Chemical Dynamics of Arsenic in the Environment: – Implications for rice
cultivation in Bangladesh
Supervisor:
Dr Gary Owens, Future Fellow – Mawson Institute, GPO Box 2471, Adelaide SA 5001, Australia
Phone: +61 8 8302 5043. Email: gary.owens@unisa.edu.au
Area: Environmental Science
Suitable for: PhD and Masters
Abstract:
Arsenic (As) is a colourless and odourless poison where long-term sub-lethal exposure has long
been associated with increased human health risk and the development of various cancers. In
a number of South East Asian countries, such as Bangladesh, As contaminated groundwater is
not only used as a source of drinking water but is also used extensively for the irrigation of
agriculturally important food crops, such as rice which is the Asian staple. There is now
growing concern that such widespread practices may lead to direct food chain contamination,
increased human health risk and long-term detrimental effects on both soil and crop quality.
Worldwide typical background levels of As in soils range from 5-10 mg kg-1 with an average
concentration of 7.4 mg kg-1 for American soils and the natural background concentration of
As, where no anthropogenic sources exist, is typically < 10 mg kg-1. However, continued
irrigation of crops with As contaminated water may increase soil As concentrations if the
added As is retained by the soil. The clay content of the soil would influence As sorption
characteristics and bioavailability with mobility of As being enhanced under anoxic conditions.
The consequences of elevated As soil levels may ultimately result in lower crop yields and
increased As uptake by crops, which would have a direct impact on the standard of living for
the Bangladeshi farmer by negatively impacting on crop quality and lowering household
income. However, the accumulation of As in rice seems to be dependent on the particular rice
species cultivated and the farming practices used.
In this project the distribution and severity of As in agricultural soils from Bangladesh will be
determined and the relationship between As bioavailability and common soil parameters
quantified. Furthermore the dynamics of As in the water-soil-plant system will be examined to
determine if agricultural practice or rice species are responsible for the variability of As
concentrations in rice. The insights gained on As dynamics in agricultural systems will be used
to develop techniques that promote decreased transport of available As to edible plant parts,
thus decreasing As dietary exposure.
Related references:
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Stanislav Rapant and Katarına Krcmova (2007) Health risk assessment maps for arsenic groundwater
content: application of national geochemical databases, Environmental Geochemistry and Health, 29, 131141.
A.P. Reis, A.J. Sousa, E. Ferreira Da Silva and E. Cardoso Fonseca (2005) Application of geostatistical
methods to arsenic data from soil samples of the Cova dos Mouros mine (Vila Verde-Portugal,
Environmental Geochemistry and Health, 27, 259–270.
Nasreen Islam Khan, Gary Owens, David Bruce and Ravi Naidu (2009) Human Arsenic Exposure and Risk
Assessment at the Landscape Level: A Review, Environmental Geochemistry and Health, 31 (Suppl. 1),
143-166.
Nasreen Islam Khan, Gary Owens, David Bruce and Ravi Naidu (2009) An Effective Dietary Survey
Framework for the Assessment of Total Dietary Arsenic Intake in Bangladesh: Part-A – FFQ Design,
Environmental Geochemistry and Health, 31 (Suppl. 1), 207-220.
Nasreen Islam Khan, David Bruce, Ravi Naidu and Gary Owens, (2009) Implementation of Food Frequency
Questionnaire for the Assessment of Total Dietary Arsenic Intake in Bangladesh: Part-B – Preliminary
Findings, Environmental Geochemistry and Health, 31 (Suppl. 1), 221-238
About Adelaide:
Adelaide is the capital of South Australia and offers a very high standard of living (top 6 in the
world according to “The Economist”), with great climate, food, wine, beautiful unspoiled
nature and beach environments, in an inexpensive setting.
The Mawson Institute (MI) has recently been established at the University of South Australia,
with strong support from the South Australian Government to research new manufacturing
technologies. Manufacturing is an important and substantial part of South Australia’s
economic base. The MI promotes a strategy based upon strong basic and applied research
that encourages scientific and technological innovation within the manufacturing sector.
Fundamental to this is the Institute’s multidisciplinary approach, building research teams in
concentrations that encompass a diverse range of disciplines, and collaboration with partners
from both academia and industry.
The institute is based in two new state-of-the-art buildings with outstanding research facilities
(see photo of the MM building).
For more information on this project please contact the supervisor.