The 5th International Conference on Advances in Civil and Ecological Engineering Research (ACEER 2023)

Abstract: Understanding the geological processes controlling geogenic arsenic (As) contamination in groundwater is crucial for management and mitigation of the problem. Based on our recent coring and dating results on Jianghan Plain of the central Yangtze river basin, we herein propose a conceptual model arguing that present groundwater As contamination in Jianghan is destined by interaction between sea level change and landscape evolution since the last ice age. Over the last ice age, the global sea level declined from a near-present level to the last glacial maximum (LGM, ~29-17 thousand years ago (ka)) low stand of ~130 m below, leading to headward erosion that could propagate over 1400 km upstream, forming incised valleys and interfluves, leading to depletion of organic matter in pre-LGM sediments and formation of oxidized stiff clay capping the interfluves, thus As mobilization in pre-LGM sediments was limited; afterwards, during the last deglaciation (~17-7 ka), rapid sea level rise induced fast filling of incised valleys by sandy sediments, which were coated with As bearing iron-hydroxides (FeOOH) and interbedded with organic matter owing to an ameliorated climate; when sea level approached today’s level at ~7 ka, decelerated sea level rise and landscape transformation due to valley filling gave rise to slow deposition of fine-grained sediments atop the fast valley fill, creating an anaerobic condition below, which in turn led to reductive dissolution of FeOOH and release of As. Therefore, the fast-infilling sediments deposited during the last deglaciation within the incised valleys became nowadays the major sources of high-As groundwater, while groundwater in pre-LGM sediments are generally As free. Evidenced by the published data, we derived that the conceptual model applies in many other regions around the world, as sea level change imposes worldwide influences on landscape evolution. Therefore, our proposal may provide a global solution for groundwater As contamination.

Biography: Prof. Zhongping Lai is currently a professor in Shantou University, and the head of luminescence dating laboratory and Quaternary geology & marine geology group. He obtained his PhD in 2005 from Oxford University as a Clarendon Scholar. He was then awarded an Alexander von Humboldt Fellowship and spent nearly two years in Marburg and Bayreuth Universities in Germany. He came back to China in late 2007 in Chinese Academy of Sciences (2007-2014), in China University of Geosciences (2014-2018), and in Shantou University since 2018. He has published more than 170 papers in international SCI journals, such as Earth and Planetary Science Letters, Geophysical Research Letters, Catena, Quaternary Science Reviews, Geomorphology, Quaternary Geochronology, Science of the Total Environment, Environmental Pollution, Frontiers in Marine Science. In ResearchGate, he has an h-index of 46 and a citation of >6200.
He is currently the Editor of “Catena” and and a member of editorial boards of “Geochronometria”. He has also served as associate editors for both "Quaternary Research (2010-2017)" and "Aeolian Research (2010-2017)", and as reviewers for British NERC, Switzerland NSF, and Norway NSF. He was selected in both lists, established by Stanford University, of the “World's Top 2% Scientists 2021: Career-long impact”, and of the “World's Top 2% Scientists: Single year impact” for both 2020 and 2021.
His main research interests include: (1) Quaternary geology, marine geology and geochronology; (2) Coupling of Sea level, delta, fluvial system and land surface processes; (3) Mechanism of arsenic pollution in underground water associated with global climate change and sedimentology; (4) Luminescence dating in both application and technique development.