ASU professor’s environmental toxins research translates into public health benefits
You may be hard-pressed to find a professional willing to dirty his hands so much to help the earth and its inhabitants as Rolf Halden.
Halden is the director of the Center for Environmental Security at ASU’s Biodesign Institute. He studies wastewater from U.S. cities to zero in on potentially harmful chemicals found in personal products used by millions of Americans. The professor brings expertise in identifying exactly what chemicals we come in contact with, how much our bodies absorb, and where these mass-produced chemicals end up. He then studies their impacts on human health and researches ways to remove them from contaminated natural resources like aquifers, water systems and agricultural soils.
Halden’s work has caught the attention of the Environmental Protection Agency, Congress and other agencies, and he has had a hand in getting certain substances permanently banned by the Food and Drug Administration. His research team has ambitious goals of dramatically improving population health, even completely preventing devastating diseases like cancer.
“Diagnosing cities through the lens of wastewater is a brand-new science that can teach us much about our health and the path forward to a better, more sustainable future,” Halden says. “Where are the opportunities to change behavior or sometimes infrastructure in order to prevent these issues? Let’s go upstream and get to the root cause of human suffering. Ultimately, prevention of disease will return a much higher value than trying to cure it.”
Early findings and beyond
Through the years, Halden’s research teams have uncovered dangerous antimicrobial additives in personal care products, some used as far back as the 1960s. In 2004, while at Johns Hopkins University, his team discovered that triclocarban (TCC) and triclosan, the active ingredients of antibacterial personal care products like bar soap, deodorant and even toothpaste, cause widespread contamination of water resources along the East Coast. Leaking from sewage pipes and evading elimination in the local wastewater treatment plant, these antimicrobial compounds managed to enter urban streams and turned into long-term, persistent pollutants in a river emptying into Chesapeake Bay.
These Baltimore findings, and the conclusion that contamination of drinking water resources likely was a nationwide phenomenon, at first were unconvincing to critics, so Halden’s team began archiving and analyzing samples from wastewater treatment plants across the nation, and even outside the country. ASU is now home to this archive, called the National Sewage Sludge Repository, and to the even larger Human Health Observatory, a specimen bank of global reach. The Halden laboratory monitors samples from more than 180 U.S. cities and 200-plus wastewater treatment plants internationally. It’s the largest archive of its kind in the country.
Halden’s team uses the observatory to create what he calls “human health dashboards” that display the health status of urban populations in real time, informed by analysis of more than 200 chemicals monitored in wastewater and sewage sludge. Halden’s team uses the data to identify health threats and to help implement area-specific solutions, with the aim of preventing epidemics and diseases before they start.
“We train engineers to become ‘physicians’ for city populations, using wastewater diagnostics to assess community health and inform the path forward to a more sustainable future,” Halden says.
In the past decade, Halden’s work on TCC and triclosan hasn’t ceased. He has briefed members of Congress about the harm such pollutants can cause. More recently, he completed studies on the measurable adverse health effects antimicrobials can cause in newborns exposed to TCC and triclosan in the womb. The research also looked at exposure to other ingredients found in cosmetics and personal care products, preservatives like butylparaben and propylparaben, and how exposure to these endocrine disruptors is associated with decreased body weight and body length of newborns.
In September 2016, the FDA banned antibacterial soaps containing TCC and triclosan. Halden calls it a major public health victory, with benefits to consumers and, somewhat surprisingly, even to industry. The antimicrobials are not produced in the U.S., and do not support national manufacturing jobs. Consumers will continue to buy soap and cosmetics.
“Banning bad chemicals makes common sense,” Halden asserts. “It’s good for the consumer and it reduces liability for the industry.”
Halden and his students also have created solutions for measuring toxins and decontaminating water resources. He has developed patented and patent-pending monitoring devices to help continuously and conveniently analyze water resources for the presence of harmful pollutants. One of the ASU team’s inventions is called the “in situ microcosm array,” which is commercially available under the moniker AutoPilotTest and allows environmental engineers to screen different aquifer cleanup methods simultaneously to identify the approach best-suited for turning contaminated groundwater into safe drinking water.
His team also has developed two water monitoring devices that provide better data than conventional methods, while reducing energy requirements and avoiding hazardous waste generation at the same time. One tool from the ASU labs, the In Situ Sampler (IS2), provides accurate information on levels of trace contaminants in drinking water resources without the need for shipping voluminous and heavy water samples across the country from the sampling site to the analytical laboratory.
The other device, the In Situ Sampler for Biphasic water assessment, provides information not only on environmental water quality but also on the mobility and threats posed by contaminants buried in the sediments of inland and coastal waters. This device was used successfully to demonstrate that the pesticide fipronil breaks through wastewater treatment plants to create toxic pollution downstream after deposition in wetland sediments. Fipronil, which is used as the active ingredient in pet products for tick and flea removal, is one of multiple chemicals known to harm honeybee populations that provide pollination services valued at over $15 billion but are on a decline nationally and internationally with causes still being investigated.
Halden’s team also uses micro-organisms as a natural solution to clean up soils impacted by legacy pollutants. Dioxin, a cancer-causing toxin that also has been linked to reproductive and developmental problems, can be broken down by highly specialized soil bacteria. Halden’s team conducted the first whole-genome sequencing of a naturally occurring bacterium capable of using dioxin as its sole food source. When added to contaminated laboratory soils, the bacterium reduced contaminant levels within a few days by greater than 90 percent, demonstrating opportunities of biologically cleaning soils tainted with dioxin and other legacy pollutants.
While his research team continues to make its mark in the fight against harmful toxins impacting human health, Halden says creating lasting changes to policy and product formulations still takes far too much time. In an analysis of over 140,000 scientific studies related to toxin discovery, he learned that it takes, on average, some 14 years from the time of identification of a public health concern to the actual enactment of regulations to protect people.
“Ultimately, prevention of disease will return a much higher value than trying to cure it,” Halden says.
“Fourteen years is, of course, much too long,” he says. “As academics, we need to find a way to communicate our message more effectively and to work more closely with industry and other stakeholders to improve chemical design and consumer safety.”
Originally published at www.azcentral.com on April 13, 2017.