Recent News

Passive Samplers Tackle PCB Flux

May 10, 2019

Project 4 researchers have developed a method to measure the movement, or flux, of polychlorinated biphenyls (PCBs) from water to air using passive sampling devices.The team, led by Andres Martinez, Ph.D., and Center Director Keri Hornbuckle, Ph.D., demonstrated that simple and cost-effective passive samplers could be used to overcome this challenge. By improving how PCB flux is measured, researchers can better understand and predict water- and airborne exposures to PCBs in communities living near contaminated waterways.

The team used a dual-sampling system of polyurethane foam passive air (PUF-PAS) and low-density polyethylene (LDPE) water samplers to simultaneously measure PCBs in water and surrounding air. PUF-PAS and LDPE samplers are frequently used to capture and measure persistent organic pollutants like PCBs. Using measured water and air concentrations over time, they were able to calculate the direction and magnitude of PCB flux. According to the authors, passive sampling devices like these can reduce uncertainty and improve the sensitivity and accuracy of analytical methods.

The research was reported in the January 2019 edition of Environmental Pollution.

Above image is courtesy of Andres Martinez.

Release of Environmental Data to Public Data Repositories

May 10, 2019

SRP investigators and the ISRP Research Translation Core began placing complete environmental data sets in the public data repository PANGAEA. Project 4 investigator Dr. Andres Martinez and colleagues published two studies of polychlorinated biphenyls (PCBs) in Lake Michigan. The first study reported a new method to measure the emissions of airborne PCBs from the Indiana Harbor and Ship Canal (Martinez, A., A.M. Awad, N.J. Herkert, and K.C. Hornbuckle, Determination of PCB fluxes from Indiana Harbor and Ship Canal using dual-deployed air and water passive samplers.

The second study concerned the exchange of gas-phase PCBs in south-western Lake Michigan (Boesen, A., A. Martinez, and K.C. Hornbuckle, PCB congener data of gas-phase, dissolved water, air-water fluxes in southern Lake Michigan, 2010. PANGAEA, (dataset in review), Supplement to: Boesen, A et al. (in review): Instantaneous Air-Water PCB fluxes from Southern West Lake Michigan Revisited. Environmental Science and Pollution Research. 2019, PANGAEA). This study evaluated air and water samples collected simultaneously on an EPA research vessel in 2010. Both studies generated large datasets of PCB congeners in air and water, and large datasets of the associated meteorological, hydrological, and geographic metadata.  These datasets were published separately from the journal in PANGAEA and are available to the public without charge.

We believe this is the first public release of environmental measurements of all 209 PCB congeners and the associated metadata using a non-governmental data repository.

Project 6 Outreach in East Chicago

May 10, 2019

Project 6 Leader Dr. Peter Thorne, staff member Barb Mendenhall, and trainees Ezazul Haque and Tuo Lan attended an EPA meeting in East Chicago, Indiana on April 6, 2019. The EPA debriefed East Chicago residents on its planned cleanup activities for the U.S.S. Lead Superfund site, which encompasses East Chicago’s Calumet neighborhood. During the 2019 season, the EPA plans to remove contaminated soil from properties in both East Calumet and Calumet neighborhoods. Project 6 has been studying airborne PCBs and other contaminant exposures for residents in East Chicago and Columbus Junction since 2010.

During the past several years, it has been meeting regularly with the East Chicago Community Activist Group to hear and address the needs of the community.

Picture courtesy of Kyle Telechan/Post-Tribune.

Human Metabolism of PCBs to OH-PCBs in Human Liver Cells

May 10, 2019

ISRP trainee Eric Uwimana and colleagues from ISRP Synthesis Core, Project 1 and Project 3 investigated the biotransformation of PCB 91 to OH-PCBs by human liver microsomes (HLMs) Human liver microsomes atropselectively metabolize 2,2',3,4',6-pentachlorobiphenyl (PCB 91) to a 1,2-shift product as the major metabolite. The unexpected, preferential formation of a 1,2-shift product and the variability of the OH-PCBs profiles in experiments with individual donor HLMs underline the need for further systematic studies of the atropselective metabolism of PCBs in humans.

Uwimana also examined the metabolism of chiral PCBs and the role of several different P450 enzymes found in the human liver. Uwimana first predicted the likely enzymes involved in producing metabolites of four PCB congeners using ADMET Predictor and MetaDrug. He then confirmed the predictions by incubating the four PCBs with the most likely human P450 isoforms. Results demonstrated that chiral PCBs are metabolized in a congener-specific and atropselective manner to OH-PCBs by CYP2A6, CYP2B6, and CYP2E1 in humans.

PCBs Found in Kitchen Cabinets

May 10, 2019

In a study released in Environmental Science & Technology, Dr. Keri Hornbuckle and trainees Jacob Jahnke and Nick Herkert discovered that kitchen cabinets built within the last five years emit PCBs into the air. The researchers tested sixteen homes with passive air samplers and found PCB- 47, PCB-51, and PCB-68 to account for up to 50% of measured indoor PCBs. They suspect the PCBs are byproducts of sealants used on the cabinets.

