Water Quality Information | Written By Actual Experts
Lead Contamination in Flint, Michigan Drinking Water
Eric Roy, Ph.D. | Scientific Founder
***11/20/2019: Note from Eric. It’s been recently brought to my attention that the July 16, 2015 date on this article may have been incorrect, and that the correct publication date is October 14, 2015. We’ve changed the date listed on the article to reflect this.***
I wanted to take a make our readers aware of a largely unreported disaster that is underway in Flint, Michigan. The residents of Flint, MI are being poisoned by lead in their tap water because the municipality messed up... big time. In this post, I'll focus on the science behind lead contamination, the facts (as we know them) of what happened in Flint, and touch upon another incident in recent history where a similar thing happened.
All water has impurities in it. Most impurities are harmless (e.g. dissolved oxygen, minerals), some are harmful (e.g. lead, arsenic, mercury).
Impurities typically enter tap water in 3 ways:
1. Some are found in the source water (e.g. naturally occurring minerals)
2. Some are deliberately added as part of the treatment process (e.g. chlorine)
3. Some are picked up along the way from the treatment facility to the tap.
Lead is almost never found in source water at dangerous levels, and nobody deliberately adds lead to their water supply, because it's toxic. Lead can, however, be be introduced to tap water as it flows from the treatment facility to the tap.
How is Flint’s drinking water picking up lead in transit?
It’s pretty straightforward: Nearly all homes with plumbing installed before the 1986 use lead-containing solder to join copper pipes. Lead can also be found in residential plumbing fixtures manufactured before 1998. Additionally, some older homes use lead service line pipes to connect water mains to homes. Proper water quality testing (e.g. pH, chloride, toxic metals) and corrosion control practices (e.g. monitoring chloride levels, maintaining a slightly alkaline pH, adding corrosion inhibitors) are what keep residents with older plumbing and service connections safe from lead contamination. This is not unique to Flint. Unfortunately, it's not always done correctly, and residents suffer.
In Flint, as well as other places where high lead levels have leached into municipal tap water (e.g. Washington, DC in the early 2000’s), monitoring and corrosion control measures failed, which allowed lead to dissolve from pipes/fittings/fixtures and poison the residents.
What changed in Flint to cause the lead contamination problem?
In 2014, Flint stopped buying its tap water from Detroit (which has proper corrosion control measures in place), and began collecting their water from the Flint River as part of a plan to switch to a different water supply. During the changeover process, the municipality failed to implement effective corrosion control measures, and the corrosive water allowed lead to leach from lead-containing plumbing.
Because proper water quality monitoring procedures were not in place, the Lead problem was not widely discovered until recently.
Flint has announced that it will resume buying water from Detroit, which gets its raw water from Lake Huron and has proper monitoring and corrosion control measures in place. This is a great first step, but it's important that Flint keeps monitoring their water for lead, because the pipes can continue to leach lead while the corrosion control measures build up the protective layer on the inside of the pipes. The length of time this takes will depend on the degree of corrosion, and whether or not Flint's water will have "boosters" of the anti corrosion chemicals.
Until lead levels drop, residents are being urged to use a quality water filtration system that effectively removes lead. Contrary to some of the information out on the internet... boiling water before use does NOT decrease the amount of lead. It is critical that Flint residents use a filter that effectively removes lead, and also changes the cartridges on a regular basis. I would expect that the filtration capacity (in gallons) for lead would be much lower than the manufacturer claims, because the gallon capacity ratings were determined using water with much lower lead concentrations than what is currently being measured in Flint.
Even though there is a plan moving forward, this type of incident almost certainly caused harm to some residents Flint, and the areas most affected by it were probably homes with older plumbing. Even though lead contamination is odorless and tasteless, it has devastating effects on human health. Since Flint began using the Flint River as a water source, numerous children have tested positive for high levels of lead in blood, and a number of schools have recently shut down water fountains due to high lead levels. When a similar lead contamination issue occurred in Washington DC between 2001-2004, stillbirths shot up during the affected years (Edwards, 2013). As was the case in Washington, DC, the full extent of harm likely will not be realized for several years.
M. Edwards. Fetal death and reduced birth rates associated with exposure to lead-contaminated drinking water. Environmental Science & Technology. Published online December 9, 2013. doi: 10.1021/es4034952.
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