Research Partnerships:
- Arsenic concentration found in
alluvial sediments in the upper Mekong delta with Dr. Scott
Fendorf
Dr. Scott Fendorf; Stanford
University, CA.
PolizzottoGSA2005new.pdf
- Bioaccumulation of arsenic in
the food chain with Dr. T. P. Murphy of Environment Canada.
Mercury in Cambodia.doc
- General survey of arsenic
contamination of the upper Mekong delta and seasonal arsenic
effects with Dr. Michael Berg of EAWAG Switzerland.
- Sediment transport in the
Mekong river basins, water quality and GIS training, sewer
outfalls of Phnom Penh; with Dr. Kim Irvin of Buffalo State, State
University of New York.
Mercury in Cambodia.doc
- Measurement of localized rain, GIS, and water
quality indexes; Dr. Stephen Vermette of
Buffalo State, State University of New York.
-
Mekong River Carbon Biogeochemistry with Dr.
Jeffrey Richey, School of Oceanography, University of
Washington, Seattle, WA.
River Encyclopedia.pdf
- Biological precursors to
arsenicosis with Dr. David Polya, Manchester University.
polya.pdf
PolyaMinMag.pdf
groundwaterposter.pdf
- Arsenic in the Mekong Delta with Dr. Shawn
Brenner; Boise State University, Boise, ID.
Student Research Partners:
•
Matt Polizzotto PhD student at Stanford
University Department of Geological and Environmental Sciences:
"Arsenic is a contaminant in groundwater throughout Southeast
Asia, and because many people throughout the area rely on
groundwater for drinking water, this is an issue of primary
concern. The source of arsenic is the natural sediments but the
reasons why it has been released to the groundwater rather than
staying on the solid sediments is unknown. We have conducted
extensive research in Bangladesh, where the arsenic problem is
most acute, and believe that arsenic is being released from soils
near the ground surface and subsequently is brought down into the
ground as surface water recharges the aquifer. However, due to a
variety of human impacts and changes to the environmental system
in Bangladesh, it is very difficult to confirm our hypothesis.
Therefore, we have since begun studying arsenic in Cambodia, where
such human impacts are not present, and where the problem is
relatively understudied despite the fact that many people have
been adversely affected.
We have teamed up with RDI to develop a field site encompassing
about 10 sq. km in the Kien Svay district between the Mekong and
Bassac Rivers, and in order to obtain a "3-dimensional" idea of
how arsenic concentrations vary in the groundwater, we have
installed wells that retrieve water from different underground
depths throughout our field area. We routinely take samples from
these wells to measure arsenic and other chemical constituents
that may give us an idea of where arsenic is coming from and why
it is being released into the groundwater. In addition, we have
been monitoring water heights in wells, ponds, and rivers to get
an idea of how water might be moving from one place to another,
and therefore where arsenic in this water might be coming from and
how it might be entering the groundwater. So far our findings
reveal that arsenic concentrations vary across different locations
and different well depths but are generally at dangerous levels
throughout the region. Groundwater heights are dominated by
seasonal fluctuation of the Mekong River but most ponds are not,
indicating that groundwater may move to and from the river but has
limited contact with other surface water sources. Our results are
similar to many conditions reported for Bangladesh, and so we hope
our research will not only be beneficial to those in Cambodia, but
will also be of widespread utility throughout Southeast Asia."
•
Ben Kocar, PhD student at Stanford University
Department of Geological and Environmental Sciences: "Arsenic
is a toxic and carcinogenic element found in soils and sediments
throughout the world. Well water in many countries, including
Cambodia and Bangladesh, is contaminated with arsenic at
concentrations high above safe drinking water standards set by the
World Health Organization. Unfortunately, the cause(s) of these
high arsenic concentrations remain unclear, and mechanisms of
arsenic mobilization within subsurface sediments remain elusive.
It is known that arsenic binds strongly to iron oxides residing in
the soil (iron oxides—rust—often impart a red color to the soil,
like those found in the Southeastern United States). However,
carbon may feed microbes living in the soil, which in turn
dissolve these iron oxides and release bound arsenic. High
concentrations of dissolved organic carbon (mostly from rotting
plant material) are found within Cambodian surface waters,
especially in very swampy areas, known as "preaks." Thus, we study
the release mechanisms of arsenic within the soils and sediments
of these seasonally flooded areas, where organic carbon, sulfate,
and other aqueous constituents may induce the release of arsenic."
•
Samantha Ying, PhD student at Stanford
University Department of Geological and Environmental Sciences:
"Soil bacteria are able to utilize a variety of elements for
energy to grow. Some of these elements include nitrogen,
manganese, iron, and even arsenic. When the bacteria reduce
these elements arsenic may mobilize and eventually enter aquifers
and contaminate drinking water. Currently, we are performing
experiments that can help identify these microbes and how they are
affecting arsenic mobility within the soil environment. Two types
of bacteria that are of interest are those that can reduce iron or
oxidize manganese. Arsenic binds to oxidize iron (iron oxides =
rust) very strongly, but when bacteria reduce these iron oxides
for energy, the arsenic is then released from the soil and can
then enter the aquifer. Arsenic also binds very strongly to
manganese oxides, prohibiting arsenic from moving to the
groundwater. Bacteria that can form these manganese oxides by
oxidizing dissolved manganese may, therefore, help to keep arsenic
from entering the well water. Overall, a better understanding of
the microbes and their activities within soils of Cambodia can aid
in assessing the mechanism responsible for arsenic contamination
in aquifers of Southeast Asia."
• The
University of North Carolina (UNC) School of Public Health (www.unc.edu/sobseylab)
is beginning a research program on drinking water and
environmental health in Cambodia, in association with RDI. Joe
Brown, PhD student in environmental sciences and engineering,
began work at the RDI laboratory in November 2005. UNC's research
focuses on household-scale water treatment with ceramic filtration
and slow sand systems, as well as ways of improving water storage
containers to keep water safe and free of microbial
contamination. Joe is also working to improve the microbiological
effectiveness of ceramic filters (already highly effective against
bacteria and protozoan parasites) by using low-cost materials to
enhance waterborne virus removal.
Brown's
research team includes five Cambodian staff members who will be
the country's next generation of environmental microbiologists!
• Ryan Sinclair from Tulane
University is researching Solar Disinfection in the Resource
LABS for his doctoral dissertation study.
More information regarding SODIS can be
found here: SODIS Page
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Other Partnerships:
• RDI has hosted
Workshop training for for a
variety of government agencies in Cambodia and faculty from the
Royal University of Phnom Penh. The training was made possible
through a partnership between SUNY, Resource Development
International - Cambodia (a U.S. registered NGO), and Environment
Canada (a Canadian Federal Government Agency).
• RDI has also partnered with
Tearfund and the British Embassy to complete a karaoke CD on abstinence, faithfulness in
marriage, and AIDS related issues. Sir Cliff Richard, of Great
Britain, was recently in Cambodia helping promote this program.
• The creative team at Puppet Productions
of Desoto, TX is also a major contributor to RDI's education
projects and happily responsible for this web site.
RDI would like to thank:
• Advanced Drainage Systems, Inc.
in Liberty, MO for donating three laptops for field data
collection and water analysis. •
Louisville Water Company for donating a used gas chromatograph to
the RDI laboratory. • The hundreds of
volunteer teams of youth and adults who have offered their sweat
and muscle to building and education projects over the years. |
