{"id":106340,"date":"2025-02-13T13:10:27","date_gmt":"2025-02-13T19:10:27","guid":{"rendered":"https:\/\/engineering.wisc.edu\/?post_type=news&p=106340"},"modified":"2025-02-13T13:13:48","modified_gmt":"2025-02-13T19:13:48","slug":"for-at-home-tap-water-test-under-development-seeing-red-means-no-lead","status":"publish","type":"news","link":"https:\/\/engineering.wisc.edu\/news\/for-at-home-tap-water-test-under-development-seeing-red-means-no-lead\/","title":{"rendered":"For at-home tap water test under development, seeing red means no lead"},"content":{"rendered":"\n

A group of civil and environmental engineering<\/a> graduate students at the University of Wisconsin-Madison is designing an affordable, easy-to-use test that will allow residents to identify lead in their tap water.<\/p>\n\n\n\n

For the students, it\u2019s literally a golden opportunity to make a big difference in human health: Their system\u2014a color-changing solution that detects lead in tap water\u2014uses gold nanorods attached to silica nanoparticles.<\/p>\n\n\n\n

The solution turns from a wine-red color to colorless when lead is present. PhD student Hanwei Wang says that\u2019s due to an effect called \u201clocalized surface plasmon resonance.\u201d For gold, that means the electrons in nanoparticles\u2014which are smaller than a wave of visible light\u2014resonate with light waves and produce different shades depending on the nanoparticles\u2019 size and shape.<\/p>\n\n\n\n

\u201cWhen lead is present, there\u2019s a chemical reaction happening that etches the gold nanorods, shortening them,\u201d Wang says. \u201cThat changes the color of the water with the solution in it. The higher the concentration of lead, the lighter the water sample\u2019s color becomes.\u201d<\/p>\n\n\n\n

In fact, in the team\u2019s experiments lead turns the red solution clear. The students have used colorimetric sensing, a form of spectroscopy, to evaluate the test results.<\/p>\n\n\n\n

Now the students will work on calibrating the solution. They\u2019ve used pure water for their experiments so far, but Wang notes that tap water isn\u2019t only H2O\u2014especially in parts of the Midwest that have hard water with high mineral content.<\/p>\n\n\n\n

\"\"
These vials show the solution Haoran Wei\u2019s research group is using for lead testing. Red, like on the left, means no lead is present, and it turns colorless when lead triggers a chemical reaction. Photo: Joel Hallberg.<\/figcaption><\/figure>\n\n\n\n

\u201cThe challenge is that mineral ions can cause nanoparticles to aggregate, or clump together, and the sensor won\u2019t work,\u201d Wang says. \u201cWith the design of our gold nanorods, the silica nanoparticles attached to gold nanorods can prevent them from aggregating, even in the mineral-rich tap water like we have in Madison. So we\u2019ve already proved the stability of our sensor in tap water, but we need to keep testing for additional quantitative analysis.\u201d<\/p>\n\n\n\n

When that work is done, they\u2019ll pair it with a smartphone app so that people can easily use it at home. \u201cWe\u2019ve been thinking about how we can develop a sensor using just tap water with a sensing element,\u201d UW-Madison civil and environmental engineering assistant professor Haoran Wei<\/a> says. \u201cThere\u2019s some color change in the sensing element, and we can develop an algorithm to analyze the color change. That means a user could take a photo with the smartphone, and then use the app for analysis.\u201d<\/p>\n\n\n\n

Because the project is in its early phases\u2014it will run through summer 2026\u2014the team is still working on the specifics\u2014for example, how certain aspects of the smartphone app might work. So for now, says Wei\u2014an expert in detecting contaminants in water, and the students\u2019 advisor\u2014it\u2019s primarily a proof of concept.<\/p>\n\n\n\n

The project is funded through the U.S. Environmental Protection Agency<\/a>\u2019s People, Prosperity, and the Planet (P3) Program<\/a>, which is a competition that supports student teams across the United States who are working on ideas for a more sustainable future. It\u2019s one of many ongoing efforts to combat the lingering effects of lead pipes across the country. Though lead pipes were banned across the United States in the 1980s, many places with older construction still rely on them to deliver drinking water. Lead is a potent neurotoxin and can cause significant damage to the brain and nervous system, as well as other parts of the body.<\/p>\n\n\n\n

