Plenary Speakers

Sunday August 20:

Persistent, bioaccumulative and toxic contaminants in marine mammals: a legacy concern for conservationists

Peter S. Ross

Director, Ocean Pollution Research Program, Coastal Ocean Research Institute

“Dr. Peter S. Ross, an internationally recognized scientist with over 25 years of experience in marine pollution research in government and academia, is serving as the Program’s founding director and senior scientist.”

The Stockholm Convention is a remarkable international treaty that was founded on good scientific research, concerns about health impacts in aquatic wildlife and on the safety of traditional seafoods for aboriginal communities, and the recognition that many persistent, bioaccumulative and toxic chemicals are travelling into remote regions of the world. Our work on marine mammals in Europe, the Arctic and the NE Pacific has shed light on the nature of food web bioaccumulation of POPs, and on the effects of PCBs on the endocrine and immune systems of different species. However, most troubling perhaps is our prediction that the Southern Resident Killer Whales frequenting the waters off Vancouver and Seattle will not be ‘safe’ from PCB-related health risks until the late 21st Century. This is one chemical among hundreds of thousands on the market. Such findings are highly relevant to conservationists dealing with real world threats to wildlife populations, but they also raise profound questions about the vulnerability of long-lived, high trophic level species, and about the effectiveness of chemical regulation and risk assessment paradigms. Simply put, short-term, lab-based toxicity testing with laboratory species fails to deliver the data needs of risk assessors, and we continue to conduct large-scale experiments in the natural world. A more precautionary approach to regulatory oversight would better capture such key considerations as trophic level, longevity, mobility and the relationship between endocrine disruption and the traditional measures of effects (growth, reproduction and mortality) before chemicals enter the marketplace.


Monday August 21:

Dioxin and the AHR: The Beginnings and no end in site,

Stephen Safe

Department of Veterinary Physiology and Physiology, Texas A&M University, College Station, TX 77843-4466

Otto Hutzinger – The Early Days

In the late 1960's, Otto Hutzinger was a newly hired Research Officer at the National Research Council (NRC) Regional Laboratory on the campus of Dalhousie University in Halifax, Nova Scotia. His interest in PCBs and Dioxins resulted from a conversation with Vlado Zitko, a scientist with the Fisheries Research Board in St. Andrews New Brunswick. Vlado indicated his concern regarding organochlorine environmental contaminants and suggested that environmental chemistry and impact of these compounds would be a "hot" area of research. I was also a Research Officer at NRC and Otto persuaded me to get involved in this new area of environmental research which would give us independence from our immediate supervisors and also be lots of fun. I reluctantly agreed, and from 1971-1974, we coauthored 35 refereed publications, at least 10 review articles, and two books, "The Chemistry of PCBs" (Hutzinger, Safe and Zitko) and "Mass Spectrometry of Pesticides and Pollutants" (Safe and Hutzinger) and founded a small company. Some of this early work described the first studies showing that PCBs could be photodegraded and metabolized (1-3), and these collaborative studies were continued after Otto was appointed Professor Environmental Chemistry at the University of Amsterdam in 1975 and I joined the University of Guelph in 1973. One of the lessons I learned from Otto was his attitude toward senior authorship and credit – he always favored his colleagues over himself.

After leaving NRC, Otto continued his studies on organohalogen pollutants and was the first to discover the formation and emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurants (PCDFs) from municipal waste incinerators. Otto was an original thinker and mentor to a generation of environmental scientists at the Universities of Amsterdam and Bayreuth, and he was continually organizing research conferences (starting with Dioxin 1 in Rome), editing journals (e.g. Chemosphere), and books (e.g. The Handbook of Environmental Chemistry). Otto was one of a kind and is greatly missed.

