WP21 Evaluation of Groundwater Communication with Surface Water and Contributions to Sediment Toxicity
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall
(INO-1117-794551) Contamination of Arsenic in Groundwater from Lower Mekong Basin.
Inoue, S1, Agusa, T1, Minh, T2, Tu, N3, Tuyen, B3, Chamnan, C4, Tana, T5, Iwata, H1, Tababe, S1, 1 Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime, Japan2 Faculty of Agriculture, Ehime University, Matsuyama, Ehime, Japan3 Nong Lam University, Ho Chi Minh, Vietnam4 Department of Fisheries, Ministry of Agriculture, Forestry and Fisheries, Phnom Penh, Cambodia5 Cabinet of the Council of Minister, Phnom Penh, Cambodia
ABSTRACT- The present study reports the levels and possible toxic effects of Arsenic (As) and 20 other trace elements in the ground water collected from the lower Mekong River Basin in Vietnam (September 2003 and May 2004) and Cambodia (September 2004). Concentrations of Arsenic were considerably higher in Cambodia (<0.1 to 1,930 
g/L) than in the adjacent Vietnam (<0.1 to 411 g/L). The levels of As in Cambodia were comparable to the world′s well known Arsenic polluted regions, such as Bangladesh and West Bengal in India. While only 16% of the As values in Vietnam exceeded the WHO guidelines in drinking water, 57% of the samples from Cambodia had concentrations more than the guideline values. In addition, concentrations over the WHO drinking water guideline were found for Manganese (Mn) and Barium (Ba) in the samples from both the countries. In Cambodia the percentage of the samples which had Mn above the guideline values is 33% and in Vietnam 34% of the samples exceeded the limit. The corresponding values for Cambodia and Vietnam are 10 and 6.3%. Our results clearly indicated that groundwater in the lower Mekong Basin in Cambodia and Vietnam was contaminated with As, Mn and Ba. From our findings, it can be concluded that the inhabitants of Lower Mekong River Basin are presently exposed to a high chronic risk of As, Mn and Ba toxicity by the consumption of contaminated ground water in their every day life.
Key words: arsenic, groundwater, Lower Mekong Basin