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Road Salt + Hubris = Flint’s Tainted Drinking Water

Thousands of people in Flint, Michigan, have been drinking water polluted with lead for the past couple of years. This whole nightmare scenario could have been prevented if people had simply done their jobs and followed the laws designed specifically to safeguard Flint’s public water supply. Lead is a known neurotoxin, and yet multiple inquiries into the safety of the city’s water were repeatedly dismissed by the very state officials entrusted to uphold federal water quality standards.



In April, 2014, the governor-appointed emergency manager of Flint decided the city was paying too much for its water. For more than 50 years the city of Detroit supplied Flint with copious potable water from Lake Huron. Flint decided it could save money by drawing its water from the Flint River instead. This was to be a temporary solution until Flint finished building its own pipeline from Lake Huron in 2016.

The Flint River water contains eight times more chloride than Detroit’s water from Lake Huron. Chloride corrodes metal pipes. Many older houses in Flint (as elsewhere around the country) have metal pipes, some of which are lead. When lead pipes corrode, particles of lead are flushed out into tap water that people use for drinking, cooking, and bathing. Everyone in the household ingests a dangerous level of lead, because there is no acceptable level of lead to ingest. NOTE: The Flint River itself does not contain lead.

Chevrolet Ave. crossing the Flint River in Flint, Michigan. Source:

Chevrolet Ave. crossing the Flint River in Flint, Michigan. Source:

The Flint River most likely attained its high chloride level from a couple of sources. First, the river was quite polluted to begin with. Flint residents had endured a boil advisory because of elevated levels of E. coli in the water. So officials added more chlorine, which killed the E. coli but resulted in dangerous levels of total trihalomethanes (TTHM), which may cause cancer.

Another cause of the high chloride level is most likely from road salt used to melt snow and ice in the winter. Road salt eventually washes into lakes, streams, and rivers, and seeps into groundwater. In the winter of 2013-2014, Michigan used about 653,500 tons of salt on its roads—among the most in the country. Nationally, the country uses about 22 million tons of salt each year, which breaks down to about 137 pounds of salt for every person in the country. This results in some very real environmental problems.


According to Joseph Stromberg of the Smithsonian, “an estimated 40 percent of the country’s urban streams have chloride levels that exceed safe guidelines for aquatic life, largely because of road salt. . . . [Road salt] can also interfere with a body of water’s natural chemistry, reducing the overall nutrient load. On a smaller scale, highly concentrated road salt can dehydrate and kill trees and plants growing next to roadways, creating desert conditions because the plants have so much more difficulty absorbing water. In some cases, dried salt crystals can attract deer and moose to busy roads, increasing their chance of becoming roadkill.”

Stromberg doesn’t mention the corrosiveness of chloride on plumbing pipes, but water quality engineers are well versed in the topic and its solution, which is known as corrosion control treatment (CCT).

Corroded pipes in Flint. Source:, Min Tang and Kelsey Pieper.

Corroded pipes in Flint. Source:, Min Tang and Kelsey Pieper.

Chloride corrosion can be prevented by adding orthophosphate (such as phosphoric acid) to the water at the water treatment plant. This is a cheap, easy, and standard CCT; it would have cost the city of Flint about $100 a day. The phosphoric acid would have served as a coating for the pipes as the water moved through them, effectively inhibiting corrosion.  The Michigan Department of Environmental Quality (DEQ) specifically and repeatedly told Flint officials and the EPA that CCT was not necessary until they completed two six-month studies of the water. The head of the Michigan DEQ has since resigned .

The Safe Drinking Water Act, administered by the EPA, includes something known as the Lead and Copper Rule. This federal regulation limits the concentration of lead and copper that comes out of a consumer’s tap. It also limits the acceptable amount of pipe corrosion caused by water. The rule was added to the Safe Drinking Water Act in 1991 and applies to every public water system in the country that serves more than 50,000 people. This includes Flint. Evidence suggests that the EPA knew that the Michigan DEQ was violating the Lead and Copper Rule, but did not warn the public.  By the time they had sought counsel on the issue and changed their minds, in November 2015, a class action lawsuit had already brought the topic of the tainted water to the attention of the national media. In the meantime, state EPA director has resigned.

Two individuals deserve recognition for fighting to bring the Flint water crisis to public attention: Flint pediatrician Dr. Hanna-Attisha, who conducted her own investigation into child blood-lead levels, which showed that Flint children had undergone a statistically significant increase in blood-lead levels since the city’s water source changed in 2014. Virginia Tech professor Marc Edwards conducted his own study of the water, which directly contradicted the Michigan Department of Environmental Quality’s claims that its studies showed the water was safe. He came to Flint armed with a grant from the National Science Foundation and ended up becoming the public face of a grass roots campaign to raise the alarm about the public health disaster in the making. Both of these individuals were guided by a sense of moral duty that was so lacking in state officials.

The good guys: Dr. Marc Edwards and Dr. Mona Hanna-Attisha. Source:

The good guys: Dr. Marc Edwards and Dr. Mona Hanna-Attisha. Source:

Flint switched back to Detroit water in December, 2015, but by then the damage was done. The pipes are already corroded; the only fail-safe solution is a mind-bogglingly expensive infrastructure upgrade in a destitute town. Of course, even this won’t help the tens of thousands of impoverished citizens who lack the resources to upgrade the ancient pipes in their homes, or landlords who simply refuse to invest that kind of money on houses that are nearly worthless to begin with.

The rest of the story you probably know: the Michigan National Guard passing out bottled water, the inquiry into Flint’s recent uptick of deaths from Legionnaire’s disease, and appeals to FEMA for disaster assistance. The political blame game is just beginning.

While Flint’s water crisis may have many causes, the road salt issue has largely eluded the media’s attention. For environmentalists, however, it is quite noteworthy. Optimistically, many states recognize the danger of road salt and have begun to explore alternatives, such as molasses, beet juice and cheese brine, which work in temperatures much lower than salt does. Not only might these solutions be better for the environment, they will also result in less wear and tear on your car and the roads. Perhaps it should come as no surprise that the liberal use of road salt in Michigan has not only led to the Flint water crisis, but also is a major factor in the poor quality of Michigan roads. 


Beet juice and cheese brine being tested by the Pennsylvania DOT. GENE J. PUSKAR / THE ASSOCIATED PRESS




Posted on: February 1, 2016, 10:59 am Category: Admin

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