Dioxin and the Ah Receptor
The combination of several poisoning incidents due to occupational and accidental release of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and contaminated PCBs in Fukuoka (Yusho poisoning), Taiwan (Yucheng poisoning), and Seveso (TCDD) coupled with their widespread environmental contamination, stimulated scientific, regulatory and legal concerns about halogenated aromatics. All of these issues and their resolution were presented and discussed during the annual "Dioxin Symposia". Although some occupational exposures and the Seveso accident primarily involved a single toxicant, TCDD, other accidents and environmental exposures to persistent organic pollutants (POPs) involved TCDD and many other individual PCDD, PCDF and PCB congeners. The analytical approaches included development of high resolution separation and detection approach which are now routinely used to quantity POP congeners from multiple sources at the sub-parts-per-trillion level. Since human and other biota are exposed to complex mixtures of POPs, it was imperative to develop hazard and risk assessment paradigms that could quantitatively assess mixture-induced responses. Pioneering work by Dr. Alan Poland (4) showed that the mechanism of action of TCDD and structurally related PCBs, PCDDs and PCDFs involved initial binding to an intracellular protein designated as the aryl hydrocarbon receptor (AhR). This was later confirmed in AhR knockout mouse models where the characteristic AhR-mediated toxicities for TCDD and structurally related compounds were observed in wild-type but not AhR-knockout (AhRKO) mice. Thus, it was possible to develop a dioxin or toxic equivalents (TEQ) approach for risk assessment of TCDD- or dioxin-like compounds (DLCs), where

TEQ = ∑[(DLCi)  (RPi)]

the dioxin equivalents is equal to the summation of the individual concentrations of the DLC (DLCi) times their relative potency (RPi) compared to TCDD (arbritarily set at 1.0) (5). This initial approach has been continually refined and modified as new data become available and has been used extensively by regulatory agencies to reduce emissions and environmental/human exposures to DLCs. The TEQ approach was invaluable for estimating the potential toxicity of an important sub-class of POPs (i.e. DLCs); however, evaluation of the potential adverse effects of non-DLCs is still a major regulatory problem

The AhR and Its Ligands: Health and Therapy
Although AhRKO mice are viable and reproduce, initial studies by Bradfield and others have identified an increasing number of defects in these animals, demonstrating that the receptor may play a role in organ/tissue homeostasis (6,7). For example, AhR-deficient mice exhibit a decreased liver size but only during development due to defects in closure of the ductus venosus. AhRKO mice have difficulty in maintaining pregnancy, they have an increased susceptibility to infection indicating a role for the AhR in the immune system function and the AhR also plays a role in stem cell development. Moreover, there is extensive evidence from transgenic animal studies that the AhR plays a critical role in intestinal health via interactions with microbiota-derived AhR metabolites and the AhR exhibits tissue-specific promotion or protection from cancer (8). Ongoing research continues to add to the growing list of AhR functions in animal models and to a lesser extent in humans and this makes the AhR an ideal target for drug development.

Receptors such as the estrogen receptor are among the most well developed targets for drug development since receptor-mediated adverse effects can be treated with receptor antagonists and receptor-mediated health benefits can be enhanced by receptor agonists. Although AhR-interactions with TCDD and related compounds lead to well characterized toxicities, the AhR also binds several endogenous biochemicals, health promoting phytochemicals, AhR-active pharmaceuticals, multiple microbiota-derived AhR ligands and synthetic AhR antagonists (9). These compounds are selective AhR modulators (SAhRMs) that exhibit tissue-specific AhR agonist or antagonist activities and can be exploited for treatment of multiple diseases including cancer, inflammatory bowel disease, immune and autoimmune diseases and expansion of stem cells. Development of AhR-active drugs has been a "cautionary tale" due to concerns of "dioxin-like" side effects; however, some of the current AhR-based drugs in clinical trials include Laquinimod for treatment of multiple sclerosis and StemReginin 1 (SR1), an AhR antagonist use for production of hemapoietic stem cells.


Tuesday August 22:

Environmental Forensics of Persistent Organics Pollutants

Gwen O’Sullivan


Dr Gwen O’Sullivan is an Assistant Professor of Environmental Science. Dr O’Sullivan earned a B.Sc. in Environmental Science from the University of Limerick and a Ph.D. in Environmental Chemistry from Queen’s University of Belfast. Over the course of her career, in industry, consultancy and academia, Dr. O’Sullivan has developed technical expertise in the areas of environmental chemistry, environmental forensics, air quality and contaminated land and groundwater. She has worked on numerous research and industrial projects including the development of technologies and remedial actions, plans for the treatment of contaminated sites. Dr O’Sullivan has also designed and managed environmental forensic investigations involving compounds of concerns including drilling fluids, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenlys, polychlorinated dibenso-p-dioxins and dibenzofurans, methane and nitrates. She has also authored numerous scientific articles, edited books series and successfully competed for research grants both nationally and internationally.