The study has garnered extensive coverage. It has been covered by an American Chemical Society press release, Environmental Health News, UPI, US News, and BuzzFeed. In England, it has been covered by the Daily Mail, Times of London, and the Mirror.

The above picture is courtesy of Ablokhin / Getty Images.

PUF Sampling Rates for Any Place in the World!

May 10, 2019

The Research Translation Core released the first in a series of web-based applications designed to transfer ISRP research methods and data to researchers, regulators, government, the general public, and other stakeholder communities. It is a method for accurately predicting the sampling volume of passive air samplers deployed anywhere in the world!

This interface was completed as a results of the work done in Herkert et al. (2018). The interface is equipped to run for any dates between Jan. 1, 2010 and Apr. 30, 2018. The samples are collected from twenty-four sites deployed by the Global Atmospheric Passive Sampling (GAPS) network. The model provides information on environmental pollutants at any location around the world.

Isrp Assists in the Community Reporting of Air PCBs

February 05, 2018

The Iowa Superfund Research Program, the Boston University Superfund Program (BUSRP), and three community groups formed a partnership of five project leaders to measure the amount of airborne PCBs in the New Bedford Harbor area. The three community groups were the Toxics Action Center, Alternatives for Community and Environment (ACE), and the Hands Across the River Coalition (HARC).

ACE and HARC developed research questions related to New Bedford Harbor and shared these questions with BUSRP. BUSRP engaged researchers at the Iowa Superfund Research Program, who have a long history of studying lower molecular weight PCBs and their sources. HARC’s role was to recruit air monitor hosts interested in New Bedford Harbor environmental health concerns.

Two workshops were held with monitor hosts so that they could understand the data collected. Monitor hosts worked in pairs with assistance from the Toxic Actions Center and BUSRP to translate the data. The hosts became much more confident in interpreting the data and comparing them to data generated by the EPA. This outreach and cooperation model can be used for other communities impacted by environmental pollutants.

The complete article describing the results of their cooperation can be found in Environmental Science and Pollution Research.

New Study on PCBs in Schools

February 05, 2018

Isrp researchers Dr. Keri Hornbuckle and Dr. Peter Thorne were interviewed by numerous newspapers and National Public Radio after the release of their findings of polychlorinated biphenyls (PCBs) in schools in the journal Environmental Science and Technology.

The study showed that PCBs are present in older schools and that the source of the PCBs is most likely outdated building materials, such as window caulking and light ballasts.

The study, which collected indoor and outdoor air samples at six schools in Iowa and Indiana from 2012 to 2015, is the largest yet to examine airborne PCBs in schools. It shows that while the presence of PCBs can vary from school to school and even from classroom to classroom, children’s exposure rates are roughly the same in rural and urban areas.

It also shows that exposure to PCBs by inhalation may be equal to or higher than exposure through diet, a finding that surprised researchers. Besides PCBs, researchers looked for the first time at OH-PCBs, chemical compounds similar to PCBs, in schools. Although there is still much to learn about OH-PCBs and their potential health risks, some scientists believe they could be more toxic than PCBs.

Following publication of the article, representatives from the EPA and ATSDR and several community groups in the East Chicago area discussed the findings with staff.

Dr. Schnoor Honored at American Chemical Society Meeting

May 24, 2017


The University of Iowa Superfund Research Program Project 5 Leader Dr. Jerry Schnoor was honored at the American Chemical Society Annual Meeting(link is external) in San Francisco on April 2nd and April 3rd. Jerry was honored as having had a profound impact on our field, through leadership in environmental chemistry and modeling, shaping policy, and impacting our educational approaches to our most pressing environmental and health challenges. Jerry's contributions have been impactful in many areas of our field, including groundwater modeling and remediation, air pollution issues and climate change.

The topics that were covered in the two day Tribute to Jerry Schnoor sessions included, but were not limited to, Air modeling: Chemistry and Exposure; Environmental modeling, pollutant transport; Phytoremediation: Plant-mediated Chemistry; Nanoparticle environmental transport and fate.

In the above picture Dr. Schnoor(middle) is surrounded by many of the colleagues that honored him, including Dr. Heather Henry (third from right) from the NIEHS Superfund Research Program.

Engineering Students Learn About PCBs

May 22, 2017

On April 27, 2017, Dr. Rachel Marek from Project 4 gave a guest lecture at the Milwaukee School of Engineering in Prof. Anne Alexander's Fundamentals of Environmental Chemistry class, an elective of 24 juniors and seniors. She introduced students to PCBs and why we are concerned about their presence in schools. Students built molecules of PCB 11 and PCB 52, two PCBs that are prominent in school air due to paint and legacy Aroclors. They talked about partitioning coefficients and what that means for their volatilization.

Dr. Marek described the extensive field sampling campaign, lab methods, and quality control analysis for PCBs in school air. The students compared congener profiles of the school air with potential Aroclor and paint source profiles to determine the main identifiable source (specific Aroclor and/or pigment) of PCBs in that school. The students used historical Aroclor information to determine where in the school the Aroclors were likely present (light ballast, caulking, floor adhesive).