Artisanal small-scale gold mining (ASGM) is the largest source of global mercury (Hg) emissions. This study investigated Hg contamination in water, soil, sediment, fish, and cassava plants around ASGM sites in Gunung Pongkor, West Java, Indonesia. Hg concentration ranged from 0.06 to 4.49 µg/L in water; 0.420 to 144 mg/kg dw in soil; 0.920 to 150 mg/kg dw in sediment; 0.259 to 1.23 mg/kg dw in fish; 0.097 to 5.09 mg/kg dw in cassava root; and 0.350 to 8.84 mg/kg dw in cassava leaf. Geo-accumulation index (Igeo) analysis revealed moderate to heavy soil contamination upstream, likely due to direct ASGM input. In contrast, sediment Igeo values indicated heavy contamination downstream, suggesting Hg transport and sedimentation. Bioconcentration factors (BCFs) in fish were predominantly high in downstream and midstream areas, indicating enhanced Hg bioavailability. Bioaccumulation factors (BAFs) in cassava were higher in upstream areas. Health risk assessment, based on the Hazard Quotient (HQ) and Hazard Index (HI), identified ingestion as the primary exposure route, with children exhibiting significantly higher risks than adults. These findings highlight the significant Hg contamination associated with ASGM in Gunung Pongkor and emphasize the need for targeted mitigation strategies to protect human and environmental health.

Mercury (Hg) pollution from artisanal and small-scale gold mining (ASGM) is a global environmental and public health concern. In Indonesia, ASGM remains widespread, yet assessments of multimedia contamination and health risks are limited. This study quantified Hg concentration in water, sediment, soil, fish, and cassava to evaluate environmental pollution and potential health risks in Waluran, Sukabumi, Indonesia. Mercury concentration in ASGM was higher than in the reference area, especially in fish (median: 4.76 mg/kg dw), cassava leaves (median: 15.7 mg/kg dw), and tailing sediments (median: 171 mg/kg dw). A remarkably high Hg concentration (9760 mg/kg dw) was detected in soil from amalgam-burning spots. An elevated Hg concentration was observed in the reference area, suggesting widespread contamination and potential for long-range dispersion. Over 85% of ASGM samples were categorized as heavily to extremely contaminated by the geo-accumulation index (I_geo). Bioaccumulation assessment indicated a high bioconcentration factor (BCF) in fish and moderate bioaccumulation factor (BAF) in cassava roots. Hazard Quotients (HQ) were greater than 1 for most exposure pathways in both adults and children, with the greatest risk deriving from cassava leaf consumption. These findings indicate severe Hg contamination within ASGM-affected communities and underscore the urgent need for public health interventions, environmental monitoring, and strengthened regulations to reduce Hg exposure in Indonesia.

Mercury is used in artisanal and small-scale gold mining (ASGM) to extract gold by forming an amalgam. This raises considerable concern about mercury pollution in the surrounding environment and plants. This study aimed to investigate mercury concentrations in soil and cacao in the ASGM area of Ghana and to evaluate the human health risk of mercury in cacao. Agricultural soil and cacao (root, leaf, bean, and pod) samples were collected from three ASGM communities (Manso Abore, Nweneso No. 1, and Nweneso No. 2) in the Ashanti Region of Ghana. The mean total mercury concentrations in the soil were 76±36 µg/kg dry weight (n=42), corresponding to moderate contamination by the contamination factor. In the cacao samples, the highest mean total mercury concentration was found in the roots (211 µg/kg dry weight, n=12) and lowest in the beans (27 µg/kg dry weight, n=12). The bioaccumulation and transfer factors indicated a high accumulation of mercury in the roots of cacao (bioaccumulation factor=3.1) from the soil but a lesser accumulation in the aerial parts from the roots (transfer factor<1). The health risk assessment from the ingestion of cacao beans indicated no possibility of noncarcinogenic health effects (hazard quotient<1). Continuous mercury pollution may lead to accumulation along the food chain, which may be detrimental to human health. Therefore, strict measures and monitoring in ASGM communities are needed to protect human health.

Cacao is an important agricultural crop in Ghana, but is grown even in artisanal small scale gold mining (ASGM) area using mercury (Hg) during the amalgamation process. This study investigated Hg concentration in agricultural soil and cacao plant in three ASGM communities in the Ashanti Region of Ghana to evaluate transfer of Hg from soil to cacao and health risk by ingesting of cacao beans. As for the soil samples, the mean Hg concentration was 76 ± 36 µg/kg dw (n = 42), corresponding to moderate contamination by the contamination factor. As for the cacao samples (n = 12 each), the highest mean Hg concentration was found in roots (211 µg/kg dw) and followed by leaves (138 µg/kg dw), pods (40 µg/kg dw) and beans (27 µg/kg dw). Significant correlations were observed between the cacao samples (p < 0.05), but not with the soil samples. indicating accumulation does not only depend on contaminated soil but also the type of plant, its ability to absorb and atmospheric deposition. Data analysis using the bioaccumulation factor (BAF) and the transfer factor (TF) indicated that Hg was highly accumulated from the soil to the root of cacao (BAF = 3.1) but did not highly transfer from the root to the aerial parts (TF < 1). The health risk assessment for ingestion of cacao beans showed that the hazard quotient was less than 1, indicating that there is no possibility of non-carcinogenic health effect.