GIS application for mineral resource and environmental management : case study on zinc deposit, Mae Sot district, Tak province

Abstract

The International Water Management Institute (IWMI) and the Thai Department of Agriculture (DOA) had conducted a research on cadmium contamination in soils and rice grains from a small agricultural area of Mae Sot District, Tak Province during 2001-2003. Theirchemical analyses of cultivate soil along the south of Mae Tao creek located in the drainage system surrounding the vicinity of zine potential area reveal significantly high levels of cadmium contamination. This site has become a cadmium contaminated area that directly impacts the environment and human health in Mae Sot area. This region has been well known as a high-quality jasmine rice producing area; in addition, it is partly occupied by the economic zinc deposit, named Padaeng. Therefore, to remediate the agriculture area and also to maintain the zine ore economic value without or less impact to the area is necessary. Consequently, Geographic Information System (GIS) has been considered as a tool for approaching this aspect. The goal of a GIS application is to gather all data, both spatial and attribute, before transform them, through overlying and analytical operatios, which can support the decision-making process. Data which was taken into account include chemical data of soil, stream sediment, and other regional information such as topography, geologic structure, landuse and rainfall data. Moreover, satellite images taken in a few different periods were interpreted to explain the changes of sedimentation and landuse. The results of the study indicate source of contamination in Mae Sot District that could be divided into 2 major types. The first major source of cadmium contamination may be from the zine deposit and anthropogenic activities particularly zinc mines that are suspected to be the activation for cadmium distribution and hence contaminated in the lowland area. The second source of the contamination is a cultivation and natural weathering of soil and rock. Moreover, human activities such as deforestation and cultivation which can cause the erosion might be a major source as well. The transportation of the sediment from the zinc deposit area and from the high erosion area is occurred by runoff which usually flows from the the east highland of Mae Sot catchments to the west floodplain area. As a result, a few mitigation and remediation plan for the rehabilitation of the study area are then designed.