Up-to-date information on our collaborative research and citizen science work with the residents of Flint, MI in light of reported water quality issues
Michigan Department of Environmental Quality Director of Communications Brad Wurfel released the following statement to The Flint Journal-MLive:
“We are aware that Virginia Tech researchers are now testing water at various Flint homes for lead levels. We appreciate that Virginia Tech’s team is working on this issue because it brings the public spotlight on an important fact: if you have lead water pipes or plumbing fixtures containing lead in your home, or a lead service connection to the city system, it is very likely you are ingesting some level of lead. That’s just a fact. It’s true whether you live in Detroit, Dowagiac or Decatur.
And in the City of Flint, that fact affects 15,000 or more residences.”
Response: We coordinated a citizen sampling event of homes in Detroit during 2010, and confirmed that Detroit water met Federal Standards—Flint’s water does not.
We agree that 15,000 or more residences in Flint are affected.
Objective: In response to the possible public health problems and infrastructure degradation that is occuring in the City of Flint, we organized a field trip for extensive sampling to better assess water quality concerns. This trip was planned and executed immediately after we finished mailing out 300 lead sampling kits to Flint residents.
Ms. Walters shows Dr. Edwards a used filter that was full of rust seven days into use
Day 2 (Aug 18 2015)
We spent about five hours sampling at 10 sites, most of which are used by the city for their distribution system monitoring. These included the Flint River, a McDonald’s franchisee next to the water treatment plant, and another eight distribution monitoring sites typically used by the city. We took 1.5 L samples for microbial analyses and 500 mL samples to analyze the water temperature, dissolved oxygen and chlorine residual. These samples were processed immediately in our mobile lab. The purpose of this approach was to gather data on water quality at different points along Flint’s distribution system, and to verify similar data that was being collected by the city on the same day.
One of the sampling sites we hit on Aug 18, 2015
Colin pours water into a 10 mL container (scientific term “aliquot”) to measure chlorine using a Hach device
Processing chemical samples and taking measurements in our mobile lab; (L-R) Min Tang, Bekah Martin and Otto Schwake
Dr. Schwake (Otto) processing biological samples for corrosion causing bacteria and opportunistic pathogens
Four of the five members in our FLINTWATERSTUDY van Mobile Lab with (L-R) Rebekah Martin, Otto Schwake, Colin Richards, and Dr. Edwards (Min Tang is taking the picture)
Dr. Edwards getting ready to go wading to collect Flint River samples
Samples collected from the Flint River; The water is brown because of high natural organic matter in the water
Sampling Locations covered in Flint MI on Day 1 (Aug 17)
We then shipped the biological samples overnight to our Virginia Tech labs in Blacksburg, and submitted the E. coli and coliform samples to the Health Department for analysis in the afternoon. We later had dinner with Flint residents and community leaders, and interviewed them about their experiences with Flint water (to be uploaded).
Scientists and community leaders breaking bread together (Aug 18 2015)
FLINTWATERSTUDY Citizen Scientist Leadership poses for a group picture
Day 3 (Aug 19 2015)
We divided ourselves into three groups to maximize sampling. The first group sampled four businesses still on Detroit water, the second sampled four homes that are on Flint water, and the final group sampled two homes where residents had reported health issues. Chlorine levels were also monitored for one place with Detroit water and another with Flint water. We stayed up late to sample what happened to the water at night. The Detroit water had consistent chlorine residual of about 0.5 mg/L whereas the Flint waters had no residuals at 3 am.
We wrapped up sampling around noon, said our goodbyes to Ms. Walters and her family, and set off for the long journey back home.
The sampling sites with Detroit water (A-D) and Flint water (101-104, 11, 13). The water from one resident had white precipitates which needs further investigation.
Primary Authors: Min Tang and Colin Richards
Acknowledgements: Siddhartha Roy, Dr. Marc Edwards
We previously noted the high corrosivity of Flint River water to iron pipe, and the higher incidence of red water and pipe leaks as a result, when compared to the use of Detroit water. At the time, we also mentioned that the Flint River water is much more corrosive to lead plumbing. Scientifically, this is because Flint River has much higher chloride content, which leaches lead from plumbing materials into drinking water.
Experiment: When we visited Flint, we took copper pipe pieces joined with lead solder (old solder is 50% lead by weight) inside them. Lead solder is probably present in plumbing systems 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.
Graduate Research Assistant Christina Devine with the lead corrosion experiment bottles
Christina Devine examines changes in water quality in one of the test bottles
The first thing we noticed was that waters in Test 2 and Test 3 (with Flint River water added) started turning white because of significantly high lead corrosion occurring in them (Figure 1, left). In contrast, Detroit water in the exact same test (Test 1) remained clear (Figure 1, right). Three identical tests are currently being run for aforementioned Tests 1-3 to provide replication increase confidence in the results (only two containers shown in Figure 1).
Figure 1: Samples of lead solder connected to copper pipe in Flint River water with orthophosphate (left) and Detroit water (right). The white suspended particles visible in the Flint River water are tiny lead particles while the Detroit water remained clear
We then collected water samples from every container at the end of Weeks 1 and 2. This means, for each test we took a total of 6 samples. We then used statistics to see what conclusions we could make with confidence.
Figure 2 – Data from Weeks 1 and 2 comparing lead corrosion in Detroit water (left), current Flint water (middle), and Flint water with orthophosphate (right)
The Detroit water is clearly much less corrosive to lead solder than the Flint River water. On average, Detroit water is 12 times (or 12X) less corrosive than the Flint River water currently in use. That is, the current Flint River water leaches 12X 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.
Unfortunately, it does not look like orthophosphate is helping to stop lead leaching when in contact with 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 10 times more lead compared to the same condition using Detroit water. We will continue to run these tests to see if orthophosphate starts reducing the lead present in the test with Flint River 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 (at least based on the first two weeks of testing).
