Senior Team Members
Dr. Abdul Mossa
Postdoctoral researcher
Research interests
I am a soil scientist with a broad interest and training in soil geochemistry. The aim of my work is to determine the geochemical factors that control the dynamics of trace elements and their bioavailability in soils using a combination of modelling and experimental studies, including the use of enriched stable isotopes as tracers. My PhD research aimed to assess the impact of the suite of trace metal loads from biosolids application on plant and soil microbial communities. The study has important implications for the use of organic wastes in agricultural systems in terms of land management for silage or forage crops. During my previous postdoctoral positions, my research aimed to develop pathways to alleviate micronutrient deficiencies in the human diet by establishing a direct link between soil properties and the availability of trace elements to crops consumed by humans and livestock. During this time I have developed experimental approaches for the analysis of zinc, selenium, silicon, sulphur and iodine in soil, using isotopic labelling techniques and the application of predictive geochemical modelling to estimate the 'free ion activity' of trace metals - the main driver for plant uptake of some micronutrients.
I am currently working on a project that aims to determine selenium speciation in soil samples from Malawi. The main objective of the project is to combine existing data (obtained from the GeoNutrition project during my previous employment) on the spatial variation of selenium concentration in soils and crops with new experimental and modelling studies to identify the geochemical mechanisms in soils responsible for controlling the provision of dietary selenium, which is essential for human and animal health, thus contributing to efforts to eradicate 'hidden hunger'.
Finally, I have demonstrable experience and aptitude in R programming and data analysis and interpretation. The use of statistics (e.g., multiple linear regression, logistic regression and linear mixed models) and the development of mechanistic modelling has been central to my research.
Technical and analytical expertise
- Field sampling: Soil and plant
- Major & trace elements quantification: ICP-MS
- Statistical and data analysis: Machine learning, multivariate analysis, spatial statistics
- Programming: R and Python
Education and former positions
Postdoctoral Researcher (2015 – 2022)
Research Fellow / Technical Specialist
University of Nottingham, School of Biosciences, United Kingdom.
Research topic: Geo-nutrients – Tackling micronutrient deficiencies, also known as 'hidden hunger', by improving our understanding of soil factors that influence the nutritional value of our food. Main locations were Ethiopia and Malawi.
PhD in Environmental Science (2013 - 2017)
University of Nottingham/ School of Bioscience, United Kingdom.
Thesis title: The Impact of Long Term Biosolid Application on Soil Health
Thesis advisors: Scott Young, Neil Crout
Research Associate (2005 – 2013)
General Commission for Scientific Research, Syria
Research topic: effect of organic and inorganic fertilizers on the accumulation of heavy metals in soil.
MSc in Soil Science (2007-2009)
Damascus University, Syria.
Taught MSc in Soil Reclamation (2005)
Damascus University, Syria.
BSc in Agricultural Engineering (1999-2004)
Damascus University, Syria.
Dr. Athena Nghiem
Postdoc
Research interests
I am a geochemist with broad interests and training in hydrology, mineralogy, and statistics. The general questions my research investigates include (i) how do trace elements and geogenic contaminants threaten essential resources, such as water and air, and (ii) how can we improve representations of these processes and their environmental variability. I use data science methods to strengthen traditional laboratory, field, and process-based modeling approaches. My past research has focused on quantifying redox processes in Earth’s subsurface, such as the naturally-occurring release of arsenic into groundwater. Next, I am interested in investigating the redistribution of trace elements and their exchange between different reservoirs under anthropogenic and climatic impacts.
Technical and analytical expertise
- Solid-phase analyses: X-ray absorption spectroscopy at synchrotron facilities, XRF
- Water analyses: ICP-MS, TOC, IC
- Field sampling: groundwater, sediment cores
- Modeling: Reactive transport modeling, PHREEQC, Parameter Estimation and Uncertainty Analysis (PEST)
- Statistical analyses: Machine learning, R
Education and former positions
PhD in Earth and Environmental Sciences (2016-2021)
Columbia University & Lamont-Doherty Earth Observatory
National Science Foundation Graduate Research Fellowship (United States)
Thesis title: Data-driven approaches to linking hydrology, mineralogy, and biogeochemistry of groundwater arsenic contamination from grain to basin scale
Thesis Advisor: Benjamin Bostick
MPhil in Earth and Environmental Sciences (2016-2020)
Columbia University & Lamont-Doherty Earth Observatory
MA in Earth and Environmental Sciences (2016-2018)
Columbia University & Lamont-Doherty Earth Observatory
BA in Geophysics, and in Statistics (2016)
University of California, Berkeley
Thesis title: Particulate Composition and Subsurface Dynamics at Eel River Critical Zone Observatory
Dr. Andrea Stenke
Senior Scientist/Scientific Programmer
Research interests
I am a meteorologist by training and specialized in the development and application of numerical models of various kinds, from simplified box models to complex Earth-System-models. My previous research projects were focused on atmospheric chemistry, in particular on ozone, methane and water vapor as well as sulfate aerosols, and their interactions with climate. In my current position I will extend my modelling work to biogeochemical cycles of trace elements in different environmental compartments. My goal is to use process-oriented numerical models on different scales and machine learning techniques in combination with available measurements of trace elements, their speciation and further environmental parameters to better understand the processes driving the availability of trace elements to organisms, and how they change in a changing climate.
