"Scientists have found what seems to be the oldest direct evidence of hot water flowing on Mars during its ancient past," reports Space.com.

"The discovery could further indicate that the Red Planet, despite its arid and desolate appearance today, may have been capable of supporting life long ago." The evidence was delivered to Earth and sealed within the well-known Martian meteorite NWA7034, found in the Sahara Desert in 2011. Due to its black, highly polished appearance, the Martian rock is also known as "Black Beauty." At an estimated 2 billion years old, Black Beauty is the second oldest Martian meteorite ever discovered. However, the Curtin University team discovered something even older within it: a 4.45 billion-year-old zircon grain that harbors the fingerprints of fluids rich in water.

Team member Aaron Cavosie from Curtin's School of Earth and Planetary Sciences thinks this discovery will open up new avenues to understanding hydrothermal systems associated with the activity of volcanic magma that once ran through Mars. "We used nano-scale geochemistry to detect elemental evidence of hot water on Mars 4.45 billion years ago," Cavosie said in a statement. "Hydrothermal systems were essential for the development of life on Earth, and our findings suggest Mars also had water, a key ingredient for habitable environments, during the earliest history of crust formation...."

[T]his new research implies that water in liquid form may have existed on Mars even earlier than previously expected in the planet's pre-Noachian period.

NBC News reports that a newly identified chemical byproduct "may be present in drinking water in about a third of U.S. homes, a study found."

"Scientists do not yet know whether the byproduct is dangerous. But some are worried that it could have toxic properties because of similarities to other chemicals of concern." The newly identified substance, named "chloronitramide anion," is produced when water is treated with chloramine, a chemical formed by mixing chlorine and ammonia. Chloramine is often used to kill viruses and bacteria in municipal water treatment systems. Researchers said the existence of the byproduct was discovered about 40 years ago, but it was only identified now because analysis techniques have improved, which finally enabled scientists to determine the chemical's structure.

It could take years to figure out whether chloronitramide anion is dangerous — it's never been studied. The researchers reported their findings Thursday in the journal Science, in part to spur research to address safety concerns. The scientists said they have no hard evidence to suggest that the compound represents a danger, but that it bears similarities to other chemicals of concern. They think it deserves scrutiny because it's been detected so widely...

David Reckhow, a research professor in civil and environmental engineering at the University of Massachusetts, Amherst, who was not involved with the study, said the finding was an important step. The ultimate goal, he said, is understanding whether the substance is a hazard; he concurred that it was likely toxic. "It's a pretty small molecule and it can probably for that reason enter into biological systems and into cells. And it is still a reactive molecule," he said. "Those are the kinds of things you worry about."
"It's estimated more than 113 million people drink chloraminated processed water in the U.S.," according to a follow-up article by ABC News.

But they also include this quote from Dr. Stephanie Widmer, a board-certified medical toxicologist and emergency medicine physician. "The reality is that no one really knows too much about this chloronitramide and its impact on human health, and more research needs to be done. These disinfecting chemicals have been giving us clean drinking water for decades, so no reason to fear drinking water as a result of this study." Although ABC News tacks on this sentence.

"The study authors suggest, in general, adding a carbon filter to a sink or a standalone pitcher may be a good option for those concerned."

Thanks to long-time Slashdot reader Greymane for sharing the news.