BY José Monge, Nick Humphrey, Jerónimo Miranda
With ever-increasing environmental awareness in light of the water crisis in Flint, Michigan, the demand for water-safety testing has risen dramatically, most notably for lead. Lead is an extremely toxic metal that often resides in pipes used in homes built earlier than 1986, which includes about 55 percent of all U.S. homes. There is no safe level of exposure, though the Environmental Protection Agency has set an action limit of 15 parts per billion, making lead an extremely complicated substance to measure precisely.
Currently, only a few companies sell tools to determine the presence of lead in drinking water. The most practical option is a lead test strip that lacks the ability needed to make such miniscule measurements. Furthermore, the test strip only provides a “Y/N (yes or no)” answer, not providing an idea of the level of contamination. As Alison Young from USA Today notes, the current tests are ambiguous, non-reusable, inconclusive, and extremely limited. The second option, which is cost-prohibitive and time-consuming, is laboratory testing, which costs around $50 for one sample and takes around three weeks to produce results.
Testing drinking water for lead is no easy task. Water sources, particularly rivers, are extremely complicated to measure, with hundreds of chemical species present. These chemical compounds are coexisting and ever-changing, and depend on factors such as temperature, pH, and amount of dissolved salts in the water. Given the reactions needed for lead to leach into water, it is possible to see different levels for a single tap, depending on the seasons or even the time of the day.
The consequences of lead poisoning are severe, particularly for children’s brain development, and can persist for three generations. High blood–lead concentration is linked to cancer, liver and kidney diseases, and even criminal behavior.
The lack of a reliable, cheap, multi-use, and accurate test for lead prompted the work of Professor Eli Fahrenkrug’s lab. Over the past two years, several Colorado College students have engaged in the creation of a cheap, accurate, and quick sensor for lead present in water. The project uses different standard materials and processes in conjunction with the principles of bipolar electrochemistry to detect and measure heavy metals, such as lead in water. With the aid of visual-processing software, the signal created from the sensor is processed. By comparing the signal to standards, the amount of lead–or the metal of choice–is then reported.
The project has come a long way since it commenced during Block 7 of last year. The team has developed a mass-production process and made several improvements to the prototype, including the implementation of LED lights, increased accuracy, and a lower cost of production. They hope to finalize the work in the upcoming months and aim to publish the findings in an academic journal.
A couple students from the group decided to take the extra step, founding Advanced Water Sensing, a company that aims to bring tools like this to the public. The students are currently competing in the Big Idea to bring the sensor to the market soon. Their goal is to make the tool accessible for everyone by making it low-cost and widely distributed.