Virginia Tech professor: Flint water still not safe to drink
The water in Flint, Michigan, water is still not safe to drink, said Virginia Tech Professor Marc Edwards, a nationally renowned expert on municipal water quality credited with helping expose the high lead levels in the city’s water.
“The system is slowly improving,” Edwards said. “The more the residents use the water, the faster the system will heal.”
The Flint Water Study team released results of its second round of testing at a news conference Tuesday on Virginia Tech’s Blacksburg campus.
During spring break last month, a team of Virginia Tech civil and environmental engineering students from the College of Engineering worked alongside residents led by Lee-Anne Walters, a former Flint resident and hero-mom, to collect water samples for second round of lead and iron testing.
Two weeks ago, Flint homeowners were sent a personal letter from the Flint Water Study team with their individual results.
While tests reflect improvement, residents should continue to use water filters and drink from bottled water. Testing by EPA, has confirmed that the lead filters distributed in Flint, reduce water lead to below 3 ppb even in homes with the worst lead.
Virginia Tech’s student team had previously worked with Flint residents in a historic sampling in summer 2015 that demonstrated serious lead in water contamination throughout the city. This month marks two years since city officials switched Flint’s drinking water source to the Flint River from the Detroit system.
Last month, the team was able to re-sample 174 out of the original 269 homes that were originally tested in August 2015.
“For sampling, first the water has to rest in the plumbing for at least six hours. The first draw represents the first liter that flows from the tap,” said Siddhartha Roy, a graduate civil and environmental engineering student, as he describes the methodology of obtaining the three samples. “The second sample involves flushing. The tap is turned on and water is allowed to run for 45 seconds. Then the sample is taken. For the third and final sample, the water runs for two additional minutes, then that water sample is drawn.”
The purpose of flushing is to examine whether running the water will clear lead from the pipes.
Analysis of the first draw shows that levels of lead in Flint water at 23 parts per billion, which is still above the 15 parts per billion federal standard as set by EPA. But levels have improved from the 29 parts per billion lead level from the August 2015 testing. More dramatic improvements were observed in flushed water samples, with a fifty percent reduction in lead levels in March 2016 compared to August 2015.
Iron levels in household water have also dropped as a result of the implementation of corrosion control, but with a percentage of homes still exceeding the EPA’s secondary iron standard. On average, iron levels decreased from seven percent to four percent in 2015 and 2016, respectively.
“Since the first round of testing in August, there was a switch to a less corrosive source water. The United States Environmental Protection Agency (EPA) and the state of Michigan implemented improved corrosion control, including extra phosphates,” said Kelsey Pieper a post-doctoral fellow who is working with Edwards and his team to analyze the Flint water samples. “Orthophosphates are corrosion inhibitors that are commonly added to protect pipes, especially in older infrastructure.”
The team conducted a detailed investigation of water use in a few homes that had persistently high levels of lead, revealing many residents are using very little water. For example, two homes with persistent elevated lead levels were using 20 percent to 45 percent of the monthly volume considered typical for U.S. homes. It appears that the abnormally low water use in some Flint households is a result of:
- An effort to reduce water bill.
- Showering once per week for five minutes to reduce the likelihood of rashes and other concerns associated with the water.
- Using bottled water for baths, washing dishes, and other uses.
“Because of what has happened in the past. Because they do not trust and fear for their health and safety … the residents are not using their household water supply in a normal, frequent manner,” said Roy “If such low rates of water use persist, the problems with lead in some homes will take longer to be mitigated.”
Unfortunately, low water use in Flint homes hinders recovery of the water system.
“The delivery of the cure is simply not happening with the system at its current level. The way to recovery is to get more water running through the system.” Edwards said. “Many people believe if they use less water if will be better. That is simply not true.”
Pieper said regular water use is needed to help clean out loose lead deposits and control biofilms within the pipes.
Edwards said Flint residents shoudn’t have any more concerns about taking a bath or a shower than residents of any other city.
Edwards has worked to seek collaborative solutions to the crisis. He serves on Michigan Gov. Snyder’s advisory group and has testified multiple times before Congress on the crisis.
“The EPA has done an outstanding job, demonstrating that the NSF-certified lead filters work very well in Flint, which confirms our own extensive field testing and laboratory experiences,” said Edwards.
Edwards said his Virginia Tech team will continue its partnership with Flint residents. He said the team will recommend to the EPA and state to repeat water sampling in Flint late this summer.