Test Update: Flint River water 19X more corrosive than Detroit water for Lead Solder; Now What?

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We are now three weeks into our laboratory experiment w.r.t. testing the relative corrosivity of Flint River water versus Detroit water. As the test continues, it becomes a more accurate measure of the relative corrosivity of the two waters. We previously noted, that it would be expected that Flint River water would be much more corrosive than Detroit water, due to its higher chloride content.

Experiment: When we visited Flint, we took pieces of copper pipe joined with lead solder (old solder is 50% lead by weight) inside them. Lead solder is probably present in the plumbing of many Detroit/Flint homes built before 1986 when it was banned from use in drinking water systems. We put the lead solder-copper pipe test pieces in 250 mL containers, and filled them with the following three waters:

Test 1) Detroit water

Test 2) Current Flint River water

Test 3) Current Flint River water with orthophosphate (a typical corrosion inhibitor)

Test 3 was conducted, to see if adding orthophosphate to Flint River water would stop lead corrosion. About 50% of water companies in the U.S. add orthophosphate to their water to control lead corrosion, but it is not currently added to Flint River water.

Results and Observations:

Figure 1 – Data from Week 3 comparing lead corrosion in Detroit water (left), current Flint water (middle), and Flint water with orthophosphate (right)
Figure 1 – Data from Week 3 comparing lead corrosion in Detroit water (left), current Flint water (middle), and Flint water with orthophosphate (right)

From the data shown above in Figure 1, it is clear that Detroit water is much less corrosive to lead solder than the Flint River water. On average, Detroit water is 19 times (or 19X) less corrosive than the Flint River water currently in use. That is, the current Flint River water leaches 19X more lead to the water than Detroit water. This explains why the lead in Flint’s water in our survey, is so high, even when it was low before when Detroit water was being used.

We can actually still see the high lead in the Flint River water test by eye (i.e. as white particles suspended in the water). Lead levels in our test with Flint River water, were slightly above hazardous waste levels (5000 ppb), which is still lower than the worst levels of lead we detected in the home of Flint resident Lee-Anne Walters.

Orthophosphate still does not seem to help stop lead leaching in Flint River water, which is also consistent with expectations based on experiments in high chloride water. There is a slight improvement, but even with phosphate, Flint River water has 16 times more lead compared to the same condition using Detroit water. We will continue to run these tests, but at present it does not seem like orthophosphate will provide a quick answer to the very high lead levels in Flint water.

Conclusion: On a scientific basis, Flint River water leaches more lead from plumbing than does Detroit water as predicted before. This is creating a public health threat in some Flint homes that have lead pipe or lead solder. Unfortunately, adding orthophosphate corrosion inhibitor to the Flint River water, does not solve the lead problem.

 

PRACTICAL IMPLICATIONS

We believe, that in the weeks and months ahead, MDEQ and Flint will be forced to admit they failed to protect public health as required under the Federal Lead and Copper Rule. The question that will then be asked is “What can be done to protect residents?”

Step 1: Issue Scientifically Sound Advice.

The first step is to admit that the water in Flint is not safe for cooking or drinking — a fact that MDEQ still denies. According to MDEQ statements provided to reporter Ronald Fonger this week, which were presented to us for comment, MDEQ’s Brad Wurfel asserts that:

“the issue here isn’t Flint’s water source or water plants. It’s the high number of older homes with lead pipes and lead service connections….Folks who have concerns should get a water specialist to take a look at their home and see what they need to do to achieve peace of mind, because lead and copper are home plumbing problems that no water source can eliminate entirely.”

We note that this is the exact same position that MDEQ and the city took months ago, after Lee-Anne Walters’ child was lead poisoned from exposure to high lead in Flint water. After MDEQ and the City blamed Ms. Walters home plumbing for the problem, an EPA water specialist did come to her home and inspected her plumbing. His finding: There were no lead plumbing sources in her home. How does that finding, provide Ms. Walters and other Flint residents, with “peace of mind?”

Likewise, during our sampling events in Flint homes, we are finding very high lead in other homes with modern lead free plumbing, which again points to city owned lead pipes and corrosive water as the problem.

On the basis of these facts, we consider MDEQ’s position to be both unscientific and irresponsible, and we stand by our recommendations to Flint consumers, that they immediately reduce their exposure to high lead in Flint’s water by implementing protective measures when using tap water for drinking or cooking.

Step 2. Implement Corrosion Control.

