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Government Security News January 2017 Digital Edition

Government Security News January 2017 Digital Edition. Available on the GSN Magazine Website at www.gsnmagazine.com

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Copper, some Lead, that got corroded.<br />

Corrosion occurs when oxidants,<br />

such as DO or Chlorine, react with<br />

elemental metals in the pipes.<br />

Cities no longer install lead pipes.<br />

But older cities such as Flint still rely<br />

on them, usually as water mains in<br />

the street to a home’s water meter. Because<br />

of Lead pipes, some states regulate<br />

the corrosivity of water to deposit<br />

a protective coating on the pipes.<br />

A 1990 report from the American<br />

Water Works Association estimated<br />

there are over 3 million Lead-lined<br />

pipes transporting drinking water in<br />

the Northeastern U.S. alone (6) . According<br />

to EPA, nationwide over 10<br />

million American homes and buildings<br />

receive water from Lead-lined<br />

pipes (7) .<br />

52<br />

So why is Lead<br />

used in water<br />

pipes? The answer<br />

can be found literally<br />

thousands of<br />

years ago in the<br />

first “plumbing”<br />

systems, named for<br />

the word “Lead” in<br />

Latin, “plumbum”.<br />

Tap water in ancient<br />

Rome had 100<br />

times more Lead<br />

than local spring<br />

waters. Lead piping<br />

was used because<br />

of its unique ability<br />

to resist pinhole<br />

leaks while still<br />

malleable enough<br />

to be formed into shapes that deliver<br />

water. Lead was used in many other<br />

common products, such as Tetra Ethyl<br />

Lead in gasoline and Lead-based<br />

paint, until scientific advancements<br />

in the 20th century demonstrated<br />

its toxicity. With passage of the Safe<br />

Drinking Water Act Amendments of<br />

1986, installation of Lead water pipes<br />

was finally prohibited nationwide (8) .<br />

Today utilities treat their water to<br />

maintain a mineral crust on the inside<br />

surfaces of their pipes. This socalled<br />

“passivation layer” protects the<br />

pipes’ metal from oxidants in the water.<br />

The coatings consist of insoluble<br />

oxidized metal compounds produced<br />

as the pipe slowly corrodes.<br />

If the water chemistry isn’t optimized,<br />

the passivation layer may dissolve<br />

and allow mineral particles to<br />

flake off of the pipe’s crust. This exposes<br />

bare metal, allowing the Iron,<br />

Lead, or Copper to oxidize and leach<br />

into the water. Flint water chemistry<br />

was not optimized to control corrosion.<br />

Most importantly, the treated<br />

Flint River water lacked one chemical<br />

that the treated Detroit water had:<br />

Phosphate. Cities such as Detroit add<br />

orthophosphates to their water as<br />

part of their corrosion control plans<br />

because of the formation of Lead<br />

phosphates, which are largely insoluble<br />

and add to the passivation layer.<br />

The entire Flint water crisis could<br />

have been avoided if the city had added<br />

orthophosphates, commercially<br />

available chemicals, used in Detroit.<br />

After just five weeks in the Flint water,<br />

the pipes leached 16 times as much<br />

Lead as those in the Detroit water,<br />

demonstrating just how corrosive the<br />

treated Flint water was. But orthophosphates<br />

aren’t the only corrosion<br />

solution. Some water utilities treat<br />

water so it has a high pH, a high alkalinity.<br />

These conditions decrease the<br />

solubility of Lead carbonates, which<br />

also contribute to the pipe’s protective<br />

mineral layer.<br />

The pH drop over time indicates<br />

that plant operators in Flint didn’t<br />

have a target pH as part of a corrosion<br />

plan. Water utilities usually find a pH<br />

that’s optimal for preventing corrosion<br />

in their system. For example, in<br />

Boston, another city with old Lead<br />

pipes, average water pH held steady<br />

around 9.6 in 2015, according to re-

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