stem scar. Once inside, the microbe is hard to kill without cooking. Tomatoes have been linked to 13 outbreaks of Salmonella since 1990, according to the Center for Science in the Public Interest, a Washington advocacy group.

FDA officials have been searching for the source of the outbreak since it was identified in May. Some of the first cases appeared in New Mexico, which announced an investigation May 23.

To read more about the Salmonella outbreak, please go to the:
Food and Drug Administration