Water Quality Revisited
By Cynthia Weber
Recent research is offering alternatives for cleaning up water supply, and new apps may put the power of monitoring into the people’s hands.
Brown tap water. Corrosive auto parts. What do they have in common? In Flint, Michigan, the common denominator was a high chloride concentration in the water. General Motors (GM) first identified local water quality issues when they realized automobile parts from their Flint plant were corroding at a faster pace than usual. Their investigation led them to the source: the Flint River. Previously, the water that flowed to the GM plant hailed from the Detroit water system, which originated from Lake Huron and was treated with polyphosphates. However, the Flint water not only had a lower pH level but was left untreated, and this ultimately led to the iron-corrosion problem.
Unfortunately, GM’s investigation was not looking for lead. Although the company reported their findings to the Flint Water Authority when they switched back to Detroit water in late 2014, city and state officials did not connect the dots between the more acidic water with high levels of chlorides, and the city’s old lead pipes that traveled from the mains to the local buildings and residences. The untreated Flint water moving through the pipes was essentially stripping the pipes’ protective scale, leaching the lead directly into the city’s water and delivering it to residents’ homes. Not until October 2015 was a public health emergency declared, exposing hundreds of Flint residents, many of them children, to dangerous levels of lead for a year and a half.
Aging water systems are a concern nationwide according to a 2016 study by the National Resources Defense Council, which found that more than 5,300 U.S. water systems are in violation of various federal lead standards. Replacing current infrastructure is a must. For Flint, the lead problem was exasperated by low population in a city that was originally built for many more people and more manufacturing; because demand was less the water moved slowly through the pipes allowing time for the water to become even more corrosive. This is just one of many signals that multiple U.S. city systems need to be adapted for current population levels and use.
However, updating infrastructure will take time and money and therefore, alternate solutions are urgently needed. In response, researchers at Rutgers University are working to develop crystals that could detect and capture heavy metals such as lead and mercury [1]. These small, glowing crystals, known as luminescent metal-organic frameworks (LMOFs), would basically function as miniature reusable sensors and traps.
Working with intense X-rays at Lawrence Berkeley National Laboratory, researchers probed crystal structures in an effort to determine how they bind to heavy metals. Using the lab’s Advanced Light Source (ALS) to study individual crystals, the research team mapped the crystal’s 3-D structure with atomic resolution, revealing a grid-like structure containing carbon, hydrogen, nitrogen, and zinc atoms framing open channels. This open framework enables heavy metals to enter the channels and chemically bind to the MOFs, turning off the fluorescence; the crystal’s rather large surface area allows for a greater intake of contaminants. One type of LMOF tested was able to trap 99 percent of mercury from a test mixture, performing above other MOFs in detecting and adsorbing toxic metals. Tests have also shown the crystals to be selective, connecting strongly to mercury and lead but weakly to other non-hazardous metals such as magnesium, and the LMOFs can be cleaned and reused up to three times, offering a potential low-cost solution to lead water contamination in the near future.
Finally, technology is also placing the power of knowledge into individual’s hands. With funding from Google, researchers in the computer sciences at the University of Michigan (UM) Flint and Ann Arbor campuses developed an app and website that will help the community manage the ongoing water crisis [2]. Mywater-Flint allows users to access a city-wide map of where lead has been found in drinking water, track where infrastructure has been replaced or is undergoing work, and view detailed instructions for how to test water for lead, among other features. This project is part of a partnership between Google, UM-Flint, and the Michigan Data Science Team, led by assistant professor of electrical engineering and computer science at UM-Ann Arbor, Jacob Abernathy, who serves as faculty advisor. The goal is to develop predictive software that evaluates risk of lead contamination, relying on publicly available data, in the hope of providing both officials and the public with tools to help manage the current water crisis. Software platforms such as this also have the potential to be adapted to other communities.
If there is another lesson to be learned here, the situation in Flint highlights the importance of “connecting the dots” — viewing the entirety of the situation rather than discreet parts. Had officials been cognizant of the relationship between iron corrosion and lead release under similar conditions, the water quality situation might have been more quickly addressed. With similar water crises destined for other American municipalities, research on predictive software and new approaches to removing toxic chemicals are warranted, as well as the recognition of early warning signs. This again provides an example where collaboration among life sciences professionals is not only essential, but could in fact be life-saving.
References
- Lawrence Berkeley National Laboratory. “Glowing crystals can detect, cleanse contaminated drinking water: X-ray study explores atomic structure of tiny traps for heavy metals.” ScienceDaily. 29 November 2016. www.sciencedaily.com/releases/2016/11/161129124512.htm
- “Google-funded Flint water app helps residents find lead risk, resources.” Michigan News. 8 December 2016. http://ns.umich.edu/new/multimedia/videos/24394-google-funded-flint-water-app-helps-residents-find-lead-risk-resources