The second step will ultimately require some sort of corrosion control treatment to reduce lead in Flint water. Three options are possible as detailed below:

  1. Switch back to the non-corrosive Detroit water. It is our opinion, based on years of experience, that Flint’s lead levels would drop markedly in about one month.
  2. Add orthophosphate to Flint River water. As indicated in this work, orthophosphate will not reduce lead leaching from all lead plumbing sources. On the basis of our extensive experience, we would only expect modest improvements to water lead levels if orthophosphate was added.
  3. Wait for KWA pipeline. If orthophosphate was added to water from the KWA pipeline, it would be about the same corrosivity as Detroit water (Option A). In that case, Flint residents will have to live with the very high lead in their water, until at least one month after the pipeline is connected.

Politicians and residents will ultimately have to look at which of the above options is best for Flint, after weighing feasibility and costs.

Experiments and analysis: Christina Devine

Primary Author: Dr. Marc Edwards

Acknowledgements: Siddhartha Roy

Results from Field Sampling in Flint (Aug 17-19 2015) : Opportunistic Pathogens #2

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Report 5. Additional Testing for Opportunistic Pathogens

During our recent sampling trip to Flint on August 17-19, we collected samples to analyze for the presence of Opportunistic Pathogens (OPs). We reported previously that we did not find evidence to indicate that the OPs Legionella pneumophila, which may cause Legionnaire’s Disease, or Mycobacterium avium, were present in any of the samples we collected.

During our trip, we collected samples from nine businesses located throughout the city of Flint, including eight of Flint’s designated monitoring sites and a business located in close proximity to the drinking water treatment plant, and seven homes of Flint water consumers. For comparison, we also collected water from four businesses that receive water from Detroit. At each of these sites, we collected both water samples and swabs of bacteria growing on the surface within the faucet, known as the biofilm.

Here we report on our results for several additional OPs, alongside the previous results, based on presence of DNA markers specific to each bacterium. Pathogenic species are indicated in red. Mycobacterium spp. represents a genus of bacteria that includes several pathogenic and non-pathogenic species. Vermamoeba vermiformis is of interest because it is an amoeba that may play an important role in the life cycle of some pathogens, such as Legionella pneumophila. In addition, we attempted to culture pathogenic Staphylococcus species from the samples.

Results:

Table 1: Frequency of detection of several Opportunistic Pathogens (shown in red) and additional microbes of interest that are not necessarily pathogenic (shown in black)
Table 1: Frequency of detection of several Opportunistic Pathogens (shown in red) and additional microbes of interest that are not necessarily pathogenic (shown in black)

Table 1 demonstrates that we did not detect quantifiable levels of Pseudomonas aeruginosa, Legionella pneumophila, or Mycobacterium avium in water or biofilm samples collected from any of the sixteen sites in Flint. Acanthamoeba polyphaga was found in the biofilm at 3 sites in Flint. Acanthamoeba polyphaga is an amoeba that is often associated with eye infections of individuals using tap water for contact lens care rather than sterile saline, but has also been associated with skin and respiratory infections. More information on this amoeba can be found here.

Water from each site was also cultured using methods specific to growing Staphylococcus. Only two sites resulted in Staphylococcus growth. DNA from 10% of the resulting colonies were sequenced to identify the species. All sequences were identified to belong to either Staphylococcus epidermidis or Staphylococcus hominis. Both species are frequently found on the skin of healthy individuals and are not typically pathogenic.

Figure 1: Culturing Staphylococcus spp. revealed species of the bacterium that are not typically pathogenic
Figure 1: Culturing Staphylococcus spp. revealed species of the bacterium that are not typically pathogenic
Figure 2: A method known as Sanger Sequencing was used to identify species of Staphylococcus based on unique patterns in the bacterium’s DNA. An example of the sequencing output is shown here. Each colored peak represents a fluorescent signal and corresponds to a different letter in the DNA sequence, which can be seen at the top of the display.
Figure 2: A method known as Sanger Sequencing was used to identify species of Staphylococcus based on unique patterns in the bacterium’s DNA. An example of the sequencing output is shown here. Each colored peak represents a fluorescent signal and corresponds to a different letter in the DNA sequence, which can be seen at the top of the display.

 

Conclusion:

Although the number of samples collected has been small and were collected from each site on a single date, our results do not indicate the presence of pathogenic OPs in Flint water, with the exception of sporadic detection of Acanthamoeba polyphaga in biofilm samples. Overall, this limited sampling, indicates that from a microbiological perspective Flint water does not seem to pose a health risk worse than many other U.S. cities that we have sampled. However, the chronically low chlorine residuals throughout the distribution system, suggest that this issue should be the subject of continued scrutiny.

