Distribution of mercury contamination on paddy fields in various levels of soil depth in gold mine area at Sub-District Hutabargot, Mandailing Natal Regency, Indonesia

Unauthorised Gold Mining in Mandailing Natal Regency could serious problems for the environment and human health. It is because waste from the amalgamation process contains mercury released into the waterways that are irrigation sources. The main damage impact from the mercury waste released into irrigation canals would be seen on the paddy field. For this reason, it is necerssary to tests and studies to see the contaminated level of mercury on paddy fields. This research was conducted from June to July 2023 in Sub-District Hutabargot, Mandailing Natal Regency by took soil sampling in the 0-10 cm, 11-20 cm, 21-20 cm, 31-40 cm, 41-50 cm, 51-60 cm, 61-70 cm, 71-80 cm, 81-90 cm, and 91-100 cm on soil depth in 7 sampling points. The resulting study obtained at least 170 amalgamation points that the waste released into the waters. The mercury content on the paddy soil in Sub-District Hutabargot which is irrigation irrigated by amalgamation process exceeding the threshold. There is an increase of mercury content in the 30 cm soil depth and then decreases with increasing soil depth. For a depth of more than 60 cm, the mercury content on the paddy soil is under the threshold.