Fluid Power

Lead in the Pipes, and How It Got There

28 July 2017

Back-scattered electron images of a rust layer cross-section inside pipe samples from Flint. Image credit: Brian Ellis.Back-scattered electron images of a rust layer cross-section inside pipe samples from Flint. Image credit: Brian Ellis.The first direct evidence that untreated water leached lead into the damaged drinking-water system in Flint, Michigan, has been revealed by researchers at the University at Michigan. The findings contradict a regulator's earlier claim that corrosion control chemicals would not have prevented the water crisis.

The team used an electron microscope to study texture and composition of the metal scale layer inside lead service line samples from around Flint. Essentially, this is a layer of lead rust—and it's riddled with holes. Analysis indicated that, on average, the service lines released 18 grams of lead during the nearly year and a half that Flint River water not treated for corrosion control flowed through the system.

"If we average that release over the entire period the city received Flint River water, it would suggest that on average, the lead concentration would be at least twice the EPA action level of 15 parts per billion," said Terese Olson, a U-M associate professor of civil and environmental engineering and lead author of the team’s published study.

Olson cautions that, even after a lead service line is removed, a potential health risk would remain from lead that could be stored in a home’s plumbing. Study co-author Brian Ellis notes that a home’s galvanized steel pipes connected to lead service lines could act as “lead sponges”—holding and releasing particles containing the toxic metals at a later time.

Oxidization (rusting) occurs as lead pipes age; atoms on their surface react with oxygen and other chemicals in the system. Water treatment can prevent the breakdown of the rust layer. Typically, water utilities with lead service lines and corrosive water add orthophosphates, compounds to prevent that breakdown. Flint switched from Lake Huron water to the more corrosive Flint River to save money, but did not adjust its water treatment process.

By analyzing a lead service line from a vacant home not exposed to the corrosive Flint water, the authors hope to verify their prediction of the amount of lead released. The challenge, though, is finding a home with a lead service line that can be dug up—and a water supply that’s been turned off since 2014.

To contact the author of this article, email tony.pallone@ieeeglobalspec.com

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Discussion – 3 comments

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Re: Lead in the Pipes, and How It Got There
2017-Jul-29 1:03 AM

I wonder how much damage that lead in plumbing and paint etc actually effects a person and gives rise to Lead poisoning. A lot of articals seem to be a bit hysterical regarding the effects.

I have grown up through the era when we were surrounded by Lead in many products, In my case lead paint by the bucketful working in a ship yard, household plumbing with lead solder joints and house paints,melting lead weights for scuba diving, soft soldering electrical components and cable lugs, tinning copper buss bars and probably many other items to many to mention.

I do not seem to have suffered any effects from all this contamination, I am not suggesting that it is not a good thing to reduce these contacts with Lead in our environment, it just seems to be a bit over the top and pushed along by certain government departments and university alumni.

Re: Lead in the Pipes, and How It Got There
2017-Jul-29 4:11 PM

I agree with your question of how much effect the lead really had in Flint. The dose makes the poison, as they teach to physicians, and numbers still matter. However, I don't agree with your blaming government and university people for exaggeration. People are already aware of lead's toxic effects, and UM's work to quantify is a much-needed task. Also, reasoning from your own experience is not a general proof; as an example, many chain smokers never get lung cancer, and some nonsmokers do, but it is beyond question that smoking causes cancer. Responsible and replaceable government is needed to protect us against unscience (magic) and private interests.

In the case of Flint, I am concerned that pro-metal people have discouraged the acceptance of free PVC pipe from JM, and have pushed copper instead at the expense of city taxpayers. There is merit on both sides of this conflict, as there usually is in any conflict, and this is not the place to argue details. It is enough if I can stress the importance of numbers and limits, as well as understanding why people think and act as they do, especially when we disagree with them.

Re: Lead in the Pipes, and How It Got There
2017-Jul-29 11:48 PM

It was just a general comment, in this day and age of fake news we should be more discerning re statements from so called speacialists.

One good thing if copper is used it has antibacterial properties which plastic pipes do not have.

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