CITE seminar series

CITE - Chemicals In the Environment - is a research topic within the Helmholtz programm oriented funding. CITE addresses multiple aspects of the impact of chemicals in the environment. The seminar series (irregular) with invited external speakers aims to reflect these different aspects.

Scheduled seminars

Date: Thursday, November 20th, 10:30am, building 6.0 room 111

Presenter: Samuel Arey (EPFL Lausanne)

Title: “Analysing reactive molecules in aquatic systems using quantum chemistry”

Host: Dr. Kai-Uwe Goss


Aqueous reactive molecules are important agents of chemical transformation in both natural and engineered water systems. However these species are often challenging to study by experiment. Computational quantum chemistry models allow us to explore their structures, properties, energies, and reactivities. In this talk I will discuss results from several in silico studies on aqueous reactive molecules. Focus will be placed on recent efforts to describe chemical equilibria, transformation mechanisms, and one-electron oxidation processes of environmentally relevant aquatic species, using high quality quantum chemistry protocols.

Date: Tuesday, November 25th, 02:00pm, building 6.0 room 111

Presenter: Frank Wania (University of Toronto)

Title: “Simulating differences in exposure to PCBs between generations, sub-populations, and individuals”

Host: Dr. Kai-Uwe Goss


By integrating models of environmental fate and food chain bioaccumulation we now have the capability to mechanistically describe a PCB’s journey from initial release into the physical environment to its accumulation in top predators, including humans. A particularly important feature of the combined model is its dynamic nature, which allows for time-variant simulations covering periods of multiple decades. The integrated model can be used to further our understanding of differences in PCBs exposure between different human generations, between human sub-populations that differ in terms of diet and living environment, or between different wildlife species. The model can also be used to assess the effectiveness of policy options, e.g. the issuing of dietary advisories to reduce infant exposure to PCBs. By combining the model with human biomonitoring efforts, such as NHANES, we currently seek to simulate PCB exposure of individuals. Information on age, year of birth, gender, diet, reproductive behavior (number of children, age at birth, breastfeeding habits), and body mass index obtained through the questionnaires accompanying biomonitoring studies is translated into individualized model input parameters, allowing for a prediction of each study participant’s longitudinal PCB exposure. This not only allows for the identification and quantification of the factors that contribute to the differences in human exposure to PCBs, but could also open the door to predicting exposure during time periods of particular exposure sensitivity earlier in life.

Date: Tuesday, November 25th, 03:00pm, building 6.0 room 111  

Presenter: Dr. April Gu  (Northeastern University Boston)

Host: Prof. Dr. Beate Escher

Title: "Explore Quantitative Toxicogenomics For Toxicity Assessment and Water Quality Monitoring"

Abstract: The contaminants of emerging concern (CECs), such as endocrine disrupting compounds (EDCs), pharmaceuticals, personal care products (PPCPs) and nanomaterials, are anticipated to greatly increase the demands for their toxicity, ecological effects and risk assessments. Current whole animal/organism exposures-based methods used for regulatory decision-making in ecotoxicology are resource and time-intensive and, they provide little information on toxicity mode of action (MOA) and cellular level sub-lethal impact. Alternative and/or complimentary toxicity screening methods, which are less costly, yet with informative endpoints are needed. Recently, we have explored the application of a toxicogenomics approach for toxicity assessment and screening of CECs, using a comprehensive GFP-infused bioluminescent whole cell array. Compared with traditionally microarray technology, this method is simpler and faster, and therefore is feasible for screening a large number of chemicals. Furthermore, it provides multi-dimensional transcriptional level effect information, by adding a temporal dimension to the gene expression data, and therefore can more accurately reflect the chemical-induced cell responses that are time-dependent. We demonstrated that toxicogenomic data could also be used to potentially identify and classify compounds with similar MOAs (mode of action) while gaining diagnostic insights into the causal agents. One of the main challenges in applying toxicogenomics for environmental monitoring is the lack of a quantitative method to convert the rich toxicogenomic information into a readily usable and transferable format that can potentially link to regulation endpoints and be incorporated into ecological risk assessment and regulatory framework. We proposed a new transcriptional effect level index (TELI) that exhibited a dose-response relationship and allowed for linking (“phenotype anchoring”) the transcriptional level effects to conventional toxicity endpoints. Cross-species comparison and extrapolation is another key aspect related to predictive and mechanistic toxicity assessment to overcome the limitation of data generation ability. We have compared genotoxicity across three different species for variety of compounds and demonstrated the possibility of cross-species extrapolation with stress-response pathway ensemble based toxicity assessment.

