Scientists Now Know Exactly How Lead Got Into Flint's Water

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Scientists Now Know Exactly How Lead Got Into Flint's Water

New report blames corrosion and warns that fixing lead poisoning nationwide will require more work than we hoped.

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For decades, the pipes that brought water to LeAnne Walters’ house did their job unnoticed and safely. But in summer 2014, that changed. Suddenly, Walters found that the water spewing out of her faucets was discolored and foul-tasting; her son would come out of the bath with alarming rashes.

After meticulously sampling her house’s water and testing it with at-home testing kits, Walters discovered that it had lead levels far higher than those considered safe. The chemistry of the water flowing through her pipes had changed profoundly—with toxic results.

Walters tried to contact city and state officials for guidance, but was mostly ignored. That’s when she reached out to Marc Edwards, an engineer at Virginia Tech University who studies water treatment and aquatic chemistry.

With Walters' assistance, Edwards and his team conducted the first major study showing that lead levels in the water of more than a hundred of the city's homes exceeded safe levels in 2014. For a new report, published yesterday in the journal  Environmental Science and Technology , Edwards' team returned to “ground zero” and used chemical analysis of water samples to see just how deep the contamination in Walters’ home ran.

The team concludes that that avoiding lead contamination may require far more work than some think—and may even necessitate a nationwide overhaul of America’s outdated plumbing.

An in-depth chemical analysis of water from the "ground zero" house in Flint's water crisis finds that corrosion is to blame.

The root cause of the Flint lead crisis was corrosion, the new study confirms. For 50 years, Flint had purchased its water from Detroit, its neighbor 70 miles to south. However, in 2014, the cash-strapped city decided to end its agreement with Detroit and start pulling water from the Flint River until a new aqueduct was built. What officials didn't seem to anticipate was the effect that the slightly more acidic water of the Flint River would have on the city's pipes.

Furthermore, officials never used common corrosion control methods that Detroit and many other cities use in their water systems. Those methods include adding phosphates to the water, which help keep lead from dissolving into the water flowing through the pipes. When the city switched water supplies, this rust began to be stripped away, strongly discoloring the water and leaching the large amounts of lead from that rust into the water.

The corrosive water pumping underneath Flint quickly ate away at the protective layer inside the city's old lead pipes, exposing bare lead to the water flowing through them. This lead was the source of the initial contamination, Edwards says. This is what happened in Walters’ house: According to the study, most of the lead appeared to come not from the lead pipe connecting her house to the main line, but from the protective rust that had built up on the house's iron piping over the decades.

Flint switched back to using water from Detroit in October 2015, and is now adding extra phosphates to that water to help reduce lead levels. But these measures amount to just a "band-aid," according to Edwards.

By Ben Panko​​

Read more at: Smithsonian

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