Human Health Risk Assessment Associated with Arsenic (As) in Drinking Shallow Groundwater Wells at Ubon Ratchathani Province, Thailand Pokkate Wongsasuluk International Postgraduate Programs in Environmental Management, Graduate school. National Center of Excellence for Environmental and Hazardous Waste Management(NCE-EHWM), Chulalongkorn University Bangkok, Thailand e-mail: pokkate_wong@hotmail.com Srilert Chotpantarat Department of Geology, Faculty of Science. National Center of Excellence for Environmental and Hazardous Waste Management(NCE-EHWM), Chulalongkorn University Bangkok, Thailand email:lertc77@yahoo.com Wattasit Siriwong Thai Fogarty Center, College of Public Health Sciences. National Center of Excellence for Environmental and Hazardous Waste Management(NCE-EHWM), Chulalongkorn University Bangkok, Thailand e-mail: wattasit.s@chula.ac. Abstract— Nowadays there are several problems which are concerned about environment. One of the most important environmental issues today is groundwater contaminated with heavy metals especially arsenic (As) because of their severe toxicity even at low concentrations. Long time ago until nowadays in Thailand people who have lived in this agricultural area generally consume groundwater from their wells located in their farm because they don’t concern about negative effects from heavy metal contamination in groundwater. It is possible that arsenic contaminated in shallow groundwater may cause a potential health effect to consumers. This study aimed to assess the level of the human health risk from lead contaminated in shallow groundwater wells at Ubon Ratchathani province, Thailand. Twelve wells randomly selected for water sampling and Inductively Coupled Plasma Spectrometry-Mass Spectrometry (ICP-MS) used to find out the concentration of arsenic contaminated in shallow groundwater. In addition, questionnaires were completed by face-to-face interviewing with local people who consume shallow groundwater to find their intake rate and finally risk assessment. The results showed that only one well was acceptable level for non-carcinogen which had the Hazard Quotient value of arsenic were lower than one (HQ<1) while the others 11 wells were adverse concern with non-acceptable level which had the Hazard Quotient value of arsenic were higher than one (HQ>1). For carcinogenic effect, the acceptable risk was 10 -6 , this value means the probable possibility that about 1 cancer patients among 1,000,000 people happen. The result showed that all wells were acceptable level of cancer risk (cancer risk < 10 -6 ) while only one well was carcinogenic concern (cancer risk > 10 -6 ). Keywords-Arsenic; Groundwater; Risk assessment; Heavy metal contamination; Ubonratchathani; I. INTRODUCTION Water is one of the essentials that supports all forms of plant and animal life and it is generally obtained from two principal natural sources; Surface water such as fresh water lakes, rivers, streams and groundwater. Nowadays there are several problems which are concerned about environment [4]. One of the most important environmental issues today is groundwater contaminated with heavy metals especially arsenic (As) because of their strong toxicity even at low concentrations [5]. Long time ago until nowadays in Thailand people who have lived in this agricultural area generally consume groundwater from their wells located in their farm because they don’t concern about negative effects from heavy metal contamination in groundwater. In addition, Muang district, UbonRachathani province is the largest area of chilli farms in Thailand and local people also usually consume shallow groundwater in their farms because they don’t know about heavy metal contamination. It is possible that arsenic contaminated in shallow groundwater may cause a potential health effect to consumers. There is thus the need to assess the human health risk associated with arsenic contaminated in shallow groundwater which easy to understand how much people probably sick among 1,000,000 people who consume contaminated shallow groundwater. Moreover, human health risk assessment can be the disease prevention in order to local people who lived and consumed contaminated groundwater in such agricultural area. This research aimed to investigate the concentrations of arsenic in shallow groundwater wells at Muang district, Ubon Ratchathani province and assess the level of the human health risk from arsenic contaminated groundwater. II. METHODOLOGY A. Study area Hua Rua sub-district, Muang district, Ubonratchathani province (Fig.1) is one of the largest areas of chilli farming in Thailand. B. Sampling and chemical analysis The twelve water wells in agricultural area at Muang district, Ubon Ratchathani province were random selected to sample the groundwater. Sampling will be collected during the months of June and August 2010. V2-314 2011 2nd International Conference on Environmental Science and Technology IPCBEE vol.6 (2011) © (2011) IACSIT Press, Singapore