The role of organics in the mobilization of arsenic in shallow aquifers

  • Wafa Al Lawati

Student thesis: Phd

Abstract

Over a hundred million people across the globe, and particularly in Asia, are chronicallyexposed to high concentrations (>10 ppb) of geogenic arsenic (As) in shallow reducinggroundwaters utilised as drinking water. It is widely accepted that As mobilisation fromsediments into these groundwater requires active metal-reducing microbes and electrondonors such as organic matter (OM). Although OM have been characterised in fewaquifers, there is a dearth of data on other As rich aquifers.In this work, we further investigate the correlation between As release from aquifers andthe OM/microbial communities present. The key findings of this work are:i. OM in Vietnamese and Taiwanese As hotspot areas originates from multiple sources.This is comparable to previous studies in Cambodia and West Bengal, indicating thatOM originates from similar sources in all the areas studied up to date, regardless ofthe age (Holocene/Pleistocene) and the sediment source (Himalayas/non-Himalayas).This suggests that similar electron donors, such as petroleum derived HMW nalkanes,are present in all these groundwater aquifer sediments.ii. No noticeable differences in OM biomarker distribution patterns were observedbetween sediments from two contrasting groundwater As concentration sites (e.g.
Date of Award31 Dec 2012
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorDavid Polya (Supervisor) & Bart Van Dongen (Supervisor)

Keywords

  • arsenic, organic matter

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