Mercury Pollution from Small Scale Gold Mines in Agricultural Lands

Abstract

Abstract Small scale gold mines widely spread in developing countries, including Indonesia. Most miners use mercury (Hg) in an amalgamation process to separate gold from its ores. This process produces a waste as mercury-containing slurries which is eventually discharged to surrounding water streams, potentially creating ecosystem pollution. If the polluted water is used for irrigation to surrounding ricefields, mercury may stay and accumulate in streambed sediments and irrigated soils and enter the food chain, including human consumption. This research was aimed to assess pollution potential in stream water and ricefields surrounding small scale gold mines in Lebong District, Bengkulu, Indonesia. This research was conducted from November to December 2018. Field activities included collecting 9 water samples, 6 sediment samples, 3 soil samples, and 3 plant samples in different locations. Laboratory analysis were carried out at the Soil Science Laboratory, University of Bengkulu, Bengkulu and the Integrated Research and Testing Laboratory (LPPT) Gadjah Mada University, Yogyakarta, Indonesia. The results showed that all water, streambed sediment, soil, water, and plant tissue samples contained mercury and most of their concentrations exceeded the threshold values. The highest Hg concentrations were found 58.19, 16.85, and 15.44 ppm the streambed sediments, rice plants, and ricefield soils respectively, while a relatively lower Hg (0.044 ppm) was found in the stream water.