The Science of Dioxin

January 25, 2017 | Commercial Litigation | Complex Torts & Product Liability

Researchers Say They Have Mapped PHCZs in the Great Lakes

Researchers from the School of Public Health, the Department of Civil and Materials Engineering, and the Department of Earth and Environmental Sciences at the University of Illinois at Chicago and from the Department of Veterinary Biomedical Sciences and Toxicology Centre at the University of Saskatchewan have published a paper mapping the presence of polyhalogenated carbazoles (“PHCZs”) in the Great Lakes.


The paper, entitled, “Spatial and Temporal Trends of Polyhalogenated Carbazoles in Sediments of Upper Great Lakes: Insights into Their Origin,” was authored by Jiehong Guo, Zhuona Li, Prabha Ranasinghe, Solidea Bonina, Soheil Hosseini, Margaret B. Corcoran, Colin Smalley, Karl J. Rockne, Neil C. Sturchio, John P. Giesy, and An Li.

It was published online in Environmental Science and Technology.

The Study

The paper noted that PHCZs “have been increasingly detected in the environment,” that they resemble polyhalogenated dibenzo-p-dioxins and dibenzofurans (“PCDD / Fs”) in chemical structure, and that they have received “little attention” since their first detection in the environment in the 1980s.

To conduct their study, the researchers said, they took sediment samples from Lakes Michigan, Superior, and Huron and analyzed a total of 26 PHCZs.

They concluded that the total accumulation of PHCZs in the sediments of the upper Great Lakes was more than 3,000 metric tons – “orders of magnitude greater” than those of polychlorinated biphenyls (“PCBs”) and decabromodiphenyl ether (“BDE209”).

According to the paper, certain PHCZs “were more abundant in sediment of Lake Michigan deposited before 1900 than those deposited more recently, implying a natural origin.”

The paper added that some “emerging” PHCZs “have been increasingly deposited into the sediment in recent decades,” and concluded that they “deserve further environmental monitoring and research.”

* * *

Paper Examines Dioxin in Elbe River Basin

A paper entitled, “Dioxin in the Elbe river basin: policy and science under the water framework directive 2000-2015 and toward 2021,” has been published in Environmental Sciences Europe.


The paper, by Ulrich Förstner, Henner Hollert, Markus Brinkmann, Kathrin Eichbaum, Roland Weber, and Wim Salomons, stated that it was a “critical review of the last 25 years of dioxin policy in the Elbe river catchment.” Elbe River is one of the major rivers of Central Europe, and its catchment area is the fourth largest in Europe.

Among other things, the authors wrote that, with respect to dioxin, “large-scale stabilization applying activated carbon additions is particularly promising” and that goals of the European Water Framework Directive (“WFD”) to reach a “good chemical status” were not met in many catchment areas “because substances such as mercury do and others probably will (PCDD/Fs and dl-PCB) exceed biota-EQS values catchment area-wide.”

* * *

Paper Claims Polar Bears Threatened by Arctic POPs

A research paper published in Environmental Toxicology and Chemistry has suggested that so-called persistent organic pollutants (POPs), including polychlorinated biphenyls (“PCBs”) and dioxins, in the Arctic food chain pose a very low risk for seals, but a risk two orders of magnitude higher for adult polar bears and three orders of magnitude above the threshold for bear cubs fed with POPs-containing milk.


The paper, entitled “Risk of POP Mixtures on the Arctic Food Chain,” is by Sara Villa, Sonia Migliorati, Gianna Serafina Monti, Ivan Holoubek, and Marco Vighi, of the Department of Earth and Environmental Sciences and the Department of Economics, Management, and Statistics at the University of Milano Bicocca in Milano, Italy, as well as at the Research Centre for Toxic Compounds in the Environment (“RECETOX”) at Masaryk University in Brno, Czech Republic, and the Madrid Institute for Advanced Studies in Water (“IMDEA Water”) in Madrid, Spain.

As explained in the paper, POPs are chemicals that “remain intact in the environment for long periods, travel long distances, accumulate in living organisms, and are toxic to humans and wildlife.” They are capable of transport “via air, water, migratory species, and technical matrices such as products and wastes; thus, they become ubiquitous in the environment.”

Paper’s Conclusions

The paper conceded that its results were “based on a series of assumptions and approximations” that, it said, “were necessary because of the lack of complete and detailed knowledge of many aspects of the process of risk characterization.” In particular, it said, the “complexity of the toxicological modes of action of the chemicals considered” led the authors to “a worst-case characterization and to a possible overestimation of the actual risk.”

It concluded that changes in the composition of POPs highlighted “the fact that more attention must be paid to emerging contaminants” and that there should be further mitigation measures taken “for legacy as well as for additional, not yet controlled, POPs,” with their appearance in the environment something that only may be “solved over generations.”

For further information, please contact James V. Aiosa, Paul V. Majkowski, Lawrence S. Han, or your regular Rivkin Radler attorney.

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