Environmental forensics is a fast growing field of science which incorporates interdisciplinary knowledge to assess the source, age and timing of release of a contaminant(s). Environmental forensic investigations are methodical assessments of multiple lines of information, which may be used in litigation, to allocate responsibility for contamination. Environmental forensic studies can range in complexity; the simplest form may involve the identification of a source of contamination based on the presence or absence of chemical markers. More complex cases may involve mixed sources and environmental weathering which require advanced statistical interpretation to detangle distinctive signatures. Environmental forensics not only involves litigious matters but may also be applied to publicly disputed issues to support a particular claim or a position.

In toxicological studies it is important to separate the World Health Organisation 12 dioxin like polychlorinated biphenyls (WHO 12). However in environmental forensics studies a greater number of congeners are often needed to be separated to identify processes such as microbial degradation, volatilisation, and biotransformation in humans. Advancements in analytical techniques, including single and multidimensional time of flight mass spectrometry, has allowed for such congener profile development at trace levels. The amount of data generated from such analyses is vast and can require advanced multivariate statistical analysis techniques to discern patterns/source, differentiate background influences, and apportion contributions/liability.

This presentation will examine the development of environmental litigation including key treaties, statutes, regulations and case law pertaining to the control of persistent organic pollutants. A review of the interdisciplinary requirements of environmental forensic investigations including legal sampling techniques, analytical advancements, fate and transport, and statistical presentation in court will be provided. The presentation will conclude with discussions on advancements, limitations and recommendations for the development of the field of Environmental Forensics.


Wednesday August 23:

Science and Policy of POPs through Passive Air Sampling

Tom Harner

Dr. Tom Harner leads a research group in the Hazardous Air Pollutants (HAPs) laboratory of the Atmospheric Processes Research Section of Environment and Climate Change Canada. He investigates the atmospheric transport and fate of persistent organic pollutants (POPs) and emerging chemicals to inform domestic and international chemicals risk assessment, risk management and to advance science. Since, 2004, Tom has actively contributed to international assessments on POPs under the Stockholm Convention on Persistent Organic Pollutants (POPs) as well as the POPs Protocol of the Convention on Long-Range Transboundary Air Pollution (CLRTAP). Since 2007, he has served as the Canadian representative on the Global Coordination Group for the global monitoring plan of the Stockholm Convention. Tom and his group devise new passive sampling tools and approaches and apply them to research and monitoring. His group operates two long term programs - the GAPS (Global Atmospheric Passive Sampling) Network and a passive sampling network in the Athabasca Oil sands region.

Since its inception in 2000, the polyurethane foam (PUF) disk passive air sampler has greatly advanced our understanding of the occurrence, transport and fate of persistent organic pollutants (POPs) and emerging chemicals. The ability to collect spatial information on both gas-phase and particle-associated POPs in a simple and cost-effective way has led to vast datasets for improving our understanding of regional and global-scale transport of POPs through models. This integration of passive air sampling data with models and emissions, coupled with the adoption of the PUF disk sampler by numerous research programs around the world, has led to the promulgation of the sampler under the Global Monitoring Plan (GMP) of the Stockholm Convention for addressing policy needs related to chemical risk assessment and risk management. The Global Atmospheric Passive Sampling (GAPS) network, which has been operating since 2005 at more than 50 sites on all seven continents, provides a unique global-scale picture on POPs. This plenary presentation will be a historical perspective of the PUF disk passive air sampler over the last 17 years. It will touch on the motivations for this technology, the early adoption that led to widespread use today, and the intersection of the science with policy needs at the international scale under the Stockholm Convention on POPs. We will also look to the future to some novel and exciting applications and approaches of passive air sampling.


