The Republic of Vietnam and the United States (US) militaries began destroying food crops (rice) in November of 1962, primarily via aerial applications in the Mekong Delta and Central Highlands of South Vietnam. Spraying of Agent Blue on mangrove forests and rice paddies just before rice harvest time resulted in the destruction of the standing crop and rendered the land contaminated with arsenic (As). Agent Blue (cacodylic acid, C2H7AsO2) was the most effective of all the Rainbow herbicides in killing rice and grasses. Manufacturing of cacodylic acid began in the late 1950s in the US at the Ansul Company chemical plant in Marinette, Wisconsin and Menominee, Michigan. During the Vietnam War, ocean-going ships were loaded with 208-liter Agent Blue barrels and shipped via the St. Lawrence Seaway to the coast of South Vietnam. Arsenic (As) is a naturally occurring element that is found throughout SE Asia deltas, including the Mekong Delta. Arsenic-contaminated rice and groundwater are growing concerns as neither naturally occurring arsenic nor anthropic arsenic has a half-life and cannot be destroyed. Water-soluble arsenic primarily leaches into the soil root zone and the groundwater. The As in the contaminated rice paddy soil, sediment and water are taken up by fish, shrimp or crop vegetation and trace amounts can end up in the food supply (rice grain) or be bioaccumulated by the fish, shrimp and birds, which, when eaten, are bioaccumulated in the Vietnamese people. This research reinforces the urgent need for mitigation of arsenic exposure from drinking water and food grown in flooded rice production systems. The uptake of trace amounts of As in rice is indeed a critical food security and human health issue and requires mitigation.
References
[1]
Olson, K.R. and Morton, L.W. (2017) Why Were the Soil Tunnels of Cu Chi and Iron Triangle in Vietnam So Resilient? Open Journal of Soil Science, 7, 34-51. https://doi.org/10.4236/ojss.2017.72003
[2]
Mekong River Commission (2010) Mekong River Commission Conference Proceedings. The First Mekong River Commission Summit 2010.
[3]
Moormann, R. (1961) The Soils of the Republic of Vietnam. Ministry of Agriculture.
[4]
Olson, K.R. and Cihacek, L. (2022) How United States Agricultural Herbicides Became Military and Environmental Chemical Weapons: Historical and Residual Effects. Open Journal of Soil Science, 12, 13-81. https://doi.org/10.4236/ojss.2022.122002
[5]
Olson, K.R. and Cihacek, L. (2020) The Fate of Agent Blue, the Arsenic Based Herbicide, Used in South Vietnam during the Vietnam War. Open Journal of Soil Science, 10, 518-577. https://doi.org/10.4236/ojss.2020.1011027
[6]
Olson, K.R. (2023) Review and Analysis: Fate of Arsenic Applied to Canal Shipping Lane Vegetation and United States Military Base Grounds in the Panama Canal Zone. Open Journal of Soil Science, 13, 391-413. https://doi.org/10.4236/ojss.2023.1310018 https://www.scirp.org/pdf/ojss_2023101215530947.pdf/
[7]
Olson, K.R. and Cihacek, L. (2022) Agent Blue Spraying in the Mekong Delta during the Vietnam War: Fate of the Arsenic Based Herbicide Weapon Used to Destroy Rice Crop and Mangrove Forests. Open Journal of Soil Science, 12, 253-294. https://doi.org/10.4236/ojss.2022.127012 https://www.scirp.org/pdf/ojss_2022071415375505.pdf/
[8]
Stellman, J.M., Stellman, S.D., Christian, R., Weber, T. and Tomasallo, C. (2003) The Extent and Patterns of Usage of Agent Orange and Other Herbicides in Vietnam. Nature, 422, 681-687. https://doi.org/10.1038/nature01537
[9]
Institute of Medicine (1994) Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. National Academies Press, 89-90.
