Beneath the streets of Boston, two robots named Mario and Luigi inspect the flow of human waste, collecting data on city residents.

The robots are part of the new MIT Underworlds project, which mines urban sewage for information about human health and behavior—a previously untapped resource that could shape the future of epidemiology, say researchers.

Launched by the Senseable City Lab last July, Underworlds could help scientists predict outbreaks, understand causes of chronic diseases and, in mapping the health of different socio-economic brackets in cities, contribute to solution-development and policy-making.

“We soon realized that this interaction with sewage was not really fun.”

“Think about influenza,” explained project head, professor Carlo Ratti. “If we can identify the virus in sewage before hospitals or clinics are aware of an outbreak, they can prepare and direct resources to most effectively respond, and potentially even mitigate a large city-scale outbreak.”

The prototypes, which are currently being tested in Boston and Cambridge, can also scan sewage water for toxins released by industry as well as for certain human biomarkers and chemicals which signify non-communicable diseases like obesity and diabetes.

“In this way,” explained Ratti, “we can begin to evaluate public health policy by understanding the downstream effects of, say, a sugar tax in a city. By looking at all this data together with demographic and urban land use data, we can begin to understand how our urban environment and other external factors affect our health. We’re hoping to build a new kind of urban health census.”

Courtesy Underworlds Meet Luigi.

Luigi ventures into a Boston-area sewer.

The US Environmental Protection Agency has described Underworlds as an “extremely ambitious and pioneering” attempt that—if successful—represents a “seminal advancement in the prospects for quickly and inexpensively monitoring public health in real time.” Initially, the project consisted of a bottle taped to the end of a 20-inch pole, which researchers plunged into a manhole to scoop out their “sample.”

“We soon realized that this interaction with sewage was not really fun,” said Ratti, describing how the team went on to develop a street-level pump connected to a car battery which was “quite messy” before designing Mario, the first automated sampler.

Luigi (a faster, slimmer, and more cost-effective version of Mario) hangs from below the manhole cover at water level, where it sucks in sewage and studies it for viral and bacterial DNA. The team is working on a GPS system to control Mario and Luigi’s movements remotely, as well as retrieve real-time environmental data like flow and temperature.

While sewage analysis is usually conducted in treatment plants, the Underworlds robots are no more than 15-minutes’ journey from a toilet flush, meaning samples are fresher and much more closely resemble waste samples collected from individuals. “As a result, we can detect chemicals (for example, pharmaceuticals) as modified by the human liver, giving us 100% certainty that those chemicals were ingested by humans or humans were otherwise exposed to them,” explains a team spokesperson. The proximity also means common foods are easily detectable based on area—the team analyzed the top 10 plant-based foods in their sample regions, finding rice, wheat and beans to be among the most common.

“But what we didn’t expect was finding pomegranate on the list!” said Ratti. “That’s very Cambridge…”

Courtesy Underworlds Dropping Luigi into the sewer.

A live visualization of data can be viewed on the Underworlds website, showing the number and type of virus in sample water, such as the herpes-causing simplex and the chickenpox-related cytomegalvirus—bacteria and chemical visualizations are still to come. The team hopes the pilot project, being run in conjunction with Massachusett’s Department of Public Works, will lead to a larger-scale front-end data platform for visualizing the health of particular neighborhoods.

Underworlds is also collaborating with the Kuwait Institute for Scientific Research and Kuwait University to develop the platform all full-scale and in the future, implement the system in Kuwait.

Underworlds is part of a broader MIT agenda to use technology to better understand cities; after the Senseable City Lab launched 12 years ago, researchers were among the first to analyze mobile communication data for urban social patterns.

“Today, meta-genomics promises a similar opportunity,” said Ratti. “The Underworlds project aims to use waste to open up a new world of information on human health.”