Download 2017_22: The effect of climate change on arsenic in

2017_22: The effect of climate change on arsenic in
drinking water in Bangladesh
Supervisors: Dr Dominik Weiss ([email protected]), Professor Ramon Villar
(Chemistry); Chris Johnston (Bio-Nano-Consulting), Dr Pascal Salaun (University of
Liverpool)
Department: Earth Science & Engineering
In this PhD project, we aim to investigate the effect of increasing groundwater salinity
due to climate change on the release of arsenic from aquifers and on the removal
efficiency of arsenic in water treatment facilities in Bangladesh.
A study of the International Union for the Conservation of Nature (IUCN) published in
2015 highlighted the climate change vulnerability of drinking water supply
infrastructure in coastal areas of Bangladesh. The impacts of climate change on water
supplies directly affect suitable development of the country and puts at rest poverty
reduction. Water supply will be crucially affected by climate change in many ways in
Bangladesh. A key threat is from sea level rise and the subsequent salinity intrusion.
This process could increase expenses for water treatment mechanisms. This in turn
will affect access to safe drinking water options. This changed physical environment
will affect public health issues and coast lively hood. The study by the IUCN predicts
that the salinity front in Bangladesh will move towards inland from the south of
Bangladesh. Based on model prediction, the population exposed to high salinity is
expected to increase to 13.6 million in 2050. Pond sand filter have been proposed as
one of the major low cost technology to address the problem of increasing saline water
following climate change.
The increase in salinity will profoundly affect the surface chemistry of aquifers and the
efficiency of sorbents used in water treatment to remove toxic elements such as
arsenic. The release of arsenic contained in sediments hosting drinking water
reservoirs is a well-documented threat to human health in Bangladesh affecting
millions of people. The increase in salinity likely leads to an increased release of
arsenic from sediments due to ion exchange processes and/or increased dissolution
of mineral oxides. The increase in salinity will also effect the efficiency of arsenic
removal plants because of increased competitive adsorption. This process will be a
particular threat to the pond sand filter (PSF) , which are increasingly used as low cost
technology to improve water quality. PSFs are based on sand which is well known to
adsorb arsenic much less effective than iron oxides and other mineral oxides.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet
Science and Solutions for a Changing Planet
To address these question, we will conducted field and laboratory experiment to
assess the chemistry of arsenic in saline solutions and in particular at the mineral
water surface interactions. We will study the interface process macroscopically using
batch and column experiments and microscopically using spectroscopy techniques
including X-ray, UV/Vis, XPS and FTIR. This data will be used to develop surface
complexation and reactive transport models which will ultimately allow us to develop
a predictive assessment of the effects of increased salination on arsenic release in
aquifers and on adsorption in pond sand filters.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet