Results of March 2016 Legionella Sampling Event in Smaller Buildings in Flint

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In March 2016, we sampled tap water from 5 homes and 6 small businesses in Flint, with ALL testing culture-negative for Legionella.  We used a standard culture-method often used by hospitals to determine if there is a risk of Legionnaire’s Disease outbreak.  This is good news.  We will be following up with another sampling this summer when the weather is warmer and there is more of a tendency of Legionella bacteria to grow.

We are also examining the water samples we have collected more closely using DNA-based methods.  The DNA methods may help us detect lower levels of Legionella that we couldn’t see with culture and also identify different kinds of Legionella, but the trade-off is that we will not be able to tell the difference between live and dead bacteria.  That is why the culture method is considered the standard for determining risk of getting Legionnaires’ Disease from tap water.

Using the best available science, the sampling we performed in March 2016 showed that if any living Legionella were present, their levels were low the day of testing. There is always some risk of Legionnaire’s Disease from tap water, but our current results from March suggest the risk was not concerning at any of our sample sites in Flint.  We will remain vigilant in our tracking and testing of this potential problem in Flint homes.

Results of Flint Resident Water Lead Sampling (March 2016)

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In March 2016, 174 Flint residents (out of 269 who participated in the original August 2015 sampling of Flint water) re-sampled their homes for lead in drinking water.  The goal was to track possible improvements since the switch back to Detroit water in October 2015 and implementation of improved corrosion control (i.e., extra phosphate added beyond that present in Detroit water) starting December 2015. This work was coordinated by Virginia Tech and was funded by the United States Environmental Protection Agency (US EPA). The following conclusions are based on a preliminary evaluation of this sampling event.

  1. Flint is Not Yet Meeting the 90%’ile Lead Action Level

On the basis of first draw lead levels of samples collected during March 2016, Flint water is still exceeding Federal standards as determined by the EPA 90%’ile action level of 15 ppb.  The 90%’ile lead level in the March 2016 sampling event was 23 ppb which is above the 15 ppb EPA 90%’ile action level. Because the pool of 174 homes sampled is random in terms of the home plumbing profile, and was not selected to include at least 50% homes with lead pipe as required by the EPA for Lead and Copper Rule (LCR) monitoring, our reported 90%’ile lead is probably lower than that which would be determined in an approved LCR sampling event.  Hence, in our opinion, Flint water is not yet meeting the action level. All Flint residents should continue to use bottled water, or Flint water passed through a lead filter, for cooking or drinking until further notice.

Our sampling also demonstrated that water lead throughout the Flint system is highly variable.  Thus, virtually all homes in Flint must be considered at risk, at the present time, for elevated lead in water, unless the homeowner is certain that there is no lead plumbing (i.e., lead service line, leaded brass, or lead solder) in the home.  This means that homes that may have tested very low for water lead in past sampling efforts, must be considered at risk for high lead in water—the advice to use bottled or filtered water, applies to all homes, regardless of past testing results.

  1. Lead Levels Are Lower Now Than in August 2015

On the whole lead in water levels are improving, as indicated by both lower levels of lead, as well as by percentage of water lead samples above 15 ppb.  For example, 90%’ile first draw lead dropped from 28.5 to 22.8 ppb in 2016 versus 2015. The percentage of first draw samples over 15 ppb, dropped from 19% down to 15% comparing 2015 to 2016. For water samples collected after ≈ 3 minutes of cumulative flushing, 90%’ile lead levels were cut in half comparing 2016 to 2015 (i.e., 7.1 ppb versus 3.1ppb).

Lead Results

  1. Iron Levels (and Red Water Complaints) Are Decreasing

The implementation of corrosion control also appears to be reducing iron levels in water.  This is evidenced by a reduced number of homes exceeding the EPA’s secondary iron standard of 0.3 mg/L (for discoloration and red water), which dropped from 7% down to 4% in 2015 and 2016, respectively.

Iron Results

  1. To Speed Up Recovery of The System, Many Residents Will Need to Use More Water

We conducted a detailed investigation of water use in a few homes that had persistently high lead. This investigation revealed that many Flint residents are using very little water.  Two homes with persistent elevated lead problem, were only using 20-45% of the monthly volume considered typical for U.S. homes. Our discussions reveal that this low water use is because many residents are: 1) trying to reduce their water bills, 2) showering only once per week for up to 5 minutes to reduce the likelihood of rashes or exposure, and 3) using bottled water for baths, washing dishes and other uses.

The very low water use rates in some Flint homes, hinders recovery of the system due to the improved corrosion control. Less water use means that the orthophosphate and chlorine added to help improve the water quality and reduce lead and bacteria, are not flowing through the homes as much as is desired. Regular water use is needed to help clean out loose lead deposits and control biofilms within the pipes.  Moreover, occasionally drawing water at a high rate from a tap with unrestricted flow such as a roman bath spout, hose bib or mud sink, will help to achieve velocities inside pipes that are needed to scour deposits that contain lead and iron rust.

In the next few weeks, it is likely that the United State Environmental Protection Agency and/or the state, will recommend a flushing program for homes with input from Virginia Tech, to help with system recovery and pipe cleaning. If implemented, many problems with lead, discolored water and even certain problems associated with bacteria will be brought under control more quickly. Consumers who use very little water, are likely to have more persistent problems, than those who are using more water or who will follow the recommended flushing program.

*Disclaimer: Although the information in this document has been gathered with funding by the United States Environmental Protection Agency, it may not necessarily reflect the views of the EPA and no official endorsement of either the result or recommendations should be inferred.

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Press Release by Dr. Kelsey Pieper and Dr. Marc Edwards

Water utilities ask for clarification on EPA’s memo to publicly make available all information on Lead Service Lines and other “materials inventory” they (utilities) were required to complete under the LCR

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In response to the EPA memo that called for strengthening safe drinking water programs, specifically the Lead and Copper Rule, and that we publicly applauded, the Association of Metropolitan Water Agencies (AMWA) has asked for an important clarification on this particular segment:

To increase transparency in implementation of the LCR by posting on their public website and/or on your agency’s website:
o the materials inventory that systems were required to complete under the LCR, including the locations of lead service lines, together with any more updated inventory or map of lead service lines and lead plumbing in the system.

The letter from AMWA, on behalf of several water utilities, stresses that using the word “inventory” could “certainly create a false impression of the data that many utilities have on hand, resulting in unrealistic expectations from states, customers and the media.” It also “results in the expectation for more precise and comprehensive accounting of lead service lines and fixtures than is required to locate Tier 1 sampling sites (the purpose of doing the “materials evaluation” under the LCR).”

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