Distribution Patterns of Arsenic in Groundwater Using Spatial Autocorrelation in Rural Area at Huai Kao Sarn Watershed Ubon Rachathani Province

Arsenic is found in the natural environment as it is used in insecticides and pesticides for protection of rice. As part of this process, it has contaminated soil and groundwater, exposing people to its effects by touch, breathing, and drinking. This study aimed to assess the arsenic in groundwater and analyze the spatial distribution patterns of arsenic contamination by using spatial autocorrelation in groundwater. Groundwater data were collected from 31 wells with global positioning system (GPS). Arsenic contamination of the groundwater analyzed by Graphite Furnace Atomic Absorption. Spatial autocorrelation statistics were analyzed by Anselin Local Moran's I for the patterns of distribution of arsenic contamination. In addition, groundwater of arsenic contamination was modeled by indicator kriging method. The Results showed that 22 groundwater sources were contaminated with arsenic. The application of spatial correlation statistics with Moran's I revealed a cluster spatial pattern with statistical significance of arsenic in groundwater especially in the south of the study area. Keywords: arsenic, groundwater, spatial autocorrelation