Government Security News January 2017 Digital Edition

The Chemistry behind the Flint Water Crisis:
Corrosion of Pipes, Erosion of Trust
By George Lane
When Flint, Michigan changed its
water supply in 2014, it initiated a
cascade of chemical reactions inside
decades-old water pipes that caused
Lead to leach into its drinking water,
triggering a major public health crisis.
When Flint used its own river as
a water supply, drinking water contained
a staggering 13,200 parts per
billion (ppb) Lead, almost 900 times
higher than the 15 ppb regulatory
limit set by the Environmental Protection
Agency (EPA). Some water
samples exceeded the EPA criteria
for Lead concentration in hazardous
waste, 5,000 ppb (1) .
Although Lead pipes have been
used for water distribution for over
two thousand years beginning with
the Romans, the use of Lead pipes carrying
water in the United States on a
major scale began in the late
1800s, particularly in larger
urban cities. By 1900, more
than 70% of cities with populations
greater than 30,000
used Lead-lined pipes for
drinking water (2) .
The use of Lead pipes to
carry drinking water was
recognized as a cause of
Lead poisoning by the late
1800s in the United States.
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George Lane
In 1890 the Massachusetts
State Board of Health advised
the state’s cities and
towns to avoid using Lead
pipes to transport drinking
water. By the 1920s, many
cities and towns were prohibiting
or restricting their
use. To combat this trend,
the Lead industry carried out an effective
campaign to promote the use
of Lead pipes, affecting public health
and delaying the replacement of Lead
water pipes (3) .
Normally water managers add
chemicals to water, such as orthophosphates,
to prevent corrosion.
Orthophosphates bond with Lead in
pipes, creating a protective coating
between Lead and water. When that
shield is intact, corrosive chemicals
like Dissolved Oxygen (DO) can’t
interact with the Lead; however, orthophosphates
have to be
added continually or the
barrier breaks down. If the
barrier does break down,
DO combines with Lead
atoms, oxidizing them.
Oxygen takes electrons
from Lead, grabs its Hydrogen
protons, turning
into water, and allows Lead to leach
into drinking water. Once oxidized,
Lead dissolves into the water instead
of sticking to the pipe.
Flint’s water treatment plant did not
add orthophosphates, allowing the
pipes to corrode, and Lead quickly
contaminated the drinking water.
Additionally, Flint River water had
high levels of chlorides, which accelerate
corrosion. There were two other
sources of chloride: Ferric chloride
used in Chlorine disinfection of water
and road salt applied during tough
Michigan winters. Switching
from Detroit’s Lake
Huron to Flint River water
created a perfect storm for
Lead leaching into Flint
drinking water.
A complex brew of acids,
salts, Chlorine and many
other chemicals were involved
in oxidizing Flint’s
metal pipes and releasing
Lead. High levels of Lead in