Additional Notes: The method we used to quantify the pathogens is called quantitative polymerase chain reaction (qPCR). It works by detecting DNA specific to the target microorganisms, making the method very specific, but also very sensitive, as an organism does not necessarily need to be alive or culturable for us to identify that it is present. The minimum threshold of target bacteria, or more accurately the bacteria’s DNA that must be present in the 1-liter samples that we collected is 10 DNA copies per mL or 104 copies in the entire swabbed biofilm. This is the best available and most sensitive method of OPs detection.

Analysis and write-up: Emily Garner

Acknowledgements: Dr. Marc Edwards and Dr. Amy Pruden

Our sampling of 252 homes demonstrates a high lead in water risk: Flint should be failing to meet the EPA Lead and Copper Rule

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Over the weekend, we analyzed all samples shipped to Virginia Tech from Flint to date. Flint residents have already returned an astonishing 84% of the sample kits we sent out (252 out of 300 samples). We will continue to analyze water samples as they are returned. However, mathematically, even if the remaining 48 samples returned have non-detectable lead, our conclusion will not change — FLINT HAS A VERY SERIOUS LEAD IN WATER PROBLEM.

Forty percent (40.1%) of the first draw samples are over 5 parts per billion (ppb). That is, 101 out of 252 water samples from Flint homes had first draw lead more than 5 ppb. Even more worrisome, given that we could not target “worst case” homes with lead plumbing that are required for EPA sampling, Flint’s 90%’ile lead value is 25 ppb in our survey. This is over the EPA allowed level of 15 ppb that is applied to high risk homes. This is a serious concern indeed. Several samples exceeded 100 ppb, and one sample collected after 45 seconds of flushing exceeded 1000 ppb.

We now advise Flint consumers to heed EPA information that advises consumers on how to avoid adverse health effects from exposure to excessive lead in drinking water. The main concern is related to water used for drinking or cooking. With the exception of one home that we sampled which had astronomical levels of lead, the levels of lead detected in Flint were safe for bathing, showering, toilet flushing and watering lawns/gardens.

Until further notice, we recommend that Flint tap water only be used for cooking or drinking if one of the following steps are implemented:

  • Treat Flint tap water with a filter certified to remove lead (look for certification by the National Sanitation Foundation (NSF) that it removed lead on the label), or
  • Flush your lines continuously at the kitchen tap, for 5 minutes at a high flow rate (i.e. open your faucet all the way), to clean most of the lead out of your pipes and the lead service line, before collecting a volume of water for cooking or drinking. Please note that the water needs to be flushed 5 minutes every time before you collect water for cooking or drinking. For convenience, you can store water in the refrigerator in containers, to reduce the need to wait for potable water each time you need it.

We do not issue this warning lightly, and note that our concern is based on several lines of evidence. First, scientifically, we predicted based on past research that the Flint River water chemistry would create a serious lead in water problem. Second, we confirmed the very high corrosivity of the Flint River water for lead in our laboratory testing at Virginia Tech. Third, for some reason that no one has yet explained to us, the Flint River water was introduced into the pipe distribution system without any measures (or even a plan) to reduce its corrosivity. We are therefore very perplexed by recent MDEQ assertions that the situation in Flint is normal. Finally, we have the results of our survey of 252 homes conducted with the assistance of Flint consumers. Because of the very serious and permanent health damage that arises from lead exposure, we feel that this problem requires immediate public health warnings and intervention– we provide that for Flint consumers in this report.

Another mystery that must be examined very carefully in the days and weeks ahead: How is it possible, that Flint “passed” the official EPA Lead and Copper Rule sampling overseen by MDEQ? In our experience, following the EPA site selection criteria targeting homes with the highest risk for lead, the MDEQ sampling should have found much worse results than our sampling. Instead, MDEQ is asserting that the lead levels in Flint are much lower. Hence, we call on the U.S. EPA and others, to conduct a detailed audit of the 2014 and 2015 LCR sampling round overseen by MDEQ in Flint, to determine if it was conducted consistent with requirements of the law.

Primary Author: Dr. Marc Edwards

Samples Analysis: Dr. Jeffrey Parks, Anurag Mantha

Acknowledgements: Siddhartha Roy