A cross-cultural team recently developed a new water filtration system for members of the Navajo Nation, one that they hope will make clean water easier to access.
“Water treatment devices are really for the people, so we have to have the people in mind, because without that, either they’re not going to accept the technology, or they’re not going to use it.”
Currently, large sections of the nation lack access to potable water, making communities more vulnerable to diseases such as COVID-19 and gastrointestinal and skin infections. But any potential solutions to this lack of access must be developed in collaboration with local communities, said Navid Saleh, an environmental engineering professor at the University of Texas at Austin and colead of new research published in Environmental Science and Technology.
“Water treatment devices are really for the people, so we have to have the people in mind,” Saleh explained, “because without that, either they’re not going to accept the technology, or they’re not going to use it.”
A Small Solution to a Big Problem
On Navajo land, water contamination has come from many sources. Cold War-era uranium mining has poisoned wells, large uncontrolled landfills have contaminated groundwater supplies, and pesticides from agricultural projects have leached into irrigation reserves. Dangerous levels of pollutants have forced many residents to truck in their water, have it delivered, or collect it from a distant, cleaner source.
These methods of adaptation “mean that water is stored for a long period of time, which can lead to microbial contamination,” said study colead Lewis Stetson Rowles III, an environmental engineer at Georgia Southern University.
Saleh, Rowles, and their colleagues researched the practice of using silver-based nanoparticles to act as tiny purifiers. When a layer of these nanoparticles is applied to certain materials, including ceramic, it releases silver ions, which attack pathogens.
Researchers found two major challenges. First, without any additional coating, the nanoparticles can leave the ceramic before they release the ions, shortening the life span of the filtration. Second, the nanoparticles can mix with chemicals such as chloride and sulfide in untreated water to create a “passive layer,” which reduces the silver’s ability to effectively filter the water.
The scientific challenges for the team then became how to control the release of silver ions from the particles so that a reduction in efficacy didn’t occur and to ensure that the filters could be used for as long as possible.
A Foundation of Trust
Also of great importance was making sure that the filtration technology would be accepted and used by members of the Navajo Nation. When the researchers first met with Navajo representatives in the nearby town of Farmington, N.M., “we didn’t try to come in with any agenda; we really just asked if we could meet and talk,” Rowles said.
The scientists learned how central pottery is to Navajo culture and started working with Deanna Tso, a third-generation potter who lives in Tuba City, Ariz., on the Navajo Nation, to explore how to embed filtration technology into handcrafted Navajo pots. The collaborators decided to use resin from pine trees, abundant throughout the Navajo Nation, to line pots coated with silver nanoparticles.
They found that when the nanoparticles are embedded in the resin, the release of ions is slower and more sustained. The pot materials and construction cost less than $10, and the team’s tests suggest that the coating lasts for approximately 3 years. Then the pots can be recoated.
“So you can own a very beautiful water filter pot, and it could be in your family for decades,” Rowles said.
“This device can work for us,” Tso said.
The integration of Navajo pottery and existing disinfection techniques to create a novel ceramic water filter is a promising technology for addressing water quality, said Otakuye Conroy-Ben, an environmental engineer at Arizona State University.
Importantly, the collaboration involved local knowledge keepers as well as Tso and the scientists, noted Conroy-Ben, a member of the Oglala Sioux Tribe. “Traditional Knowledge should be considered in the context of water due to its significance to Indigenous peoples,” she said. “Coupled with respectful collaboration and reciprocity, culturally centered technological advances could benefit both Indigenous and non-Indigenous populations.”
Tso agreed. But for members of the Navajo Nation to use the device, they first need to hear about it. The project’s next step is to get news of the water treatment pots out through news outlets that residents read and listen to. “Then, the Navajo people can make it happen,” Tso said.
—Jane Palmer (@TJPalmerWrites), Science Writer