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  • Zapping water with electricity could save your life.

  • Not something you thought we’d ever say?

  • Were shocked, too.

  • By introducing an electric current into lead pipes filled with a harmless phosphate solution

  • researchers at UC Berkeley were able to rapidly form a protective coating around corroded

  • lead pipes, reducing leaching of this toxic element by roughly 99%.

  • Lead exposure is a huge public health issue, according to The World Health Organization.

  • Paint and dust laced with lead are the most common sources of exposure, but contaminated

  • water is another big issue.

  • In the U.S. alone, over 5,000 water systems violate the EPA’s Safe Drinking Water Act,

  • placing an estimated 18 million people at risk.

  • And lead poisoning is no joke.

  • This chemical element (Pb) can accumulate in our body over time, leading to kidney damage,

  • reduced IQ, increased risk of cancer, stroke, and even death.

  • That’s all thanks to lead’s sneaky ability to mimic and inhibit calcium, break through

  • the blood-brain barrier, and result in the misfiring of neural signals, impairing our

  • ability to learn and develop.

  • Evidence suggests that ancient Romans knew their lead pipes were poisonous, but lead’s

  • dangers weren’t widely re-discovered until the period of industrialization in the 19th

  • century, when reports of lead poisoning began to pick up.

  • Decades of subsequent scientific investigation and their damming findings eventually prompted

  • many governments to distance themselves from sources of lead, like gasoline additives,

  • paint, and piping material, which was favored as a durable and long-lasting material well

  • into the 20th century.

  • But it takes time to redo the plumbing of entire cities, as was made painfully clear

  • when taps in Flint, Michigan began dispensing lead-contaminated water to residents in 2014.

  • One sample even had lead levels reaching 13,200 parts per billion!

  • So...were stuck with all this lead-laden water.

  • Now what?

  • Water doesn’t contain much lead on its own, but it can be corrosive.

  • Once in contact with lead pipes, it can breakdown the metal and cause leaching.

  • To prevent this, inorganic phosphates are commonly added to public water supplies, where

  • they react with positively charged lead ions to form a protective, insoluble mineral scale

  • on the inside of pipes.

  • . But without maintaining tight control of the chemistry, that coating is quickly eaten

  • away.

  • To fix a water supply that’s turned toxic, pipe replacement is by far the best solution,

  • but it’s extremely costly and slow.

  • Case in point: it took two years after Flint’s water crisis erupted for the city’s roughly

  • 170 million dollar pipe replacement program to break ground.

  • And as of 2019, roughly 2,500 lines still need replacement.

  • So is there a better way to zap the situation?

  • ASHOK: In our work, we ask the question, "what can we do to rapidly stop a leaching lead

  • pipe so that the drinking water that passes through it will become safe all over again?"

  • The team specializes in drinking water treatment using electrochemistry, which is the science

  • of looking at how electricity interacts with materials.

  • It starts by introducing a threaded wire down the inside of a lead pipe into a tank of water

  • filled with phosphates, then switching on an electric circuit.

  • At first, the voltage causes lead ions to leach into the water, but as these ions react

  • with the phosphates, they begin to form insoluble lead phosphate.

  • Searching for somewhere to deposit, these minerals begin to settle on the lead pipe

  • itself.

  • ASHOK: As the lead phosphate lines the inside of the lead pipe for a given voltage, less

  • and less current can flow because the lead pipe becomes non-conducting...that's how we

  • know that our process is working.We can reduce the leaching of lead from those pipes by a

  • factor of about 150.

  • We have not tested it yet in the field, but we have a solution that works.

  • Their preliminary results found that once a charge is introduced, a mineral barrier

  • can accumulate on the pipe wall in less than 2 hours, effectively decreasing lead leaching

  • by ~99%.

  • Any part of the lead pipe that’s left uncoated, the current self-tunes to go where it needs

  • to go.

  • As for cost, it’s cheap.

  • There is also a sense of public responsibility in fixing the problem...replacing a pipe costs

  • about 100 dollars a foot if you fold in all the costs.

  • Our goal is to bring that cost down to, maybe, three dollars a foot.

  • Water chemistry varies by a lot.We haven't explored all that space of unknowns...to say

  • "oh yeah, we got the silver bullet.

  • We need to test it out, but we are ready to do that very soon we think.

  • If all goes well, the team plans to try their technique in nearby schools as early as this

  • year.

  • Once refined, this technology could act as a vital stopgap until communities are able

  • to replace lead pipes, as that ultimately remains the best solution.

  • And maybe a 5-star filter for your water tap.

  • Are you excited about this research to stop this toxin from polluting our tap?

  • Let us know in the comments below, and don’t forget to subscribe for more Seeker.

  • I’ll see you next time, thanks for watching.

Zapping water with electricity could save your life.

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B1 中級

鉛中毒仍然是一個巨大的問題,但可能有一個快速的解決方案。 (Lead Poisoning Is Still a Huge Problem, But There Could Be a Quick Fix)

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    林宜悉 發佈於 2021 年 01 月 14 日
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