Indonesian artisanal and small-scale gold mining activities (ASGM) have been described for the islands of Borneo (Kalimantan) and Sulawesi. But the increased gold price over recent years has seen operations extend to the islands of Lombok and Sumbawa. For the current research, an environmental assessment was conducted across three new ASGM locations. Gold is recovered by miners through a two-stage process of whole-ore amalgamation and cyanidation. Waste (tailings) is discharged to land or sea with no concern for contaminants in the tailings. The gold grade of ore is up to 5000 mg kg(-1). The mean gold grade of the amalgamation tailings is 7 mg kg(-1), dropping to 1.2 mg kg(-1) for the cyanidation tailings. The mean mercury concentration of the amalgamation tailings is about 3000 mg kg(-1) and greater than 1600 mg kg(-1) for the cyanidation tailings. Samples of paddy rice grain collected adjacent to cyanidation tailings ponds showed methyl mercury concentrations greater than 100 ng g(-1). This is five times above the Chinese permissible level for total mercury in food crops. The mean total mercury concentration in hair of Lombok ASGM workers was greater than that in a non-exposed population; however there was no difference in methyl mercury concentration. This indicates the primary pathway of mercury exposure is inhalation of volatile mercury in the atmosphere. Future exposure may come from ingestion of methyl mercury contaminated rice where discharge of cyanide tailings to paddies continues. To protect the environment and to enhance the sustainability of ASGM, appropriate tailings management must be implemented. The gold grade of the tailings indicates that the residual value might be recoverable with appropriate technology. Ongoing research is investigating systems such as phytoextraction that might assist ASGM operators in Lombok and Sumbawa to improve their environmental performance.

Background. Mercury is a toxic metal with effects on human health ranging from acute to chronic in a very short time of exposure. Artisanal and small-scale gold mining (ASGM) is the main source of direct human exposure to mercury. Human exposure to mercury (Hg) can occur through both direct inhalation of mercury vapor and consumption of material taken from contaminated areas. To protect the health of ASGM workers and surrounding communities, a health assessment of mercury exposure and its effects is urgently needed. However, analysis of hair and urine samples as a proof test for mercury toxicity is very expensive. Therefore other tests must be considered to identify the first symptoms of mercury toxicity in miners and the surrounding community. Objectives. The present study aimed to determine the effects of mercury exposure on renal function along with the hematological parameters of gold miners and the community as a first indication of mercury exposure symptoms. Methods. The study was designed as a purposive field sampling study and was conducted in 3 main villages in Sekotong District, West Lombok Regency, West Nusa Tenggara Province, Indonesia. The 100 subjects were miners that have been exposed to mercury for at least 5 years and their wives and children (non-miners) who lived around the gold processing area. Blood and urine samples were then obtained from the subjects. The miners and non-miners were questioned about their mercury exposure over the previous 5 years, duration of exposure, and how mercury was handled in their daily life. Blood and urine samples were collected at the time of the study, around 10 ml of urine and 0.1 ml of blood (2 drops) were collected per subject. In order to determine the parallel results between the blood-urine and hair results, hair from the miners was collected at a different time for analysis. Results. The results showed that the subjects had low proteinuria, hemoglobin and hematocrit concentrations as a consequence of chronic mercury intoxication. This finding was parallel with results of high mercury concentrations in urine (>7 – 273.3 μg/l) and miners' hair (>1 – 12.93 μg/g). Miners and non-miners in the exposure area were found to have proteinuria levels of more than 0.3 g/L. Proteinuria (≥0.3 g/L) was observed in 92.6% of miners and 72.4% of non-miners. Conclusions. The results of the present study suggest that urinalysis of proteinuria and hemoglobin values can be used as a screening test to detect renal impairment due to mercury intoxication.