Thursday August 24:

The role of environmental chemicals in obesity

Juliette Legler

“Juliette Legler is Professor of Toxicology and Environmental Health at the College of Health and Life Sciences, Brunel University London. She is also leader of the Environment and Health Theme, a multidisciplinary group of about 60 researchers within Brunel University’s Institute for Environment, Health and Societies. Prior to joining Brunel University London in January 2016, she was employed for over 14 years at the Institute for Environmental Studies, VU University Amsterdam, where she was Deputy Head of the Department of Chemistry and Biology. From 2014-2015 she served as Director of the SENSE Research School for Socio-Economic and Natural Sciences of the Environment, a joint venture of the environmental research institutes of ten Dutch universities. Voted the VU’s Faculty of Earth and Life Sciences Teacher of the Year in 2012, she has taught environmental toxicology at the BSc and MSc level at the VU and coordinated an MSc program in Environmental Chemistry and Toxicology. Her research focusses on the molecular mechanisms of toxicity of chemicals and the effects of chemical exposure on humans and wildlife. An author of about 100 scientific articles and book chapters, she is particularly interested in understanding the role of epigenetics in the long term health impacts of early life exposure to environmental chemicals. Prof. Legler is a European registered toxicologist and was elected Vice President of the Netherlands Society of Toxicology in June 2015.”

The global incidence of obesity is one of the most serious public health challenges of our time. It is increasingly clear that environmental factors early in development, such as exposure to chemicals, play a role in the etiology of obesity. In recent years I have used an integrated toxicological and epidemiological approach to research the role of environmental chemicals in obesity. My research suggests that prenatal exposure to chemicals affects processes involved in obesity development, including increased differentiation of adipocytes, altered energy metabolism, and elevated weight in childhood. Current research in my lab is focused on unravelling the epigenetic mechanisms by which chemicals may perturb metabolic pathways and adipogenesis using in vitro and zebrafish models. I expect that by discovering novel gene regulatory mechanisms in obesity that can be disrupted by chemical exposure, novel risk factors involved in the etiology of obesity can be identified in order that preventative strategies be introduced to reduce obesity and the related drain on health care systems worldwide.


Friday August 25:

Contamination and human exposure to micropollutants including dioxin-related compounds in informal recycling sites for e-waste and end-of-life vehicles

Shin Takahashi

Dr. Shin Takahashi is currently Associate Professor of Ehime University, Center of Advanced Technology for the Environment, Graduate School of Agriculture. He was a former researcher of Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies (NIES). His Ph.D. is in Environmental Chemistry obtained from Ehime University, Japan. His current fields of interest are environmental chemistry and ecotoxicology of persistent toxic substances including POPs, dioxin-related compounds, organometallics and endocrine-disrupting chemicals. He is interested in elucidating the global contamination and fate of persistent toxic substances and to assess their potential risk and emission behavior during material cycling processes. He is a member of the advisory committee for the waste management policy of the Ministry of Environment, Japan, and a member of the editorial board of the Japan Society of Environmental Chemistry and a director of Chugoku-Shikoku affiliate of the Japan Society of Material Cycles and Waste Management. Recently, he bought a very old (and thus very cheap) Mercedes-Benz 300SD, and drive it by 100% biodiesel fuel which is recycled from waste edible oil collected in his town as a 3R action in local society.

Effective management of electronic waste (e-waste) has become a major issue of the modern world from both economic and environmental perspectives. Recently, end-of-life vehicles (ELV) has also become a matter of increasing concern because of their trade and management for reuse and recycling. E-waste and ELV contain valuable and reusable/recycable components and material but requires appropriate handling and recycling because of the high content of many hazardous substances, including toxic heavy metals as well as polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs) and other toxic additives. However, informal recycling for e-waste/ELV using primitive techniques, which have been noted in developing or newly industrialized countires, results in environmental release of not only hazardous substances contained in these ‘modern’ wastes but also toxic secondary contaminants, including complex mixtures of dioxin-related compounds (DRCs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and their brominated and mixed brominated/chlorinated analogues (PBDD/Fs and PXDD/Fs), as well as chlorinated/brominated polyaromatic hydrocarbons (Cl-/Br-PAHs). Assessing the environmental and human health impacts related to these pollutants from informal waste recycling activities is challenging due to the large number of compounds and the big data gap regarding their toxic potency. For the last several years, we conducted environmental and human monitoring in informal recycling sites for e-waste and ELV in northern Vietnam and Ghana, to evaluate environmental release of micropollutants including various DRCs and to assess their human health risk. I will present some details on the occurrence and contamination status of micropollutants in the e-waste/ELV recycling sites in northern Vietnam and discuss toxic identification and evaluation in view of dioxin-like toxicities using the dioxin receptor-CALUX in vitro bioassay. In addition, our recent results on targeted and non-targeted analysis for DRCs and Cl-/Br-PAHs in soil from an e-waste burning site in Ghana will be reviewed.