We know about the health effects and something of the political circumstances that surround the Flint water crisis, but what about the science? We’re bringing you the science behind the Flint water scandal thanks to professor David Hand, chair of the Department of Civil and Environmental Engineering at Michigan Tech. He specializes in drinking water research.
So how did lead get into the water? Pipes. But not just any pipes. The pipes in many older homes across the state are either made of lead or are connected with lead soldering. According to Dr. Hand, “lead release into the water from the pipe depends on pH of the water and much more strongly on alkalinity of the water. Alkalinity is a measure of the ability of water to resists pH changes. At low pH, the dissolved lead ion is in its most stable form, while lead carbonate is favored at neutral pH values and hydroxycarbonate and hydroxide forms of lead are favored at higher pH values. As the pH lowers, the solubility of lead increases dramatically, especially below a pH of 8.”
So how is that relevant to Flint? “It seems as though the pH of the Flint water may have decreased to a point where the lead scale and lead ion became more soluble, causing the lead contamination of the water.”
Monitoring the water source for these traits is a comment part of the process. Compensating for variations in the water is common practice and is, or should be, controlled for at the source of the water: the Flint river. We know this never happened. The proper actions to neutralize river water were not taken. Hand explains that “the alkalinity and pH of the water can be adjusted to prevent this from happening. However, the best fix would be to replace the lead piping with a safer piping material.”
David is chair of the Department of Civil and Environmental Engineering at Michigan Tech and a board-certified civil engineering member of the American Academy of Environmental Engineers.