\u201cUnfortunately, those old pipes sometimes release lead ions into the water, especially when the source water changes,\u201d Wei says. \u201cThat can make the chemistry change, like in Flint, Michigan, when they changed the water source to the Flint River. That led to corrosion in the pipes, which released lead into the tap water.\u201d<\/p>\n\n\n\n

For Wei\u2019s students, who are also studying high lead levels in clusters in major cities and how that impacts local communities, the project is a chance to be a part of a solution for a problem that has lasted for decades.<\/p>\n\n\n\n

Wang sees it as a way to empower ordinary citizens to get information that might otherwise be difficult to obtain. \u201cIt can be difficult to even understand how serious the situation is, because the conventional, gold-standard method for lead analysis is mass spectroscopy. It\u2019s time-consuming and requires trained personnel, so it\u2019s expensive. But we want to make it easier so that if someone is interested in finding out how much lead is in their water, they can just do it in their home.\u201d<\/p>\n\n\n\n

Featured image caption: Civil and environmental engineering assistant professor Haoran Wei, left, and PhD student Hanwei Wang work in a lab on a solution that they\u2019ll use as part of a project to develop a low-cost, at-home method to detect lead in drinking water. Photo: Joel Hallberg.<\/em><\/p>\n","protected":false},"author":48,"featured_media":106342,"template":"","meta":{"_acf_changed":false,"_tec_requires_first_save":true,"_mbp_gutenberg_autopost":false,"_EventAllDay":false,"_EventTimezone":"","_EventStartDate":"","_EventEndDate":"","_EventStartDateUTC":"","_EventEndDateUTC":"","_EventShowMap":false,"_EventShowMapLink":false,"_EventURL":"","_EventCost":"","_EventCostDescription":"","_EventCurrencySymbol":"","_EventCurrencyCode":"","_EventCurrencyPosition":"","_EventDateTimeSeparator":"","_EventTimeRangeSeparator":"","_EventOrganizerID":[],"_EventVenueID":[],"_OrganizerEmail":"","_OrganizerPhone":"","_OrganizerWebsite":"","_VenueAddress":"","_VenueCity":"","_VenueCountry":"","_VenueProvince":"","_VenueState":"","_VenueZip":"","_VenuePhone":"","_VenueURL":"","_VenueStateProvince":"","_VenueLat":"","_VenueLng":"","_VenueShowMap":false,"_VenueShowMapLink":false,"_tribe_blocks_recurrence_rules":"","_tribe_blocks_recurrence_description":"","_tribe_blocks_recurrence_exclusions":"","footnotes":""},"department":[2387],"focus_area":[2382],"news_category":[37,38,39],"news_tag":[1891,2758],"class_list":["post-106340","news","type-news","status-publish","has-post-thumbnail","hentry","department-civil-environmental-engineering","focus_area-energy-sustainability-and-environment","news_category-faculty","news_category-research","news_category-students","news_tag-graduate-students","news_tag-research"],"acf":[],"_links":{"self":[{"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/news\/106340","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/news"}],"about":[{"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/types\/news"}],"author":[{"embeddable":true,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/users\/48"}],"version-history":[{"count":2,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/news\/106340\/revisions"}],"predecessor-version":[{"id":106348,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/news\/106340\/revisions\/106348"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/media\/106342"}],"wp:attachment":[{"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/media?parent=106340"}],"wp:term":[{"taxonomy":"department","embeddable":true,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/department?post=106340"},{"taxonomy":"focus_area","embeddable":true,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/focus_area?post=106340"},{"taxonomy":"news_category","embeddable":true,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/news_category?post=106340"},{"taxonomy":"news_tag","embeddable":true,"href":"https:\/\/engineering.wisc.edu\/wp-json\/wp\/v2\/news_tag?post=106340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}