Rick Donselaar (KU Leuven)
Abstract
Groundwater contamination by naturally-occurring (or: geogenic) arsenic (As) is an emerging global health concern. Millions of people worldwide are exposed to the contaminant on a daily basis via drinking water, irrigation and food consumption, and can develop chronic illnesses grouped as arsenicosis. Densely-populated areas in Holocene alluvial basins such as the Ganges-Meghna-Brahmaputra Delta, Red River and Mekong Delta are severely affected. Pinpointing the As hotspots by collection and inventory of As-concentration data in aquifers is a tedious and challenging process, given the sheer magnitude of the problem, and hampers the implementation of sustainable As mitigation strategies.
Despite the unpredictably large geospatial variability in As concentrations, recent research advances show that the interaction of two factors is pivotal for As-hotspot occurrence in the shallow aquifer domain: (a) the key role of microbial metabolism in the reductive dissolution process of As-bearing Fe(II) oxy-hydroxides in anoxic oxbow lakes rich in labile organic matter, and (b) the geomorphological heterogeneity of the alluvial landscape prone in As toxicity, which can be translated as porosity-permeability anisotropy, and controls the occurrence of As hotspots in four-way stratigraphic traps, similar to the accumulation of hydrocarbons.
Awareness of this interaction allows for the construction of predictive geospatial models by integrating remotely-sensed satellite imagery and digital elevation data of the Holocene alluvial-plain geomorphology in combination with GIS-based population databases and machine learning techniques. The models can be applied on a global scale for the identification of large swathes of As hotspots in Holocene alluvial plains.
About the presenter
Rick Donselaar graduated with a MSc degree in geology from the University of Utrecht, and received his Doctor of Science degree from Delft University of Technology (TU Delft) with a thesis on the sedimentary architecture of transgressive barrier island systems. In 1980, he started working as research associate at the University of Utrecht, and later as lecturer in sedimentology. From 1987 onward he worked at TU Delft, where he retired in Oct. 2019 as Associate Professor in Sedimentology. He has been instrumental in establishing the research in geological reservoir characterization at TU Delft. Since 2017 he is Visiting Professor in Sedimentology at the University of Leuven, Belgium. He is professional member of the IAS, SEPM, IGA, Associate Editor of the Netherlands Journal of Geosciences, and Member of the EMSO ERIC Advisory Committee.
The focus of his current research and publications are in the field of the modelling of fluvial reservoirs, with applications in the fields of geothermal energy and (un)conventional hydrocarbon exploitation, and natural arsenic remediation. Rick has led many field trips for oil companies and academia to show the results of his research.
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