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Center for a Livable Future


April 2010

Rolf U. Halden

Department of Environmental Health Sciences

Rolf Halden

Rolf Halden, PhD, PE is an environmental engineer and researcher with expertise in microbiology, water and wastewater treatment, green chemistry and sustainability.  Although his full-time position is now at Arizona State University, where he is associate professor in the School of Sustainable Engineering and the Built Environment (and heads up a lab in the Biodesign Institute), his work with the Center for a Livable Future dates back nearly a decade.  He maintains an adjunct appointment at the Johns Hopkins Bloomberg School of Public Health in the Department of Environmental Sciences, where he was a co-founder of the school’s Center for Water and Health.

At Arizona State, much of Halden’s work focuses on pollutants in the environment, routes of human exposure, and evaluations of adverse health outcomes.   He frequently partners with federal agencies such as the EPA and CDC, and has served on advisory panels for water quality and environmental monitoring on the local, state and national level.

“I’m an environmental scientist and engineer who conducts research on the movement of chemicals through the environment,” he said.

One of Halden’s top interests is sustainable chemistry—the science of smarter design and regulation of chemicals to minimize adverse health effects and environmental pollution. As he describes it, he realizes that manmade chemicals provide important services to our society but manufactured chemicals are not created equally. Many trigger adverse environmental and human health effects and some do not even perform adequately for the intended purpose. Of principal concern are those substances that are mass produced but highly resistant to biological breakdown – a recipe for environmental contamination, bioaccumulation and persistence.  He sees currently unexplored opportunities to design and manufacture smarter chemicals that are more efficient and more compatible with the environment and living organisms including humans.

One such chemical Halden would like to see used more carefully is triclosan, a common ingredient in antibacterial soap, deodorant, mouthwash, toothpaste, trash bags, textiles and more.  Another is triclocarban, the “active” ingredient of many antimicrobial bar soaps which cause nationwide contamination, as revealed by two CLF-funded studies in 2004 and 2005.

Halden says the widespread use of triclosan and triclocarban in consumer products is primarily a marketing tool, as their non-medical uses have not shown measurable benefits.  Both antimicrobial substances recently were shown to have unwanted properties, including endocrine disruption, bioaccumulation and environmental persistence. Some of the antimicrobials produced and used in the 1960s and 1970s are still detectable today in sediments of the Hudson River and the Chesapeake Bay. Surface waters across the nation show detectable quantities of both substances as a result of their continuous release. A recent assessment of their environmental safety shows that ambient concentrations of triclosan and triclocarban today already exceed critical toxicity threshold values for aquatic and terrestrial biota in some environmental compartments.

“We need to address as a society the incompatibility of many manmade compounds with the natural environment. Environmental longevity is a concern, particularly when adverse effects of high-production-volume chemicals are already well established, as is the case for many organohalogens including the various polybrominated flame retardants and perfluorinated chemicals. Why do we mass manufacture toxic chemicals for which no effective routes of degradation are known? We are creating unnecessary problems for us and future generations,” he said.

In the forthcoming 2010 issue of Annual Review of Public Health, he communicates the need to expand on the accepted notion of the 3Rs and aspire to the more comprehensive concept of 5Rs: reduce, reuse, recycle, rethink, restrain. The fourth ‘R’ challenges individuals and society alike to ‘rethink’ at the systems level, and the fifth ‘R’ encourages the implementation of measures at the policy and governance level that ‘restrain’ wasteful uses of resources, he explains.

Halden’s work is focused on better understanding and managing the connections between manmade chemicals, the environment and associated risks to public health.

“Past mistakes challenge us to transition to consumer products that strike an acceptable balance between their useful lifespan and their environmental persistence,” he said.” Many of today’s products are used on time scales of minutes but will contaminate the environment for centuries or even millennia. Non-biodegradable plastic bottles and perfluorinated consumer products such as Teflon-coated dental floss are just a few examples of unsustainable consumption patterns.”

His prolific career has included work on industrial food animal production, bioremediation of hazardous waste sites, and the characterization of pollutant-degrading environmental microorganisms, human health effects from toxic exposures, the first map of proteins and biomarkers detectable in human fetal cord blood serum, and methods to study renewable bioenergy processes, to name a few topics.

Another of Halden’s notable accomplishments is the invention of a diagnostic tool for studying the treatability of contaminated groundwater right on site in a monitoring well. The in situ microcosm array (ISMA) is a sort of mini underground lab that helps to identify the fastest way to clean up drinking water resources impacted by natural or anthropogenic pollutants.

While Halden isn’t physically at he Johns Hopkins Bloomberg School of Public Health anymore, his important work toward Center for a Livable Future’s goals continues. He’s an important ally in expanding our knowledge base with his research, and in using his stature to influence policy making, to promote sustainable societal lifestyle choices, and to protect human health and environmental quality.