Program

During the early years of my career, I focused on the speciation of mercury and arsenic in water, sediment and biota using hyphenated methods. Shortly after Lancaster developed the DGT technique, we adopted it in our laboratory, because the advantages we saw were manifold: (1) instead of repeated grab sampling over a period of time, we could realize integrated, in situ sampling over that period; (2) the detection limits for certain elements, especially in pristine systems, are too high. With the DGT, which is a preconcentration technique, that problem can be overcome; (3) with the classical slice and squeeze technique one can obtain vertical element profiles in sediment cores but the resolution is weak. The DGT technique allows to greatly improve that resolution and even move from 1-D profiles to 2-D images; (4) speciation of elements such as Hg or As can be performed by an appropriate choice of binding resin. We thus applied the DGT in a variety of aquatic systems to study the biogeochemical cycles of many chemical compounds. Our actual focus is on the determination and behavior of microorganic pollutants (in polluted environments) and micronutrients (in high nutrient low chlorophyl environments) using new DGT types and models.

Josep Galceran is Full Professor in Physical Chemistry at the Universitat de Lleida (Catalonia, Spain). He has been working with analytical techniques to measure speciation and availability since 1994, with special emphasis on the interpretation of the analytical outputs through modelling. His contributions include the proposition of new concepts (such as the “lability degree” or the interpretation of cDGT), new formulas (such as those allowing to extract information from the ratio of accumulation between the back and front binding layers in DGT devices), new simulations (such as the diffusion, adsorption and complexation of metal ions in soils for DGT deployments), new interpretations of experimental results (DGT devices attached to seagliders or novel binding materials for iodide or uranium), etc. He has co-authored one chapter in the DGT book edited by W. Davison and more than 25 articles on DGT. He keeps many collaborations with international laboratories.

Martine Leermakers is an Analytical Chemist and Professor at the Vrije Universiteit Brussel (VUB), Belgium. Her research interests include the development of analytical techniques for trace metals, organometals, metalloids and radionuclides as well as the study of the geochemical cycling of these elements in environmental compartments as well as human biomonitoring of trace elements and  the impact on human health. In the last ten years she has been working on the development of DGT passive sampling techniques for in situ trace metal speciation DGT for different metals and radio-isotopes (especially uranium and radium) and the application in mining and post-mining environments. The DGT technique has, for example,  enabled the research team to get more insight in the speciation of uranium, on the nature of the colloidal transport of U an Ra as well as on the bioaccumulation of U in chironomid larvae.

Dr. Chao Han is an associate professor at Nanjing Institute of Geography and Limnology, Chinese Academy of Science (CAS). He finished his MSC and PhD from Nanjing University. He is currently devoting himself to the development and application of chemical imaging technologies such as diffusive gradients in thin films (DGT), planar optode (PO) and zymography, etc., for in situ and high-resolution investigations into relevant biogeochemical processes at the sediment and water interfaces. He reported on the first combination of DGT and PO into a hybrid sensor and thus successfully realized the co-measurements of nutrients/metals and dissolved oxygen based on a single sensing film. Recently, based on DGT methods, he began to explore the spatial heterogeneity of labile biogenic elements (phosphorus, nitrogen, sulfur and metals) and their transportation on macro-and micro-scale levels in dozens of important lakes and rivers in China, in a bid to better understand the endogenous pollution process and design pollution/nutrient management strategies in water ecosystems. 

Dr Paul N. Williams is a fellow of the Institute for Global Food Security, Director of Queen’s University Belfast’s Agricultural Technology Degree, and Senior Lecturer in Soil & Environmental Biogeochemistry. Paul’s research interests centre on environmental/elemental metrology, understanding plant-soil interactions and improved soil management.  With over twenty years of experience investigating the widespread issue of arsenic and cadmium contamination in rice, he has followed this topic from the grain down into the soil. It is in this latter aspect, especially, that Paul has actively used DGT/DET for trace-element speciation, predicting bioavailability, modelling and high-resolution (sub-mm) 2D imaging. Using a range of other complementary methods such as multi-element chromatography (IC-ICP-MS), laser-based analytical measurement (LA-ICP-MS), optical sensors (planar optodes), in-situ UV/vis spectrometry and XRF analysis, his work has taken him to mining impacted sites in China, the peat swamp forests of Malaysia, uranium mine restoration projects in Brazil, and onto artisanal gold mining investigations in the rainforests of Guyana. In addition to a holding a senior editorial role in the Springer-Nature journal Exposure & Health, Paul sits on the editorial advisory board for the ACS journal ES&T and has held an editorial board position with Environmental Pollution for >15 years. 

Maria Jesus Belzunce Segarra, PhD in Chemistry, is a Senior Research Scientist working in the Marine Research Division at AZTI (member of the Basque Research and Technology Alliance), sited in the Basque Country (Spain). She has more than 20 years of research experience covering water and sediment quality assessment in estuaries and marine environment. Her main research interests include establishing relationships between contaminants and observed biological effects, and the application of novel assessment tools. During the last years she focussed her interest in applying passive sampling techniques, specially DGTs, for the chemical assessment of estuarine and marine waters. She applies this research through a wide range of regional, national and international projects.