Water expert rejects explanation on Flint corrosion control
A water expert who first raised concerns about lead in Flint's drinking water dismissed as "contrived" a city official's suggestion in an email that anti-corrosive phosphates weren't added to the Flint River because of worries that the chemicals would promote bacterial growth.
Environmental engineer Marc Edwards of Virginia Tech told The Associated Press on Wednesday that the Sept. 3 comment by Howard Croft, the former Flint public works director, was "a hindsight explanation" that came shortly after Edwards and his associates went public with warnings that the city's drinking water was dangerous. The river already had sufficient levels of phosphates to nourish bacteria and adding more would have had no effect on them, he said.
"It's very obvious this is a contrived explanation after the fact and it makes no sense," Edwards said.
Flint stopped using treated water from Detroit and switched to the Flint River in 2014 to save money when the city was under state emergency financial management, an interim measure while a new pipeline to Lake Huron is built. The failure to deploy corrosion controls after the switch is considered a catastrophic mistake that enabled lead to leach from aging pipes and reach some homes.
The Michigan Department of Environmental Quality has acknowledged instructing Flint not to use corrosion controls, based on a misreading of federal regulations.
In his email to numerous state and local officials, Croft said a different concern had been identified.
As the city water plant was designed to begin treating river water, "optimization for lead was addressed and discussed" with an engineering firm and the DEQ, Croft wrote. "It was determined that having more data was advisable prior to the commitment of a specific optimization method. Most chemicals used in this process are phosphate based and phosphate can be a `food' for bacteria.
"We have performed over one hundred and sixty lead tests throughout the city since switching over to the Flint River and remain within the EPA standards."
The Associated Press obtained the email from the U.S. Environmental Protection Agency through a Freedom of Information Act request.
Croft did not elaborate on the type of bacteria that anti-corrosive phosphates could promote. His email also didn't say who ultimately decided against using corrosion control chemicals. Without them, the river's highly corrosive water scraped lead from pipes and fixtures for more than a year.
If consumed, lead can cause developmental delays and learning disabilities. Flint has since moved back to the Detroit system. Officials hope anti-corrosion chemicals will recoat the pipes so the water is safe to drink without filters within months.
Edwards told the AP that when his research team sampled Flint drinking water in April 2015, it contained enough phosphate to feed bacteria even though extra phosphates hadn't been added to inhibit corrosion during the previous year. The system's pipes still had residual coating of phosphates from the years when they carried water from Detroit, which used corrosion controls, he said.
"This is a hindsight explanation," Edwards said. "People figured out there was no corrosion control, that children had been lead poisoned, that we were finding very high lead in the water in late August, and people (were) asking questions -- `Why aren't you doing something about this?"'
Croft did not return an email message seeking comment. A DEQ official did not respond to a message seeking comment about whether bacteria had been a concern or discussed with Flint officials.
Croft's Sept. 3 email made no reference to what has been the most frequently mentioned explanation for the decision on corrosion control: The DEQ told city officials that a federal rule on lead and copper pollution required first testing the river water for two six-month periods to determine whether controls were needed. In a Dec. 29 letter to Gov. Rick Snyder, a task force he appointed to investigate the Flint water crisis faulted the DEQ for a "single-minded legalistic" reading of the federal rule.
In an Aug. 31 email obtained by the AP, city utilities administrator Mike Glasgow told Croft that the DEQ had only recently advised adding phosphate as a corrosion inhibitor.
"We originally had this chemical in the design, but the DEQ did not mandate it from the start, they informed us to wait and see the results of our lead and copper to determine if this was necessary," Glasgow wrote. He made no reference to bacteria.
Federal regulators say Michigan officials ignored the EPA's advice to treat Flint water for corrosion-causing elements last year and delayed for months before telling the public about the health risks. State officials say the EPA shares blame for not expressing sufficient urgency.
"We are currently designing an optimization plan with the engineering firm that will be presented to the DEQ and upon approval we expect to have it implemented by January 2016," Croft wrote in his email, adding that according to the DEQ, some cities have taken years to devise such a plan.
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