Using high-resolution in situ radon measurements to determine groundwater discharge at a remote location: Tonle Sap Lake, Cambodia

  • W. C. Burnett
  • R. N. Peterson
  • S. Chanyotha
  • G. Wattayakorn
  • B. Ryan
Article

DOI: 10.1007/s10967-012-1914-8

Cite this article as:
Burnett, W.C., Peterson, R.N., Chanyotha, S. et al. J Radioanal Nucl Chem (2013) 296: 97. doi:10.1007/s10967-012-1914-8

Abstract

Tonle Sap Lake (Cambodia) is the largest freshwater lake in SE Asia, and is reported to have one of the highest freshwater fish productions anywhere. During the dry season (November–April) the lake drains through a tributary to the Mekong River. The flow in the connecting tributary completely reverses during the wet monsoon (May–October), adding huge volumes of water back to the lake, increasing its area about fourfold. We hypothesize that nutrients are at least partially delivered via groundwater discharge, especially during the draining portion of the annual flood cycle. We surveyed over 200 km in the northern section of the lake using a customized system that measures natural 222Rn (radon), temperature, conductivity, GPS coordinates and water depth while underway. Results showed that there were portions of the lake with significant enrichments in radon, indicating likely groundwater inputs. These same areas were generally characterized by lower electrical conductivities. Samples collected from nearby wells also showed a general inverse relationship between radon and conductivity. Our data suggest that groundwater pathways are important, accounting for roughly 10–20 % of the freshwater flow of the Tonle Sap tributary (connection to the Mekong River), the largest single source of fresh water to the lake. Nutrient inputs from these inputs, because of higher concentrations in groundwater, will be correspondingly higher.

Keywords

Radon Tonle Sap Lake Groundwater discharge Remote locations Nutrients 

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2012

Authors and Affiliations

  • W. C. Burnett
    • 1
  • R. N. Peterson
    • 2
  • S. Chanyotha
    • 4
  • G. Wattayakorn
    • 3
  • B. Ryan
    • 5
  1. 1.Department of Earth, Ocean and Atmospheric SciencesFlorida State UniversityTallahasseeUSA
  2. 2.Center for Marine and Wetland StudiesCoastal Carolina UniversityConwayUSA
  3. 3.Department of Marine Science, Faculty of ScienceChulalongkorn UniversityBangkokThailand
  4. 4.Department of Nuclear Engineering, Faculty of EngineeringChulalongkorn UniversityBangkokThailand
  5. 5.Department of Sustainability, Environment, Water, Population and CommunityCanberraAustralia

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