HR: 1340h
AN: H23F-1493    [Abstracts]
TI: Human Health Impact of Fluoride in Groundwater in the Chiang Mai Basin
AU: Matsui, Y
EM: matsui@env.t.u-tokyo.ac.jp
AF: The University of Tokyo, Department of Urban Engineering, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 Japan
AU: Takizawa, S
EM: takizawa@env.t.u-tokyo.ac.jp
AF: The University of Tokyo, Department of Urban Engineering, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 Japan
AU: Wattanachira, S
EM: suraphong@eng.cmu.ac.th
AF: Chiang Mai University, Department of Environmental Engineering /National Research Center for Environmental and Hazardous Waste Management, Chiang Mai, 50200 Thailand
AU: Wongrueng, A
EM: aunnop_tom@yahoo.com
AF: Chiang Mai University, Department of Environmental Engineering /National Research Center for Environmental and Hazardous Waste Management, Chiang Mai, 50200 Thailand
AU: * Ibaraki, M
EM: ibaraki.1@osu.edu
AF: Ohio State University, Dept. Geological Sciences, 125 South Oval Mall, Columbus, OH 43210 United States
AB: Chiang Mai Basin, in Northern Thailand, is known as a fluorotic area. Groundwater of the Chiang Mai Basin has been gradually replaced by contaminated surface water since the 1980's. People have been exposed to fluoride contaminated groundwater since that time. As a result, harmful health effects on dental and skeletal growth were observed in the 90's. These include dental and skeletal fluorosis. Dental fluorosis is characterized by yellow or white spots on teeth and pitting or mottled enamel, consequently causing the teeth to look unsightly. Skeletal fluorosis leads to changes in bone structure, making them extremely weak and brittle. The most severe form of this is known as ``crippling skeletal fluorosis,'' a condition that can cause immobility, muscle wasting, and neurological problems related to spinal cord compression. This study focuses on the problematic issue of the Chiang Mai Basin's groundwater from the viewpoint of fluoride occurrence and current health impacts. Chiang Mai and Lamphun Provinces comprise the Chiang Mai Basin. Fluoride rich granites or fluorite deposits are scattered across the mountainside of the Lamphun Province. Tropical savanna climate conditions with seasonal monsoons bring more than 1,000 mm of annual precipitation, which can prompt weathering of minerals containing fluoride. The Ping River dominates the Basin, and the main eastern tributary of the Ping River runs through the Lamphun Province. The Basin has geological units composed of lower semi-consolidated Tertiary fluvial and upper unconsolidated Quaternary alluvium deposits. The main aquifers are in the upper unconsolidated unit. High fluoride concentrations tend to be observed in the aquifer located in lower part of this unconsolidated unit. We have been investigating two areas in the Basin. These two locations are similar with respect to geological and hydrological settings. However, one area in which groundwater is Ca-bicarbonate dominant has a low fluoride occurrence. Groundwater of the other area contains a high fluoride concentration and is Na-bicarbonate dominant. We will present how naturally-occurring fluoride found in this groundwater has impacted the health of a large portion of residents in the Chiang Mai Basin, and we will explain the mechanism that differentiates Ca concentration, which controls fluoride concentration in groundwater, between different areas in the Basin.
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
DE: 1834 Human impacts
SC: Hydrology [H]
MN: Fall Meeting 2005