Technical and analytical expertise
- Numerical modelling: box models, chemistry-transport models, Earth-System-models
- Sensitivity and uncertainty analysis using statistical emulation and surrogate models
- Statistics and data analysis: Time series analysis, Bayesian methods, multivariate techniques
- Programming: Fortran, R, Matlab, Python
Education and former positions
Diploma of Advanced Studies in Applied Statistics (2021)
ETH Zurich, Switzerland.
Thesis title: Time series regression analysis of lower stratospheric ozone in southern mid-latitudes
Thesis advisor: Marcel Dettling
Postdoc / Senior Assistant (2009 – 2021)
Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland.
Research topic: Lead of the chemistry-climate modelling activities with SOCOLv3; research focus: atmospheric methane trends, solar impacts on atmospheric ozone, sulfate aerosols, atmospheric selenium cycle.
Postdoc (2006 – 2009)
Institute for Atmospheric Physics, DLR Oberpfaffenhofen, Germany.
Research topic: Lagrangian methods for tracer advection and dynamical cores in chemistry-climate models.
PhD in Meteorology (2002 - 2006)
University of Munich / Institute for Atmospheric Physics DLR Oberpfaffenhofen, Germany.
Thesis title: Stratospheric water vapor in a coupled chemistry-climate model: Simulation, trends and impact on ozone chemistry.
Thesis advisors: Volker Grewe, Robert Sausen and Susanne Crewell
Diploma in Meteorology (2001)
University of Munich, Germany.
Thesis title: A model study on ozone mini-holes: Temporal and spatial variability and impact on stratospheric ozone chemistry.
Thesis advisors: Volker Grewe and Robert Sausen.
Dr. Julie Tolu
Senior Scientist
Research interests
My research interests and objectives lie at the interface of analytical chemistry and environmental sciences and particularly on the development of innovative analytical techniques that enable us to tackle environmental issues from new perspectives. My research is focused on the speciation and fate of toxic trace elements, and the molecular composition and fate of organic matter (OM) in environmental compartments, as the cycles of these two biogeochemical fractions are closely related. I am interested in improving our understanding of biochemical transformations of trace metals and OM as well as of the factors and processes involved in spatial and temporal distributions of these two fractions. My previous research projects were focused on terrestrial and aquatic ecosystems and my research at Eawag/ETH will also address the speciation/composition and fate of trace metals and OM in atmospheric deposition.
Technical and analytical expertise
- Major/trace elements quantification: ICP-MS; ICP-OES; XRF
- Trace metals speciation: LC-ICP-MS; GC-ICP-MS
- Organic matter composition: Pyrolysis-GC-MS; FTIR; Temperature Desorption-FTIR-MS
- Field sampling: sediment cores; waters
Education and former positions
Postdoc (2012-2015)
Department of Ecology and Environmental Science (EMG), University of Umeå, Sweden
Research topic. Organic matter composition in lake ecosystems: sources and transformations, changes during the Holocene, and relation with trace metals cycling
PhD in Analytical and Environmental Chemistry (2012)
University of Pau, France.
Thesis title: Speciation and mobility of selenium in soils: a contribution to long-term prediction of Se behavior in soils.
Thesis advisors: Martine Potin-Gautier, Isabelle Le Hécho, Maïté Bueno and Yves Thiry
MSc in Water Chemistry and Microbiology (2008)
University of Limoges/Poitiers, France
Thesis title. Stability of Cu and Pb bearing-phases in sediments and mine tailings of the Bistrita river mine basin in Romania.
Thesis advisors. Alexandra Courtin-Nomade et Cécile Grosbois
Engineer diploma in Environmental Sciences and Management
National Engineering School (ENSIL), Limoges, France
Internship: Research Department of Wetsus, Centre of excellence for sustainable water technology, Leeuwarden (Netherlands)