Watershed: The Flint Water Crisis and EPA Lead Exposure Thresholds

The Flint drinking water crisis started in the spring of 2014 when Flint, Michigan changed its public water supply source to the Flint River and officials failed to apply corrosion inhibitors to the water. The lack of corrosion inhibitors caused lead to leach from aging supply lines and contaminate the public water being delivered to homes and business in the community. Since then, it has been discovered that Flint is not alone. Communities in as Philadelphia, Chicago, Milwaukee, Pittsburgh, Baltimore, Trenton, and Boston are all facing a similar “crisis”.  

Whether dealing with soil, air, or water exposure, one has to understand that “contaminants” are everywhere and rarely are humans exposed to a truly pristine environment.  As a result, the Environmental Protection Agency (EPA) and other regulatory agencies have established exposure thresholds for a number of contaminants commonly found in our environment.  These exposure thresholds are thought to be protective of human health and the environment if exposure is at or below a given exposure threshold level.

When dealing with drinking water, the established exposure thresholds are known as a “maximum contaminant levels” (MCLs).  An MCL is the legal threshold limit the EPA has established on the amount of a substance allowed in public water systems under the Safe Drinking Water Act.  The MCL for lead in water is 15 parts per billion (ppb) which means the EPA has established that it is acceptable for humans to consume water with lead levels up to 15 ppb; as most studies show exposure to lead-contaminated water alone would not be likely to elevate blood lead levels in most adults, even exposure to water with a lead content close to the EPA action level of 15 ppb.  For comparison, the 90th percentile reading among the 271 Flint homes tested by researchers was found to contain lead at 27 ppb with one home testing as high as 397 ppb. 

While regulations require public utilities to routinely monitor and test water quality for lead and other contaminants leaving their treatment facilities, the Flint (and other communities) water crisis illustrates the issue that treated (and tested) water supplied by the utility can pick up contaminants along their distribution lines to a home’s water meter.  In the Flint case this was the result of there being no corrosion inhibitors added to the water being distributed (which caused to lead to leach into the water supply from distribution pipes, solder and fittings) so by the time it arrived to a home the water had elevated levels of lead.   There is also an issue with lead entering drinking water after reaching the water meter. The public utility is only responsible for water quality up to the meter.  After reaching the meter, water quality can be impacted by piping, fixtures, fittings and solder inside the home.  Home built before 1986 are the most likely to have lead plumbing.  However, it can be found in newer homes as well. Until two years ago, the legal limit for “lead-free” pipes was up to 8% lead.  In addition, as of January 1, 2014, all newly installed water faucets, fixtures, pipes and fittings must meet new lead-free requirements, which reduces the amount of lead allowed to 0.25%. But that doesn’t apply to existing fixtures, such as what is found in many older homes.  Therefore it is completely possible for water to reach a meter from the utility with no MCL exceedances but reach a tap inside the home with MCL exceedances.

Determining lead levels in water requires a simple water test.  Most local laboratories will provide the adequate sample containers and then will perform the analysis after sample collection.  This testing can also help identify if the issue resides with the utility (pre-meter) or the home (post-meter).  In order to make this determination, water sampling should consist of a “first draw” sample from the tap, preferably after the water has not been turned on for at least 6 hours.  Since this water has sat still for several hours it is representative of the water quality coming from the home.  After collecting this first draw sample, the cold water should be allowed to run for several minutes and a second sample (flush sample) should be collected.  Water in a flush sample is coming from the pipe outside the house (pre-meter) and has not been sitting in the plumbing inside the house.  If elevated levels of lead are found, the source should be eliminated.  This may be as simple as changing out fixtures or as complex as replacing plumbing or an issue with the utility.    For those currently concerned about lead in water, or those awaiting corrective action, the EPA recommends taking the following step

  • Use only cold water for drinking, cooking and making baby formula. Boiling water does not remove lead from water.
  • Regularly clean your faucet’s screen (also known as an aerator).
  • Consider using a water filter certified to remove lead and know when it’s time to replace the filter.
  • Before drinking, flush your pipes by running your tap, taking a shower, doing laundry or a load of dishes.
  • Contact your water system to learn more about sources of lead and removing lead service lines. 

While there was a lot of finger pointing and blame passed around during the Flint water crisis, hopefully the good that can come out of the situation is the awareness concerning lead in drinking water.  We have aging infrastructure (both public and private) and many communities have used the Flint water crises to create awareness and encourage citizens to be proactive when it comes to evaluating lead exposure in drinking water. Since the Flint water crises, August Mack has seen an increase in requests for water testing in schools, homes, businesses and apartments.  While we have not identified a public water supply issues, we have identified numerous interior sources (mainly fixtures and drinking fountains) of lead and assisted clients with a plan to isolate and address the cause of the problem.  If you have additional questions about lead in water – we are happy to share our knowledge with you!    

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