Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2023

Small-scale mercury mining on Seram Island Mollucus Province Indonesia (#171)

Yusthinus T Male 1 , Amanda Reichelt-Brushett 2 , Albert Nanlohy 3
  1. Department of Chemistry, Faculty of Mathematics and Natural Sciences, Pattimura University, Ambon, Indonesia
  2. Southern Cross University, Lismore, NSW, Australia
  3. Department of Fisheries and Marine Science, Pattimura University, Ambon, Indonesia

Mercury is in demand for use in the small-scale gold mining sector across many countries of the world. Elemental mercury is used to extract gold from ore through the formation of a mercury-gold amalgam. The amalgam is then heated to vaporise the mercury and leave the recovered gold.  Yet mercury supply is limited as The Minamata Convention on Mercury requires the 141-member Parties (including Indonesia) to phase out existing mercury mining. This has led to the occurrence of small-scale mercury mining in areas of mercury rich mineralogy.  Artisanal mining accounts for as much as 80 percent of the mercury now produced annually worldwide. We investigated the environmental distribution and characteristics of mercury in soils and sediments associated with cinnabar mining on Seram Island, Indonesia. The extraction process on-site uses sluice boxes and large quantities of water. Panning in the ocean was also observed in the local community. Once collected, the cinnabar is transported to Java for processing into elemental mercury, which is sold to small-scale gold mining operators in the region. Mercury in waste rock was up to 5630 mg/Kg, although bioavailability was relatively low (<0.04%) but still 2 mg/Kg. There was localised enrichment around Hulong (Total Hg 811 mg/Kg) and Mount Tembaga (Total Hg 825-838 mg/Kg). Sediments in creeks and estuaries contained up to 55mg/Kg and bioavailability was variable. Assessments of soil/sediment characteristics including grain size, total organic carbon, bioavailability and mineralogy, will be used to discuss the long-term implications of mercury toxicity further.