[10]
Olson, K.R. (2023) Saigon River Valley: A Navigation, Trade, Mitigation, Invasion, Liberation, and Unification Pathway. Open Journal of Soil Science, 13, 46-82. https://doi.org/10.4236/ojss.2023.132003 https://www.scirp.org/pdf/ojss_2023022115392708.pdf/
[11]
Olson, K.R. (2024) The Secret Toxic Legacies of Chemical Warfare: Agent Blue Use during the 2nd Indochina and Vietnam Wars in Laos, Cambodia, and Vietnam (1961 to 1971). Open Journal of Soil Science, 14, 689-725. https://doi.org/10.4236/ojss.2024.1411034
[12]
Olson, K.R. (2023) Agent Blue: A Secret Military and Environmental Chemical Weapon Used for Food Denial in South Vietnam during the Vietnam Civil War (1962-1965). Open Journal of Soil Science, 13, 151-186. https://doi.org/10.4236/ojss.2023.133007 https://www.scirp.org/pdf/ojss_2023030915103849.pdf/
[13]
Olson, K.R. and Chau, K.M. (2022) Natural and Anthropic Sources of Arsenic in the Groundwater and Soils of the Mekong Delta. Open Journal of Soil Science, 12, 541-570. https://doi.org/10.4236/ojss.2022.1211023
[14]
Speidel, D.R. and Olson, K.R. (2024) Review and Analysis: Evaluation of the Impacts and Consequences of Using Agricultural Herbicides as Military Chemical Weapons in Second Indochina War. Open Journal of Soil Science, 14, 471-498. https://doi.org/10.4236/ojss.2024.148025
[15]
Radke, B., Jewell, L., Piketh, S. and Namieśnik, J. (2014) Arsenic-Based Warfare Agents: Production, Use, and Destruction. Critical Reviews in Environmental Science and Technology, 44, 1525-1576. https://doi.org/10.1080/10643389.2013.782170
[16]
Vilensky, J.A. (2005) Dew of Death. The Story of Lewisite, America’s World War I Weapon of Mass Destruction. Indian University Press.
[17]
Lièvremont, D., Bertin, P.N. and Lett, M. (2009) Arsenic in Contaminated Waters: Biogeochemical Cycle, Microbial Metabolism and Biotreatment Processes. Biochimie, 91, 1229-1237. https://doi.org/10.1016/j.biochi.2009.06.016
[18]
Olson, K.R. and Morton, L.W. (2018) Polders, Dikes, Canals, Rice, and Aquaculture in the Mekong Delta. Journal of Soil and Water Conservation, 73, 83A-89A.
[19]
Agency for Toxic Substances and Disease Registry (ATSDR) (2007) Toxicological Profile for Arsenic. US Department of Health and Human Services.
[20]
Brooks, W.E. (2007) Mineral Commodity Summaries. Arsenic. US Geological Survey.
[21]
Nguyen, P.K. (2008) Geochemical Study of Arsenic Behavior in Aquifer of Mekong Delta, Vietnam. A Dissertation a Degree of Doctor, Kyusha Uni-versity.
[22]
Erban, L.E., Gorelick, S.M., Zebker, H.A. and Fendorf, S. (2013) Release of Arsenic to Deep Groundwater in the Mekong Delta, Vietnam, Linked to Pumping-Induced Land Subsidence. Proceedings of the National Academy of Sciences, 110, 13751-13756. https://doi.org/10.1073/pnas.1300503110
[23]
Yan, X., Chen, T., Liao, X., Huang, Z., Pan, J., Hu, T., et al. (2008) Arsenic Transformation and Volatilization during Incineration of the Hyperaccumulator Pteris vittata L. Environmental Science & Technology, 42, 1479-1484. https://doi.org/10.1021/es0717459
[24]
Schroeder, H.A. and Balassa, J.J. (1966) Abnormal Trace Metals in Man: Arsenic. Journal of Chronic Diseases, 19, 85-106. https://doi.org/10.1016/0021-9681(66)90152-4
[25]
Berg, M., Stengel, C., Trang, P., Hungviet, P., Sampson, M., Leng, M., et al. (2007) Magnitude of Arsenic Pollution in the Mekong and Red River Deltas—Cambodia and Vietnam. Science of The Total Environment, 372, 413-425. https://doi.org/10.1016/j.scitotenv.2006.09.010
[26]
Wikipedia (2025) Arsine. https://en.wikipedia.org/wiki/Arsine/
[27]
Holleman, A.F. and Wiberg, E. (2001) Inorganic Chemistry. Academic Press.
[28]
National Institute for Occupational Safety and Health (NIOSH) (2025) NIOSH Pocket Guide to Chemical Hazards. “#0040”.
[29]
Greaves, I. and Hunt, P. (2010) Chemical Agents. In: Greaves, I. and Hunt, P., Eds., Responding to Terrorism, Elsevier, 233-344. https://doi.org/10.1016/b978-0-08-045043-8.00005-2
[30]
Agency for Toxic Substances & Disease Registry (2012) Medical Management Guidelines for Arsine (AsH3).