Artisanal Small-Scale Gold Mining (ASGM) obviously contributes to serious environmental and health issue for miners, nearby populations, and larger community when the use of mercury (Hg) occurs. Mercury amalgamation is used as a gold recovery technique by 10-12 million ASGM miners around the world and a predicted around 1000 tonnes of mercury are discharged into the environment every year as a result of poor mining practices. Exposure to mercury can cause serious health effects for future generation, and miners and their families are vulnarable group to expose with mercury vapor and methyl mercury contaminated food in ASGM areas, resulting in increase of levels of mercury in human specimens. Thus, investigating the the effects of mercury on the environment and people health are urgently necessary for developing a better solution to eliminate further mercury contamination to environment in West Nusa Tenggara (WNT) Province. A field survey had been conducted for this research in two main ASGM spots in WNT Province: Sekotong-Lombok island and Taliwang-Sumbawa island. As part of the study, an initial health survey and socio-economic of workers/miners was conducted. Volunteer participants at sampling locations across Sekotong-Lombok and TaliwangSumbawa (exposed; indirect exposed; non exposed groups) answered a questionnaire, and allowed the sampling of hair for subsequent analysis. The ore, tailing, plants and soil samples were also collected for investigating Hg concentration on the substances. The results found that the impact of ASGM on increasing economic activity leading to jobs, income and opportunities for social development is positive. However, there is risk of contamination in soil and plants environment through mining activity and high Hg concentration discovered in human body in a short time of ASGM activity. The environmental sustainability of mining can be better regulated within legalised areas. Environmental monitoring will define unacceptable risk and allow for advanced implementation of remedial measures before an uncontrollable disaster occurs.

Background. The primary environmental risk associated with artisanal small-scale gold mining (ASGM) activities in Sekotong and Taliwang is waste discharged directly into the environment. This waste contains variable concentrations of heavy metals and a high level of mercury. When these elements are released into the environment, plants and animals can be contaminated. If mercury is methylated to methylmercury, levels can increase in concentration at each level of the food chain (biomagnify). Fish are a primary risk vector for methylmercury poisoning in humans, and represent a significant source of protein for the Sekotong and Taliwang communities. Objectives. The present study aimed to identify the concentration of mercury in fish from ASGM sites in Sekotong and Taliwang. Methods. Descriptive research was used to describe the mercury concentrations of fish in the present study. The fish species collected for the samples represented commercially available fish most commonly consumed by the community on a daily basis. Results. In Sekotong's ASGM area, the mercury concentration in Pilsbryoconcha exilis tissue was 596 ppb, 721 ppb for Sephia officinalis and 50% of the Euthynnus affinis samples had a high level of mercury, above the World Health Organization (WHO) maximum permissable limit for the sale of fish for human consumption of 0.5 ppb. Conclusions. Some fish species from the studied ASGM sites had high mercury concentrations above the maximum permissible mercury concentration in edible fish tissue. The risks associated with mercury exposure from fish consumption threaten community health. Ethics Approval. All experiments were performed in accordance with relevant local guidelines and regulations. Competing Interests. The authors declare no competing financial interests.

Abstract:Mine tailings are generally disposed of by artisanal and small scale gold miners in poorly constructed containment areas and this leads to environmental risk. Gold phytomining could be a possible option for tailings management at artisanal and small-scale gold mining (ASGM) locations where plants accumulate residual gold in their above ground biomass. The value of metal recovered from plants could offset some of the costs of environmental management. Getting gold into plants has been repeatedly demonstrated by many research groups; however, a simple working technology to get gold out of plants is less well described. A field experiment to assess the relevance of the technology to artisanal miners was conducted in Central Lombok, Indonesia between April and June 2015. Tobacco was planted in cyanidation tailings (1 mg/kg gold) and grown for 2.5 months before the entire plot area was irrigated with NaCN to induce metal uptake. Biomass was then harvested (100 kg), air dried, and ashed by miners in equipment currently used to ash activated carbon at the end of a cyanide leach circuit. Borax and silver as a collector metal were added to the tobacco ash and smelted at high temperature to extract metals from the ash. The mass of the final bullion (39 g) was greater than the mass of silver used as a collector (31 g), indicating recovery of metals from the biomass through the smelt process. The gold yield of this trial was low (1.2 mg/kg dry weight biomass concentration), indicating that considerable work must still be done to optimise valuable metal recovery by plants at the field scale. However, the described method to process the biomass was technically feasible, and represents a valid technique that artisanal and small-scale gold miners are willing to adopt if the economic case is good.