Short Bio: Dr. Gu is an associate professor in Civil and Environmental Engineering Department, faculty and track leader for Interdisciplinary Bioengineering Program within the College of Engineering and affiliated faculty for Biotechnology Program with Bouve College of Health Sciences at Northeastern University in Boston. She obtained her B.S. in Environmental Engineering and Science from Tsinghua University in Beijing, China and a Ph.D. in Civil and Environmental Engineering, jointly in Microbiology, from the University of Washington in Seattle. Her expertise and area of research interest include application of biotechnology for water and wastewater treatment, water quality monitoring and toxicity assessment, biosensors, biological wastewater treatment processes and modeling, microbial ecology, bioavailability of nutrients in aquatic systems and bioremediation. She is an Editorial Board member for Water Environmental Research Journal, Frontiers of Toxicogenomics, and Associate Editor for Water Science And Technology Journal. She serves on a number of international and national committees for IWA, WEF and AWWA. She has received a number of national awards including NSF CAREER award in 2009, SETAC Global Best Student Paper Award, ACS Outstanding Presentation Merit Award and Søren Buus Outstanding Research Award from Northeastern University. She was invited speaker for Gordon Conference-Environmental Nanotechnology 2013, and Gordon Conference – Water Science in 2012.

Date: Wednesday, November 26th 12:30pm, building 6.0 room 111

Presenter: Xiaowei Zhang, PhD (Nanjing University, China)

Title: “Development of Next Generation Technologies for Environmental Monitoring and Ecological Risk Assessment”

Host: Dr. Werner Brack


Prof Zhang's research interests include ecotoxicology of environment pollutants and chemical safety research. The current research focuses on mechanistic toxicology of emerging chemicals and environmental genomics, in particular, the development of Next Generation Sequence (NGS) technology based high throughput assays for chemical toxicity assessment and ecological monitoring of biodiversity. His research involves both laboratory experiments and field studies (e.g. biomonitoring using environmental DNA)

Date: Wednesday, November 26th 03:00pm, building 1.0 lecture hall

Presenter: David Werner (Newcastle University)

Title:Sorption and Biodegradation: A complicated relationship

Host: Dr. Lukas Wick & Dr. Beate Escher


Sorption and biodegradation are fundamental processes contributing to the attenuation of organic pollutants in soils and sediments. While sorption reduces the mobility and often also toxicity of organic pollutants, it can hinder the pollutant biodegradation and enhance persistence. Many laboratory studies have demonstrated that sorption reduces the bioavailability of pollutants and hence the pollutant transformation by microorganisms. This presentation, however, will argue that the persistence of organic pollutants in the natural environment is often due to biological limitations in which case sorption can help with the pollutant biodegradation along a source-receptor pathway. Furthermore, extracellular electron transfer through the matrix of carbonaceous sorbents with high aromaticity ("black carbon") will be discussed as an interesting new mechanism by which sorption may assist with the dechlorination of persistent pollutants like DDT in anaerobic soils and sediments. Consideration of such mechanisms is of great importance for the design and monitoring of in-situ soil and sediment remediation strategies which use strong sorbents like activated carbon or biochar.

Date: Tuesday, December 2nd, 02:00pm, KUBUS Hall1A

Presenter: Kristopher McNeill (ETH Zürich)

Title: “Environmental Photochemistry: From Triclosan to Dioxins”

Host: Prof. Dr. Thorsten Reemtsma


Triclosan is an antibacterial compound widely used in consumer products, including liquid soaps and toothpaste. Accordingly, triclosan has been found in surface waters that receive wastewater all over the world. Prior work has identified photochemical degradation as a major loss process for triclosan in surface waters, which leads to short persistence of triclosan in such systems. This seemingly happy circumstance is accompanied by the worrisome discovery that triclosan’s transformation products include chlorinated phenol, chlorinated dioxin and dihydroxy-PCB products. More recent work has revealed that the water treatment strategies greatly influence the prevalence of more toxic dioxin congeners in environmental systems. This presentation will summarize the current state of knowledge and present unpublished work on the photochemistry of triclosan.

Date: Wednesday, December 3rd, 01:00pm, KUBUS Hall1CD

Presenter: Katrin Wendt-Potthoff (SEEFO)

Title: “The plastisphere – microplastics in aquatic ecosystems”

Host: Dr. Lukas Wick & Prof. Dr. Rolf Altenburger


Plastic debris in the oceans is a well-known and publicly discussed environmental problem. However, despite the fact that up to 80% of marine plastic pollution originates in the terrestrial environment, transport and ecosystem effects of plastics in limnic systems are not well studied. The presentation introduces the challenges of microplastic quantification in the environment, summarizes present knowledge on plastics in rivers and lakes, and highlights approaches to study colonization and degradation of microplastics by microbes. Based on this, knowledge gaps and research needs can be discussed.

Date: Monday, December 8th, 10:30am, KUBUS Hall1A

Presenter: Kathrin Fenner (EAWAG)

Title: “Towards a more accurate prediction of the biotransformation of chemical contaminants – What we can learn from combining data mining, analytical chemistry and molecular biology tools”

Host: Prof. Dr. Hauke Harms


Dr. Stefan Scholz
Department of Bioanalytical Ecotoxicology, UFZ
Tel.: 0341 235 1080