Institute National de Recherche et de Sécurité (2000) Fiche toxicologique nº 53: Trihydrure d’arsenic. https://www.inrs.fr/publications/bdd/fichetox/fiche.html?refINRS=FICHETOX_53
Marsh and James (1836) Account of a Method of Separating Small Quantities of Arsenic from Substances with Which It May be Mixed. Edinburgh New Philosophical Journal, 21, 229-236.
[35]
Fowler, B.A. and Weissberg, J.B. (1974) Arsine Poisoning. New England Journal of Medicine, 291, 1171-1174.
[36]
NIOSH (2025) Arsine. Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
[37]
Department of Bacteriology and Pathology, Medical Science Section and Chemical Warfare Service (1920) Collected Studies on the Pathology of War Gas Poisoning. Yale University Press.
[38]
Rokonuzzaman, M., Li, W.C., Man, Y.B., Tsang, Y.F. and Ye, Z. (2022) Arsenic Accumulation in Rice: Sources, Human Health Impact and Probable Mitigation Approaches. Rice Science, 29, 309-327. https://doi.org/10.1016/j.rsci.2022.02.002
[39]
Zhang, X. and Reid, M.C. (2022) Inhibition of Methanogenesis Leads to Accumula-tion of Methylated Arsenic Species and Enhances arsenic Volatization from Rice Paddy Soil. Science of the Total Environment, 29, 309-327. https://www.sciencedirect.com/science/article/abs/pii/S0048969721067723/
[40]
Schmidt, C. (2011) Arsenic in the Air: Geochemistry: Researchers Link Natural Arsines Emissions to Soil Carbon Content. https://cen.acs.org/articles/89/web/2011/02/Arsenic-Air.html/
[41]
Lizama A., K., Fletcher, T.D. and Sun, G. (2011) Removal Processes for Arsenic in Constructed Wetlands. Chemosphere, 84, 1032-1043. https://doi.org/10.1016/j.chemosphere.2011.04.022
[42]
Harte, J., Holdren, C., Schneider, R. and Shirley, C. (1991) Toxic A to Z. A Guide to Everyday Pollution Hazards. University of California Press.
[43]
Altug, T. (2003) Introduction to Toxicology and Food. CRC Press.
[44]
National Academy of Sciences (NAS) (1974) The Effects of Herbicides in South Vi-etnam. Part A Summary and Conclusions. National Academy of Sciences. Commit-tee on the Effects of Herbicides in Vietnam, Division of Biological Sciences, Assembly of Life Sciences, National Research Council.
[45]
Sills, P. (2014) Toxic War: The Story of Agent Orange. Vanderbilt University Press.
[46]
Zierler, D. (2011) Invention of Ecocide: Agent Orange, Vietnam, and the Scientists Who Changed the Way We Think about the Environment. University of Georgia Press. https://doi.org/10.1353/book11509
[47]
US Food and Administration (2020) Arsenic-Based Animal Drugs and Poultry.
[48]
Cognetta, A.B., Wolfe, C.M. and Herbst, A.T. (2016) Palmoplantar Keratoderma and Bowen’s Disease in a Vietnam Veteran: Could Agent Blue be implicated? Australian Journal of Dermatology, 57, c66-c68.
[49]
McMurray, H. and Singaraju, R. (2021) Agent Orange and Agent Blue Exposures. Federal Practitioner.
[50]
Lee Chang, A., Dym, A.A., Venegas-Borsellino, C., Bangar, M., Kazzi, M., Lisenenkov, D., et al. (2017) Comparison between Simulation-Based Training and Lecture-Based Education in Teaching Situation Awareness. A Randomized Controlled Study. Annals of the American Thoracic Society, 14, 529-535. https://doi.org/10.1513/annalsats.201612-950oc
[51]
Stellman, J.M. and Stellman, S.D. (2018) Agent Orange during the Vietnam War: The Lingering Issue of Its Civilian and Military Health Impact. American Journal of Public Health, 108, 726-728. https://doi.org/10.2105/ajph.2018.304426
[52]
National Academies of Sciences, Engineering, and Medicine (2018) Veterans and Agent Orange. The National Academies Press. https://doi.org/10.17226/25137
[53]
Martin, M.F. (2021) US Agent Orange/Dioxin Assistance to Vietnam. https://www.congress.gov/crs-product/R44268?q=%7B%22search%22%3A%22R44268%22%7D&s=1&r=1/
[54]
Saha, J.C., Dikshit, A.K., Bandyopadhyay, M. and Saha, K.C. (1999) A Review of Arsenic Poisoning and Its Effects on Human Health. Critical Reviews in Environmental Science and Technology, 29, 281-313. https://doi.org/10.1080/10643389991259227
